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1301 lines
42 KiB
1301 lines
42 KiB
package brotli
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import (
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"math"
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"sync"
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)
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const maxHuffmanTreeSize = (2*numCommandSymbols + 1)
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/* The maximum size of Huffman dictionary for distances assuming that
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NPOSTFIX = 0 and NDIRECT = 0. */
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const maxSimpleDistanceAlphabetSize = 140
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/* Represents the range of values belonging to a prefix code:
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[offset, offset + 2^nbits) */
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type prefixCodeRange struct {
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offset uint32
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nbits uint32
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}
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var kBlockLengthPrefixCode = [numBlockLenSymbols]prefixCodeRange{
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prefixCodeRange{1, 2},
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prefixCodeRange{5, 2},
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prefixCodeRange{9, 2},
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prefixCodeRange{13, 2},
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prefixCodeRange{17, 3},
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prefixCodeRange{25, 3},
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prefixCodeRange{33, 3},
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prefixCodeRange{41, 3},
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prefixCodeRange{49, 4},
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prefixCodeRange{65, 4},
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prefixCodeRange{81, 4},
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prefixCodeRange{97, 4},
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prefixCodeRange{113, 5},
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prefixCodeRange{145, 5},
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prefixCodeRange{177, 5},
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prefixCodeRange{209, 5},
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prefixCodeRange{241, 6},
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prefixCodeRange{305, 6},
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prefixCodeRange{369, 7},
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prefixCodeRange{497, 8},
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prefixCodeRange{753, 9},
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prefixCodeRange{1265, 10},
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prefixCodeRange{2289, 11},
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prefixCodeRange{4337, 12},
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prefixCodeRange{8433, 13},
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prefixCodeRange{16625, 24},
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}
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func blockLengthPrefixCode(len uint32) uint32 {
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var code uint32
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if len >= 177 {
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if len >= 753 {
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code = 20
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} else {
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code = 14
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}
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} else if len >= 41 {
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code = 7
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} else {
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code = 0
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}
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for code < (numBlockLenSymbols-1) && len >= kBlockLengthPrefixCode[code+1].offset {
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code++
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}
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return code
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}
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func getBlockLengthPrefixCode(len uint32, code *uint, n_extra *uint32, extra *uint32) {
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*code = uint(blockLengthPrefixCode(uint32(len)))
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*n_extra = kBlockLengthPrefixCode[*code].nbits
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*extra = len - kBlockLengthPrefixCode[*code].offset
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}
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type blockTypeCodeCalculator struct {
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last_type uint
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second_last_type uint
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}
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func initBlockTypeCodeCalculator(self *blockTypeCodeCalculator) {
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self.last_type = 1
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self.second_last_type = 0
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}
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func nextBlockTypeCode(calculator *blockTypeCodeCalculator, type_ byte) uint {
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var type_code uint
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if uint(type_) == calculator.last_type+1 {
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type_code = 1
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} else if uint(type_) == calculator.second_last_type {
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type_code = 0
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} else {
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type_code = uint(type_) + 2
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}
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calculator.second_last_type = calculator.last_type
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calculator.last_type = uint(type_)
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return type_code
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}
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/* |nibblesbits| represents the 2 bits to encode MNIBBLES (0-3)
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REQUIRES: length > 0
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REQUIRES: length <= (1 << 24) */
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func encodeMlen(length uint, bits *uint64, numbits *uint, nibblesbits *uint64) {
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var lg uint
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if length == 1 {
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lg = 1
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} else {
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lg = uint(log2FloorNonZero(uint(uint32(length-1)))) + 1
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}
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var tmp uint
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if lg < 16 {
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tmp = 16
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} else {
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tmp = (lg + 3)
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}
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var mnibbles uint = tmp / 4
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assert(length > 0)
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assert(length <= 1<<24)
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assert(lg <= 24)
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*nibblesbits = uint64(mnibbles) - 4
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*numbits = mnibbles * 4
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*bits = uint64(length) - 1
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}
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func storeCommandExtra(cmd *command, storage_ix *uint, storage []byte) {
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var copylen_code uint32 = commandCopyLenCode(cmd)
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var inscode uint16 = getInsertLengthCode(uint(cmd.insert_len_))
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var copycode uint16 = getCopyLengthCode(uint(copylen_code))
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var insnumextra uint32 = getInsertExtra(inscode)
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var insextraval uint64 = uint64(cmd.insert_len_) - uint64(getInsertBase(inscode))
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var copyextraval uint64 = uint64(copylen_code) - uint64(getCopyBase(copycode))
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var bits uint64 = copyextraval<<insnumextra | insextraval
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writeBits(uint(insnumextra+getCopyExtra(copycode)), bits, storage_ix, storage)
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}
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/* Data structure that stores almost everything that is needed to encode each
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block switch command. */
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type blockSplitCode struct {
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type_code_calculator blockTypeCodeCalculator
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type_depths [maxBlockTypeSymbols]byte
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type_bits [maxBlockTypeSymbols]uint16
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length_depths [numBlockLenSymbols]byte
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length_bits [numBlockLenSymbols]uint16
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}
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/* Stores a number between 0 and 255. */
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func storeVarLenUint8(n uint, storage_ix *uint, storage []byte) {
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if n == 0 {
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writeBits(1, 0, storage_ix, storage)
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} else {
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var nbits uint = uint(log2FloorNonZero(n))
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writeBits(1, 1, storage_ix, storage)
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writeBits(3, uint64(nbits), storage_ix, storage)
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writeBits(nbits, uint64(n)-(uint64(uint(1))<<nbits), storage_ix, storage)
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}
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}
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/* Stores the compressed meta-block header.
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REQUIRES: length > 0
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REQUIRES: length <= (1 << 24) */
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func storeCompressedMetaBlockHeader(is_final_block bool, length uint, storage_ix *uint, storage []byte) {
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var lenbits uint64
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var nlenbits uint
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var nibblesbits uint64
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var is_final uint64
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if is_final_block {
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is_final = 1
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} else {
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is_final = 0
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}
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/* Write ISLAST bit. */
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writeBits(1, is_final, storage_ix, storage)
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/* Write ISEMPTY bit. */
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if is_final_block {
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writeBits(1, 0, storage_ix, storage)
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}
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encodeMlen(length, &lenbits, &nlenbits, &nibblesbits)
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writeBits(2, nibblesbits, storage_ix, storage)
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writeBits(nlenbits, lenbits, storage_ix, storage)
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if !is_final_block {
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/* Write ISUNCOMPRESSED bit. */
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writeBits(1, 0, storage_ix, storage)
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}
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}
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/* Stores the uncompressed meta-block header.
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REQUIRES: length > 0
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REQUIRES: length <= (1 << 24) */
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func storeUncompressedMetaBlockHeader(length uint, storage_ix *uint, storage []byte) {
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var lenbits uint64
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var nlenbits uint
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var nibblesbits uint64
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/* Write ISLAST bit.
