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* Dump: Use mholt/archive/v3 to support tar including many compressions Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Dump: Allow dump output to stdout Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Dump: Fixed bug present since #6677 where SessionConfig.Provider is never "file" Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Dump: never pack RepoRootPath, LFS.ContentPath and LogRootPath when they are below AppDataPath Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Dump: also dump LFS (fixes #10058) Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Dump: never dump CustomPath if CustomPath is a subdir of or equal to AppDataPath (fixes #10365) Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * Use log.Info instead of fmt.Fprintf Signed-off-by: Philipp Homann <homann.philipp@googlemail.com> * import ordering * make fmt Co-authored-by: zeripath <art27@cantab.net> Co-authored-by: techknowlogick <techknowlogick@gitea.io> Co-authored-by: Matti R <matti@mdranta.net>
1236 lines
31 KiB
Go
Vendored
1236 lines
31 KiB
Go
Vendored
/*
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* LZMA2 decoder
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*
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* Authors: Lasse Collin <lasse.collin@tukaani.org>
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* Igor Pavlov <http://7-zip.org/>
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*
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* Translation to Go: Michael Cross <https://github.com/xi2>
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*
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* This file has been put into the public domain.
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* You can do whatever you want with this file.
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*/
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package xz
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/* from linux/lib/xz/xz_lzma2.h ***************************************/
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/* Range coder constants */
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const (
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rcShiftBits = 8
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rcTopBits = 24
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rcTopValue = 1 << rcTopBits
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rcBitModelTotalBits = 11
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rcBitModelTotal = 1 << rcBitModelTotalBits
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rcMoveBits = 5
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)
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/*
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* Maximum number of position states. A position state is the lowest pb
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* number of bits of the current uncompressed offset. In some places there
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* are different sets of probabilities for different position states.
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*/
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const posStatesMax = 1 << 4
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/*
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* lzmaState is used to track which LZMA symbols have occurred most recently
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* and in which order. This information is used to predict the next symbol.
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*
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* Symbols:
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* - Literal: One 8-bit byte
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* - Match: Repeat a chunk of data at some distance
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* - Long repeat: Multi-byte match at a recently seen distance
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* - Short repeat: One-byte repeat at a recently seen distance
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*
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* The symbol names are in from STATE-oldest-older-previous. REP means
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* either short or long repeated match, and NONLIT means any non-literal.
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*/
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type lzmaState int
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const (
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stateLitLit lzmaState = iota
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stateMatchLitLit
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stateRepLitLit
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stateShortrepLitLit
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stateMatchLit
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stateRepList
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stateShortrepLit
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stateLitMatch
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stateLitLongrep
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stateLitShortrep
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stateNonlitMatch
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stateNonlitRep
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)
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/* Total number of states */
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const states = 12
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/* The lowest 7 states indicate that the previous state was a literal. */
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const litStates = 7
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/* Indicate that the latest symbol was a literal. */
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func lzmaStateLiteral(state *lzmaState) {
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switch {
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case *state <= stateShortrepLitLit:
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*state = stateLitLit
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case *state <= stateLitShortrep:
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*state -= 3
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default:
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*state -= 6
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}
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}
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/* Indicate that the latest symbol was a match. */
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func lzmaStateMatch(state *lzmaState) {
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if *state < litStates {
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*state = stateLitMatch
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} else {
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*state = stateNonlitMatch
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}
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}
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/* Indicate that the latest state was a long repeated match. */
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func lzmaStateLongRep(state *lzmaState) {
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if *state < litStates {
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*state = stateLitLongrep
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} else {
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*state = stateNonlitRep
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}
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}
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/* Indicate that the latest symbol was a short match. */
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func lzmaStateShortRep(state *lzmaState) {
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if *state < litStates {
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*state = stateLitShortrep
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} else {
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*state = stateNonlitRep
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}
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}
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/* Test if the previous symbol was a literal. */
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func lzmaStateIsLiteral(state lzmaState) bool {
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return state < litStates
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}
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/* Each literal coder is divided in three sections:
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* - 0x001-0x0FF: Without match byte
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* - 0x101-0x1FF: With match byte; match bit is 0
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* - 0x201-0x2FF: With match byte; match bit is 1
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*
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* Match byte is used when the previous LZMA symbol was something else than
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* a literal (that is, it was some kind of match).
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*/
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const literalCoderSize = 0x300
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/* Maximum number of literal coders */
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const literalCodersMax = 1 << 4
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/* Minimum length of a match is two bytes. */
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const matchLenMin = 2
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/* Match length is encoded with 4, 5, or 10 bits.
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*
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* Length Bits
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* 2-9 4 = Choice=0 + 3 bits
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* 10-17 5 = Choice=1 + Choice2=0 + 3 bits
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* 18-273 10 = Choice=1 + Choice2=1 + 8 bits
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*/
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const (
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lenLowBits = 3
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lenLowSymbols = 1 << lenLowBits
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lenMidBits = 3
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lenMidSymbols = 1 << lenMidBits
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lenHighBits = 8
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lenHighSymbols = 1 << lenHighBits
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)
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/*
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* Different sets of probabilities are used for match distances that have
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* very short match length: Lengths of 2, 3, and 4 bytes have a separate
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* set of probabilities for each length. The matches with longer length
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* use a shared set of probabilities.
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*/
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const distStates = 4
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/*
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* Get the index of the appropriate probability array for decoding
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* the distance slot.
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*/
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func lzmaGetDistState(len uint32) uint32 {
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if len < distStates+matchLenMin {
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return len - matchLenMin
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} else {
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return distStates - 1
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}
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}
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/*
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* The highest two bits of a 32-bit match distance are encoded using six bits.
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* This six-bit value is called a distance slot. This way encoding a 32-bit
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* value takes 6-36 bits, larger values taking more bits.
