Index: third_party/brotli/enc/histogram.c |
diff --git a/third_party/brotli/enc/histogram.cc b/third_party/brotli/enc/histogram.c |
similarity index 19% |
rename from third_party/brotli/enc/histogram.cc |
rename to third_party/brotli/enc/histogram.c |
index 9d733d805544b059893b91865331ebe44973b30b..a8f0413024e4601feeb32303f4a1e838e884a66c 100644 |
--- a/third_party/brotli/enc/histogram.cc |
+++ b/third_party/brotli/enc/histogram.c |
@@ -4,64 +4,92 @@ |
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
*/ |
-// Build per-context histograms of literals, commands and distance codes. |
+/* Build per-context histograms of literals, commands and distance codes. */ |
#include "./histogram.h" |
-#include <cmath> |
- |
#include "./block_splitter.h" |
#include "./command.h" |
#include "./context.h" |
-#include "./prefix.h" |
-namespace brotli { |
+#if defined(__cplusplus) || defined(c_plusplus) |
+extern "C" { |
+#endif |
+ |
+typedef struct BlockSplitIterator { |
+ const BlockSplit* split_; /* Not owned. */ |
+ size_t idx_; |
+ size_t type_; |
+ size_t length_; |
+} BlockSplitIterator; |
+ |
+static void InitBlockSplitIterator(BlockSplitIterator* self, |
+ const BlockSplit* split) { |
+ self->split_ = split; |
+ self->idx_ = 0; |
+ self->type_ = 0; |
+ self->length_ = split->lengths ? split->lengths[0] : 0; |
+} |
+ |
+static void BlockSplitIteratorNext(BlockSplitIterator* self) { |
+ if (self->length_ == 0) { |
+ ++self->idx_; |
+ self->type_ = self->split_->types[self->idx_]; |
+ self->length_ = self->split_->lengths[self->idx_]; |
+ } |
+ --self->length_; |
+} |
-void BuildHistograms( |
- const Command* cmds, |
- const size_t num_commands, |
- const BlockSplit& literal_split, |
- const BlockSplit& insert_and_copy_split, |
- const BlockSplit& dist_split, |
- const uint8_t* ringbuffer, |
- size_t start_pos, |
- size_t mask, |
- uint8_t prev_byte, |
- uint8_t prev_byte2, |
- const std::vector<ContextType>& context_modes, |
- std::vector<HistogramLiteral>* literal_histograms, |
- std::vector<HistogramCommand>* insert_and_copy_histograms, |
- std::vector<HistogramDistance>* copy_dist_histograms) { |
+void BrotliBuildHistogramsWithContext( |
+ const Command* cmds, const size_t num_commands, |
+ const BlockSplit* literal_split, const BlockSplit* insert_and_copy_split, |
+ const BlockSplit* dist_split, const uint8_t* ringbuffer, size_t start_pos, |
+ size_t mask, uint8_t prev_byte, uint8_t prev_byte2, |
+ const ContextType* context_modes, HistogramLiteral* literal_histograms, |
+ HistogramCommand* insert_and_copy_histograms, |
+ HistogramDistance* copy_dist_histograms) { |
size_t pos = start_pos; |
- BlockSplitIterator literal_it(literal_split); |
- BlockSplitIterator insert_and_copy_it(insert_and_copy_split); |
- BlockSplitIterator dist_it(dist_split); |
- for (size_t i = 0; i < num_commands; ++i) { |
- const Command &cmd = cmds[i]; |
- insert_and_copy_it.Next(); |
- (*insert_and_copy_histograms)[insert_and_copy_it.type_].Add( |
- cmd.cmd_prefix_); |
- for (size_t j = cmd.insert_len_; j != 0; --j) { |
- literal_it.Next(); |
- size_t context = (literal_it.type_ << kLiteralContextBits) + |
+ BlockSplitIterator literal_it; |
+ BlockSplitIterator insert_and_copy_it; |
+ BlockSplitIterator dist_it; |
+ size_t i; |
+ |
+ InitBlockSplitIterator(&literal_it, literal_split); |
+ InitBlockSplitIterator(&insert_and_copy_it, insert_and_copy_split); |
+ InitBlockSplitIterator(&dist_it, dist_split); |
+ for (i = 0; i < num_commands; ++i) { |
+ const Command* cmd = &cmds[i]; |
+ size_t j; |
+ BlockSplitIteratorNext(&insert_and_copy_it); |
+ HistogramAddCommand(&insert_and_copy_histograms[insert_and_copy_it.type_], |
+ cmd->cmd_prefix_); |
+ for (j = cmd->insert_len_; j != 0; --j) { |
+ size_t context; |
+ BlockSplitIteratorNext(&literal_it); |
+ context = (literal_it.type_ << BROTLI_LITERAL_CONTEXT_BITS) + |
Context(prev_byte, prev_byte2, context_modes[literal_it.type_]); |
- (*literal_histograms)[context].Add(ringbuffer[pos & mask]); |
+ HistogramAddLiteral(&literal_histograms[context], |
+ ringbuffer[pos & mask]); |
prev_byte2 = prev_byte; |
prev_byte = ringbuffer[pos & mask]; |
++pos; |
} |
- pos += cmd.copy_len(); |
- if (cmd.copy_len()) { |
+ pos += CommandCopyLen(cmd); |
+ if (CommandCopyLen(cmd)) { |
prev_byte2 = ringbuffer[(pos - 2) & mask]; |
prev_byte = ringbuffer[(pos - 1) & mask]; |
- if (cmd.cmd_prefix_ >= 128) { |
- dist_it.Next(); |
- size_t context = (dist_it.type_ << kDistanceContextBits) + |
- cmd.DistanceContext(); |
- (*copy_dist_histograms)[context].Add(cmd.dist_prefix_); |
+ if (cmd->cmd_prefix_ >= 128) { |
+ size_t context; |
+ BlockSplitIteratorNext(&dist_it); |
+ context = (dist_it.type_ << BROTLI_DISTANCE_CONTEXT_BITS) + |
+ CommandDistanceContext(cmd); |
+ HistogramAddDistance(©_dist_histograms[context], |
+ cmd->dist_prefix_); |
} |
} |
} |
} |
-} // namespace brotli |
+#if defined(__cplusplus) || defined(c_plusplus) |
+} /* extern "C" */ |
+#endif |