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12
13 package main
14
15 import (
16 "bytes"
17 "flag"
18 "go/format"
19 "log"
20 "os"
21 "strings"
22 "text/template"
23 )
24
25 var filename = flag.String("output", "md5block.go", "output file name")
26
27 func main() {
28 flag.Parse()
29
30 var buf bytes.Buffer
31
32 t := template.Must(template.New("main").Funcs(funcs).Parse(program))
33 if err := t.Execute(&buf, data); err != nil {
34 log.Fatal(err)
35 }
36
37 data, err := format.Source(buf.Bytes())
38 if err != nil {
39 log.Fatal(err)
40 }
41 err = os.WriteFile(*filename, data, 0644)
42 if err != nil {
43 log.Fatal(err)
44 }
45 }
46
47 type Data struct {
48 a, b, c, d string
49 Shift1 []int
50 Shift2 []int
51 Shift3 []int
52 Shift4 []int
53 Table1 []uint32
54 Table2 []uint32
55 Table3 []uint32
56 Table4 []uint32
57 }
58
59 var funcs = template.FuncMap{
60 "dup": dup,
61 "relabel": relabel,
62 "rotate": rotate,
63 "idx": idx,
64 "seq": seq,
65 }
66
67 func dup(count int, x []int) []int {
68 var out []int
69 for i := 0; i < count; i++ {
70 out = append(out, x...)
71 }
72 return out
73 }
74
75 func relabel(s string) string {
76 return strings.NewReplacer("arg0", data.a, "arg1", data.b, "arg2", data.c, "arg3", data.d).Replace(s)
77 }
78
79 func rotate() string {
80 data.a, data.b, data.c, data.d = data.d, data.a, data.b, data.c
81 return ""
82 }
83
84 func idx(round, index int) int {
85 v := 0
86 switch round {
87 case 1:
88 v = index
89 case 2:
90 v = (1 + 5*index) & 15
91 case 3:
92 v = (5 + 3*index) & 15
93 case 4:
94 v = (7 * index) & 15
95 }
96 return v
97 }
98
99 func seq(i int) []int {
100 s := make([]int, i)
101 for i := range s {
102 s[i] = i
103 }
104 return s
105 }
106
107 var data = Data{
108 a: "a",
109 b: "b",
110 c: "c",
111 d: "d",
112 Shift1: []int{7, 12, 17, 22},
113 Shift2: []int{5, 9, 14, 20},
114 Shift3: []int{4, 11, 16, 23},
115 Shift4: []int{6, 10, 15, 21},
116
117
118 Table1: []uint32{
119
120 0xd76aa478,
121 0xe8c7b756,
122 0x242070db,
123 0xc1bdceee,
124 0xf57c0faf,
125 0x4787c62a,
126 0xa8304613,
127 0xfd469501,
128 0x698098d8,
129 0x8b44f7af,
130 0xffff5bb1,
131 0x895cd7be,
132 0x6b901122,
133 0xfd987193,
134 0xa679438e,
135 0x49b40821,
136 },
137 Table2: []uint32{
138
139 0xf61e2562,
140 0xc040b340,
141 0x265e5a51,
142 0xe9b6c7aa,
143 0xd62f105d,
144 0x2441453,
145 0xd8a1e681,
146 0xe7d3fbc8,
147 0x21e1cde6,
148 0xc33707d6,
149 0xf4d50d87,
150 0x455a14ed,
151 0xa9e3e905,
152 0xfcefa3f8,
153 0x676f02d9,
154 0x8d2a4c8a,
155 },
156 Table3: []uint32{
157
158 0xfffa3942,
159 0x8771f681,
160 0x6d9d6122,
161 0xfde5380c,
162 0xa4beea44,
163 0x4bdecfa9,
164 0xf6bb4b60,
165 0xbebfbc70,
166 0x289b7ec6,
167 0xeaa127fa,
168 0xd4ef3085,
169 0x4881d05,
170 0xd9d4d039,
171 0xe6db99e5,
172 0x1fa27cf8,
173 0xc4ac5665,
174 },
175 Table4: []uint32{
176
177 0xf4292244,
178 0x432aff97,
179 0xab9423a7,
180 0xfc93a039,
181 0x655b59c3,
182 0x8f0ccc92,
183 0xffeff47d,
184 0x85845dd1,
185 0x6fa87e4f,
186 0xfe2ce6e0,
187 0xa3014314,
188 0x4e0811a1,
189 0xf7537e82,
190 0xbd3af235,
191 0x2ad7d2bb,
192 0xeb86d391,
193 },
194 }
195
196 var program = `// Copyright 2013 The Go Authors. All rights reserved.
197 // Use of this source code is governed by a BSD-style
198 // license that can be found in the LICENSE file.
199
200 // Code generated by go run gen.go -output md5block.go; DO NOT EDIT.
201
202 package md5
203
204 import (
205 "encoding/binary"
206 "math/bits"
207 )
208
209 func blockGeneric(dig *digest, p []byte) {
210 // load state
211 a, b, c, d := dig.s[0], dig.s[1], dig.s[2], dig.s[3]
212
213 for i := 0; i <= len(p)-BlockSize; i += BlockSize {
214 // eliminate bounds checks on p
215 q := p[i:]
216 q = q[:BlockSize:BlockSize]
217
218 // save current state
219 aa, bb, cc, dd := a, b, c, d
220
221 // load input block
222 {{range $i := seq 16 -}}
223 {{printf "x%x := binary.LittleEndian.Uint32(q[4*%#x:])" $i $i}}
224 {{end}}
225
226 // round 1
227 {{range $i, $s := dup 4 .Shift1 -}}
228 {{printf "arg0 = arg1 + bits.RotateLeft32((((arg2^arg3)&arg1)^arg3)+arg0+x%x+%#08x, %d)" (idx 1 $i) (index $.Table1 $i) $s | relabel}}
229 {{rotate -}}
230 {{end}}
231
232 // round 2
233 {{range $i, $s := dup 4 .Shift2 -}}
234 {{printf "arg0 = arg1 + bits.RotateLeft32((((arg1^arg2)&arg3)^arg2)+arg0+x%x+%#08x, %d)" (idx 2 $i) (index $.Table2 $i) $s | relabel}}
235 {{rotate -}}
236 {{end}}
237
238 // round 3
239 {{range $i, $s := dup 4 .Shift3 -}}
240 {{printf "arg0 = arg1 + bits.RotateLeft32((arg1^arg2^arg3)+arg0+x%x+%#08x, %d)" (idx 3 $i) (index $.Table3 $i) $s | relabel}}
241 {{rotate -}}
242 {{end}}
243
244 // round 4
245 {{range $i, $s := dup 4 .Shift4 -}}
246 {{printf "arg0 = arg1 + bits.RotateLeft32((arg2^(arg1|^arg3))+arg0+x%x+%#08x, %d)" (idx 4 $i) (index $.Table4 $i) $s | relabel}}
247 {{rotate -}}
248 {{end}}
249
250 // add saved state
251 a += aa
252 b += bb
253 c += cc
254 d += dd
255 }
256
257 // save state
258 dig.s[0], dig.s[1], dig.s[2], dig.s[3] = a, b, c, d
259 }
260 `
261
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