gpujpegtool: if invalid raw ext passed, print avail

eg. `gpujpegtool -s 1920x1080 -e null.bla out.jpg`, but as with HEAD~4,
the .bla file can be an existent file as well, which will convert (with
warnings, however).

Author: MartinPulec

src/gpujpeg_common.c

@@ -420,6 +420,16 @@ gpujpeg_image_get_file_format(const char* filename)
         PRINTF("\nUse \"help.tst\" (eg. `gpujpegtool help.tst null.jpg`) for test image usage).\n");
         return GPUJPEG_IMAGE_FILE_UNKNOWN;
     }
+    if ( strcmp(filename, "rawhelp") == 0 ) {
+        PRINTF("Recognized raw extensions:");
+        for ( unsigned i = 0; i < sizeof extensions / sizeof extensions[0]; i++ ) {
+            if ( extensions[i].format > GPUJPEG_IMAGE_FILE_RAW ) {
+                PRINTF(" %s", extensions[i].ext);
+            }
+        }
+        PRINTF("\n");
+        return GPUJPEG_IMAGE_FILE_UNKNOWN;
+    }
 
     const char * ext = strrchr(filename, '.');
     if ( ext == NULL )

src/main.c

@@ -565,6 +565,7 @@ main(int argc, char *argv[])
             enum gpujpeg_image_file_format output_format = gpujpeg_image_get_file_format(output);
             if ( !GPUJPEG_IMAGE_FORMAT_IS_RAW(input_format) ) {
                 fprintf(stderr, "[Warning] Encoder input file [%s] should be raw image (" RAW_EXTS ")!\n", input);
+                gpujpeg_image_get_file_format("rawhelp");
                 if ( input_format & GPUJPEG_IMAGE_FILE_JPEG ) {
                     return -1;
                 }
@@ -711,6 +712,7 @@ main(int argc, char *argv[])
             }
             if ( !GPUJPEG_IMAGE_FORMAT_IS_RAW(output_format) ) {
                 fprintf(stderr, "[Warning] Decoder output file [%s] should be raw image (" RAW_EXTS ")!\n", output);
+                gpujpeg_image_get_file_format("rawhelp");
                 if ( output_format & GPUJPEG_IMAGE_FILE_JPEG ) {
                     ret = EXIT_FAILURE; continue;
                 }