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Unified Diff: third_party/brotli/enc/compress_fragment_two_pass.c

Issue 2537133002: Update brotli to v1.0.0-snapshot. (Closed)
Patch Set: Fixed typo Created 4 years ago
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Index: third_party/brotli/enc/compress_fragment_two_pass.c
diff --git a/third_party/brotli/enc/compress_fragment_two_pass.cc b/third_party/brotli/enc/compress_fragment_two_pass.c
similarity index 33%
rename from third_party/brotli/enc/compress_fragment_two_pass.cc
rename to third_party/brotli/enc/compress_fragment_two_pass.c
index a032740d655a628dac0d81bc8a8ab2eb9bf18108..1768dd711b11d227d1ab3fb9fa8646c99b70a2e1 100644
--- a/third_party/brotli/enc/compress_fragment_two_pass.cc
+++ b/third_party/brotli/enc/compress_fragment_two_pass.c
@@ -4,118 +4,132 @@
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
-// Function for fast encoding of an input fragment, independently from the input
-// history. This function uses two-pass processing: in the first pass we save
-// the found backward matches and literal bytes into a buffer, and in the
-// second pass we emit them into the bit stream using prefix codes built based
-// on the actual command and literal byte histograms.
+/* Function for fast encoding of an input fragment, independently from the input
+ history. This function uses two-pass processing: in the first pass we save
+ the found backward matches and literal bytes into a buffer, and in the
+ second pass we emit them into the bit stream using prefix codes built based
+ on the actual command and literal byte histograms. */
#include "./compress_fragment_two_pass.h"
-#include <algorithm>
+#include <string.h> /* memcmp, memcpy, memset */
-#include "./brotli_bit_stream.h"
+#include "../common/constants.h"
+#include <brotli/types.h>
#include "./bit_cost.h"
+#include "./brotli_bit_stream.h"
#include "./entropy_encode.h"
#include "./fast_log.h"
#include "./find_match_length.h"
+#include "./memory.h"
#include "./port.h"
-#include "./types.h"
#include "./write_bits.h"
-namespace brotli {
-// kHashMul32 multiplier has these properties:
-// * The multiplier must be odd. Otherwise we may lose the highest bit.
-// * No long streaks of 1s or 0s.
-// * There is no effort to ensure that it is a prime, the oddity is enough
-// for this use.
-// * The number has been tuned heuristically against compression benchmarks.
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+/* Same as MaxBackwardLimit(18) */
+#define MAX_DISTANCE ((1 << 18) - BROTLI_WINDOW_GAP)
+
+/* kHashMul32 multiplier has these properties:
+ * The multiplier must be odd. Otherwise we may lose the highest bit.
+ * No long streaks of ones or zeros.
+ * There is no effort to ensure that it is a prime, the oddity is enough
+ for this use.
+ * The number has been tuned heuristically against compression benchmarks. */
static const uint32_t kHashMul32 = 0x1e35a7bd;
-static inline uint32_t Hash(const uint8_t* p, size_t shift) {
+static BROTLI_INLINE uint32_t Hash(const uint8_t* p, size_t shift) {
const uint64_t h = (BROTLI_UNALIGNED_LOAD64(p) << 16) * kHashMul32;
- return static_cast<uint32_t>(h >> shift);
+ return (uint32_t)(h >> shift);
}
-static inline uint32_t HashBytesAtOffset(uint64_t v, int offset, size_t shift) {
+static BROTLI_INLINE uint32_t HashBytesAtOffset(
+ uint64_t v, int offset, size_t shift) {
assert(offset >= 0);
assert(offset <= 2);
- const uint64_t h = ((v >> (8 * offset)) << 16) * kHashMul32;
- return static_cast<uint32_t>(h >> shift);
+ {
+ const uint64_t h = ((v >> (8 * offset)) << 16) * kHashMul32;
+ return (uint32_t)(h >> shift);
+ }
}
-static inline int IsMatch(const uint8_t* p1, const uint8_t* p2) {
- return (BROTLI_UNALIGNED_LOAD32(p1) == BROTLI_UNALIGNED_LOAD32(p2) &&
- p1[4] == p2[4] &&
- p1[5] == p2[5]);
+static BROTLI_INLINE BROTLI_BOOL IsMatch(const uint8_t* p1, const uint8_t* p2) {
+ return TO_BROTLI_BOOL(
+ BROTLI_UNALIGNED_LOAD32(p1) == BROTLI_UNALIGNED_LOAD32(p2) &&
+ p1[4] == p2[4] &&
+ p1[5] == p2[5]);
}
-// Builds a command and distance prefix code (each 64 symbols) into "depth" and
-// "bits" based on "histogram" and stores it into the bit stream.
+/* Builds a command and distance prefix code (each 64 symbols) into "depth" and
+ "bits" based on "histogram" and stores it into the bit stream. */
static void BuildAndStoreCommandPrefixCode(
const uint32_t histogram[128],
uint8_t depth[128], uint16_t bits[128],
size_t* storage_ix, uint8_t* storage) {
- // Tree size for building a tree over 64 symbols is 2 * 64 + 1.
