/
blake2f.go
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/
blake2f.go
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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package precompile
import (
"encoding/binary"
"errors"
"github.com/thu-arxan/evm/crypto/blake2b"
)
type blake2F struct{}
func (c *blake2F) RequiredGas(input []byte) uint64 {
// If the input is malformed, we can't calculate the gas, return 0 and let the
// actual call choke and fault.
if len(input) != blake2FInputLength {
return 0
}
return uint64(binary.BigEndian.Uint32(input[0:4]))
}
const (
blake2FInputLength = 213
blake2FFinalBlockBytes = byte(1)
blake2FNonFinalBlockBytes = byte(0)
)
var (
errBlake2FInvalidInputLength = errors.New("invalid input length")
errBlake2FInvalidFinalFlag = errors.New("invalid final flag")
)
func (c *blake2F) Run(input []byte) ([]byte, error) {
// Make sure the input is valid (correct lenth and final flag)
if len(input) != blake2FInputLength {
return nil, errBlake2FInvalidInputLength
}
if input[212] != blake2FNonFinalBlockBytes && input[212] != blake2FFinalBlockBytes {
return nil, errBlake2FInvalidFinalFlag
}
// Parse the input into the Blake2b call parameters
var (
rounds = binary.BigEndian.Uint32(input[0:4])
final = (input[212] == blake2FFinalBlockBytes)
h [8]uint64
m [16]uint64
t [2]uint64
)
for i := 0; i < 8; i++ {
offset := 4 + i*8
h[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
}
for i := 0; i < 16; i++ {
offset := 68 + i*8
m[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
}
t[0] = binary.LittleEndian.Uint64(input[196:204])
t[1] = binary.LittleEndian.Uint64(input[204:212])
// Execute the compression function, extract and return the result
blake2b.F(&h, m, t, final, rounds)
output := make([]byte, 64)
for i := 0; i < 8; i++ {
offset := i * 8
binary.LittleEndian.PutUint64(output[offset:offset+8], h[i])
}
return output, nil
}