github.com/MikyChow/arbitrum-go-ethereum@v0.0.0-20230306102812-078da49636de/common/bytes.go (about)

     1  // Copyright 2014 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  // Package common contains various helper functions.
    18  package common
    19  
    20  import (
    21  	"encoding/hex"
    22  	"errors"
    23  
    24  	"github.com/MikyChow/arbitrum-go-ethereum/common/hexutil"
    25  )
    26  
    27  // FromHex returns the bytes represented by the hexadecimal string s.
    28  // s may be prefixed with "0x".
    29  func FromHex(s string) []byte {
    30  	if has0xPrefix(s) {
    31  		s = s[2:]
    32  	}
    33  	if len(s)%2 == 1 {
    34  		s = "0" + s
    35  	}
    36  	return Hex2Bytes(s)
    37  }
    38  
    39  // CopyBytes returns an exact copy of the provided bytes.
    40  func CopyBytes(b []byte) (copiedBytes []byte) {
    41  	if b == nil {
    42  		return nil
    43  	}
    44  	copiedBytes = make([]byte, len(b))
    45  	copy(copiedBytes, b)
    46  
    47  	return
    48  }
    49  
    50  // has0xPrefix validates str begins with '0x' or '0X'.
    51  func has0xPrefix(str string) bool {
    52  	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
    53  }
    54  
    55  // isHexCharacter returns bool of c being a valid hexadecimal.
    56  func isHexCharacter(c byte) bool {
    57  	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
    58  }
    59  
    60  // isHex validates whether each byte is valid hexadecimal string.
    61  func isHex(str string) bool {
    62  	if len(str)%2 != 0 {
    63  		return false
    64  	}
    65  	for _, c := range []byte(str) {
    66  		if !isHexCharacter(c) {
    67  			return false
    68  		}
    69  	}
    70  	return true
    71  }
    72  
    73  // Bytes2Hex returns the hexadecimal encoding of d.
    74  func Bytes2Hex(d []byte) string {
    75  	return hex.EncodeToString(d)
    76  }
    77  
    78  // Hex2Bytes returns the bytes represented by the hexadecimal string str.
    79  func Hex2Bytes(str string) []byte {
    80  	h, _ := hex.DecodeString(str)
    81  	return h
    82  }
    83  
    84  // Hex2BytesFixed returns bytes of a specified fixed length flen.
    85  func Hex2BytesFixed(str string, flen int) []byte {
    86  	h, _ := hex.DecodeString(str)
    87  	if len(h) == flen {
    88  		return h
    89  	}
    90  	if len(h) > flen {
    91  		return h[len(h)-flen:]
    92  	}
    93  	hh := make([]byte, flen)
    94  	copy(hh[flen-len(h):flen], h)
    95  	return hh
    96  }
    97  
    98  // ParseHexOrString tries to hexdecode b, but if the prefix is missing, it instead just returns the raw bytes
    99  func ParseHexOrString(str string) ([]byte, error) {
   100  	b, err := hexutil.Decode(str)
   101  	if errors.Is(err, hexutil.ErrMissingPrefix) {
   102  		return []byte(str), nil
   103  	}
   104  	return b, err
   105  }
   106  
   107  // RightPadBytes zero-pads slice to the right up to length l.
   108  func RightPadBytes(slice []byte, l int) []byte {
   109  	if l <= len(slice) {
   110  		return slice
   111  	}
   112  
   113  	padded := make([]byte, l)
   114  	copy(padded, slice)
   115  
   116  	return padded
   117  }
   118  
   119  // LeftPadBytes zero-pads slice to the left up to length l.
   120  func LeftPadBytes(slice []byte, l int) []byte {
   121  	if l <= len(slice) {
   122  		return slice
   123  	}
   124  
   125  	padded := make([]byte, l)
   126  	copy(padded[l-len(slice):], slice)
   127  
   128  	return padded
   129  }
   130  
   131  // TrimLeftZeroes returns a subslice of s without leading zeroes
   132  func TrimLeftZeroes(s []byte) []byte {
   133  	idx := 0
   134  	for ; idx < len(s); idx++ {
   135  		if s[idx] != 0 {
   136  			break
   137  		}
   138  	}
   139  	return s[idx:]
   140  }
   141  
   142  // TrimRightZeroes returns a subslice of s without trailing zeroes
   143  func TrimRightZeroes(s []byte) []byte {
   144  	idx := len(s)
   145  	for ; idx > 0; idx-- {
   146  		if s[idx-1] != 0 {
   147  			break
   148  		}
   149  	}
   150  	return s[:idx]
   151  }