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unroll word<->byte conversions

This commit is contained in:
lukechampine 2020-01-13 14:27:21 -05:00
parent f87940e245
commit 20804e899d
1 changed files with 47 additions and 16 deletions
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63
blake3.go
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@ -33,16 +33,42 @@ var iv = [8]uint32{
// helper functions for converting between bytes and BLAKE3 "words"
func bytesToWords(bytes []byte, words []uint32) {
for i := range words {
words[i] = binary.LittleEndian.Uint32(bytes[i*4:])
}
func bytesToWords(bytes [64]byte, words *[16]uint32) {
words[0] = binary.LittleEndian.Uint32(bytes[0:])
words[1] = binary.LittleEndian.Uint32(bytes[4:])
words[2] = binary.LittleEndian.Uint32(bytes[8:])
words[3] = binary.LittleEndian.Uint32(bytes[12:])
words[4] = binary.LittleEndian.Uint32(bytes[16:])
words[5] = binary.LittleEndian.Uint32(bytes[20:])
words[6] = binary.LittleEndian.Uint32(bytes[24:])
words[7] = binary.LittleEndian.Uint32(bytes[28:])
words[8] = binary.LittleEndian.Uint32(bytes[32:])
words[9] = binary.LittleEndian.Uint32(bytes[36:])
words[10] = binary.LittleEndian.Uint32(bytes[40:])
words[11] = binary.LittleEndian.Uint32(bytes[44:])
words[12] = binary.LittleEndian.Uint32(bytes[48:])
words[13] = binary.LittleEndian.Uint32(bytes[52:])
words[14] = binary.LittleEndian.Uint32(bytes[56:])
words[15] = binary.LittleEndian.Uint32(bytes[60:])
}
func wordsToBytes(words []uint32, bytes []byte) {
for i, w := range words {
binary.LittleEndian.PutUint32(bytes[i*4:], w)
}
func wordsToBytes(words [16]uint32, block *[64]byte) {
binary.LittleEndian.PutUint32(block[0:], words[0])
binary.LittleEndian.PutUint32(block[4:], words[1])
binary.LittleEndian.PutUint32(block[8:], words[2])
binary.LittleEndian.PutUint32(block[12:], words[3])
binary.LittleEndian.PutUint32(block[16:], words[4])
binary.LittleEndian.PutUint32(block[20:], words[5])
binary.LittleEndian.PutUint32(block[24:], words[6])
binary.LittleEndian.PutUint32(block[28:], words[7])
binary.LittleEndian.PutUint32(block[32:], words[8])
binary.LittleEndian.PutUint32(block[36:], words[9])
binary.LittleEndian.PutUint32(block[40:], words[10])
binary.LittleEndian.PutUint32(block[44:], words[11])
binary.LittleEndian.PutUint32(block[48:], words[12])
binary.LittleEndian.PutUint32(block[52:], words[13])
binary.LittleEndian.PutUint32(block[56:], words[14])
binary.LittleEndian.PutUint32(block[60:], words[15])
}
func g(a, b, c, d, mx, my uint32) (uint32, uint32, uint32, uint32) {
@ -199,7 +225,7 @@ func (cs *chunkState) update(input []byte) {
// input is coming, so this compression is not flagChunkEnd.
if cs.blockLen == blockSize {
// copy the chunk block (bytes) into the node block and chain it.
bytesToWords(cs.block[:], cs.n.block[:])
bytesToWords(cs.block, &cs.n.block)
cs.n.cv = cs.n.chainingValue()
// clear the start flag for all but the first block
cs.n.flags &^= flagChunkStart
@ -227,7 +253,7 @@ func (cs *chunkState) node() node {
n := cs.n
// pad the remaining space in the block with zeros
clear(cs.block[cs.blockLen:])
bytesToWords(cs.block[:], n.block[:])
bytesToWords(cs.block, &n.block)
n.blockLen = uint32(cs.blockLen)
n.flags |= flagChunkEnd
return n
@ -374,7 +400,9 @@ func New(size int, key []byte) *Hasher {
return newHasher(iv, 0, size)
}
var keyWords [8]uint32
bytesToWords(key[:], keyWords[:])
for i := range keyWords {
keyWords[i] = binary.LittleEndian.Uint32(key[i*4:])
}
return newHasher(keyWords, flagKeyedHash, size)
}
@ -410,9 +438,12 @@ func DeriveKey(subKey []byte, ctx string, srcKey []byte) {
const derivationIVLen = 32
h := newHasher(iv, flagDeriveKeyContext, 32)
h.Write([]byte(ctx))
var derivationIV [8]uint32
bytesToWords(h.Sum(make([]byte, 0, derivationIVLen)), derivationIV[:])
h = newHasher(derivationIV, flagDeriveKeyMaterial, 0)
derivationIV := h.Sum(make([]byte, 0, derivationIVLen))
var ivWords [8]uint32
for i := range ivWords {
ivWords[i] = binary.LittleEndian.Uint32(derivationIV[i*4:])
}
h = newHasher(ivWords, flagDeriveKeyMaterial, 0)
// derive the subKey
h.Write(srcKey)
h.XOF().Read(subKey)
@ -439,7 +470,7 @@ func (or *OutputReader) Read(p []byte) (int, error) {
if or.off%blockSize == 0 {
or.n.counter = or.off / blockSize
words := or.n.compress()
wordsToBytes(words[:], or.block[:])
wordsToBytes(words, &or.block)
}
n := copy(p, or.block[or.off%blockSize:])
@ -476,7 +507,7 @@ func (or *OutputReader) Seek(offset int64, whence int) (int64, error) {
or.n.counter = uint64(off) / blockSize
if or.off%blockSize != 0 {
words := or.n.compress()
wordsToBytes(words[:], or.block[:])
wordsToBytes(words, &or.block)
}
// NOTE: or.off >= 2^63 will result in a negative return value.
// Nothing we can do about this.