/usr/share/gocode/src/github.com/pointlander/compress/arithmetic.go is in golang-github-pointlander-compress-dev 1.0.0-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | // 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
import "io"
func (model Model) Code(out io.Writer) {
var bits [1]byte
var mask uint8 = 0x80
output := func(bit uint16) {
if bit != 0 {
bits[0] |= mask
}
if mask >>= 1; mask == 0 {
out.Write(bits[:])
bits[0], mask = 0, 0x80
}
}
var low, high uint16 = 0, 0xffff
var underflow uint32
for current := range model.Input {
for _, s := range current {
hl, scale := uint32(high - low) + 1, uint32(s.Scale)
low, high = low + uint16((hl * uint32(s.Low)) / scale), low + uint16((hl * uint32(s.High)) / scale - 1)
for {
if low & 0x8000 == high & 0x8000 {
output(high & 0x8000)
for underflow > 0 {
output(^high & 0x8000)
underflow--
}
} else if low & 0x4000 != 0 && high & 0x4000 == 0 {
low, high, underflow = low & 0x3fff, high | 0x4000, underflow + 1
} else {
break
}
low, high = low << 1, (high << 1) | 1
}
}
}
output(low & 0x4000)
underflow++
for underflow > 0 {
output(^low & 0x4000)
underflow--
}
if mask != 0x80 {
out.Write(bits[:])
}
}
func (model Model) Decode(in io.Reader) {
var bits [1]byte
var mask uint8 = 0x80
var code uint16
input := func() {
if code <<= 1; bits[0] & mask != 0 {
code |= 1
}
if mask >>= 1; mask == 0 {
if n, _ := in.Read(bits[:]); n > 0 {
mask = 0x80
}
}
}
in.Read(bits[:])
for i := 0; i < 16; i++ {
input()
}
var low, high uint16 = 0, 0xffff
hl := uint32(high - low) + 1
s := model.Output(uint16(((uint32(code - low) + 1) * model.Scale - 1) / hl))
for s.High != 0 {
low, high = low + uint16((hl * uint32(s.Low)) / model.Scale), low + uint16((hl * uint32(s.High)) / model.Scale - 1)
for {
if low & 0x8000 == high & 0x8000 {
} else if low & 0x4000 != 0 && high & 0x4000 == 0 {
low, high, code = low & 0x3fff, high | 0x4000, code ^ 0x4000
} else {
hl, model.Scale = uint32(high - low) + 1, uint32(s.Scale)
break
}
input()
low, high = low << 1, (high << 1) | 1
}
s = model.Output(uint16(((uint32(code - low) + 1) * model.Scale - 1) / hl))
}
}
func (model Model32) Code(out io.Writer) {
var bits [1]byte
var mask uint8 = 0x80
output := func(bit uint32) {
if bit != 0 {
bits[0] |= mask
}
if mask >>= 1; mask == 0 {
out.Write(bits[:])
bits[0], mask = 0, 0x80
}
}
var low, high uint32 = 0, 0xffffffff
var underflow uint32
for current := range model.Input {
for _, s := range current {
hl, scale := uint64(high - low) + 1, uint64(s.Scale)
low, high = low + uint32((hl * uint64(s.Low)) / scale), low + uint32((hl * uint64(s.High)) / scale - 1)
for {
if low & 0x80000000 == high & 0x80000000 {
output(high & 0x80000000)
for underflow > 0 {
output(^high & 0x80000000)
underflow--
}
} else if low & 0x40000000 != 0 && high & 0x40000000 == 0 {
low, high, underflow = low & 0x3fffffff, high | 0x40000000, underflow + 1
} else {
break
}
low, high = low << 1, (high << 1) | 1
}
}
}
output(low & 0x40000000)
underflow++
for underflow > 0 {
output(^low & 0x40000000)
underflow--
}
if mask != 0x80 {
out.Write(bits[:])
}
}
func (model Model32) Decode(in io.Reader) {
var bits [1]byte
var mask uint8 = 0x80
var code uint32
input := func() {
if code <<= 1; bits[0] & mask != 0 {
code |= 1
}
if mask >>= 1; mask == 0 {
if n, _ := in.Read(bits[:]); n > 0 {
mask = 0x80
}
}
}
in.Read(bits[:])
for i := 0; i < 32; i++ {
input()
}
var low, high uint32 = 0, 0xffffffff
hl := uint64(high - low) + 1
s := model.Output(uint32(((uint64(code - low) + 1) * model.Scale - 1) / hl))
for s.High != 0 {
low, high = low + uint32((hl * uint64(s.Low)) / model.Scale), low + uint32((hl * uint64(s.High)) / model.Scale - 1)
for {
if low & 0x80000000 == high & 0x80000000 {
} else if low & 0x40000000 != 0 && high & 0x40000000 == 0 {
low, high, code = low & 0x3fffffff, high | 0x40000000, code ^ 0x40000000
} else {
hl, model.Scale = uint64(high - low) + 1, uint64(s.Scale)
break
}
input()
low, high = low << 1, (high << 1) | 1
}
s = model.Output(uint32(((uint64(code - low) + 1) * model.Scale - 1) / hl))
}
}
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