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0.5-2.9% decoder speedup

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PiperOrigin-RevId: 529412095
This commit is contained in:
Evgenii Kliuchnikov 2023-05-04 15:09:05 +00:00 committed by Evgenii Kliuchnikov
parent 11abde4c96
commit e252f1fc15
2 changed files with 48 additions and 40 deletions
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3
c/dec/bit_reader.c
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@ -29,7 +29,7 @@ const brotli_reg_t kBrotliBitMask[33] = { 0x00000000,
void BrotliInitBitReader(BrotliBitReader* const br) { void BrotliInitBitReader(BrotliBitReader* const br) {
br->val_ = 0; br->val_ = 0;
br->bit_pos_ = sizeof(br->val_) << 3; br->bit_pos_ = 0;
} }
BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br) { BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br) {
@ -41,6 +41,7 @@ BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br) {
aligned_read_mask = 0; aligned_read_mask = 0;
} }
if (BrotliGetAvailableBits(br) == 0) { if (BrotliGetAvailableBits(br) == 0) {
br->val_ = 0;
if (!BrotliPullByte(br)) { if (!BrotliPullByte(br)) {
return BROTLI_FALSE; return BROTLI_FALSE;
} }

85
c/dec/bit_reader.h
View File

@ -102,7 +102,7 @@ static BROTLI_INLINE void BrotliBitReaderRestoreState(
static BROTLI_INLINE brotli_reg_t BrotliGetAvailableBits( static BROTLI_INLINE brotli_reg_t BrotliGetAvailableBits(
const BrotliBitReader* br) { const BrotliBitReader* br) {
return (BROTLI_64_BITS ? 64 : 32) - br->bit_pos_; return br->bit_pos_;
} }
/* Returns amount of unread bytes the bit reader still has buffered from the /* Returns amount of unread bytes the bit reader still has buffered from the
@ -122,6 +122,17 @@ static BROTLI_INLINE BROTLI_BOOL BrotliCheckInputAmount(
return TO_BROTLI_BOOL(br->next_in < br->guard_in); return TO_BROTLI_BOOL(br->next_in < br->guard_in);
} }
/* Load more bits into accumulator. */
static BROTLI_INLINE brotli_reg_t BrotliBitReaderLoadBits(brotli_reg_t val,
brotli_reg_t new_bits,
brotli_reg_t count,
brotli_reg_t offset) {
BROTLI_DCHECK(
!((val >> offset) & ~new_bits & ~(~((brotli_reg_t)0) << count)));
(void)count;
return val | (new_bits << offset);
}
/* Guarantees that there are at least |n_bits| + 1 bits in accumulator. /* Guarantees that there are at least |n_bits| + 1 bits in accumulator.
Precondition: accumulator contains at least 1 bit. Precondition: accumulator contains at least 1 bit.
