Merge branch 'master' into temp-multi-function-procedure

59 files changed, 2039 insertions, 1121 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2868324bf46..5a555876d21 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1598,6 +1598,10 @@ elseif(CMAKE_C_COMPILER_ID MATCHES "Clang")
   ADD_CHECK_C_COMPILER_FLAG(C_WARNINGS C_WARN_UNUSED_PARAMETER -Wunused-parameter)
 
   ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_ALL -Wall)
+  # Designated initializer is a C++20 feature & breaks MSVC build. Dropping MSVC 2019 or
+  # updating to C++20 allows removing this.
+  ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_CXX20_DESIGNATOR -Wc++20-designator)
+
   ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_AUTOLOGICAL_COMPARE -Wno-tautological-compare)
   ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_UNKNOWN_PRAGMAS     -Wno-unknown-pragmas)
   ADD_CHECK_CXX_COMPILER_FLAG(CXX_WARNINGS CXX_WARN_NO_CHAR_SUBSCRIPTS     -Wno-char-subscripts)
diff --git a/build_files/cmake/Modules/FindZstd.cmake b/build_files/cmake/Modules/FindZstd.cmake
new file mode 100644
index 00000000000..84606d01f44
--- /dev/null
+++ b/build_files/cmake/Modules/FindZstd.cmake
@@ -0,0 +1,66 @@
+# - Find Zstd library
+# Find the native Zstd includes and library
+# This module defines
+#  ZSTD_INCLUDE_DIRS, where to find zstd.h, Set when
+#                     ZSTD_INCLUDE_DIR is found.
+#  ZSTD_LIBRARIES, libraries to link against to use Zstd.
+#  ZSTD_ROOT_DIR, The base directory to search for Zstd.
+#                 This can also be an environment variable.
+#  ZSTD_FOUND, If false, do not try to use Zstd.
+#
+# also defined, but not for general use are
+#  ZSTD_LIBRARY, where to find the Zstd library.
+
+#=============================================================================
+# Copyright 2019 Blender Foundation.
+#
+# Distributed under the OSI-approved BSD License (the "License");
+# see accompanying file Copyright.txt for details.
+#
+# This software is distributed WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the License for more information.
+#=============================================================================
+
+# If ZSTD_ROOT_DIR was defined in the environment, use it.
+IF(NOT ZSTD_ROOT_DIR AND NOT $ENV{ZSTD_ROOT_DIR} STREQUAL "")
+  SET(ZSTD_ROOT_DIR $ENV{ZSTD_ROOT_DIR})
+ENDIF()
+
+SET(_zstd_SEARCH_DIRS
+  ${ZSTD_ROOT_DIR}
+)
+
+FIND_PATH(ZSTD_INCLUDE_DIR
+  NAMES
+    zstd.h
+  HINTS
+    ${_zstd_SEARCH_DIRS}
+  PATH_SUFFIXES
+    include
+)
+
+FIND_LIBRARY(ZSTD_LIBRARY
+  NAMES
+    zstd
+  HINTS
+    ${_zstd_SEARCH_DIRS}
+  PATH_SUFFIXES
+    lib64 lib
+  )
+
+# handle the QUIETLY and REQUIRED arguments and set ZSTD_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Zstd DEFAULT_MSG
+    ZSTD_LIBRARY ZSTD_INCLUDE_DIR)
+
+IF(ZSTD_FOUND)
+  SET(ZSTD_LIBRARIES ${ZSTD_LIBRARY})
+  SET(ZSTD_INCLUDE_DIRS ${ZSTD_INCLUDE_DIR})
+ENDIF()
+
+MARK_AS_ADVANCED(
+  ZSTD_INCLUDE_DIR
+  ZSTD_LIBRARY
+)
diff --git a/build_files/cmake/platform/platform_apple.cmake b/build_files/cmake/platform/platform_apple.cmake
index dceafb236de..2bfdc84ec2a 100644
--- a/build_files/cmake/platform/platform_apple.cmake
+++ b/build_files/cmake/platform/platform_apple.cmake
@@ -441,6 +441,9 @@ if(WITH_HARU)
   endif()
 endif()
 
+set(ZSTD_ROOT_DIR ${LIBDIR}/zstd)
+find_package(Zstd REQUIRED)
+
 if(EXISTS ${LIBDIR})
   without_system_libs_end()
 endif()
diff --git a/build_files/cmake/platform/platform_unix.cmake b/build_files/cmake/platform/platform_unix.cmake
index 7f62399ac4f..fc0c37e4c8b 100644
--- a/build_files/cmake/platform/platform_unix.cmake
+++ b/build_files/cmake/platform/platform_unix.cmake
@@ -99,6 +99,7 @@ endif()
 find_package_wrapper(JPEG REQUIRED)
 find_package_wrapper(PNG REQUIRED)
 find_package_wrapper(ZLIB REQUIRED)
+find_package_wrapper(Zstd REQUIRED)
 find_package_wrapper(Freetype REQUIRED)
 
 if(WITH_PYTHON)
diff --git a/build_files/cmake/platform/platform_win32.cmake b/build_files/cmake/platform/platform_win32.cmake
index 3773aaaffed..d44ef691d1b 100644
--- a/build_files/cmake/platform/platform_win32.cmake
+++ b/build_files/cmake/platform/platform_win32.cmake
@@ -873,3 +873,6 @@ if(WITH_HARU)
     set(WITH_HARU OFF)
   endif()
 endif()
+
+set(ZSTD_INCLUDE_DIRS ${LIBDIR}/zstd/include)
+set(ZSTD_LIBRARIES ${LIBDIR}/zstd/lib/zstd_static.lib)
diff --git a/doc/python_api/requirements.txt b/doc/python_api/requirements.txt
index a854d2a267b..b5a9d15bf7b 100644
--- a/doc/python_api/requirements.txt
+++ b/doc/python_api/requirements.txt
@@ -1,13 +1,13 @@
-sphinx==3.5.4
+sphinx==4.1.1
 
 # Sphinx dependencies that are important
-Jinja2==2.11.3
-Pygments==2.9.0
-docutils==0.16
+Jinja2==3.0.1
+Pygments==2.10.0
+docutils==0.17.1
 snowballstemmer==2.1.0
 babel==2.9.1
-requests==2.25.1
+requests==2.26.0
 
 # Only needed to match the theme used for the official documentation.
 # Without this theme, the default theme will be used.
-sphinx_rtd_theme==0.5.2
+sphinx_rtd_theme==1.0.0rc1
diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py
index ac0aca57028..0c3af3fabeb 100644
--- a/intern/cycles/blender/addon/properties.py
+++ b/intern/cycles/blender/addon/properties.py
@@ -408,7 +408,7 @@ class CyclesRenderSettings(bpy.types.PropertyGroup):
 
     adaptive_threshold: FloatProperty(
         name="Adaptive Sampling Threshold",
-        description="Noise level step to stop sampling at, lower values reduce noise the cost of render time. Zero for automatic setting based on number of AA samples",
+        description="Noise level step to stop sampling at, lower values reduce noise at the cost of render time. Zero for automatic setting based on number of AA samples",
         min=0.0, max=1.0,
         default=0.0,
         precision=4,
diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index 2dbebac4cc3..a7eae421b55 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -523,6 +523,9 @@ void BlenderSync::sync_procedural(BL::Object &b_ob,
 
   procedural->set_scale(cache_file.scale());
 
+  procedural->set_use_prefetch(cache_file.use_prefetch());
+  procedural->set_prefetch_cache_size(cache_file.prefetch_cache_size());
+
   /* create or update existing AlembicObjects */
   ustring object_path = ustring(b_mesh_cache.object_path());
 
diff --git a/intern/cycles/render/alembic.cpp b/intern/cycles/render/alembic.cpp
index 81f47256739..69bc0712674 100644
--- a/intern/cycles/render/alembic.cpp
+++ b/intern/cycles/render/alembic.cpp
@@ -25,6 +25,7 @@
 #include "render/shader.h"
 
 #include "util/util_foreach.h"
+#include "util/util_logging.h"
 #include "util/util_progress.h"
 #include "util/util_transform.h"
 #include "util/util_vector.h"
@@ -211,6 +212,35 @@ void CachedData::set_time_sampling(TimeSampling time_sampling)
   }
 }
 
+size_t CachedData::memory_used() const
+{
+  size_t mem_used = 0;
+
+  mem_used += curve_first_key.memory_used();
+  mem_used += curve_keys.memory_used();
+  mem_used += curve_radius.memory_used();
+  mem_used += curve_shader.memory_used();
+  mem_used += num_ngons.memory_used();
+  mem_used += shader.memory_used();
+  mem_used += subd_creases_edge.memory_used();
+  mem_used += subd_creases_weight.memory_used();
+  mem_used += subd_face_corners.memory_used();
+  mem_used += subd_num_corners.memory_used();
+  mem_used += subd_ptex_offset.memory_used();
+  mem_used += subd_smooth.memory_used();
+  mem_used += subd_start_corner.memory_used();
+  mem_used += transforms.memory_used();
+  mem_used += triangles.memory_used();
+  mem_used += uv_loops.memory_used();
+  mem_used += vertices.memory_used();
+
+  for (const CachedAttribute &attr : attributes) {
+    mem_used += attr.data.memory_used();
+  }
+
+  return mem_used;
+}
+
 static M44d convert_yup_zup(const M44d &mtx, float scale_mult)
 {
   V3d scale, shear, rotation, translation;
@@ -706,6 +736,9 @@ NODE_DEFINE(AlembicProcedural)
 
   SOCKET_NODE_ARRAY(objects, "Objects", AlembicObject::get_node_type());
 
+  SOCKET_BOOLEAN(use_prefetch, "Use Prefetch", true);
+  SOCKET_INT(prefetch_cache_size, "Prefetch Cache Size", 4096);
+
   return type;
 }
 
@@ -823,6 +856,30 @@ void AlembicProcedural::generate(Scene *scene, Progress &progress)
     }
   }
 
+  if (use_prefetch_is_modified()) {
+    if (!use_prefetch) {
+      for (Node *node : objects) {
+        AlembicObject *object = static_cast<AlembicObject *>(node);
+        object->clear_cache();
+      }
+    }
+  }
+
+  if (prefetch_cache_size_is_modified()) {
+    /* Check whether the current memory usage fits in the new requested size,
+     * abort the render if it is any higher. */
+    size_t memory_used = 0ul;
+    for (Node *node : objects) {
+      AlembicObject *object = static_cast<AlembicObject *>(node);
+      memory_used += object->get_cached_data().memory_used();
+    }
+
+    if (memory_used > get_prefetch_cache_size_in_bytes()) {
+      progress.set_error("Error: Alembic Procedural memory limit reached");
+      return;
+    }
+  }
+
   build_caches(progress);
 
   foreach (Node *node, objects) {
@@ -1300,6 +1357,8 @@ void AlembicProcedural::walk_hierarchy(
 
 void AlembicProcedural::build_caches(Progress &progress)
 {
+  size_t memory_used = 0;
+
   for (Node *node : objects) {
     AlembicObject *object = static_cast<AlembicObject *>(node);
 
@@ -1353,7 +1412,18 @@ void AlembicProcedural::build_caches(Progress &progress)
     if (scale_is_modified() || object->get_cached_data().transforms.size() == 0) {
       object->setup_transform_cache(object->get_cached_data(), scale);
     }
+
+    memory_used += object->get_cached_data().memory_used();
+
+    if (use_prefetch) {
+      if (memory_used > get_prefetch_cache_size_in_bytes()) {
+        progress.set_error("Error: Alembic Procedural memory limit reached");
+        return;
+      }
+    }
   }
+
+  VLOG(1) << "AlembicProcedural memory usage : " << string_human_readable_size(memory_used);
 }
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/alembic.h b/intern/cycles/render/alembic.h
index 9c58af720f6..8e166a5ab04 100644
--- a/intern/cycles/render/alembic.h
+++ b/intern/cycles/render/alembic.h
@@ -272,6 +272,21 @@ template<typename T> class DataStore {
     node->set(*socket, value);
   }
 
+  size_t memory_used() const
+  {
+    if constexpr (is_array<T>::value) {
+      size_t mem_used = 0;
+
+      for (const T &array : data) {
+        mem_used += array.size() * sizeof(array[0]);
+      }
+
+      return mem_used;
+    }
+
+    return data.size() * sizeof(T);
+  }
+
  private:
   const TimeIndexPair &get_index_for_time(double time) const
   {
@@ -332,6 +347,8 @@ struct CachedData {
   void invalidate_last_loaded_time(bool attributes_only = false);
 
   void set_time_sampling(Alembic::AbcCoreAbstract::TimeSampling time_sampling);
+
+  size_t memory_used() const;
 };
 
 /* Representation of an Alembic object for the AlembicProcedural.
@@ -482,6 +499,13 @@ class AlembicProcedural : public Procedural {
    * software. */
   NODE_SOCKET_API(float, scale)
 
+  /* Cache controls */
+  NODE_SOCKET_API(bool, use_prefetch)
+
+  /* Memory limit for the cache, if the data does not fit within this limit, rendering is aborted.
+   */
+  NODE_SOCKET_API(int, prefetch_cache_size)
+
   AlembicProcedural();
   ~AlembicProcedural();
 
@@ -531,6 +555,12 @@ class AlembicProcedural : public Procedural {
   void read_subd(AlembicObject *abc_object, Alembic::AbcGeom::Abc::chrono_t frame_time);
 
   void build_caches(Progress &progress);
+
+  size_t get_prefetch_cache_size_in_bytes() const
+  {
+    /* prefetch_cache_size is in megabytes, so convert to bytes. */
+    return static_cast<size_t>(prefetch_cache_size) * 1024 * 1024;
+  }
 };
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/alembic_read.cpp b/intern/cycles/render/alembic_read.cpp
index c53ec668938..b105af63b44 100644
--- a/intern/cycles/render/alembic_read.cpp
+++ b/intern/cycles/render/alembic_read.cpp
@@ -44,9 +44,19 @@ static set<chrono_t> get_relevant_sample_times(AlembicProcedural *proc,
     return result;
   }
 
-  // load the data for the entire animation
-  const double start_frame = static_cast<double>(proc->get_start_frame());
-  const double end_frame = static_cast<double>(proc->get_end_frame());
+  double start_frame;
+  double end_frame;
+
+  if (proc->get_use_prefetch()) {
+    // load the data for the entire animation
+    start_frame = static_cast<double>(proc->get_start_frame());
+    end_frame = static_cast<double>(proc->get_end_frame());
+  }
+  else {
+    // load the data for the current frame
+    start_frame = static_cast<double>(proc->get_frame());
+    end_frame = start_frame;
+  }
 
   const double frame_rate = static_cast<double>(proc->get_frame_rate());
   const double start_time = start_frame / frame_rate;
diff --git a/intern/ghost/GHOST_IEvent.h b/intern/ghost/GHOST_IEvent.h
index bcccd536ebd..239eea21088 100644
--- a/intern/ghost/GHOST_IEvent.h
+++ b/intern/ghost/GHOST_IEvent.h
@@ -32,10 +32,10 @@ class GHOST_IWindow;
 /**
  * Interface class for events received from GHOST.
  * You should not need to inherit this class. The system will pass these events
- * to the GHOST_IEventConsumer::processEvent() method of event consumers.<br>
- * Use the getType() method to retrieve the type of event and the getData()
+ * to the #GHOST_IEventConsumer::processEvent() method of event consumers.<br>
+ * Use the #getType() method to retrieve the type of event and the #getData()
  * method to get the event data out. Using the event type you can cast the
- * event data to the correct event dat structure.
+ * event data to the correct event data structure.
  * \see GHOST_IEventConsumer#processEvent
  * \see GHOST_TEventType
  */
diff --git a/intern/ghost/intern/GHOST_SystemWin32.cpp b/intern/ghost/intern/GHOST_SystemWin32.cpp
index 347067eae50..f44107ee000 100644
--- a/intern/ghost/intern/GHOST_SystemWin32.cpp
+++ b/intern/ghost/intern/GHOST_SystemWin32.cpp
@@ -1741,7 +1741,7 @@ LRESULT WINAPI GHOST_SystemWin32::s_wndProc(HWND hwnd, UINT msg, WPARAM wParam,
         case WM_MOUSELEAVE: {
           window->m_mousePresent = false;
           if (window->getTabletData().Active == GHOST_kTabletModeNone) {
-            processCursorEvent(window);
+            event = processCursorEvent(window);
           }
           GHOST_Wintab *wt = window->getWintab();
           if (wt) {
diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c
index 9168e7aa19c..2f9eb0753ac 100644
--- a/source/blender/blenfont/intern/blf.c
+++ b/source/blender/blenfont/intern/blf.c
@@ -108,7 +108,6 @@ void BLF_cache_clear(void)
     FontBLF *font = global_font[i];
     if (font) {
       blf_glyph_cache_clear(font);
-      blf_kerning_cache_clear(font);
     }
   }
 }
diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c
index 00d3cfb09eb..75a2e893119 100644
--- a/source/blender/blenfont/intern/blf_font.c
+++ b/source/blender/blenfont/intern/blf_font.c
@@ -72,6 +72,38 @@ static SpinLock ft_lib_mutex;
 static SpinLock blf_glyph_cache_mutex;
 
 /* -------------------------------------------------------------------- */
+/** \name FreeType Utilities (Internal)
+ * \{ */
+
+/**
+ * Convert a FreeType 26.6 value representing an unscaled design size to pixels.
+ * This is an exact copy of the scaling done inside FT_Get_Kerning when called
+ * with #FT_KERNING_DEFAULT, including arbitrary resizing for small fonts.
+ */
+static int blf_unscaled_F26Dot6_to_pixels(FontBLF *font, FT_Pos value)
+{
+  /* Scale value by font size using integer-optimized multiplication. */
+  FT_Long scaled = FT_MulFix(value, font->face->size->metrics.x_scale);
+
+  /* FreeType states that this '25' has been determined heuristically. */
+  if (font->face->size->metrics.x_ppem < 25) {
+    scaled = FT_MulDiv(scaled, font->face->size->metrics.x_ppem, 25);
+  }
+
+  /* Copies of internal FreeType macros needed here. */
+#define FT_PIX_FLOOR(x) ((x) & ~63)
+#define FT_PIX_ROUND(x) FT_PIX_FLOOR((x) + 32)
+
+  /* Round to even 64ths, then divide by 64. */
+  return (int)FT_PIX_ROUND(scaled) >> 6;
+
+#undef FT_PIX_FLOOR
+#undef FT_PIX_ROUND
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Glyph Batching
  * \{ */
 
@@ -257,67 +289,8 @@ static void blf_batch_draw_end(void)
 /** \} */
 
 /* -------------------------------------------------------------------- */
-
-int blf_font_init(void)
-{
-  memset(&g_batch, 0, sizeof(g_batch));
-  BLI_spin_init(&ft_lib_mutex);
-  BLI_spin_init(&blf_glyph_cache_mutex);
-  return FT_Init_FreeType(&ft_lib);
-}
-
-void blf_font_exit(void)
-{
-  FT_Done_FreeType(ft_lib);
-  BLI_spin_end(&ft_lib_mutex);
-  BLI_spin_end(&blf_glyph_cache_mutex);
-  blf_batch_draw_exit();
-}
-
-void blf_font_size(FontBLF *font, unsigned int size, unsigned int dpi)
-{
-  GlyphCacheBLF *gc;
-  FT_Error err;
-
-  blf_glyph_cache_acquire(font);
-
-  gc = blf_glyph_cache_find(font, size, dpi);
-  if (gc) {
-    /* Optimization: do not call FT_Set_Char_Size if size did not change. */
-    if (font->size == size && font->dpi == dpi) {
-      blf_glyph_cache_release(font);
-      return;
-    }
-  }
-
-  err = FT_Set_Char_Size(font->face, 0, ((FT_F26Dot6)(size)) * 64, dpi, dpi);
-  if (err) {
-    /* FIXME: here we can go through the fixed size and choice a close one */
-    printf("The current font don't support the size, %u and dpi, %u\n", size, dpi);
-
-    blf_glyph_cache_release(font);
-    return;
-  }
-
-  font->size = size;
-  font->dpi = dpi;
-
-  if (!gc) {
-    blf_glyph_cache_new(font);
-  }
-  blf_glyph_cache_release(font);
-}
-
-static void blf_font_ensure_ascii_kerning(FontBLF *font, GlyphCacheBLF *gc)
-{
-  if (font->kerning_cache || !FT_HAS_KERNING(font->face)) {
-    return;
-  }
-  font->kerning_cache = blf_kerning_cache_find(font);
-  if (!font->kerning_cache) {
-    font->kerning_cache = blf_kerning_cache_new(font, gc);
-  }
-}
+/** \name Glyph Stepping Utilities (Internal)
+ * \{ */
 
 /* Fast path for runs of ASCII characters. Given that common UTF-8
  * input will consist of an overwhelming majority of ASCII
@@ -355,22 +328,40 @@ BLI_INLINE void blf_kerning_step_fast(FontBLF *font,
                                       const uint c,
                                       int *pen_x_p)
 {
-  /* `blf_font_ensure_ascii_kerning(font, gc);` must be called before this function. */
-  BLI_assert(font->kerning_cache != NULL || !FT_HAS_KERNING(font->face));
+  if (!FT_HAS_KERNING(font->face) || g_prev == NULL) {
+    return;
+  }
 