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*/
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const (
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distSlotBits = 6
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distSlots = 1 << distSlotBits
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)
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/* Match distances up to 127 are fully encoded using probabilities. Since
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* the highest two bits (distance slot) are always encoded using six bits,
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* the distances 0-3 don't need any additional bits to encode, since the
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* distance slot itself is the same as the actual distance. distModelStart
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* indicates the first distance slot where at least one additional bit is
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* needed.
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*/
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const distModelStart = 4
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/*
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* Match distances greater than 127 are encoded in three pieces:
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* - distance slot: the highest two bits
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* - direct bits: 2-26 bits below the highest two bits
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* - alignment bits: four lowest bits
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*
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* Direct bits don't use any probabilities.
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*
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* The distance slot value of 14 is for distances 128-191.
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*/
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const distModelEnd = 14
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/* Distance slots that indicate a distance <= 127. */
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const (
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fullDistancesBits = distModelEnd / 2
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fullDistances = 1 << fullDistancesBits
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)
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/*
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* For match distances greater than 127, only the highest two bits and the
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* lowest four bits (alignment) is encoded using probabilities.
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*/
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const (
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alignBits = 4
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alignSize = 1 << alignBits
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)
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/* from linux/lib/xz/xz_dec_lzma2.c ***********************************/
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/*
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* Range decoder initialization eats the first five bytes of each LZMA chunk.
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*/
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const rcInitBytes = 5
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/*
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* Minimum number of usable input buffer to safely decode one LZMA symbol.
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* The worst case is that we decode 22 bits using probabilities and 26
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* direct bits. This may decode at maximum of 20 bytes of input. However,
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* lzmaMain does an extra normalization before returning, thus we
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* need to put 21 here.
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*/
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const lzmaInRequired = 21
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/*
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* Dictionary (history buffer)
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*
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* These are always true:
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* start <= pos <= full <= end
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* pos <= limit <= end
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* end == size
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* size <= sizeMax
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* len(buf) <= size
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*/
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type dictionary struct {
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/* The history buffer */
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buf []byte
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/* Old position in buf (before decoding more data) */
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start uint32
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/* Position in buf */
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pos uint32
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/*
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* How full dictionary is. This is used to detect corrupt input that
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* would read beyond the beginning of the uncompressed stream.
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*/
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full uint32
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/* Write limit; we don't write to buf[limit] or later bytes. */
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limit uint32
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/*
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* End of the dictionary buffer. This is the same as the
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* dictionary size.
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*/
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end uint32
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/*
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* Size of the dictionary as specified in Block Header. This is used
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* together with "full" to detect corrupt input that would make us
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* read beyond the beginning of the uncompressed stream.
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*/
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size uint32
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/* Maximum allowed dictionary size. */
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sizeMax uint32
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}
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/* Range decoder */
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type rcDec struct {
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rnge uint32
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code uint32
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/*
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* Number of initializing bytes remaining to be read
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* by rcReadInit.
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*/
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initBytesLeft uint32
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/*
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* Buffer from which we read our input. It can be either
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* temp.buf or the caller-provided input buffer.
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*/
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in []byte
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inPos int
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inLimit int
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}
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/* Probabilities for a length decoder. */
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type lzmaLenDec struct {
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/* Probability of match length being at least 10 */
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choice uint16
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/* Probability of match length being at least 18 */
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choice2 uint16
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/* Probabilities for match lengths 2-9 */
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low [posStatesMax][lenLowSymbols]uint16
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/* Probabilities for match lengths 10-17 */
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mid [posStatesMax][lenMidSymbols]uint16
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/* Probabilities for match lengths 18-273 */
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high [lenHighSymbols]uint16
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}
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type lzmaDec struct {
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/* Distances of latest four matches */
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rep0 uint32
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rep1 uint32
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rep2 uint32
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rep3 uint32
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/* Types of the most recently seen LZMA symbols */
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state lzmaState
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/*
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* Length of a match. This is updated so that dictRepeat can
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* be called again to finish repeating the whole match.
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*/
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len uint32
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/*
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* LZMA properties or related bit masks (number of literal
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* context bits, a mask derived from the number of literal
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* position bits, and a mask derived from the number
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* position bits)
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*/
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lc uint32
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literalPosMask uint32
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posMask uint32
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/* If 1, it's a match. Otherwise it's a single 8-bit literal. */
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isMatch [states][posStatesMax]uint16
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/* If 1, it's a repeated match. The distance is one of rep0 .. rep3. */
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isRep [states]uint16
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/*
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* If 0, distance of a repeated match is rep0.
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* Otherwise check is_rep1.
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*/
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isRep0 [states]uint16
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/*
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* If 0, distance of a repeated match is rep1.
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* Otherwise check is_rep2.
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*/
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isRep1 [states]uint16
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/* If 0, distance of a repeated match is rep2. Otherwise it is rep3. */
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isRep2 [states]uint16
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/*
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* If 1, the repeated match has length of one byte. Otherwise
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* the length is decoded from rep_len_decoder.
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*/
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isRep0Long [states][posStatesMax]uint16
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/*
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* Probability tree for the highest two bits of the match
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* distance. There is a separate probability tree for match
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* lengths of 2 (i.e. MATCH_LEN_MIN), 3, 4, and [5, 273].
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*/
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distSlot [distStates][distSlots]uint16
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/*
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* Probility trees for additional bits for match distance
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* when the distance is in the range [4, 127].
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*/
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distSpecial [fullDistances - distModelEnd]uint16
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/*
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* Probability tree for the lowest four bits of a match
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* distance that is equal to or greater than 128.
