1 files changed, 76 insertions, 0 deletions
diff --git a/media/libvpx/vp8/decoder/dboolhuff.c b/media/libvpx/vp8/decoder/dboolhuff.c
new file mode 100644
index 000000000..b874d4c46
--- /dev/null
+++ b/media/libvpx/vp8/decoder/dboolhuff.c
@@ -0,0 +1,76 @@
+/*
+ *  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 "vp8/common/common.h"
+
+int vp8dx_start_decode(BOOL_DECODER *br,
+                       const unsigned char *source,
+                       unsigned int source_sz,
+                       vpx_decrypt_cb decrypt_cb,
+                       void *decrypt_state)
+{
+    br->user_buffer_end = source+source_sz;
+    br->user_buffer     = source;
+    br->value    = 0;
+    br->count    = -8;
+    br->range    = 255;
+    br->decrypt_cb = decrypt_cb;
+    br->decrypt_state = decrypt_state;
+
+    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 = br->user_buffer;
+    VP8_BD_VALUE value = br->value;
+    int count = br->count;
+    int shift = VP8_BD_VALUE_SIZE - CHAR_BIT - (count + CHAR_BIT);
+    size_t bytes_left = br->user_buffer_end - bufptr;
+    size_t bits_left = bytes_left * CHAR_BIT;
+    int x = (int)(shift + CHAR_BIT - bits_left);
+    int loop_end = 0;
+    unsigned char decrypted[sizeof(VP8_BD_VALUE) + 1];
+
+    if (br->decrypt_cb) {
+        size_t n = MIN(sizeof(decrypted), bytes_left);
+        br->decrypt_cb(br->decrypt_state, bufptr, decrypted, (int)n);
+        bufptr = decrypted;
+    }
+
+    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;
+            ++bufptr;
+            ++br->user_buffer;
+            shift -= CHAR_BIT;
+        }
+    }
+
+    br->value = value;
+    br->count = count;
+}