- static const size_t kTreeSize = 129;
- HuffmanTree tree[kTreeSize];
- CreateHuffmanTree(histogram, 64, 15, tree, depth);
- CreateHuffmanTree(&histogram[64], 64, 14, tree, &depth[64]);
- // We have to jump through a few hoopes here in order to compute
- // the command bits because the symbols are in a different order than in
- // the full alphabet. This looks complicated, but having the symbols
- // in this order in the command bits saves a few branches in the Emit*
- // functions.
- uint8_t cmd_depth[64];
+ /* Tree size for building a tree over 64 symbols is 2 * 64 + 1. */
+ HuffmanTree tree[129];
+ uint8_t cmd_depth[BROTLI_NUM_COMMAND_SYMBOLS] = { 0 };
uint16_t cmd_bits[64];
+ BrotliCreateHuffmanTree(histogram, 64, 15, tree, depth);
+ BrotliCreateHuffmanTree(&histogram[64], 64, 14, tree, &depth[64]);
+ /* We have to jump through a few hoops here in order to compute
+ the command bits because the symbols are in a different order than in
+ the full alphabet. This looks complicated, but having the symbols
+ in this order in the command bits saves a few branches in the Emit*
+ functions. */
memcpy(cmd_depth, depth + 24, 24);
memcpy(cmd_depth + 24, depth, 8);
memcpy(cmd_depth + 32, depth + 48, 8);
memcpy(cmd_depth + 40, depth + 8, 8);
memcpy(cmd_depth + 48, depth + 56, 8);
memcpy(cmd_depth + 56, depth + 16, 8);
- ConvertBitDepthsToSymbols(cmd_depth, 64, cmd_bits);
+ BrotliConvertBitDepthsToSymbols(cmd_depth, 64, cmd_bits);
memcpy(bits, cmd_bits + 24, 16);
memcpy(bits + 8, cmd_bits + 40, 16);
memcpy(bits + 16, cmd_bits + 56, 16);
memcpy(bits + 24, cmd_bits, 48);
memcpy(bits + 48, cmd_bits + 32, 16);
memcpy(bits + 56, cmd_bits + 48, 16);
- ConvertBitDepthsToSymbols(&depth[64], 64, &bits[64]);
+ BrotliConvertBitDepthsToSymbols(&depth[64], 64, &bits[64]);
{
- // Create the bit length array for the full command alphabet.
- uint8_t cmd_depth[704] = { 0 };
+ /* Create the bit length array for the full command alphabet. */
+ size_t i;
+ memset(cmd_depth, 0, 64); /* only 64 first values were used */
memcpy(cmd_depth, depth + 24, 8);
memcpy(cmd_depth + 64, depth + 32, 8);
memcpy(cmd_depth + 128, depth + 40, 8);
memcpy(cmd_depth + 192, depth + 48, 8);
memcpy(cmd_depth + 384, depth + 56, 8);
- for (size_t i = 0; i < 8; ++i) {
+ for (i = 0; i < 8; ++i) {
cmd_depth[128 + 8 * i] = depth[i];
cmd_depth[256 + 8 * i] = depth[8 + i];
cmd_depth[448 + 8 * i] = depth[16 + i];
}
- StoreHuffmanTree(cmd_depth, 704, tree, storage_ix, storage);
+ BrotliStoreHuffmanTree(
+ cmd_depth, BROTLI_NUM_COMMAND_SYMBOLS, tree, storage_ix, storage);
}
- StoreHuffmanTree(&depth[64], 64, tree, storage_ix, storage);
+ BrotliStoreHuffmanTree(&depth[64], 64, tree, storage_ix, storage);
}
-inline void EmitInsertLen(uint32_t insertlen, uint32_t** commands) {
+static BROTLI_INLINE void EmitInsertLen(
+ uint32_t insertlen, uint32_t** commands) {
if (insertlen < 6) {
**commands = insertlen;
} else if (insertlen < 130) {
- insertlen -= 2;
- const uint32_t nbits = Log2FloorNonZero(insertlen) - 1u;
- const uint32_t prefix = insertlen >> nbits;
+ const uint32_t tail = insertlen - 2;
+ const uint32_t nbits = Log2FloorNonZero(tail) - 1u;
+ const uint32_t prefix = tail >> nbits;
const uint32_t inscode = (nbits << 1) + prefix + 2;
- const uint32_t extra = insertlen - (prefix << nbits);
+ const uint32_t extra = tail - (prefix << nbits);
**commands = inscode | (extra << 8);
} else if (insertlen < 2114) {
- insertlen -= 66;
- const uint32_t nbits = Log2FloorNonZero(insertlen);
+ const uint32_t tail = insertlen - 66;
+ const uint32_t nbits = Log2FloorNonZero(tail);
const uint32_t code = nbits + 10;
- const uint32_t extra = insertlen - (1 << nbits);
+ const uint32_t extra = tail - (1u << nbits);
**commands = code | (extra << 8);
} else if (insertlen < 6210) {
const uint32_t extra = insertlen - 2114;
@@ -130,161 +144,161 @@ inline void EmitInsertLen(uint32_t insertlen, uint32_t** commands) {