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Uncompressed block cannot be the last one, so set to 0. */
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writeBits(1, 0, storage_ix, storage)
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encodeMlen(length, &lenbits, &nlenbits, &nibblesbits)
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writeBits(2, nibblesbits, storage_ix, storage)
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writeBits(nlenbits, lenbits, storage_ix, storage)
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/* Write ISUNCOMPRESSED bit. */
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writeBits(1, 1, storage_ix, storage)
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}
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var storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder = [codeLengthCodes]byte{1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15}
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var storeHuffmanTreeOfHuffmanTreeToBitMask_kHuffmanBitLengthHuffmanCodeSymbols = [6]byte{0, 7, 3, 2, 1, 15}
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var storeHuffmanTreeOfHuffmanTreeToBitMask_kHuffmanBitLengthHuffmanCodeBitLengths = [6]byte{2, 4, 3, 2, 2, 4}
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func storeHuffmanTreeOfHuffmanTreeToBitMask(num_codes int, code_length_bitdepth []byte, storage_ix *uint, storage []byte) {
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var skip_some uint = 0
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var codes_to_store uint = codeLengthCodes
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/* The bit lengths of the Huffman code over the code length alphabet
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are compressed with the following static Huffman code:
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Symbol Code
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------ ----
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0 00
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1 1110
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2 110
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3 01
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4 10
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5 1111 */
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/* Throw away trailing zeros: */
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if num_codes > 1 {
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for ; codes_to_store > 0; codes_to_store-- {
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if code_length_bitdepth[storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder[codes_to_store-1]] != 0 {
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break
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}
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}
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}
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if code_length_bitdepth[storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder[0]] == 0 && code_length_bitdepth[storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder[1]] == 0 {
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skip_some = 2 /* skips two. */
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if code_length_bitdepth[storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder[2]] == 0 {
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skip_some = 3 /* skips three. */
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}
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}
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writeBits(2, uint64(skip_some), storage_ix, storage)
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{
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var i uint
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for i = skip_some; i < codes_to_store; i++ {
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var l uint = uint(code_length_bitdepth[storeHuffmanTreeOfHuffmanTreeToBitMask_kStorageOrder[i]])
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writeBits(uint(storeHuffmanTreeOfHuffmanTreeToBitMask_kHuffmanBitLengthHuffmanCodeBitLengths[l]), uint64(storeHuffmanTreeOfHuffmanTreeToBitMask_kHuffmanBitLengthHuffmanCodeSymbols[l]), storage_ix, storage)
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}
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}
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}
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func storeHuffmanTreeToBitMask(huffman_tree_size uint, huffman_tree []byte, huffman_tree_extra_bits []byte, code_length_bitdepth []byte, code_length_bitdepth_symbols []uint16, storage_ix *uint, storage []byte) {
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var i uint
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for i = 0; i < huffman_tree_size; i++ {
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var ix uint = uint(huffman_tree[i])
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writeBits(uint(code_length_bitdepth[ix]), uint64(code_length_bitdepth_symbols[ix]), storage_ix, storage)
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/* Extra bits */
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switch ix {
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case repeatPreviousCodeLength:
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writeBits(2, uint64(huffman_tree_extra_bits[i]), storage_ix, storage)
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case repeatZeroCodeLength:
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writeBits(3, uint64(huffman_tree_extra_bits[i]), storage_ix, storage)
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}
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}
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}
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func storeSimpleHuffmanTree(depths []byte, symbols []uint, num_symbols uint, max_bits uint, storage_ix *uint, storage []byte) {
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/* value of 1 indicates a simple Huffman code */
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writeBits(2, 1, storage_ix, storage)
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writeBits(2, uint64(num_symbols)-1, storage_ix, storage) /* NSYM - 1 */
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{
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/* Sort */
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var i uint
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for i = 0; i < num_symbols; i++ {
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var j uint
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for j = i + 1; j < num_symbols; j++ {
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if depths[symbols[j]] < depths[symbols[i]] {
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var tmp uint = symbols[j]
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symbols[j] = symbols[i]
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symbols[i] = tmp
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}
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}
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}
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}
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if num_symbols == 2 {
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writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
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} else if num_symbols == 3 {
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writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[2]), storage_ix, storage)
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} else {
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writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[2]), storage_ix, storage)
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writeBits(max_bits, uint64(symbols[3]), storage_ix, storage)
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/* tree-select */
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var tmp int
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if depths[symbols[0]] == 1 {
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tmp = 1
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} else {
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tmp = 0
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}
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writeBits(1, uint64(tmp), storage_ix, storage)
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}
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}
