Use C-style comments in the brotli decoder.
This commit is contained in:
Zoltan Szabadka
+49
-47
@@ -1,18 +1,19 @@
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// Copyright 2013 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Bit reading helpers
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/* Copyright 2013 Google Inc. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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Bit reading helpers
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*/
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#ifndef BROTLI_DEC_BIT_READER_H_
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#define BROTLI_DEC_BIT_READER_H_
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@@ -38,26 +39,26 @@ static const uint32_t kBitMask[BROTLI_MAX_NUM_BIT_READ] = {
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};
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typedef struct {
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// Input byte buffer, consist of a ringbuffer and a "slack" region where
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// bytes from the start of the ringbuffer are copied.
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/* Input byte buffer, consist of a ringbuffer and a "slack" region where */
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/* bytes from the start of the ringbuffer are copied. */
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uint8_t buf_[BROTLI_IBUF_SIZE];
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BrotliInput input_; // input callback
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uint64_t val_; // pre-fetched bits
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size_t pos_; // byte position in stream
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int bit_pos_; // current bit-reading position in val_
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size_t end_pos_; // current end position in stream
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int eos_; // input stream is finished
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BrotliInput input_; /* input callback */
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uint64_t val_; /* pre-fetched bits */
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size_t pos_; /* byte position in stream */
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int bit_pos_; /* current bit-reading position in val_ */
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size_t end_pos_; /* current end position in stream */
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int eos_; /* input stream is finished */
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} BrotliBitReader;
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int BrotliInitBitReader(BrotliBitReader* const br, BrotliInput input);
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// Return the prefetched bits, so they can be looked up.
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/* Return the prefetched bits, so they can be looked up. */
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static BROTLI_INLINE uint32_t BrotliPrefetchBits(BrotliBitReader* const br) {
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return (uint32_t)(br->val_ >> br->bit_pos_);
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}
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// For jumping over a number of bits in the bit stream when accessed with
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// BrotliPrefetchBits and BrotliFillBitWindow.
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/* For jumping over a number of bits in the bit stream when accessed with */
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/* BrotliPrefetchBits and BrotliFillBitWindow. */
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static BROTLI_INLINE void BrotliSetBitPos(BrotliBitReader* const br, int val) {
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#ifdef BROTLI_DECODE_DEBUG
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int n_bits = val - br->bit_pos_;
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@@ -68,7 +69,7 @@ static BROTLI_INLINE void BrotliSetBitPos(BrotliBitReader* const br, int val) {
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br->bit_pos_ = val;
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}
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// Reload up to 64 bits byte-by-byte
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/* Reload up to 64 bits byte-by-byte */
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static BROTLI_INLINE void ShiftBytes(BrotliBitReader* const br) {
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while (br->bit_pos_ >= 8) {
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br->val_ >>= 8;
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@@ -78,17 +79,18 @@ static BROTLI_INLINE void ShiftBytes(BrotliBitReader* const br) {
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}
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}
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// Fills up the input ringbuffer by calling the input callback.
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//
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// Does nothing if there are at least 32 bytes present after current position.
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//
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// Returns 0 if either:
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// - the input callback returned an error, or
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// - there is no more input and the position is past the end of the stream.
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//
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// After encountering the end of the input stream, 32 additional zero bytes are
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// copied to the ringbuffer, therefore it is safe to call this function after
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// every 32 bytes of input is read.
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/* Fills up the input ringbuffer by calling the input callback.
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Does nothing if there are at least 32 bytes present after current position.
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Returns 0 if either:
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- the input callback returned an error, or
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- there is no more input and the position is past the end of the stream.
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After encountering the end of the input stream, 32 additional zero bytes are
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copied to the ringbuffer, therefore it is safe to call this function after
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every 32 bytes of input is read.
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*/
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static BROTLI_INLINE int BrotliReadMoreInput(BrotliBitReader* const br) {
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if (br->pos_ + 32 < br->end_pos_) {
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return 1;
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@@ -102,7 +104,7 @@ static BROTLI_INLINE int BrotliReadMoreInput(BrotliBitReader* const br) {
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}
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if (bytes_read < BROTLI_READ_SIZE) {
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br->eos_ = 1;
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// Store 32 bytes of zero after the stream end.
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/* Store 32 bytes of zero after the stream end. */
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#if (defined(__x86_64__) || defined(_M_X64))
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*(uint64_t*)(dst + bytes_read) = 0;
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*(uint64_t*)(dst + bytes_read + 8) = 0;
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@@ -113,7 +115,7 @@ static BROTLI_INLINE int BrotliReadMoreInput(BrotliBitReader* const br) {
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#endif
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}
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if (dst == br->buf_) {
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// Copy the head of the ringbuffer to the slack region.
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/* Copy the head of the ringbuffer to the slack region. */
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#if (defined(__x86_64__) || defined(_M_X64))
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UNALIGNED_COPY64(br->buf_ + BROTLI_IBUF_SIZE - 32, br->buf_);
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UNALIGNED_COPY64(br->buf_ + BROTLI_IBUF_SIZE - 24, br->buf_ + 8);
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@@ -128,14 +130,14 @@ static BROTLI_INLINE int BrotliReadMoreInput(BrotliBitReader* const br) {
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}
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}
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// Advances the Read buffer by 5 bytes to make room for reading next 24 bits.
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/* Advances the Read buffer by 5 bytes to make room for reading next 24 bits. */
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static BROTLI_INLINE void BrotliFillBitWindow(BrotliBitReader* const br) {
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if (br->bit_pos_ >= 40) {
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#if (defined(__x86_64__) || defined(_M_X64))
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br->val_ >>= 40;
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br->bit_pos_ -= 40;
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// The expression below needs a little-endian arch to work correctly.
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// This gives a large speedup for decoding speed.
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/* The expression below needs a little-endian arch to work correctly. */
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/* This gives a large speedup for decoding speed. */
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br->val_ |= *(const uint64_t*)(
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br->buf_ + (br->pos_ & BROTLI_IBUF_MASK)) << 24;
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br->pos_ += 5;
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@@ -145,8 +147,8 @@ static BROTLI_INLINE void BrotliFillBitWindow(BrotliBitReader* const br) {
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}
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}
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// Reads the specified number of bits from Read Buffer.
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// Requires that n_bits is positive.
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/* Reads the specified number of bits from Read Buffer. */
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/* Requires that n_bits is positive. */
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static BROTLI_INLINE uint32_t BrotliReadBits(
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BrotliBitReader* const br, int n_bits) {
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uint32_t val;
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@@ -161,7 +163,7 @@ static BROTLI_INLINE uint32_t BrotliReadBits(
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}
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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} /* extern "C" */
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#endif
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#endif // BROTLI_DEC_BIT_READER_H_
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#endif /* BROTLI_DEC_BIT_READER_H_ */
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