-  if (g_prev != NULL && FT_HAS_KERNING(font->face)) {
-    if ((c_prev < KERNING_CACHE_TABLE_SIZE) && (c < GLYPH_ASCII_TABLE_SIZE)) {
-      *pen_x_p += font->kerning_cache->ascii_table[c][c_prev];
-    }
-    else {
-      FT_Vector delta;
-      if (FT_Get_Kerning(font->face, g_prev->idx, g->idx, FT_KERNING_DEFAULT, &delta) == 0) {
-        *pen_x_p += (int)delta.x >> 6;
-      }
-    }
+  FT_Vector delta = {KERNING_ENTRY_UNSET};
+
+  /* Get unscaled kerning value from our cache if ASCII. */
+  if ((c_prev < KERNING_CACHE_TABLE_SIZE) && (c < GLYPH_ASCII_TABLE_SIZE)) {
+    delta.x = font->kerning_cache->ascii_table[c][c_prev];
+  }
+
+  /* If not ASCII or not found in cache, ask FreeType for kerning. */
+  if (UNLIKELY(delta.x == KERNING_ENTRY_UNSET)) {
+    /* Note that this function sets delta values to zero on any error. */
+    FT_Get_Kerning(font->face, g_prev->idx, g->idx, FT_KERNING_UNSCALED, &delta);
+  }
+
+  /* If ASCII we save this value to our cache for quicker access next time. */
+  if ((c_prev < KERNING_CACHE_TABLE_SIZE) && (c < GLYPH_ASCII_TABLE_SIZE)) {
+    font->kerning_cache->ascii_table[c][c_prev] = (int)delta.x;
+  }
+
+  if (delta.x != 0) {
+    /* Convert unscaled design units to pixels and move pen. */
+    *pen_x_p += blf_unscaled_F26Dot6_to_pixels(font, delta.x);
   }
 }
 
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Text Drawing: GPU
+ * \{ */
+
 static void blf_font_draw_ex(FontBLF *font,
                              GlyphCacheBLF *gc,
                              const char *str,
@@ -388,8 +379,6 @@ static void blf_font_draw_ex(FontBLF *font,
     return;
   }
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   blf_batch_draw_begin(font);
 
   while ((i < len) && str[i]) {
@@ -435,8 +424,6 @@ static void blf_font_draw_ascii_ex(
 
   GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   blf_batch_draw_begin(font);
 
   while ((c = *(str++)) && len--) {
@@ -515,6 +502,12 @@ int blf_font_draw_mono(FontBLF *font, const char *str, size_t len, int cwidth)
   return columns;
 }
 
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Text Drawgin: Buffer
+ * \{ */
+
 /* Sanity checks are done by BLF_draw_buffer() */
 static void blf_font_draw_buffer_ex(FontBLF *font,
                                     GlyphCacheBLF *gc,
@@ -536,8 +529,6 @@ static void blf_font_draw_buffer_ex(FontBLF *font,
   int chx, chy;
   int y, x;
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   /* another buffer specific call for color conversion */
 
   while ((i < len) && str[i]) {
@@ -662,6 +653,16 @@ void blf_font_draw_buffer(FontBLF *font, const char *str, size_t len, struct Res
   blf_glyph_cache_release(font);
 }
 
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Text Evaluation: Width to Sting Length
+ *
+ * Use to implement exported functions:
+ * - #BLF_width_to_strlen
+ * - #BLF_width_to_rstrlen
+ * \{ */
+
 static bool blf_font_width_to_strlen_glyph_process(FontBLF *font,
                                                    const uint c_prev,
                                                    const uint c,
@@ -694,8 +695,6 @@ size_t blf_font_width_to_strlen(
   GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
   const int width_i = (int)width;
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   for (i_prev = i = 0, width_new = pen_x = 0, g_prev = NULL, c_prev = 0; (i < len) && str[i];
        i_prev = i, width_new = pen_x, c_prev = c, g_prev = g) {
     g = blf_utf8_next_fast(font, gc, str, &i, &c);
@@ -725,8 +724,6 @@ size_t blf_font_width_to_rstrlen(
   GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
   const int width_i = (int)width;
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   i = BLI_strnlen(str, len);
   s = BLI_str_find_prev_char_utf8(str, &str[i]);
   i = (size_t)((s != NULL) ? s - str : 0);
@@ -759,6 +756,12 @@ size_t blf_font_width_to_rstrlen(
   return i;
 }
 
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Text Evaluation: Glyph Bound Box with Callback
+ * \{ */
+
 static void blf_font_boundbox_ex(FontBLF *font,
                                  GlyphCacheBLF *gc,
                                  const char *str,
@@ -778,8 +781,6 @@ static void blf_font_boundbox_ex(FontBLF *font,
   box->ymin = 32000.0f;
   box->ymax = -32000.0f;
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   while ((i < len) && str[i]) {
     g = blf_utf8_next_fast(font, gc, str, &i, &c);
 
@@ -835,8 +836,165 @@ void blf_font_boundbox(
   blf_glyph_cache_release(font);
 }
 
+void blf_font_width_and_height(FontBLF *font,
+                               const char *str,
+                               size_t len,
+                               float *r_width,
+                               float *r_height,
+                               struct ResultBLF *r_info)
+{
+  float xa, ya;
+  rctf box;
+
+  if (font->flags & BLF_ASPECT) {
+    xa = font->aspect[0];
+    ya = font->aspect[1];
+  }
+  else {
+    xa = 1.0f;
+    ya = 1.0f;
+  }
+
+  if (font->flags & BLF_WORD_WRAP) {
+    blf_font_boundbox__wrap(font, str, len, &box, r_info);
+  }
+  else {
+    blf_font_boundbox(font, str, len, &box, r_info);
+  }
+  *r_width = (BLI_rctf_size_x(&box) * xa);
+  *r_height = (BLI_rctf_size_y(&box) * ya);
+}
+
+float blf_font_width(FontBLF *font, const char *str, size_t len, struct ResultBLF *r_info)
+{
+  float xa;
+  rctf box;
+
+  if (font->flags & BLF_ASPECT) {
+    xa = font->aspect[0];
+  }
+  else {
+    xa = 1.0f;
+  }
+
+  if (font->flags & BLF_WORD_WRAP) {
+    blf_font_boundbox__wrap(font, str, len, &box, r_info);
+  }
+  else {
+    blf_font_boundbox(font, str, len, &box, r_info);
+  }
+  return BLI_rctf_size_x(&box) * xa;
+}
+
+float blf_font_height(FontBLF *font, const char *str, size_t len, struct ResultBLF *r_info)
+{
+  float ya;
+  rctf box;
+
+  if (font->flags & BLF_ASPECT) {
+    ya = font->aspect[1];
+  }
+  else {
+    ya = 1.0f;
+  }
+
+  if (font->flags & BLF_WORD_WRAP) {
+    blf_font_boundbox__wrap(font, str, len, &box, r_info);
+  }
+  else {
+    blf_font_boundbox(font, str, len, &box, r_info);
+  }
+  return BLI_rctf_size_y(&box) * ya;
+}
+
+float blf_font_fixed_width(FontBLF *font)
+{
+  const unsigned int c = ' ';
+
+  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
+  GlyphBLF *g = blf_glyph_search(gc, c);
+  if (!g) {
+    g = blf_glyph_add(font, gc, FT_Get_Char_Index(font->face, c), c);
+
+    /* if we don't find the glyph. */
+    if (!g) {
+      blf_glyph_cache_release(font);
+      return 0.0f;
+    }
+  }
+
+  blf_glyph_cache_release(font);
+  return g->advance;
+}
+
+static void blf_font_boundbox_foreach_glyph_ex(FontBLF *font,
+                                               GlyphCacheBLF *gc,
+                                               const char *str,
+                                               size_t len,
+                                               BLF_GlyphBoundsFn user_fn,
+                                               void *user_data,
+                                               struct ResultBLF *r_info,
+                                               int pen_y)
+{
+  unsigned int c, c_prev = BLI_UTF8_ERR;
+  GlyphBLF *g, *g_prev = NULL;
+  int pen_x = 0;
+  size_t i = 0, i_curr;
+  rcti gbox;
+
+  if (len == 0) {
+    /* early output. */
+    return;
+  }
+
+  while ((i < len) && str[i]) {
+    i_curr = i;
+    g = blf_utf8_next_fast(font, gc, str, &i, &c);
+
+    if (UNLIKELY(c == BLI_UTF8_ERR)) {
+      break;
+    }
+    if (UNLIKELY(g == NULL)) {
+      continue;
+    }
+    blf_kerning_step_fast(font, g_prev, g, c_prev, c, &pen_x);
+
+    gbox.xmin = pen_x;
+    gbox.xmax = gbox.xmin + MIN2(g->advance_i, g->dims[0]);
+    gbox.ymin = pen_y;
+    gbox.ymax = gbox.ymin - g->dims[1];
+
+    pen_x += g->advance_i;
+
+    if (user_fn(str, i_curr, &gbox, g->advance_i, &g->box, g->pos, user_data) == false) {
+      break;
+    }
+
+    g_prev = g;
+    c_prev = c;
+  }
+
+  if (r_info) {
+    r_info->lines = 1;
+    r_info->width = pen_x;
+  }
+}
+void blf_font_boundbox_foreach_glyph(FontBLF *font,
+                                     const char *str,
+                                     size_t len,
+                                     BLF_GlyphBoundsFn user_fn,
+                                     void *user_data,
+                                     struct ResultBLF *r_info)
+{
+  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
+  blf_font_boundbox_foreach_glyph_ex(font, gc, str, len, user_fn, user_data, r_info, 0);
+  blf_glyph_cache_release(font);
+}
+
+/** \} */
+
 /* -------------------------------------------------------------------- */
-/** \name Word-Wrap Support
+/** \name Text Evaluation: Word-Wrap with Callback
  * \{ */
 
 /**
@@ -869,8 +1027,6 @@ static void blf_font_wrap_apply(FontBLF *font,
 
   GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
 
-  blf_font_ensure_ascii_kerning(font, gc);
-
   struct WordWrapVars {
     int wrap_width;
     size_t start, last[2];
@@ -1008,216 +1164,120 @@ void blf_font_draw_buffer__wrap(FontBLF *font,
 
 /** \} */
 
-void blf_font_width_and_height(FontBLF *font,
-                               const char *str,
-                               size_t len,
-                               float *r_width,
-                               float *r_height,
-                               struct ResultBLF *r_info)
+/* -------------------------------------------------------------------- */
+/** \name Text Evaluation: Count Missing Characters
+ * \{ */
+
+int blf_font_count_missing_chars(FontBLF *font,
+                                 const char *str,
+                                 const size_t len,
+                                 int *r_tot_chars)
 {
-  float xa, ya;
-  rctf box;
+  int missing = 0;
+  size_t i = 0;
 
-  if (font->flags & BLF_ASPECT) {
-    xa = font->aspect[0];
-    ya = font->aspect[1];
-  }
-  else {
-    xa = 1.0f;
-    ya = 1.0f;
-  }
+  *r_tot_chars = 0;
+  while (i < len) {
+    unsigned int c;
 
-  if (font->flags & BLF_WORD_WRAP) {
-    blf_font_boundbox__wrap(font, str, len, &box, r_info);
-  }
-  else {
-    blf_font_boundbox(font, str, len, &box, r_info);
+    if ((c = str[i]) < GLYPH_ASCII_TABLE_SIZE) {
+      i++;
+    }
+    else if ((c = BLI_str_utf8_as_unicode_step(str, &i)) != BLI_UTF8_ERR) {
+      if (FT_Get_Char_Index((font)->face, c) == 0) {
+        missing++;
+      }
+    }
+    (*r_tot_chars)++;
   }
-  *r_width = (BLI_rctf_size_x(&box) * xa);
-  *r_height = (BLI_rctf_size_y(&box) * ya);
+  return missing;
 }
 
-float blf_font_width(FontBLF *font, const char *str, size_t len, struct ResultBLF *r_info)
-{
-  float xa;
-  rctf box;
-
-  if (font->flags & BLF_ASPECT) {
-    xa = font->aspect[0];
-  }
-  else {
-    xa = 1.0f;
-  }
+/** \} */
 
-  if (font->flags & BLF_WORD_WRAP) {
-    blf_font_boundbox__wrap(font, str, len, &box, r_info);
-  }
-  else {
-    blf_font_boundbox(font, str, len, &box, r_info);
-  }
-  return BLI_rctf_size_x(&box) * xa;
-}
+/* -------------------------------------------------------------------- */
+/** \name Font Query: Attributes
+ * \{ */
 
-float blf_font_height(FontBLF *font, const char *str, size_t len, struct ResultBLF *r_info)
+int blf_font_height_max(FontBLF *font)
 {
-  float ya;
-  rctf box;
+  int height_max;
 
-  if (font->flags & BLF_ASPECT) {
-    ya = font->aspect[1];
-  }
-  else {
-    ya = 1.0f;
-  }
+  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
+  height_max = gc->glyph_height_max;
 
-  if (font->flags & BLF_WORD_WRAP) {
-    blf_font_boundbox__wrap(font, str, len, &box, r_info);
-  }
-  else {
-    blf_font_boundbox(font, str, len, &box, r_info);
-  }
-  return BLI_rctf_size_y(&box) * ya;
+  blf_glyph_cache_release(font);
+  return height_max;
 }
 
-float blf_font_fixed_width(FontBLF *font)
+int blf_font_width_max(FontBLF *font)
 {
-  const unsigned int c = ' ';
+  int width_max;
 
   GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  GlyphBLF *g = blf_glyph_search(gc, c);
-  if (!g) {
-    g = blf_glyph_add(font, gc, FT_Get_Char_Index(font->face, c), c);
-
-    /* if we don't find the glyph. */
-    if (!g) {
-      blf_glyph_cache_release(font);
-      return 0.0f;
-    }
-  }
+  width_max = gc->glyph_width_max;
 
   blf_glyph_cache_release(font);
-  return g->advance;
+  return width_max;
 }
 
-/* -------------------------------------------------------------------- */
-/** \name Glyph Bound Box with Callback
- * \{ */
-
-static void blf_font_boundbox_foreach_glyph_ex(FontBLF *font,
-                                               GlyphCacheBLF *gc,
-                                               const char *str,
-                                               size_t len,
-                                               BLF_GlyphBoundsFn user_fn,
-                                               void *user_data,
-                                               struct ResultBLF *r_info,
-                                               int pen_y)
+float blf_font_descender(FontBLF *font)
 {
-  unsigned int c, c_prev = BLI_UTF8_ERR;
-  GlyphBLF *g, *g_prev = NULL;
-  int pen_x = 0;
-  size_t i = 0, i_curr;
-  rcti gbox;
-
-  if (len == 0) {
-    /* early output. */
-    return;
-  }
-
-  blf_font_ensure_ascii_kerning(font, gc);
-
-  while ((i < len) && str[i]) {
-    i_curr = i;
-    g = blf_utf8_next_fast(font, gc, str, &i, &c);
-
-    if (UNLIKELY(c == BLI_UTF8_ERR)) {
-      break;
-    }
-    if (UNLIKELY(g == NULL)) {
-      continue;
-    }
-    blf_kerning_step_fast(font, g_prev, g, c_prev, c, &pen_x);
+  float descender;
 
-    gbox.xmin = pen_x;
-    gbox.xmax = gbox.xmin + MIN2(g->advance_i, g->dims[0]);
-    gbox.ymin = pen_y;
-    gbox.ymax = gbox.ymin - g->dims[1];
+  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
+  descender = gc->descender;
 
-    pen_x += g->advance_i;
+  blf_glyph_cache_release(font);
+  return descender;
+}
 
-    if (user_fn(str, i_curr, &gbox, g->advance_i, &g->box, g->pos, user_data) == false) {
-      break;
-    }
+float blf_font_ascender(FontBLF *font)
+{
+  float ascender;
 
-    g_prev = g;
-    c_prev = c;
-  }
+  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
+  ascender = gc->ascender;
 
-  if (r_info) {
-    r_info->lines = 1;
-    r_info->width = pen_x;
-  }
+  blf_glyph_cache_release(font);
+  return ascender;
 }
-void blf_font_boundbox_foreach_glyph(FontBLF *font,
-                                     const char *str,
-                                     size_t len,
-                                     BLF_GlyphBoundsFn user_fn,
-                                     void *user_data,
-                                     struct ResultBLF *r_info)
+
+char *blf_display_name(FontBLF *font)
 {
-  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  blf_font_boundbox_foreach_glyph_ex(font, gc, str, len, user_fn, user_data, r_info, 0);
-  blf_glyph_cache_release(font);
+  if (!font->face->family_name) {
+    return NULL;
+  }
+  return BLI_sprintfN("%s %s", font->face->family_name, font->face->style_name);
 }
 
 /** \} */
 
-int blf_font_count_missing_chars(FontBLF *font,
-                                 const char *str,
-                                 const size_t len,
-                                 int *r_tot_chars)
-{
-  int missing = 0;
-  size_t i = 0;
-
-  *r_tot_chars = 0;
-  while (i < len) {
-    unsigned int c;
+/* -------------------------------------------------------------------- */
+/** \name Font Subsystem Init/Exit
+ * \{ */
 
-    if ((c = str[i]) < GLYPH_ASCII_TABLE_SIZE) {
-      i++;
-    }
-    else if ((c = BLI_str_utf8_as_unicode_step(str, &i)) != BLI_UTF8_ERR) {
-      if (FT_Get_Char_Index((font)->face, c) == 0) {
-        missing++;
-      }
-    }
-    (*r_tot_chars)++;
-  }
-  return missing;
+int blf_font_init(void)
+{
+  memset(&g_batch, 0, sizeof(g_batch));
+  BLI_spin_init(&ft_lib_mutex);
+  BLI_spin_init(&blf_glyph_cache_mutex);
+  return FT_Init_FreeType(&ft_lib);
 }
 
-void blf_font_free(FontBLF *font)
+void blf_font_exit(void)
 {
-  BLI_spin_lock(&blf_glyph_cache_mutex);
-  GlyphCacheBLF *gc;
-
-  while ((gc = BLI_pophead(&font->cache))) {
-    blf_glyph_cache_free(gc);
-  }
-
-  blf_kerning_cache_clear(font);
+  FT_Done_FreeType(ft_lib);
+  BLI_spin_end(&ft_lib_mutex);
+  BLI_spin_end(&blf_glyph_cache_mutex);
+  blf_batch_draw_exit();
+}
 
-  FT_Done_Face(font->face);
-  if (font->filename) {
-    MEM_freeN(font->filename);
-  }
-  if (font->name) {
-    MEM_freeN(font->name);
-  }
-  MEM_freeN(font);
+/** \} */
 
-  BLI_spin_unlock(&blf_glyph_cache_mutex);
-}
+/* -------------------------------------------------------------------- */
+/** \name Font New/Free
+ * \{ */
 
 static void blf_font_fill(FontBLF *font)
 {
@@ -1246,7 +1306,6 @@ static void blf_font_fill(FontBLF *font)
   font->dpi = 0;
   font->size = 0;
   BLI_listbase_clear(&font->cache);
-  BLI_listbase_clear(&font->kerning_caches);
   font->kerning_cache = NULL;
 #if BLF_BLUR_ENABLE
   font->blur = 0;
@@ -1307,6 +1366,17 @@ FontBLF *blf_font_new(const char *name, const char *filename)
   font->name = BLI_strdup(name);
   font->filename = BLI_strdup(filename);
   blf_font_fill(font);
+
+  if (FT_HAS_KERNING(font->face)) {
+    /* Create kerning cache table and fill with value indicating "unset". */
+    font->kerning_cache = MEM_mallocN(sizeof(KerningCacheBLF), __func__);
+    for (uint i = 0; i < KERNING_CACHE_TABLE_SIZE; i++) {
+      for (uint j = 0; j < KERNING_CACHE_TABLE_SIZE; j++) {
+        font->kerning_cache->ascii_table[i][j] = KERNING_ENTRY_UNSET;
+      }
+    }
+  }
+
   return font;
 }
 
@@ -1346,54 +1416,61 @@ FontBLF *blf_font_new_from_mem(const char *name, const unsigned char *mem, int m
   return font;
 }
 
-int blf_font_height_max(FontBLF *font)
+void blf_font_free(FontBLF *font)
 {
-  int height_max;
-
-  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  height_max = gc->glyph_height_max;
+  BLI_spin_lock(&blf_glyph_cache_mutex);
+  GlyphCacheBLF *gc;
 
-  blf_glyph_cache_release(font);
-  return height_max;
-}
+  while ((gc = BLI_pophead(&font->cache))) {
+    blf_glyph_cache_free(gc);
+  }
 
-int blf_font_width_max(FontBLF *font)
-{
-  int width_max;
+  if (font->kerning_cache) {
+    MEM_freeN(font->kerning_cache);
+  }
 
-  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  width_max = gc->glyph_width_max;
+  FT_Done_Face(font->face);
+  if (font->filename) {
+    MEM_freeN(font->filename);
+  }
+  if (font->name) {
+    MEM_freeN(font->name);
+  }
+  MEM_freeN(font);
 
-  blf_glyph_cache_release(font);
-  return width_max;
+  BLI_spin_unlock(&blf_glyph_cache_mutex);
 }
 
-float blf_font_descender(FontBLF *font)
-{
-  float descender;
-
-  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  descender = gc->descender;
+/** \} */
 
-  blf_glyph_cache_release(font);
-  return descender;
-}
+/* -------------------------------------------------------------------- */
+/** \name Font Configure
+ * \{ */
 