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/* num = alphabet size
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depths = symbol depths */
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func storeHuffmanTree(depths []byte, num uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
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var huffman_tree [numCommandSymbols]byte
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var huffman_tree_extra_bits [numCommandSymbols]byte
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var huffman_tree_size uint = 0
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var code_length_bitdepth = [codeLengthCodes]byte{0}
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var code_length_bitdepth_symbols [codeLengthCodes]uint16
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var huffman_tree_histogram = [codeLengthCodes]uint32{0}
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var i uint
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var num_codes int = 0
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/* Write the Huffman tree into the brotli-representation.
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The command alphabet is the largest, so this allocation will fit all
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alphabets. */
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var code uint = 0
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assert(num <= numCommandSymbols)
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writeHuffmanTree(depths, num, &huffman_tree_size, huffman_tree[:], huffman_tree_extra_bits[:])
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/* Calculate the statistics of the Huffman tree in brotli-representation. */
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for i = 0; i < huffman_tree_size; i++ {
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huffman_tree_histogram[huffman_tree[i]]++
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}
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for i = 0; i < codeLengthCodes; i++ {
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if huffman_tree_histogram[i] != 0 {
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if num_codes == 0 {
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code = i
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num_codes = 1
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} else if num_codes == 1 {
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num_codes = 2
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break
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}
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}
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}
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/* Calculate another Huffman tree to use for compressing both the
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earlier Huffman tree with. */
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createHuffmanTree(huffman_tree_histogram[:], codeLengthCodes, 5, tree, code_length_bitdepth[:])
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convertBitDepthsToSymbols(code_length_bitdepth[:], codeLengthCodes, code_length_bitdepth_symbols[:])
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/* Now, we have all the data, let's start storing it */
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storeHuffmanTreeOfHuffmanTreeToBitMask(num_codes, code_length_bitdepth[:], storage_ix, storage)
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if num_codes == 1 {
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code_length_bitdepth[code] = 0
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}
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/* Store the real Huffman tree now. */
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storeHuffmanTreeToBitMask(huffman_tree_size, huffman_tree[:], huffman_tree_extra_bits[:], code_length_bitdepth[:], code_length_bitdepth_symbols[:], storage_ix, storage)
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}
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/* Builds a Huffman tree from histogram[0:length] into depth[0:length] and
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bits[0:length] and stores the encoded tree to the bit stream. */
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func buildAndStoreHuffmanTree(histogram []uint32, histogram_length uint, alphabet_size uint, tree []huffmanTree, depth []byte, bits []uint16, storage_ix *uint, storage []byte) {
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var count uint = 0
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var s4 = [4]uint{0}
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var i uint
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var max_bits uint = 0
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for i = 0; i < histogram_length; i++ {
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if histogram[i] != 0 {
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if count < 4 {
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s4[count] = i
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} else if count > 4 {
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break
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}
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count++
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}
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}
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{
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var max_bits_counter uint = alphabet_size - 1
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for max_bits_counter != 0 {
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max_bits_counter >>= 1
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max_bits++
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}
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}
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if count <= 1 {
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writeBits(4, 1, storage_ix, storage)
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writeBits(max_bits, uint64(s4[0]), storage_ix, storage)
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depth[s4[0]] = 0
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bits[s4[0]] = 0
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return
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}
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for i := 0; i < int(histogram_length); i++ {
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depth[i] = 0
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}
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createHuffmanTree(histogram, histogram_length, 15, tree, depth)
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convertBitDepthsToSymbols(depth, histogram_length, bits)
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if count <= 4 {
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storeSimpleHuffmanTree(depth, s4[:], count, max_bits, storage_ix, storage)
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} else {
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storeHuffmanTree(depth, histogram_length, tree, storage_ix, storage)
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}
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}
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func sortHuffmanTree1(v0 huffmanTree, v1 huffmanTree) bool {
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return v0.total_count_ < v1.total_count_
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}
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var huffmanTreePool sync.Pool
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func buildAndStoreHuffmanTreeFast(histogram []uint32, histogram_total uint, max_bits uint, depth []byte, bits []uint16, storage_ix *uint, storage []byte) {
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var count uint = 0
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var symbols = [4]uint{0}
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var length uint = 0
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var total uint = histogram_total
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for total != 0 {
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if histogram[length] != 0 {
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if count < 4 {
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symbols[count] = length
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}
