Add function to load only screenshot from snapshot file

snapshot.cpp

@@ -1069,26 +1069,9 @@ int S9xUnfreezeGameMem (const uint8 *buf, uint32 bufSize)
 	return result;
 }
 
-bool8 S9xUnfreezeGame (const char *filename)
+void S9xMessageFromResult(int result, const char* base)
 {
-	STREAM	stream = NULL;
+    switch(result)
-	char	drive[_MAX_DRIVE + 1], dir[_MAX_DIR + 1], def[_MAX_FNAME + 1], ext[_MAX_EXT + 1];
-
-	const char	*base = S9xBasename(filename);
-
-	_splitpath(filename, drive, dir, def, ext);
-	S9xResetSaveTimer(!strcmp(ext, "oops") || !strcmp(ext, "oop") || !strcmp(ext, ".oops") || !strcmp(ext, ".oop"));
-
-	if (S9xOpenSnapshotFile(filename, TRUE, &stream))
-	{
-		int	result;
-
-		result = S9xUnfreezeFromStream(stream);
-		S9xCloseSnapshotFile(stream);
-
-		if (result != SUCCESS)
-		{
-			switch (result)
     {
         case WRONG_FORMAT:
             S9xMessage(S9X_ERROR, S9X_WRONG_FORMAT, SAVE_ERR_WRONG_FORMAT);
@@ -1116,7 +1099,28 @@ bool8 S9xUnfreezeGame (const char *filename)
             S9xMessage(S9X_ERROR, S9X_ROM_NOT_FOUND, String);
             break;
     }
+}
 
+bool8 S9xUnfreezeGame (const char *filename)
+{
+	STREAM	stream = NULL;
+	char	drive[_MAX_DRIVE + 1], dir[_MAX_DIR + 1], def[_MAX_FNAME + 1], ext[_MAX_EXT + 1];
+
+	const char	*base = S9xBasename(filename);
+
+	_splitpath(filename, drive, dir, def, ext);
+	S9xResetSaveTimer(!strcmp(ext, "oops") || !strcmp(ext, "oop") || !strcmp(ext, ".oops") || !strcmp(ext, ".oop"));
+
+	if (S9xOpenSnapshotFile(filename, TRUE, &stream))
+	{
+		int	result;
+
+		result = S9xUnfreezeFromStream(stream);
+		S9xCloseSnapshotFile(stream);
+
+		if (result != SUCCESS)
+		{
+            S9xMessageFromResult(result, base);
 			return (FALSE);
 		}
 
@@ -1141,6 +1145,34 @@ bool8 S9xUnfreezeGame (const char *filename)
 	return (FALSE);
 }
 
+bool8 S9xUnfreezeScreenshot(const char *filename, uint16 **image_buffer, int &width, int &height)
+{
+    STREAM	stream = NULL;
+
+    const char	*base = S9xBasename(filename);
+
+    if(S9xOpenSnapshotFile(filename, TRUE, &stream))
+    {
+        int	result;
+
+        result = S9xUnfreezeScreenshotFromStream(stream, image_buffer, width, height);
+        S9xCloseSnapshotFile(stream);
+
+        if(result != SUCCESS)
+        {
+            S9xMessageFromResult(result, base);
+            return (FALSE);
+        }
+
+        return (TRUE);
+    }
+
+    sprintf(String, SAVE_ERR_SAVE_NOT_FOUND, base);
+    S9xMessage(S9X_INFO, S9X_FREEZE_FILE_INFO, String);
+
+    return (FALSE);
+}
+
 void S9xFreezeToStream (STREAM stream)
 {
 	char	buffer[8192];
@@ -1801,6 +1833,96 @@ int S9xUnfreezeFromStream (STREAM stream)
 	return (result);
 }
 