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*/
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distAlign [alignSize]uint16
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/* Length of a normal match */
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matchLenDec lzmaLenDec
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/* Length of a repeated match */
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repLenDec lzmaLenDec
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/* Probabilities of literals */
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literal [literalCodersMax][literalCoderSize]uint16
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}
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// type of lzma2Dec.sequence
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type lzma2Seq int
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const (
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seqControl lzma2Seq = iota
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seqUncompressed1
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seqUncompressed2
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seqCompressed0
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seqCompressed1
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seqProperties
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seqLZMAPrepare
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seqLZMARun
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seqCopy
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)
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type lzma2Dec struct {
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/* Position in xzDecLZMA2Run. */
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sequence lzma2Seq
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/* Next position after decoding the compressed size of the chunk. */
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nextSequence lzma2Seq
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/* Uncompressed size of LZMA chunk (2 MiB at maximum) */
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uncompressed int
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/*
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* Compressed size of LZMA chunk or compressed/uncompressed
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* size of uncompressed chunk (64 KiB at maximum)
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*/
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compressed int
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/*
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* True if dictionary reset is needed. This is false before
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* the first chunk (LZMA or uncompressed).
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*/
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needDictReset bool
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/*
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* True if new LZMA properties are needed. This is false
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* before the first LZMA chunk.
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*/
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needProps bool
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}
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type xzDecLZMA2 struct {
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/*
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* The order below is important on x86 to reduce code size and
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* it shouldn't hurt on other platforms. Everything up to and
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* including lzma.pos_mask are in the first 128 bytes on x86-32,
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* which allows using smaller instructions to access those
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* variables. On x86-64, fewer variables fit into the first 128
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* bytes, but this is still the best order without sacrificing
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* the readability by splitting the structures.
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*/
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rc rcDec
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dict dictionary
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lzma2 lzma2Dec
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lzma lzmaDec
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/*
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* Temporary buffer which holds small number of input bytes between
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* decoder calls. See lzma2LZMA for details.
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*/
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temp struct {
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buf []byte // slice buf will be backed by bufArray
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bufArray [3 * lzmaInRequired]byte
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}
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}
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/**************
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* Dictionary *
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**************/
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/*
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* Reset the dictionary state. When in single-call mode, set up the beginning
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* of the dictionary to point to the actual output buffer.
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*/
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func dictReset(dict *dictionary, b *xzBuf) {
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dict.start = 0
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dict.pos = 0
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dict.limit = 0
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dict.full = 0
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}
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|
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/* Set dictionary write limit */
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func dictLimit(dict *dictionary, outMax int) {
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if dict.end-dict.pos <= uint32(outMax) {
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dict.limit = dict.end
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} else {
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dict.limit = dict.pos + uint32(outMax)
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}
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}
|
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|
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/* Return true if at least one byte can be written into the dictionary. */
|
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func dictHasSpace(dict *dictionary) bool {
|
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return dict.pos < dict.limit
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}
|
|
|
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/*
|
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* Get a byte from the dictionary at the given distance. The distance is
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* assumed to valid, or as a special case, zero when the dictionary is
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* still empty. This special case is needed for single-call decoding to
|
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* avoid writing a '\x00' to the end of the destination buffer.
|
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*/
|
|
func dictGet(dict *dictionary, dist uint32) uint32 {
|
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var offset uint32 = dict.pos - dist - 1
|
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if dist >= dict.pos {
|
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offset += dict.end
|
|
}
|
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if dict.full > 0 {
|
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return uint32(dict.buf[offset])
|
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}
|
|
return 0
|
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}
|
|
|
|
/*
|
|
* Put one byte into the dictionary. It is assumed that there is space for it.
|
|
*/
|
|
func dictPut(dict *dictionary, byte byte) {
|
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dict.buf[dict.pos] = byte
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dict.pos++
|
|
if dict.full < dict.pos {
|
|
dict.full = dict.pos
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Repeat given number of bytes from the given distance. If the distance is
|
|
* invalid, false is returned. On success, true is returned and *len is
|
|
* updated to indicate how many bytes were left to be repeated.
|
|
*/
|
|
func dictRepeat(dict *dictionary, len *uint32, dist uint32) bool {
|
|
var back uint32
|
|
var left uint32
|
|
if dist >= dict.full || dist >= dict.size {
|
|
return false
|
|
}
|
|
left = dict.limit - dict.pos
|
|
if left > *len {
|
|
left = *len
|
|
}
|
|
*len -= left
|
|
back = dict.pos - dist - 1
|
|
if dist >= dict.pos {
|
|
back += dict.end
|
|
}
|
|
for {
|
|
dict.buf[dict.pos] = dict.buf[back]
|
|
dict.pos++
|
|
back++
|
|
if back == dict.end {
|
|
back = 0
|
|
}
|
|
left--
|
|
if !(left > 0) {
|
|
break
|
|
}
|
|
}
|
|
if dict.full < dict.pos {
|
|
dict.full = dict.pos
|
|
}
|
|
return true
|
|
}
|
|
|
|
/* Copy uncompressed data as is from input to dictionary and output buffers. */
|
|
func dictUncompressed(dict *dictionary, b *xzBuf, left *int) {
|
|
var copySize int
|
|
for *left > 0 && b.inPos < len(b.in) && b.outPos < len(b.out) {
|
|
copySize = len(b.in) - b.inPos
|
|
if copySize > len(b.out)-b.outPos {
|
|
copySize = len(b.out) - b.outPos
|
|
}
|
|
if copySize > int(dict.end-dict.pos) {
|
|
copySize = int(dict.end - dict.pos)
|
|
}
|
|
if copySize > *left {
|
|
copySize = *left
|
|
}
|
|
*left -= copySize
|
|
copy(dict.buf[dict.pos:], b.in[b.inPos:b.inPos+copySize])
|
|
dict.pos += uint32(copySize)
|
|
if dict.full < dict.pos {
|
|
dict.full = dict.pos
|
|
}
|
|
if dict.pos == dict.end {
|
|
dict.pos = 0
|
|
}
|
|
copy(b.out[b.outPos:], b.in[b.inPos:b.inPos+copySize])
|
|
dict.start = dict.pos
|
|
b.outPos += copySize
|
|
b.inPos += copySize
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Flush pending data from dictionary to b.out. It is assumed that there is
|
|
* enough space in b.out. This is guaranteed because caller uses dictLimit
|
|
* before decoding data into the dictionary.
