From 289761adddd30fc486b2db2e3fae00eacdfc1e3a Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Sat, 4 Feb 2006 22:26:04 +0000
Subject: [PATCH] If there's an error loading an image, seek back to the start
 of the image.

---
 IMG_bmp.c |  3 +++
 IMG_gif.c |  8 +++++++-
 IMG_jpg.c | 15 ++++++++++-----
 IMG_lbm.c | 10 ++++++++--
 IMG_pcx.c | 10 ++++++++--
 IMG_png.c | 29 +++++++++++++++++++++--------
 IMG_pnm.c |  9 +++++++--
 IMG_tga.c | 30 +++++++++++++++++++-----------
 IMG_tif.c | 15 ++++++++++++---
 IMG_xcf.c | 28 +++++++++++++++++-----------
 IMG_xpm.c | 10 ++++++++--
 IMG_xxx.c | 21 ++++++++++++++++++++-
 12 files changed, 140 insertions(+), 48 deletions(-)

diff --git a/IMG_bmp.c b/IMG_bmp.c
index e70a532b..e5892b91 100644
--- a/IMG_bmp.c
+++ b/IMG_bmp.c
@@ -422,6 +422,9 @@ static SDL_Surface *LoadBMP_RW (SDL_RWops *src, int freesrc)
 	}
 done:
 	if ( was_error ) {
+		if ( src ) {
+			SDL_RWseek(src, fp_offset, SEEK_SET);
+		}
 		if ( surface ) {
 			SDL_FreeSurface(surface);
 		}
diff --git a/IMG_gif.c b/IMG_gif.c
index 5e30b6cf..8bceb4f4 100644
--- a/IMG_gif.c
+++ b/IMG_gif.c
@@ -151,6 +151,7 @@ static Image *ReadImage(SDL_RWops * src, int len, int height, int,
 Image *
 IMG_LoadGIF_RW(SDL_RWops *src)
 {
+    int start;
     unsigned char buf[16];
     unsigned char c;
     unsigned char localColorMap[3][MAXCOLORMAPSIZE];
@@ -163,8 +164,10 @@ IMG_LoadGIF_RW(SDL_RWops *src)
     Image *image = NULL;
 
     if ( src == NULL ) {
-        goto done;
+	return NULL;
     }
+    start = SDL_RWtell(src);
+
     if (!ReadOK(src, buf, 6)) {
 	RWSetMsg("error reading magic number");
         goto done;
@@ -262,6 +265,9 @@ IMG_LoadGIF_RW(SDL_RWops *src)
 #endif
 
 done:
+    if ( image == NULL ) {
+        SDL_RWseek(src, start, SEEK_SET);
+    }
     return image;
 }
 
diff --git a/IMG_jpg.c b/IMG_jpg.c
index 4916ac53..80325b71 100644
--- a/IMG_jpg.c
+++ b/IMG_jpg.c
@@ -202,6 +202,7 @@ static void output_no_message(j_common_ptr cinfo)
 /* Load a JPEG type image from an SDL datasource */
 SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
 {
+	int start;
 	struct jpeg_decompress_struct cinfo;
 	JSAMPROW rowptr[1];
 	SDL_Surface *volatile surface = NULL;
@@ -211,6 +212,7 @@ SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
 
 	/* Create a decompression structure and load the JPEG header */
 	cinfo.err = jpeg_std_error(&jerr.errmgr);
@@ -219,8 +221,11 @@ SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
 	if(setjmp(jerr.escape)) {
 		/* If we get here, libjpeg found an error */
 		jpeg_destroy_decompress(&cinfo);
+		if ( surface != NULL ) {
+			SDL_FreeSurface(surface);
+		}
+		SDL_RWseek(src, start, SEEK_SET);
 		IMG_SetError("JPEG loading error");
-		SDL_FreeSurface(surface);
 		return NULL;
 	}
 
@@ -249,8 +254,10 @@ SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
 #endif
 				   0);
 	if ( surface == NULL ) {
+		jpeg_destroy_decompress(&cinfo);
+		SDL_RWseek(src, start, SEEK_SET);
 		IMG_SetError("Out of memory");
-		goto done;
+		return NULL;
 	}
 