+// load screenshot from file, allocating memory for it
+int S9xUnfreezeScreenshotFromStream(STREAM stream, uint16 **image_buffer, int &width, int &height)
+{
+    int		result = SUCCESS;
+    int		version, len;
+    char	buffer[PATH_MAX + 1];
+
+    len = strlen(SNAPSHOT_MAGIC) + 1 + 4 + 1;
+    if(READ_STREAM(buffer, len, stream) != (unsigned int)len)
+        return (WRONG_FORMAT);
+
+    if(strncmp(buffer, SNAPSHOT_MAGIC, strlen(SNAPSHOT_MAGIC)) != 0)
+        return (WRONG_FORMAT);
+
+    version = atoi(&buffer[strlen(SNAPSHOT_MAGIC) + 1]);
+    if(version > SNAPSHOT_VERSION)
+        return (WRONG_VERSION);
+
+    result = UnfreezeBlock(stream, "NAM", (uint8 *)buffer, PATH_MAX);
+    if(result != SUCCESS)
+        return (result);
+
+    uint8	*local_screenshot = NULL;
+
+    // skip all blocks until screenshot
+    SkipBlockWithName(stream, "CPU");
+    SkipBlockWithName(stream, "REG");
+    SkipBlockWithName(stream, "PPU");
+    SkipBlockWithName(stream, "DMA");
+    SkipBlockWithName(stream, "VRA");
+    SkipBlockWithName(stream, "RAM");
+    SkipBlockWithName(stream, "SRA");
+    SkipBlockWithName(stream, "FIL");
+    SkipBlockWithName(stream, "SND");
+    SkipBlockWithName(stream, "CTL");
+    SkipBlockWithName(stream, "TIM");
+    SkipBlockWithName(stream, "SFX");
+    SkipBlockWithName(stream, "SA1");
+    SkipBlockWithName(stream, "SAR");
+    SkipBlockWithName(stream, "DP1");
+    SkipBlockWithName(stream, "DP2");
+    SkipBlockWithName(stream, "DP4");
+    SkipBlockWithName(stream, "CX4");
+    SkipBlockWithName(stream, "ST0");
+    SkipBlockWithName(stream, "OBC");
+    SkipBlockWithName(stream, "OBM");
+    SkipBlockWithName(stream, "S71");
+    SkipBlockWithName(stream, "SRT");
+    SkipBlockWithName(stream, "CLK");
+    SkipBlockWithName(stream, "BSX");
+    SkipBlockWithName(stream, "MSU");
+    result = UnfreezeStructCopy(stream, "SHO", &local_screenshot, SnapScreenshot, COUNT(SnapScreenshot), version);
+
+
+    if(result == SUCCESS && local_screenshot)
+    {
+        SnapshotScreenshotInfo	*ssi = new SnapshotScreenshotInfo;
+
+        UnfreezeStructFromCopy(ssi, SnapScreenshot, COUNT(SnapScreenshot), local_screenshot, version);
+
+        width = min(ssi->Width, IMAGE_WIDTH);
+        height = min(ssi->Height, IMAGE_HEIGHT);
+
+        *image_buffer = (uint16 *)malloc(width * height * sizeof(uint16));
+
+        uint8	*rowpix = ssi->Data;
+        uint16	*screen = (*image_buffer);
+
+        for(int y = 0; y < height; y++, screen += width)
+        {
+            for(int x = 0; x < width; x++)
+            {
+                uint32	r, g, b;
+
+                r = *(rowpix++);
+                g = *(rowpix++);
+                b = *(rowpix++);
+
+                screen[x] = BUILD_PIXEL(r, g, b);
+            }
+        }
+
+        delete ssi;
+    }
+
+    if(local_screenshot)		delete[] local_screenshot;
+
+    return (result);
+}
+
 static int FreezeSize (int size, int type)
 {
 	switch (type)

snapshot.h

@@ -31,5 +31,7 @@ bool8 S9xUnfreezeGame (const char *);
 int S9xUnfreezeGameMem (const uint8 *,uint32);
 void S9xFreezeToStream (STREAM);
 int	 S9xUnfreezeFromStream (STREAM);
+bool8 S9xUnfreezeScreenshot(const char *filename, uint16 **image_buffer, int &width, int &height);
+int S9xUnfreezeScreenshotFromStream(STREAM stream, uint16 **image_buffer, int &width, int &height);
 
 #endif