gecko/modules/brotli/dec/bit_reader.c

49 lines
1.2 KiB
C

/* Copyright 2013 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
/* Bit reading helpers */
#include "./bit_reader.h"
#include "./port.h"
#include "./types.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
void BrotliInitBitReader(BrotliBitReader* const br) {
br->val_ = 0;
br->bit_pos_ = sizeof(br->val_) << 3;
}
int BrotliWarmupBitReader(BrotliBitReader* const br) {
size_t aligned_read_mask = (sizeof(br->val_) >> 1) - 1;
/* Fixing alignment after unaligned BrotliFillWindow would result accumulator
overflow. If unalignment is caused by BrotliSafeReadBits, then there is
enough space in accumulator to fix aligment. */
if (!BROTLI_ALIGNED_READ) {
aligned_read_mask = 0;
}
if (BrotliGetAvailableBits(br) == 0) {
if (!BrotliPullByte(br)) {
return 0;
}
}
while ((((size_t)br->next_in) & aligned_read_mask) != 0) {
if (!BrotliPullByte(br)) {
/* If we consumed all the input, we don't care about the alignment. */
return 1;
}
}
return 1;
}
#if defined(__cplusplus) || defined(c_plusplus)
} /* extern "C" */
#endif