++(*commands);
}
-inline void EmitCopyLen(size_t copylen, uint32_t** commands) {
+static BROTLI_INLINE void EmitCopyLen(size_t copylen, uint32_t** commands) {
if (copylen < 10) {
- **commands = static_cast<uint32_t>(copylen + 38);
+ **commands = (uint32_t)(copylen + 38);
} else if (copylen < 134) {
- copylen -= 6;
- const size_t nbits = Log2FloorNonZero(copylen) - 1;
- const size_t prefix = copylen >> nbits;
+ const size_t tail = copylen - 6;
+ const size_t nbits = Log2FloorNonZero(tail) - 1;
+ const size_t prefix = tail >> nbits;
const size_t code = (nbits << 1) + prefix + 44;
- const size_t extra = copylen - (prefix << nbits);
- **commands = static_cast<uint32_t>(code | (extra << 8));
+ const size_t extra = tail - (prefix << nbits);
+ **commands = (uint32_t)(code | (extra << 8));
} else if (copylen < 2118) {
- copylen -= 70;
- const size_t nbits = Log2FloorNonZero(copylen);
+ const size_t tail = copylen - 70;
+ const size_t nbits = Log2FloorNonZero(tail);
const size_t code = nbits + 52;
- const size_t extra = copylen - (1 << nbits);
- **commands = static_cast<uint32_t>(code | (extra << 8));
+ const size_t extra = tail - ((size_t)1 << nbits);
+ **commands = (uint32_t)(code | (extra << 8));
} else {
const size_t extra = copylen - 2118;
- **commands = static_cast<uint32_t>(63 | (extra << 8));
+ **commands = (uint32_t)(63 | (extra << 8));
}
++(*commands);
}
-inline void EmitCopyLenLastDistance(size_t copylen, uint32_t** commands) {
+static BROTLI_INLINE void EmitCopyLenLastDistance(
+ size_t copylen, uint32_t** commands) {
if (copylen < 12) {
- **commands = static_cast<uint32_t>(copylen + 20);
+ **commands = (uint32_t)(copylen + 20);
++(*commands);
} else if (copylen < 72) {
- copylen -= 8;
- const size_t nbits = Log2FloorNonZero(copylen) - 1;
- const size_t prefix = copylen >> nbits;
+ const size_t tail = copylen - 8;
+ const size_t nbits = Log2FloorNonZero(tail) - 1;
+ const size_t prefix = tail >> nbits;
const size_t code = (nbits << 1) + prefix + 28;
- const size_t extra = copylen - (prefix << nbits);
- **commands = static_cast<uint32_t>(code | (extra << 8));
+ const size_t extra = tail - (prefix << nbits);
+ **commands = (uint32_t)(code | (extra << 8));
++(*commands);
} else if (copylen < 136) {
- copylen -= 8;
- const size_t code = (copylen >> 5) + 54;
- const size_t extra = copylen & 31;
- **commands = static_cast<uint32_t>(code | (extra << 8));
+ const size_t tail = copylen - 8;
+ const size_t code = (tail >> 5) + 54;
+ const size_t extra = tail & 31;
+ **commands = (uint32_t)(code | (extra << 8));
++(*commands);
**commands = 64;
++(*commands);
} else if (copylen < 2120) {
- copylen -= 72;
- const size_t nbits = Log2FloorNonZero(copylen);
+ const size_t tail = copylen - 72;
+ const size_t nbits = Log2FloorNonZero(tail);
const size_t code = nbits + 52;
- const size_t extra = copylen - (1 << nbits);
- **commands = static_cast<uint32_t>(code | (extra << 8));
+ const size_t extra = tail - ((size_t)1 << nbits);
+ **commands = (uint32_t)(code | (extra << 8));
++(*commands);
**commands = 64;
++(*commands);
} else {
const size_t extra = copylen - 2120;
- **commands = static_cast<uint32_t>(63 | (extra << 8));
+ **commands = (uint32_t)(63 | (extra << 8));
++(*commands);
**commands = 64;
++(*commands);
}
}
-inline void EmitDistance(uint32_t distance, uint32_t** commands) {
- distance += 3;
- uint32_t nbits = Log2FloorNonZero(distance) - 1;
- const uint32_t prefix = (distance >> nbits) & 1;
+static BROTLI_INLINE void EmitDistance(uint32_t distance, uint32_t** commands) {
+ uint32_t d = distance + 3;
+ uint32_t nbits = Log2FloorNonZero(d) - 1;
+ const uint32_t prefix = (d >> nbits) & 1;
const uint32_t offset = (2 + prefix) << nbits;
const uint32_t distcode = 2 * (nbits - 1) + prefix + 80;
- uint32_t extra = distance - offset;
+ uint32_t extra = d - offset;
**commands = distcode | (extra << 8);
++(*commands);
}
-// REQUIRES: len <= 1 << 20.