-float blf_font_ascender(FontBLF *font)
+void blf_font_size(FontBLF *font, unsigned int size, unsigned int dpi)
 {
-  float ascender;
+  blf_glyph_cache_acquire(font);
 
-  GlyphCacheBLF *gc = blf_glyph_cache_acquire(font);
-  ascender = gc->ascender;
+  GlyphCacheBLF *gc = blf_glyph_cache_find(font, size, dpi);
+  if (gc && (font->size == size && font->dpi == dpi)) {
+    /* Optimization: do not call FT_Set_Char_Size if size did not change. */
+  }
+  else {
+    const FT_Error err = FT_Set_Char_Size(font->face, 0, ((FT_F26Dot6)(size)) * 64, dpi, dpi);
+    if (err) {
+      /* FIXME: here we can go through the fixed size and choice a close one */
+      printf("The current font don't support the size, %u and dpi, %u\n", size, dpi);
+    }
+    else {
+      font->size = size;
+      font->dpi = dpi;
+      if (gc == NULL) {
+        blf_glyph_cache_new(font);
+      }
+    }
+  }
 
   blf_glyph_cache_release(font);
-  return ascender;
 }
 
-char *blf_display_name(FontBLF *font)
-{
-  if (!font->face->family_name) {
-    return NULL;
-  }
-  return BLI_sprintfN("%s %s", font->face->family_name, font->face->style_name);
-}
+/** \} */
diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index 5fb69251466..6cdf5fc5996 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -55,56 +55,6 @@
 #include "BLI_math_vector.h"
 #include "BLI_strict_flags.h"
 
-KerningCacheBLF *blf_kerning_cache_find(FontBLF *font)
-{
-  return (KerningCacheBLF *)font->kerning_caches.first;
-}
-
-/* Create a new glyph cache for the current kerning mode. */
-KerningCacheBLF *blf_kerning_cache_new(FontBLF *font, GlyphCacheBLF *gc)
-{
-  KerningCacheBLF *kc = MEM_mallocN(sizeof(KerningCacheBLF), __func__);
-  kc->next = NULL;
-  kc->prev = NULL;
-
-  GlyphBLF *g_table[KERNING_CACHE_TABLE_SIZE];
-  for (uint i = 0; i < KERNING_CACHE_TABLE_SIZE; i++) {
-    GlyphBLF *g = blf_glyph_search(gc, i);
-    if (UNLIKELY(g == NULL)) {
-      FT_UInt glyph_index = FT_Get_Char_Index(font->face, i);
-      g = blf_glyph_add(font, gc, glyph_index, i);
-    }
-    g_table[i] = g;
-  }
-
-  memset(kc->ascii_table, 0, sizeof(kc->ascii_table));
-  for (uint i = 0; i < KERNING_CACHE_TABLE_SIZE; i++) {
-    GlyphBLF *g = g_table[i];
-    if (g == NULL) {
-      continue;
-    }
-    for (uint j = 0; j < KERNING_CACHE_TABLE_SIZE; j++) {
-      GlyphBLF *g_prev = g_table[j];
-      if (g_prev == NULL) {
-        continue;
-      }
-      FT_Vector delta;
-      if (FT_Get_Kerning(font->face, g_prev->idx, g->idx, FT_KERNING_DEFAULT, &delta) == 0) {
-        kc->ascii_table[i][j] = (int)delta.x >> 6;
-      }
-    }
-  }
-
-  BLI_addhead(&font->kerning_caches, kc);
-  return kc;
-}
-
-void blf_kerning_cache_clear(FontBLF *font)
-{
-  font->kerning_cache = NULL;
-  BLI_freelistN(&font->kerning_caches);
-}
-
 GlyphCacheBLF *blf_glyph_cache_find(FontBLF *font, unsigned int size, unsigned int dpi)
 {
   GlyphCacheBLF *p;
diff --git a/source/blender/blenfont/intern/blf_internal.h b/source/blender/blenfont/intern/blf_internal.h
index 35a6d019eac..ab2a26b1e06 100644
--- a/source/blender/blenfont/intern/blf_internal.h
+++ b/source/blender/blenfont/intern/blf_internal.h
@@ -121,10 +121,6 @@ int blf_font_count_missing_chars(struct FontBLF *font,
 
 void blf_font_free(struct FontBLF *font);
 
-struct KerningCacheBLF *blf_kerning_cache_find(struct FontBLF *font);
-struct KerningCacheBLF *blf_kerning_cache_new(struct FontBLF *font, struct GlyphCacheBLF *gc);
-void blf_kerning_cache_clear(struct FontBLF *font);
-
 struct GlyphCacheBLF *blf_glyph_cache_find(struct FontBLF *font,
                                            unsigned int size,
                                            unsigned int dpi);
diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h
index caa10b2b125..38d7d7b6e21 100644
--- a/source/blender/blenfont/intern/blf_internal_types.h
+++ b/source/blender/blenfont/intern/blf_internal_types.h
@@ -34,6 +34,9 @@
 /* Number of characters in KerningCacheBLF.table. */
 #define KERNING_CACHE_TABLE_SIZE 128
 
+/* A value in the kerning cache that indicates it is not yet set. */
+#define KERNING_ENTRY_UNSET INT_MAX
+
 typedef struct BatchBLF {
   struct FontBLF *font; /* can only batch glyph from the same font */
   struct GPUBatch *batch;
@@ -50,7 +53,6 @@ typedef struct BatchBLF {
 extern BatchBLF g_batch;
 
 typedef struct KerningCacheBLF {
-  struct KerningCacheBLF *next, *prev;
   /**
    * Cache a ascii glyph pairs. Only store the x offset we are interested in,
    * instead of the full #FT_Vector since it's not used for drawing at the moment.
@@ -223,10 +225,7 @@ typedef struct FontBLF {
    */
   ListBase cache;
 
-  /* list of kerning cache for this font. */
-  ListBase kerning_caches;
-
-  /* current kerning cache for this font and kerning mode. */
+  /* Cache of unscaled kerning values. Will be NULL if font does not have kerning. */
   KerningCacheBLF *kerning_cache;
 
   /* freetype2 lib handle. */
diff --git a/source/blender/blenkernel/BKE_cachefile.h b/source/blender/blenkernel/BKE_cachefile.h
index 58d876b184b..836597f95da 100644
--- a/source/blender/blenkernel/BKE_cachefile.h
+++ b/source/blender/blenkernel/BKE_cachefile.h
@@ -61,11 +61,6 @@ void BKE_cachefile_reader_open(struct CacheFile *cache_file,
                                const char *object_path);
 void BKE_cachefile_reader_free(struct CacheFile *cache_file, struct CacheReader **reader);
 
-/* Determine whether the CacheFile should use a render engine procedural. If so, data is not read
- * from the file and bouding boxes are used to represent the objects in the Scene. Render engines
- * will receive the bounding box as a placeholder but can instead load the data directly if they
- * support it.
- */
 bool BKE_cache_file_uses_render_procedural(const struct CacheFile *cache_file,
                                            struct Scene *scene,
                                            const int dag_eval_mode);
diff --git a/source/blender/blenkernel/intern/cachefile.c b/source/blender/blenkernel/intern/cachefile.c
index 4a60564b4a1..87b1584d422 100644
--- a/source/blender/blenkernel/intern/cachefile.c
+++ b/source/blender/blenkernel/intern/cachefile.c
@@ -368,7 +368,7 @@ void BKE_cachefile_eval(Main *bmain, Depsgraph *depsgraph, CacheFile *cache_file
 #endif
 
   if (DEG_is_active(depsgraph)) {
-    /* Flush object paths back to original datablock for UI. */
+    /* Flush object paths back to original data-block for UI. */
     CacheFile *cache_file_orig = (CacheFile *)DEG_get_original_id(&cache_file->id);
     BLI_freelistN(&cache_file_orig->object_paths);
     BLI_duplicatelist(&cache_file_orig->object_paths, &cache_file->object_paths);
@@ -411,6 +411,12 @@ float BKE_cachefile_time_offset(const CacheFile *cache_file, const float time, c
   return cache_file->is_sequence ? frame : frame / fps - time_offset;
 }
 
+/**
+ * Determine whether the #CacheFile should use a render engine procedural. If so, data is not read
+ * from the file and bounding boxes are used to represent the objects in the Scene.
+ * Render engines will receive the bounding box as a placeholder but can instead
+ * load the data directly if they support it.
+ */
 bool BKE_cache_file_uses_render_procedural(const CacheFile *cache_file,
                                            Scene *scene,
                                            const int dag_eval_mode)
diff --git a/source/blender/blenlib/BLI_fileops.h b/source/blender/blenlib/BLI_fileops.h
index 7cfecc798a7..906a56ce909 100644
--- a/source/blender/blenlib/BLI_fileops.h
+++ b/source/blender/blenlib/BLI_fileops.h
@@ -154,18 +154,17 @@ bool BLI_file_is_writable(const char *file) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL
 bool BLI_file_touch(const char *file) ATTR_NONNULL();
 bool BLI_file_alias_target(const char *filepath, char *r_targetpath) ATTR_WARN_UNUSED_RESULT;
 
-#if 0 /* UNUSED */
-int BLI_file_gzip(const char *from, const char *to) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
-#endif
-char *BLI_file_ungzip_to_mem(const char *from_file, int *r_size) ATTR_WARN_UNUSED_RESULT
-    ATTR_NONNULL();
-size_t BLI_gzip_mem_to_file_at_pos(void *buf,
-                                   size_t len,
-                                   FILE *file,
-                                   size_t gz_stream_offset,
-                                   int compression_level) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
-size_t BLI_ungzip_file_to_mem_at_pos(void *buf, size_t len, FILE *file, size_t gz_stream_offset)
+bool BLI_file_magic_is_gzip(const char header[4]);
+
+size_t BLI_file_zstd_from_mem_at_pos(void *buf,
+                                     size_t len,
+                                     FILE *file,
+                                     size_t file_offset,
+                                     int compression_level) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
+size_t BLI_file_unzstd_to_mem_at_pos(void *buf, size_t len, FILE *file, size_t file_offset)
     ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
+bool BLI_file_magic_is_zstd(const char header[4]);
+
 size_t BLI_file_descriptor_size(int file) ATTR_WARN_UNUSED_RESULT;
 size_t BLI_file_size(const char *path) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 
diff --git a/source/blender/blenlib/BLI_filereader.h b/source/blender/blenlib/BLI_filereader.h
new file mode 100644
index 00000000000..8d1fa3d1596
--- /dev/null
+++ b/source/blender/blenlib/BLI_filereader.h
@@ -0,0 +1,81 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bli
+ * \brief Wrapper for reading from various sources (e.g. raw files, compressed files, memory...).
+ */
+
+#pragma once
+
+#ifdef WIN32
+#  include "BLI_winstuff.h"
+#else
+#  include <sys/types.h>
+#endif
+
+#include "BLI_compiler_attrs.h"
+#include "BLI_utildefines.h"
+
+#if defined(_MSC_VER) || defined(__APPLE__) || defined(__HAIKU__) || defined(__NetBSD__)
+typedef int64_t off64_t;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct FileReader;
+
+typedef ssize_t (*FileReaderReadFn)(struct FileReader *reader, void *buffer, size_t size);
+typedef off64_t (*FileReaderSeekFn)(struct FileReader *reader, off64_t offset, int whence);
+typedef void (*FileReaderCloseFn)(struct FileReader *reader);
+
+/* General structure for all FileReaders, implementations add custom fields at the end. */
+typedef struct FileReader {
+  FileReaderReadFn read;
+  FileReaderSeekFn seek;
+  FileReaderCloseFn close;
+
+  off64_t offset;
+} FileReader;
+
+/* Functions for opening the various types of FileReader.
+ * They either succeed and return a valid FileReader, or fail and return NULL.
+ *
+ * If a FileReader is created, it has to be cleaned up and freed by calling
+ * its close() function unless another FileReader has taken ownership - for example,
+ * Zstd and Gzip take over the base FileReader and will clean it up when their clean() is called.
+ */
+
+/* Create FileReader from raw file descriptor. */
+FileReader *BLI_filereader_new_file(int filedes) ATTR_WARN_UNUSED_RESULT;
+/* Create FileReader from raw file descriptor using memory-mapped IO. */
+FileReader *BLI_filereader_new_mmap(int filedes) ATTR_WARN_UNUSED_RESULT;
+/* Create FileReader from a region of memory. */
+FileReader *BLI_filereader_new_memory(const void *data, size_t len) ATTR_WARN_UNUSED_RESULT
+    ATTR_NONNULL();
+/* Create FileReader from applying Zstd decompression on an underlying file. */
+FileReader *BLI_filereader_new_zstd(FileReader *base) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
+/* Create FileReader from applying Gzip decompression on an underlying file. */
+FileReader *BLI_filereader_new_gzip(FileReader *base) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/source/blender/blenlib/CMakeLists.txt b/source/blender/blenlib/CMakeLists.txt
index b6603dce378..f98d15ad08b 100644
--- a/source/blender/blenlib/CMakeLists.txt
+++ b/source/blender/blenlib/CMakeLists.txt
@@ -31,6 +31,7 @@ set(INC
 
 set(INC_SYS
   ${ZLIB_INCLUDE_DIRS}
+  ${ZSTD_INCLUDE_DIRS}
   ${FREETYPE_INCLUDE_DIRS}
   ${GMP_INCLUDE_DIRS}
 )
@@ -75,6 +76,10 @@ set(SRC
   intern/endian_switch.c
   intern/expr_pylike_eval.c
   intern/fileops.c
+  intern/filereader_file.c
+  intern/filereader_gzip.c
+  intern/filereader_memory.c
+  intern/filereader_zstd.c
   intern/fnmatch.c
   intern/freetypefont.c
   intern/gsqueue.c
@@ -194,6 +199,7 @@ set(SRC
   BLI_enumerable_thread_specific.hh
   BLI_expr_pylike_eval.h
   BLI_fileops.h
+  BLI_filereader.h
   BLI_fileops_types.h
   BLI_float2.hh
   BLI_float3.hh
@@ -323,6 +329,7 @@ set(LIB
 
   ${FREETYPE_LIBRARY}
   ${ZLIB_LIBRARIES}
+  ${ZSTD_LIBRARIES}
 )
 
 if(WITH_MEM_VALGRIND)
diff --git a/source/blender/blenlib/intern/fileops.c b/source/blender/blenlib/intern/fileops.c
index ac034d2b5cd..532a29b8147 100644
--- a/source/blender/blenlib/intern/fileops.c
+++ b/source/blender/blenlib/intern/fileops.c
@@ -31,6 +31,7 @@
 #include <errno.h>
 
 #include "zlib.h"
+#include "zstd.h"
 
 #ifdef WIN32
 #  include "BLI_fileops_types.h"
@@ -61,200 +62,124 @@
 #include "BLI_sys_types.h" /* for intptr_t support */
 #include "BLI_utildefines.h"
 
-#if 0 /* UNUSED */
-/* gzip the file in from and write it to "to".
- * return -1 if zlib fails, -2 if the originating file does not exist
- * NOTE: will remove the "from" file
- */
-int BLI_file_gzip(const char *from, const char *to)
+size_t BLI_file_zstd_from_mem_at_pos(
+    void *buf, size_t len, FILE *file, size_t file_offset, int compression_level)
 {
-  char buffer[10240];
-  int file;
-  int readsize = 0;
-  int rval = 0, err;
-  gzFile gzfile;
+  fseek(file, file_offset, SEEK_SET);
 
-  /* level 1 is very close to 3 (the default) in terms of file size,
-   * but about twice as fast, best use for speedy saving - campbell */
-  gzfile = BLI_gzopen(to, "wb1");
-  if (gzfile == NULL) {
-    return -1;
-  }
-  file = BLI_open(from, O_BINARY | O_RDONLY, 0);
-  if (file == -1) {
-    return -2;
-  }
+  ZSTD_CCtx *ctx = ZSTD_createCCtx();
+  ZSTD_CCtx_setParameter(ctx, ZSTD_c_compressionLevel, compression_level);
+
+  ZSTD_inBuffer input = {buf, len, 0};
 
-  while (1) {
-    readsize = read(file, buffer, sizeof(buffer));
+  size_t out_len = ZSTD_CStreamOutSize();
+  void *out_buf = MEM_mallocN(out_len, __func__);
+  size_t total_written = 0;
 
-    if (readsize < 0) {
-      rval = -2; /* error happened in reading */
-      fprintf(stderr, "Error reading file %s: %s.\n", from, strerror(errno));
+  /* Compress block and write it out until the input has been consumed. */
+  while (input.pos < input.size) {
+    ZSTD_outBuffer output = {out_buf, out_len, 0};
+    size_t ret = ZSTD_compressStream2(ctx, &output, &input, ZSTD_e_continue);
+    if (ZSTD_isError(ret)) {
       break;
     }
-    else if (readsize == 0) {
-      break; /* done reading */
+    if (fwrite(out_buf, 1, output.pos, file) != output.pos) {
+      break;
     }
+    total_written += output.pos;
+  }
 
-    if (gzwrite(gzfile, buffer, readsize) <= 0) {
-      rval = -1; /* error happened in writing */
-      fprintf(stderr, "Error writing gz file %s: %s.\n", to, gzerror(gzfile, &err));
+  /* Finalize the Zstd frame. */
+  size_t ret = 1;
+  while (ret != 0) {
+    ZSTD_outBuffer output = {out_buf, out_len, 0};
+    ret = ZSTD_compressStream2(ctx, &output, &input, ZSTD_e_end);
+    if (ZSTD_isError(ret)) {
+      break;
+    }
+    if (fwrite(out_buf, 1, output.pos, file) != output.pos) {
       break;
     }
+    total_written += output.pos;
   }
 
-  gzclose(gzfile);
-  close(file);
+  MEM_freeN(out_buf);
+  ZSTD_freeCCtx(ctx);
 
-  return rval;
+  return ZSTD_isError(ret) ? 0 : total_written;
 }
-#endif
 
-/* gzip the file in from_file and write it to memory to_mem, at most size bytes.
- * return the unzipped size
- */
-char *BLI_file_ungzip_to_mem(const char *from_file, int *r_size)
+size_t BLI_file_unzstd_to_mem_at_pos(void *buf, size_t len, FILE *file, size_t file_offset)
 {
-  gzFile gzfile;
-  int readsize, size, alloc_size = 0;
-  char *mem = NULL;
-  const int chunk_size = 512 * 1024;
+  fseek(file, file_offset, SEEK_SET);
 
-  size = 0;
+  ZSTD_DCtx *ctx = ZSTD_createDCtx();
 
-  gzfile = BLI_gzopen(from_file, "rb");
-  for (;;) {
-    if (mem == NULL) {
-      mem = MEM_callocN(chunk_size, "BLI_ungzip_to_mem");
-      alloc_size = chunk_size;
-    }
-    else {
-      mem = MEM_reallocN(mem, size + chunk_size);
-      alloc_size += chunk_size;
-    }
+  size_t in_len = ZSTD_DStreamInSize();
+  void *in_buf = MEM_mallocN(in_len, __func__);
+  ZSTD_inBuffer input = {in_buf, in_len, 0};
 
-    readsize = gzread(gzfile, mem + size, chunk_size);
-    if (readsize > 0) {
-      size += readsize;
-    }
-    else {
+  ZSTD_outBuffer output = {buf, len, 0};
+
+  size_t ret = 0;
+  /* Read and decompress chunks of input data until we have enough output. */
+  while (output.pos < output.size && !ZSTD_isError(ret)) {
+    input.size = fread(in_buf, 1, in_len, file);
+    if (input.size == 0) {
       break;
     }
-  }
 
-  gzclose(gzfile);
+    /* Consume input data until we run out or have enough output. */
+    input.pos = 0;
+    while (input.pos < input.size && output.pos < output.size) {
+      ret = ZSTD_decompressStream(ctx, &output, &input);
 
-  if (size == 0) {
-    MEM_freeN(mem);
-    mem = NULL;
-  }
-  else if (alloc_size != size) {
-    mem = MEM_reallocN(mem, size);
+      if (ZSTD_isError(ret)) {
+        break;
+      }
+    }
   }
 
-  *r_size = size;
+  MEM_freeN(in_buf);
+  ZSTD_freeDCtx(ctx);
 
-  return mem;
+  return ZSTD_isError(ret) ? 0 : output.pos;
 }
 
-#define CHUNK (256 * 1024)
-
-/* gzip byte array from memory and write it to file at certain position.
- * return size of gzip stream.
- */
-size_t BLI_gzip_mem_to_file_at_pos(
-    void *buf, size_t len, FILE *file, size_t gz_stream_offset, int compression_level)
+bool BLI_file_magic_is_gzip(const char header[4])
 {
-  int ret, flush;
-  unsigned have;
-  z_stream strm;
-  unsigned char out[CHUNK];
-
-  BLI_fseek(file, gz_stream_offset, 0);
-
-  strm.zalloc = Z_NULL;
-  strm.zfree = Z_NULL;
-  strm.opaque = Z_NULL;
-  ret = deflateInit(&strm, compression_level);
-  if (ret != Z_OK) {
-    return 0;
-  }
-
-  strm.avail_in = len;
-  strm.next_in = (Bytef *)buf;
-  flush = Z_FINISH;
-
-  do {
-    strm.avail_out = CHUNK;
-    strm.next_out = out;
-    ret = deflate(&strm, flush);
-    if (ret == Z_STREAM_ERROR) {
-      return 0;
-    }
-    have = CHUNK - strm.avail_out;
-    if (fwrite(out, 1, have, file) != have || ferror(file)) {
-      deflateEnd(&strm);
-      return 0;
-    }
-  } while (strm.avail_out == 0);
-
-  if (strm.avail_in != 0 || ret != Z_STREAM_END) {
-    return 0;
-  }
-
-  deflateEnd(&strm);
-  return (size_t)strm.total_out;
+  /* GZIP itself starts with the magic bytes 0x1f 0x8b.
+   * The third byte indicates the compression method, which is 0x08 for DEFLATE. */
+  return header[0] == 0x1f && header[1] == 0x8b && header[2] == 0x08;
 }
 