|n_bits| should be in the range [1..24] for regular build. For portable |n_bits| should be in the range [1..24] for regular build. For portable
@ -132,30 +143,27 @@ static BROTLI_INLINE void BrotliFillBitWindow(
if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) && if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) &&
(n_bits <= 8)) { (n_bits <= 8)) {
brotli_reg_t bit_pos = br->bit_pos_; brotli_reg_t bit_pos = br->bit_pos_;
if (bit_pos >= 56) { if (bit_pos <= 8) {
br->val_ = br->val_ = BrotliBitReaderLoadBits(br->val_,
(br->val_ >> 56) | (BROTLI_UNALIGNED_LOAD64LE(br->next_in) << 8); BROTLI_UNALIGNED_LOAD64LE(br->next_in), 56, bit_pos);
br->bit_pos_ = br->bit_pos_ = bit_pos + 56;
bit_pos ^ 56; /* here same as -= 56 because of the if condition */
br->next_in += 7; br->next_in += 7;
} }
} else if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) && } else if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) &&
(n_bits <= 16)) { (n_bits <= 16)) {
brotli_reg_t bit_pos = br->bit_pos_; brotli_reg_t bit_pos = br->bit_pos_;
if (bit_pos >= 48) { if (bit_pos <= 16) {
br->val_ = br->val_ = BrotliBitReaderLoadBits(br->val_,
(br->val_ >> 48) | (BROTLI_UNALIGNED_LOAD64LE(br->next_in) << 16); BROTLI_UNALIGNED_LOAD64LE(br->next_in), 48, bit_pos);
br->bit_pos_ = br->bit_pos_ = bit_pos + 48;
bit_pos ^ 48; /* here same as -= 48 because of the if condition */
br->next_in += 6; br->next_in += 6;
} }
} else { } else {
brotli_reg_t bit_pos = br->bit_pos_; brotli_reg_t bit_pos = br->bit_pos_;
if (bit_pos >= 32) { if (bit_pos <= 32) {
br->val_ = (br->val_ >> 32) | br->val_ = BrotliBitReaderLoadBits(br->val_,
(((uint64_t)BROTLI_UNALIGNED_LOAD32LE(br->next_in)) << 32); (uint64_t)BROTLI_UNALIGNED_LOAD32LE(br->next_in), 32, bit_pos);
br->bit_pos_ = br->bit_pos_ = bit_pos + 32;
bit_pos ^ 32; /* here same as -= 32 because of the if condition */
br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ; br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ;
} }
} }
@ -163,20 +171,18 @@ static BROTLI_INLINE void BrotliFillBitWindow(
if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) && if (BROTLI_UNALIGNED_READ_FAST && BROTLI_IS_CONSTANT(n_bits) &&
(n_bits <= 8)) { (n_bits <= 8)) {
brotli_reg_t bit_pos = br->bit_pos_; brotli_reg_t bit_pos = br->bit_pos_;
if (bit_pos >= 24) { if (bit_pos <= 8) {
br->val_ = br->val_ = BrotliBitReaderLoadBits(br->val_,
(br->val_ >> 24) | (BROTLI_UNALIGNED_LOAD32LE(br->next_in) << 8); BROTLI_UNALIGNED_LOAD32LE(br->next_in), 24, bit_pos);
br->bit_pos_ = br->bit_pos_ = bit_pos + 24;
bit_pos ^ 24; /* here same as -= 24 because of the if condition */
br->next_in += 3; br->next_in += 3;
} }
} else { } else {
brotli_reg_t bit_pos = br->bit_pos_; brotli_reg_t bit_pos = br->bit_pos_;
if (bit_pos >= 16) { if (bit_pos <= 16) {
br->val_ = (br->val_ >> 16) | br->val_ = BrotliBitReaderLoadBits(br->val_,
(((brotli_reg_t)BROTLI_UNALIGNED_LOAD16LE(br->next_in)) << 16); (uint32_t)BROTLI_UNALIGNED_LOAD16LE(br->next_in), 16, bit_pos);
br->bit_pos_ = br->bit_pos_ = bit_pos + 16;
bit_pos ^ 16; /* here same as -= 16 because of the if condition */
br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ; br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ;
} }
} }
@ -195,13 +201,9 @@ static BROTLI_INLINE BROTLI_BOOL BrotliPullByte(BrotliBitReader* const br) {
if (br->next_in == br->last_in) { if (br->next_in == br->last_in) {
return BROTLI_FALSE; return BROTLI_FALSE;
} }
br->val_ >>= 8; br->val_ = BrotliBitReaderLoadBits(br->val_,
#if (BROTLI_64_BITS) (brotli_reg_t)*br->next_in, 8, br->bit_pos_);
br->val_ |= ((uint64_t)*br->next_in) << 56; br->bit_pos_ += 8;
#else
br->val_ |= ((brotli_reg_t)*br->next_in) << 24;
#endif
br->bit_pos_ -= 8;
++br->next_in; ++br->next_in;
return BROTLI_TRUE; return BROTLI_TRUE;
} }
@ -210,7 +212,7 @@ static BROTLI_INLINE BROTLI_BOOL BrotliPullByte(BrotliBitReader* const br) {
The number of valid bits could be calculated by BrotliGetAvailableBits. */ The number of valid bits could be calculated by BrotliGetAvailableBits. */
static BROTLI_INLINE brotli_reg_t BrotliGetBitsUnmasked( static BROTLI_INLINE brotli_reg_t BrotliGetBitsUnmasked(
BrotliBitReader* const br) { BrotliBitReader* const br) {
return br->val_ >> br->bit_pos_; return br->val_;
} }
/* Like BrotliGetBits, but does not mask the result. /* Like BrotliGetBits, but does not mask the result.