-static void StoreMetaBlockHeader(
- size_t len, bool is_uncompressed, size_t* storage_ix, uint8_t* storage) {
- // ISLAST
- WriteBits(1, 0, storage_ix, storage);
+/* REQUIRES: len <= 1 << 20. */
+static void BrotliStoreMetaBlockHeader(
+ size_t len, BROTLI_BOOL is_uncompressed, size_t* storage_ix,
+ uint8_t* storage) {
+ /* ISLAST */
+ BrotliWriteBits(1, 0, storage_ix, storage);
if (len <= (1U << 16)) {
- // MNIBBLES is 4
- WriteBits(2, 0, storage_ix, storage);
- WriteBits(16, len - 1, storage_ix, storage);
+ /* MNIBBLES is 4 */
+ BrotliWriteBits(2, 0, storage_ix, storage);
+ BrotliWriteBits(16, len - 1, storage_ix, storage);
} else {
- // MNIBBLES is 5
- WriteBits(2, 1, storage_ix, storage);
- WriteBits(20, len - 1, storage_ix, storage);
+ /* MNIBBLES is 5 */
+ BrotliWriteBits(2, 1, storage_ix, storage);
+ BrotliWriteBits(20, len - 1, storage_ix, storage);
}
- // ISUNCOMPRESSED
- WriteBits(1, is_uncompressed, storage_ix, storage);
+ /* ISUNCOMPRESSED */
+ BrotliWriteBits(1, (uint64_t)is_uncompressed, storage_ix, storage);
}
-static void CreateCommands(const uint8_t* input, size_t block_size,
- size_t input_size, const uint8_t* base_ip,
- int* table, size_t table_size,
- uint8_t** literals, uint32_t** commands) {
- // "ip" is the input pointer.
+static BROTLI_INLINE void CreateCommands(const uint8_t* input,
+ size_t block_size, size_t input_size, const uint8_t* base_ip, int* table,
+ size_t table_bits, uint8_t** literals, uint32_t** commands) {
+ /* "ip" is the input pointer. */
const uint8_t* ip = input;
- assert(table_size);
- assert(table_size <= (1u << 31));
- assert((table_size & (table_size - 1)) == 0); // table must be power of two
- const size_t shift = 64u - Log2FloorNonZero(table_size);
- assert(table_size - 1 == static_cast<size_t>(
- MAKE_UINT64_T(0xFFFFFFFF, 0xFFFFFF) >> shift));
+ const size_t shift = 64u - table_bits;
const uint8_t* ip_end = input + block_size;
- // "next_emit" is a pointer to the first byte that is not covered by a
- // previous copy. Bytes between "next_emit" and the start of the next copy or
- // the end of the input will be emitted as literal bytes.
+ /* "next_emit" is a pointer to the first byte that is not covered by a
+ previous copy. Bytes between "next_emit" and the start of the next copy or
+ the end of the input will be emitted as literal bytes. */
const uint8_t* next_emit = input;
int last_distance = -1;
- const size_t kInputMarginBytes = 16;
+ const size_t kInputMarginBytes = BROTLI_WINDOW_GAP;
const size_t kMinMatchLen = 6;
- if (PREDICT_TRUE(block_size >= kInputMarginBytes)) {
- // For the last block, we need to keep a 16 bytes margin so that we can be
- // sure that all distances are at most window size - 16.
- // For all other blocks, we only need to keep a margin of 5 bytes so that
- // we don't go over the block size with a copy.
- const size_t len_limit = std::min(block_size - kMinMatchLen,
- input_size - kInputMarginBytes);
+
+ if (BROTLI_PREDICT_TRUE(block_size >= kInputMarginBytes)) {
+ /* For the last block, we need to keep a 16 bytes margin so that we can be
+ sure that all distances are at most window size - 16.
+ For all other blocks, we only need to keep a margin of 5 bytes so that
+ we don't go over the block size with a copy. */
+ const size_t len_limit = BROTLI_MIN(size_t, block_size - kMinMatchLen,
+ input_size - kInputMarginBytes);
const uint8_t* ip_limit = input + len_limit;
- for (uint32_t next_hash = Hash(++ip, shift); ; ) {
- assert(next_emit < ip);
- // Step 1: Scan forward in the input looking for a 6-byte-long match.
- // If we get close to exhausting the input then goto emit_remainder.
- //
- // Heuristic match skipping: If 32 bytes are scanned with no matches
- // found, start looking only at every other byte. If 32 more bytes are
- // scanned, look at every third byte, etc.. When a match is found,
- // immediately go back to looking at every byte. This is a small loss
- // (~5% performance, ~0.1% density) for compressible data due to more
- // bookkeeping, but for non-compressible data (such as JPEG) it's a huge
- // win since the compressor quickly "realizes" the data is incompressible
- // and doesn't bother looking for matches everywhere.