-/* read and decompress gzip stream from file at certain position to buffer.
- * return size of decompressed data.
- */
-size_t BLI_ungzip_file_to_mem_at_pos(void *buf, size_t len, FILE *file, size_t gz_stream_offset)
+bool BLI_file_magic_is_zstd(const char header[4])
 {
-  int ret;
-  z_stream strm;
-  size_t chunk = 256 * 1024;
-  unsigned char in[CHUNK];
-
-  BLI_fseek(file, gz_stream_offset, 0);
-
-  strm.zalloc = Z_NULL;
-  strm.zfree = Z_NULL;
-  strm.opaque = Z_NULL;
-  strm.avail_in = 0;
-  strm.next_in = Z_NULL;
-  ret = inflateInit(&strm);
-  if (ret != Z_OK) {
-    return 0;
+  /* ZSTD files consist of concatenated frames, each either a Zstd frame or a skippable frame.
+   * Both types of frames start with a magic number: 0xFD2FB528 for Zstd frames and 0x184D2A5*
+   * for skippable frames, with the * being anything from 0 to F.
+   *
+   * To check whether a file is Zstd-compressed, we just check whether the first frame matches
+   * either. Seeking through the file until a Zstd frame is found would make things more
+   * complicated and the probability of a false positive is rather low anyways.
+   *
+   * Note that LZ4 uses a compatible format, so even though its compressed frames have a
+   * different magic number, a valid LZ4 file might also start with a skippable frame matching
+   * the second check here.
+   *
+   * For more details, see https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md
+   */
+
+  uint32_t magic = *((uint32_t *)header);
+  if (magic == 0xFD2FB528) {
+    return true;
   }
-
-  do {
-    strm.avail_in = fread(in, 1, chunk, file);
-    strm.next_in = in;
-    if (ferror(file)) {
-      inflateEnd(&strm);
-      return 0;
-    }
-
-    do {
-      strm.avail_out = len;
-      strm.next_out = (Bytef *)buf + strm.total_out;
-
-      ret = inflate(&strm, Z_NO_FLUSH);
-      if (ret == Z_STREAM_ERROR) {
-        return 0;
-      }
-    } while (strm.avail_out == 0);
-
-  } while (ret != Z_STREAM_END);
-
-  inflateEnd(&strm);
-  return (size_t)strm.total_out;
+  if ((magic >> 4) == 0x184D2A5) {
+    return true;
+  }
+  return false;
 }
 
-#undef CHUNK
-
 /**
  * Returns true if the file with the specified name can be written.
  * This implementation uses access(2), which makes the check according
diff --git a/source/blender/blenlib/intern/filereader_file.c b/source/blender/blenlib/intern/filereader_file.c
new file mode 100644
index 00000000000..3a833871e27
--- /dev/null
+++ b/source/blender/blenlib/intern/filereader_file.c
@@ -0,0 +1,80 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2004-2021 Blender Foundation
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bli
+ */
+
+#ifndef WIN32
+#  include <unistd.h> /* for read close */
+#else
+#  include "BLI_winstuff.h"
+#  include "winsock2.h"
+#  include <io.h> /* for open close read */
+#endif
+
+#include "BLI_blenlib.h"
+#include "BLI_filereader.h"
+
+#include "MEM_guardedalloc.h"
+
+typedef struct {
+  FileReader reader;
+
+  int filedes;
+} RawFileReader;
+
+static ssize_t file_read(FileReader *reader, void *buffer, size_t size)
+{
+  RawFileReader *rawfile = (RawFileReader *)reader;
+  ssize_t readsize = read(rawfile->filedes, buffer, size);
+
+  if (readsize >= 0) {
+    rawfile->reader.offset += readsize;
+  }
+
+  return readsize;
+}
+
+static off64_t file_seek(FileReader *reader, off64_t offset, int whence)
+{
+  RawFileReader *rawfile = (RawFileReader *)reader;
+  rawfile->reader.offset = BLI_lseek(rawfile->filedes, offset, whence);
+  return rawfile->reader.offset;
+}
+
+static void file_close(FileReader *reader)
+{
+  RawFileReader *rawfile = (RawFileReader *)reader;
+  close(rawfile->filedes);
+  MEM_freeN(rawfile);
+}
+
+FileReader *BLI_filereader_new_file(int filedes)
+{
+  RawFileReader *rawfile = MEM_callocN(sizeof(RawFileReader), __func__);
+
+  rawfile->filedes = filedes;
+
+  rawfile->reader.read = file_read;
+  rawfile->reader.seek = file_seek;
+  rawfile->reader.close = file_close;
+
+  return (FileReader *)rawfile;
+}
diff --git a/source/blender/blenlib/intern/filereader_gzip.c b/source/blender/blenlib/intern/filereader_gzip.c
new file mode 100644
index 00000000000..72eb153a8b9
--- /dev/null
+++ b/source/blender/blenlib/intern/filereader_gzip.c
@@ -0,0 +1,108 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2004-2021 Blender Foundation
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bli
+ */
+
+#include <zlib.h>
+
+#include "BLI_blenlib.h"
+#include "BLI_filereader.h"
+
+#include "MEM_guardedalloc.h"
+
+typedef struct {
+  FileReader reader;
+
+  FileReader *base;
+
+  z_stream strm;
+
+  void *in_buf;
+  size_t in_size;
+} GzipReader;
+
+static ssize_t gzip_read(FileReader *reader, void *buffer, size_t size)
+{
+  GzipReader *gzip = (GzipReader *)reader;
+
+  gzip->strm.avail_out = size;
+  gzip->strm.next_out = buffer;
+
+  while (gzip->strm.avail_out > 0) {
+    if (gzip->strm.avail_in == 0) {
+      /* Ran out of buffered input data, read some more. */
+      size_t readsize = gzip->base->read(gzip->base, gzip->in_buf, gzip->in_size);
+
+      if (readsize > 0) {
+        /* We got some data, so mark the buffer as refilled. */
+        gzip->strm.avail_in = readsize;
+        gzip->strm.next_in = gzip->in_buf;
+      }
+      else {
+        /* The underlying file is EOF, so return as much as we can. */
+        break;
+      }
+    }
+
+    int ret = inflate(&gzip->strm, Z_NO_FLUSH);
+
+    if (ret != Z_OK && ret != Z_BUF_ERROR) {
+      break;
+    }
+  }
+
+  ssize_t read_len = size - gzip->strm.avail_out;
+  gzip->reader.offset += read_len;
+  return read_len;
+}
+
+static void gzip_close(FileReader *reader)
+{
+  GzipReader *gzip = (GzipReader *)reader;
+
+  if (inflateEnd(&gzip->strm) != Z_OK) {
+    printf("close gzip stream error\n");
+  }
+  MEM_freeN((void *)gzip->in_buf);
+
+  gzip->base->close(gzip->base);
+  MEM_freeN(gzip);
+}
+
+FileReader *BLI_filereader_new_gzip(FileReader *base)
+{
+  GzipReader *gzip = MEM_callocN(sizeof(GzipReader), __func__);
+  gzip->base = base;
+
+  if (inflateInit2(&gzip->strm, 16 + MAX_WBITS) != Z_OK) {
+    MEM_freeN(gzip);
+    return NULL;
+  }
+
+  gzip->in_size = 256 * 2014;
+  gzip->in_buf = MEM_mallocN(gzip->in_size, "gzip in buf");
+
+  gzip->reader.read = gzip_read;
+  gzip->reader.seek = NULL;
+  gzip->reader.close = gzip_close;
+
+  return (FileReader *)gzip;
+}
diff --git a/source/blender/blenlib/intern/filereader_memory.c b/source/blender/blenlib/intern/filereader_memory.c
new file mode 100644
index 00000000000..150fed7d1cc
--- /dev/null
+++ b/source/blender/blenlib/intern/filereader_memory.c
@@ -0,0 +1,145 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2004-2021 Blender Foundation
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bli
+ */
+
+#include <string.h>
+
+#include "BLI_blenlib.h"
+#include "BLI_filereader.h"
+#include "BLI_mmap.h"
+
+#include "MEM_guardedalloc.h"
+
+/* This file implements both memory-backed and memory-mapped-file-backed reading. */
+typedef struct {
+  FileReader reader;
+
+  const char *data;
+  BLI_mmap_file *mmap;
+  size_t length;
+} MemoryReader;
+
+static ssize_t memory_read_raw(FileReader *reader, void *buffer, size_t size)
+{
+  MemoryReader *mem = (MemoryReader *)reader;
+
+  /* Don't read more bytes than there are available in the buffer. */
+  size_t readsize = MIN2(size, (size_t)(mem->length - mem->reader.offset));
+
+  memcpy(buffer, mem->data + mem->reader.offset, readsize);
+  mem->reader.offset += readsize;
+
+  return readsize;
+}
+
+static off64_t memory_seek(FileReader *reader, off64_t offset, int whence)
+{
+  MemoryReader *mem = (MemoryReader *)reader;
+
+  off64_t new_pos;
+  if (whence == SEEK_CUR) {
+    new_pos = mem->reader.offset + offset;
+  }
+  else if (whence == SEEK_SET) {
+    new_pos = offset;
+  }
+  else if (whence == SEEK_END) {
+    new_pos = mem->length + offset;
+  }
+  else {
+    return -1;
+  }
+
+  if (new_pos < 0 || new_pos > mem->length) {
+    return -1;
+  }
+
+  mem->reader.offset = new_pos;
+  return mem->reader.offset;
+}
+
+static void memory_close_raw(FileReader *reader)
+{
+  MEM_freeN(reader);
+}
+
+FileReader *BLI_filereader_new_memory(const void *data, size_t len)
+{
+  MemoryReader *mem = MEM_callocN(sizeof(MemoryReader), __func__);
+
+  mem->data = (const char *)data;
+  mem->length = len;
+
+  mem->reader.read = memory_read_raw;
+  mem->reader.seek = memory_seek;
+  mem->reader.close = memory_close_raw;
+
+  return (FileReader *)mem;
+}
+
+/* Memory-mapped file reading.
+ * By using `mmap()`, we can map a file so that it can be treated like normal memory,
+ * meaning that we can just read from it with `memcpy()` etc.
+ * This avoids system call overhead and can significantly speed up file loading.
+ */
+
+static ssize_t memory_read_mmap(FileReader *reader, void *buffer, size_t size)
+{
+  MemoryReader *mem = (MemoryReader *)reader;
+
+  /* Don't read more bytes than there are available in the buffer. */
+  size_t readsize = MIN2(size, (size_t)(mem->length - mem->reader.offset));
+
+  if (!BLI_mmap_read(mem->mmap, buffer, mem->reader.offset, readsize)) {
+    return 0;
+  }
+
+  mem->reader.offset += readsize;
+
+  return readsize;
+}
+
+static void memory_close_mmap(FileReader *reader)
+{
+  MemoryReader *mem = (MemoryReader *)reader;
+  BLI_mmap_free(mem->mmap);
+  MEM_freeN(mem);
+}
+
+FileReader *BLI_filereader_new_mmap(int filedes)
+{
+  BLI_mmap_file *mmap = BLI_mmap_open(filedes);
+  if (mmap == NULL) {
+    return NULL;
+  }
+
+  MemoryReader *mem = MEM_callocN(sizeof(MemoryReader), __func__);
+
+  mem->mmap = mmap;
+  mem->length = BLI_lseek(filedes, 0, SEEK_END);
+
+  mem->reader.read = memory_read_mmap;
+  mem->reader.seek = memory_seek;
+  mem->reader.close = memory_close_mmap;
+
+  return (FileReader *)mem;
+}
diff --git a/source/blender/blenlib/intern/filereader_zstd.c b/source/blender/blenlib/intern/filereader_zstd.c
new file mode 100644
index 00000000000..785a40cd1a1
--- /dev/null
+++ b/source/blender/blenlib/intern/filereader_zstd.c
@@ -0,0 +1,335 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2021 Blender Foundation
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup bli
+ */
+
+#include <string.h>
+#include <zstd.h>
+
+#include "BLI_blenlib.h"
+#include "BLI_endian_switch.h"
+#include "BLI_filereader.h"
+#include "BLI_math_base.h"
+
+#include "MEM_guardedalloc.h"
+
+typedef struct {
+  FileReader reader;
+
+  FileReader *base;
+
+  ZSTD_DCtx *ctx;
+  ZSTD_inBuffer in_buf;
+  size_t in_buf_max_size;
+
+  struct {
+    int num_frames;
+    size_t *compressed_ofs;
+    size_t *uncompressed_ofs;
+
+    char *cached_content;
+    int cached_frame;
+  } seek;
+} ZstdReader;
+
+static bool zstd_read_u32(FileReader *base, uint32_t *val)
+{
+  if (base->read(base, val, sizeof(uint32_t)) != sizeof(uint32_t)) {
+    return false;
+  }
+#ifdef __BIG_ENDIAN__
+  BLI_endian_switch_uint32(val);
+#endif
+  return true;
+}
+
+static bool zstd_read_seek_table(ZstdReader *zstd)
+{
+  FileReader *base = zstd->base;
+
+  /* The seek table frame is at the end of the file, so seek there
+   * and verify that there is enough data. */
+  if (base->seek(base, -4, SEEK_END) < 13) {
+    return false;
+  }
+  uint32_t magic;
+  if (!zstd_read_u32(base, &magic) || magic != 0x8F92EAB1) {
+    return false;
+  }
+
+  uint8_t flags;
+  if (base->seek(base, -5, SEEK_END) < 0 || base->read(base, &flags, 1) != 1) {
+    return false;
+  }
+  /* Bit 7 indicates checksums. Bits 5 and 6 must be zero. */
+  bool has_checksums = (flags & 0x80);
+  if (flags & 0x60) {
+    return false;
+  }
+
+  uint32_t num_frames;
+  if (base->seek(base, -9, SEEK_END) < 0 || !zstd_read_u32(base, &num_frames)) {
+    return false;
+  }
+
+  /* Each frame has either 2 or 3 uint32_t, and after that we have
+   * num_frames, flags and magic for another 9 bytes. */
+  uint32_t expected_frame_length = num_frames * (has_checksums ? 12 : 8) + 9;
+  /* The frame starts with another magic number and its length, but these
+   * two fields are not included when counting length. */
+  off64_t frame_start_ofs = 8 + expected_frame_length;
+  /* Sanity check: Before the start of the seek table frame,
+   * there must be num_frames frames, each of which at least 8 bytes long. */
+  off64_t seek_frame_start = base->seek(base, -frame_start_ofs, SEEK_END);
+  if (seek_frame_start < num_frames * 8) {
+    return false;
+  }
+
+  if (!zstd_read_u32(base, &magic) || magic != 0x184D2A5E) {
+    return false;
+  }
+
+  uint32_t frame_length;
+  if (!zstd_read_u32(base, &frame_length) || frame_length != expected_frame_length) {
+    return false;
+  }
+
+  zstd->seek.num_frames = num_frames;
+  zstd->seek.compressed_ofs = MEM_malloc_arrayN(num_frames + 1, sizeof(size_t), __func__);
+  zstd->seek.uncompressed_ofs = MEM_malloc_arrayN(num_frames + 1, sizeof(size_t), __func__);
+
+  size_t compressed_ofs = 0;
+  size_t uncompressed_ofs = 0;
+  for (int i = 0; i < num_frames; i++) {
+    uint32_t compressed_size, uncompressed_size;
+    if (!zstd_read_u32(base, &compressed_size) || !zstd_read_u32(base, &uncompressed_size)) {
+      break;
+    }
+    if (has_checksums && base->seek(base, 4, SEEK_CUR) < 0) {
+      break;
+    }
+    zstd->seek.compressed_ofs[i] = compressed_ofs;
+    zstd->seek.uncompressed_ofs[i] = uncompressed_ofs;
+    compressed_ofs += compressed_size;
+    uncompressed_ofs += uncompressed_size;
+  }
+  zstd->seek.compressed_ofs[num_frames] = compressed_ofs;
+  zstd->seek.uncompressed_ofs[num_frames] = uncompressed_ofs;
+
+  /* Seek to the end of the previous frame for the following BHead frame detection. */
+  if (seek_frame_start != compressed_ofs || base->seek(base, seek_frame_start, SEEK_SET) < 0) {
+    MEM_freeN(zstd->seek.compressed_ofs);
+    MEM_freeN(zstd->seek.uncompressed_ofs);
+    memset(&zstd->seek, 0, sizeof(zstd->seek));
+    return false;
+  }
+
+  zstd->seek.cached_frame = -1;
+
+  return true;
+}
+
+/* Find out which frame contains the given position in the uncompressed stream.
+ * Basically just bisection. */
+static int zstd_frame_from_pos(ZstdReader *zstd, size_t pos)
+{
+  int low = 0, high = zstd->seek.num_frames;
+
+  if (pos >= zstd->seek.uncompressed_ofs[zstd->seek.num_frames]) {
+    return -1;
+  }
+
+  while (low + 1 < high) {
+    int mid = low + ((high - low) >> 1);
+    if (zstd->seek.uncompressed_ofs[mid] <= pos) {
+      low = mid;
+    }
+    else {
+      high = mid;
+    }
+  }
+
+  return low;
+}
+
+/* Ensure that the currently loaded frame is the correct one. */
+static const char *zstd_ensure_cache(ZstdReader *zstd, int frame)
+{
+  if (zstd->seek.cached_frame == frame) {
+    /* Cached frame matches, so just return it. */
+    return zstd->seek.cached_content;
+  }
+
+  /* Cached frame doesn't match, so discard it and cache the wanted one onstead. */
+  MEM_SAFE_FREE(zstd->seek.cached_content);
+
+  size_t compressed_size = zstd->seek.compressed_ofs[frame + 1] - zstd->seek.compressed_ofs[frame];
+  size_t uncompressed_size = zstd->seek.uncompressed_ofs[frame + 1] -
+                             zstd->seek.uncompressed_ofs[frame];
+
+  char *uncompressed_data = MEM_mallocN(uncompressed_size, __func__);
+  char *compressed_data = MEM_mallocN(compressed_size, __func__);
+  if (zstd->base->seek(zstd->base, zstd->seek.compressed_ofs[frame], SEEK_SET) < 0 ||
+      zstd->base->read(zstd->base, compressed_data, compressed_size) < compressed_size) {
+    MEM_freeN(compressed_data);
+    MEM_freeN(uncompressed_data);
+    return NULL;
+  }
+
+  size_t res = ZSTD_decompressDCtx(
+      zstd->ctx, uncompressed_data, uncompressed_size, compressed_data, compressed_size);
+  MEM_freeN(compressed_data);
+  if (ZSTD_isError(res) || res < uncompressed_size) {
+    MEM_freeN(uncompressed_data);
+    return NULL;
+  }
+
+  zstd->seek.cached_frame = frame;
+  zstd->seek.cached_content = uncompressed_data;
+  return uncompressed_data;
+}
+
+static ssize_t zstd_read_seekable(FileReader *reader, void *buffer, size_t size)
+{
+  ZstdReader *zstd = (ZstdReader *)reader;
+
+  size_t end_offset = zstd->reader.offset + size, read_len = 0;
+  while (zstd->reader.offset < end_offset) {
+    int frame = zstd_frame_from_pos(zstd, zstd->reader.offset);
+    if (frame < 0) {
+      /* EOF is reached, so return as much as we can. */
+      break;
+    }
+
+    const char *framedata = zstd_ensure_cache(zstd, frame);
+    if (framedata == NULL) {
+      /* Error while reading the frame, so return as much as we can. */
+      break;
+    }
+
+    size_t frame_end_offset = min_zz(zstd->seek.uncompressed_ofs[frame + 1], end_offset);
+    size_t frame_read_len = frame_end_offset - zstd->reader.offset;
+
+    size_t offset_in_frame = zstd->reader.offset - zstd->seek.uncompressed_ofs[frame];
+    memcpy((char *)buffer + read_len, framedata + offset_in_frame, frame_read_len);
+    read_len += frame_read_len;
+    zstd->reader.offset = frame_end_offset;
+  }
+
+  return read_len;
+}
+
+static off64_t zstd_seek(FileReader *reader, off64_t offset, int whence)
+{
+  ZstdReader *zstd = (ZstdReader *)reader;
+  off64_t new_pos;
+  if (whence == SEEK_SET) {
+    new_pos = offset;
+  }
+  else if (whence == SEEK_END) {
+    new_pos = zstd->seek.uncompressed_ofs[zstd->seek.num_frames] + offset;
+  }
+  else {
+    new_pos = zstd->reader.offset + offset;
+  }
+
+  if (new_pos < 0 || new_pos > zstd->seek.uncompressed_ofs[zstd->seek.num_frames]) {
+    return -1;
+  }
+  zstd->reader.offset = new_pos;
+  return zstd->reader.offset;
+}
+
+static ssize_t zstd_read(FileReader *reader, void *buffer, size_t size)
+{
+  ZstdReader *zstd = (ZstdReader *)reader;
+  ZSTD_outBuffer output = {buffer, size, 0};
+
+  while (output.pos < output.size) {
+    if (zstd->in_buf.pos == zstd->in_buf.size) {
+      /* Ran out of buffered input data, read some more. */
+      zstd->in_buf.pos = 0;
+      ssize_t readsize = zstd->base->read(
+          zstd->base, (char *)zstd->in_buf.src, zstd->in_buf_max_size);
+
+      if (readsize > 0) {
+        /* We got some data, so mark the buffer as refilled. */
+        zstd->in_buf.size = readsize;
+      }
+      else {
+        /* The underlying file is EOF, so return as much as we can. */
+        break;
+      }
+    }
+
+    if (ZSTD_isError(ZSTD_decompressStream(zstd->ctx, &output, &zstd->in_buf))) {
+      break;
+    }
+  }
+
+  zstd->reader.offset += output.pos;
+  return output.pos;
+}
+
+static void zstd_close(FileReader *reader)
+{
+  ZstdReader *zstd = (ZstdReader *)reader;
+
+  ZSTD_freeDCtx(zstd->ctx);
+  if (zstd->reader.seek) {
+    MEM_freeN(zstd->seek.uncompressed_ofs);
+    MEM_freeN(zstd->seek.compressed_ofs);
+    MEM_freeN(zstd->seek.cached_content);
+  }
+  else {
+    MEM_freeN((void *)zstd->in_buf.src);
+  }
+
+  zstd->base->close(zstd->base);
+  MEM_freeN(zstd);
+}
+
+FileReader *BLI_filereader_new_zstd(FileReader *base)
+{
+  ZstdReader *zstd = MEM_callocN(sizeof(ZstdReader), __func__);
+
+  zstd->ctx = ZSTD_createDCtx();
+  zstd->base = base;
+
+  if (zstd_read_seek_table(zstd)) {
+    zstd->reader.read = zstd_read_seekable;
+    zstd->reader.seek = zstd_seek;
+  }
+  else {
+    zstd->reader.read = zstd_read;
+    zstd->reader.seek = NULL;
+
+    zstd->in_buf_max_size = ZSTD_DStreamInSize();
+    zstd->in_buf.src = MEM_mallocN(zstd->in_buf_max_size, "zstd in buf");
+    zstd->in_buf.size = zstd->in_buf_max_size;
+    /* This signals that the buffer has run out,
+     * which will make the read function refill it on the first call. */
+    zstd->in_buf.pos = zstd->in_buf_max_size;
+  }
+  zstd->reader.close = zstd_close;
+
+  return (FileReader *)zstd;
+}
diff --git a/source/blender/blenloader/BLO_undofile.h b/source/blender/blenloader/BLO_undofile.h
index fc41a6e832f..4e240e2462b 100644
--- a/source/blender/blenloader/BLO_undofile.h
+++ b/source/blender/blenloader/BLO_undofile.h
@@ -24,6 +24,8 @@
  * \ingroup blenloader
  */
 
