mirror of https://github.com/ethereum/go-ethereum
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
81 lines
2.1 KiB
81 lines
2.1 KiB
// Copyright 2023 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 internal
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
|
|
"github.com/holiman/uint256"
|
|
)
|
|
|
|
const (
|
|
memoryPadLimit = 1024 * 1024
|
|
)
|
|
|
|
// GetMemoryCopyPadded returns offset + size as a new slice.
|
|
// It zero-pads the slice if it extends beyond memory bounds.
|
|
func GetMemoryCopyPadded(m []byte, offset, size int64) ([]byte, error) {
|
|
if offset < 0 || size < 0 {
|
|
return nil, errors.New("offset or size must not be negative")
|
|
}
|
|
length := int64(len(m))
|
|
if offset+size < length { // slice fully inside memory
|
|
return memoryCopy(m, offset, size), nil
|
|
}
|
|
paddingNeeded := offset + size - length
|
|
if paddingNeeded > memoryPadLimit {
|
|
return nil, fmt.Errorf("reached limit for padding memory slice: %d", paddingNeeded)
|
|
}
|
|
cpy := make([]byte, size)
|
|
if overlap := length - offset; overlap > 0 {
|
|
copy(cpy, MemoryPtr(m, offset, overlap))
|
|
}
|
|
return cpy, nil
|
|
}
|
|
|
|
func memoryCopy(m []byte, offset, size int64) (cpy []byte) {
|
|
if size == 0 {
|
|
return nil
|
|
}
|
|
|
|
if len(m) > int(offset) {
|
|
cpy = make([]byte, size)
|
|
copy(cpy, m[offset:offset+size])
|
|
|
|
return
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// MemoryPtr returns a pointer to a slice of memory.
|
|
func MemoryPtr(m []byte, offset, size int64) []byte {
|
|
if size == 0 {
|
|
return nil
|
|
}
|
|
|
|
if len(m) > int(offset) {
|
|
return m[offset : offset+size]
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// StackBack returns the n'th item in stack
|
|
func StackBack(st []uint256.Int, n int) *uint256.Int {
|
|
return &st[len(st)-n-1]
|
|
}
|
|
|