github.com/annchain/OG@v0.0.9/common/bytes.go

// 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 common contains various helper functions.
package common

import (
	"encoding/hex"
	"github.com/annchain/OG/arefactor/common/utilfuncs"
)

// ToHex returns the hex representation of b, prefixed with '0x'.
// For empty slices, the return value is "0x0".
//
// Deprecated: use hexutil.Encode instead.
func ToHex(b []byte) string {
	hexstr := Bytes2Hex(b)
	if len(hexstr) == 0 {
		hexstr = "0"
	}
	return "0x" + hexstr
}

// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) ([]byte, error) {
	if len(s) > 1 {
		if s[0:2] == "0x" || s[0:2] == "0X" {
			s = s[2:]
		}
	}
	if len(s)%2 == 1 {
		s = "0" + s
	}
	return Hex2Bytes(s)
}

// CopyBytes returns an exact copy of the provided bytes.
func CopyBytes(b []byte) (copiedBytes []byte) {
	if b == nil {
		return nil
	}
	copiedBytes = make([]byte, len(b))
	copy(copiedBytes, b)

	return
}

// hasHexPrefix validates str begins with '0x' or '0X'.
func hasHexPrefix(str string) bool {
	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}

// isHexCharacter returns bool of c being a valid hexadecimal.
func isHexCharacter(c byte) bool {
	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}

// isHex validates whether each byte is valid hexadecimal string.
func isHex(str string) bool {
	if len(str)%2 != 0 {
		return false
	}
	for _, c := range []byte(str) {
		if !isHexCharacter(c) {
			return false
		}
	}
	return true
}

// Bytes2Hex returns the hexadecimal encoding of d.
func Bytes2Hex(d []byte) string {
	return hex.EncodeToString(d)
}

// Hex2Bytes returns the bytes represented by the hexadecimal string str.
func Hex2Bytes(str string) ([]byte, error) {
	h, err := hex.DecodeString(str)
	return h, err
}

// Hex2BytesNoError panics if hex is wrong. Use it ONLY in test code
func Hex2BytesNoError(str string) []byte {
	h, err := Hex2Bytes(str)
	utilfuncs.PanicIfError(err, "hex2bytes")
	return h
}

// Hex2BytesFixed returns bytes of a specified fixed length flen.
func Hex2BytesFixed(str string, flen int) []byte {
	h, _ := hex.DecodeString(str)
	if len(h) == flen {
		return h
	}
	if len(h) > flen {
		return h[len(h)-flen:]
	}
	hh := make([]byte, flen)
	copy(hh[flen-len(h):flen], h[:])
	return hh
}

// RightPadBytes zero-pads slice to the right up to length l.
func RightPadBytes(slice []byte, l int) []byte {
	if l <= len(slice) {
		return slice
	}

	padded := make([]byte, l)
	copy(padded, slice)

	return padded
}

// LeftPadBytes zero-pads slice to the left up to length l.
func LeftPadBytes(slice []byte, l int) []byte {
	if l <= len(slice) {
		return slice
	}

	padded := make([]byte, l)
	copy(padded[l-len(slice):], slice)

	return padded
}

// IsSameBytes compares two byte slice. Return true if they are the
// same, otherwise false.
func IsSameBytes(s, t []byte) bool {
	if (s == nil) != (t == nil) {
		return false
	}
	if len(s) != len(t) {
		return false
	}
	for i := range s {
		if s[i] != t[i] {
			return false
		}
	}
	return true
}

// GetInt32 get an int32 from byte array with a start position.
func GetInt32(b []byte, pos int) int32 {
	return int32(b[pos]) | int32(b[pos+1])<<8 | int32(b[pos+2])<<16 | int32(b[pos+3])<<24
}

// SetInt32 set an int32 into byte array at a position.
func SetInt32(b []byte, pos int, i int32) {
	b[pos] = byte(i)
	b[pos+1] = byte(i >> 8)
	b[pos+2] = byte(i >> 16)
	b[pos+3] = byte(i >> 24)
}

// ByteInt32 convert an int32 to byte array.
func ByteInt32(i int32) []byte {
	b := make([]byte, 4)

	b[0] = byte(i)
	b[1] = byte(i >> 8)
	b[2] = byte(i >> 16)
	b[3] = byte(i >> 24)

	return b
}