Line data    Source code

       1             : /* Copyright 2013 Google Inc. All Rights Reserved.
       2             : 
       3             :    Distributed under MIT license.
       4             :    See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
       5             : */
       6             : 
       7             : /* Bit reading helpers */
       8             : 
       9             : #include "./bit_reader.h"
      10             : 
      11             : #include "./port.h"
      12             : #include "./types.h"
      13             : 
      14             : #if defined(__cplusplus) || defined(c_plusplus)
      15             : extern "C" {
      16             : #endif
      17             : 
      18           0 : void BrotliInitBitReader(BrotliBitReader* const br) {
      19           0 :   br->val_ = 0;
      20           0 :   br->bit_pos_ = sizeof(br->val_) << 3;
      21           0 : }
      22             : 
      23           0 : int BrotliWarmupBitReader(BrotliBitReader* const br) {
      24           0 :   size_t aligned_read_mask = (sizeof(br->val_) >> 1) - 1;
      25             :   /* Fixing alignment after unaligned BrotliFillWindow would result accumulator
      26             :      overflow. If unalignment is caused by BrotliSafeReadBits, then there is
      27             :      enough space in accumulator to fix aligment. */
      28             :   if (!BROTLI_ALIGNED_READ) {
      29             :     aligned_read_mask = 0;
      30             :   }
      31           0 :   if (BrotliGetAvailableBits(br) == 0) {
      32           0 :     if (!BrotliPullByte(br)) {
      33           0 :       return 0;
      34             :     }
      35             :   }
      36             : 
      37           0 :   while ((((size_t)br->next_in) & aligned_read_mask) != 0) {
      38           0 :     if (!BrotliPullByte(br)) {
      39             :       /* If we consumed all the input, we don't care about the alignment. */
      40           0 :       return 1;
      41             :     }
      42             :   }
      43           0 :   return 1;
      44             : }
      45             : 
      46             : #if defined(__cplusplus) || defined(c_plusplus)
      47             : }  /* extern "C" */
      48             : #endif