Added brotli enc/ and tools/ directories.

third_party/brotli/enc/metablock.h

+/* Copyright 2015 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+// Algorithms for distributing the literals and commands of a metablock between
+// block types and contexts.
+
+#ifndef BROTLI_ENC_METABLOCK_H_
+#define BROTLI_ENC_METABLOCK_H_
+
+#include <vector>
+
+#include "./command.h"
+#include "./histogram.h"
+
+namespace brotli {
+
+struct BlockSplit {
+  BlockSplit(void) : num_types(0) {}
+
+  size_t num_types;
+  std::vector<uint8_t> types;
+  std::vector<uint32_t> lengths;
+};
+
+struct MetaBlockSplit {
+  BlockSplit literal_split;
+  BlockSplit command_split;
+  BlockSplit distance_split;
+  std::vector<uint32_t> literal_context_map;
+  std::vector<uint32_t> distance_context_map;
+  std::vector<HistogramLiteral> literal_histograms;
+  std::vector<HistogramCommand> command_histograms;
+  std::vector<HistogramDistance> distance_histograms;
+};
+
+// Uses the slow shortest-path block splitter and does context clustering.
+void BuildMetaBlock(const uint8_t* ringbuffer,
+                    const size_t pos,
+                    const size_t mask,
+                    uint8_t prev_byte,
+                    uint8_t prev_byte2,
+                    const Command* cmds,
+                    size_t num_commands,
+                    ContextType literal_context_mode,
+                    MetaBlockSplit* mb);
+
+// Uses a fast greedy block splitter that tries to merge current block with the
+// last or the second last block and does not do any context modeling.
+void BuildMetaBlockGreedy(const uint8_t* ringbuffer,
+                          size_t pos,
+                          size_t mask,
+                          const Command *commands,
+                          size_t n_commands,
+                          MetaBlockSplit* mb);
+
+// Uses a fast greedy block splitter that tries to merge current block with the
+// last or the second last block and uses a static context clustering which
+// is the same for all block types.
+void BuildMetaBlockGreedyWithContexts(const uint8_t* ringbuffer,
+                                      size_t pos,
+                                      size_t mask,
+                                      uint8_t prev_byte,
+                                      uint8_t prev_byte2,
+                                      ContextType literal_context_mode,
+                                      size_t num_contexts,
+                                      const uint32_t* static_context_map,
+                                      const Command *commands,
+                                      size_t n_commands,
+                                      MetaBlockSplit* mb);
+
+void OptimizeHistograms(size_t num_direct_distance_codes,
+                        size_t distance_postfix_bits,
+                        MetaBlockSplit* mb);
+
+}  // namespace brotli
+
+#endif  // BROTLI_ENC_METABLOCK_H_