+#include "BLI_filereader.h"
+
 struct GHash;
 struct Scene;
 
@@ -65,6 +67,16 @@ typedef struct MemFileUndoData {
   size_t undo_size;
 } MemFileUndoData;
 
+/* FileReader-compatible wrapper for reading MemFiles */
+typedef struct {
+  FileReader reader;
+
+  MemFile *memfile;
+  int undo_direction;
+
+  bool memchunk_identical;
+} UndoReader;
+
 /* actually only used writefile.c */
 
 void BLO_memfile_write_init(MemFileWriteData *mem_data,
@@ -84,3 +96,5 @@ extern struct Main *BLO_memfile_main_get(struct MemFile *memfile,
                                          struct Main *bmain,
                                          struct Scene **r_scene);
 extern bool BLO_memfile_write_file(struct MemFile *memfile, const char *filename);
+
+FileReader *BLO_memfile_new_filereader(MemFile *memfile, int undo_direction);
diff --git a/source/blender/blenloader/CMakeLists.txt b/source/blender/blenloader/CMakeLists.txt
index f5baf0dcb83..89631588ed0 100644
--- a/source/blender/blenloader/CMakeLists.txt
+++ b/source/blender/blenloader/CMakeLists.txt
@@ -42,7 +42,7 @@ set(INC
 )
 
 set(INC_SYS
-  ${ZLIB_INCLUDE_DIRS}
+  ${ZSTD_INCLUDE_DIRS}
 )
 
 set(SRC
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index e48c305fc4b..49c3497f996 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -21,8 +21,6 @@
  * \ingroup blenloader
  */
 
-#include "zlib.h"
-
 #include <ctype.h> /* for isdigit. */
 #include <fcntl.h> /* for open flags (O_BINARY, O_RDONLY). */
 #include <limits.h>
@@ -71,7 +69,6 @@
 #include "BLI_math.h"
 #include "BLI_memarena.h"
 #include "BLI_mempool.h"
-#include "BLI_mmap.h"
 #include "BLI_threads.h"
 
 #include "PIL_time.h"
@@ -788,7 +785,7 @@ static BHeadN *get_bhead(FileData *fd)
        */
       if (fd->flags & FD_FLAGS_FILE_POINTSIZE_IS_4) {
         bhead4.code = DATA;
-        readsize = fd->read(fd, &bhead4, sizeof(bhead4), NULL);
+        readsize = fd->file->read(fd->file, &bhead4, sizeof(bhead4));
 
         if (readsize == sizeof(bhead4) || bhead4.code == ENDB) {
           if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
@@ -811,7 +808,7 @@ static BHeadN *get_bhead(FileData *fd)
       }
       else {
         bhead8.code = DATA;
-        readsize = fd->read(fd, &bhead8, sizeof(bhead8), NULL);
+        readsize = fd->file->read(fd->file, &bhead8, sizeof(bhead8));
 
         if (readsize == sizeof(bhead8) || bhead8.code == ENDB) {
           if (fd->flags & FD_FLAGS_SWITCH_ENDIAN) {
@@ -845,22 +842,22 @@ static BHeadN *get_bhead(FileData *fd)
         /* pass */
       }
 #ifdef USE_BHEAD_READ_ON_DEMAND
-      else if (fd->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&bhead)) {
+      else if (fd->file->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&bhead)) {
         /* Delay reading bhead content. */
         new_bhead = MEM_mallocN(sizeof(BHeadN), "new_bhead");
         if (new_bhead) {
           new_bhead->next = new_bhead->prev = NULL;
-          new_bhead->file_offset = fd->file_offset;
+          new_bhead->file_offset = fd->file->offset;
           new_bhead->has_data = false;
           new_bhead->is_memchunk_identical = false;
           new_bhead->bhead = bhead;
-          off64_t seek_new = fd->seek(fd, bhead.len, SEEK_CUR);
+          off64_t seek_new = fd->file->seek(fd->file, bhead.len, SEEK_CUR);
           if (seek_new == -1) {
             fd->is_eof = true;
             MEM_freeN(new_bhead);
             new_bhead = NULL;
           }
-          BLI_assert(fd->file_offset == seek_new);
+          BLI_assert(fd->file->offset == seek_new);
         }
         else {
           fd->is_eof = true;
@@ -878,14 +875,17 @@ static BHeadN *get_bhead(FileData *fd)
           new_bhead->is_memchunk_identical = false;
           new_bhead->bhead = bhead;
 
-          readsize = fd->read(
-              fd, new_bhead + 1, (size_t)bhead.len, &new_bhead->is_memchunk_identical);
+          readsize = fd->file->read(fd->file, new_bhead + 1, (size_t)bhead.len);
 
-          if (readsize != (ssize_t)bhead.len) {
+          if (readsize != bhead.len) {
             fd->is_eof = true;
             MEM_freeN(new_bhead);
             new_bhead = NULL;
           }
+
+          if (fd->flags & FD_FLAGS_IS_MEMFILE) {
+            new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
+          }
         }
         else {
           fd->is_eof = true;
@@ -964,17 +964,19 @@ static bool blo_bhead_read_data(FileData *fd, BHead *thisblock, void *buf)
   bool success = true;
   BHeadN *new_bhead = BHEADN_FROM_BHEAD(thisblock);
   BLI_assert(new_bhead->has_data == false && new_bhead->file_offset != 0);
-  off64_t offset_backup = fd->file_offset;
-  if (UNLIKELY(fd->seek(fd, new_bhead->file_offset, SEEK_SET) == -1)) {
+  off64_t offset_backup = fd->file->offset;
+  if (UNLIKELY(fd->file->seek(fd->file, new_bhead->file_offset, SEEK_SET) == -1)) {
     success = false;
   }
   else {
-    if (fd->read(fd, buf, (size_t)new_bhead->bhead.len, &new_bhead->is_memchunk_identical) !=
-        (ssize_t)new_bhead->bhead.len) {
+    if (fd->file->read(fd->file, buf, (size_t)new_bhead->bhead.len) != new_bhead->bhead.len) {
       success = false;
     }
+    if (fd->flags & FD_FLAGS_IS_MEMFILE) {
+      new_bhead->is_memchunk_identical = ((UndoReader *)fd->file)->memchunk_identical;
+    }
   }
-  if (fd->seek(fd, offset_backup, SEEK_SET) == -1) {
+  if (fd->file->seek(fd->file, offset_backup, SEEK_SET) == -1) {
     success = false;
   }
   return success;
@@ -1017,7 +1019,7 @@ static void decode_blender_header(FileData *fd)
   ssize_t readsize;
 
   /* read in the header data */
-  readsize = fd->read(fd, header, sizeof(header), NULL);
+  readsize = fd->file->read(fd->file, header, sizeof(header));
 
   if (readsize == sizeof(header) && STREQLEN(header, "BLENDER", 7) && ELEM(header[7], '_', '-') &&
       ELEM(header[8], 'v', 'V') &&
@@ -1147,210 +1149,12 @@ static int *read_file_thumbnail(FileData *fd)
 
 /** \} */
 
-/* -------------------------------------------------------------------- */
-/** \name File Data API
- * \{ */
-
-/* Regular file reading. */
-
-static ssize_t fd_read_data_from_file(FileData *filedata,
-                                      void *buffer,
-                                      size_t size,
-                                      bool *UNUSED(r_is_memchunck_identical))
-{
-  ssize_t readsize = read(filedata->filedes, buffer, size);
-
-  if (readsize < 0) {
-    readsize = EOF;
-  }
-  else {
-    filedata->file_offset += readsize;
-  }
-
-  return readsize;
-}
-
-static off64_t fd_seek_data_from_file(FileData *filedata, off64_t offset, int whence)
-{
-  filedata->file_offset = BLI_lseek(filedata->filedes, offset, whence);
-  return filedata->file_offset;
-}
-
-/* GZip file reading. */
-
-static ssize_t fd_read_gzip_from_file(FileData *filedata,
-                                      void *buffer,
-                                      size_t size,
-                                      bool *UNUSED(r_is_memchunck_identical))
-{
-  BLI_assert(size <= INT_MAX);
-
-  ssize_t readsize = gzread(filedata->gzfiledes, buffer, (uint)size);
-
-  if (readsize < 0) {
-    readsize = EOF;
-  }
-  else {
-    filedata->file_offset += readsize;
-  }
-
-  return readsize;
-}
-
-/* Memory reading. */
-
-static ssize_t fd_read_from_memory(FileData *filedata,
-                                   void *buffer,
-                                   size_t size,
-                                   bool *UNUSED(r_is_memchunck_identical))
-{
-  /* don't read more bytes than there are available in the buffer */
-  ssize_t readsize = (ssize_t)MIN2(size, filedata->buffersize - (size_t)filedata->file_offset);
-
-  memcpy(buffer, filedata->buffer + filedata->file_offset, (size_t)readsize);
-  filedata->file_offset += readsize;
-
-  return readsize;
-}
-
-/* Memory-mapped file reading.
- * By using mmap(), we can map a file so that it can be treated like normal memory,
- * meaning that we can just read from it with memcpy() etc.
- * This avoids system call overhead and can significantly speed up file loading.
- */
-
-static ssize_t fd_read_from_mmap(FileData *filedata,
-                                 void *buffer,
-                                 size_t size,
-                                 bool *UNUSED(r_is_memchunck_identical))
-{
-  /* don't read more bytes than there are available in the buffer */
-  size_t readsize = MIN2(size, (size_t)(filedata->buffersize - filedata->file_offset));
-
-  if (!BLI_mmap_read(filedata->mmap_file, buffer, filedata->file_offset, readsize)) {
-    return 0;
-  }
-
-  filedata->file_offset += readsize;
-
-  return readsize;
-}
-
-static off64_t fd_seek_from_mmap(FileData *filedata, off64_t offset, int whence)
-{
-  off64_t new_pos;
-  if (whence == SEEK_CUR) {
-    new_pos = filedata->file_offset + offset;
-  }
-  else if (whence == SEEK_SET) {
-    new_pos = offset;
-  }
-  else if (whence == SEEK_END) {
-    new_pos = filedata->buffersize + offset;
-  }
-  else {
-    return -1;
-  }
-
-  if (new_pos < 0 || new_pos > filedata->buffersize) {
-    return -1;
-  }
-
-  filedata->file_offset = new_pos;
-  return filedata->file_offset;
-}
-
-/* MemFile reading. */
-
-static ssize_t fd_read_from_memfile(FileData *filedata,
-                                    void *buffer,
-                                    size_t size,
-                                    bool *r_is_memchunck_identical)
-{
-  static size_t seek = SIZE_MAX; /* the current position */
-  static size_t offset = 0;      /* size of previous chunks */
-  static MemFileChunk *chunk = NULL;
-  size_t chunkoffset, readsize, totread;
-
-  if (r_is_memchunck_identical != NULL) {
-    *r_is_memchunck_identical = true;
-  }
-
-  if (size == 0) {
-    return 0;
-  }
-
-  if (seek != (size_t)filedata->file_offset) {
-    chunk = filedata->memfile->chunks.first;
-    seek = 0;
-
-    while (chunk) {
-      if (seek + chunk->size > (size_t)filedata->file_offset) {
-        break;
-      }
-      seek += chunk->size;
-      chunk = chunk->next;
-    }
-    offset = seek;
-    seek = (size_t)filedata->file_offset;
-  }
-
-  if (chunk) {
-    totread = 0;
-
-    do {
-      /* first check if it's on the end if current chunk */
-      if (seek - offset == chunk->size) {
-        offset += chunk->size;
-        chunk = chunk->next;
-      }
-
-      /* debug, should never happen */
-      if (chunk == NULL) {
-        CLOG_ERROR(&LOG, "Illegal read, got a NULL chunk");
-        return 0;
-      }
-
-      chunkoffset = seek - offset;
-      readsize = size - totread;
-
-      /* data can be spread over multiple chunks, so clamp size
-       * to within this chunk, and then it will read further in
-       * the next chunk */
-      if (chunkoffset + readsize > chunk->size) {
-        readsize = chunk->size - chunkoffset;
-      }
-
-      memcpy(POINTER_OFFSET(buffer, totread), chunk->buf + chunkoffset, readsize);
-      totread += readsize;
-      filedata->file_offset += readsize;
-      seek += readsize;
-      if (r_is_memchunck_identical != NULL) {
-        /* `is_identical` of current chunk represents whether it changed compared to previous undo
-         * step. this is fine in redo case, but not in undo case, where we need an extra flag
-         * defined when saving the next (future) step after the one we want to restore, as we are
-         * supposed to 'come from' that future undo step, and not the one before current one. */
-        *r_is_memchunck_identical &= filedata->undo_direction == STEP_REDO ?
-                                         chunk->is_identical :
-                                         chunk->is_identical_future;
-      }
-    } while (totread < size);
-
-    return (ssize_t)totread;
-  }
-
-  return 0;
-}
-
 static FileData *filedata_new(BlendFileReadReport *reports)
 {
   BLI_assert(reports != NULL);
 
   FileData *fd = MEM_callocN(sizeof(FileData), "FileData");
 
-  fd->filedes = -1;
-  fd->gzfiledes = NULL;
-
   fd->memsdna = DNA_sdna_current_get();
 
   fd->datamap = oldnewmap_new();
@@ -1387,78 +1191,66 @@ static FileData *blo_decode_and_check(FileData *fd, ReportList *reports)
 
 static FileData *blo_filedata_from_file_descriptor(const char *filepath,
                                                    BlendFileReadReport *reports,
-                                                   int file)
+                                                   int filedes)
 {
-  FileDataReadFn *read_fn = NULL;
-  FileDataSeekFn *seek_fn = NULL; /* Optional. */
-  size_t buffersize = 0;
-  BLI_mmap_file *mmap_file = NULL;
-
-  gzFile gzfile = (gzFile)Z_NULL;
-
   char header[7];
+  FileReader *rawfile = BLI_filereader_new_file(filedes);
+  FileReader *file = NULL;
 
-  /* Regular file. */
   errno = 0;
-  if (read(file, header, sizeof(header)) != sizeof(header)) {
+  /* If opening the file failed or we can't read the header, give up. */
+  if (rawfile == NULL || rawfile->read(rawfile, header, sizeof(header)) != sizeof(header)) {
     BKE_reportf(reports->reports,
                 RPT_WARNING,
                 "Unable to read '%s': %s",
                 filepath,
                 errno ? strerror(errno) : TIP_("insufficient content"));
+    if (rawfile) {
+      rawfile->close(rawfile);
+    }
+    else {
+      close(filedes);
+    }
     return NULL;
   }
 
-  /* Regular file. */
-  if (memcmp(header, "BLENDER", sizeof(header)) == 0) {
-    read_fn = fd_read_data_from_file;
-    seek_fn = fd_seek_data_from_file;
+  /* Rewind the file after reading the header. */
+  rawfile->seek(rawfile, 0, SEEK_SET);
 
-    mmap_file = BLI_mmap_open(file);
-    if (mmap_file != NULL) {
-      read_fn = fd_read_from_mmap;
-      seek_fn = fd_seek_from_mmap;
-      buffersize = BLI_lseek(file, 0, SEEK_END);
+  /* Check if we have a regular file. */
+  if (memcmp(header, "BLENDER", sizeof(header)) == 0) {
+    /* Try opening the file with memory-mapped IO. */
+    file = BLI_filereader_new_mmap(filedes);
+    if (file == NULL) {
+      /* mmap failed, so just keep using rawfile. */
+      file = rawfile;
+      rawfile = NULL;
     }
   }
-
-  BLI_lseek(file, 0, SEEK_SET);
-
-  /* Gzip file. */
-  errno = 0;
-  if ((read_fn == NULL) &&
-      /* Check header magic. */
-      (header[0] == 0x1f && header[1] == 0x8b)) {
-    gzfile = BLI_gzopen(filepath, "rb");
-    if (gzfile == (gzFile)Z_NULL) {
-      BKE_reportf(reports->reports,
-                  RPT_WARNING,
-                  "Unable to open '%s': %s",
-                  filepath,
-                  errno ? strerror(errno) : TIP_("unknown error reading file"));
-      return NULL;
+  else if (BLI_file_magic_is_gzip(header)) {
+    file = BLI_filereader_new_gzip(rawfile);
+    if (file != NULL) {
+      rawfile = NULL; /* The Gzip FileReader takes ownership of `rawfile`. */
+    }
+  }
+  else if (BLI_file_magic_is_zstd(header)) {
+    file = BLI_filereader_new_zstd(rawfile);
+    if (file != NULL) {
+      rawfile = NULL; /* The Zstd FileReader takes ownership of `rawfile`. */
     }
-
-    /* 'seek_fn' is too slow for gzip, don't set it. */
-    read_fn = fd_read_gzip_from_file;
-    /* Caller must close. */
-    file = -1;
   }
 
-  if (read_fn == NULL) {
+  /* Clean up `rawfile` if it wasn't taken over. */
+  if (rawfile != NULL) {
+    rawfile->close(rawfile);
+  }
+  if (file == NULL) {
     BKE_reportf(reports->reports, RPT_WARNING, "Unrecognized file format '%s'", filepath);
     return NULL;
   }
 
   FileData *fd = filedata_new(reports);
-
-  fd->filedes = file;
-  fd->gzfiledes = gzfile;
-
-  fd->read = read_fn;
-  fd->seek = seek_fn;
-  fd->mmap_file = mmap_file;
-  fd->buffersize = buffersize;
+  fd->file = file;
 
   return fd;
 }
@@ -1475,11 +1267,7 @@ static FileData *blo_filedata_from_file_open(const char *filepath, BlendFileRead
                 errno ? strerror(errno) : TIP_("unknown error reading file"));
     return NULL;
   }
-  FileData *fd = blo_filedata_from_file_descriptor(filepath, reports, file);
-  if ((fd == NULL) || (fd->filedes == -1)) {
-    close(file);
-  }
-  return fd;
+  return blo_filedata_from_file_descriptor(filepath, reports, file);
 }
 
 /* cannot be called with relative paths anymore! */
@@ -1513,50 +1301,6 @@ static FileData *blo_filedata_from_file_minimal(const char *filepath)
   return NULL;
 }
 