@ -245,7 +247,8 @@ static BROTLI_INLINE BROTLI_BOOL BrotliSafeGetBits(
/* Advances the bit pos by |n_bits|. */ /* Advances the bit pos by |n_bits|. */
static BROTLI_INLINE void BrotliDropBits( static BROTLI_INLINE void BrotliDropBits(
BrotliBitReader* const br, brotli_reg_t n_bits) { BrotliBitReader* const br, brotli_reg_t n_bits) {
br->bit_pos_ += n_bits; br->bit_pos_ -= n_bits;
br->val_ >>= n_bits;
} }
static BROTLI_INLINE void BrotliBitReaderUnload(BrotliBitReader* br) { static BROTLI_INLINE void BrotliBitReaderUnload(BrotliBitReader* br) {
@ -253,12 +256,11 @@ static BROTLI_INLINE void BrotliBitReaderUnload(BrotliBitReader* br) {
brotli_reg_t unused_bits = unused_bytes << 3; brotli_reg_t unused_bits = unused_bytes << 3;
br->next_in = br->next_in =
(unused_bytes == 0) ? br->next_in : (br->next_in - unused_bytes); (unused_bytes == 0) ? br->next_in : (br->next_in - unused_bytes);
if (unused_bits == sizeof(br->val_) << 3) { br->bit_pos_ -= unused_bits;
/* Prepare for possible input discontinuity. */
if (br->bit_pos_ == 0) {
br->val_ = 0; br->val_ = 0;
} else {
br->val_ <<= unused_bits;
} }
br->bit_pos_ += unused_bits;
} }
/* Reads the specified number of bits from |br| and advances the bit pos. /* Reads the specified number of bits from |br| and advances the bit pos.
@ -373,6 +375,10 @@ static BROTLI_INLINE void BrotliCopyBytes(uint8_t* dest,
++dest; ++dest;
--num; --num;
} }
/* Prepare for possible input discontinuity. */
if (br->bit_pos_ == 0) {
br->val_ = 0;
}
if (num > 0) { if (num > 0) {
memcpy(dest, br->next_in, num); memcpy(dest, br->next_in, num);
BrotliDropBytes(br, num); BrotliDropBytes(br, num);
@ -383,6 +389,7 @@ BROTLI_UNUSED_FUNCTION void BrotliBitReaderSuppressUnusedFunctions(void) {
BROTLI_UNUSED(&BrotliBitReaderSuppressUnusedFunctions); BROTLI_UNUSED(&BrotliBitReaderSuppressUnusedFunctions);
BROTLI_UNUSED(&BrotliBitReaderGetAvailIn); BROTLI_UNUSED(&BrotliBitReaderGetAvailIn);
BROTLI_UNUSED(&BrotliBitReaderLoadBits);
BROTLI_UNUSED(&BrotliBitReaderRestoreState); BROTLI_UNUSED(&BrotliBitReaderRestoreState);
BROTLI_UNUSED(&BrotliBitReaderSaveState); BROTLI_UNUSED(&BrotliBitReaderSaveState);
BROTLI_UNUSED(&BrotliBitReaderSetInput); BROTLI_UNUSED(&BrotliBitReaderSetInput);