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gitea/vendor/github.com/andybalholm/brotli/block_splitter.go
6543 12a1f914f4
Vendor Update Go Libs (#13166)
* update github.com/alecthomas/chroma v0.8.0 -> v0.8.1

* github.com/blevesearch/bleve v1.0.10 -> v1.0.12

* editorconfig-core-go v2.1.1 -> v2.3.7

* github.com/gliderlabs/ssh v0.2.2 -> v0.3.1

* migrate editorconfig.ParseBytes to Parse

* github.com/shurcooL/vfsgen to 0d455de96546

* github.com/go-git/go-git/v5 v5.1.0 -> v5.2.0

* github.com/google/uuid v1.1.1 -> v1.1.2

* github.com/huandu/xstrings v1.3.0 -> v1.3.2

* github.com/klauspost/compress v1.10.11 -> v1.11.1

* github.com/markbates/goth v1.61.2 -> v1.65.0

* github.com/mattn/go-sqlite3 v1.14.0 -> v1.14.4

* github.com/mholt/archiver v3.3.0 -> v3.3.2

* github.com/microcosm-cc/bluemonday 4f7140c49acb -> v1.0.4

* github.com/minio/minio-go v7.0.4 -> v7.0.5

* github.com/olivere/elastic v7.0.9 -> v7.0.20

* github.com/urfave/cli v1.20.0 -> v1.22.4

* github.com/prometheus/client_golang v1.1.0 -> v1.8.0

* github.com/xanzy/go-gitlab v0.37.0 -> v0.38.1

* mvdan.cc/xurls v2.1.0 -> v2.2.0

Co-authored-by: Lauris BH <lauris@nix.lv>
2020-10-16 01:06:27 -04:00

145 lines
4.0 KiB
Go
Vendored

package brotli
/* Copyright 2013 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
/* Block split point selection utilities. */
type blockSplit struct {
num_types uint
num_blocks uint
types []byte
lengths []uint32
types_alloc_size uint
lengths_alloc_size uint
}
const (
kMaxLiteralHistograms uint = 100
kMaxCommandHistograms uint = 50
kLiteralBlockSwitchCost float64 = 28.1
kCommandBlockSwitchCost float64 = 13.5
kDistanceBlockSwitchCost float64 = 14.6
kLiteralStrideLength uint = 70
kCommandStrideLength uint = 40
kSymbolsPerLiteralHistogram uint = 544
kSymbolsPerCommandHistogram uint = 530
kSymbolsPerDistanceHistogram uint = 544
kMinLengthForBlockSplitting uint = 128
kIterMulForRefining uint = 2
kMinItersForRefining uint = 100
)
func countLiterals(cmds []command) uint {
var total_length uint = 0
/* Count how many we have. */
for i := range cmds {
total_length += uint(cmds[i].insert_len_)
}
return total_length
}
func copyLiteralsToByteArray(cmds []command, data []byte, offset uint, mask uint, literals []byte) {
var pos uint = 0
var from_pos uint = offset & mask
for i := range cmds {
var insert_len uint = uint(cmds[i].insert_len_)
if from_pos+insert_len > mask {
var head_size uint = mask + 1 - from_pos
copy(literals[pos:], data[from_pos:][:head_size])
from_pos = 0
pos += head_size
insert_len -= head_size
}
if insert_len > 0 {
copy(literals[pos:], data[from_pos:][:insert_len])
pos += insert_len
}
from_pos = uint((uint32(from_pos+insert_len) + commandCopyLen(&cmds[i])) & uint32(mask))
}
}
func myRand(seed *uint32) uint32 {
/* Initial seed should be 7. In this case, loop length is (1 << 29). */
*seed *= 16807
return *seed
}
func bitCost(count uint) float64 {
if count == 0 {
return -2.0
} else {
return fastLog2(count)
}
}
const histogramsPerBatch = 64
const clustersPerBatch = 16
func initBlockSplit(self *blockSplit) {
self.num_types = 0
self.num_blocks = 0
self.types = self.types[:0]
self.lengths = self.lengths[:0]
self.types_alloc_size = 0
self.lengths_alloc_size = 0
}
func splitBlock(cmds []command, data []byte, pos uint, mask uint, params *encoderParams, literal_split *blockSplit, insert_and_copy_split *blockSplit, dist_split *blockSplit) {
{
var literals_count uint = countLiterals(cmds)
var literals []byte = make([]byte, literals_count)
/* Create a continuous array of literals. */
copyLiteralsToByteArray(cmds, data, pos, mask, literals)
/* Create the block split on the array of literals.
Literal histograms have alphabet size 256. */
splitByteVectorLiteral(literals, literals_count, kSymbolsPerLiteralHistogram, kMaxLiteralHistograms, kLiteralStrideLength, kLiteralBlockSwitchCost, params, literal_split)
literals = nil
}
{
var insert_and_copy_codes []uint16 = make([]uint16, len(cmds))
/* Compute prefix codes for commands. */
for i := range cmds {
insert_and_copy_codes[i] = cmds[i].cmd_prefix_
}
/* Create the block split on the array of command prefixes. */
splitByteVectorCommand(insert_and_copy_codes, kSymbolsPerCommandHistogram, kMaxCommandHistograms, kCommandStrideLength, kCommandBlockSwitchCost, params, insert_and_copy_split)
/* TODO: reuse for distances? */
insert_and_copy_codes = nil
}
{
var distance_prefixes []uint16 = make([]uint16, len(cmds))
var j uint = 0
/* Create a continuous array of distance prefixes. */
for i := range cmds {
var cmd *command = &cmds[i]
if commandCopyLen(cmd) != 0 && cmd.cmd_prefix_ >= 128 {
distance_prefixes[j] = cmd.dist_prefix_ & 0x3FF
j++
}
}
/* Create the block split on the array of distance prefixes. */
splitByteVectorDistance(distance_prefixes, j, kSymbolsPerDistanceHistogram, kMaxCommandHistograms, kCommandStrideLength, kDistanceBlockSwitchCost, params, dist_split)
distance_prefixes = nil
}
}