Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : #include "./vpx_config.h"
      11             : #include "./bitreader_buffer.h"
      12             : 
      13           0 : size_t vpx_rb_bytes_read(struct vpx_read_bit_buffer *rb) {
      14           0 :   return (rb->bit_offset + 7) >> 3;
      15             : }
      16             : 
      17           0 : int vpx_rb_read_bit(struct vpx_read_bit_buffer *rb) {
      18           0 :   const size_t off = rb->bit_offset;
      19           0 :   const size_t p = off >> 3;
      20           0 :   const int q = 7 - (int)(off & 0x7);
      21           0 :   if (rb->bit_buffer + p < rb->bit_buffer_end) {
      22           0 :     const int bit = (rb->bit_buffer[p] >> q) & 1;
      23           0 :     rb->bit_offset = off + 1;
      24           0 :     return bit;
      25             :   } else {
      26           0 :     rb->error_handler(rb->error_handler_data);
      27           0 :     return 0;
      28             :   }
      29             : }
      30             : 
      31           0 : int vpx_rb_read_literal(struct vpx_read_bit_buffer *rb, int bits) {
      32           0 :   int value = 0, bit;
      33           0 :   for (bit = bits - 1; bit >= 0; bit--) value |= vpx_rb_read_bit(rb) << bit;
      34           0 :   return value;
      35             : }
      36             : 
      37           0 : int vpx_rb_read_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {
      38           0 :   const int value = vpx_rb_read_literal(rb, bits);
      39           0 :   return vpx_rb_read_bit(rb) ? -value : value;
      40             : }
      41             : 
      42           0 : int vpx_rb_read_inv_signed_literal(struct vpx_read_bit_buffer *rb, int bits) {
      43             : #if CONFIG_MISC_FIXES
      44             :   const int nbits = sizeof(unsigned) * 8 - bits - 1;
      45             :   const unsigned value = (unsigned)vpx_rb_read_literal(rb, bits + 1) << nbits;
      46             :   return ((int)value) >> nbits;
      47             : #else
      48           0 :   return vpx_rb_read_signed_literal(rb, bits);
      49             : #endif
      50             : }