-static ssize_t fd_read_gzip_from_memory(FileData *filedata,
-                                        void *buffer,
-                                        size_t size,
-                                        bool *UNUSED(r_is_memchunck_identical))
-{
-  int err;
-
-  filedata->strm.next_out = (Bytef *)buffer;
-  filedata->strm.avail_out = (uint)size;
-
-  /* Inflate another chunk. */
-  err = inflate(&filedata->strm, Z_SYNC_FLUSH);
-
-  if (err == Z_STREAM_END) {
-    return 0;
-  }
-  if (err != Z_OK) {
-    CLOG_ERROR(&LOG, "ZLib error (code %d)", err);
-    return 0;
-  }
-
-  filedata->file_offset += size;
-
-  return (ssize_t)size;
-}
-
-static int fd_read_gzip_from_memory_init(FileData *fd)
-{
-
-  fd->strm.next_in = (Bytef *)fd->buffer;
-  fd->strm.avail_in = fd->buffersize;
-  fd->strm.total_out = 0;
-  fd->strm.zalloc = Z_NULL;
-  fd->strm.zfree = Z_NULL;
-
-  if (inflateInit2(&fd->strm, (16 + MAX_WBITS)) != Z_OK) {
-    return 0;
-  }
-
-  fd->read = fd_read_gzip_from_memory;
-
-  return 1;
-}
-
 FileData *blo_filedata_from_memory(const void *mem, int memsize, BlendFileReadReport *reports)
 {
   if (!mem || memsize < SIZEOFBLENDERHEADER) {
@@ -1565,24 +1309,24 @@ FileData *blo_filedata_from_memory(const void *mem, int memsize, BlendFileReadRe
     return NULL;
   }
 
-  FileData *fd = filedata_new(reports);
-  const char *cp = mem;
-
-  fd->buffer = mem;
-  fd->buffersize = memsize;
+  FileReader *mem_file = BLI_filereader_new_memory(mem, memsize);
+  FileReader *file = mem_file;
 
-  /* test if gzip */
-  if (cp[0] == 0x1f && cp[1] == 0x8b) {
-    if (0 == fd_read_gzip_from_memory_init(fd)) {
-      blo_filedata_free(fd);
-      return NULL;
-    }
+  if (BLI_file_magic_is_gzip(mem)) {
+    file = BLI_filereader_new_gzip(mem_file);
   }
-  else {
-    fd->read = fd_read_from_memory;
+  else if (BLI_file_magic_is_zstd(mem)) {
+    file = BLI_filereader_new_zstd(mem_file);
   }
 
-  fd->flags |= FD_FLAGS_NOT_MY_BUFFER;
+  if (file == NULL) {
+    /* Compression initialization failed. */
+    mem_file->close(mem_file);
+    return NULL;
+  }
+
+  FileData *fd = filedata_new(reports);
+  fd->file = file;
 
   return blo_decode_and_check(fd, reports->reports);
 }
@@ -1597,11 +1341,9 @@ FileData *blo_filedata_from_memfile(MemFile *memfile,
   }
 
   FileData *fd = filedata_new(reports);
-  fd->memfile = memfile;
+  fd->file = BLO_memfile_new_filereader(memfile, params->undo_direction);
   fd->undo_direction = params->undo_direction;
-
-  fd->read = fd_read_from_memfile;
-  fd->flags |= FD_FLAGS_NOT_MY_BUFFER;
+  fd->flags |= FD_FLAGS_IS_MEMFILE;
 
   return blo_decode_and_check(fd, reports->reports);
 }
@@ -1609,30 +1351,7 @@ FileData *blo_filedata_from_memfile(MemFile *memfile,
 void blo_filedata_free(FileData *fd)
 {
   if (fd) {
-    if (fd->filedes != -1) {
-      close(fd->filedes);
-    }
-
-    if (fd->gzfiledes != NULL) {
-      gzclose(fd->gzfiledes);
-    }
-
-    if (fd->strm.next_in) {
-      int err = inflateEnd(&fd->strm);
-      if (err != Z_OK) {
-        CLOG_ERROR(&LOG, "Close gzip stream error (code %d)", err);
-      }
-    }
-
-    if (fd->buffer && !(fd->flags & FD_FLAGS_NOT_MY_BUFFER)) {
-      MEM_freeN((void *)fd->buffer);
-      fd->buffer = NULL;
-    }
-
-    if (fd->mmap_file) {
-      BLI_mmap_free(fd->mmap_file);
-      fd->mmap_file = NULL;
-    }
+    fd->file->close(fd->file);
 
     /* Free all BHeadN data blocks */
 #ifndef NDEBUG
@@ -1640,7 +1359,7 @@ void blo_filedata_free(FileData *fd)
 #else
     /* Sanity check we're not keeping memory we don't need. */
     LISTBASE_FOREACH_MUTABLE (BHeadN *, new_bhead, &fd->bhead_list) {
-      if (fd->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&new_bhead->bhead)) {
+      if (fd->file->seek != NULL && BHEAD_USE_READ_ON_DEMAND(&new_bhead->bhead)) {
         BLI_assert(new_bhead->has_data == 0);
       }
       MEM_freeN(new_bhead);
@@ -2096,7 +1815,7 @@ static void blo_cache_storage_entry_clear_in_old(ID *UNUSED(id),
 
 void blo_cache_storage_init(FileData *fd, Main *bmain)
 {
-  if (fd->memfile != NULL) {
+  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
     BLI_assert(fd->cache_storage == NULL);
     fd->cache_storage = MEM_mallocN(sizeof(*fd->cache_storage), __func__);
     fd->cache_storage->memarena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
@@ -2261,7 +1980,7 @@ static void *read_struct(FileData *fd, BHead *bh, const char *blockname)
  * undo since DNA must match. */
 static const void *peek_struct_undo(FileData *fd, BHead *bhead)
 {
-  BLI_assert(fd->memfile != NULL);
+  BLI_assert(fd->flags & FD_FLAGS_IS_MEMFILE);
   UNUSED_VARS_NDEBUG(fd);
   return (bhead->len) ? (const void *)(bhead + 1) : NULL;
 }
@@ -3679,7 +3398,7 @@ static BHead *read_libblock(FileData *fd,
    * When datablocks are changed but still exist, we restore them at the old
    * address and inherit recalc flags for the dependency graph. */
   ID *id_old = NULL;
-  if (fd->memfile != NULL) {
+  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
     if (read_libblock_undo_restore(fd, main, bhead, tag, &id_old)) {
       if (r_id) {
         *r_id = id_old;
@@ -3980,13 +3699,14 @@ static void lib_link_all(FileData *fd, Main *bmain)
       continue;
     }
 
-    if (fd->memfile != NULL && GS(id->name) == ID_WM) {
+    if ((fd->flags & FD_FLAGS_IS_MEMFILE) && GS(id->name) == ID_WM) {
       /* No load UI for undo memfiles.
        * Only WM currently, SCR needs it still (see below), and so does WS? */
       continue;
     }
 
-    if (fd->memfile != NULL && do_partial_undo && (id->tag & LIB_TAG_UNDO_OLD_ID_REUSED) != 0) {
+    if ((fd->flags & FD_FLAGS_IS_MEMFILE) && do_partial_undo &&
+        (id->tag & LIB_TAG_UNDO_OLD_ID_REUSED) != 0) {
       /* This ID has been re-used from 'old' bmain. Since it was therefore unchanged across
        * current undo step, and old IDs re-use their old memory address, we do not need to liblink
        * it at all. */
@@ -4165,7 +3885,7 @@ BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
   BlendFileData *bfd;
   ListBase mainlist = {NULL, NULL};
 
-  if (fd->memfile != NULL) {
+  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
     CLOG_INFO(&LOG_UNDO, 2, "UNDO: read step");
   }
 
@@ -4256,7 +3976,7 @@ BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
   }
 
   /* do before read_libraries, but skip undo case */
-  if (fd->memfile == NULL) {
+  if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
     if ((fd->skip_flags & BLO_READ_SKIP_DATA) == 0) {
       do_versions(fd, NULL, bfd->main);
     }
@@ -4278,7 +3998,7 @@ BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
     fd->reports->duration.libraries = PIL_check_seconds_timer() - fd->reports->duration.libraries;
 
     /* Skip in undo case. */
-    if (fd->memfile == NULL) {
+    if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
       /* Note that we can't recompute user-counts at this point in undo case, we play too much with
        * IDs from different memory realms, and Main database is not in a fully valid state yet.
        */
@@ -4311,7 +4031,7 @@ BlendFileData *blo_read_file_internal(FileData *fd, const char *filepath)
 
     /* Now that all our data-blocks are loaded,
      * we can re-generate overrides from their references. */
-    if (fd->memfile == NULL) {
+    if ((fd->flags & FD_FLAGS_IS_MEMFILE) == 0) {
       /* Do not apply in undo case! */
       fd->reports->duration.lib_overrides = PIL_check_seconds_timer();
 
@@ -4391,7 +4111,7 @@ static void sort_bhead_old_map(FileData *fd)
 static BHead *find_previous_lib(FileData *fd, BHead *bhead)
 {
   /* Skip library data-blocks in undo, see comment in read_libblock. */
-  if (fd->memfile) {
+  if (fd->flags & FD_FLAGS_IS_MEMFILE) {
     return NULL;
   }
 
@@ -5850,7 +5570,7 @@ void BLO_read_pointer_array(BlendDataReader *reader, void **ptr_p)
 
 bool BLO_read_data_is_undo(BlendDataReader *reader)
 {
-  return reader->fd->memfile != NULL;
+  return (reader->fd->flags & FD_FLAGS_IS_MEMFILE);
 }
 
 void BLO_read_data_globmap_add(BlendDataReader *reader, void *oldaddr, void *newaddr)
@@ -5870,7 +5590,7 @@ BlendFileReadReport *BLO_read_data_reports(BlendDataReader *reader)
 
 bool BLO_read_lib_is_undo(BlendLibReader *reader)
 {
-  return reader->fd->memfile != NULL;
+  return (reader->fd->flags & FD_FLAGS_IS_MEMFILE);
 }
 
 Main *BLO_read_lib_get_main(BlendLibReader *reader)
diff --git a/source/blender/blenloader/intern/readfile.h b/source/blender/blenloader/intern/readfile.h
index b04043f9641..beeed8e45ae 100644
--- a/source/blender/blenloader/intern/readfile.h
+++ b/source/blender/blenloader/intern/readfile.h
@@ -28,10 +28,10 @@
 #  include "BLI_winstuff.h"
 #endif
 
+#include "BLI_filereader.h"
 #include "DNA_sdna_types.h"
 #include "DNA_space_types.h"
 #include "DNA_windowmanager_types.h" /* for ReportType */
-#include "zlib.h"
 
 struct BLI_mmap_file;
 struct BLOCacheStorage;
@@ -50,7 +50,7 @@ enum eFileDataFlag {
   FD_FLAGS_FILE_POINTSIZE_IS_4 = 1 << 1,
   FD_FLAGS_POINTSIZE_DIFFERS = 1 << 2,
   FD_FLAGS_FILE_OK = 1 << 3,
-  FD_FLAGS_NOT_MY_BUFFER = 1 << 4,
+  FD_FLAGS_IS_MEMFILE = 1 << 4,
   /* XXX Unused in practice (checked once but never set). */
   FD_FLAGS_NOT_MY_LIBMAP = 1 << 5,
 };
@@ -60,44 +60,18 @@ enum eFileDataFlag {
 #  pragma GCC poison off_t
 #endif
 
-#if defined(_MSC_VER) || defined(__APPLE__) || defined(__HAIKU__) || defined(__NetBSD__)
-typedef int64_t off64_t;
-#endif
-
-typedef ssize_t(FileDataReadFn)(struct FileData *filedata,
-                                void *buffer,
-                                size_t size,
-                                bool *r_is_memchunk_identical);
-typedef off64_t(FileDataSeekFn)(struct FileData *filedata, off64_t offset, int whence);
-
 typedef struct FileData {
   /** Linked list of BHeadN's. */
   ListBase bhead_list;
   enum eFileDataFlag flags;
   bool is_eof;
-  size_t buffersize;
-  off64_t file_offset;
 
-  FileDataReadFn *read;
-  FileDataSeekFn *seek;
+  FileReader *file;
 
-  /** Regular file reading. */
-  int filedes;
-
-  /** Variables needed for reading from memory / stream / memory-mapped files. */
-  const char *buffer;
-  struct BLI_mmap_file *mmap_file;
-  /** Variables needed for reading from memfile (undo). */
-  struct MemFile *memfile;
   /** Whether we are undoing (< 0) or redoing (> 0), used to choose which 'unchanged' flag to use
    * to detect unchanged data from memfile. */
   int undo_direction; /* eUndoStepDir */
 
-  /** Variables needed for reading from file. */
-  gzFile gzfiledes;
-  /** Gzip stream for memory decompression. */
-  z_stream strm;
-
   /** Now only in use for library appending. */
   char relabase[FILE_MAX];
 
diff --git a/source/blender/blenloader/intern/undofile.c b/source/blender/blenloader/intern/undofile.c
index 2eeeac2e8d7..62072cf7df5 100644
--- a/source/blender/blenloader/intern/undofile.c
+++ b/source/blender/blenloader/intern/undofile.c
@@ -48,6 +48,7 @@
 
 #include "BKE_lib_id.h"
 #include "BKE_main.h"
+#include "BKE_undo_system.h"
 
 /* keep last */
 #include "BLI_strict_flags.h"
@@ -273,3 +274,97 @@ bool BLO_memfile_write_file(struct MemFile *memfile, const char *filename)
   }
   return true;
 }
+
+static ssize_t undo_read(FileReader *reader, void *buffer, size_t size)
+{
+  UndoReader *undo = (UndoReader *)reader;
+
+  static size_t seek = SIZE_MAX; /* The current position. */
+  static size_t offset = 0;      /* Size of previous chunks. */
+  static MemFileChunk *chunk = NULL;
+  size_t chunkoffset, readsize, totread;
+
+  undo->memchunk_identical = true;
+
+  if (size == 0) {
+    return 0;
+  }
+
+  if (seek != (size_t)undo->reader.offset) {
+    chunk = undo->memfile->chunks.first;
+    seek = 0;
+
+    while (chunk) {
+      if (seek + chunk->size > (size_t)undo->reader.offset) {
+        break;
+      }
+      seek += chunk->size;
+      chunk = chunk->next;
+    }
+    offset = seek;
+    seek = (size_t)undo->reader.offset;
+  }
+
+  if (chunk) {
+    totread = 0;
+
+    do {
+      /* First check if it's on the end if current chunk. */
+      if (seek - offset == chunk->size) {
+        offset += chunk->size;
+        chunk = chunk->next;
+      }
+
+      /* Debug, should never happen. */
+      if (chunk == NULL) {
+        printf("illegal read, chunk zero\n");
+        return 0;
+      }
+
+      chunkoffset = seek - offset;
+      readsize = size - totread;
+
+      /* Data can be spread over multiple chunks, so clamp size
+       * to within this chunk, and then it will read further in
+       * the next chunk. */
+      if (chunkoffset + readsize > chunk->size) {
+        readsize = chunk->size - chunkoffset;
+      }
+
+      memcpy(POINTER_OFFSET(buffer, totread), chunk->buf + chunkoffset, readsize);
+      totread += readsize;
+      undo->reader.offset += (off64_t)readsize;
+      seek += readsize;
+
+      /* `is_identical` of current chunk represents whether it changed compared to previous undo
+       * step. this is fine in redo case, but not in undo case, where we need an extra flag
+       * defined when saving the next (future) step after the one we want to restore, as we are
+       * supposed to 'come from' that future undo step, and not the one before current one. */
+      undo->memchunk_identical &= undo->undo_direction == STEP_REDO ? chunk->is_identical :
+                                                                      chunk->is_identical_future;
+    } while (totread < size);
+
+    return (ssize_t)totread;
+  }
+
+  return 0;
+}
+
+static void undo_close(FileReader *reader)
+{
+  MEM_freeN(reader);
+}
+
+FileReader *BLO_memfile_new_filereader(MemFile *memfile, int undo_direction)
+{
+  UndoReader *undo = MEM_callocN(sizeof(UndoReader), __func__);
+
+  undo->memfile = memfile;
+  undo->undo_direction = undo_direction;
+
+  undo->reader.read = undo_read;
+  undo->reader.seek = NULL;
+  undo->reader.close = undo_close;
+
+  return (FileReader *)undo;
+}
diff --git a/source/blender/blenloader/intern/versioning_250.c b/source/blender/blenloader/intern/versioning_250.c
index e56c1995363..436645c2241 100644
--- a/source/blender/blenloader/intern/versioning_250.c
+++ b/source/blender/blenloader/intern/versioning_250.c
@@ -23,8 +23,7 @@
 #else
 #  include "BLI_winstuff.h"
 #  include "winsock2.h"
-#  include <io.h>   /* for open close read */
-#  include <zlib.h> /* odd include order-issue */
+#  include <io.h> /* for open close read */
 #endif
 
 /* allow readfile to use deprecated functionality */
diff --git a/source/blender/blenloader/intern/versioning_legacy.c b/source/blender/blenloader/intern/versioning_legacy.c
index 81371e1c1ed..6ba27b6ee9e 100644
--- a/source/blender/blenloader/intern/versioning_legacy.c
+++ b/source/blender/blenloader/intern/versioning_legacy.c
@@ -28,8 +28,7 @@
 #else
 #  include "BLI_winstuff.h"
 #  include "winsock2.h"
-#  include <io.h>   /* for open close read */
-#  include <zlib.h> /* odd include order-issue */
+#  include <io.h> /* for open close read */
 #endif
 
 /* allow readfile to use deprecated functionality */
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index 99246603e9a..90d58514eb5 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -83,7 +83,6 @@
 #  include "BLI_winstuff.h"
 #  include "winsock2.h"
 #  include <io.h>
-#  include <zlib.h> /* odd include order-issue */
 #else
 #  include <unistd.h> /* FreeBSD, for write() and close(). */
 #endif
@@ -101,7 +100,12 @@
 #include "BLI_bitmap.h"
 #include "BLI_blenlib.h"
 #include "BLI_endian_defines.h"
+#include "BLI_endian_switch.h"
+#include "BLI_link_utils.h"
+#include "BLI_linklist.h"
+#include "BLI_math_base.h"
 #include "BLI_mempool.h"
+#include "BLI_threads.h"
 #include "MEM_guardedalloc.h" /* MEM_freeN */
 
 #include "BKE_blender_version.h"
@@ -129,14 +133,21 @@
 
 #include <errno.h>
 
+#include <zstd.h>
+
 /* Make preferences read-only. */
 #define U (*((const UserDef *)&U))
 
 /* ********* my write, buffered writing with minimum size chunks ************ */
 
 /* Use optimal allocation since blocks of this size are kept in memory for undo. */
-#define MYWRITE_BUFFER_SIZE (MEM_SIZE_OPTIMAL(1 << 17)) /* 128kb */
-#define MYWRITE_MAX_CHUNK (MEM_SIZE_OPTIMAL(1 << 15))   /* ~32kb */
+#define MEM_BUFFER_SIZE (MEM_SIZE_OPTIMAL(1 << 17)) /* 128kb */
+#define MEM_CHUNK_SIZE (MEM_SIZE_OPTIMAL(1 << 15))  /* ~32kb */
+
+#define ZSTD_BUFFER_SIZE (1 << 21) /* 2mb */
+#define ZSTD_CHUNK_SIZE (1 << 20)  /* 1mb */
+
+#define ZSTD_COMPRESSION_LEVEL 3
 
 /** Use if we want to store how many bytes have been written to the file. */
 // #define USE_WRITE_DATA_LEN
@@ -147,9 +158,16 @@
 
 typedef enum {
   WW_WRAP_NONE = 1,
-  WW_WRAP_ZLIB,
+  WW_WRAP_ZSTD,
 } eWriteWrapType;
 
+typedef struct ZstdFrame {
+  struct ZstdFrame *next, *prev;
+
+  uint32_t compressed_size;
+  uint32_t uncompressed_size;
+} ZstdFrame;
+
 typedef struct WriteWrap WriteWrap;
 struct WriteWrap {
   /* callbacks */
@@ -161,15 +179,23 @@ struct WriteWrap {
   bool use_buf;
 
   /* internal */
-  union {
-    int file_handle;
-    gzFile gz_handle;
-  } _user_data;
+  int file_handle;
+  struct {
+    ListBase threadpool;
+    ListBase tasks;
+    ThreadMutex mutex;
+    ThreadCondition condition;
+    int next_frame;
+    int num_frames;
+
+    int level;
+    ListBase frames;
+
+    bool write_error;
+  } zstd;
 };
 
 /* none */
-#define FILE_HANDLE(ww) (ww)->_user_data.file_handle
-
 static bool ww_open_none(WriteWrap *ww, const char *filepath)
 {
   int file;
@@ -177,7 +203,7 @@ static bool ww_open_none(WriteWrap *ww, const char *filepath)
   file = BLI_open(filepath, O_BINARY + O_WRONLY + O_CREAT + O_TRUNC, 0666);
 
   if (file != -1) {
-    FILE_HANDLE(ww) = file;
+    ww->file_handle = file;
     return true;
   }
 
@@ -185,39 +211,170 @@ static bool ww_open_none(WriteWrap *ww, const char *filepath)
 }
 static bool ww_close_none(WriteWrap *ww)
 {
-  return (close(FILE_HANDLE(ww)) != -1);
+  return (close(ww->file_handle) != -1);
 }
 static size_t ww_write_none(WriteWrap *ww, const char *buf, size_t buf_len)
 {
-  return write(FILE_HANDLE(ww), buf, buf_len);
+  return write(ww->file_handle, buf, buf_len);
 }
-#undef FILE_HANDLE
 
-/* zlib */
-#define FILE_HANDLE(ww) (ww)->_user_data.gz_handle
+/* zstd */
+
+typedef struct {
+  struct ZstdWriteBlockTask *next, *prev;
+  void *data;
+  size_t size;
+  int frame_number;
+  WriteWrap *ww;
+} ZstdWriteBlockTask;
 
