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Added Brotli compress/decompress utilities and makefiles

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This commit is contained in:
Roderick Sheeter
2013-11-19 14:32:56 -08:00
parent 1571db36a9
commit 437bbad370
29 changed files with 3267 additions and 135 deletions
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brotli/enc/encode.cc
+33 -28
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@@ -34,6 +34,18 @@
namespace brotli {
static const int kWindowBits = 22;
// To make decoding faster, we allow the decoder to write 16 bytes ahead in
// its ringbuffer, therefore the encoder has to decrease max distance by this
// amount.
static const int kDecoderRingBufferWriteAheadSlack = 16;
static const int kMaxBackwardDistance =
(1 << kWindowBits) - kDecoderRingBufferWriteAheadSlack;
static const int kMetaBlockSizeBits = 21;
static const int kRingBufferBits = 23;
static const int kRingBufferMask = (1 << kRingBufferBits) - 1;
template<int kSize>
double Entropy(const std::vector<Histogram<kSize> >& histograms) {
double retval = 0;
@@ -264,7 +276,7 @@ void EncodeCommand(const Command& cmd,
uint64_t insert_extra_bits_val =
cmd.insert_length_ - InsertLengthOffset(code);
int copy_extra_bits = CopyLengthExtraBits(code);
uint64_t copy_extra_bits_val = cmd.copy_length_ - CopyLengthOffset(code);
uint64_t copy_extra_bits_val = cmd.copy_length_code_ - CopyLengthOffset(code);
if (insert_extra_bits > 0) {
WriteBits(insert_extra_bits, insert_extra_bits_val, storage_ix, storage);
}
@@ -325,8 +337,8 @@ void ComputeCommandPrefixes(std::vector<Command>* cmds,
for (int i = 0; i < cmds->size(); ++i) {
Command* cmd = &(*cmds)[i];
cmd->command_prefix_ = CommandPrefix(cmd->insert_length_,
cmd->copy_length_);
if (cmd->copy_length_ > 0) {
cmd->copy_length_code_);
if (cmd->copy_length_code_ > 0) {
PrefixEncodeCopyDistance(cmd->distance_code_,
num_direct_distance_codes,
distance_postfix_bits,
@@ -454,7 +466,7 @@ void EncodeContextMap(const std::vector<int>& context_map,
int* storage_ix, uint8_t* storage) {
WriteBits(8, num_clusters - 1, storage_ix, storage);
if (num_clusters == 1 || num_clusters == context_map.size()) {
if (num_clusters == 1) {
return;
}
@@ -737,10 +749,10 @@ void StoreMetaBlock(const MetaBlock& mb,
}
if (*pos < end_pos && cmd.distance_prefix_ != 0xffff) {
MoveAndEncode(distance_split_code, &distance_it, storage_ix, storage);
int histogram_index = distance_it.type_;
int context = (distance_it.type_ << 2) +
((cmd.copy_length_ > 4) ? 3 : cmd.copy_length_ - 2);
histogram_index = mb.distance_context_map[context];
((cmd.copy_length_code_ > 4) ? 3 : cmd.copy_length_code_ - 2);
int histogram_index = mb.distance_context_map[context];
size_t max_distance = std::min(*pos, (size_t)kMaxBackwardDistance);
EncodeCopyDistance(cmd, distance_codes[histogram_index],
storage_ix, storage);
}
@@ -748,32 +760,21 @@ void StoreMetaBlock(const MetaBlock& mb,
}
}
static const int kWindowBits = 22;
// To make decoding faster, we allow the decoder to write 16 bytes ahead in
// its ringbuffer, therefore the encoder has to decrease max distance by this
// amount.
static const int kDecoderRingBufferWriteAheadSlack = 16;
static const int kMaxBackwardDistance =
(1 << kWindowBits) - kDecoderRingBufferWriteAheadSlack;
static const int kMetaBlockSizeBits = 21;
static const int kRingBufferBits = 23;
static const int kRingBufferMask = (1 << kRingBufferBits) - 1;
BrotliCompressor::BrotliCompressor()
: hasher_(new Hasher),
: window_bits_(kWindowBits),
hasher_(new Hasher),
dist_ringbuffer_idx_(0),
input_pos_(0),
ringbuffer_(kRingBufferBits, kMetaBlockSizeBits),
literal_cost_(1 << kRingBufferBits),
storage_ix_(0),
storage_(new uint8_t[2 << kMetaBlockSizeBits]) {
dist_ringbuffer_[0] = 4;
dist_ringbuffer_[1] = 11;
dist_ringbuffer_[2] = 15;
dist_ringbuffer_[3] = 16;
storage_[0] = 0;
}
dist_ringbuffer_[0] = 4;
dist_ringbuffer_[1] = 11;
dist_ringbuffer_[2] = 15;
dist_ringbuffer_[3] = 16;
storage_[0] = 0;
}
BrotliCompressor::~BrotliCompressor() {
delete hasher_;
@@ -784,8 +785,12 @@ void BrotliCompressor::WriteStreamHeader() {
// Don't encode input size.
WriteBits(3, 0, &storage_ix_, storage_);
// Encode window size.
WriteBits(1, 1, &storage_ix_, storage_);
WriteBits(3, kWindowBits - 17, &storage_ix_, storage_);
if (window_bits_ == 16) {
WriteBits(1, 0, &storage_ix_, storage_);
} else {
WriteBits(1, 1, &storage_ix_, storage_);
WriteBits(3, window_bits_ - 17, &storage_ix_, storage_);
}
}
void BrotliCompressor::WriteMetaBlock(const size_t input_size,