- //
- // The "skip" variable keeps track of how many bytes there are since the
- // last match; dividing it by 32 (ie. right-shifting by five) gives the
- // number of bytes to move ahead for each iteration.
+ uint32_t next_hash;
+ for (next_hash = Hash(++ip, shift); ; ) {
+ /* Step 1: Scan forward in the input looking for a 6-byte-long match.
+ If we get close to exhausting the input then goto emit_remainder.
+
+ Heuristic match skipping: If 32 bytes are scanned with no matches
+ found, start looking only at every other byte. If 32 more bytes are
+ scanned, look at every third byte, etc.. When a match is found,
+ immediately go back to looking at every byte. This is a small loss
+ (~5% performance, ~0.1% density) for compressible data due to more
+ bookkeeping, but for non-compressible data (such as JPEG) it's a huge
+ win since the compressor quickly "realizes" the data is incompressible
+ and doesn't bother looking for matches everywhere.
+
+ The "skip" variable keeps track of how many bytes there are since the
+ last match; dividing it by 32 (ie. right-shifting by five) gives the
+ number of bytes to move ahead for each iteration. */
uint32_t skip = 32;
const uint8_t* next_ip = ip;
const uint8_t* candidate;
+
+ assert(next_emit < ip);
+trawl:
do {
- ip = next_ip;
uint32_t hash = next_hash;
- assert(hash == Hash(ip, shift));
uint32_t bytes_between_hash_lookups = skip++ >> 5;
+ ip = next_ip;
+ assert(hash == Hash(ip, shift));
next_ip = ip + bytes_between_hash_lookups;
- if (PREDICT_FALSE(next_ip > ip_limit)) {
+ if (BROTLI_PREDICT_FALSE(next_ip > ip_limit)) {
goto emit_remainder;
}
next_hash = Hash(next_ip, shift);
candidate = ip - last_distance;
if (IsMatch(ip, candidate)) {
- if (PREDICT_TRUE(candidate < ip)) {
- table[hash] = static_cast<int>(ip - base_ip);
+ if (BROTLI_PREDICT_TRUE(candidate < ip)) {
+ table[hash] = (int)(ip - base_ip);
break;
}
}
@@ -292,97 +306,106 @@ static void CreateCommands(const uint8_t* input, size_t block_size,
assert(candidate >= base_ip);
assert(candidate < ip);
- table[hash] = static_cast<int>(ip - base_ip);
- } while (PREDICT_TRUE(!IsMatch(ip, candidate)));
+ table[hash] = (int)(ip - base_ip);
+ } while (BROTLI_PREDICT_TRUE(!IsMatch(ip, candidate)));
+
+ /* Check copy distance. If candidate is not feasible, continue search.
+ Checking is done outside of hot loop to reduce overhead. */
+ if (ip - candidate > MAX_DISTANCE) goto trawl;
- // Step 2: Emit the found match together with the literal bytes from
- // "next_emit", and then see if we can find a next macth immediately
- // afterwards. Repeat until we find no match for the input
- // without emitting some literal bytes.
- uint64_t input_bytes;
+ /* Step 2: Emit the found match together with the literal bytes from
+ "next_emit", and then see if we can find a next match immediately
+ afterwards. Repeat until we find no match for the input
+ without emitting some literal bytes. */
{
- // We have a 6-byte match at ip, and we need to emit bytes in
- // [next_emit, ip).
+ /* We have a 6-byte match at ip, and we need to emit bytes in
+ [next_emit, ip). */
const uint8_t* base = ip;
size_t matched = 6 + FindMatchLengthWithLimit(
- candidate + 6, ip + 6, static_cast<size_t>(ip_end - ip) - 6);
+ candidate + 6, ip + 6, (size_t)(ip_end - ip) - 6);
+ int distance = (int)(base - candidate); /* > 0 */
+ int insert = (int)(base - next_emit);
ip += matched;
- int distance = static_cast<int>(base - candidate); /* > 0 */
- int insert = static_cast<int>(base - next_emit);
assert(0 == memcmp(base, candidate, matched));
- EmitInsertLen(static_cast<uint32_t>(insert), commands);
- memcpy(*literals, next_emit, static_cast<size_t>(insert));
+ EmitInsertLen((uint32_t)insert, commands);
+ memcpy(*literals, next_emit, (size_t)insert);
*literals += insert;
if (distance == last_distance) {
**commands = 64;
++(*commands);
} else {
- EmitDistance(static_cast<uint32_t>(distance), commands);
+ EmitDistance((uint32_t)distance, commands);
last_distance = distance;
}
EmitCopyLenLastDistance(matched, commands);
next_emit = ip;
- if (PREDICT_FALSE(ip >= ip_limit)) {
+ if (BROTLI_PREDICT_FALSE(ip >= ip_limit)) {
goto emit_remainder;
}
- // We could immediately start working at ip now, but to improve
- // compression we first update "table" with the hashes of some positions
- // within the last copy.
