Fix incorrect increment in sgidec.c

[ffmpeg] / libavcodec / 4xm.c

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index e57ce90df6e96c757b78e433a9f28fa5a2bf3392..d665436844f04c656da40fea4990065e28f74740 100644 (file)
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -643,9 +643,17 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
     int x, y, x2, y2;
     const int width= f->avctx->width;
     const int height= f->avctx->height;
+    const int mbs = (FFALIGN(width, 16) >> 4) * (FFALIGN(height, 16) >> 4);
     uint16_t *dst= (uint16_t*)f->current_picture.data[0];
     const int stride= f->current_picture.linesize[0]>>1;
     const uint8_t *buf_end = buf + length;
+    GetByteContext g3;
+
+    if(length < mbs * 8) {
+        av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");
+        return AVERROR_INVALIDDATA;
+    }
+    bytestream2_init(&g3, buf, length);
 
     for(y=0; y<height; y+=16){
         for(x=0; x<width; x+=16){
@@ -654,8 +662,8 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
                 return -1;
             memset(color, 0, sizeof(color));
 //warning following is purely guessed ...
-            color[0]= bytestream_get_le16(&buf);
-            color[1]= bytestream_get_le16(&buf);
+            color[0]= bytestream2_get_le16u(&g3);
+            color[1]= bytestream2_get_le16u(&g3);
 
             if(color[0]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 1\n");
             if(color[1]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 2\n");
@@ -663,7 +671,7 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
             color[2]= mix(color[0], color[1]);
             color[3]= mix(color[1], color[0]);
 
-            bits= bytestream_get_le32(&buf);
+            bits= bytestream2_get_le32u(&g3);
             for(y2=0; y2<16; y2++){
                 for(x2=0; x2<16; x2++){
                     int index= 2*(x2>>2) + 8*(y2>>2);
@@ -672,7 +680,7 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
             }
             dst+=16;
         }
-        dst += 16*stride - width;
+        dst += 16 * stride - x;
     }
 
     return 0;
@@ -823,7 +831,7 @@ static int decode_frame(AVCodecContext *avctx,
 
     if(frame_4cc == AV_RL32("ifr2")){
         p->pict_type= AV_PICTURE_TYPE_I;
-        if(decode_i2_frame(f, buf-4, frame_size+4) < 0){
+        if(decode_i2_frame(f, buf-4, frame_size + 4) < 0) {
             av_log(f->avctx, AV_LOG_ERROR, "decode i2 frame failed\n");
             return -1;
         }