 	/* Decompress the image */
@@ -261,10 +268,8 @@ SDL_Surface *IMG_LoadJPG_RW(SDL_RWops *src)
 		jpeg_read_scanlines(&cinfo, rowptr, (JDIMENSION) 1);
 	}
 	jpeg_finish_decompress(&cinfo);
-
-	/* Clean up and return */
-done:
 	jpeg_destroy_decompress(&cinfo);
+
 	return(surface);
 }
 
diff --git a/IMG_lbm.c b/IMG_lbm.c
index 578f6c7c..3a710460 100644
--- a/IMG_lbm.c
+++ b/IMG_lbm.c
@@ -84,6 +84,7 @@ int IMG_isLBM( SDL_RWops *src )
 
 SDL_Surface *IMG_LoadLBM_RW( SDL_RWops *src )
 {
+	int start;
 	SDL_Surface *Image;
 	Uint8       id[4], pbm, colormap[MAXCOLORS*3], *MiniBuf, *ptr, count, color, msk;
 	Uint32      size, bytesloaded, nbcolors;
@@ -102,6 +103,8 @@ SDL_Surface *IMG_LoadLBM_RW( SDL_RWops *src )
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
+
 	if ( !SDL_RWread( src, id, 4, 1 ) )
 	{
 		error="error reading IFF chunk";
@@ -469,9 +472,12 @@ SDL_Surface *IMG_LoadLBM_RW( SDL_RWops *src )
 
 	if ( error )
 	{
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( Image ) {
+			SDL_FreeSurface( Image );
+			Image = NULL;
+		}
 		IMG_SetError( error );
-		SDL_FreeSurface( Image );
-		Image = NULL;
 	}
 
 	return( Image );
diff --git a/IMG_pcx.c b/IMG_pcx.c
index 52ba3d4c..25b7bc95 100644
--- a/IMG_pcx.c
+++ b/IMG_pcx.c
@@ -87,6 +87,7 @@ int IMG_isPCX(SDL_RWops *src)
 /* Load a PCX type image from an SDL datasource */
 SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)
 {
+	int start;
 	struct PCXheader pcxh;
 	Uint32 Rmask;
 	Uint32 Gmask;
@@ -103,6 +104,8 @@ SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
+
 	if ( ! SDL_RWread(src, &pcxh, sizeof(pcxh), 1) ) {
 		error = "file truncated";
 		goto done;
@@ -235,9 +238,12 @@ SDL_Surface *IMG_LoadPCX_RW(SDL_RWops *src)
 done:
 	free(buf);
 	if ( error ) {
-		SDL_FreeSurface(surface);
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( surface ) {
+			SDL_FreeSurface(surface);
+			surface = NULL;
+		}
 		IMG_SetError(error);
-		surface = NULL;
 	}
 	return(surface);
 }
diff --git a/IMG_png.c b/IMG_png.c
index ed763ceb..ab81fba1 100644
--- a/IMG_png.c
+++ b/IMG_png.c
@@ -99,6 +99,8 @@ static void png_read_data(png_structp ctx, png_bytep area, png_size_t size)
 }
 SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 {
+	int start;
+	const char *error;
 	SDL_Surface *volatile surface;
 	png_structp png_ptr;
 	png_infop info_ptr;
@@ -118,22 +120,24 @@ SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
 
 	/* Initialize the data we will clean up when we're done */
+	error = NULL;
 	png_ptr = NULL; info_ptr = NULL; row_pointers = NULL; surface = NULL;
 
 	/* Create the PNG loading context structure */
 	png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
 					  NULL,NULL,NULL);
 	if (png_ptr == NULL){
-		IMG_SetError("Couldn't allocate memory for PNG file or incompatible PNG dll");
+		error = "Couldn't allocate memory for PNG file or incompatible PNG dll";
 		goto done;
 	}
 
 	 /* Allocate/initialize the memory for image information.  REQUIRED. */
 	info_ptr = png_create_info_struct(png_ptr);
 	if (info_ptr == NULL) {
-		IMG_SetError("Couldn't create image information for PNG file");
+		error = "Couldn't create image information for PNG file";
 		goto done;
 	}
 