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count++
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total -= uint(histogram[length])
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}
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length++
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}
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if count <= 1 {
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writeBits(4, 1, storage_ix, storage)
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writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
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depth[symbols[0]] = 0
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bits[symbols[0]] = 0
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return
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}
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for i := 0; i < int(length); i++ {
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depth[i] = 0
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}
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{
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var max_tree_size uint = 2*length + 1
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tree, _ := huffmanTreePool.Get().(*[]huffmanTree)
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if tree == nil || cap(*tree) < int(max_tree_size) {
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tmp := make([]huffmanTree, max_tree_size)
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tree = &tmp
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} else {
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*tree = (*tree)[:max_tree_size]
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}
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var count_limit uint32
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for count_limit = 1; ; count_limit *= 2 {
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var node int = 0
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var l uint
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for l = length; l != 0; {
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l--
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if histogram[l] != 0 {
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if histogram[l] >= count_limit {
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initHuffmanTree(&(*tree)[node:][0], histogram[l], -1, int16(l))
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} else {
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initHuffmanTree(&(*tree)[node:][0], count_limit, -1, int16(l))
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}
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node++
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}
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}
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{
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var n int = node
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/* Points to the next leaf node. */ /* Points to the next non-leaf node. */
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var sentinel huffmanTree
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var i int = 0
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var j int = n + 1
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var k int
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|
|
sortHuffmanTreeItems(*tree, uint(n), huffmanTreeComparator(sortHuffmanTree1))
|
|
|
|
/* The nodes are:
|
|
[0, n): the sorted leaf nodes that we start with.
|
|
[n]: we add a sentinel here.
|
|
[n + 1, 2n): new parent nodes are added here, starting from
|
|
(n+1). These are naturally in ascending order.
|
|
[2n]: we add a sentinel at the end as well.
|
|
There will be (2n+1) elements at the end. */
|
|
initHuffmanTree(&sentinel, math.MaxUint32, -1, -1)
|
|
|
|
(*tree)[node] = sentinel
|
|
node++
|
|
(*tree)[node] = sentinel
|
|
node++
|
|
|
|
for k = n - 1; k > 0; k-- {
|
|
var left int
|
|
var right int
|
|
if (*tree)[i].total_count_ <= (*tree)[j].total_count_ {
|
|
left = i
|
|
i++
|
|
} else {
|
|
left = j
|
|
j++
|
|
}
|
|
|
|
if (*tree)[i].total_count_ <= (*tree)[j].total_count_ {
|
|
right = i
|
|
i++
|
|
} else {
|
|
right = j
|
|
j++
|
|
}
|
|
|
|
/* The sentinel node becomes the parent node. */
|
|
(*tree)[node-1].total_count_ = (*tree)[left].total_count_ + (*tree)[right].total_count_
|
|
|
|
(*tree)[node-1].index_left_ = int16(left)
|
|
(*tree)[node-1].index_right_or_value_ = int16(right)
|
|
|
|
/* Add back the last sentinel node. */
|
|
(*tree)[node] = sentinel
|
|
node++
|
|
}
|
|
|
|
if setDepth(2*n-1, *tree, depth, 14) {
|
|
/* We need to pack the Huffman tree in 14 bits. If this was not
|
|
successful, add fake entities to the lowest values and retry. */
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
huffmanTreePool.Put(tree)
|
|
}
|
|
|
|
convertBitDepthsToSymbols(depth, length, bits)
|
|
if count <= 4 {
|
|
var i uint
|
|
|
|
/* value of 1 indicates a simple Huffman code */
|
|
writeBits(2, 1, storage_ix, storage)
|
|
|
|
writeBits(2, uint64(count)-1, storage_ix, storage) /* NSYM - 1 */
|
|
|
|
/* Sort */
|
|
for i = 0; i < count; i++ {
|
|
var j uint
|
|
for j = i + 1; j < count; j++ {
|
|
if depth[symbols[j]] < depth[symbols[i]] {
|
|
var tmp uint = symbols[j]
|
|
symbols[j] = symbols[i]
|
|
symbols[i] = tmp
|
|
}
|
|
}
|
|
}
|
|
|
|
if count == 2 {
|
|
writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
|
|
} else if count == 3 {
|
|
writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[2]), storage_ix, storage)
|
|
} else {
|
|
writeBits(max_bits, uint64(symbols[0]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[1]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[2]), storage_ix, storage)
|
|
writeBits(max_bits, uint64(symbols[3]), storage_ix, storage)
|
|
|
|
/* tree-select */
|
|
var tmp int
|
|
if depth[symbols[0]] == 1 {
|
|
tmp = 1
|
|
} else {
|
|
tmp = 0
|
|
}
|
|
writeBits(1, uint64(tmp), storage_ix, storage)
|
|
}
|
|
} else {
|
|
var previous_value byte = 8
|
|
var i uint
|
|
|
|
/* Complex Huffman Tree */
|
|
storeStaticCodeLengthCode(storage_ix, storage)
|
|
|
|
/* Actual RLE coding. */
|
|
for i = 0; i < length; {
|
|
var value byte = depth[i]
|
|
var reps uint = 1
|
|
var k uint
|
|
for k = i + 1; k < length && depth[k] == value; k++ {
|
|
reps++
|
|
}
|
|
|
|
i += reps
|
|
if value == 0 {
|
|
writeBits(uint(kZeroRepsDepth[reps]), kZeroRepsBits[reps], storage_ix, storage)
|
|
} else {
|
|
if previous_value != value {
|
|
writeBits(uint(kCodeLengthDepth[value]), uint64(kCodeLengthBits[value]), storage_ix, storage)
|
|
reps--
|
|
}
|
|
|
|
if reps < 3 {
|
|
for reps != 0 {
|
|
reps--
|
|
writeBits(uint(kCodeLengthDepth[value]), uint64(kCodeLengthBits[value]), storage_ix, storage)
|
|
}
|
|
} else {
|
|
reps -= 3
|
|
writeBits(uint(kNonZeroRepsDepth[reps]), kNonZeroRepsBits[reps], storage_ix, storage)
|
|
}
|
|
|
|
previous_value = value
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func indexOf(v []byte, v_size uint, value byte) uint {
|
|
var i uint = 0
|
|
for ; i < v_size; i++ {
|
|
if v[i] == value {
|
|
return i
|
|
}
|
|
}
|
|
|
|
return i
|
|
}
|
|
|
|
func moveToFront(v []byte, index uint) {
|
|
var value byte = v[index]
|
|
var i uint
|
|
for i = index; i != 0; i-- {
|
|
v[i] = v[i-1]
|
|
}
|
|
|
|
v[0] = value
|
|
}
|
|
|
|
func moveToFrontTransform(v_in []uint32, v_size uint, v_out []uint32) {
|
|
var i uint
|
|
var mtf [256]byte
|
|
var max_value uint32
|
|
if v_size == 0 {
|
|
return
|
|
}
|
|
|
|
max_value = v_in[0]
|
|
for i = 1; i < v_size; i++ {
|
|
if v_in[i] > max_value {
|
|
max_value = v_in[i]
|
|
}
|
|
}
|
|
|
|
assert(max_value < 256)
|
|
for i = 0; uint32(i) <= max_value; i++ {
|
|
mtf[i] = byte(i)
|
|
}
|
|
{
|
|
var mtf_size uint = uint(max_value + 1)
|
|
for i = 0; i < v_size; i++ {
|
|
var index uint = indexOf(mtf[:], mtf_size, byte(v_in[i]))
|
|
assert(index < mtf_size)
|
|
v_out[i] = uint32(index)
|
|
moveToFront(mtf[:], index)
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Finds runs of zeros in v[0..in_size) and replaces them with a prefix code of
|
|
the run length plus extra bits (lower 9 bits is the prefix code and the rest
|
|
are the extra bits). Non-zero values in v[] are shifted by
|
|
*max_length_prefix. Will not create prefix codes bigger than the initial
|
|
value of *max_run_length_prefix. The prefix code of run length L is simply
|
|
Log2Floor(L) and the number of extra bits is the same as the prefix code. */
|
|
func runLengthCodeZeros(in_size uint, v []uint32, out_size *uint, max_run_length_prefix *uint32) {
|
|
var max_reps uint32 = 0
|
|
var i uint
|
|
var max_prefix uint32
