shorten: split reading of file header into a separate functions

libavcodec/shorten.c

@@ -273,44 +273,9 @@ static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_siz
     }
 }
 
-
-static int shorten_decode_frame(AVCodecContext *avctx,
-        void *data, int *data_size,
-        AVPacket *avpkt)
+static int read_header(ShortenContext *s)
 {
-    const uint8_t *buf = avpkt->data;
-    int buf_size = avpkt->size;
-    ShortenContext *s = avctx->priv_data;
-    int i, input_buf_size = 0;
-    int16_t *samples = data;
-    if(s->max_framesize == 0){
-        s->max_framesize= 1024; // should hopefully be enough for the first header
-        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
-    }
-
-    if(1 && s->max_framesize){//FIXME truncated
-        buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
-        input_buf_size= buf_size;
-
-        if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
-            //                printf("memmove\n");
-            memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
-            s->bitstream_index=0;
-        }
-        memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
-        buf= &s->bitstream[s->bitstream_index];
-        buf_size += s->bitstream_size;
-        s->bitstream_size= buf_size;
-
-        if(buf_size < s->max_framesize){
-            *data_size = 0;
-            return input_buf_size;
-        }
-    }
-    init_get_bits(&s->gb, buf, buf_size*8);
-    skip_bits(&s->gb, s->bitindex);
-    if (!s->blocksize)
-    {
+    int i;
     int maxnlpc = 0;
     /* shorten signature */
     if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
@@ -367,11 +332,55 @@ static int shorten_decode_frame(AVCodecContext *avctx,
     for (i=0; i<s->header_size; i++)
         s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 
-        if (decode_wave_header(avctx, s->header, s->header_size) < 0)
+    if (decode_wave_header(s->avctx, s->header, s->header_size) < 0)
         return -1;
 
     s->cur_chan = 0;
     s->bitshift = 0;
+
+    return 0;
+}
+
+static int shorten_decode_frame(AVCodecContext *avctx,
+        void *data, int *data_size,
+        AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    int buf_size = avpkt->size;
+    ShortenContext *s = avctx->priv_data;
+    int i, input_buf_size = 0;
+    int16_t *samples = data;
+    if(s->max_framesize == 0){
+        s->max_framesize= 1024; // should hopefully be enough for the first header
+        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
+    }
+
+    if(1 && s->max_framesize){//FIXME truncated
+        buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
+        input_buf_size= buf_size;
+
+        if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
+            //                printf("memmove\n");
+            memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
+            s->bitstream_index=0;
+        }
+        memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
+        buf= &s->bitstream[s->bitstream_index];
+        buf_size += s->bitstream_size;
+        s->bitstream_size= buf_size;
+
+        if(buf_size < s->max_framesize){
+            *data_size = 0;
+            return input_buf_size;
+        }
+    }
+    init_get_bits(&s->gb, buf, buf_size*8);
+    skip_bits(&s->gb, s->bitindex);
+    if (!s->blocksize)
+    {
+        int ret;
+        if ((ret = read_header(s)) < 0)
+            return ret;
     }
     else
     {