Fixed image type functions so they seek back to where they started

libsdl-org · Feb 4, 2006 · b2ed3ce · b2ed3ce
1 parent 9802897
commit b2ed3ce
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Showing 13 changed files with 103 additions and 60 deletions.
diff --git a/IMG.c b/IMG.c
@@ -96,7 +96,7 @@ static int IMG_string_equals(const char *str1, const char *str2)
 /* Load an image from an SDL datasource, optionally specifying the type */
 SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)
 {
-	int i, start;
+	int i;
 	SDL_Surface *image;
 
 	/* Make sure there is something to do.. */
@@ -114,11 +114,9 @@ SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)
 	}
 
 	/* Detect the type of image being loaded */
-	start = SDL_RWtell(src);
 	image = NULL;
 	for ( i=0; i < ARRAYSIZE(supported); ++i ) {
 		if(supported[i].is) {
-			SDL_RWseek(src, start, SEEK_SET);
 			if(!supported[i].is(src))
 				continue;
 		} else {
@@ -131,7 +129,6 @@ SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)
 		fprintf(stderr, "IMGLIB: Loading image as %s\n",
 			supported[i].type);
 #endif
-		SDL_RWseek(src, start, SEEK_SET);
 		image = supported[i].load(src);
 		if(freesrc)
 			SDL_RWclose(src);

diff --git a/IMG_bmp.c b/IMG_bmp.c
@@ -34,15 +34,18 @@
 /* See if an image is contained in a data source */
 int IMG_isBMP(SDL_RWops *src)
 {
+	int start;
 	int is_BMP;
 	char magic[2];
 
+	start = SDL_RWtell(src);
 	is_BMP = 0;
-	if ( SDL_RWread(src, magic, 2, 1) ) {
+	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
 		if ( strncmp(magic, "BM", 2) == 0 ) {
 			is_BMP = 1;
 		}
 	}
+	SDL_RWseek(src, start, SEEK_SET);
 	return(is_BMP);
 }
 

diff --git a/IMG_gif.c b/IMG_gif.c
@@ -34,17 +34,20 @@
 /* See if an image is contained in a data source */
 int IMG_isGIF(SDL_RWops *src)
 {
+	int start;
 	int is_GIF;
 	char magic[6];
 
+	start = SDL_RWtell(src);
 	is_GIF = 0;
-	if ( SDL_RWread(src, magic, 6, 1) ) {
+	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
 		if ( (strncmp(magic, "GIF", 3) == 0) &&
 		     ((memcmp(magic + 3, "87a", 3) == 0) ||
 		      (memcmp(magic + 3, "89a", 3) == 0)) ) {
 			is_GIF = 1;
 		}
 	}
+	SDL_RWseek(src, start, SEEK_SET);
 	return(is_GIF);
 }
 

diff --git a/IMG_jpg.c b/IMG_jpg.c
@@ -40,9 +40,11 @@
 /* See if an image is contained in a data source */
 int IMG_isJPG(SDL_RWops *src)
 {
+	int start;
 	int is_JPG;
 	Uint8 magic[4];
 
+	start = SDL_RWtell(src);
 	is_JPG = 0;
 	if ( SDL_RWread(src, magic, 2, 1) ) {
 		if ( (magic[0] == 0xFF) && (magic[1] == 0xD8) ) {
@@ -61,6 +63,7 @@ int IMG_isJPG(SDL_RWops *src)
 			}
 		}
 	}
+	SDL_RWseek(src, start, SEEK_SET);
 	return(is_JPG);
 }
 

diff --git a/IMG_lbm.c b/IMG_lbm.c
@@ -63,11 +63,13 @@ typedef struct
 
 int IMG_isLBM( SDL_RWops *src )
 {
+	int start;
 	int   is_LBM;
 	Uint8 magic[4+4+4];
 
+	start = SDL_RWtell(src);
 	is_LBM = 0;
-	if ( SDL_RWread( src, magic, 4+4+4, 1 ) )
+	if ( SDL_RWread( src, magic, sizeof(magic), 1 ) )
 	{
 		if ( !memcmp( magic, "FORM", 4 ) &&
 			( !memcmp( magic + 8, "PBM ", 4 ) ||
@@ -76,6 +78,7 @@ int IMG_isLBM( SDL_RWops *src )
 			is_LBM = 1;
 		}
 	}
+	SDL_RWseek(src, start, SEEK_SET);
 	return( is_LBM );
 }
 

diff --git a/IMG_pcx.c b/IMG_pcx.c
@@ -64,12 +64,14 @@ struct PCXheader {
 /* See if an image is contained in a data source */
 int IMG_isPCX(SDL_RWops *src)
 {
+	int start;
 	int is_PCX;
 	const int ZSoft_Manufacturer = 10;
 	const int PC_Paintbrush_Version = 5;
 	const int PCX_RunLength_Encoding = 1;
 	struct PCXheader pcxh;
 