- input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 5);
- uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 5);
- prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 4);
- prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 3);
- input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
- prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 2);
- prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 1);
-
- uint32_t cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
- candidate = base_ip + table[cur_hash];
- table[cur_hash] = static_cast<int>(ip - base_ip);
+ {
+ /* We could immediately start working at ip now, but to improve
+ compression we first update "table" with the hashes of some
+ positions within the last copy. */
+ uint64_t input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 5);
+ uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+ uint32_t cur_hash;
+ table[prev_hash] = (int)(ip - base_ip - 5);
+ prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+ table[prev_hash] = (int)(ip - base_ip - 4);
+ prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
+ table[prev_hash] = (int)(ip - base_ip - 3);
+ input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
+ cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
+ prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+ table[prev_hash] = (int)(ip - base_ip - 2);
+ prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+ table[prev_hash] = (int)(ip - base_ip - 1);
+
+ candidate = base_ip + table[cur_hash];
+ table[cur_hash] = (int)(ip - base_ip);
+ }
}
- while (IsMatch(ip, candidate)) {
- // We have a 6-byte match at ip, and no need to emit any
- // literal bytes prior to ip.
+ while (ip - candidate <= MAX_DISTANCE && IsMatch(ip, candidate)) {
+ /* We have a 6-byte match at ip, and no need to emit any
+ literal bytes prior to ip. */
const uint8_t* base = ip;
size_t matched = 6 + FindMatchLengthWithLimit(
- candidate + 6, ip + 6, static_cast<size_t>(ip_end - ip) - 6);
+ candidate + 6, ip + 6, (size_t)(ip_end - ip) - 6);
ip += matched;
- last_distance = static_cast<int>(base - candidate); /* > 0 */
+ last_distance = (int)(base - candidate); /* > 0 */
assert(0 == memcmp(base, candidate, matched));
EmitCopyLen(matched, commands);
- EmitDistance(static_cast<uint32_t>(last_distance), commands);
+ EmitDistance((uint32_t)last_distance, commands);
next_emit = ip;
- if (PREDICT_FALSE(ip >= ip_limit)) {
+ if (BROTLI_PREDICT_FALSE(ip >= ip_limit)) {
goto emit_remainder;
}
- // We could immediately start working at ip now, but to improve
- // compression we first update "table" with the hashes of some positions
- // within the last copy.
- input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 5);
- uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 5);
- prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 4);
- prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 3);
- input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
- prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 2);
- prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
- table[prev_hash] = static_cast<int>(ip - base_ip - 1);
-
- uint32_t cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
- candidate = base_ip + table[cur_hash];
- table[cur_hash] = static_cast<int>(ip - base_ip);
+ {
+ /* We could immediately start working at ip now, but to improve
+ compression we first update "table" with the hashes of some
+ positions within the last copy. */
+ uint64_t input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 5);
+ uint32_t prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+ uint32_t cur_hash;
+ table[prev_hash] = (int)(ip - base_ip - 5);
+ prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+ table[prev_hash] = (int)(ip - base_ip - 4);
+ prev_hash = HashBytesAtOffset(input_bytes, 2, shift);
+ table[prev_hash] = (int)(ip - base_ip - 3);
+ input_bytes = BROTLI_UNALIGNED_LOAD64(ip - 2);
+ cur_hash = HashBytesAtOffset(input_bytes, 2, shift);
+ prev_hash = HashBytesAtOffset(input_bytes, 0, shift);
+ table[prev_hash] = (int)(ip - base_ip - 2);
+ prev_hash = HashBytesAtOffset(input_bytes, 1, shift);
+ table[prev_hash] = (int)(ip - base_ip - 1);
+
+ candidate = base_ip + table[cur_hash];
+ table[cur_hash] = (int)(ip - base_ip);
+ }
}
next_hash = Hash(++ip, shift);
@@ -391,42 +414,19 @@ static void CreateCommands(const uint8_t* input, size_t block_size,
emit_remainder:
assert(next_emit <= ip_end);
- // Emit the remaining bytes as literals.
