Line data    Source code

       1             : /*
       2             :  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
       3             :  *
       4             :  * This source code is subject to the terms of the BSD 2 Clause License and
       5             :  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
       6             :  * was not distributed with this source code in the LICENSE file, you can
       7             :  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
       8             :  * Media Patent License 1.0 was not distributed with this source code in the
       9             :  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
      10             :  */
      11             : #include "./aom_config.h"
      12             : #include "./bitreader_buffer.h"
      13             : 
      14           0 : size_t aom_rb_bytes_read(struct aom_read_bit_buffer *rb) {
      15           0 :   return (rb->bit_offset + 7) >> 3;
      16             : }
      17             : 
      18           0 : int aom_rb_read_bit(struct aom_read_bit_buffer *rb) {
      19           0 :   const uint32_t off = rb->bit_offset;
      20           0 :   const uint32_t p = off >> 3;
      21           0 :   const int q = 7 - (int)(off & 0x7);
      22           0 :   if (rb->bit_buffer + p < rb->bit_buffer_end) {
      23           0 :     const int bit = (rb->bit_buffer[p] >> q) & 1;
      24           0 :     rb->bit_offset = off + 1;
      25           0 :     return bit;
      26             :   } else {
      27           0 :     if (rb->error_handler) rb->error_handler(rb->error_handler_data);
      28           0 :     return 0;
      29             :   }
      30             : }
      31             : 
      32           0 : int aom_rb_read_literal(struct aom_read_bit_buffer *rb, int bits) {
      33           0 :   int value = 0, bit;
      34           0 :   for (bit = bits - 1; bit >= 0; bit--) value |= aom_rb_read_bit(rb) << bit;
      35           0 :   return value;
      36             : }
      37             : 
      38           0 : int aom_rb_read_signed_literal(struct aom_read_bit_buffer *rb, int bits) {
      39           0 :   const int value = aom_rb_read_literal(rb, bits);
      40           0 :   return aom_rb_read_bit(rb) ? -value : value;
      41             : }
      42             : 
      43           0 : int aom_rb_read_inv_signed_literal(struct aom_read_bit_buffer *rb, int bits) {
      44           0 :   const int nbits = sizeof(unsigned) * 8 - bits - 1;
      45           0 :   const unsigned value = (unsigned)aom_rb_read_literal(rb, bits + 1) << nbits;
      46           0 :   return ((int)value) >> nbits;
      47             : }