|
|
*/
|
|
func dictFlush(dict *dictionary, b *xzBuf) int {
|
|
var copySize int = int(dict.pos - dict.start)
|
|
if dict.pos == dict.end {
|
|
dict.pos = 0
|
|
}
|
|
copy(b.out[b.outPos:], dict.buf[dict.start:dict.start+uint32(copySize)])
|
|
dict.start = dict.pos
|
|
b.outPos += copySize
|
|
return copySize
|
|
}
|
|
|
|
/*****************
|
|
* Range decoder *
|
|
*****************/
|
|
|
|
/* Reset the range decoder. */
|
|
func rcReset(rc *rcDec) {
|
|
rc.rnge = ^uint32(0)
|
|
rc.code = 0
|
|
rc.initBytesLeft = rcInitBytes
|
|
}
|
|
|
|
/*
|
|
* Read the first five initial bytes into rc->code if they haven't been
|
|
* read already. (Yes, the first byte gets completely ignored.)
|
|
*/
|
|
func rcReadInit(rc *rcDec, b *xzBuf) bool {
|
|
for rc.initBytesLeft > 0 {
|
|
if b.inPos == len(b.in) {
|
|
return false
|
|
}
|
|
rc.code = rc.code<<8 + uint32(b.in[b.inPos])
|
|
b.inPos++
|
|
rc.initBytesLeft--
|
|
}
|
|
return true
|
|
}
|
|
|
|
/* Return true if there may not be enough input for the next decoding loop. */
|
|
func rcLimitExceeded(rc *rcDec) bool {
|
|
return rc.inPos > rc.inLimit
|
|
}
|
|
|
|
/*
|
|
* Return true if it is possible (from point of view of range decoder) that
|
|
* we have reached the end of the LZMA chunk.
|
|
*/
|
|
func rcIsFinished(rc *rcDec) bool {
|
|
return rc.code == 0
|
|
}
|
|
|
|
/* Read the next input byte if needed. */
|
|
func rcNormalize(rc *rcDec) {
|
|
if rc.rnge < rcTopValue {
|
|
rc.rnge <<= rcShiftBits
|
|
rc.code = rc.code<<rcShiftBits + uint32(rc.in[rc.inPos])
|
|
rc.inPos++
|
|
}
|
|
}
|
|
|
|
/* Decode one bit. */
|
|
func rcBit(rc *rcDec, prob *uint16) bool {
|
|
var bound uint32
|
|
var bit bool
|
|
rcNormalize(rc)
|
|
bound = (rc.rnge >> rcBitModelTotalBits) * uint32(*prob)
|
|
if rc.code < bound {
|
|
rc.rnge = bound
|
|
*prob += (rcBitModelTotal - *prob) >> rcMoveBits
|
|
bit = false
|
|
} else {
|
|
rc.rnge -= bound
|
|
rc.code -= bound
|
|
*prob -= *prob >> rcMoveBits
|
|
bit = true
|
|
}
|
|
return bit
|
|
}
|
|
|
|
/* Decode a bittree starting from the most significant bit. */
|
|
func rcBittree(rc *rcDec, probs []uint16, limit uint32) uint32 {
|
|
var symbol uint32 = 1
|
|
for {
|
|
if rcBit(rc, &probs[symbol-1]) {
|
|
symbol = symbol<<1 + 1
|
|
} else {
|
|
symbol <<= 1
|
|
}
|
|
if !(symbol < limit) {
|
|
break
|
|
}
|
|
}
|
|
return symbol
|
|
}
|
|
|
|
/* Decode a bittree starting from the least significant bit. */
|
|
func rcBittreeReverse(rc *rcDec, probs []uint16, dest *uint32, limit uint32) {
|
|
var symbol uint32 = 1
|
|
var i uint32 = 0
|
|
for {
|
|
if rcBit(rc, &probs[symbol-1]) {
|
|
symbol = symbol<<1 + 1
|
|
*dest += 1 << i
|
|
} else {
|
|
symbol <<= 1
|
|
}
|
|
i++
|
|
if !(i < limit) {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Decode direct bits (fixed fifty-fifty probability) */
|
|
func rcDirect(rc *rcDec, dest *uint32, limit uint32) {
|
|
var mask uint32
|
|
for {
|
|
rcNormalize(rc)
|
|
rc.rnge >>= 1
|
|
rc.code -= rc.rnge
|
|
mask = 0 - rc.code>>31
|
|
rc.code += rc.rnge & mask
|
|
*dest = *dest<<1 + mask + 1
|
|
limit--
|
|
if !(limit > 0) {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
/********
|
|
* LZMA *
|
|
********/
|
|
|
|
/* Get pointer to literal coder probability array. */
|
|
func lzmaLiteralProbs(s *xzDecLZMA2) []uint16 {
|
|
var prevByte uint32 = dictGet(&s.dict, 0)
|
|
var low uint32 = prevByte >> (8 - s.lzma.lc)
|
|
var high uint32 = (s.dict.pos & s.lzma.literalPosMask) << s.lzma.lc
|
|
return s.lzma.literal[low+high][:]
|
|
}
|
|
|
|
/* Decode a literal (one 8-bit byte) */
|
|
func lzmaLiteral(s *xzDecLZMA2) {
|
|
var probs []uint16
|
|
var symbol uint32
|
|