-static bool ww_open_zlib(WriteWrap *ww, const char *filepath)
+static void *zstd_write_task(void *userdata)
 {
-  gzFile file;
+  ZstdWriteBlockTask *task = userdata;
+  WriteWrap *ww = task->ww;
 
-  file = BLI_gzopen(filepath, "wb1");
+  size_t out_buf_len = ZSTD_compressBound(task->size);
+  void *out_buf = MEM_mallocN(out_buf_len, "Zstd out buffer");
+  size_t out_size = ZSTD_compress(
+      out_buf, out_buf_len, task->data, task->size, ZSTD_COMPRESSION_LEVEL);
 
-  if (file != Z_NULL) {
-    FILE_HANDLE(ww) = file;
-    return true;
+  MEM_freeN(task->data);
+
+  BLI_mutex_lock(&ww->zstd.mutex);
+
+  while (ww->zstd.next_frame != task->frame_number) {
+    BLI_condition_wait(&ww->zstd.condition, &ww->zstd.mutex);
   }
 
-  return false;
+  if (ZSTD_isError(out_size)) {
+    ww->zstd.write_error = true;
+  }
+  else {
+    if (ww_write_none(ww, out_buf, out_size) == out_size) {
+      ZstdFrame *frameinfo = MEM_mallocN(sizeof(ZstdFrame), "zstd frameinfo");
+      frameinfo->uncompressed_size = task->size;
+      frameinfo->compressed_size = out_size;
+      BLI_addtail(&ww->zstd.frames, frameinfo);
+    }
+    else {
+      ww->zstd.write_error = true;
+    }
+  }
+
+  ww->zstd.next_frame++;
+
+  BLI_mutex_unlock(&ww->zstd.mutex);
+  BLI_condition_notify_all(&ww->zstd.condition);
+
+  MEM_freeN(out_buf);
+  return NULL;
+}
+
+static bool ww_open_zstd(WriteWrap *ww, const char *filepath)
+{
+  if (!ww_open_none(ww, filepath)) {
+    return false;
+  }
+
+  /* Leave one thread open for the main writing logic, unless we only have one HW thread. */
+  int num_threads = max_ii(1, BLI_system_thread_count() - 1);
+  BLI_threadpool_init(&ww->zstd.threadpool, zstd_write_task, num_threads);
+  BLI_mutex_init(&ww->zstd.mutex);
+  BLI_condition_init(&ww->zstd.condition);
+
+  return true;
 }
-static bool ww_close_zlib(WriteWrap *ww)
+
+static void zstd_write_u32_le(WriteWrap *ww, uint32_t val)
+{
+#ifdef __BIG_ENDIAN__
+  BLI_endian_switch_uint32(&val);
+#endif
+  ww_write_none(ww, (char *)&val, sizeof(uint32_t));
+}
+
+/* In order to implement efficient seeking when reading the .blend, we append
+ * a skippable frame that encodes information about the other frames present
+ * in the file.
+ * The format here follows the upstream spec for seekable files:
+ * https://github.com/facebook/zstd/blob/master/contrib/seekable_format/zstd_seekable_compression_format.md
+ * If this information is not present in a file (e.g. if it was compressed
+ * with external tools), it can still be opened in Blender, but seeking will
+ * not be supported, so more memory might be needed. */
+static void zstd_write_seekable_frames(WriteWrap *ww)
+{
+  /* Write seek table header (magic number and frame size). */
+  zstd_write_u32_le(ww, 0x184D2A5E);
+
+  /* The actual frame number might not match ww->zstd.num_frames if there was a write error. */
+  const uint32_t num_frames = BLI_listbase_count(&ww->zstd.frames);
+  /* Each frame consists of two u32, so 8 bytes each.
+   * After the frames, a footer containing two u32 and one byte (9 bytes total) is written. */
+  const uint32_t frame_size = num_frames * 8 + 9;
+  zstd_write_u32_le(ww, frame_size);
+
+  /* Write seek table entries. */
+  LISTBASE_FOREACH (ZstdFrame *, frame, &ww->zstd.frames) {
+    zstd_write_u32_le(ww, frame->compressed_size);
+    zstd_write_u32_le(ww, frame->uncompressed_size);
+  }
+
+  /* Write seek table footer (number of frames, option flags and second magic number). */
+  zstd_write_u32_le(ww, num_frames);
+  const char flags = 0; /* We don't store checksums for each frame. */
+  ww_write_none(ww, &flags, 1);
+  zstd_write_u32_le(ww, 0x8F92EAB1);
+}
+
+static bool ww_close_zstd(WriteWrap *ww)
 {
-  return (gzclose(FILE_HANDLE(ww)) == Z_OK);
+  BLI_threadpool_end(&ww->zstd.threadpool);
+  BLI_freelistN(&ww->zstd.tasks);
+
+  BLI_mutex_end(&ww->zstd.mutex);
+  BLI_condition_end(&ww->zstd.condition);
+
+  zstd_write_seekable_frames(ww);
+  BLI_freelistN(&ww->zstd.frames);
+
+  return ww_close_none(ww) && !ww->zstd.write_error;
 }
-static size_t ww_write_zlib(WriteWrap *ww, const char *buf, size_t buf_len)
+
+static size_t ww_write_zstd(WriteWrap *ww, const char *buf, size_t buf_len)
 {
-  return gzwrite(FILE_HANDLE(ww), buf, buf_len);
+  if (ww->zstd.write_error) {
+    return 0;
+  }
+
+  ZstdWriteBlockTask *task = MEM_mallocN(sizeof(ZstdWriteBlockTask), __func__);
+  task->data = MEM_mallocN(buf_len, __func__);
+  memcpy(task->data, buf, buf_len);
+  task->size = buf_len;
+  task->frame_number = ww->zstd.num_frames++;
+  task->ww = ww;
+
+  BLI_mutex_lock(&ww->zstd.mutex);
+  BLI_addtail(&ww->zstd.tasks, task);
+
+  /* If there's a free worker thread, just push the block into that thread.
+   * Otherwise, we wait for the earliest thread to finish.
+   * We look up the earliest thread while holding the mutex, but release it
+   * before joining the thread to prevent a deadlock. */
+  ZstdWriteBlockTask *first_task = ww->zstd.tasks.first;
+  BLI_mutex_unlock(&ww->zstd.mutex);
+  if (!BLI_available_threads(&ww->zstd.threadpool)) {
+    BLI_threadpool_remove(&ww->zstd.threadpool, first_task);
+
+    /* If the task list was empty before we pushed our task, there should
+     * always be a free thread. */
+    BLI_assert(first_task != task);
+    BLI_remlink(&ww->zstd.tasks, first_task);
+    MEM_freeN(first_task);
+  }
+  BLI_threadpool_insert(&ww->zstd.threadpool, task);
+
+  return buf_len;
 }
-#undef FILE_HANDLE
 
 /* --- end compression types --- */
 
@@ -226,11 +383,11 @@ static void ww_handle_init(eWriteWrapType ww_type, WriteWrap *r_ww)
   memset(r_ww, 0, sizeof(*r_ww));
 
   switch (ww_type) {
-    case WW_WRAP_ZLIB: {
-      r_ww->open = ww_open_zlib;
-      r_ww->close = ww_close_zlib;
-      r_ww->write = ww_write_zlib;
-      r_ww->use_buf = false;
+    case WW_WRAP_ZSTD: {
+      r_ww->open = ww_open_zstd;
+      r_ww->close = ww_close_zstd;
+      r_ww->write = ww_write_zstd;
+      r_ww->use_buf = true;
       break;
     }
     default: {
@@ -252,10 +409,17 @@ static void ww_handle_init(eWriteWrapType ww_type, WriteWrap *r_ww)
 typedef struct {
   const struct SDNA *sdna;
 
-  /** Use for file and memory writing (fixed size of #MYWRITE_BUFFER_SIZE). */
-  uchar *buf;
-  /** Number of bytes used in #WriteData.buf (flushed when exceeded). */
-  size_t buf_used_len;
+  struct {
+    /** Use for file and memory writing (size stored in max_size). */
+    uchar *buf;
+    /** Number of bytes used in #WriteData.buf (flushed when exceeded). */
+    size_t used_len;
+
+    /** Maximum size of the buffer. */
+    size_t max_size;
+    /** Threshold above which writes get their own chunk. */
+    size_t chunk_size;
+  } buffer;
 
 #ifdef USE_WRITE_DATA_LEN
   /** Total number of bytes written. */
@@ -271,7 +435,7 @@ typedef struct {
   bool use_memfile;
 
   /**
-   * Wrap writing, so we can use zlib or
+   * Wrap writing, so we can use zstd or
    * other compression types later, see: G_FILE_COMPRESS
    * Will be NULL for UNDO.
    */
@@ -291,7 +455,15 @@ static WriteData *writedata_new(WriteWrap *ww)
   wd->ww = ww;
 
   if ((ww == NULL) || (ww->use_buf)) {
-    wd->buf = MEM_mallocN(MYWRITE_BUFFER_SIZE, "wd->buf");
+    if (ww == NULL) {
+      wd->buffer.max_size = MEM_BUFFER_SIZE;
+      wd->buffer.chunk_size = MEM_CHUNK_SIZE;
+    }
+    else {
+      wd->buffer.max_size = ZSTD_BUFFER_SIZE;
+      wd->buffer.chunk_size = ZSTD_CHUNK_SIZE;
+    }
+    wd->buffer.buf = MEM_mallocN(wd->buffer.max_size, "wd->buffer.buf");
   }
 
   return wd;
@@ -325,8 +497,8 @@ static void writedata_do_write(WriteData *wd, const void *mem, size_t memlen)
 
 static void writedata_free(WriteData *wd)
 {
-  if (wd->buf) {
-    MEM_freeN(wd->buf);
+  if (wd->buffer.buf) {
+    MEM_freeN(wd->buffer.buf);
   }
   MEM_freeN(wd);
 }
@@ -343,9 +515,9 @@ static void writedata_free(WriteData *wd)
  */
 static void mywrite_flush(WriteData *wd)
 {
-  if (wd->buf_used_len != 0) {
-    writedata_do_write(wd, wd->buf, wd->buf_used_len);
-    wd->buf_used_len = 0;
+  if (wd->buffer.used_len != 0) {
+    writedata_do_write(wd, wd->buffer.buf, wd->buffer.used_len);
+    wd->buffer.used_len = 0;
   }
 }
 
@@ -369,20 +541,20 @@ static void mywrite(WriteData *wd, const void *adr, size_t len)
   wd->write_len += len;
 #endif
 
-  if (wd->buf == NULL) {
+  if (wd->buffer.buf == NULL) {
     writedata_do_write(wd, adr, len);
   }
   else {
     /* if we have a single big chunk, write existing data in
      * buffer and write out big chunk in smaller pieces */
-    if (len > MYWRITE_MAX_CHUNK) {
-      if (wd->buf_used_len != 0) {
-        writedata_do_write(wd, wd->buf, wd->buf_used_len);
-        wd->buf_used_len = 0;
+    if (len > wd->buffer.chunk_size) {
+      if (wd->buffer.used_len != 0) {
+        writedata_do_write(wd, wd->buffer.buf, wd->buffer.used_len);
+        wd->buffer.used_len = 0;
       }
 
       do {
-        size_t writelen = MIN2(len, MYWRITE_MAX_CHUNK);
+        size_t writelen = MIN2(len, wd->buffer.chunk_size);
         writedata_do_write(wd, adr, writelen);
         adr = (const char *)adr + writelen;
         len -= writelen;
@@ -392,14 +564,14 @@ static void mywrite(WriteData *wd, const void *adr, size_t len)
     }
 
     /* if data would overflow buffer, write out the buffer */
-    if (len + wd->buf_used_len > MYWRITE_BUFFER_SIZE - 1) {
-      writedata_do_write(wd, wd->buf, wd->buf_used_len);
-      wd->buf_used_len = 0;
+    if (len + wd->buffer.used_len > wd->buffer.max_size - 1) {
+      writedata_do_write(wd, wd->buffer.buf, wd->buffer.used_len);
+      wd->buffer.used_len = 0;
     }
 
     /* append data at end of buffer */
-    memcpy(&wd->buf[wd->buf_used_len], adr, len);
-    wd->buf_used_len += len;
+    memcpy(&wd->buffer.buf[wd->buffer.used_len], adr, len);
+    wd->buffer.used_len += len;
   }
 }
 
@@ -430,9 +602,9 @@ static WriteData *mywrite_begin(WriteWrap *ww, MemFile *compare, MemFile *curren
  */
 static bool mywrite_end(WriteData *wd)
 {
-  if (wd->buf_used_len != 0) {
-    writedata_do_write(wd, wd->buf, wd->buf_used_len);
-    wd->buf_used_len = 0;
+  if (wd->buffer.used_len != 0) {
+    writedata_do_write(wd, wd->buffer.buf, wd->buffer.used_len);
+    wd->buffer.used_len = 0;
   }
 
   if (wd->use_memfile) {
@@ -1150,7 +1322,6 @@ bool BLO_write_file(Main *mainvar,
                     ReportList *reports)
 {
   char tempname[FILE_MAX + 1];
-  eWriteWrapType ww_type;
   WriteWrap ww;
 
   eBLO_WritePathRemap remap_mode = params->remap_mode;
@@ -1172,14 +1343,7 @@ bool BLO_write_file(Main *mainvar,
   /* open temporary file, so we preserve the original in case we crash */
   BLI_snprintf(tempname, sizeof(tempname), "%s@", filepath);
 
-  if (write_flags & G_FILE_COMPRESS) {
-    ww_type = WW_WRAP_ZLIB;
-  }
-  else {
-    ww_type = WW_WRAP_NONE;
-  }
-
-  ww_handle_init(ww_type, &ww);
+  ww_handle_init((write_flags & G_FILE_COMPRESS) ? WW_WRAP_ZSTD : WW_WRAP_NONE, &ww);
 
   if (ww.open(&ww, tempname) == false) {
     BKE_reportf(
diff --git a/source/blender/draw/engines/eevee/eevee_lookdev.c b/source/blender/draw/engines/eevee/eevee_lookdev.c
index f4dc553e982..879a7b08eba 100644
--- a/source/blender/draw/engines/eevee/eevee_lookdev.c
+++ b/source/blender/draw/engines/eevee/eevee_lookdev.c
@@ -246,7 +246,7 @@ void EEVEE_lookdev_cache_init(EEVEE_Data *vedata,
       DRW_shgroup_uniform_float_copy(grp, "studioLightIntensity", shading->studiolight_intensity);
       BKE_studiolight_ensure_flag(sl, STUDIOLIGHT_EQUIRECT_RADIANCE_GPUTEXTURE);
       DRW_shgroup_uniform_texture_ex(grp, "studioLight", sl->equirect_radiance_gputexture, state);
-      /* Do not fadeout when doing probe rendering, only when drawing the background */
+      /* Do not fade-out when doing probe rendering, only when drawing the background. */
       DRW_shgroup_uniform_float_copy(grp, "backgroundAlpha", 1.0f);
     }
     else {
diff --git a/source/blender/editors/gpencil/gpencil_interpolate.c b/source/blender/editors/gpencil/gpencil_interpolate.c
index 8640ffa67cf..a8bd3b11bb1 100644
--- a/source/blender/editors/gpencil/gpencil_interpolate.c
+++ b/source/blender/editors/gpencil/gpencil_interpolate.c
@@ -890,9 +890,9 @@ static int gpencil_interpolate_modal(bContext *C, wmOperator *op, const wmEvent
     }
     case MOUSEMOVE: /* calculate new position */
     {
-      /* only handle mousemove if not doing numinput */
+      /* Only handle mouse-move if not doing numeric-input. */
       if (has_numinput == false) {
-        /* update shift based on position of mouse */
+        /* Update shift based on position of mouse. */
         gpencil_mouse_update_shift(tgpi, op, event);
 
         /* update screen */
diff --git a/source/blender/editors/gpencil/gpencil_primitive.c b/source/blender/editors/gpencil/gpencil_primitive.c
index 894fb83d70e..5ecb6d9a212 100644
--- a/source/blender/editors/gpencil/gpencil_primitive.c
+++ b/source/blender/editors/gpencil/gpencil_primitive.c
@@ -1944,9 +1944,9 @@ static int gpencil_primitive_modal(bContext *C, wmOperator *op, const wmEvent *e
       if (ELEM(tgpi->flag, IN_CURVE_EDIT)) {
         break;
       }
-      /* only handle mousemove if not doing numinput */
+      /* Only handle mouse-move if not doing numeric-input. */
       if (has_numinput == false) {
-        /* update position of mouse */
+        /* Update position of mouse. */
         copy_v2_v2(tgpi->end, tgpi->mval);
         copy_v2_v2(tgpi->start, tgpi->origin);
         if (tgpi->flag == IDLE) {
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index b8f324cba83..76f6640c714 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -6025,7 +6025,7 @@ static int ui_do_but_BLOCK(bContext *C, uiBut *but, uiHandleButtonData *data, co
          * the slot menu fails to switch a second time.
          *
          * The active state of the button could be maintained some other way
-         * and remove this mousemove event.
+         * and remove this mouse-move event.
          */
         WM_event_add_mousemove(data->window);
 
@@ -8364,7 +8364,7 @@ static void button_activate_state(bContext *C, uiBut *but, uiHandleButtonState s
     }
   }
 
-  /* wait for mousemove to enable drag */
+  /* Wait for mouse-move to enable drag. */
   if (state == BUTTON_STATE_WAIT_DRAG) {
     but->flag &= ~UI_SELECT;
   }
@@ -8631,9 +8631,9 @@ static void button_activate_exit(
     ui_but_update(but);
   }
 
-  /* adds empty mousemove in queue for re-init handler, in case mouse is
+  /* Adds empty mouse-move in queue for re-initialize handler, in case mouse is
    * still over a button. We cannot just check for this ourselves because
-   * at this point the mouse may be over a button in another region */
+   * at this point the mouse may be over a button in another region. */
   if (mousemove) {
     WM_event_add_mousemove(CTX_wm_window(C));
   }
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index 351b73c320b..0e5a6a79137 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -6489,6 +6489,17 @@ void uiTemplateCacheFile(uiLayout *layout,
   uiLayoutSetActive(row, engine_supports_procedural);
   uiItemR(row, &fileptr, "use_render_procedural", 0, NULL, ICON_NONE);
 
+  const bool use_render_procedural = RNA_boolean_get(&fileptr, "use_render_procedural");
+  const bool use_prefetch = RNA_boolean_get(&fileptr, "use_prefetch");
+
+  row = uiLayoutRow(layout, false);
+  uiLayoutSetEnabled(row, use_render_procedural);
+  uiItemR(row, &fileptr, "use_prefetch", 0, NULL, ICON_NONE);
+
+  sub = uiLayoutRow(layout, false);
+  uiLayoutSetEnabled(sub, use_prefetch && use_render_procedural);
+  uiItemR(sub, &fileptr, "prefetch_cache_size", 0, NULL, ICON_NONE);
+
   row = uiLayoutRowWithHeading(layout, true, IFACE_("Override Frame"));
   sub = uiLayoutRow(row, true);
   uiLayoutSetPropDecorate(sub, false);
diff --git a/source/blender/editors/mesh/editmesh_tools.c b/source/blender/editors/mesh/editmesh_tools.c
index b8bbf2d3e70..956658bd2b7 100644
--- a/source/blender/editors/mesh/editmesh_tools.c
+++ b/source/blender/editors/mesh/editmesh_tools.c
@@ -8627,7 +8627,7 @@ static int edbm_point_normals_modal(bContext *C, wmOperator *op, const wmEvent *
     RNA_enum_set(op->ptr, "mode", mode);
   }
 
-  /* Only handle mousemove event in case we are in mouse mode. */
+  /* Only handle mouse-move event in case we are in mouse mode. */
   if (event->type == MOUSEMOVE || force_mousemove) {
     if (mode == EDBM_CLNOR_POINTTO_MODE_MOUSE) {
       ARegion *region = CTX_wm_region(C);
diff --git a/source/blender/editors/physics/particle_edit.c b/source/blender/editors/physics/particle_edit.c
index 85883a2d29a..8afc5c583e0 100644
--- a/source/blender/editors/physics/particle_edit.c
+++ b/source/blender/editors/physics/particle_edit.c
@@ -4667,7 +4667,7 @@ typedef struct BrushEdit {
   int lastmouse[2];
   float zfac;
 
-  /* optional cached view settings to avoid setting on every mousemove */
+  /** Optional cached view settings to avoid setting on every mouse-move. */
   PEData data;
 } BrushEdit;
 
diff --git a/source/blender/editors/render/render_update.c b/source/blender/editors/render/render_update.c
index 6db148eb4e1..8bc2281db73 100644
--- a/source/blender/editors/render/render_update.c
+++ b/source/blender/editors/render/render_update.c
@@ -64,7 +64,9 @@
 
 #include <stdio.h>
 
-/***************************** Render Engines ********************************/
+/* -------------------------------------------------------------------- */
+/** \name Render Engines
+ * \{ */
 
 /* Update 3D viewport render or draw engine on changes to the scene or view settings. */
 void ED_render_view3d_update(Depsgraph *depsgraph,
@@ -206,15 +208,15 @@ void ED_render_engine_changed(Main *bmain, const bool update_scene_data)
     }
   }
 
