diff options
Diffstat (limited to 'source/blender/blenloader/intern/undofile.c')
-rw-r--r-- | source/blender/blenloader/intern/undofile.c | 95 |
1 files changed, 95 insertions, 0 deletions
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; +} |