Add filesystem override API.

src/raylib.h

@@ -855,6 +855,14 @@ typedef enum {
 // Callbacks to be implemented by users
 typedef void (*TraceLogCallback)(int logType, const char *text, va_list args);
 
+// Filesystem override implemented by users.
+typedef struct FilesystemOverride {
+  unsigned char *(*loadFileData)(const char *fileName, unsigned int *bytesRead);
+  void (*saveFileData)(const char *fileName, void *data, unsigned int bytesToWrite);
+  char *(*loadFileText)(const char *fileName);
+  void (*saveFileText)(const char *fileName, char *text);
+} FilesystemOverride;
+
 #if defined(__cplusplus)
 extern "C" {            // Prevents name mangling of functions
 #endif
@@ -953,6 +961,7 @@ RLAPI void TakeScreenshot(const char *fileName);                  // Takes a scr
 RLAPI int GetRandomValue(int min, int max);                       // Returns a random value between min and max (both included)
 
 // Files management functions
+RLAPI void SetFilesystemOverride(FilesystemOverride override);    // Set filesystem functions override.
 RLAPI unsigned char *LoadFileData(const char *fileName, unsigned int *bytesRead);     // Load file data as byte array (read)
 RLAPI void SaveFileData(const char *fileName, void *data, unsigned int bytesToWrite); // Save data to file from byte array (write)
 RLAPI char *LoadFileText(const char *fileName);                   // Load text data from file (read), returns a '\0' terminated string
@@ -1164,7 +1173,7 @@ RLAPI void ImageDrawCircle(Image *dst, int centerX, int centerY, int radius, Col
 RLAPI void ImageDrawCircleV(Image *dst, Vector2 center, int radius, Color color);                        // Draw circle within an image (Vector version)
 RLAPI void ImageDrawRectangle(Image *dst, int posX, int posY, int width, int height, Color color);       // Draw rectangle within an image
 RLAPI void ImageDrawRectangleV(Image *dst, Vector2 position, Vector2 size, Color color);                 // Draw rectangle within an image (Vector version)
-RLAPI void ImageDrawRectangleRec(Image *dst, Rectangle rec, Color color);                                // Draw rectangle within an image 
+RLAPI void ImageDrawRectangleRec(Image *dst, Rectangle rec, Color color);                                // Draw rectangle within an image
 RLAPI void ImageDrawRectangleLines(Image *dst, Rectangle rec, int thick, Color color);                   // Draw rectangle lines within an image
 RLAPI void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec, Color tint);             // Draw a source image within a destination image (tint applied to source)
 RLAPI void ImageDrawText(Image *dst, const char *text, int posX, int posY, int fontSize, Color color);   // Draw text (using default font) within an image (destination)

src/utils.c

@@ -63,6 +63,9 @@ static int logTypeLevel = LOG_INFO;                     // Minimum log type leve
 static int logTypeExit = LOG_ERROR;                     // Log type that exits
 static TraceLogCallback logCallback = NULL;             // Log callback function pointer
 
+// Filesystem function override.
+static FilesystemOverride fsOverride = { NULL, NULL, NULL, NULL };
+
 #if defined(PLATFORM_ANDROID)
 static AAssetManager *assetManager = NULL;              // Android assets manager pointer
 static const char *internalDataPath = NULL;             // Android internal data path
@@ -164,6 +167,12 @@ void TraceLog(int logType, const char *text, ...)
 #endif  // SUPPORT_TRACELOG
 }
 
+// Set filesystem functions override.
+void SetFilesystemOverride(FilesystemOverride override)
+{
+    fsOverride = override;
+}
+
 // Load data from file into a buffer
 unsigned char *LoadFileData(const char *fileName, unsigned int *bytesRead)
 {
@@ -172,6 +181,13 @@ unsigned char *LoadFileData(const char *fileName, unsigned int *bytesRead)
 
     if (fileName != NULL)
     {
+        if (fsOverride.loadFileData) {
+            data = fsOverride.loadFileData(fileName, bytesRead);
+
+            if (data)
+                return data;
+        }
+
         FILE *file = fopen(fileName, "rb");
 
         if (file != NULL)
@@ -209,6 +225,11 @@ void SaveFileData(const char *fileName, void *data, unsigned int bytesToWrite)
 {
     if (fileName != NULL)
     {
+        if (fsOverride.saveFileData) {
+            fsOverride.saveFileData(fileName, data, bytesToWrite);
+            return;
+        }
+
         FILE *file = fopen(fileName, "wb");
 
         if (file != NULL)
@@ -234,6 +255,13 @@ char *LoadFileText(const char *fileName)
 
     if (fileName != NULL)
     {
+        if (fsOverride.loadFileText) {
+            text = fsOverride.loadFileText(fileName);
+
+            if (text)
+                return text;
+        }
+
         FILE *textFile = fopen(fileName, "rt");
 
         if (textFile != NULL)
@@ -275,6 +303,11 @@ void SaveFileText(const char *fileName, char *text)
 {
     if (fileName != NULL)
     {
+        if (fsOverride.saveFileText) {
+            fsOverride.saveFileText(fileName, text);
+            return;
+        }
+
         FILE *file = fopen(fileName, "wt");
 
         if (file != NULL)
@@ -318,7 +351,7 @@ FILE *android_fopen(const char *fileName, const char *mode)
         // NOTE: AAsset provides access to read-only asset
         AAsset *asset = AAssetManager_open(assetManager, fileName, AASSET_MODE_UNKNOWN);
 
-        if (asset != NULL) 
+        if (asset != NULL)
         {
             // Return pointer to file in the assets
             return funopen(asset, android_read, android_write, android_seek, android_close);