|
|
for i = 0; i < in_size; {
|
|
var reps uint32 = 0
|
|
for ; i < in_size && v[i] != 0; i++ {
|
|
}
|
|
for ; i < in_size && v[i] == 0; i++ {
|
|
reps++
|
|
}
|
|
|
|
max_reps = brotli_max_uint32_t(reps, max_reps)
|
|
}
|
|
|
|
if max_reps > 0 {
|
|
max_prefix = log2FloorNonZero(uint(max_reps))
|
|
} else {
|
|
max_prefix = 0
|
|
}
|
|
max_prefix = brotli_min_uint32_t(max_prefix, *max_run_length_prefix)
|
|
*max_run_length_prefix = max_prefix
|
|
*out_size = 0
|
|
for i = 0; i < in_size; {
|
|
assert(*out_size <= i)
|
|
if v[i] != 0 {
|
|
v[*out_size] = v[i] + *max_run_length_prefix
|
|
i++
|
|
(*out_size)++
|
|
} else {
|
|
var reps uint32 = 1
|
|
var k uint
|
|
for k = i + 1; k < in_size && v[k] == 0; k++ {
|
|
reps++
|
|
}
|
|
|
|
i += uint(reps)
|
|
for reps != 0 {
|
|
if reps < 2<<max_prefix {
|
|
var run_length_prefix uint32 = log2FloorNonZero(uint(reps))
|
|
var extra_bits uint32 = reps - (1 << run_length_prefix)
|
|
v[*out_size] = run_length_prefix + (extra_bits << 9)
|
|
(*out_size)++
|
|
break
|
|
} else {
|
|
var extra_bits uint32 = (1 << max_prefix) - 1
|
|
v[*out_size] = max_prefix + (extra_bits << 9)
|
|
reps -= (2 << max_prefix) - 1
|
|
(*out_size)++
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
const symbolBits = 9
|
|
|
|
var encodeContextMap_kSymbolMask uint32 = (1 << symbolBits) - 1
|
|
|
|
func encodeContextMap(context_map []uint32, context_map_size uint, num_clusters uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
var i uint
|
|
var rle_symbols []uint32
|
|
var max_run_length_prefix uint32 = 6
|
|
var num_rle_symbols uint = 0
|
|
var histogram [maxContextMapSymbols]uint32
|
|
var depths [maxContextMapSymbols]byte
|
|
var bits [maxContextMapSymbols]uint16
|
|
|
|
storeVarLenUint8(num_clusters-1, storage_ix, storage)
|
|
|
|
if num_clusters == 1 {
|
|
return
|
|
}
|
|
|
|
rle_symbols = make([]uint32, context_map_size)
|
|
moveToFrontTransform(context_map, context_map_size, rle_symbols)
|
|
runLengthCodeZeros(context_map_size, rle_symbols, &num_rle_symbols, &max_run_length_prefix)
|
|
histogram = [maxContextMapSymbols]uint32{}
|
|
for i = 0; i < num_rle_symbols; i++ {
|
|
histogram[rle_symbols[i]&encodeContextMap_kSymbolMask]++
|
|
}
|
|
{
|
|
var use_rle bool = (max_run_length_prefix > 0)
|
|
writeSingleBit(use_rle, storage_ix, storage)
|
|
if use_rle {
|
|
writeBits(4, uint64(max_run_length_prefix)-1, storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
buildAndStoreHuffmanTree(histogram[:], uint(uint32(num_clusters)+max_run_length_prefix), uint(uint32(num_clusters)+max_run_length_prefix), tree, depths[:], bits[:], storage_ix, storage)
|
|
for i = 0; i < num_rle_symbols; i++ {
|
|
var rle_symbol uint32 = rle_symbols[i] & encodeContextMap_kSymbolMask
|
|
var extra_bits_val uint32 = rle_symbols[i] >> symbolBits
|
|
writeBits(uint(depths[rle_symbol]), uint64(bits[rle_symbol]), storage_ix, storage)
|
|
if rle_symbol > 0 && rle_symbol <= max_run_length_prefix {
|
|
writeBits(uint(rle_symbol), uint64(extra_bits_val), storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
writeBits(1, 1, storage_ix, storage) /* use move-to-front */
|
|
rle_symbols = nil
|
|
}
|
|
|
|
/* Stores the block switch command with index block_ix to the bit stream. */
|
|
func storeBlockSwitch(code *blockSplitCode, block_len uint32, block_type byte, is_first_block bool, storage_ix *uint, storage []byte) {
|
|
var typecode uint = nextBlockTypeCode(&code.type_code_calculator, block_type)
|
|
var lencode uint
|
|
var len_nextra uint32
|
|
var len_extra uint32
|
|
if !is_first_block {
|
|
writeBits(uint(code.type_depths[typecode]), uint64(code.type_bits[typecode]), storage_ix, storage)
|
|
}
|
|
|
|
getBlockLengthPrefixCode(block_len, &lencode, &len_nextra, &len_extra)
|
|
|
|
writeBits(uint(code.length_depths[lencode]), uint64(code.length_bits[lencode]), storage_ix, storage)
|
|
writeBits(uint(len_nextra), uint64(len_extra), storage_ix, storage)
|
|
}
|
|
|
|
/* Builds a BlockSplitCode data structure from the block split given by the
|
|
vector of block types and block lengths and stores it to the bit stream. */
|
|
func buildAndStoreBlockSplitCode(types []byte, lengths []uint32, num_blocks uint, num_types uint, tree []huffmanTree, code *blockSplitCode, storage_ix *uint, storage []byte) {
|
|
var type_histo [maxBlockTypeSymbols]uint32
|
|
var length_histo [numBlockLenSymbols]uint32
|
|
var i uint
|
|
var type_code_calculator blockTypeCodeCalculator
|
|
for i := 0; i < int(num_types+2); i++ {
|
|
type_histo[i] = 0
|
|
}
|
|
length_histo = [numBlockLenSymbols]uint32{}
|
|
initBlockTypeCodeCalculator(&type_code_calculator)
|
|
for i = 0; i < num_blocks; i++ {
|
|
var type_code uint = nextBlockTypeCode(&type_code_calculator, types[i])
|
|
if i != 0 {
|
|
type_histo[type_code]++
|
|
}
|
|
length_histo[blockLengthPrefixCode(lengths[i])]++
|
|
}
|
|
|
|
storeVarLenUint8(num_types-1, storage_ix, storage)
|
|
if num_types > 1 { /* TODO: else? could StoreBlockSwitch occur? */
|
|
buildAndStoreHuffmanTree(type_histo[0:], num_types+2, num_types+2, tree, code.type_depths[0:], code.type_bits[0:], storage_ix, storage)
|
|
buildAndStoreHuffmanTree(length_histo[0:], numBlockLenSymbols, numBlockLenSymbols, tree, code.length_depths[0:], code.length_bits[0:], storage_ix, storage)
|
|
storeBlockSwitch(code, lengths[0], types[0], true, storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
/* Stores a context map where the histogram type is always the block type. */
|
|
func storeTrivialContextMap(num_types uint, context_bits uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
storeVarLenUint8(num_types-1, storage_ix, storage)
|
|
if num_types > 1 {
|
|
var repeat_code uint = context_bits - 1
|
|
var repeat_bits uint = (1 << repeat_code) - 1
|
|
var alphabet_size uint = num_types + repeat_code
|
|
var histogram [maxContextMapSymbols]uint32
|
|
var depths [maxContextMapSymbols]byte
|
|
var bits [maxContextMapSymbols]uint16
|
|
var i uint
|
|
for i := 0; i < int(alphabet_size); i++ {
|
|
histogram[i] = 0
|
|
}
|
|
|
|
/* Write RLEMAX. */
|
|
writeBits(1, 1, storage_ix, storage)
|
|
|
|
writeBits(4, uint64(repeat_code)-1, storage_ix, storage)
|
|
histogram[repeat_code] = uint32(num_types)
|
|
histogram[0] = 1
|
|
for i = context_bits; i < alphabet_size; i++ {
|
|
histogram[i] = 1
|
|
}
|
|
|
|
buildAndStoreHuffmanTree(histogram[:], alphabet_size, alphabet_size, tree, depths[:], bits[:], storage_ix, storage)
|
|
for i = 0; i < num_types; i++ {
|
|
var tmp uint
|
|
if i == 0 {
|
|
tmp = 0
|
|
} else {
|
|
tmp = i + context_bits - 1
|
|
}
|
|
var code uint = tmp
|
|
writeBits(uint(depths[code]), uint64(bits[code]), storage_ix, storage)
|
|
writeBits(uint(depths[repeat_code]), uint64(bits[repeat_code]), storage_ix, storage)
|
|
writeBits(repeat_code, uint64(repeat_bits), storage_ix, storage)
|
|
}
|
|
|
|
/* Write IMTF (inverse-move-to-front) bit. */
|
|
writeBits(1, 1, storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
/* Manages the encoding of one block category (literal, command or distance). */
|
|
type blockEncoder struct {
|
|
histogram_length_ uint
|
|
num_block_types_ uint
|
|
block_types_ []byte
|
|
block_lengths_ []uint32
|
|
num_blocks_ uint
|
|
block_split_code_ blockSplitCode
|
|
block_ix_ uint
|
|
block_len_ uint
|
|
entropy_ix_ uint
|
|
depths_ []byte
|
|
bits_ []uint16
|
|
}
|
|
|
|
var blockEncoderPool sync.Pool
|
|
|
|
func getBlockEncoder(histogram_length uint, num_block_types uint, block_types []byte, block_lengths []uint32, num_blocks uint) *blockEncoder {
|
|
self, _ := blockEncoderPool.Get().(*blockEncoder)
|
|
|
|
if self != nil {
|
|
self.block_ix_ = 0
|
|
self.entropy_ix_ = 0
|
|
self.depths_ = self.depths_[:0]
|
|
self.bits_ = self.bits_[:0]
|
|
} else {
|
|
self = &blockEncoder{}
|
|
}
|
|
|
|
self.histogram_length_ = histogram_length
|
|
self.num_block_types_ = num_block_types
|
|
self.block_types_ = block_types
|
|
self.block_lengths_ = block_lengths
|
|
self.num_blocks_ = num_blocks
|
|
initBlockTypeCodeCalculator(&self.block_split_code_.type_code_calculator)
|
|
if num_blocks == 0 {
|
|
self.block_len_ = 0
|
|
} else {
|
|
self.block_len_ = uint(block_lengths[0])
|
|
}
|
|
|
|
return self
|
|
}
|
|
|
|
func cleanupBlockEncoder(self *blockEncoder) {
|
|
blockEncoderPool.Put(self)
|
|
}
|
|
|
|
/* Creates entropy codes of block lengths and block types and stores them
|
|
to the bit stream. */
|
|
func buildAndStoreBlockSwitchEntropyCodes(self *blockEncoder, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
buildAndStoreBlockSplitCode(self.block_types_, self.block_lengths_, self.num_blocks_, self.num_block_types_, tree, &self.block_split_code_, storage_ix, storage)
|
|
}
|
|
|
|
/* Stores the next symbol with the entropy code of the current block type.
