1233d2500723e5594f3e7c70896ffeeef32b9c950ywan/* 2233d2500723e5594f3e7c70896ffeeef32b9c950ywan * Copyright (c) 2013 The WebM project authors. All Rights Reserved. 3233d2500723e5594f3e7c70896ffeeef32b9c950ywan * 4233d2500723e5594f3e7c70896ffeeef32b9c950ywan * Use of this source code is governed by a BSD-style license 5233d2500723e5594f3e7c70896ffeeef32b9c950ywan * that can be found in the LICENSE file in the root of the source 6233d2500723e5594f3e7c70896ffeeef32b9c950ywan * tree. An additional intellectual property rights grant can be found 7233d2500723e5594f3e7c70896ffeeef32b9c950ywan * in the file PATENTS. All contributing project authors may 8233d2500723e5594f3e7c70896ffeeef32b9c950ywan * be found in the AUTHORS file in the root of the source tree. 9233d2500723e5594f3e7c70896ffeeef32b9c950ywan */ 10233d2500723e5594f3e7c70896ffeeef32b9c950ywan#include "vp9/decoder/vp9_read_bit_buffer.h" 11233d2500723e5594f3e7c70896ffeeef32b9c950ywan 12233d2500723e5594f3e7c70896ffeeef32b9c950ywansize_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) { 13233d2500723e5594f3e7c70896ffeeef32b9c950ywan return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0); 14233d2500723e5594f3e7c70896ffeeef32b9c950ywan} 15233d2500723e5594f3e7c70896ffeeef32b9c950ywan 16233d2500723e5594f3e7c70896ffeeef32b9c950ywanint vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) { 17233d2500723e5594f3e7c70896ffeeef32b9c950ywan const size_t off = rb->bit_offset; 18233d2500723e5594f3e7c70896ffeeef32b9c950ywan const size_t p = off / CHAR_BIT; 19233d2500723e5594f3e7c70896ffeeef32b9c950ywan const int q = CHAR_BIT - 1 - (int)off % CHAR_BIT; 20233d2500723e5594f3e7c70896ffeeef32b9c950ywan if (rb->bit_buffer + p >= rb->bit_buffer_end) { 21233d2500723e5594f3e7c70896ffeeef32b9c950ywan rb->error_handler(rb->error_handler_data); 22233d2500723e5594f3e7c70896ffeeef32b9c950ywan return 0; 23233d2500723e5594f3e7c70896ffeeef32b9c950ywan } else { 24233d2500723e5594f3e7c70896ffeeef32b9c950ywan const int bit = (rb->bit_buffer[p] & (1 << q)) >> q; 25233d2500723e5594f3e7c70896ffeeef32b9c950ywan rb->bit_offset = off + 1; 26233d2500723e5594f3e7c70896ffeeef32b9c950ywan return bit; 27233d2500723e5594f3e7c70896ffeeef32b9c950ywan } 28233d2500723e5594f3e7c70896ffeeef32b9c950ywan} 29233d2500723e5594f3e7c70896ffeeef32b9c950ywan 30233d2500723e5594f3e7c70896ffeeef32b9c950ywanint vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) { 31233d2500723e5594f3e7c70896ffeeef32b9c950ywan int value = 0, bit; 32233d2500723e5594f3e7c70896ffeeef32b9c950ywan for (bit = bits - 1; bit >= 0; bit--) 33233d2500723e5594f3e7c70896ffeeef32b9c950ywan value |= vp9_rb_read_bit(rb) << bit; 34233d2500723e5594f3e7c70896ffeeef32b9c950ywan return value; 35233d2500723e5594f3e7c70896ffeeef32b9c950ywan} 36233d2500723e5594f3e7c70896ffeeef32b9c950ywan 37233d2500723e5594f3e7c70896ffeeef32b9c950ywanint vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb, 38233d2500723e5594f3e7c70896ffeeef32b9c950ywan int bits) { 39233d2500723e5594f3e7c70896ffeeef32b9c950ywan const int value = vp9_rb_read_literal(rb, bits); 40233d2500723e5594f3e7c70896ffeeef32b9c950ywan return vp9_rb_read_bit(rb) ? -value : value; 41233d2500723e5594f3e7c70896ffeeef32b9c950ywan} 42