-  /* Update CacheFiles to ensure that procedurals are properly taken into account. */
+  /* Update #CacheFiles to ensure that procedurals are properly taken into account. */
   LISTBASE_FOREACH (CacheFile *, cachefile, &bmain->cachefiles) {
-    /* Only update cachefiles which are set to use a render procedural. We do not use
-     * BKE_cachefile_uses_render_procedural here as we need to update regardless of the current
-     * engine or its settings. */
+    /* Only update cache-files which are set to use a render procedural.
+     * We do not use #BKE_cachefile_uses_render_procedural here as we need to update regardless of
+     * the current engine or its settings. */
     if (cachefile->use_render_procedural) {
       DEG_id_tag_update(&cachefile->id, ID_RECALC_COPY_ON_WRITE);
-      /* Rebuild relations so that modifiers are reconnected to or disconnected from the cachefile.
-       */
+      /* Rebuild relations so that modifiers are reconnected to or disconnected from the
+       * cache-file. */
       DEG_relations_tag_update(bmain);
     }
   }
@@ -227,10 +229,16 @@ void ED_render_view_layer_changed(Main *bmain, bScreen *screen)
   }
 }
 
-/***************************** Updates ***********************************
- * ED_render_id_flush_update gets called from DEG_id_tag_update, to do   *
- * editor level updates when the ID changes. when these ID blocks are in *
- * the dependency graph, we can get rid of the manual dependency checks. */
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Updates
+ *
+ * #ED_render_id_flush_update gets called from #DEG_id_tag_update,
+ * to do editor level updates when the ID changes.
+ * When these ID blocks are in the dependency graph,
+ * we can get rid of the manual dependency checks.
+ * \{ */
 
 static void material_changed(Main *UNUSED(bmain), Material *ma)
 {
@@ -336,3 +344,5 @@ void ED_render_id_flush_update(const DEGEditorUpdateContext *update_ctx, ID *id)
       break;
   }
 }
+
+/** \} */
diff --git a/source/blender/editors/space_view3d/view3d_gizmo_ruler.c b/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
index 49299d73337..edc34d0d883 100644
--- a/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
+++ b/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
@@ -299,7 +299,9 @@ static void view3d_ruler_item_project(RulerInfo *ruler_info, float r_co[3], cons
   ED_view3d_win_to_3d_int(ruler_info->area->spacedata.first, ruler_info->region, r_co, xy, r_co);
 }
 
-/* use for mousemove events */
+/**
+ * Use for mouse-move events.
+ */
 static bool view3d_ruler_item_mousemove(struct Depsgraph *depsgraph,
                                         RulerInfo *ruler_info,
                                         RulerItem *ruler_item,
diff --git a/source/blender/editors/transform/transform_convert_action.c b/source/blender/editors/transform/transform_convert_action.c
index 8a3b254be5c..a5565b5fb88 100644
--- a/source/blender/editors/transform/transform_convert_action.c
+++ b/source/blender/editors/transform/transform_convert_action.c
@@ -241,16 +241,15 @@ static int GPLayerToTransData(TransData *td,
   for (gpf = gpl->frames.first; gpf; gpf = gpf->next) {
     if (is_prop_edit || (gpf->flag & GP_FRAME_SELECT)) {
       if (FrameOnMouseSide(side, (float)gpf->framenum, cfra)) {
-        /* memory is calloc'ed, so that should zero everything nicely for us */
-        td->val = &tfd->val;
-        td->ival = (float)gpf->framenum;
+        tfd->val = (float)gpf->framenum;
+        tfd->sdata = &gpf->framenum;
+
+        td->val = td->loc = &tfd->val; /* XXX: It's not a 3d array. */
+        td->ival = td->iloc[0] = (float)gpf->framenum;
 
         td->center[0] = td->ival;
         td->center[1] = ypos;
 
-        tfd->val = (float)gpf->framenum;
-        tfd->sdata = &gpf->framenum;
-
         /* Advance `td` now. */
         td++;
         tfd++;
diff --git a/source/blender/editors/transform/transform_convert_armature.c b/source/blender/editors/transform/transform_convert_armature.c
index f56d60b7376..5627a910ab4 100644
--- a/source/blender/editors/transform/transform_convert_armature.c
+++ b/source/blender/editors/transform/transform_convert_armature.c
@@ -131,12 +131,12 @@ static void autokeyframe_pose(
 
     ListBase dsources = {NULL, NULL};
 
-    /* add datasource override for the camera object */
+    /* Add data-source override for the camera object. */
     ANIM_relative_keyingset_add_source(&dsources, id, &RNA_PoseBone, pchan);
 
     /* only insert into active keyingset? */
     if (IS_AUTOKEY_FLAG(scene, ONLYKEYINGSET) && (active_ks)) {
-      /* run the active Keying Set on the current datasource */
+      /* Run the active Keying Set on the current data-source. */
       ANIM_apply_keyingset(
           C, &dsources, NULL, active_ks, MODIFYKEY_MODE_INSERT, anim_eval_context.eval_time);
     }
diff --git a/source/blender/editors/transform/transform_convert_object.c b/source/blender/editors/transform/transform_convert_object.c
index ee6cb391fdc..bcbac009948 100644
--- a/source/blender/editors/transform/transform_convert_object.c
+++ b/source/blender/editors/transform/transform_convert_object.c
@@ -749,7 +749,7 @@ static void autokeyframe_object(
     /* Get flags used for inserting keyframes. */
     flag = ANIM_get_keyframing_flags(scene, true);
 
-    /* add datasource override for the object */
+    /* Add data-source override for the object. */
     ANIM_relative_keyingset_add_source(&dsources, id, NULL, NULL);
 
     if (IS_AUTOKEY_FLAG(scene, ONLYKEYINGSET) && (active_ks)) {
diff --git a/source/blender/editors/transform/transform_snap_animation.c b/source/blender/editors/transform/transform_snap_animation.c
index be7fc65a6c2..08335924ddf 100644
--- a/source/blender/editors/transform/transform_snap_animation.c
+++ b/source/blender/editors/transform/transform_snap_animation.c
@@ -35,14 +35,14 @@
 #include "transform_snap.h"
 
 /* -------------------------------------------------------------------- */
-/** \name Snappint in Anim Editors
+/** \name Snapping in Anim Editors
  * \{ */
 
 /**
  * This function returns the snapping 'mode' for Animation Editors only.
  * We cannot use the standard snapping due to NLA-strip scaling complexities.
  *
- * TODO: these modifier checks should be key-mappable.
+ * TODO: these modifier checks should be accessible from the key-map.
  */
 short getAnimEdit_SnapMode(TransInfo *t)
 {
diff --git a/source/blender/io/collada/collada_internal.cpp b/source/blender/io/collada/collada_internal.cpp
index 355aa5c22f0..bd6f496c8ec 100644
--- a/source/blender/io/collada/collada_internal.cpp
+++ b/source/blender/io/collada/collada_internal.cpp
@@ -162,7 +162,7 @@ void UnitConverter::calculate_scale(Scene &sce)
  * Translation map.
  * Used to translate every COLLADA id to a valid id, no matter what "wrong" letters may be
  * included. Look at the IDREF XSD declaration for more.
- * Follows strictly the COLLADA XSD declaration which explicitly allows non-english chars,
+ * Follows strictly the COLLADA XSD declaration which explicitly allows non-English chars,
  * like special chars (e.g. micro sign), umlauts and so on.
  * The COLLADA spec also allows additional chars for member access ('.'), these
  * must obviously be removed too, otherwise they would be heavily misinterpreted.
diff --git a/source/blender/makesdna/DNA_cachefile_defaults.h b/source/blender/makesdna/DNA_cachefile_defaults.h
index 521b72567d4..74fbe5012ab 100644
--- a/source/blender/makesdna/DNA_cachefile_defaults.h
+++ b/source/blender/makesdna/DNA_cachefile_defaults.h
@@ -40,6 +40,8 @@
     .handle = NULL, \
     .handle_filepath[0] = '\0', \
     .handle_readers = NULL, \
+    .use_prefetch = 1, \
+    .prefetch_cache_size = 4096, \
   }
 
 /** \} */
diff --git a/source/blender/makesdna/DNA_cachefile_types.h b/source/blender/makesdna/DNA_cachefile_types.h
index ae4ade49be1..0f4c53a6e7e 100644
--- a/source/blender/makesdna/DNA_cachefile_types.h
+++ b/source/blender/makesdna/DNA_cachefile_types.h
@@ -101,7 +101,15 @@ typedef struct CacheFile {
    */
   char use_render_procedural;
 
-  char _pad1[7];
+  char _pad1[3];
+
+  /** Enable data prefetching when using the Cycles Procedural. */
+  char use_prefetch;
+
+  /** Size in megabytes for the prefetch cache used by the Cycles Procedural. */
+  int prefetch_cache_size;
+
+  char _pad2[7];
 
   char velocity_unit;
   /* Name of the velocity property in the archive. */
diff --git a/source/blender/makesrna/intern/rna_cachefile.c b/source/blender/makesrna/intern/rna_cachefile.c
index cb0a490417d..74d924b8937 100644
--- a/source/blender/makesrna/intern/rna_cachefile.c
+++ b/source/blender/makesrna/intern/rna_cachefile.c
@@ -150,6 +150,23 @@ static void rna_def_cachefile(BlenderRNA *brna)
                            "determine which file to use in a file sequence");
   RNA_def_property_update(prop, 0, "rna_CacheFile_update");
 
+  /* ----------------- Cache controls ----------------- */
+
+  prop = RNA_def_property(srna, "use_prefetch", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_ui_text(
+      prop,
+      "Use Prefetch",
+      "When enabled, the Cycles Procedural will preload animation data for faster updates");
+  RNA_def_property_update(prop, 0, "rna_CacheFile_update");
+
+  prop = RNA_def_property(srna, "prefetch_cache_size", PROP_INT, PROP_UNSIGNED);
+  RNA_def_property_ui_text(
+      prop,
+      "Prefetch Cache Size",
+      "Memory usage limit in megabytes for the Cycles Procedural cache, if the data does not "
+      "fit within the limit, rendering is aborted");
+  RNA_def_property_update(prop, 0, "rna_CacheFile_update");
+
   /* ----------------- Axis Conversion ----------------- */
 
   prop = RNA_def_property(srna, "forward_axis", PROP_ENUM, PROP_NONE);
diff --git a/source/blender/modifiers/intern/MOD_subsurf.c b/source/blender/modifiers/intern/MOD_subsurf.c
index ce427281db3..db0b769684e 100644
--- a/source/blender/modifiers/intern/MOD_subsurf.c
+++ b/source/blender/modifiers/intern/MOD_subsurf.c
@@ -358,13 +358,8 @@ static bool get_show_adaptive_options(const bContext *C, Panel *panel)
 
   /* Don't show adaptive options if the cycles experimental feature set is disabled. */
   Scene *scene = CTX_data_scene(C);
-  PointerRNA scene_ptr;
-  RNA_id_pointer_create(&scene->id, &scene_ptr);
-  if (BKE_scene_uses_cycles(scene)) {
-    PointerRNA cycles_ptr = RNA_pointer_get(&scene_ptr, "cycles");
-    if (RNA_enum_get(&cycles_ptr, "feature_set") != 1) { /* EXPERIMENTAL */
-      return false;
-    }
+  if (!BKE_scene_uses_cycles_experimental_features(scene)) {
+    return false;
   }
 
   return true;
diff --git a/source/blender/python/intern/bpy_app_icons.c b/source/blender/python/intern/bpy_app_icons.c
index 7cca3ae4700..acd809fb8d5 100644
--- a/source/blender/python/intern/bpy_app_icons.c
+++ b/source/blender/python/intern/bpy_app_icons.c
@@ -35,7 +35,7 @@
 /* We may want to load direct from file. */
 PyDoc_STRVAR(
     bpy_app_icons_new_triangles_doc,
-    ".. function:: new_triangles(range, coords, colors)"
+    ".. function:: new_triangles(range, coords, colors)\n"
     "\n"
     "   Create a new icon from triangle geometry.\n"
     "\n"
@@ -91,7 +91,7 @@ static PyObject *bpy_app_icons_new_triangles(PyObject *UNUSED(self), PyObject *a
 }
 
 PyDoc_STRVAR(bpy_app_icons_new_triangles_from_file_doc,
-             ".. function:: new_triangles_from_file(filename)"
+             ".. function:: new_triangles_from_file(filename)\n"
              "\n"
              "   Create a new icon from triangle geometry.\n"
              "\n"
@@ -122,7 +122,7 @@ static PyObject *bpy_app_icons_new_triangles_from_file(PyObject *UNUSED(self),
 }
 
 PyDoc_STRVAR(bpy_app_icons_release_doc,
-             ".. function:: release(icon_id)"
+             ".. function:: release(icon_id)\n"
              "\n"
              "   Release the icon.\n");
 static PyObject *bpy_app_icons_release(PyObject *UNUSED(self), PyObject *args, PyObject *kw)
diff --git a/source/blender/sequencer/intern/image_cache.c b/source/blender/sequencer/intern/image_cache.c
index 604c9900355..86bd840ce31 100644
--- a/source/blender/sequencer/intern/image_cache.c
+++ b/source/blender/sequencer/intern/image_cache.c
@@ -102,7 +102,7 @@
 /* <cache type>-<resolution X>x<resolution Y>-<rendersize>%(<view_id>)-<frame no>.dcf */
 #define DCACHE_FNAME_FORMAT "%d-%dx%d-%d%%(%d)-%d.dcf"
 #define DCACHE_IMAGES_PER_FILE 100
-#define DCACHE_CURRENT_VERSION 1
+#define DCACHE_CURRENT_VERSION 2
 #define COLORSPACE_NAME_MAX 64 /* XXX: defined in imb intern */
 
 typedef struct DiskCacheHeaderEntry {
@@ -496,24 +496,34 @@ static size_t deflate_imbuf_to_file(ImBuf *ibuf,
                                     int level,
                                     DiskCacheHeaderEntry *header_entry)
 {
-  if (ibuf->rect) {
-    return BLI_gzip_mem_to_file_at_pos(
-        ibuf->rect, header_entry->size_raw, file, header_entry->offset, level);
+  void *data = (ibuf->rect != NULL) ? (void *)ibuf->rect : (void *)ibuf->rect_float;
+
+  /* Apply compression if wanted, otherwise just write directly to the file. */
+  if (level > 0) {
+    return BLI_file_zstd_from_mem_at_pos(
+        data, header_entry->size_raw, file, header_entry->offset, level);
   }
 
-  return BLI_gzip_mem_to_file_at_pos(
-      ibuf->rect_float, header_entry->size_raw, file, header_entry->offset, level);
+  fseek(file, header_entry->offset, SEEK_SET);
+  return fwrite(data, 1, header_entry->size_raw, file);
 }
 
 static size_t inflate_file_to_imbuf(ImBuf *ibuf, FILE *file, DiskCacheHeaderEntry *header_entry)
 {
-  if (ibuf->rect) {
-    return BLI_ungzip_file_to_mem_at_pos(
-        ibuf->rect, header_entry->size_raw, file, header_entry->offset);
+  void *data = (ibuf->rect != NULL) ? (void *)ibuf->rect : (void *)ibuf->rect_float;
+  char header[4];
+  fseek(file, header_entry->offset, SEEK_SET);
+  if (fread(header, 1, sizeof(header), file) != sizeof(header)) {
+    return 0;
+  }
+
+  /* Check if the data is compressed or raw. */
+  if (BLI_file_magic_is_zstd(header)) {
+    return BLI_file_unzstd_to_mem_at_pos(data, header_entry->size_raw, file, header_entry->offset);
   }
 
-  return BLI_ungzip_file_to_mem_at_pos(
-      ibuf->rect_float, header_entry->size_raw, file, header_entry->offset);
+  fseek(file, header_entry->offset, SEEK_SET);
+  return fread(data, 1, header_entry->size_raw, file);
 }
 
 static bool seq_disk_cache_read_header(FILE *file, DiskCacheHeader *header)
diff --git a/source/blender/windowmanager/CMakeLists.txt b/source/blender/windowmanager/CMakeLists.txt
index b7fbb9bb82b..4d65726fe2b 100644
--- a/source/blender/windowmanager/CMakeLists.txt
+++ b/source/blender/windowmanager/CMakeLists.txt
@@ -48,10 +48,6 @@ set(INC
   ${CMAKE_BINARY_DIR}/source/blender/makesdna/intern
 )
 
-set(INC_SYS
-  ${ZLIB_INCLUDE_DIRS}
-)
-
 set(SRC
   intern/wm.c
   intern/wm_cursors.c
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 5cc361fc1bd..b9a3dd0c3fb 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -3471,8 +3471,8 @@ void wm_event_do_handlers(bContext *C)
             }
             CTX_wm_area_set(C, NULL);
 
-            /* NOTE: do not escape on WM_HANDLER_BREAK,
-             * mousemove needs handled for previous area. */
+            /* NOTE: do not escape on #WM_HANDLER_BREAK,
+             * mouse-move needs handled for previous area. */
           }
         }
 
diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index b53ad0ee927..f83511e76f0 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -28,11 +28,10 @@
  * winsock stuff.
  */
 #include <errno.h>
+#include <fcntl.h> /* for open flags (O_BINARY, O_RDONLY). */
 #include <stddef.h>
 #include <string.h>
 
-#include "zlib.h" /* wm_read_exotic() */
-
 #ifdef WIN32
 /* Need to include windows.h so _WIN32_IE is defined. */
 #  include <windows.h>
@@ -51,6 +50,7 @@
 
 #include "BLI_blenlib.h"
 #include "BLI_fileops_types.h"
+#include "BLI_filereader.h"
 #include "BLI_linklist.h"
 #include "BLI_math.h"
 #include "BLI_system.h"
@@ -481,53 +481,64 @@ static void wm_init_userdef(Main *bmain)
 /* intended to check for non-blender formats but for now it only reads blends */
 static int wm_read_exotic(const char *name)
 {
-  int len;
-  gzFile gzfile;
+  /* make sure we're not trying to read a directory.... */
+
+  int namelen = strlen(name);
+  if (namelen > 0 && ELEM(name[namelen - 1], '/', '\\')) {
+    return BKE_READ_EXOTIC_FAIL_PATH;
+  }
+
+  /* open the file. */
+  const int filedes = BLI_open(name, O_BINARY | O_RDONLY, 0);
+  if (filedes == -1) {
+    return BKE_READ_EXOTIC_FAIL_OPEN;
+  }
+
+  FileReader *rawfile = BLI_filereader_new_file(filedes);
+  if (rawfile == NULL) {
+    return BKE_READ_EXOTIC_FAIL_OPEN;
+  }
+
+  /* read the header (7 bytes are enough to identify all known types). */
   char header[7];
-  int retval;
+  if (rawfile->read(rawfile, header, sizeof(header)) != sizeof(header)) {
+    rawfile->close(rawfile);
+    return BKE_READ_EXOTIC_FAIL_FORMAT;
+  }
+  rawfile->seek(rawfile, 0, SEEK_SET);
 
-  /* make sure we're not trying to read a directory.... */
+  /* check for uncompressed .blend */
+  if (STREQLEN(header, "BLENDER", 7)) {
+    rawfile->close(rawfile);
+    return BKE_READ_EXOTIC_OK_BLEND;
+  }
 
-  len = strlen(name);
-  if (len > 0 && ELEM(name[len - 1], '/', '\\')) {
-    retval = BKE_READ_EXOTIC_FAIL_PATH;
+  /* check for compressed .blend */
+  FileReader *compressed_file = NULL;
+  if (BLI_file_magic_is_gzip(header)) {
+    /* In earlier versions of Blender (before 3.0), compressed files used Gzip instead of Zstd.
+     * While these files will no longer be written, there still needs to be reading support. */
+    compressed_file = BLI_filereader_new_gzip(rawfile);
+  }
+  else if (BLI_file_magic_is_zstd(header)) {
+    compressed_file = BLI_filereader_new_zstd(rawfile);
   }
-  else {
-    gzfile = BLI_gzopen(name, "rb");
-    if (gzfile == NULL) {
-      retval = BKE_READ_EXOTIC_FAIL_OPEN;
-    }
-    else {
-      len = gzread(gzfile, header, sizeof(header));
-      gzclose(gzfile);
-      if (len == sizeof(header) && STREQLEN(header, "BLENDER", 7)) {
-        retval = BKE_READ_EXOTIC_OK_BLEND;
-      }
-      else {
-        /* We may want to support loading other file formats
-         * from their header bytes or file extension.
-         * This used to be supported in the code below and may be added
-         * back at some point. */
-#if 0
-        WM_cursor_wait(true);
 
-        if (is_foo_format(name)) {
-          read_foo(name);
-          retval = BKE_READ_EXOTIC_OK_OTHER;
-        }
-        else
-#endif
-        {
-          retval = BKE_READ_EXOTIC_FAIL_FORMAT;
-        }
-#if 0
-        WM_cursor_wait(false);
-#endif
-      }
+  /* If a compression signature matches, try decompressing the start and check if it's a .blend */
+  if (compressed_file != NULL) {
+    size_t len = compressed_file->read(compressed_file, header, sizeof(header));
+    compressed_file->close(compressed_file);
+    if (len == sizeof(header) && STREQLEN(header, "BLENDER", 7)) {
+      return BKE_READ_EXOTIC_OK_BLEND;
     }
   }
+  else {
+    rawfile->close(rawfile);
+  }
+
+  /* Add check for future file formats here. */
 
-  return retval;
+  return BKE_READ_EXOTIC_FAIL_FORMAT;
 }
 
 /** \} */