Index: source/libvpx/vp9/decoder/vp9_read_bit_buffer.c |
=================================================================== |
--- source/libvpx/vp9/decoder/vp9_read_bit_buffer.c (revision 0) |
+++ source/libvpx/vp9/decoder/vp9_read_bit_buffer.c (revision 0) |
@@ -0,0 +1,41 @@ |
+/* |
+ * 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. |
+ */ |
+#include "vp9/decoder/vp9_read_bit_buffer.h" |
+ |
+size_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) { |
+ return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0); |
+} |
+ |
+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); |
+ return 0; |
+ } else { |
+ const int bit = (rb->bit_buffer[p] & (1 << q)) >> q; |
+ rb->bit_offset = off + 1; |
+ return bit; |
+ } |
+} |
+ |
+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; |
+} |
+ |
+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; |
+} |