internal_address.go

package common

import (
	"bytes"
	"database/sql/driver"
	"encoding/hex"
	"fmt"
	"reflect"

	"github.com/dominant-strategies/go-quai/common/hexutil"
	"golang.org/x/crypto/sha3"
)

type InternalAddress [AddressLength]byte

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

// Bytes20 gets the bytes20 representation of the underlying address.
func (a InternalAddress) Bytes20() (addr AddressBytes) { return AddressBytes(a) }

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

// Hex returns a hex string representation of the address.
func (a InternalAddress) Hex() string {
	return string(a.checksumHex())
}

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

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

	// compute checksum
	sha := sha3.NewLegacyKeccak256()
	sha.Write(buf[2:])
	hash := sha.Sum(nil)
	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 InternalAddress) hex() []byte {
	var buf [len(a)*2 + 2]byte
	copy(buf[:2], "0x")
	hex.Encode(buf[2:], a[:])
	return buf[:]
}

// Format implements fmt.Formatter.
// Address supports the %v, %s, %v, %x, %X and %d format verbs.
func (a InternalAddress) Format(s fmt.State, c rune) {
	switch c {
	case 'v', 's':
		s.Write(a.checksumHex())
	case 'q':
		q := []byte{'"'}
		s.Write(q)
		s.Write(a.checksumHex())
		s.Write(q)
	case 'x', 'X':
		// %x disables the checksum.
		hex := a.hex()
		if !s.Flag('#') {
			hex = hex[2:]
		}
		if c == 'X' {
			hex = bytes.ToUpper(hex)
		}
		s.Write(hex)
	case 'd':
		fmt.Fprint(s, ([len(a)]byte)(a))
	default:
		fmt.Fprintf(s, "%%!%c(address=%x)", c, a)
	}
}

// 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 *InternalAddress) setBytes(b []byte) { // May want to check scope here
	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 InternalAddress) MarshalText() ([]byte, error) {
	return hexutil.Bytes(a[:]).MarshalText()
}

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

// UnmarshalJSON parses a hash in hex syntax.
func (a *InternalAddress) UnmarshalJSON(input []byte) error {
	return hexutil.UnmarshalFixedJSON(reflect.TypeOf(InternalAddress{}), input, a[:])
}

// Scan implements Scanner for database/sql.
func (a *InternalAddress) 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 InternalAddress) Value() (driver.Value, error) {
	return a[:], nil
}

func (a InternalAddress) Location() *Location {
	// Extract nibbles
	lowerNib := a[0] & 0x0F        // Lower 4 bits
	upperNib := (a[0] & 0xF0) >> 4 // Upper 4 bits, shifted right
	return &Location{upperNib, lowerNib}
}

func (a InternalAddress) IsInQuaiLedgerScope() bool {
	// The first bit of the second byte is not set if the address is in the Quai ledger
	return a.Bytes()[1] <= 127
}

func (a InternalAddress) IsInQiLedgerScope() bool {
	// The first bit of the second byte is set if the address is in the Qi ledger
	return a.Bytes()[1] > 127
}