var matchByte uint32
|
|
var matchBit uint32
|
|
var offset uint32
|
|
var i uint32
|
|
probs = lzmaLiteralProbs(s)
|
|
if lzmaStateIsLiteral(s.lzma.state) {
|
|
symbol = rcBittree(&s.rc, probs[1:], 0x100)
|
|
} else {
|
|
symbol = 1
|
|
matchByte = dictGet(&s.dict, s.lzma.rep0) << 1
|
|
offset = 0x100
|
|
for {
|
|
matchBit = matchByte & offset
|
|
matchByte <<= 1
|
|
i = offset + matchBit + symbol
|
|
if rcBit(&s.rc, &probs[i]) {
|
|
symbol = symbol<<1 + 1
|
|
offset &= matchBit
|
|
} else {
|
|
symbol <<= 1
|
|
offset &= ^matchBit
|
|
}
|
|
if !(symbol < 0x100) {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
dictPut(&s.dict, byte(symbol))
|
|
lzmaStateLiteral(&s.lzma.state)
|
|
}
|
|
|
|
/* Decode the length of the match into s.lzma.len. */
|
|
func lzmaLen(s *xzDecLZMA2, l *lzmaLenDec, posState uint32) {
|
|
var probs []uint16
|
|
var limit uint32
|
|
switch {
|
|
case !rcBit(&s.rc, &l.choice):
|
|
probs = l.low[posState][:]
|
|
limit = lenLowSymbols
|
|
s.lzma.len = matchLenMin
|
|
case !rcBit(&s.rc, &l.choice2):
|
|
probs = l.mid[posState][:]
|
|
limit = lenMidSymbols
|
|
s.lzma.len = matchLenMin + lenLowSymbols
|
|
default:
|
|
probs = l.high[:]
|
|
limit = lenHighSymbols
|
|
s.lzma.len = matchLenMin + lenLowSymbols + lenMidSymbols
|
|
}
|
|
s.lzma.len += rcBittree(&s.rc, probs[1:], limit) - limit
|
|
}
|
|
|
|
/* Decode a match. The distance will be stored in s.lzma.rep0. */
|
|
func lzmaMatch(s *xzDecLZMA2, posState uint32) {
|
|
var probs []uint16
|
|
var distSlot uint32
|
|
var limit uint32
|
|
lzmaStateMatch(&s.lzma.state)
|
|
s.lzma.rep3 = s.lzma.rep2
|
|
s.lzma.rep2 = s.lzma.rep1
|
|
s.lzma.rep1 = s.lzma.rep0
|
|
lzmaLen(s, &s.lzma.matchLenDec, posState)
|
|
probs = s.lzma.distSlot[lzmaGetDistState(s.lzma.len)][:]
|
|
distSlot = rcBittree(&s.rc, probs[1:], distSlots) - distSlots
|
|
if distSlot < distModelStart {
|
|
s.lzma.rep0 = distSlot
|
|
} else {
|
|
limit = distSlot>>1 - 1
|
|
s.lzma.rep0 = 2 + distSlot&1
|
|
if distSlot < distModelEnd {
|
|
s.lzma.rep0 <<= limit
|
|
probs = s.lzma.distSpecial[s.lzma.rep0-distSlot:]
|
|
rcBittreeReverse(&s.rc, probs, &s.lzma.rep0, limit)
|
|
} else {
|
|
rcDirect(&s.rc, &s.lzma.rep0, limit-alignBits)
|
|
s.lzma.rep0 <<= alignBits
|
|
rcBittreeReverse(
|
|
&s.rc, s.lzma.distAlign[1:], &s.lzma.rep0, alignBits)
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Decode a repeated match. The distance is one of the four most recently
|
|
* seen matches. The distance will be stored in s.lzma.rep0.
|
|
*/
|
|
func lzmaRepMatch(s *xzDecLZMA2, posState uint32) {
|
|
var tmp uint32
|
|
if !rcBit(&s.rc, &s.lzma.isRep0[s.lzma.state]) {
|
|
if !rcBit(&s.rc, &s.lzma.isRep0Long[s.lzma.state][posState]) {
|
|
lzmaStateShortRep(&s.lzma.state)
|
|
s.lzma.len = 1
|
|
return
|
|
}
|
|
} else {
|
|
if !rcBit(&s.rc, &s.lzma.isRep1[s.lzma.state]) {
|
|
tmp = s.lzma.rep1
|
|
} else {
|
|
if !rcBit(&s.rc, &s.lzma.isRep2[s.lzma.state]) {
|
|
tmp = s.lzma.rep2
|
|
} else {
|
|
tmp = s.lzma.rep3
|
|
s.lzma.rep3 = s.lzma.rep2
|
|
}
|
|
s.lzma.rep2 = s.lzma.rep1
|
|
}
|
|
s.lzma.rep1 = s.lzma.rep0
|
|
s.lzma.rep0 = tmp
|
|
}
|
|
lzmaStateLongRep(&s.lzma.state)
|
|
lzmaLen(s, &s.lzma.repLenDec, posState)
|
|
}
|
|
|
|
/* LZMA decoder core */
|
|
func lzmaMain(s *xzDecLZMA2) bool {
|
|
var posState uint32
|
|
/*
|
|
* If the dictionary was reached during the previous call, try to
|
|
* finish the possibly pending repeat in the dictionary.
|
|
*/
|
|
if dictHasSpace(&s.dict) && s.lzma.len > 0 {
|
|
dictRepeat(&s.dict, &s.lzma.len, s.lzma.rep0)
|
|
}
|
|
/*
|
|
* Decode more LZMA symbols. One iteration may consume up to
|
|
* lzmaInRequired - 1 bytes.
