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