+ /* Emit the remaining bytes as literals. */
if (next_emit < ip_end) {
- const uint32_t insert = static_cast<uint32_t>(ip_end - next_emit);
+ const uint32_t insert = (uint32_t)(ip_end - next_emit);
EmitInsertLen(insert, commands);
memcpy(*literals, next_emit, insert);
*literals += insert;
}
}
-static void StoreCommands(const uint8_t* literals, const size_t num_literals,
+static void StoreCommands(MemoryManager* m,
+ const uint8_t* literals, const size_t num_literals,
const uint32_t* commands, const size_t num_commands,
size_t* storage_ix, uint8_t* storage) {
- uint8_t lit_depths[256] = { 0 };
- uint16_t lit_bits[256] = { 0 };
- uint32_t lit_histo[256] = { 0 };
- for (size_t i = 0; i < num_literals; ++i) {
- ++lit_histo[literals[i]];
- }
- BuildAndStoreHuffmanTreeFast(lit_histo, num_literals,
- /* max_bits = */ 8,
- lit_depths, lit_bits,
- storage_ix, storage);
-
- uint8_t cmd_depths[128] = { 0 };
- uint16_t cmd_bits[128] = { 0 };
- uint32_t cmd_histo[128] = { 0 };
- for (size_t i = 0; i < num_commands; ++i) {
- ++cmd_histo[commands[i] & 0xff];
- }
- cmd_histo[1] += 1;
- cmd_histo[2] += 1;
- cmd_histo[64] += 1;
- cmd_histo[84] += 1;
- BuildAndStoreCommandPrefixCode(cmd_histo, cmd_depths, cmd_bits,
- storage_ix, storage);
-
static const uint32_t kNumExtraBits[128] = {
0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 7, 8, 9, 10, 12, 14, 24,
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4,
@@ -441,70 +441,100 @@ static void StoreCommands(const uint8_t* literals, const size_t num_literals,
1090, 2114, 6210, 22594,
};
- for (size_t i = 0; i < num_commands; ++i) {
+ uint8_t lit_depths[256];
+ uint16_t lit_bits[256];
+ uint32_t lit_histo[256] = { 0 };
+ uint8_t cmd_depths[128] = { 0 };
+ uint16_t cmd_bits[128] = { 0 };
+ uint32_t cmd_histo[128] = { 0 };
+ size_t i;
+ for (i = 0; i < num_literals; ++i) {
+ ++lit_histo[literals[i]];
+ }
+ BrotliBuildAndStoreHuffmanTreeFast(m, lit_histo, num_literals,
+ /* max_bits = */ 8,
+ lit_depths, lit_bits,
+ storage_ix, storage);
+ if (BROTLI_IS_OOM(m)) return;
+
+ for (i = 0; i < num_commands; ++i) {
+ ++cmd_histo[commands[i] & 0xff];
+ }
+ cmd_histo[1] += 1;
+ cmd_histo[2] += 1;
+ cmd_histo[64] += 1;
+ cmd_histo[84] += 1;
+ BuildAndStoreCommandPrefixCode(cmd_histo, cmd_depths, cmd_bits,
+ storage_ix, storage);
+
+ for (i = 0; i < num_commands; ++i) {
const uint32_t cmd = commands[i];
const uint32_t code = cmd & 0xff;
const uint32_t extra = cmd >> 8;
- WriteBits(cmd_depths[code], cmd_bits[code], storage_ix, storage);
- WriteBits(kNumExtraBits[code], extra, storage_ix, storage);
+ BrotliWriteBits(cmd_depths[code], cmd_bits[code], storage_ix, storage);
+ BrotliWriteBits(kNumExtraBits[code], extra, storage_ix, storage);
if (code < 24) {
const uint32_t insert = kInsertOffset[code] + extra;
- for (uint32_t j = 0; j < insert; ++j) {
+ uint32_t j;
+ for (j = 0; j < insert; ++j) {
const uint8_t lit = *literals;
- WriteBits(lit_depths[lit], lit_bits[lit], storage_ix, storage);
+ BrotliWriteBits(lit_depths[lit], lit_bits[lit], storage_ix, storage);
++literals;
}
}
}
}
-static bool ShouldCompress(const uint8_t* input, size_t input_size,
- size_t num_literals) {
- static const double kAcceptableLossForUncompressibleSpeedup = 0.02;
- static const double kMaxRatioOfLiterals =
- 1.0 - kAcceptableLossForUncompressibleSpeedup;
- if (num_literals < kMaxRatioOfLiterals * static_cast<double>(input_size)) {
- return true;
- }
- uint32_t literal_histo[256] = { 0 };
- static const uint32_t kSampleRate = 43;
- static const double kMaxEntropy =
- 8 * (1.0 - kAcceptableLossForUncompressibleSpeedup);
- const double max_total_bit_cost =
- static_cast<double>(input_size) * kMaxEntropy / kSampleRate;
- for (size_t i = 0; i < input_size; i += kSampleRate) {
- ++literal_histo[input[i]];
+/* Acceptable loss for uncompressible speedup is 2% */
+#define MIN_RATIO 0.98
+#define SAMPLE_RATE 43
+
+static BROTLI_BOOL ShouldCompress(
+ const uint8_t* input, size_t input_size, size_t num_literals) {
+ double corpus_size = (double)input_size;
+ if (num_literals < MIN_RATIO * corpus_size) {
+ return BROTLI_TRUE;
+ } else {
+ uint32_t literal_histo[256] = { 0 };
+ const double max_total_bit_cost = corpus_size * 8 * MIN_RATIO / SAMPLE_RATE;
+ size_t i;
+ for (i = 0; i < input_size; i += SAMPLE_RATE) {
+ ++literal_histo[input[i]];
+ }
+ return TO_BROTLI_BOOL(BitsEntropy(literal_histo, 256) < max_total_bit_cost);
}
- return BitsEntropy(literal_histo, 256) < max_total_bit_cost;
}
-void BrotliCompressFragmentTwoPass(const uint8_t* input, size_t input_size,
- bool is_last,
- uint32_t* command_buf, uint8_t* literal_buf,
- int* table, size_t table_size,
- size_t* storage_ix, uint8_t* storage) {
- // Save the start of the first block for position and distance computations.
