forked from cerc-io/plugeth
84f8c0cc1f
This commit adds many comments and removes unused code. It also removes the EmptyHash function, which had some uses but was silly.
130 lines
3.2 KiB
Go
130 lines
3.2 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package common contains various helper functions.
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package common
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import "encoding/hex"
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// ToHex returns the hex representation of b, prefixed with '0x'.
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// For empty slices, the return value is "0x0".
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//
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// Deprecated: use hexutil.Encode instead.
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func ToHex(b []byte) string {
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hex := Bytes2Hex(b)
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if len(hex) == 0 {
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hex = "0"
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}
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return "0x" + hex
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}
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// FromHex returns the bytes represented by the hexadecimal string s.
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// s may be prefixed with "0x".
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func FromHex(s string) []byte {
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if len(s) > 1 {
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if s[0:2] == "0x" || s[0:2] == "0X" {
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s = s[2:]
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}
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}
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if len(s)%2 == 1 {
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s = "0" + s
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}
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return Hex2Bytes(s)
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}
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// CopyBytes returns an exact copy of the provided bytes.
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func CopyBytes(b []byte) (copiedBytes []byte) {
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if b == nil {
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return nil
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}
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copiedBytes = make([]byte, len(b))
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copy(copiedBytes, b)
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return
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}
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// hasHexPrefix validates str begins with '0x' or '0X'.
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func hasHexPrefix(str string) bool {
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return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
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}
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// isHexCharacter returns bool of c being a valid hexadecimal.
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func isHexCharacter(c byte) bool {
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return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
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}
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// isHex validates whether each byte is valid hexadecimal string.
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func isHex(str string) bool {
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if len(str)%2 != 0 {
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return false
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}
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for _, c := range []byte(str) {
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if !isHexCharacter(c) {
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return false
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}
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}
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return true
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}
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// Bytes2Hex returns the hexadecimal encoding of d.
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func Bytes2Hex(d []byte) string {
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return hex.EncodeToString(d)
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}
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// Hex2Bytes returns the bytes represented by the hexadecimal string str.
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func Hex2Bytes(str string) []byte {
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h, _ := hex.DecodeString(str)
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return h
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}
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// Hex2BytesFixed returns bytes of a specified fixed length flen.
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func Hex2BytesFixed(str string, flen int) []byte {
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h, _ := hex.DecodeString(str)
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if len(h) == flen {
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return h
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}
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if len(h) > flen {
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return h[len(h)-flen:]
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}
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hh := make([]byte, flen)
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copy(hh[flen-len(h):flen], h[:])
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return hh
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}
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// RightPadBytes zero-pads slice to the right up to length l.
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func RightPadBytes(slice []byte, l int) []byte {
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if l <= len(slice) {
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return slice
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}
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padded := make([]byte, l)
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copy(padded, slice)
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return padded
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}
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// LeftPadBytes zero-pads slice to the left up to length l.
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func LeftPadBytes(slice []byte, l int) []byte {
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if l <= len(slice) {
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return slice
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}
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padded := make([]byte, l)
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copy(padded[l-len(slice):], slice)
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return padded
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}
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