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             : 
      12             : #include <limits.h>
      13             : #include <stdlib.h>
      14             : 
      15             : #include "./aom_config.h"
      16             : #include "./bitwriter_buffer.h"
      17             : 
      18           0 : uint32_t aom_wb_bytes_written(const struct aom_write_bit_buffer *wb) {
      19           0 :   return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
      20             : }
      21             : 
      22           0 : void aom_wb_write_bit(struct aom_write_bit_buffer *wb, int bit) {
      23           0 :   const int off = (int)wb->bit_offset;
      24           0 :   const int p = off / CHAR_BIT;
      25           0 :   const int q = CHAR_BIT - 1 - off % CHAR_BIT;
      26           0 :   if (q == CHAR_BIT - 1) {
      27             :     // Zero next char and write bit
      28           0 :     wb->bit_buffer[p] = bit << q;
      29             :   } else {
      30           0 :     wb->bit_buffer[p] &= ~(1 << q);
      31           0 :     wb->bit_buffer[p] |= bit << q;
      32             :   }
      33           0 :   wb->bit_offset = off + 1;
      34           0 : }
      35             : 
      36           0 : void aom_wb_overwrite_bit(struct aom_write_bit_buffer *wb, int bit) {
      37             :   // Do not zero bytes but overwrite exisiting values
      38           0 :   const int off = (int)wb->bit_offset;
      39           0 :   const int p = off / CHAR_BIT;
      40           0 :   const int q = CHAR_BIT - 1 - off % CHAR_BIT;
      41           0 :   wb->bit_buffer[p] &= ~(1 << q);
      42           0 :   wb->bit_buffer[p] |= bit << q;
      43           0 :   wb->bit_offset = off + 1;
      44           0 : }
      45             : 
      46           0 : void aom_wb_write_literal(struct aom_write_bit_buffer *wb, int data, int bits) {
      47             :   int bit;
      48           0 :   for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
      49           0 : }
      50             : 
      51           0 : void aom_wb_overwrite_literal(struct aom_write_bit_buffer *wb, int data,
      52             :                               int bits) {
      53             :   int bit;
      54           0 :   for (bit = bits - 1; bit >= 0; bit--)
      55           0 :     aom_wb_overwrite_bit(wb, (data >> bit) & 1);
      56           0 : }
      57             : 
      58           0 : void aom_wb_write_inv_signed_literal(struct aom_write_bit_buffer *wb, int data,
      59             :                                      int bits) {
      60           0 :   aom_wb_write_literal(wb, data, bits + 1);
      61           0 : }