forked from TrueCloudLab/tzhash
55 lines
1.4 KiB
Go
55 lines
1.4 KiB
Go
package tz
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import (
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"hash"
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"github.com/nspcc-dev/tzhash/gf127"
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)
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type digest2 struct {
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x [2]gf127.GF127x2
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}
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var _ hash.Hash = (*digest2)(nil)
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func (d *digest2) Write(data []byte) (n int, err error) {
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n = len(data)
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for _, b := range data {
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>7)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>6)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>5)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>4)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>3)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>2)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>1)&1])
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mulBitRightx2(&d.x[0], &d.x[1], &minmax[(b>>0)&1])
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}
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return
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}
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func (d *digest2) Sum(in []byte) []byte {
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// Make a copy of d so that caller can keep writing and summing.
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d0 := *d
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h := d0.checkSum()
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return append(in, h[:]...)
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}
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func (d *digest2) Reset() {
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d.x[0] = gf127.GF127x2{1, 0, 0, 0}
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d.x[1] = gf127.GF127x2{0, 0, 1, 0}
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}
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func (d *digest2) Size() int { return hashSize }
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func (d *digest2) BlockSize() int { return hashBlockSize }
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func (d *digest2) checkSum() (b [hashSize]byte) {
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// Matrix is stored transposed,
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// but we need to use order consistent with digest.
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h := d.x[0].ByteArray()
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copy(b[:], h[:16])
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copy(b[32:], h[16:])
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h = d.x[1].ByteArray()
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copy(b[16:], h[:16])
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copy(b[48:], h[16:])
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return
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}
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func mulBitRightx2(c00c10 *gf127.GF127x2, c01c11 *gf127.GF127x2, e *gf127.GF127)
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