feat: Waku v2 bridge

Issue #12610

vendor/github.com/ethereum/go-ethereum/common/hexutil/hexutil.go

@@ -0,0 +1,241 @@
+// Copyright 2016 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 hexutil implements hex encoding with 0x prefix.
+This encoding is used by the Ethereum RPC API to transport binary data in JSON payloads.
+
+# Encoding Rules
+
+All hex data must have prefix "0x".
+
+For byte slices, the hex data must be of even length. An empty byte slice
+encodes as "0x".
+
+Integers are encoded using the least amount of digits (no leading zero digits). Their
+encoding may be of uneven length. The number zero encodes as "0x0".
+*/
+package hexutil
+
+import (
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"strconv"
+)
+
+const uintBits = 32 << (uint64(^uint(0)) >> 63)
+
+// Errors
+var (
+	ErrEmptyString   = &decError{"empty hex string"}
+	ErrSyntax        = &decError{"invalid hex string"}
+	ErrMissingPrefix = &decError{"hex string without 0x prefix"}
+	ErrOddLength     = &decError{"hex string of odd length"}
+	ErrEmptyNumber   = &decError{"hex string \"0x\""}
+	ErrLeadingZero   = &decError{"hex number with leading zero digits"}
+	ErrUint64Range   = &decError{"hex number > 64 bits"}
+	ErrUintRange     = &decError{fmt.Sprintf("hex number > %d bits", uintBits)}
+	ErrBig256Range   = &decError{"hex number > 256 bits"}
+)
+
+type decError struct{ msg string }
+
+func (err decError) Error() string { return err.msg }
+
+// Decode decodes a hex string with 0x prefix.
+func Decode(input string) ([]byte, error) {
+	if len(input) == 0 {
+		return nil, ErrEmptyString
+	}
+	if !has0xPrefix(input) {
+		return nil, ErrMissingPrefix
+	}
+	b, err := hex.DecodeString(input[2:])
+	if err != nil {
+		err = mapError(err)
+	}
+	return b, err
+}
+
+// MustDecode decodes a hex string with 0x prefix. It panics for invalid input.
+func MustDecode(input string) []byte {
+	dec, err := Decode(input)
+	if err != nil {
+		panic(err)
+	}
+	return dec
+}
+
+// Encode encodes b as a hex string with 0x prefix.
+func Encode(b []byte) string {
+	enc := make([]byte, len(b)*2+2)
+	copy(enc, "0x")
+	hex.Encode(enc[2:], b)
+	return string(enc)
+}
+
+// DecodeUint64 decodes a hex string with 0x prefix as a quantity.
+func DecodeUint64(input string) (uint64, error) {
+	raw, err := checkNumber(input)
+	if err != nil {
+		return 0, err
+	}
+	dec, err := strconv.ParseUint(raw, 16, 64)
+	if err != nil {
+		err = mapError(err)
+	}
+	return dec, err
+}
+
+// MustDecodeUint64 decodes a hex string with 0x prefix as a quantity.
+// It panics for invalid input.
+func MustDecodeUint64(input string) uint64 {
+	dec, err := DecodeUint64(input)
+	if err != nil {
+		panic(err)
+	}
+	return dec
+}
+
+// EncodeUint64 encodes i as a hex string with 0x prefix.
+func EncodeUint64(i uint64) string {
+	enc := make([]byte, 2, 10)
+	copy(enc, "0x")
+	return string(strconv.AppendUint(enc, i, 16))
+}
+
+var bigWordNibbles int
+
+func init() {
+	// This is a weird way to compute the number of nibbles required for big.Word.
+	// The usual way would be to use constant arithmetic but go vet can't handle that.
+	b, _ := new(big.Int).SetString("FFFFFFFFFF", 16)
+	switch len(b.Bits()) {
+	case 1:
+		bigWordNibbles = 16
+	case 2:
+		bigWordNibbles = 8
+	default:
+		panic("weird big.Word size")
+	}
+}
+
+// DecodeBig decodes a hex string with 0x prefix as a quantity.
+// Numbers larger than 256 bits are not accepted.
+func DecodeBig(input string) (*big.Int, error) {
+	raw, err := checkNumber(input)
+	if err != nil {
+		return nil, err
+	}
+	if len(raw) > 64 {
+		return nil, ErrBig256Range
+	}
+	words := make([]big.Word, len(raw)/bigWordNibbles+1)
+	end := len(raw)
+	for i := range words {
+		start := end - bigWordNibbles
+		if start < 0 {
+			start = 0
+		}
+		for ri := start; ri < end; ri++ {
+			nib := decodeNibble(raw[ri])
+			if nib == badNibble {
+				return nil, ErrSyntax
+			}
+			words[i] *= 16
+			words[i] += big.Word(nib)
+		}
+		end = start
+	}
+	dec := new(big.Int).SetBits(words)
+	return dec, nil
+}
+
+// MustDecodeBig decodes a hex string with 0x prefix as a quantity.
+// It panics for invalid input.
+func MustDecodeBig(input string) *big.Int {
+	dec, err := DecodeBig(input)
+	if err != nil {
+		panic(err)
+	}
+	return dec
+}
+
+// EncodeBig encodes bigint as a hex string with 0x prefix.
+func EncodeBig(bigint *big.Int) string {
+	if sign := bigint.Sign(); sign == 0 {
+		return "0x0"
+	} else if sign > 0 {
+		return "0x" + bigint.Text(16)
+	} else {
+		return "-0x" + bigint.Text(16)[1:]
+	}
+}
+
+func has0xPrefix(input string) bool {
+	return len(input) >= 2 && input[0] == '0' && (input[1] == 'x' || input[1] == 'X')
+}
+
+func checkNumber(input string) (raw string, err error) {
+	if len(input) == 0 {
+		return "", ErrEmptyString
+	}
+	if !has0xPrefix(input) {
+		return "", ErrMissingPrefix
+	}
+	input = input[2:]
+	if len(input) == 0 {
+		return "", ErrEmptyNumber
+	}
+	if len(input) > 1 && input[0] == '0' {
+		return "", ErrLeadingZero
+	}
+	return input, nil
+}
+
+const badNibble = ^uint64(0)
+
+func decodeNibble(in byte) uint64 {
+	switch {
+	case in >= '0' && in <= '9':
+		return uint64(in - '0')
+	case in >= 'A' && in <= 'F':
+		return uint64(in - 'A' + 10)
+	case in >= 'a' && in <= 'f':
+		return uint64(in - 'a' + 10)
+	default:
+		return badNibble
+	}
+}
+
+func mapError(err error) error {
+	if err, ok := err.(*strconv.NumError); ok {
+		switch err.Err {
+		case strconv.ErrRange:
+			return ErrUint64Range
+		case strconv.ErrSyntax:
+			return ErrSyntax
+		}
+	}
+	if _, ok := err.(hex.InvalidByteError); ok {
+		return ErrSyntax
+	}
+	if err == hex.ErrLength {
+		return ErrOddLength
+	}
+	return err
+}