@@ -142,7 +146,7 @@ SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 	 * set up your own error handlers in png_create_read_struct() earlier.
 	 */
 	if ( setjmp(png_ptr->jmpbuf) ) {
-		IMG_SetError("Error reading the PNG file.");
+		error = "Error reading the PNG file.";
 		goto done;
 	}
 
@@ -222,7 +226,7 @@ SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 	surface = SDL_AllocSurface(SDL_SWSURFACE, width, height,
 			bit_depth*info_ptr->channels, Rmask,Gmask,Bmask,Amask);
 	if ( surface == NULL ) {
-		IMG_SetError("Out of memory");
+		error = "Out of memory";
 		goto done;
 	}
 
@@ -239,9 +243,7 @@ SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 	/* Create the array of pointers to image data */
 	row_pointers = (png_bytep*) malloc(sizeof(png_bytep)*height);
 	if ( (row_pointers == NULL) ) {
-		IMG_SetError("Out of memory");
-		SDL_FreeSurface(surface);
-		surface = NULL;
+		error = "Out of memory";
 		goto done;
 	}
 	for (row = 0; row < (int)height; row++) {
@@ -281,11 +283,22 @@ SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
 	}
 
 done:	/* Clean up and return */
-	png_destroy_read_struct(&png_ptr, info_ptr ? &info_ptr : (png_infopp)0,
+	if ( png_ptr ) {
+		png_destroy_read_struct(&png_ptr,
+		                        info_ptr ? &info_ptr : (png_infopp)0,
 								(png_infopp)0);
+	}
 	if ( row_pointers ) {
 		free(row_pointers);
 	}
+	if ( error ) {
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( surface ) {
+			SDL_FreeSurface(surface);
+			surface = NULL;
+		}
+		IMG_SetError(error);
+	}
 	return(surface); 
 }
 
diff --git a/IMG_pnm.c b/IMG_pnm.c
index bcef664c..671eb252 100644
--- a/IMG_pnm.c
+++ b/IMG_pnm.c
@@ -105,6 +105,7 @@ static int ReadNumber(SDL_RWops *src)
 
 SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src)
 {
+	int start;
 	SDL_Surface *surface = NULL;
 	int width, height;
 	int maxval, y, bpl;
@@ -121,6 +122,7 @@ SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src)
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
 
 	SDL_RWread(src, magic, 2, 1);
 	kind = magic[1] - '1';
@@ -229,9 +231,12 @@ SDL_Surface *IMG_LoadPNM_RW(SDL_RWops *src)
 done:
 	free(buf);
 	if(error) {
-		SDL_FreeSurface(surface);
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( surface ) {
+			SDL_FreeSurface(surface);
+			surface = NULL;
+		}
 		IMG_SetError(error);
-		surface = NULL;
 	}
 	return(surface);
 }
diff --git a/IMG_tga.c b/IMG_tga.c
index 6481bccb..b83b2ee1 100644
--- a/IMG_tga.c
+++ b/IMG_tga.c
@@ -87,6 +87,7 @@ enum tga_type {
 SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 {
     int start;
+    const char *error = NULL;
     struct TGAheader hdr;
     int rle = 0;
     int alpha = 0;
@@ -94,7 +95,7 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
     int grey = 0;
     int ckey = -1;
     int ncols, w, h;
-    SDL_Surface *img;
+    SDL_Surface *img = NULL;
     Uint32 rmask, gmask, bmask, amask;
     Uint8 *dst;
     int i;
@@ -107,10 +108,12 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
         /* The error message has been set in SDL_RWFromFile */
         return NULL;
     }
-
     start = SDL_RWtell(src);
-    if(!SDL_RWread(src, &hdr, sizeof(hdr), 1))
+
+    if(!SDL_RWread(src, &hdr, sizeof(hdr), 1)) {
+        error = "Error reading TGA data";
 	goto error;
+    }
     ncols = LE16(hdr.cmap_len);
     switch(hdr.type) {
     case TGA_TYPE_RLE_INDEXED:
@@ -118,7 +121,7 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 	/* fallthrough */
     case TGA_TYPE_INDEXED:
 	if(!hdr.has_cmap || hdr.pixel_bits != 8 || ncols > 256)
-	    goto error;
+	    goto unsupported;
 	indexed = 1;
 	break;
 