|
|
Updates the block type and block length at block boundaries. */
|
|
func storeSymbol(self *blockEncoder, symbol uint, storage_ix *uint, storage []byte) {
|
|
if self.block_len_ == 0 {
|
|
self.block_ix_++
|
|
var block_ix uint = self.block_ix_
|
|
var block_len uint32 = self.block_lengths_[block_ix]
|
|
var block_type byte = self.block_types_[block_ix]
|
|
self.block_len_ = uint(block_len)
|
|
self.entropy_ix_ = uint(block_type) * self.histogram_length_
|
|
storeBlockSwitch(&self.block_split_code_, block_len, block_type, false, storage_ix, storage)
|
|
}
|
|
|
|
self.block_len_--
|
|
{
|
|
var ix uint = self.entropy_ix_ + symbol
|
|
writeBits(uint(self.depths_[ix]), uint64(self.bits_[ix]), storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
/* Stores the next symbol with the entropy code of the current block type and
|
|
context value.
|
|
Updates the block type and block length at block boundaries. */
|
|
func storeSymbolWithContext(self *blockEncoder, symbol uint, context uint, context_map []uint32, storage_ix *uint, storage []byte, context_bits uint) {
|
|
if self.block_len_ == 0 {
|
|
self.block_ix_++
|
|
var block_ix uint = self.block_ix_
|
|
var block_len uint32 = self.block_lengths_[block_ix]
|
|
var block_type byte = self.block_types_[block_ix]
|
|
self.block_len_ = uint(block_len)
|
|
self.entropy_ix_ = uint(block_type) << context_bits
|
|
storeBlockSwitch(&self.block_split_code_, block_len, block_type, false, storage_ix, storage)
|
|
}
|
|
|
|
self.block_len_--
|
|
{
|
|
var histo_ix uint = uint(context_map[self.entropy_ix_+context])
|
|
var ix uint = histo_ix*self.histogram_length_ + symbol
|
|
writeBits(uint(self.depths_[ix]), uint64(self.bits_[ix]), storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
func buildAndStoreEntropyCodesLiteral(self *blockEncoder, histograms []histogramLiteral, histograms_size uint, alphabet_size uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
var table_size uint = histograms_size * self.histogram_length_
|
|
if cap(self.depths_) < int(table_size) {
|
|
self.depths_ = make([]byte, table_size)
|
|
} else {
|
|
self.depths_ = self.depths_[:table_size]
|
|
}
|
|
if cap(self.bits_) < int(table_size) {
|
|
self.bits_ = make([]uint16, table_size)
|
|
} else {
|
|
self.bits_ = self.bits_[:table_size]
|
|
}
|
|
{
|
|
var i uint
|
|
for i = 0; i < histograms_size; i++ {
|
|
var ix uint = i * self.histogram_length_
|
|
buildAndStoreHuffmanTree(histograms[i].data_[0:], self.histogram_length_, alphabet_size, tree, self.depths_[ix:], self.bits_[ix:], storage_ix, storage)
|
|
}
|
|
}
|
|
}
|
|
|
|
func buildAndStoreEntropyCodesCommand(self *blockEncoder, histograms []histogramCommand, histograms_size uint, alphabet_size uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
var table_size uint = histograms_size * self.histogram_length_
|
|
if cap(self.depths_) < int(table_size) {
|
|
self.depths_ = make([]byte, table_size)
|
|
} else {
|
|
self.depths_ = self.depths_[:table_size]
|
|
}
|
|
if cap(self.bits_) < int(table_size) {
|
|
self.bits_ = make([]uint16, table_size)
|
|
} else {
|
|
self.bits_ = self.bits_[:table_size]
|
|
}
|
|
{
|
|
var i uint
|
|
for i = 0; i < histograms_size; i++ {
|
|
var ix uint = i * self.histogram_length_
|
|
buildAndStoreHuffmanTree(histograms[i].data_[0:], self.histogram_length_, alphabet_size, tree, self.depths_[ix:], self.bits_[ix:], storage_ix, storage)
|
|
}
|
|
}
|
|
}
|
|
|
|
func buildAndStoreEntropyCodesDistance(self *blockEncoder, histograms []histogramDistance, histograms_size uint, alphabet_size uint, tree []huffmanTree, storage_ix *uint, storage []byte) {
|
|
var table_size uint = histograms_size * self.histogram_length_
|
|
if cap(self.depths_) < int(table_size) {
|
|
self.depths_ = make([]byte, table_size)
|
|
} else {
|
|
self.depths_ = self.depths_[:table_size]
|
|
}
|
|
if cap(self.bits_) < int(table_size) {
|
|
self.bits_ = make([]uint16, table_size)
|
|
} else {
|
|
self.bits_ = self.bits_[:table_size]
|
|
}
|
|
{
|
|
var i uint
|
|
for i = 0; i < histograms_size; i++ {
|
|
var ix uint = i * self.histogram_length_
|
|
buildAndStoreHuffmanTree(histograms[i].data_[0:], self.histogram_length_, alphabet_size, tree, self.depths_[ix:], self.bits_[ix:], storage_ix, storage)
|
|
}
|
|
}
|
|
}
|
|
|
|
func jumpToByteBoundary(storage_ix *uint, storage []byte) {
|
|
*storage_ix = (*storage_ix + 7) &^ 7
|
|
storage[*storage_ix>>3] = 0
|
|
}
|
|
|
|
func storeMetaBlock(input []byte, start_pos uint, length uint, mask uint, prev_byte byte, prev_byte2 byte, is_last bool, params *encoderParams, literal_context_mode int, commands []command, mb *metaBlockSplit, storage_ix *uint, storage []byte) {
|
|
var pos uint = start_pos
|
|
var i uint
|
|
var num_distance_symbols uint32 = params.dist.alphabet_size
|
|
var num_effective_distance_symbols uint32 = num_distance_symbols
|
|
var tree []huffmanTree
|
|
var literal_context_lut contextLUT = getContextLUT(literal_context_mode)
|
|
var dist *distanceParams = ¶ms.dist
|
|
if params.large_window && num_effective_distance_symbols > numHistogramDistanceSymbols {
|
|
num_effective_distance_symbols = numHistogramDistanceSymbols
|
|
}
|
|
|
|
storeCompressedMetaBlockHeader(is_last, length, storage_ix, storage)
|
|
|
|
tree = make([]huffmanTree, maxHuffmanTreeSize)
|
|
literal_enc := getBlockEncoder(numLiteralSymbols, mb.literal_split.num_types, mb.literal_split.types, mb.literal_split.lengths, mb.literal_split.num_blocks)
|
|
command_enc := getBlockEncoder(numCommandSymbols, mb.command_split.num_types, mb.command_split.types, mb.command_split.lengths, mb.command_split.num_blocks)