|
|
*/
|
|
for dictHasSpace(&s.dict) && !rcLimitExceeded(&s.rc) {
|
|
posState = s.dict.pos & s.lzma.posMask
|
|
if !rcBit(&s.rc, &s.lzma.isMatch[s.lzma.state][posState]) {
|
|
lzmaLiteral(s)
|
|
} else {
|
|
if rcBit(&s.rc, &s.lzma.isRep[s.lzma.state]) {
|
|
lzmaRepMatch(s, posState)
|
|
} else {
|
|
lzmaMatch(s, posState)
|
|
}
|
|
if !dictRepeat(&s.dict, &s.lzma.len, s.lzma.rep0) {
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* Having the range decoder always normalized when we are outside
|
|
* this function makes it easier to correctly handle end of the chunk.
|
|
*/
|
|
rcNormalize(&s.rc)
|
|
return true
|
|
}
|
|
|
|
/*
|
|
* Reset the LZMA decoder and range decoder state. Dictionary is not reset
|
|
* here, because LZMA state may be reset without resetting the dictionary.
|
|
*/
|
|
func lzmaReset(s *xzDecLZMA2) {
|
|
s.lzma.state = stateLitLit
|
|
s.lzma.rep0 = 0
|
|
s.lzma.rep1 = 0
|
|
s.lzma.rep2 = 0
|
|
s.lzma.rep3 = 0
|
|
/* All probabilities are initialized to the same value, v */
|
|
v := uint16(rcBitModelTotal / 2)
|
|
s.lzma.matchLenDec.choice = v
|
|
s.lzma.matchLenDec.choice2 = v
|
|
s.lzma.repLenDec.choice = v
|
|
s.lzma.repLenDec.choice2 = v
|
|
for _, m := range [][]uint16{
|
|
s.lzma.isRep[:], s.lzma.isRep0[:], s.lzma.isRep1[:],
|
|
s.lzma.isRep2[:], s.lzma.distSpecial[:], s.lzma.distAlign[:],
|
|
s.lzma.matchLenDec.high[:], s.lzma.repLenDec.high[:],
|
|
} {
|
|
for j := range m {
|
|
m[j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.isMatch {
|
|
for j := range s.lzma.isMatch[i] {
|
|
s.lzma.isMatch[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.isRep0Long {
|
|
for j := range s.lzma.isRep0Long[i] {
|
|
s.lzma.isRep0Long[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.distSlot {
|
|
for j := range s.lzma.distSlot[i] {
|
|
s.lzma.distSlot[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.literal {
|
|
for j := range s.lzma.literal[i] {
|
|
s.lzma.literal[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.matchLenDec.low {
|
|
for j := range s.lzma.matchLenDec.low[i] {
|
|
s.lzma.matchLenDec.low[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.matchLenDec.mid {
|
|
for j := range s.lzma.matchLenDec.mid[i] {
|
|
s.lzma.matchLenDec.mid[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.repLenDec.low {
|
|
for j := range s.lzma.repLenDec.low[i] {
|
|
s.lzma.repLenDec.low[i][j] = v
|
|
}
|
|
}
|
|
for i := range s.lzma.repLenDec.mid {
|
|
for j := range s.lzma.repLenDec.mid[i] {
|
|
s.lzma.repLenDec.mid[i][j] = v
|
|
}
|
|
}
|
|
rcReset(&s.rc)
|
|
}
|
|
|
|
/*
|
|
* Decode and validate LZMA properties (lc/lp/pb) and calculate the bit masks
|
|
* from the decoded lp and pb values. On success, the LZMA decoder state is
|
|
* reset and true is returned.
|
|
*/
|
|
func lzmaProps(s *xzDecLZMA2, props byte) bool {
|
|
if props > (4*5+4)*9+8 {
|
|
return false
|
|
}
|
|
s.lzma.posMask = 0
|
|
for props >= 9*5 {
|
|
props -= 9 * 5
|
|
s.lzma.posMask++
|
|
}
|
|
s.lzma.posMask = 1<<s.lzma.posMask - 1
|
|
s.lzma.literalPosMask = 0
|
|
for props >= 9 {
|
|
props -= 9
|
|
s.lzma.literalPosMask++
|
|
}
|
|
s.lzma.lc = uint32(props)
|
|
if s.lzma.lc+s.lzma.literalPosMask > 4 {
|
|
return false
|
|
}
|
|
s.lzma.literalPosMask = 1<<s.lzma.literalPosMask - 1
|
|
lzmaReset(s)
|
|
return true
|
|
}
|
|
|
|
/*********
|
|
* LZMA2 *
|
|
*********/
|
|
|
|
/*
|
|
* The LZMA decoder assumes that if the input limit (s.rc.inLimit) hasn't
|
|
* been exceeded, it is safe to read up to lzmaInRequired bytes. This
|
|
* wrapper function takes care of making the LZMA decoder's assumption safe.
|
|
*
|
|
* As long as there is plenty of input left to be decoded in the current LZMA
|
|
* chunk, we decode directly from the caller-supplied input buffer until
|
|
* there's lzmaInRequired bytes left. Those remaining bytes are copied into
|
|
* s.temp.buf, which (hopefully) gets filled on the next call to this
|
|
* function. We decode a few bytes from the temporary buffer so that we can
|
|
* continue decoding from the caller-supplied input buffer again.
