83 lines
2 KiB
Go
83 lines
2 KiB
Go
package hasher
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import (
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"hash"
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"unsafe"
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)
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type accurateRipDigestV1 struct {
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crc uint32
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pos uint32
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offset uint32
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}
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func NewAccurateRipV1(offset uint32) hash.Hash32 {
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return &accurateRipDigestV1{0, offset + 1, offset}
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}
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func (d *accurateRipDigestV1) Size() int { return 4 }
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func (d *accurateRipDigestV1) BlockSize() int { return 1 }
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func (d *accurateRipDigestV1) Reset() { d.crc = 0; d.pos = d.offset + 1 }
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func (d *accurateRipDigestV1) Sum32() uint32 { return d.crc }
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func (d *accurateRipDigestV1) Sum(in []byte) []byte {
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s := d.Sum32()
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return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s))
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}
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func (d *accurateRipDigestV1) Write(p []byte) (n int, err error) {
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numWords := uintptr(len(p)) * unsafe.Sizeof(p[0]) / unsafe.Sizeof(uint32(0))
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words := unsafe.Slice((*uint32)(unsafe.Pointer(unsafe.SliceData(p))), numWords)
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for _, w := range words {
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//this can wrap
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d.crc += d.pos * w
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d.pos++
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}
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return len(p), nil
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}
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type accurateRipDigestV2 struct {
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crc uint32
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multiplier uint32
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offset uint32
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}
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func NewAccurateRipV2(offset uint32) hash.Hash32 {
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return &accurateRipDigestV2{0, offset + 1, offset}
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}
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func (d *accurateRipDigestV2) Size() int { return 4 }
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func (d *accurateRipDigestV2) BlockSize() int { return 1 }
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func (d *accurateRipDigestV2) Reset() { d.crc = 0; d.multiplier = d.offset + 1 }
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func (d *accurateRipDigestV2) Sum32() uint32 { return d.crc }
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func (d *accurateRipDigestV2) Sum(in []byte) []byte {
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s := d.Sum32()
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return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s))
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}
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func (d *accurateRipDigestV2) Write(p []byte) (n int, err error) {
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numWords := uintptr(len(p)) * unsafe.Sizeof(p[0]) / unsafe.Sizeof(uint32(0))
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words := unsafe.Slice((*uint32)(unsafe.Pointer(unsafe.SliceData(p))), numWords)
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for _, w := range words {
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crcNew := uint64(w) * uint64(d.multiplier)
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LO := crcNew & 0xFFFFFFFF
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HI := crcNew / 0x100000000
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//this can wrap
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d.crc += uint32(HI)
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d.crc += uint32(LO)
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d.multiplier++
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}
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return len(p), nil
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}
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