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https://github.com/go-gitea/gitea
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684b7a999f
* 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>
170 lines
4.9 KiB
Go
Vendored
170 lines
4.9 KiB
Go
Vendored
package brotli
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/* Copyright 2018 Google Inc. All Rights Reserved.
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Distributed under MIT license.
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See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
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*/
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/* NOTE: this hasher does not search in the dictionary. It is used as
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backup-hasher, the main hasher already searches in it. */
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const kRollingHashMul32 uint32 = 69069
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const kInvalidPosHashRolling uint32 = 0xffffffff
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/* This hasher uses a longer forward length, but returning a higher value here
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will hurt compression by the main hasher when combined with a composite
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hasher. The hasher tests for forward itself instead. */
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func (*hashRolling) HashTypeLength() uint {
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return 4
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}
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func (*hashRolling) StoreLookahead() uint {
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return 4
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}
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/* Computes a code from a single byte. A lookup table of 256 values could be
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used, but simply adding 1 works about as good. */
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func (*hashRolling) HashByte(b byte) uint32 {
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return uint32(b) + 1
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}
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func (h *hashRolling) HashRollingFunctionInitial(state uint32, add byte, factor uint32) uint32 {
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return uint32(factor*state + h.HashByte(add))
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}
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func (h *hashRolling) HashRollingFunction(state uint32, add byte, rem byte, factor uint32, factor_remove uint32) uint32 {
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return uint32(factor*state + h.HashByte(add) - factor_remove*h.HashByte(rem))
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}
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/* Rolling hash for long distance long string matches. Stores one position
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per bucket, bucket key is computed over a long region. */
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type hashRolling struct {
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hasherCommon
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jump int
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state uint32
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table []uint32
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next_ix uint
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chunk_len uint32
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factor uint32
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factor_remove uint32
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}
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func (h *hashRolling) Initialize(params *encoderParams) {
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h.state = 0
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h.next_ix = 0
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h.factor = kRollingHashMul32
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/* Compute the factor of the oldest byte to remove: factor**steps modulo
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0xffffffff (the multiplications rely on 32-bit overflow) */
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h.factor_remove = 1
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for i := 0; i < 32; i += h.jump {
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h.factor_remove *= h.factor
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}
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h.table = make([]uint32, 16777216)
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for i := 0; i < 16777216; i++ {
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h.table[i] = kInvalidPosHashRolling
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}
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}
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func (h *hashRolling) Prepare(one_shot bool, input_size uint, data []byte) {
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/* Too small size, cannot use this hasher. */
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if input_size < 32 {
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return
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}
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h.state = 0
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for i := 0; i < 32; i += h.jump {
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h.state = h.HashRollingFunctionInitial(h.state, data[i], h.factor)
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}
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}
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func (*hashRolling) Store(data []byte, mask uint, ix uint) {
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}
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func (*hashRolling) StoreRange(data []byte, mask uint, ix_start uint, ix_end uint) {
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}
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func (h *hashRolling) StitchToPreviousBlock(num_bytes uint, position uint, ringbuffer []byte, ring_buffer_mask uint) {
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var position_masked uint
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/* In this case we must re-initialize the hasher from scratch from the
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current position. */
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var available uint = num_bytes
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if position&uint(h.jump-1) != 0 {
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var diff uint = uint(h.jump) - (position & uint(h.jump-1))
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if diff > available {
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available = 0
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} else {
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available = available - diff
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}
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position += diff
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}
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position_masked = position & ring_buffer_mask
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/* wrapping around ringbuffer not handled. */
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if available > ring_buffer_mask-position_masked {
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available = ring_buffer_mask - position_masked
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}
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h.Prepare(false, available, ringbuffer[position&ring_buffer_mask:])
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h.next_ix = position
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}
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func (*hashRolling) PrepareDistanceCache(distance_cache []int) {
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}
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func (h *hashRolling) FindLongestMatch(dictionary *encoderDictionary, data []byte, ring_buffer_mask uint, distance_cache []int, cur_ix uint, max_length uint, max_backward uint, gap uint, max_distance uint, out *hasherSearchResult) {
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var cur_ix_masked uint = cur_ix & ring_buffer_mask
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var pos uint = h.next_ix
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if cur_ix&uint(h.jump-1) != 0 {
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return
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}
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/* Not enough lookahead */
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if max_length < 32 {
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return
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}
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for pos = h.next_ix; pos <= cur_ix; pos += uint(h.jump) {
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var code uint32 = h.state & ((16777216 * 64) - 1)
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var rem byte = data[pos&ring_buffer_mask]
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var add byte = data[(pos+32)&ring_buffer_mask]
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var found_ix uint = uint(kInvalidPosHashRolling)
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h.state = h.HashRollingFunction(h.state, add, rem, h.factor, h.factor_remove)
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if code < 16777216 {
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found_ix = uint(h.table[code])
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h.table[code] = uint32(pos)
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if pos == cur_ix && uint32(found_ix) != kInvalidPosHashRolling {
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/* The cast to 32-bit makes backward distances up to 4GB work even
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if cur_ix is above 4GB, despite using 32-bit values in the table. */
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var backward uint = uint(uint32(cur_ix - found_ix))
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if backward <= max_backward {
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var found_ix_masked uint = found_ix & ring_buffer_mask
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var len uint = findMatchLengthWithLimit(data[found_ix_masked:], data[cur_ix_masked:], max_length)
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if len >= 4 && len > out.len {
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var score uint = backwardReferenceScore(uint(len), backward)
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if score > out.score {
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out.len = uint(len)
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out.distance = backward
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out.score = score
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out.len_code_delta = 0
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}
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}
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}
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}
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}
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}
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h.next_ix = cur_ix + uint(h.jump)
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}
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