/
sha256.go
37 lines (33 loc) · 1.23 KB
/
sha256.go
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/*
* Copyright 2020 The SealEVM Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package precompiledContracts
import (
"crypto/sha256"
"github.com/ethereum/go-ethereum/params"
)
// SHA256 implemented as a native contract.
type sha256hash struct{}
// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *sha256hash) GasCost(input []byte) uint64 {
return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas
}
func (c *sha256hash) Execute(input []byte) ([]byte, error) {
h := sha256.Sum256(input)
return h[:], nil
}