|
|
*/
|
|
func lzma2LZMA(s *xzDecLZMA2, b *xzBuf) bool {
|
|
var inAvail int
|
|
var tmp int
|
|
inAvail = len(b.in) - b.inPos
|
|
if len(s.temp.buf) > 0 || s.lzma2.compressed == 0 {
|
|
tmp = 2*lzmaInRequired - len(s.temp.buf)
|
|
if tmp > s.lzma2.compressed-len(s.temp.buf) {
|
|
tmp = s.lzma2.compressed - len(s.temp.buf)
|
|
}
|
|
if tmp > inAvail {
|
|
tmp = inAvail
|
|
}
|
|
copy(s.temp.bufArray[len(s.temp.buf):], b.in[b.inPos:b.inPos+tmp])
|
|
switch {
|
|
case len(s.temp.buf)+tmp == s.lzma2.compressed:
|
|
for i := len(s.temp.buf) + tmp; i < len(s.temp.bufArray); i++ {
|
|
s.temp.bufArray[i] = 0
|
|
}
|
|
s.rc.inLimit = len(s.temp.buf) + tmp
|
|
case len(s.temp.buf)+tmp < lzmaInRequired:
|
|
s.temp.buf = s.temp.bufArray[:len(s.temp.buf)+tmp]
|
|
b.inPos += tmp
|
|
return true
|
|
default:
|
|
s.rc.inLimit = len(s.temp.buf) + tmp - lzmaInRequired
|
|
}
|
|
s.rc.in = s.temp.bufArray[:]
|
|
s.rc.inPos = 0
|
|
if !lzmaMain(s) || s.rc.inPos > len(s.temp.buf)+tmp {
|
|
return false
|
|
}
|
|
s.lzma2.compressed -= s.rc.inPos
|
|
if s.rc.inPos < len(s.temp.buf) {
|
|
copy(s.temp.buf, s.temp.buf[s.rc.inPos:])
|
|
s.temp.buf = s.temp.buf[:len(s.temp.buf)-s.rc.inPos]
|
|
return true
|
|
}
|
|
b.inPos += s.rc.inPos - len(s.temp.buf)
|
|
s.temp.buf = nil
|
|
}
|
|
inAvail = len(b.in) - b.inPos
|
|
if inAvail >= lzmaInRequired {
|
|
s.rc.in = b.in
|
|
s.rc.inPos = b.inPos
|
|
if inAvail >= s.lzma2.compressed+lzmaInRequired {
|
|
s.rc.inLimit = b.inPos + s.lzma2.compressed
|
|
} else {
|
|
s.rc.inLimit = len(b.in) - lzmaInRequired
|
|
}
|
|
if !lzmaMain(s) {
|
|
return false
|
|
}
|
|
inAvail = s.rc.inPos - b.inPos
|
|
if inAvail > s.lzma2.compressed {
|
|
return false
|
|
}
|
|
s.lzma2.compressed -= inAvail
|
|
b.inPos = s.rc.inPos
|
|
}
|
|
inAvail = len(b.in) - b.inPos
|
|
if inAvail < lzmaInRequired {
|
|
if inAvail > s.lzma2.compressed {
|
|
inAvail = s.lzma2.compressed
|
|
}
|
|
s.temp.buf = s.temp.bufArray[:inAvail]
|
|
copy(s.temp.buf, b.in[b.inPos:])
|
|
b.inPos += inAvail
|
|
}
|
|
return true
|
|
}
|
|
|
|
/*
|
|
* Take care of the LZMA2 control layer, and forward the job of actual LZMA
|
|
* decoding or copying of uncompressed chunks to other functions.
|
|
*/
|
|
func xzDecLZMA2Run(s *xzDecLZMA2, b *xzBuf) xzRet {
|
|
var tmp int
|
|
for b.inPos < len(b.in) || s.lzma2.sequence == seqLZMARun {
|
|
switch s.lzma2.sequence {
|
|
case seqControl:
|
|
/*
|
|
* LZMA2 control byte
|
|
*
|
|
* Exact values:
|
|
* 0x00 End marker
|
|
* 0x01 Dictionary reset followed by
|
|
* an uncompressed chunk
|
|
* 0x02 Uncompressed chunk (no dictionary reset)
|
|
*
|
|
* Highest three bits (s.control & 0xE0):
|
|
* 0xE0 Dictionary reset, new properties and state
|
|
* reset, followed by LZMA compressed chunk
|
|
* 0xC0 New properties and state reset, followed
|
|
* by LZMA compressed chunk (no dictionary
|
|
* reset)
|
|
* 0xA0 State reset using old properties,
|
|
* followed by LZMA compressed chunk (no
|
|
* dictionary reset)
|
|
* 0x80 LZMA chunk (no dictionary or state reset)
|
|
*
|
|
* For LZMA compressed chunks, the lowest five bits
|
|
* (s.control & 1F) are the highest bits of the
|
|
* uncompressed size (bits 16-20).
|
|
*
|
|
* A new LZMA2 stream must begin with a dictionary
|
|
* reset. The first LZMA chunk must set new
|
|
* properties and reset the LZMA state.
|
|
*
|
|
* Values that don't match anything described above
|
|
* are invalid and we return xzDataError.
|
|
*/
|
|
tmp = int(b.in[b.inPos])
|
|
b.inPos++
|
|
if tmp == 0x00 {
|
|
return xzStreamEnd
|
|
}
|
|
switch {
|
|
case tmp >= 0xe0 || tmp == 0x01:
|
|
s.lzma2.needProps = true
|
|
s.lzma2.needDictReset = false
|
|
dictReset(&s.dict, b)
|
|
case s.lzma2.needDictReset:
|
|
return xzDataError
|
|
}
|
|
if tmp >= 0x80 {
|
|
s.lzma2.uncompressed = (tmp & 0x1f) << 16
|
|
s.lzma2.sequence = seqUncompressed1
|
|
switch {
|
|
case tmp >= 0xc0:
|
|
/*
|
|
* When there are new properties,
|
|
* state reset is done at
|
|
* seqProperties.
