Package: github.com/andybalholm/brotli/flate

package flate Import Path github.com/andybalholm/brotli/flate (on go.dev) Dependency Relation imports 8 packages, and imported by one package

Involved Source Files gzip.go huffman_bit_writer.go huffman_code.go token.go writer.go

Package-Level Type Names (total 8, none are exported)

/* sort exporteds by: alphabet | popularity */

/* 8 unexporteds ... *//* 8 unexporteds: */

type byFreq ([]) Methods (total 4, in which 3 are exported) ( byFreq) Len() int ( byFreq) Less(i, j int) bool ( byFreq) Swap(i, j int) /* one unexported ... *//* one unexported: */ (*byFreq) sort(a []literalNode) Implements (at least one exported) byFreq : sort.Interface

type byLiteral ([]) Methods (total 4, in which 3 are exported) ( byLiteral) Len() int ( byLiteral) Less(i, j int) bool ( byLiteral) Swap(i, j int) /* one unexported ... *//* one unexported: */ (*byLiteral) sort(a []literalNode) Implements (at least one exported) byLiteral : sort.Interface

type gzipEncoder (struct) Fields (total 4, none are exported) /* 4 unexporteds ... *//* 4 unexporteds: */ crc uint32 f matchfinder.Encoder length uint32 wroteHeader bool Methods (total 2, both are exported) (*gzipEncoder) Encode(dst []byte, src []byte, matches []matchfinder.Match, lastBlock bool) []byte (*gzipEncoder) Reset() Implements (at least one exported) *gzipEncoder : github.com/andybalholm/brotli/matchfinder.Encoder

type hcode (struct) hcode is a huffman code with a bit code and bit length. Fields (total 2, neither is exported) /* 2 unexporteds ... *//* 2 unexporteds: */ code uint16 len uint16 Methods (only one, which is unexported) /* one unexported ... *//* one unexported: */ (*hcode) set(code uint16, length uint16) set sets the code and length of an hcode.

type huffmanBitWriter (struct) Fields (total 10, none are exported) /* 10 unexporteds ... *//* 10 unexporteds: */ bits uint64 Data waiting to be written is the low nbits of bits. codegen []uint8 codegenEncoding *huffmanEncoder codegenFreq [19]int32 dst []byte literalEncoding *huffmanEncoder literalFreq []int32 nbits uint offsetEncoding *huffmanEncoder offsetFreq []int32 Methods (total 16, in which 2 are exported) (*huffmanBitWriter) Encode(dst []byte, src []byte, matches []matchfinder.Match, lastBlock bool) []byte (*huffmanBitWriter) Reset() /* 14 unexporteds ... *//* 14 unexporteds: */ (*huffmanBitWriter) dynamicSize(litEnc, offEnc *huffmanEncoder, extraBits int) (size, numCodegens int) dynamicSize returns the size of dynamically encoded data in bits. (*huffmanBitWriter) fixedSize(extraBits int) int fixedSize returns the size of dynamically encoded data in bits. (*huffmanBitWriter) flush() (*huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int, litEnc, offEnc *huffmanEncoder) RFC 1951 3.2.7 specifies a special run-length encoding for specifying the literal and offset lengths arrays (which are concatenated into a single array). This method generates that run-length encoding. The result is written into the codegen array, and the frequencies of each code is written into the codegenFreq array. Codes 0-15 are single byte codes. Codes 16-18 are followed by additional information. Code badCode is an end marker numLiterals The number of literals in literalEncoding numOffsets The number of offsets in offsetEncoding litenc, offenc The literal and offset encoder to use (*huffmanBitWriter) makeStatistics(matches []matchfinder.Match, input []byte) (numLiterals, numOffsets int) makeStatistics indexes a slice of tokens, and updates literalFreq and offsetFreq, and generates literalEncoding and offsetEncoding. The number of literal and offset tokens is returned. (*huffmanBitWriter) storedSize(in []byte) (int, bool) storedSize calculates the stored size, including header. The function returns the size in bits and whether the block fits inside a single block. (*huffmanBitWriter) writeBits(b int32, nb uint) (*huffmanBitWriter) writeBlock(matches []matchfinder.Match, eof bool, input []byte) writeBlock will write a block of tokens with the smallest encoding. (*huffmanBitWriter) writeBytes(bytes []byte) (*huffmanBitWriter) writeCode(c hcode) (*huffmanBitWriter) writeDynamicHeader(numLiterals int, numOffsets int, numCodegens int, isEof bool) Write the header of a dynamic Huffman block to the output stream. numLiterals The number of literals specified in codegen numOffsets The number of offsets specified in codegen numCodegens The number of codegens used in codegen (*huffmanBitWriter) writeFixedHeader(isEof bool) (*huffmanBitWriter) writeStoredHeader(length int, isEof bool) (*huffmanBitWriter) writeTokens(matches []matchfinder.Match, input []byte, leCodes, oeCodes []hcode) writeTokens writes a slice of tokens to the output. codes for literal and offset encoding must be supplied. Implements (at least one exported) *huffmanBitWriter : github.com/andybalholm/brotli/matchfinder.Encoder

