1 files changed, 85 insertions, 0 deletions
diff --git a/Source/Internal/cachefile.cpp b/Source/Internal/cachefile.cpp
new file mode 100644
index 00000000..f255a905
--- /dev/null
+++ b/Source/Internal/cachefile.cpp
@@ -0,0 +1,85 @@
+//-----------------------------------------------------------------------------
+//           Name: cachefile.cpp
+//      Developer: Wolfire Games LLC
+//    Description:
+//        License: Read below
+//-----------------------------------------------------------------------------
+//
+//   Copyright 2022 Wolfire Games LLC
+//
+//   Licensed under the Apache License, Version 2.0 (the "License");
+//   you may not use this file except in compliance with the License.
+//   You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+//
+//-----------------------------------------------------------------------------
+#include "cachefile.h"
+
+#include <Internal/checksum.h>
+#include <Internal/datemodified.h>
+#include <Internal/filesystem.h>
+
+bool CacheFile::CheckForCache(const std::string &path, const std::string &suffix, std::string *load_path, uint16_t *checksum) {
+    ModID modsource;
+    return CheckForCache(path,suffix,load_path,&modsource,checksum);
+}
+
+bool CacheFile::CheckForCache(const std::string &path, const std::string &suffix, std::string *load_path, ModID *load_modsource, uint16_t *checksum){
+    std::string cache_str = path + suffix;
+
+    const int kMaxPaths = 5;
+    char abs_cache_paths[kPathSize * kMaxPaths];
+    ModID cache_modsources[kMaxPaths];
+    char abs_base_paths[kPathSize * kMaxPaths];
+    int num_cache_paths_found = FindFilePaths(cache_str.c_str(), abs_cache_paths, kPathSize, kMaxPaths, kAnyPath, false, NULL, cache_modsources );
+    int num_base_paths_found = FindFilePaths(path.c_str(), abs_base_paths, kPathSize, kMaxPaths, kAnyPath, false, NULL, NULL );
+
+    char* cache_path = &abs_cache_paths[0];
+    ModID cache_modsource = cache_modsources[0];
+    int64_t latest_cache_date_modified = -1;
+    if(num_cache_paths_found > 0){
+        for(int path_index=0; path_index<num_cache_paths_found; ++path_index){
+            char* curr_path = &abs_cache_paths[kPathSize * path_index];
+            ModID curr_modsource = cache_modsources[path_index];
+            int64_t date_modified = GetDateModifiedInt64(curr_path);
+            if(date_modified > latest_cache_date_modified){
+                latest_cache_date_modified = date_modified;
+                cache_path = curr_path;
+                cache_modsource = curr_modsource;
+            }
+        }        
+    }
+
+    char* base_path = &abs_base_paths[0];
+    int64_t latest_base_date_modified = -1;
+    if(num_base_paths_found > 0){
+        for(int path_index=0; path_index<num_base_paths_found; ++path_index){
+            char* curr_path = &abs_base_paths[kPathSize * path_index];
+            int64_t date_modified = GetDateModifiedInt64(curr_path);
+            if(date_modified > latest_base_date_modified){
+                latest_base_date_modified = date_modified;
+                base_path = curr_path;
+            }
+        }        
+    }
+
+    if(latest_base_date_modified != -1){
+        *checksum = Checksum(base_path);
+    } else {
+        *checksum = 0;
+    }
+
+    if(latest_cache_date_modified != -1){
+        *load_path = cache_path;
+        *load_modsource = cache_modsource;
+        return true;
+    }
+    return false;
+}