@@ -134,7 +137,7 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 	/* fallthrough */
     case TGA_TYPE_BW:
 	if(hdr.pixel_bits != 8)
-	    goto error;
+	    goto unsupported;
 	/* Treat greyscale as 8bpp indexed images */
 	indexed = grey = 1;
 	break;
@@ -195,6 +198,10 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
     img = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h,
 			       bpp * 8,
 			       rmask, gmask, bmask, amask);
+    if(img == NULL) {
+        error = "Out of memory";
+        goto error;
+    }
 
     if(hdr.has_cmap) {
 	int palsiz = ncols * ((hdr.cmap_bits + 7) >> 3);
@@ -303,14 +310,15 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
     }
     return img;
 
-error:
-    SDL_RWseek(src, start, SEEK_SET);
-    IMG_SetError("Error reading TGA data");
-    return NULL;
-
 unsupported:
+    error = "Unsupported TGA format";
+
+error:
     SDL_RWseek(src, start, SEEK_SET);
-    IMG_SetError("unsupported TGA format");
+    if ( img ) {
+        SDL_FreeSurface(img);
+    }
+    IMG_SetError(error);
     return NULL;
 }
 
diff --git a/IMG_tif.c b/IMG_tif.c
index a4f58d79..b12a86a5 100644
--- a/IMG_tif.c
+++ b/IMG_tif.c
@@ -109,6 +109,7 @@ int IMG_isTIF(SDL_RWops* src)
 
 SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)
 {
+	int start;
 	TIFF* tiff;
 	SDL_Surface* surface = NULL;
 	Uint32 img_width, img_height;
@@ -120,12 +121,13 @@ SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
+	start = SDL_RWtell(src);
 
 	/* turn off memory mapped access with the m flag */
 	tiff = TIFFClientOpen("SDL_image", "rm", (thandle_t)src, 
 		tiff_read, tiff_write, tiff_seek, tiff_close, tiff_size, NULL, NULL);
 	if(!tiff)
-		return NULL;
+		goto error;
 
 	/* Retrieve the dimensions of the image from the TIFF tags */
 	TIFFGetField(tiff, TIFFTAG_IMAGEWIDTH, &img_width);
@@ -138,10 +140,10 @@ SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)
 	surface = SDL_AllocSurface(SDL_SWSURFACE, img_width, img_height, 32,
 		Rmask, Gmask, Bmask, Amask);
 	if(!surface)
-		return NULL;
+		goto error;
 	
 	if(!TIFFReadRGBAImage(tiff, img_width, img_height, surface->pixels, 0))
-		return NULL;
+		goto error;
 
 	/* libtiff loads the image upside-down, flip it back */
 	half = img_height / 2;
@@ -160,6 +162,13 @@ SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)
 	TIFFClose(tiff);
 	
 	return surface;
+
+error:
+	SDL_RWseek(src, start, SEEK_SET);
+	if ( surface ) {
+		SDL_FreeSurface(surface);
+	}
+	return NULL;
 }
 
 #else
diff --git a/IMG_xcf.c b/IMG_xcf.c
index 73433bc9..2adc8202 100644
--- a/IMG_xcf.c
+++ b/IMG_xcf.c
@@ -671,12 +671,15 @@ int do_layer_surface (SDL_Surface * surface, SDL_RWops * src, xcf_header * head,
   return 0;
 }
 
-SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
+SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src)
+{
+  int start;
+  const char *error = NULL;
   SDL_Surface *surface, *lays;
   xcf_header * head;
   xcf_layer  * layer;
   xcf_channel ** channel;
-  int read_error, chnls, i, offsets;
+  int chnls, i, offsets;
   Uint32 offset, fp;
 
   unsigned char * (* load_tile) (SDL_RWops *, Uint32, int, int, int);
@@ -685,10 +688,10 @@ SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
     /* The error message has been set in SDL_RWFromFile */
     return NULL;
   }
+  start = SDL_RWtell(src);
 