+static BROTLI_INLINE void BrotliCompressFragmentTwoPassImpl(
+ MemoryManager* m, const uint8_t* input, size_t input_size,
+ BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf,
+ int* table, size_t table_bits, size_t* storage_ix, uint8_t* storage) {
+ /* Save the start of the first block for position and distance computations.
+ */
const uint8_t* base_ip = input;
while (input_size > 0) {
- size_t block_size = std::min(input_size, kCompressFragmentTwoPassBlockSize);
+ size_t block_size =
+ BROTLI_MIN(size_t, input_size, kCompressFragmentTwoPassBlockSize);
uint32_t* commands = command_buf;
uint8_t* literals = literal_buf;
- CreateCommands(input, block_size, input_size, base_ip, table, table_size,
+ size_t num_literals;
+ CreateCommands(input, block_size, input_size, base_ip, table, table_bits,
&literals, &commands);
- const size_t num_literals = static_cast<size_t>(literals - literal_buf);
- const size_t num_commands = static_cast<size_t>(commands - command_buf);
+ num_literals = (size_t)(literals - literal_buf);
if (ShouldCompress(input, block_size, num_literals)) {
- StoreMetaBlockHeader(block_size, 0, storage_ix, storage);
- // No block splits, no contexts.
- WriteBits(13, 0, storage_ix, storage);
- StoreCommands(literal_buf, num_literals, command_buf, num_commands,
+ const size_t num_commands = (size_t)(commands - command_buf);
+ BrotliStoreMetaBlockHeader(block_size, 0, storage_ix, storage);
+ /* No block splits, no contexts. */
+ BrotliWriteBits(13, 0, storage_ix, storage);
+ StoreCommands(m, literal_buf, num_literals, command_buf, num_commands,
storage_ix, storage);
+ if (BROTLI_IS_OOM(m)) return;
} else {
- // Since we did not find many backward references and the entropy of
- // the data is close to 8 bits, we can simply emit an uncompressed block.
- // This makes compression speed of uncompressible data about 3x faster.
- StoreMetaBlockHeader(block_size, 1, storage_ix, storage);
+ /* Since we did not find many backward references and the entropy of
+ the data is close to 8 bits, we can simply emit an uncompressed block.
+ This makes compression speed of uncompressible data about 3x faster. */
+ BrotliStoreMetaBlockHeader(block_size, 1, storage_ix, storage);
*storage_ix = (*storage_ix + 7u) & ~7u;
memcpy(&storage[*storage_ix >> 3], input, block_size);
*storage_ix += block_size << 3;
@@ -515,10 +545,46 @@ void BrotliCompressFragmentTwoPass(const uint8_t* input, size_t input_size,
}
if (is_last) {
- WriteBits(1, 1, storage_ix, storage); // islast
- WriteBits(1, 1, storage_ix, storage); // isempty
+ BrotliWriteBits(1, 1, storage_ix, storage); /* islast */
+ BrotliWriteBits(1, 1, storage_ix, storage); /* isempty */
*storage_ix = (*storage_ix + 7u) & ~7u;
}
}
-} // namespace brotli
+#define FOR_TABLE_BITS_(X) \
+ X(8) X(9) X(10) X(11) X(12) X(13) X(14) X(15) X(16) X(17)
+
+#define BAKE_METHOD_PARAM_(B) \
+static BROTLI_NOINLINE void BrotliCompressFragmentTwoPassImpl ## B( \
+ MemoryManager* m, const uint8_t* input, size_t input_size, \
+ BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf, \
+ int* table, size_t* storage_ix, uint8_t* storage) { \
+ BrotliCompressFragmentTwoPassImpl(m, input, input_size, is_last, command_buf,\
+ literal_buf, table, B, storage_ix, storage); \
+}
+FOR_TABLE_BITS_(BAKE_METHOD_PARAM_)
+#undef BAKE_METHOD_PARAM_
+
+void BrotliCompressFragmentTwoPass(
+ MemoryManager* m, const uint8_t* input, size_t input_size,
+ BROTLI_BOOL is_last, uint32_t* command_buf, uint8_t* literal_buf,
+ int* table, size_t table_size, size_t* storage_ix, uint8_t* storage) {
+ const size_t table_bits = Log2FloorNonZero(table_size);
+ switch (table_bits) {
+#define CASE_(B) \
+ case B: \
+ BrotliCompressFragmentTwoPassImpl ## B( \
+ m, input, input_size, is_last, command_buf, \
+ literal_buf, table, storage_ix, storage); \
+ break;
+ FOR_TABLE_BITS_(CASE_)
+#undef CASE_
+ default: assert(0); break;
+ }
+}
+
+#undef FOR_TABLE_BITS_
+
+#if defined(__cplusplus) || defined(c_plusplus)
+} /* extern "C" */
+#endif
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