+	start = SDL_RWtell(src);
 	is_PCX = 0;
 	if ( SDL_RWread(src, &pcxh, sizeof(pcxh), 1) == 1 ) {
 		if ( (pcxh.Manufacturer == ZSoft_Manufacturer) &&
@@ -78,6 +80,7 @@ int IMG_isPCX(SDL_RWops *src)
 			is_PCX = 1;
 		}
 	}
+	SDL_RWseek(src, start, SEEK_SET);
 	return(is_PCX);
 }
 

diff --git a/IMG_png.c b/IMG_png.c
@@ -76,14 +76,17 @@
 /* See if an image is contained in a data source */
 int IMG_isPNG(SDL_RWops *src)
 {
-   unsigned char buf[PNG_BYTES_TO_CHECK];
-
-   /* Read in the signature bytes */
-   if (SDL_RWread(src, buf, 1, PNG_BYTES_TO_CHECK) != PNG_BYTES_TO_CHECK)
-      return 0;
-
-   /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature. */
-   return( !png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
+	int start;
+	int is_PNG;
+	unsigned char buf[PNG_BYTES_TO_CHECK];
+
+	start = SDL_RWtell(src);
+	is_PNG = 0;
+	if ( SDL_RWread(src, buf, 1, PNG_BYTES_TO_CHECK) == PNG_BYTES_TO_CHECK ) {
+		is_PNG = (png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK) == 0);
+	}
+	SDL_RWseek(src, start, SEEK_SET);
+	return(is_PNG);
 }
 
 /* Load a PNG type image from an SDL datasource */

diff --git a/IMG_pnm.c b/IMG_pnm.c
@@ -42,19 +42,28 @@
 /* See if an image is contained in a data source */
 int IMG_isPNM(SDL_RWops *src)
 {
+	int start;
+	int is_PNM;
 	char magic[2];
 
-	/*
-	 * PNM magic signatures:
-	 * P1	PBM, ascii format
-	 * P2	PGM, ascii format
-	 * P3	PPM, ascii format
-	 * P4	PBM, binary format
-	 * P5	PGM, binary format
-	 * P6	PPM, binary format
-	 */
-	return (SDL_RWread(src, magic, 2, 1)
-		&& magic[0] == 'P' && magic[1] >= '1' && magic[1] <= '6');
+	start = SDL_RWtell(src);
+	is_PNM = 0;
+	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
+		/*
+		 * PNM magic signatures:
+		 * P1	PBM, ascii format
+		 * P2	PGM, ascii format
+		 * P3	PPM, ascii format
+		 * P4	PBM, binary format
+		 * P5	PGM, binary format
+		 * P6	PPM, binary format
+		 */
+		if ( magic[0] == 'P' && magic[1] >= '1' && magic[1] <= '6' ) {
+			is_PNM = 1;
+		}
+	}
+	SDL_RWseek(src, start, SEEK_SET);
+	return(is_PNM);
 }
 
 /* read a non-negative integer from the source. return -1 upon error */

diff --git a/IMG_tga.c b/IMG_tga.c
@@ -83,14 +83,10 @@ enum tga_type {
 #define LE16(p) ((p)[0] + ((p)[1] << 8))
 #define SETLE16(p, v) ((p)[0] = (v), (p)[1] = (v) >> 8)
 
-static void unsupported(void)
-{
-    IMG_SetError("unsupported TGA format");
-}
-
 /* Load a TGA type image from an SDL datasource */
 SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 {
+    int start;
     struct TGAheader hdr;
     int rle = 0;
     int alpha = 0;
@@ -112,6 +108,7 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
         return NULL;
     }
 
+    start = SDL_RWtell(src);
     if(!SDL_RWread(src, &hdr, sizeof(hdr), 1))
 	goto error;
     ncols = LE16(hdr.cmap_len);
@@ -143,17 +140,15 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 	break;
 
     default:
-        unsupported();
-	return NULL;
+        goto unsupported;
     }
 
     bpp = (hdr.pixel_bits + 7) >> 3;
     rmask = gmask = bmask = amask = 0;
     switch(hdr.pixel_bits) {
     case 8:
 	if(!indexed) {
-	    unsupported();
-	    return NULL;
+            goto unsupported;
 	}
 	break;
 