|
|
distance_enc := getBlockEncoder(uint(num_effective_distance_symbols), mb.distance_split.num_types, mb.distance_split.types, mb.distance_split.lengths, mb.distance_split.num_blocks)
|
|
|
|
buildAndStoreBlockSwitchEntropyCodes(literal_enc, tree, storage_ix, storage)
|
|
buildAndStoreBlockSwitchEntropyCodes(command_enc, tree, storage_ix, storage)
|
|
buildAndStoreBlockSwitchEntropyCodes(distance_enc, tree, storage_ix, storage)
|
|
|
|
writeBits(2, uint64(dist.distance_postfix_bits), storage_ix, storage)
|
|
writeBits(4, uint64(dist.num_direct_distance_codes)>>dist.distance_postfix_bits, storage_ix, storage)
|
|
for i = 0; i < mb.literal_split.num_types; i++ {
|
|
writeBits(2, uint64(literal_context_mode), storage_ix, storage)
|
|
}
|
|
|
|
if mb.literal_context_map_size == 0 {
|
|
storeTrivialContextMap(mb.literal_histograms_size, literalContextBits, tree, storage_ix, storage)
|
|
} else {
|
|
encodeContextMap(mb.literal_context_map, mb.literal_context_map_size, mb.literal_histograms_size, tree, storage_ix, storage)
|
|
}
|
|
|
|
if mb.distance_context_map_size == 0 {
|
|
storeTrivialContextMap(mb.distance_histograms_size, distanceContextBits, tree, storage_ix, storage)
|
|
} else {
|
|
encodeContextMap(mb.distance_context_map, mb.distance_context_map_size, mb.distance_histograms_size, tree, storage_ix, storage)
|
|
}
|
|
|
|
buildAndStoreEntropyCodesLiteral(literal_enc, mb.literal_histograms, mb.literal_histograms_size, numLiteralSymbols, tree, storage_ix, storage)
|
|
buildAndStoreEntropyCodesCommand(command_enc, mb.command_histograms, mb.command_histograms_size, numCommandSymbols, tree, storage_ix, storage)
|
|
buildAndStoreEntropyCodesDistance(distance_enc, mb.distance_histograms, mb.distance_histograms_size, uint(num_distance_symbols), tree, storage_ix, storage)
|
|
tree = nil
|
|
|
|
for _, cmd := range commands {
|
|
var cmd_code uint = uint(cmd.cmd_prefix_)
|
|
storeSymbol(command_enc, cmd_code, storage_ix, storage)
|
|
storeCommandExtra(&cmd, storage_ix, storage)
|
|
if mb.literal_context_map_size == 0 {
|
|
var j uint
|
|
for j = uint(cmd.insert_len_); j != 0; j-- {
|
|
storeSymbol(literal_enc, uint(input[pos&mask]), storage_ix, storage)
|
|
pos++
|
|
}
|
|
} else {
|
|
var j uint
|
|
for j = uint(cmd.insert_len_); j != 0; j-- {
|
|
var context uint = uint(getContext(prev_byte, prev_byte2, literal_context_lut))
|
|
var literal byte = input[pos&mask]
|
|
storeSymbolWithContext(literal_enc, uint(literal), context, mb.literal_context_map, storage_ix, storage, literalContextBits)
|
|
prev_byte2 = prev_byte
|
|
prev_byte = literal
|
|
pos++
|
|
}
|
|
}
|
|
|
|
pos += uint(commandCopyLen(&cmd))
|
|
if commandCopyLen(&cmd) != 0 {
|
|
prev_byte2 = input[(pos-2)&mask]
|
|
prev_byte = input[(pos-1)&mask]
|
|
if cmd.cmd_prefix_ >= 128 {
|
|
var dist_code uint = uint(cmd.dist_prefix_) & 0x3FF
|
|
var distnumextra uint32 = uint32(cmd.dist_prefix_) >> 10
|
|
var distextra uint64 = uint64(cmd.dist_extra_)
|
|
if mb.distance_context_map_size == 0 {
|
|
storeSymbol(distance_enc, dist_code, storage_ix, storage)
|
|
} else {
|
|
var context uint = uint(commandDistanceContext(&cmd))
|
|
storeSymbolWithContext(distance_enc, dist_code, context, mb.distance_context_map, storage_ix, storage, distanceContextBits)
|
|
}
|
|
|
|
writeBits(uint(distnumextra), distextra, storage_ix, storage)
|
|
}
|
|
}
|
|
}
|
|
|
|
cleanupBlockEncoder(distance_enc)
|
|
cleanupBlockEncoder(command_enc)
|
|
cleanupBlockEncoder(literal_enc)
|
|
if is_last {
|
|
jumpToByteBoundary(storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
func buildHistograms(input []byte, start_pos uint, mask uint, commands []command, lit_histo *histogramLiteral, cmd_histo *histogramCommand, dist_histo *histogramDistance) {
|
|
var pos uint = start_pos
|
|
for _, cmd := range commands {
|
|
var j uint
|
|
histogramAddCommand(cmd_histo, uint(cmd.cmd_prefix_))
|
|
for j = uint(cmd.insert_len_); j != 0; j-- {
|
|
histogramAddLiteral(lit_histo, uint(input[pos&mask]))
|
|
pos++
|
|
}
|
|
|
|
pos += uint(commandCopyLen(&cmd))
|
|
if commandCopyLen(&cmd) != 0 && cmd.cmd_prefix_ >= 128 {
|
|
histogramAddDistance(dist_histo, uint(cmd.dist_prefix_)&0x3FF)
|
|
}
|
|
}
|
|
}
|
|
|
|
func storeDataWithHuffmanCodes(input []byte, start_pos uint, mask uint, commands []command, lit_depth []byte, lit_bits []uint16, cmd_depth []byte, cmd_bits []uint16, dist_depth []byte, dist_bits []uint16, storage_ix *uint, storage []byte) {
|
|
var pos uint = start_pos
|
|
for _, cmd := range commands {
|
|
var cmd_code uint = uint(cmd.cmd_prefix_)
|
|
var j uint
|
|
writeBits(uint(cmd_depth[cmd_code]), uint64(cmd_bits[cmd_code]), storage_ix, storage)
|
|
storeCommandExtra(&cmd, storage_ix, storage)
|
|
for j = uint(cmd.insert_len_); j != 0; j-- {
|
|
var literal byte = input[pos&mask]
|
|
writeBits(uint(lit_depth[literal]), uint64(lit_bits[literal]), storage_ix, storage)
|
|
pos++
|
|
}
|
|
|
|
pos += uint(commandCopyLen(&cmd))
|
|
if commandCopyLen(&cmd) != 0 && cmd.cmd_prefix_ >= 128 {
|
|
var dist_code uint = uint(cmd.dist_prefix_) & 0x3FF
|
|
var distnumextra uint32 = uint32(cmd.dist_prefix_) >> 10
|
|
var distextra uint32 = cmd.dist_extra_
|
|
writeBits(uint(dist_depth[dist_code]), uint64(dist_bits[dist_code]), storage_ix, storage)
|
|
writeBits(uint(distnumextra), uint64(distextra), storage_ix, storage)
|
|
}
|
|
}
|
|
}
|
|
|
|
func storeMetaBlockTrivial(input []byte, start_pos uint, length uint, mask uint, is_last bool, params *encoderParams, commands []command, storage_ix *uint, storage []byte) {