type huffmanEncoder (struct) Fields (total 5, none are exported) /* 5 unexporteds ... *//* 5 unexporteds: */ bitCount [17]int32 codes []hcode freqcache []literalNode lfs byFreq // stored to avoid repeated allocation in generate lns byLiteral // stored to avoid repeated allocation in generate Methods (total 4, none are exported) /* 4 unexporteds ... *//* 4 unexporteds: */ (*huffmanEncoder) assignEncodingAndSize(bitCount []int32, list []literalNode) Look at the leaves and assign them a bit count and an encoding as specified in RFC 1951 3.2.2 (*huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 Return the number of literals assigned to each bit size in the Huffman encoding This method is only called when list.length >= 3 The cases of 0, 1, and 2 literals are handled by special case code. list An array of the literals with non-zero frequencies and their associated frequencies. The array is in order of increasing frequency, and has as its last element a special element with frequency MaxInt32 maxBits The maximum number of bits that should be used to encode any literal. Must be less than 16. return An integer array in which array[i] indicates the number of literals that should be encoded in i bits. (*huffmanEncoder) bitLength(freq []int32) int (*huffmanEncoder) generate(freq []int32, maxBits int32) Update this Huffman Code object to be the minimum code for the specified frequency count. freq An array of frequencies, in which frequency[i] gives the frequency of literal i. maxBits The maximum number of bits to use for any literal. As Outputs Of (at least 3, none are exported) /* 3+ unexporteds ... *//* 3+ unexporteds: */ func generateFixedLiteralEncoding() *huffmanEncoder func generateFixedOffsetEncoding() *huffmanEncoder func newHuffmanEncoder(size int) *huffmanEncoder As Types Of (total 2, neither is exported) /* 2 unexporteds ... *//* 2 unexporteds: */ var fixedLiteralEncoding *huffmanEncoder var fixedOffsetEncoding *huffmanEncoder

type levelInfo (struct) A levelInfo describes the state of the constructed tree for a given depth. Fields (total 5, none are exported) /* 5 unexporteds ... *//* 5 unexporteds: */ lastFreq int32 The frequency of the last node at this level level int32 Our level. for better printing needed int32 The number of chains remaining to generate for this level before moving up to the next level nextCharFreq int32 The frequency of the next character to add to this level nextPairFreq int32 The frequency of the next pair (from level below) to add to this level. Only valid if the "needed" value of the next lower level is 0.

type literalNode (struct) Fields (total 2, neither is exported) /* 2 unexporteds ... *//* 2 unexporteds: */ freq int32 literal uint16 As Outputs Of (at least one unexported) /* at least one unexported ... *//* at least one unexported: */ func maxNode() literalNode

Package-Level Functions (total 13, in which 4 are exported)

func NewEncoder() matchfinder.Encoder

func NewGZIPEncoder() matchfinder.Encoder

func NewGZIPWriter(w io.Writer, level int) *matchfinder.Writer NewGZIPWriter returns a new matchfinder.Writer that compresses data at the given level, in gzip encoding. Levels 1–9 are available; levels outside this range will be replaced by the closest level available.

func NewWriter(w io.Writer, level int) *matchfinder.Writer NewWriter returns a new matchfinder.Writer that compresses data at the given level, in flate encoding. Levels 1–9 are available; levels outside this range will be replaced with the closest level available.

/* 9 unexporteds ... *//* 9 unexporteds: */

func appendUint32(dst []byte, n uint32) []byte

func generateFixedLiteralEncoding() *huffmanEncoder Generates a HuffmanCode corresponding to the fixed literal table

func generateFixedOffsetEncoding() *huffmanEncoder

func lengthCode(len int) uint32

func maxNode() literalNode

func newHuffmanEncoder(size int) *huffmanEncoder

func newWriter(w io.Writer, level int, e matchfinder.Encoder) *matchfinder.Writer

func offsetCode(off int) uint32 Returns the offset code corresponding to a specific offset

func reverseBits(number uint16, bitLength byte) uint16

Package-Level Variables (total 9, none are exported) /* 9 unexporteds ... *//* 9 unexporteds: */

var codegenOrder []uint32 The odd order in which the codegen code sizes are written.

var fixedLiteralEncoding *huffmanEncoder

var fixedOffsetEncoding *huffmanEncoder

var lengthBase []int The length indicated by length code X - LENGTH_CODES_START.

var lengthCodes [256]uint32 The length code for length X (MIN_MATCH_LENGTH <= X <= MAX_MATCH_LENGTH) is lengthCodes[length - MIN_MATCH_LENGTH]

var lengthExtraBits []int8 The number of extra bits needed by length code X - LENGTH_CODES_START.

var offsetBase []int

var offsetCodes [256]uint32

var offsetExtraBits []int8 offset code word extra bits.

Package-Level Constants (total 10, none are exported) /* 10 unexporteds ... *//* 10 unexporteds: */

const badCode = 255

const baseMatchLength = 3 // The smallest match length per the RFC section 3.2.5

const baseMatchOffset = 1 // The smallest match offset

const codegenCodeCount = 19 The number of codegen codes.

const endBlockMarker = 256 The special code used to mark the end of a block.

const lengthCodesStart = 257 The first length code.

const maxBitsLimit = 16

const maxNumLit = 286

const maxStoreBlockSize = 65535

const offsetCodeCount = 30 The largest offset code.