@@ -185,14 +180,12 @@ SDL_Surface *IMG_LoadTGA_RW(SDL_RWops *src)
 	break;
 
     default:
-	unsupported();
-	return NULL;
+        goto unsupported;
     }
 
     if((hdr.flags & TGA_INTERLEAVE_MASK) != TGA_INTERLEAVE_NONE
        || hdr.flags & TGA_ORIGIN_RIGHT) {
-	unsupported();
-	return NULL;
+        goto unsupported;
     }
 
     SDL_RWseek(src, hdr.infolen, SEEK_CUR); /* skip info field */
@@ -311,8 +304,14 @@ 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:
+    SDL_RWseek(src, start, SEEK_SET);
+    IMG_SetError("unsupported TGA format");
+    return NULL;
 }
 
 #else

diff --git a/IMG_tif.c b/IMG_tif.c
@@ -77,9 +77,14 @@ static toff_t tiff_size(thandle_t fd)
 
 int IMG_isTIF(SDL_RWops* src)
 {
+	int start;
+	int is_TIF;
 	TIFF* tiff;
 	TIFFErrorHandler prev_handler;
 
+	start = SDL_RWtell(src);
+	is_TIF = 0;
+
 	/* Suppress output from libtiff */
 	prev_handler = TIFFSetErrorHandler(NULL);
 
@@ -92,13 +97,14 @@ int IMG_isTIF(SDL_RWops* src)
 	TIFFSetErrorHandler(prev_handler);
 
 	/* If it's not a TIFF, then tiff will be NULL. */
-	if(!tiff)
-		return 0;
+	if ( tiff ) {
+		is_TIF = 1;
 
-	/* Free up any dynamically allocated memory libtiff uses */
-	TIFFClose(tiff);
-
-	return 1;
+		/* Free up any dynamically allocated memory libtiff uses */
+		TIFFClose(tiff);
+	}
+	SDL_RWseek(src, start, SEEK_SET);
+	return(is_TIF);
 }
 
 SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)

diff --git a/IMG_xcf.c b/IMG_xcf.c
@@ -209,18 +209,21 @@ typedef unsigned char * (* load_tile_type) (SDL_RWops *, Uint32, int, int, int);
 
 
 /* See if an image is contained in a data source */
-int IMG_isXCF(SDL_RWops *src) {
-  int is_XCF;
-  char magic[14];
-
-  is_XCF = 0;
-  if ( SDL_RWread(src, magic, 14, 1) ) {
-    if (strncmp(magic, "gimp xcf ", 9) == 0) {
-      is_XCF = 1;
-    }
-  }
-
-  return(is_XCF);
+int IMG_isXCF(SDL_RWops *src)
+{
+	int start;
+	int is_XCF;
+	char magic[14];
+
+	start = SDL_RWtell(src);
+	is_XCF = 0;
+	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
+		if (strncmp(magic, "gimp xcf ", 9) == 0) {
+			is_XCF = 1;
+		}
+	}
+	SDL_RWseek(src, start, SEEK_SET);
+	return(is_XCF);
 }
 
 static char * read_string (SDL_RWops * src) {

diff --git a/IMG_xpm.c b/IMG_xpm.c
@@ -57,10 +57,19 @@
 /* See if an image is contained in a data source */
 int IMG_isXPM(SDL_RWops *src)
 {
+	int start;
+	int is_XPM;
 	char magic[9];
 
-	return (SDL_RWread(src, magic, sizeof(magic), 1)
-		&& memcmp(magic, "/* XPM */", 9) == 0);
+	start = SDL_RWtell(src);
+	is_XPM = 0;
+	if ( SDL_RWread(src, magic, sizeof(magic), 1) ) {
+		if ( memcmp(magic, "/* XPM */", sizeof(magic)) == 0 ) {
+			is_XPM = 1;
+		}
+	}
+	SDL_RWseek(src, start, SEEK_SET);
+	return(is_XPM);
 }
 
 /* Hash table to look up colors from pixel strings */

diff --git a/IMG_xxx.c b/IMG_xxx.c
@@ -33,10 +33,12 @@
 /* See if an image is contained in a data source */
 int IMG_isXXX(SDL_RWops *src)
 {
+	int start;
 	int is_XXX;
 
+	start = SDL_RWtell(src);
 	is_XXX = 0;
-
+	SDL_RWseek(src, start, SEEK_SET);
 	return(is_XXX);
 }