crypto/common/types.go

// Copyright 2025 The Lux Authors
// This file is part of the Lux library.
//
// The Lux 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 Lux 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 Lux library. If not, see <http://www.gnu.org/licenses/>.

package common

import (
	"bytes"
	"database/sql/driver"
	"encoding/hex"
	"fmt"
	"math/big"
	"math/rand"

	"golang.org/x/crypto/sha3"
)

const (
	// HashLength is the expected length of the hash
	HashLength = 32
	// AddressLength is the expected length of the address
	AddressLength = 20
)

// Common big integers often used
var (
	Big0   = big.NewInt(0)
	Big1   = big.NewInt(1)
	Big2   = big.NewInt(2)
	Big3   = big.NewInt(3)
	Big256 = big.NewInt(256)
	Big257 = big.NewInt(257)
)

// Hash represents the 32 byte Keccak256 hash of arbitrary data.
type Hash [HashLength]byte

// BytesToHash sets b to hash.
// If b is larger than len(h), b will be cropped from the left.
func BytesToHash(b []byte) Hash {
	var h Hash
	h.SetBytes(b)
	return h
}

// BigToHash sets byte representation of b to hash.
// If b is larger than len(h), b will be cropped from the left.
func BigToHash(b *big.Int) Hash { return BytesToHash(b.Bytes()) }

// HexToHash sets byte representation of s to hash.
// If b is larger than len(h), b will be cropped from the left.
func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }

// Bytes gets the byte representation of the underlying hash.
func (h Hash) Bytes() []byte { return h[:] }

// Big converts a hash to a big integer.
func (h Hash) Big() *big.Int { return new(big.Int).SetBytes(h[:]) }

// Hex converts a hash to a hex string.
func (h Hash) Hex() string { return hexEncodeToString(h[:]) }

// String implements the stringer interface and is used also by the logger when
// doing full logging into a file.
func (h Hash) String() string {
	return h.Hex()
}

// SetBytes sets the hash to the value of b.
// If b is larger than len(h), b will be cropped from the left.
func (h *Hash) SetBytes(b []byte) {
	if len(b) > len(h) {
		b = b[len(b)-HashLength:]
	}

	copy(h[HashLength-len(b):], b)
}

// Generate implements testing/quick.Generator.
func (h Hash) Generate(rand *rand.Rand, size int) interface{} {
	m := rand.Intn(len(h))
	for i := len(h) - 1; i > m; i-- {
		h[i] = byte(rand.Uint32())
	}
	return h
}

// Scan implements Scanner for database/sql.
func (h *Hash) Scan(src interface{}) error {
	srcB, ok := src.([]byte)
	if !ok {
		return fmt.Errorf("can't scan %T into Hash", src)
	}
	if len(srcB) != HashLength {
		return fmt.Errorf("can't scan []byte of len %d into Hash, want %d", len(srcB), HashLength)
	}
	copy(h[:], srcB)
	return nil
}

// Value implements valuer for database/sql.
func (h Hash) Value() (driver.Value, error) {
	return h[:], nil
}

// UnmarshalText parses a hash in hex syntax.
func (h *Hash) UnmarshalText(input []byte) error {
	return hexDecode(h[:], input)
}

// UnmarshalJSON parses a hash in hex syntax.
func (h *Hash) UnmarshalJSON(input []byte) error {
	return hexDecode(h[:], input)
}

// MarshalText returns the hex representation of h.
func (h Hash) MarshalText() ([]byte, error) {
	return hexEncode(h[:]), nil
}

// Format implements fmt.Formatter.
func (h Hash) Format(s fmt.State, c rune) {
	fmt.Fprintf(s, "%"+string(c), h[:])
}

// Address represents the 20 byte address of an Ethereum account.
type Address [AddressLength]byte

// BytesToAddress returns Address with value b.
// If b is larger than len(h), b will be cropped from the left.
func BytesToAddress(b []byte) Address {
	var a Address
	a.SetBytes(b)
	return a
}

// BigToAddress returns Address with byte values of b.
// If b is larger than len(h), b will be cropped from the left.
func BigToAddress(b *big.Int) Address { return BytesToAddress(b.Bytes()) }

// HexToAddress returns Address with byte values of s.
// If s is larger than len(h), s will be cropped from the left.
func HexToAddress(s string) Address { return BytesToAddress(FromHex(s)) }

// IsHexAddress verifies whether a string can represent a valid hex-encoded
// Ethereum address or not.
func IsHexAddress(s string) bool {
	if has0xPrefix(s) {
		s = s[2:]
	}
	return len(s) == 2*AddressLength && isHex(s)
}

// Bytes gets the string representation of the underlying address.
func (a Address) Bytes() []byte { return a[:] }

