diff -r 000000000000 -r 6474c204b198 media/libvpx/vp9/decoder/vp9_read_bit_buffer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/media/libvpx/vp9/decoder/vp9_read_bit_buffer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#ifndef VP9_DECODER_VP9_READ_BIT_BUFFER_H_
+#define VP9_DECODER_VP9_READ_BIT_BUFFER_H_
+
+#include <limits.h>
+
+#include "vpx/vpx_integer.h"
+
+typedef void (*vp9_rb_error_handler)(void *data, size_t bit_offset);
+
+struct vp9_read_bit_buffer {
+  const uint8_t *bit_buffer;
+  const uint8_t *bit_buffer_end;
+  size_t bit_offset;
+
+  void *error_handler_data;
+  vp9_rb_error_handler error_handler;
+};
+
+static size_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) {
+  return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0);
+}
+
+static int vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) {
+  const size_t off = rb->bit_offset;
+  const size_t p = off / CHAR_BIT;
+  const int q = CHAR_BIT - 1 - (int)off % CHAR_BIT;
+  if (rb->bit_buffer + p >= rb->bit_buffer_end) {
+    rb->error_handler(rb->error_handler_data, rb->bit_offset);
+    return 0;
+  } else {
+    const int bit = (rb->bit_buffer[p] & (1 << q)) >> q;
+    rb->bit_offset = off + 1;
+    return bit;
+  }
+}
+
+static int vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) {
+  int value = 0, bit;
+  for (bit = bits - 1; bit >= 0; bit--)
+    value |= vp9_rb_read_bit(rb) << bit;
+  return value;
+}
+
+static int vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb,
+                                      int bits) {
+  const int value = vp9_rb_read_literal(rb, bits);
+  return vp9_rb_read_bit(rb) ? -value : value;
+}
+
+#endif  // VP9_DECODER_VP9_READ_BIT_BUFFER_H_