package brotli import "io" /* Copyright 2015 Google Inc. All Rights Reserved. Distributed under MIT license. See file LICENSE for detail or copy at https://opensource.org/licenses/MIT */ /* Copyright 2015 Google Inc. All Rights Reserved. Distributed under MIT license. See file LICENSE for detail or copy at https://opensource.org/licenses/MIT */ /* Brotli state for partial streaming decoding. */ const ( BROTLI_STATE_UNINITED = iota BROTLI_STATE_LARGE_WINDOW_BITS BROTLI_STATE_INITIALIZE BROTLI_STATE_METABLOCK_BEGIN BROTLI_STATE_METABLOCK_HEADER BROTLI_STATE_METABLOCK_HEADER_2 BROTLI_STATE_CONTEXT_MODES BROTLI_STATE_COMMAND_BEGIN BROTLI_STATE_COMMAND_INNER BROTLI_STATE_COMMAND_POST_DECODE_LITERALS BROTLI_STATE_COMMAND_POST_WRAP_COPY BROTLI_STATE_UNCOMPRESSED BROTLI_STATE_METADATA BROTLI_STATE_COMMAND_INNER_WRITE BROTLI_STATE_METABLOCK_DONE BROTLI_STATE_COMMAND_POST_WRITE_1 BROTLI_STATE_COMMAND_POST_WRITE_2 BROTLI_STATE_HUFFMAN_CODE_0 BROTLI_STATE_HUFFMAN_CODE_1 BROTLI_STATE_HUFFMAN_CODE_2 BROTLI_STATE_HUFFMAN_CODE_3 BROTLI_STATE_CONTEXT_MAP_1 BROTLI_STATE_CONTEXT_MAP_2 BROTLI_STATE_TREE_GROUP BROTLI_STATE_DONE ) const ( BROTLI_STATE_METABLOCK_HEADER_NONE = iota BROTLI_STATE_METABLOCK_HEADER_EMPTY BROTLI_STATE_METABLOCK_HEADER_NIBBLES BROTLI_STATE_METABLOCK_HEADER_SIZE BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED BROTLI_STATE_METABLOCK_HEADER_RESERVED BROTLI_STATE_METABLOCK_HEADER_BYTES BROTLI_STATE_METABLOCK_HEADER_METADATA ) const ( BROTLI_STATE_UNCOMPRESSED_NONE = iota BROTLI_STATE_UNCOMPRESSED_WRITE ) const ( BROTLI_STATE_TREE_GROUP_NONE = iota BROTLI_STATE_TREE_GROUP_LOOP ) const ( BROTLI_STATE_CONTEXT_MAP_NONE = iota BROTLI_STATE_CONTEXT_MAP_READ_PREFIX BROTLI_STATE_CONTEXT_MAP_HUFFMAN BROTLI_STATE_CONTEXT_MAP_DECODE BROTLI_STATE_CONTEXT_MAP_TRANSFORM ) const ( BROTLI_STATE_HUFFMAN_NONE = iota BROTLI_STATE_HUFFMAN_SIMPLE_SIZE BROTLI_STATE_HUFFMAN_SIMPLE_READ BROTLI_STATE_HUFFMAN_SIMPLE_BUILD BROTLI_STATE_HUFFMAN_COMPLEX BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS ) const ( BROTLI_STATE_DECODE_UINT8_NONE = iota BROTLI_STATE_DECODE_UINT8_SHORT BROTLI_STATE_DECODE_UINT8_LONG ) const ( BROTLI_STATE_READ_BLOCK_LENGTH_NONE = iota BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX ) type Reader struct { src io.Reader buf []byte // scratch space for reading from src in []byte // current chunk to decode; usually aliases buf state int loop_counter int br bitReader buffer struct { u64 uint64 u8 [8]byte } buffer_length uint32 pos int max_backward_distance int max_distance int ringbuffer_size int ringbuffer_mask int dist_rb_idx int dist_rb [4]int error_code int sub_loop_counter uint32 ringbuffer []byte ringbuffer_end []byte htree_command []HuffmanCode context_lookup []byte context_map_slice []byte dist_context_map_slice []byte literal_hgroup HuffmanTreeGroup insert_copy_hgroup HuffmanTreeGroup distance_hgroup HuffmanTreeGroup block_type_trees []HuffmanCode block_len_trees []HuffmanCode trivial_literal_context int distance_context int meta_block_remaining_len int block_length_index uint32 block_length [3]uint32 num_block_types [3]uint32 block_type_rb [6]uint32 distance_postfix_bits uint32 num_direct_distance_codes uint32 distance_postfix_mask int num_dist_htrees uint32 dist_context_map []byte literal_htree []HuffmanCode dist_htree_index byte repeat_code_len uint32 prev_code_len uint32 copy_length int distance_code int rb_roundtrips uint partial_pos_out uint symbol uint32 repeat uint32 space uint32 table [32]HuffmanCode symbol_lists SymbolList symbols_lists_array [BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1 + BROTLI_NUM_COMMAND_SYMBOLS]uint16 next_symbol [32]int code_length_code_lengths [BROTLI_CODE_LENGTH_CODES]byte code_length_histo [16]uint16 htree_index int next []HuffmanCode context_index uint32 max_run_length_prefix uint32 code uint32 context_map_table [BROTLI_HUFFMAN_MAX_SIZE_272]HuffmanCode substate_metablock_header int substate_tree_group int substate_context_map int substate_uncompressed int substate_huffman int substate_decode_uint8 int substate_read_block_length int is_last_metablock uint is_uncompressed uint is_metadata uint should_wrap_ringbuffer uint canny_ringbuffer_allocation uint large_window bool size_nibbles uint window_bits uint32 new_ringbuffer_size int num_literal_htrees uint32 context_map []byte context_modes []byte dictionary *BrotliDictionary transforms *BrotliTransforms trivial_literal_contexts [8]uint32 } func BrotliDecoderStateInit(s *Reader) bool { s.error_code = 0 /* BROTLI_DECODER_NO_ERROR */ initBitReader(&s.br) s.state = BROTLI_STATE_UNINITED s.large_window = false s.substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE s.substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE s.substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE s.substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_NONE s.substate_huffman = BROTLI_STATE_HUFFMAN_NONE s.substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE s.substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE s.buffer_length = 0 s.loop_counter = 0 s.pos = 0 s.rb_roundtrips = 0 s.partial_pos_out = 0 s.block_type_trees = nil s.block_len_trees = nil s.ringbuffer = nil s.ringbuffer_size = 0 s.new_ringbuffer_size = 0 s.ringbuffer_mask = 0 s.context_map = nil s.context_modes = nil s.dist_context_map = nil s.context_map_slice = nil s.dist_context_map_slice = nil s.sub_loop_counter = 0 s.literal_hgroup.codes = nil s.literal_hgroup.htrees = nil s.insert_copy_hgroup.codes = nil s.insert_copy_hgroup.htrees = nil s.distance_hgroup.codes = nil s.distance_hgroup.htrees = nil s.is_last_metablock = 0 s.is_uncompressed = 0 s.is_metadata = 0 s.should_wrap_ringbuffer = 0 s.canny_ringbuffer_allocation = 1 s.window_bits = 0 s.max_distance = 0 s.dist_rb[0] = 16 s.dist_rb[1] = 15 s.dist_rb[2] = 11 s.dist_rb[3] = 4 s.dist_rb_idx = 0 s.block_type_trees = nil s.block_len_trees = nil s.symbol_lists.storage = s.symbols_lists_array[:] s.symbol_lists.offset = BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1 s.dictionary = BrotliGetDictionary() s.transforms = BrotliGetTransforms() return true } func BrotliDecoderStateMetablockBegin(s *Reader) { s.meta_block_remaining_len = 0 s.block_length[0] = 1 << 24 s.block_length[1] = 1 << 24 s.block_length[2] = 1 << 24 s.num_block_types[0] = 1 s.num_block_types[1] = 1 s.num_block_types[2] = 1 s.block_type_rb[0] = 1 s.block_type_rb[1] = 0 s.block_type_rb[2] = 1 s.block_type_rb[3] = 0 s.block_type_rb[4] = 1 s.block_type_rb[5] = 0 s.context_map = nil s.context_modes = nil s.dist_context_map = nil s.context_map_slice = nil s.literal_htree = nil s.dist_context_map_slice = nil s.dist_htree_index = 0 s.context_lookup = nil s.literal_hgroup.codes = nil s.literal_hgroup.htrees = nil s.insert_copy_hgroup.codes = nil s.insert_copy_hgroup.htrees = nil s.distance_hgroup.codes = nil s.distance_hgroup.htrees = nil } func BrotliDecoderStateCleanupAfterMetablock(s *Reader) { s.context_modes = nil s.context_map = nil s.dist_context_map = nil s.literal_hgroup.htrees = nil s.insert_copy_hgroup.htrees = nil s.distance_hgroup.htrees = nil } func BrotliDecoderStateCleanup(s *Reader) { BrotliDecoderStateCleanupAfterMetablock(s) s.ringbuffer = nil s.block_type_trees = nil } func BrotliDecoderHuffmanTreeGroupInit(s *Reader, group *HuffmanTreeGroup, alphabet_size uint32, max_symbol uint32, ntrees uint32) bool { var max_table_size uint = uint(kMaxHuffmanTableSize[(alphabet_size+31)>>5]) group.alphabet_size = uint16(alphabet_size) group.max_symbol = uint16(max_symbol) group.num_htrees = uint16(ntrees) group.htrees = make([][]HuffmanCode, ntrees) group.codes = make([]HuffmanCode, (uint(ntrees) * max_table_size)) return !(group.codes == nil) }