// Big converts an address to a big integer.
func (a Address) Big() *big.Int { return new(big.Int).SetBytes(a[:]) }

// Hex returns an EIP55-compliant hex string representation of the address.
func (a Address) Hex() string {
	return string(a.checksumHex())
}

// String implements fmt.Stringer.
func (a Address) String() string {
	return a.Hex()
}

func (a *Address) checksumHex() []byte {
	buf := a.hex()

	// compute checksum
	hash := keccak256Checksum(buf[2:])
	for i := 2; i < len(buf); i++ {
		hashByte := hash[(i-2)/2]
		if i%2 == 0 {
			hashByte = hashByte >> 4
		} else {
			hashByte &= 0xf
		}
		if buf[i] > '9' && hashByte > 7 {
			buf[i] -= 32
		}
	}
	return buf
}

func (a Address) hex() []byte {
	var buf [len(a)*2 + 2]byte
	copy(buf[:2], "0x")
	hex.Encode(buf[2:], a[:])
	return buf[:]
}

// SetBytes sets the address to the value of b.
// If b is larger than len(a), b will be cropped from the left.
func (a *Address) SetBytes(b []byte) {
	if len(b) > len(a) {
		b = b[len(b)-AddressLength:]
	}
	copy(a[AddressLength-len(b):], b)
}

// MarshalText returns the hex representation of a.
func (a Address) MarshalText() ([]byte, error) {
	return hexEncode(a[:]), nil
}

// UnmarshalText parses a hash in hex syntax.
func (a *Address) UnmarshalText(input []byte) error {
	return hexDecode(a[:], input)
}

// UnmarshalJSON parses a hash in hex syntax.
func (a *Address) UnmarshalJSON(input []byte) error {
	return hexDecode(a[:], input)
}

// Scan implements Scanner for database/sql.
func (a *Address) Scan(src interface{}) error {
	srcB, ok := src.([]byte)
	if !ok {
		return fmt.Errorf("can't scan %T into Address", src)
	}
	if len(srcB) != AddressLength {
		return fmt.Errorf("can't scan []byte of len %d into Address, want %d", len(srcB), AddressLength)
	}
	copy(a[:], srcB)
	return nil
}

// Value implements valuer for database/sql.
func (a Address) Value() (driver.Value, error) {
	return a[:], nil
}

// Format implements fmt.Formatter.
func (a Address) Format(s fmt.State, c rune) {
	fmt.Fprintf(s, "%"+string(c), a[:])
}

// Hash converts an address to a hash by left-padding it with zeros.
func (a Address) Hash() Hash { return BytesToHash(a[:]) }

// Cmp compares two addresses.
func (a Address) Cmp(b Address) int {
	return bytes.Compare(a[:], b[:])
}

// Helper functions

func has0xPrefix(str string) bool {
	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}

func isHex(str string) bool {
	if len(str)%2 != 0 {
		return false
	}
	for _, c := range []byte(str) {
		if !isHexCharacter(c) {
			return false
		}
	}
	return true
}

func isHexCharacter(c byte) bool {
	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}

// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
	if has0xPrefix(s) {
		s = s[2:]
	}
	if len(s)%2 == 1 {
		s = "0" + s
	}
	h, _ := hex.DecodeString(s)
	return h
}

// 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
}

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

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

func hexEncode(b []byte) []byte {
	enc := make([]byte, len(b)*2+2)
	copy(enc, "0x")
	hex.Encode(enc[2:], b)
	return enc
}

func hexEncodeToString(b []byte) string {
	return string(hexEncode(b))
}

func hexDecode(b, input []byte) error {
	if !isQuoted(input) {
		_, err := hex.Decode(b, input)
		return err
	}
	return hexDecodeQuoted(b, input)
}

func hexDecodeQuoted(b, input []byte) error {
	if len(input) < 2 || input[0] != '"' || input[len(input)-1] != '"' {
		return fmt.Errorf("quoted value must start and end with quotes")
	}
	input = input[1 : len(input)-1]
	if has0xPrefix(string(input)) {
		input = input[2:]
	}
	if len(input) == 0 {
		return nil
	}
	_, err := hex.Decode(b, input)
	return err
}

func isQuoted(s []byte) bool {
	return len(s) >= 2 && s[0] == '"' && s[len(s)-1] == '"'
}

// keccak256Checksum calculates and returns the Keccak256 checksum of the input data.
// This is a simplified version for address checksum calculation.
func keccak256Checksum(data []byte) []byte {
	// We'll use a simple Keccak256 implementation here
	hasher := sha3.NewLegacyKeccak256()
	hasher.Write(data)
	return hasher.Sum(nil)
}