/usr/share/gocode/src/github.com/pointlander/compress/move_to_front.go is in golang-github-pointlander-compress-dev 1.1.0-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | // Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package compress
func (coder Coder8) MoveToFrontCoder() Coder16 {
symbols := make(chan []uint16, BUFFER_CHAN_SIZE)
go func() {
nodes, buffer := [256]byte{}, [BUFFER_POOL_SIZE]uint16{}
var first byte
for node, _ := range nodes {
nodes[node] = uint8(node) + 1
}
current, offset, index := buffer[0:BUFFER_SIZE], BUFFER_SIZE, 0
for block := range coder.Input {
for _, v := range block {
var node, next byte
var symbol uint16
for next = first; next != v; node, next = next, nodes[next] {
symbol++
}
current[index], index = symbol, index + 1
if symbol != 0 {
first, nodes[node], nodes[next] = next, nodes[next], first
}
if index == BUFFER_SIZE {
symbols <- current
next := offset + BUFFER_SIZE
current, offset, index = buffer[offset:next], next & BUFFER_POOL_SIZE_MASK, 0
}
}
}
symbols <- current[:index]
close(symbols)
}()
return Coder16{Alphabit:256, Input:symbols}
}
func (coder Coder8) MoveToFrontDecoder() Coder16 {
nodes := [256]byte{}
var first byte
for node, _ := range nodes {
nodes[node] = uint8(node) + 1
}
output := func(symbol uint16) bool {
var node, next byte
moveToFront := symbol != 0
for next = first; symbol > 0; node, next = next, nodes[next] {
symbol--
}
if moveToFront {
first, nodes[node], nodes[next] = next, nodes[next], first
}
return coder.Output(next)
}
return Coder16{Alphabit:256, Output:output}
}
func (coder Coder8) MoveToFrontRunLengthCoder() Coder16 {
symbols := make(chan []uint16, BUFFER_CHAN_SIZE)
go func() {
var buffer [BUFFER_POOL_SIZE]uint16
current, offset, index, length := buffer[0:BUFFER_SIZE], BUFFER_SIZE, 0, uint64(0)
outputSymbol := func(symbol uint16) {
current[index], index = symbol, index + 1
if index == BUFFER_SIZE {
symbols <- current
next := offset + BUFFER_SIZE
current, offset, index = buffer[offset:next], next & BUFFER_POOL_SIZE_MASK, 0
}
}
outputLength := func() {
if length > 0 {
length--
outputSymbol(uint16(length & 1))
for length > 1 {
length = (length - 2) >> 1
outputSymbol(uint16(length & 1))
}
length = 0
}
}
var nodes [256]byte
var first byte
for node, _ := range nodes {
nodes[node] = byte(node) + 1
}
for block := range coder.Input {
for _, v := range block {
var node, next byte
var symbol uint16
for next = first; next != v; node, next = next, nodes[next] {
symbol++
}
if symbol == 0 {
length++
continue
}
first, nodes[node], nodes[next] = next, nodes[next], first
outputLength()
outputSymbol(symbol + 1)
}
}
outputLength()
symbols <- current[:index]
close(symbols)
}()
return Coder16{Alphabit:257, Input:symbols}
}
func (coder Coder8) MoveToFrontRunLengthDecoder() Coder16 {
var nodes [256]byte
var first byte
for node, _ := range nodes {
nodes[node] = uint8(node) + 1
}
length := uint64(1)
output := func(symbol uint16) bool {
if symbol > 1 {
var node, next byte
symbol, length = symbol - 1, 1
for next = first; symbol > 0; node, next = next, nodes[next] {
symbol--
}
first, nodes[node], nodes[next] = next, nodes[next], first
return coder.Output(next)
}
for c := length << symbol; c > 0; c-- {
if coder.Output(first) {
return true
}
}
length <<= 1
return false
}
return Coder16{Alphabit:257, Output:output}
}
|