|
|
*/
|
|
s.lzma2.needProps = false
|
|
s.lzma2.nextSequence = seqProperties
|
|
case s.lzma2.needProps:
|
|
return xzDataError
|
|
default:
|
|
s.lzma2.nextSequence = seqLZMAPrepare
|
|
if tmp >= 0xa0 {
|
|
lzmaReset(s)
|
|
}
|
|
}
|
|
} else {
|
|
if tmp > 0x02 {
|
|
return xzDataError
|
|
}
|
|
s.lzma2.sequence = seqCompressed0
|
|
s.lzma2.nextSequence = seqCopy
|
|
}
|
|
case seqUncompressed1:
|
|
s.lzma2.uncompressed += int(b.in[b.inPos]) << 8
|
|
b.inPos++
|
|
s.lzma2.sequence = seqUncompressed2
|
|
case seqUncompressed2:
|
|
s.lzma2.uncompressed += int(b.in[b.inPos]) + 1
|
|
b.inPos++
|
|
s.lzma2.sequence = seqCompressed0
|
|
case seqCompressed0:
|
|
s.lzma2.compressed += int(b.in[b.inPos]) << 8
|
|
b.inPos++
|
|
s.lzma2.sequence = seqCompressed1
|
|
case seqCompressed1:
|
|
s.lzma2.compressed += int(b.in[b.inPos]) + 1
|
|
b.inPos++
|
|
s.lzma2.sequence = s.lzma2.nextSequence
|
|
case seqProperties:
|
|
if !lzmaProps(s, b.in[b.inPos]) {
|
|
return xzDataError
|
|
}
|
|
b.inPos++
|
|
s.lzma2.sequence = seqLZMAPrepare
|
|
fallthrough
|
|
case seqLZMAPrepare:
|
|
if s.lzma2.compressed < rcInitBytes {
|
|
return xzDataError
|
|
}
|
|
if !rcReadInit(&s.rc, b) {
|
|
return xzOK
|
|
}
|
|
s.lzma2.compressed -= rcInitBytes
|
|
s.lzma2.sequence = seqLZMARun
|
|
fallthrough
|
|
case seqLZMARun:
|
|
/*
|
|
* Set dictionary limit to indicate how much we want
|
|
* to be encoded at maximum. Decode new data into the
|
|
* dictionary. Flush the new data from dictionary to
|
|
* b.out. Check if we finished decoding this chunk.
|
|
* In case the dictionary got full but we didn't fill
|
|
* the output buffer yet, we may run this loop
|
|
* multiple times without changing s.lzma2.sequence.
|
|
*/
|
|
outMax := len(b.out) - b.outPos
|
|
if outMax > s.lzma2.uncompressed {
|
|
outMax = s.lzma2.uncompressed
|
|
}
|
|
dictLimit(&s.dict, outMax)
|
|
if !lzma2LZMA(s, b) {
|
|
return xzDataError
|
|
}
|
|
s.lzma2.uncompressed -= dictFlush(&s.dict, b)
|
|
switch {
|
|
case s.lzma2.uncompressed == 0:
|
|
if s.lzma2.compressed > 0 || s.lzma.len > 0 ||
|
|
!rcIsFinished(&s.rc) {
|
|
return xzDataError
|
|
}
|
|
rcReset(&s.rc)
|
|
s.lzma2.sequence = seqControl
|
|
case b.outPos == len(b.out) ||
|
|
b.inPos == len(b.in) &&
|
|
len(s.temp.buf) < s.lzma2.compressed:
|
|
return xzOK
|
|
}
|
|
case seqCopy:
|
|
dictUncompressed(&s.dict, b, &s.lzma2.compressed)
|
|
if s.lzma2.compressed > 0 {
|
|
return xzOK
|
|
}
|
|
s.lzma2.sequence = seqControl
|
|
}
|
|
}
|
|
return xzOK
|
|
}
|
|
|
|
/*
|
|
* Allocate memory for LZMA2 decoder. xzDecLZMA2Reset must be used
|
|
* before calling xzDecLZMA2Run.
|
|
*/
|
|
func xzDecLZMA2Create(dictMax uint32) *xzDecLZMA2 {
|
|
s := new(xzDecLZMA2)
|
|
s.dict.sizeMax = dictMax
|
|
return s
|
|
}
|
|
|
|
/*
|
|
* Decode the LZMA2 properties (one byte) and reset the decoder. Return
|
|
* xzOK on success, xzMemlimitError if the preallocated dictionary is not
|
|
* big enough, and xzOptionsError if props indicates something that this
|
|
* decoder doesn't support.
|
|
*/
|
|
func xzDecLZMA2Reset(s *xzDecLZMA2, props byte) xzRet {
|
|
if props > 40 {
|
|
return xzOptionsError // Bigger than 4 GiB
|
|
}
|
|
if props == 40 {
|
|
s.dict.size = ^uint32(0)
|
|
} else {
|
|
s.dict.size = uint32(2 + props&1)
|
|
s.dict.size <<= props>>1 + 11
|
|
}
|
|
if s.dict.size > s.dict.sizeMax {
|
|
return xzMemlimitError
|
|
}
|
|
s.dict.end = s.dict.size
|
|
if len(s.dict.buf) < int(s.dict.size) {
|
|
s.dict.buf = make([]byte, s.dict.size)
|
|
}
|
|
s.lzma.len = 0
|
|
s.lzma2.sequence = seqControl
|
|
s.lzma2.compressed = 0
|
|
s.lzma2.uncompressed = 0
|
|
s.lzma2.needDictReset = true
|
|
s.temp.buf = nil
|
|
return xzOK
|
|
}
|