keccak/gen.go

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2015-01-01 00:40:56 +00:00
// +build ignore
package main
import (
"fmt"
"os"
"text/template"
)
var roundc [24]uint64
var rotc [5][5]int
func main() {
// Round constants
rc := uint8(1)
for i := 0; i < 24; i++ {
for j := 0; j <= 6; j++ {
roundc[i] |= uint64(rc&1) << (1<<uint(j) - 1)
rc = rc<<1 ^ 0x71&uint8(int8(rc)>>7)
}
}
// Rotation constants
x, y := 1, 0
for i := 1; i < 25; i++ {
rotc[x][y] = (i*(i+1)/2) % 64
x, y = y, (2*x+3*y)%5
}
var ctx = struct {
Rotc [5][5]int
} {
rotc,
}
err := tmpl.Execute(os.Stdout, &ctx)
if err != nil {
fmt.Println(err)
}
}
func count(n int) []int {
var out = make([]int, n)
for i := 0; i < n; i ++ {
out[i] = i
}
return out
}
func add(a, b, m int) int {
return (a+b) % m
}
func sub(a, b int) int {
return a - b
}
func mul(a, b int) int {
return a*b
}
var funcs = template.FuncMap{
"count": count,
"add": add,
"sub": sub,
"mul": mul,
}
var tmpl = template.Must(template.New("keccak").Funcs(funcs).Parse(`
// Generated from go run gen.go
// DO NOT EDIT
package keccak
// roundGeneric implements one round of the keccak-f[1600] permutation.
func roundGeneric(a *[5][5]uint64) {
{{ range $x := count 5 }}
{{ range $y := count 5 }}
var a{{$x}}{{$y}} = a[{{$y}}][{{$x}}]
{{ end }}
{{ end }}
// Theta
var c0, c1, c2, c3, c4 uint64
{{ range $x := count 5 }}
c{{$x}} = a{{$x}}0 ^ a{{$x}}1 ^ a{{$x}}2 ^ a{{$x}}3 ^ a{{$x}}4
{{ end }}
{{ range $x := count 5 }}
{{ $x0 := add $x 4 5 }}
{{ $x1 := add $x 1 5 }}
a{{$x}}0 ^= c{{$x0}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
a{{$x}}1 ^= c{{$x0}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
a{{$x}}2 ^= c{{$x0}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
a{{$x}}3 ^= c{{$x0}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
a{{$x}}4 ^= c{{$x0}} ^ (c{{$x1}}<<1 | c{{$x1}}>>63)
{{ end }}
// Rho and pi
{{ range $y := count 5 }}
{{ range $x := count 5 }}
{{ $x0 := $y }}
{{ $y0 := add (mul $x 2) (mul $y 3) 5 }}
{{ $r := index $.Rotc $x $y }}
var b{{$x0}}{{$y0}} = a{{$x}}{{$y}}<<{{$r}} | a{{$x}}{{$y}}>>{{sub 64 $r}}
{{ end }}
{{ end }}
// Chi
{{ range $y := count 5 }}
{{ range $x := count 5 }}
a{{$x}}{{$y}} = b{{$x}}{{$y}} ^ (b{{add $x 2 5}}{{$y}} &^ b{{add $x 1 5}}{{$y}})
{{ end }}
{{ end }}
// Output
{{ range $y := count 5 }}
{{ range $x := count 5 }}
a[{{$y}}][{{$x}}] = a{{$x}}{{$y}}
{{ end }}
{{ end }}
}
`))