|
|
var lit_histo histogramLiteral
|
|
var cmd_histo histogramCommand
|
|
var dist_histo histogramDistance
|
|
var lit_depth [numLiteralSymbols]byte
|
|
var lit_bits [numLiteralSymbols]uint16
|
|
var cmd_depth [numCommandSymbols]byte
|
|
var cmd_bits [numCommandSymbols]uint16
|
|
var dist_depth [maxSimpleDistanceAlphabetSize]byte
|
|
var dist_bits [maxSimpleDistanceAlphabetSize]uint16
|
|
var tree []huffmanTree
|
|
var num_distance_symbols uint32 = params.dist.alphabet_size
|
|
|
|
storeCompressedMetaBlockHeader(is_last, length, storage_ix, storage)
|
|
|
|
histogramClearLiteral(&lit_histo)
|
|
histogramClearCommand(&cmd_histo)
|
|
histogramClearDistance(&dist_histo)
|
|
|
|
buildHistograms(input, start_pos, mask, commands, &lit_histo, &cmd_histo, &dist_histo)
|
|
|
|
writeBits(13, 0, storage_ix, storage)
|
|
|
|
tree = make([]huffmanTree, maxHuffmanTreeSize)
|
|
buildAndStoreHuffmanTree(lit_histo.data_[:], numLiteralSymbols, numLiteralSymbols, tree, lit_depth[:], lit_bits[:], storage_ix, storage)
|
|
buildAndStoreHuffmanTree(cmd_histo.data_[:], numCommandSymbols, numCommandSymbols, tree, cmd_depth[:], cmd_bits[:], storage_ix, storage)
|
|
buildAndStoreHuffmanTree(dist_histo.data_[:], maxSimpleDistanceAlphabetSize, uint(num_distance_symbols), tree, dist_depth[:], dist_bits[:], storage_ix, storage)
|
|
tree = nil
|
|
storeDataWithHuffmanCodes(input, start_pos, mask, commands, lit_depth[:], lit_bits[:], cmd_depth[:], cmd_bits[:], dist_depth[:], dist_bits[:], storage_ix, storage)
|
|
if is_last {
|
|
jumpToByteBoundary(storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
func storeMetaBlockFast(input []byte, start_pos uint, length uint, mask uint, is_last bool, params *encoderParams, commands []command, storage_ix *uint, storage []byte) {
|
|
var num_distance_symbols uint32 = params.dist.alphabet_size
|
|
var distance_alphabet_bits uint32 = log2FloorNonZero(uint(num_distance_symbols-1)) + 1
|
|
|
|
storeCompressedMetaBlockHeader(is_last, length, storage_ix, storage)
|
|
|
|
writeBits(13, 0, storage_ix, storage)
|
|
|
|
if len(commands) <= 128 {
|
|
var histogram = [numLiteralSymbols]uint32{0}
|
|
var pos uint = start_pos
|
|
var num_literals uint = 0
|
|
var lit_depth [numLiteralSymbols]byte
|
|
var lit_bits [numLiteralSymbols]uint16
|
|
for _, cmd := range commands {
|
|
var j uint
|
|
for j = uint(cmd.insert_len_); j != 0; j-- {
|
|
histogram[input[pos&mask]]++
|
|
pos++
|
|
}
|
|
|
|
num_literals += uint(cmd.insert_len_)
|
|
pos += uint(commandCopyLen(&cmd))
|
|
}
|
|
|
|
buildAndStoreHuffmanTreeFast(histogram[:], num_literals, /* max_bits = */
|
|
8, lit_depth[:], lit_bits[:], storage_ix, storage)
|
|
|
|
storeStaticCommandHuffmanTree(storage_ix, storage)
|
|
storeStaticDistanceHuffmanTree(storage_ix, storage)
|
|
storeDataWithHuffmanCodes(input, start_pos, mask, commands, lit_depth[:], lit_bits[:], kStaticCommandCodeDepth[:], kStaticCommandCodeBits[:], kStaticDistanceCodeDepth[:], kStaticDistanceCodeBits[:], storage_ix, storage)
|
|
} else {
|
|
var lit_histo histogramLiteral
|
|
var cmd_histo histogramCommand
|
|
var dist_histo histogramDistance
|
|
var lit_depth [numLiteralSymbols]byte
|
|
var lit_bits [numLiteralSymbols]uint16
|
|
var cmd_depth [numCommandSymbols]byte
|
|
var cmd_bits [numCommandSymbols]uint16
|
|
var dist_depth [maxSimpleDistanceAlphabetSize]byte
|
|
var dist_bits [maxSimpleDistanceAlphabetSize]uint16
|
|
histogramClearLiteral(&lit_histo)
|
|
histogramClearCommand(&cmd_histo)
|
|
histogramClearDistance(&dist_histo)
|
|
buildHistograms(input, start_pos, mask, commands, &lit_histo, &cmd_histo, &dist_histo)
|
|
buildAndStoreHuffmanTreeFast(lit_histo.data_[:], lit_histo.total_count_, /* max_bits = */
|
|
8, lit_depth[:], lit_bits[:], storage_ix, storage)
|
|
|
|
buildAndStoreHuffmanTreeFast(cmd_histo.data_[:], cmd_histo.total_count_, /* max_bits = */
|
|
10, cmd_depth[:], cmd_bits[:], storage_ix, storage)
|
|
|
|
buildAndStoreHuffmanTreeFast(dist_histo.data_[:], dist_histo.total_count_, /* max_bits = */
|
|
uint(distance_alphabet_bits), dist_depth[:], dist_bits[:], storage_ix, storage)
|
|
|
|
storeDataWithHuffmanCodes(input, start_pos, mask, commands, lit_depth[:], lit_bits[:], cmd_depth[:], cmd_bits[:], dist_depth[:], dist_bits[:], storage_ix, storage)
|
|
}
|
|
|
|
if is_last {
|
|
jumpToByteBoundary(storage_ix, storage)
|
|
}
|
|
}
|
|
|
|
/* This is for storing uncompressed blocks (simple raw storage of
|
|
bytes-as-bytes). */
|
|
func storeUncompressedMetaBlock(is_final_block bool, input []byte, position uint, mask uint, len uint, storage_ix *uint, storage []byte) {
|
|
var masked_pos uint = position & mask
|
|
storeUncompressedMetaBlockHeader(uint(len), storage_ix, storage)
|
|
jumpToByteBoundary(storage_ix, storage)
|
|
|
|
if masked_pos+len > mask+1 {
|
|
var len1 uint = mask + 1 - masked_pos
|
|
copy(storage[*storage_ix>>3:], input[masked_pos:][:len1])
|
|
*storage_ix += len1 << 3
|
|
len -= len1
|
|
masked_pos = 0
|
|
}
|
|
|
|
copy(storage[*storage_ix>>3:], input[masked_pos:][:len])
|
|
*storage_ix += uint(len << 3)
|
|
|
|
/* We need to clear the next 4 bytes to continue to be
|
|
compatible with BrotliWriteBits. */
|
|
writeBitsPrepareStorage(*storage_ix, storage)
|
|
|
|
/* Since the uncompressed block itself may not be the final block, add an
|
|
empty one after this. */
|
|
if is_final_block {
|
|
writeBits(1, 1, storage_ix, storage) /* islast */
|
|
writeBits(1, 1, storage_ix, storage) /* isempty */
|
|
jumpToByteBoundary(storage_ix, storage)
|
|
}
|
|
}
|