   /* Initialize the data we will clean up when we're done */
   surface = NULL;
-  read_error = 0;
 
   head = read_xcf_header (src);
 
@@ -710,7 +713,7 @@ SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
 			     0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);
 
   if ( surface == NULL ) {
-    IMG_SetError("Out of memory");
+    error = "Out of memory";
     goto done;
   }
 
@@ -728,7 +731,7 @@ SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
 			  0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);
 
   if ( lays == NULL ) {
-    IMG_SetError("Out of memory");
+    error = "Out of memory";
     goto done;
   }
 
@@ -775,7 +778,7 @@ SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
 			   0x00FF0000,0x0000FF00,0x000000FF,0xFF000000);
 
     if (chs == NULL) {
-      IMG_SetError("Out of memory");
+      error = "Out of memory";
       goto done;
     }
     for (i = 0; i < chnls; i++) {
@@ -790,12 +793,15 @@ SDL_Surface *IMG_LoadXCF_RW(SDL_RWops *src) {
     SDL_FreeSurface (chs);
   }
 
- done:
+done:
   free_xcf_header (head);
-  if ( read_error ) {
-    SDL_FreeSurface(surface);
-    IMG_SetError("Error reading XCF data");
-    surface = NULL;
+  if ( error ) {
+    SDL_RWseek(src, start, SEEK_SET);
+    if ( surface ) {
+      SDL_FreeSurface(surface);
+      surface = NULL;
+    }
+    IMG_SetError(error);
   }
 
   return(surface);
diff --git a/IMG_xpm.c b/IMG_xpm.c
index 79a3c8f0..f7cd1ec7 100644
--- a/IMG_xpm.c
+++ b/IMG_xpm.c
@@ -310,6 +310,7 @@ do {							\
 /* read XPM from either array or RWops */
 static SDL_Surface *load_xpm(char **xpm, SDL_RWops *src)
 {
+	int start;
 	SDL_Surface *image = NULL;
 	int index;
 	int x, y;
@@ -327,6 +328,8 @@ static SDL_Surface *load_xpm(char **xpm, SDL_RWops *src)
 	linebuf = NULL;
 	buflen = 0;
 
+	start = SDL_RWtell(src);
+
 	if(xpm)
 		xpmlines = &xpm;
 
@@ -452,8 +455,11 @@ static SDL_Surface *load_xpm(char **xpm, SDL_RWops *src)
 
 done:
 	if(error) {
-		SDL_FreeSurface(image);
-		image = NULL;
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( image ) {
+			SDL_FreeSurface(image);
+			image = NULL;
+		}
 		IMG_SetError(error);
 	}
 	free(keystrings);
diff --git a/IMG_xxx.c b/IMG_xxx.c
index 590af52b..38f82f52 100644
--- a/IMG_xxx.c
+++ b/IMG_xxx.c
@@ -38,6 +38,9 @@ int IMG_isXXX(SDL_RWops *src)
 
 	start = SDL_RWtell(src);
 	is_XXX = 0;
+
+	/* Detect the image here */
+
 	SDL_RWseek(src, start, SEEK_SET);
 	return(is_XXX);
 }
@@ -45,11 +48,27 @@ int IMG_isXXX(SDL_RWops *src)
 /* Load a XXX type image from an SDL datasource */
 SDL_Surface *IMG_LoadXXX_RW(SDL_RWops *src)
 {
+	int start;
+	const char *error = NULL;
+	SDL_Surface *surface = NULL;
+
 	if ( !src ) {
 		/* The error message has been set in SDL_RWFromFile */
 		return NULL;
 	}
-	return(NULL);
+	start = SDL_RWtell(src);
+
+	/* Load the image here */
+
+	if ( error ) {
+		SDL_RWseek(src, start, SEEK_SET);
+		if ( surface ) {
+			SDL_FreeSurface(surface);
+			surface = NULL;
+		}
+		IMG_SetError(error);
+	}
+	return surface;
 }
 
 #else