193a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org/* 293a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * Copyright (c) 2013 The WebM project authors. All Rights Reserved. 393a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * 493a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * Use of this source code is governed by a BSD-style license 593a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * that can be found in the LICENSE file in the root of the source 693a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * tree. An additional intellectual property rights grant can be found 793a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * in the file PATENTS. All contributing project authors may 893a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org * be found in the AUTHORS file in the root of the source tree. 993a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org */ 1093a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org#include "vp9/decoder/vp9_read_bit_buffer.h" 1193a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org 1293a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.orgsize_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) { 1388b47b29cc274dd19cddc37c1ce1834d97df282efgalligan@chromium.org return (rb->bit_offset + CHAR_BIT - 1) / CHAR_BIT; 1493a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org} 1593a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org 1693a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.orgint vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) { 1793a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org const size_t off = rb->bit_offset; 1893a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org const size_t p = off / CHAR_BIT; 1993a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org const int q = CHAR_BIT - 1 - (int)off % CHAR_BIT; 2093a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org if (rb->bit_buffer + p >= rb->bit_buffer_end) { 2193a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org rb->error_handler(rb->error_handler_data); 2293a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org return 0; 2393a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org } else { 2493a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org const int bit = (rb->bit_buffer[p] & (1 << q)) >> q; 2593a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org rb->bit_offset = off + 1; 2693a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org return bit; 2793a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org } 2893a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org} 2993a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org 3093a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.orgint vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) { 3193a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org int value = 0, bit; 3293a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org for (bit = bits - 1; bit >= 0; bit--) 3393a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org value |= vp9_rb_read_bit(rb) << bit; 3493a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org return value; 3593a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org} 3693a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org 3793a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.orgint vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb, 3893a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org int bits) { 3993a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org const int value = vp9_rb_read_literal(rb, bits); 4093a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org return vp9_rb_read_bit(rb) ? -value : value; 4193a74791c8e808ea76001ee07693aa2a5fdd3500johannkoenig@chromium.org} 42