Description:

source/libvpx/vp8/decoder/dboolhuff.c

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 
 #include "dboolhuff.h"
-#include "vpx_ports/mem.h"
-#include "vpx_mem/vpx_mem.h"
 
 int vp8dx_start_decode(BOOL_DECODER *br,
                        const unsigned char *source,
                        unsigned int source_sz)
 {
     br->user_buffer_end = source+source_sz;
     br->user_buffer     = source;
     br->value    = 0;
     br->count    = -8;
     br->range    = 255;
 
     if (source_sz && !source)
         return 1;
 
     /* Populate the buffer */
     vp8dx_bool_decoder_fill(br);
 
     return 0;
 }
 
-
 void vp8dx_bool_decoder_fill(BOOL_DECODER *br)
 {
-    const unsigned char *bufptr;
-    const unsigned char *bufend;
-    VP8_BD_VALUE         value;
-    int                  count;
-    bufend = br->user_buffer_end;
-    bufptr = br->user_buffer;
-    value = br->value;
-    count = br->count;
+    const unsigned char *bufptr = br->user_buffer;
+    const unsigned char *bufend = br->user_buffer_end;
+    VP8_BD_VALUE value = br->value;
+    int count = br->count;
+    int shift = VP8_BD_VALUE_SIZE - 8 - (count + 8);
+    size_t bits_left = (bufend - bufptr)*CHAR_BIT;
+    int x = (int)(shift + CHAR_BIT - bits_left);
+    int loop_end = 0;
 
-    VP8DX_BOOL_DECODER_FILL(count, value, bufptr, bufend);
+    if(x >= 0)
+    {
+        count += VP8_LOTS_OF_BITS;
+        loop_end = x;
+    }
+
+    if (x < 0 || bits_left)
+    {
+        while(shift >= loop_end)
+        {
+            count += CHAR_BIT;
+            value |= (VP8_BD_VALUE)*bufptr++ << shift;
+            shift -= CHAR_BIT;
+        }
+    }
 
     br->user_buffer = bufptr;
     br->value = value;
     br->count = count;
 }