Fix for bug #3886

Basically the check for a type of jpeg was messed up.
I added a imb_is_a_jpeg function since I was working on that bit and
it makes it a little more similar to the other filetypes.

I also changed a switch statement that had the same loop for all
cases, just moved the loop outside of the switch statement.

Kent

source/blender/imbuf/intern/IMB_jpeg.h

@@ -43,6 +43,7 @@
 struct ImBuf;
 struct jpeg_compress_struct;
 
+int imb_is_a_jpeg(unsigned char *mem);
 int imb_savejpeg(struct ImBuf * ibuf, char * name, int flags);
 struct ImBuf * imb_ibJpegImageFromFilename (char * filename, int flags);
 struct ImBuf * imb_ibJpegImageFromMemory (unsigned char * buffer, int size, int flags);

source/blender/imbuf/intern/jpeg.c

@@ -72,6 +72,12 @@ static int jpeg_failed = FALSE;
 static int jpeg_default_quality;
 static int ibuf_ftype;
 
+int imb_is_a_jpeg(unsigned char *mem) {
+
+	if ((mem[0]== 0xFF) && (mem[1] == 0xD8))return 1;
+	return 0;
+}
+
 static void jpeg_error (j_common_ptr cinfo)
 {
 	/* Always display the message */
@@ -280,25 +286,21 @@ static ImBuf * ibJpegImageFromCinfo(struct jpeg_decompress_struct * cinfo, int f
 				}
 				buffer = row_pointer[0];
 				
-				switch(depth) {
-					case 1:
-						for (x = ibuf->x; x > 0; x--) {
+				for (x=ibuf->x; x >0; x--) {
+					switch(depth) {
+						case 1:
 							rect[3] = 255;
 							rect[0] = rect[1] = rect[2] = *buffer++;
 							rect += 4;
-						}
-						break;
-					case 3:
-						for (x = ibuf->x; x > 0; x--) {
+							break;
+						case 3:
 							rect[3] = 255;
 							rect[0] = *buffer++;
 							rect[1] = *buffer++;
 							rect[2] = *buffer++;
 							rect += 4;
-						}
-						break;
-					case 4:
-						for (x = ibuf->x; x > 0; x--) {
+							break;
+						case 4:
 							r = *buffer++;
 							g = *buffer++;
 							b = *buffer++;
@@ -326,7 +328,7 @@ static ImBuf * ibJpegImageFromCinfo(struct jpeg_decompress_struct * cinfo, int f
 							rect[1] = g;
 							rect[0] = r;
 							rect += 4;
-						}
+					}
 				}
 			}
 			jpeg_finish_decompress(cinfo);

source/blender/imbuf/intern/readimage.c

@@ -96,7 +96,7 @@ ImBuf *IMB_ibImageFromMemory(int *mem, int size, int flags) {
 	} else {
 		if ((GS(mem) == IMAGIC) || (GSS(mem) == IMAGIC)){
 			return (imb_loadiris((uchar *) mem, flags));
-		} else if ((BIG_LONG(mem[0]) & 0xfffffff0) == 0xffd8ffe0) {
+		} else if (imb_is_a_jpeg((uchar *)mem)) {
 			return (imb_ibJpegImageFromMemory((uchar *)mem, size, flags));
 		}