3 lines while -> 1 line for loop

[ffmpeg] / libavcodec / mjpeg.c

diff --git a/libavcodec/mjpeg.c b/libavcodec/mjpeg.c
index f0634a041363fb5bbca56b79d049e9a25119237f..dffd9894694079c9c0422530b68f3a7d8890a396 100644 (file)
--- a/libavcodec/mjpeg.c
+++ b/libavcodec/mjpeg.c
@@ -1259,7 +1259,6 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
                         int component, int dc_index, int ac_index, int16_t *quant_matrix)
 {
     int code, i, j, level, val;
-    VLC *ac_vlc;
 
     /* DC coef */
     val = mjpeg_decode_dc(s, dc_index);
@@ -1271,9 +1270,8 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
     s->last_dc[component] = val;
     block[0] = val;
     /* AC coefs */
-    ac_vlc = &s->vlcs[1][ac_index];
     i = 0;
-    OPEN_READER(re, &s->gb)
+    {OPEN_READER(re, &s->gb)
     for(;;) {
         UPDATE_CACHE(re, &s->gb);
         GET_VLC(code, re, &s->gb, s->vlcs[1][ac_index].table, 9, 2)
@@ -1281,33 +1279,34 @@ static int decode_block(MJpegDecodeContext *s, DCTELEM *block,
         /* EOB */
         if (code == 0x10)
             break;
-        if (code == 0x100) {
-            i += 16;
-        } else {
-            i += ((unsigned)code) >> 4;
+        i += ((unsigned)code) >> 4;
+        if(code != 0x100){
             code &= 0xf;
-
-            UPDATE_CACHE(re, &s->gb)
-
-            if ((int32_t)GET_CACHE(re,&s->gb)<0) { //MSB=1
-                level =   NEG_USR32( GET_CACHE(re,&s->gb),code);
-            } else {
-                level = - NEG_USR32(~GET_CACHE(re,&s->gb),code);
+            if(code > MIN_CACHE_BITS - 16){
+                UPDATE_CACHE(re, &s->gb)
+            }
+            {
+                int cache=GET_CACHE(re,&s->gb);
+                int sign=(~cache)>>31;
+                level = (NEG_USR32(sign ^ cache,code) ^ sign) - sign;
             }
 
             LAST_SKIP_BITS(re, &s->gb, code)
 
-            if (i >= 64) {
+            if (i >= 63) {
+                if(i == 63){
+                    j = s->scantable.permutated[63];
+                    block[j] = level * quant_matrix[j];
+                    break;
+                }
                 dprintf("error count: %d\n", i);
                 return -1;
             }
             j = s->scantable.permutated[i];
             block[j] = level * quant_matrix[j];
-            if (i >= 63)
-                break;
         }
     }
-    CLOSE_READER(re, &s->gb)
+    CLOSE_READER(re, &s->gb)}
 
     return 0;
 }