types.go

// Copyright 2015 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 ethadaptor

import (
	"database/sql/driver"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"math/big"
	"math/rand"
	"reflect"
	"strings"
	//"github.com/ethereum/go-ethereum/common/hexutil"
	//"github.com/ethereum/go-ethereum/crypto/sha3"
)

// Lengths of hashes and addresses in bytes.
const (
	// HashLength is the expected length of the hash
	HashLength = 32
	// AddressLength is the expected length of the address
	AddressLength = 20
)

//var (
//	hashT    = reflect.TypeOf(Hash{})
//	addressT = reflect.TypeOf(Address{})
//)

// 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()) }

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

// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
	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)
}

// 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 hexutil.Encode(h[:]) }

// TerminalString implements log.TerminalStringer, formatting a string for console
// output during logging.
func (h Hash) TerminalString() string {
	return fmt.Sprintf("%x…%x", h[:3], h[29:])
}

//// 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()
//}

// Format implements fmt.Formatter, forcing the byte slice to be formatted as is,
// without going through the stringer interface used for logging.
func (h Hash) Format(s fmt.State, c rune) {
	fmt.Fprintf(s, "%"+string(c), h[:])
}

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

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

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

// 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) reflect.Value {
	m := rand.Intn(len(h))
	for i := len(h) - 1; i > m; i-- {
		h[i] = byte(rand.Uint32())
	}
	return reflect.ValueOf(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
}

// UnprefixedHash allows marshaling a Hash without 0x prefix.
type UnprefixedHash Hash

//// UnmarshalText decodes the hash from hex. The 0x prefix is optional.
//func (h *UnprefixedHash) UnmarshalText(input []byte) error {
//	return hexutil.UnmarshalFixedUnprefixedText("UnprefixedHash", input, h[:])
//}

// MarshalText encodes the hash as hex.
func (h UnprefixedHash) MarshalText() ([]byte, error) {
	return []byte(hex.EncodeToString(h[:])), nil
}

/////////// Address

// 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)) }

// 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')
}

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

// 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
}

// 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[:]) }

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

//// Hex returns an EIP55-compliant hex string representation of the address.
//func (a Address) Hex() string {
//	unchecksummed := hex.EncodeToString(a[:])
//	sha := sha3.NewKeccak256()
//	sha.Write([]byte(unchecksummed))
//	hash := sha.Sum(nil)

//	result := []byte(unchecksummed)
//	for i := 0; i < len(result); i++ {
//		hashByte := hash[i/2]
//		if i%2 == 0 {
//			hashByte = hashByte >> 4
//		} else {
//			hashByte &= 0xf
//		}
//		if result[i] > '9' && hashByte > 7 {
//			result[i] -= 32
//		}
//	}
//	return "0x" + string(result)
//}

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

// Format implements fmt.Formatter, forcing the byte slice to be formatted as is,
// without going through the stringer interface used for logging.
func (a Address) Format(s fmt.State, c rune) {
	fmt.Fprintf(s, "%"+string(c), a[:])
}

// SetBytes sets the address to the value of b.
// If b is larger than len(a) it will panic.
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 hexutil.Bytes(a[:]).MarshalText()
//}

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

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

// 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
}

// UnprefixedAddress allows marshaling an Address without 0x prefix.
type UnprefixedAddress Address

//// UnmarshalText decodes the address from hex. The 0x prefix is optional.
//func (a *UnprefixedAddress) UnmarshalText(input []byte) error {
//	return hexutil.UnmarshalFixedUnprefixedText("UnprefixedAddress", input, a[:])
//}

// MarshalText encodes the address as hex.
func (a UnprefixedAddress) MarshalText() ([]byte, error) {
	return []byte(hex.EncodeToString(a[:])), nil
}

// MixedcaseAddress retains the original string, which may or may not be
// correctly checksummed
type MixedcaseAddress struct {
	addr     Address
	original string
}

//// NewMixedcaseAddress constructor (mainly for testing)
//func NewMixedcaseAddress(addr Address) MixedcaseAddress {
//	return MixedcaseAddress{addr: addr, original: addr.Hex()}
//}

// NewMixedcaseAddressFromString is mainly meant for unit-testing
func NewMixedcaseAddressFromString(hexaddr string) (*MixedcaseAddress, error) {
	if !IsHexAddress(hexaddr) {
		return nil, fmt.Errorf("invalid address")
	}
	a := FromHex(hexaddr)
	return &MixedcaseAddress{addr: BytesToAddress(a), original: hexaddr}, nil
}

//// UnmarshalJSON parses MixedcaseAddress
//func (ma *MixedcaseAddress) UnmarshalJSON(input []byte) error {
//	if err := hexutil.UnmarshalFixedJSON(addressT, input, ma.addr[:]); err != nil {
//		return err
//	}
//	return json.Unmarshal(input, &ma.original)
//}

// MarshalJSON marshals the original value
func (ma *MixedcaseAddress) MarshalJSON() ([]byte, error) {
	if strings.HasPrefix(ma.original, "0x") || strings.HasPrefix(ma.original, "0X") {
		return json.Marshal(fmt.Sprintf("0x%s", ma.original[2:]))
	}
	return json.Marshal(fmt.Sprintf("0x%s", ma.original))
}

// Address returns the address
func (ma *MixedcaseAddress) Address() Address {
	return ma.addr
}

//// String implements fmt.Stringer
//func (ma *MixedcaseAddress) String() string {
//	if ma.ValidChecksum() {
//		return fmt.Sprintf("%s [chksum ok]", ma.original)
//	}
//	return fmt.Sprintf("%s [chksum INVALID]", ma.original)
//}

//// ValidChecksum returns true if the address has valid checksum
//func (ma *MixedcaseAddress) ValidChecksum() bool {
//	return ma.original == ma.addr.Hex()
//}

// Original returns the mixed-case input string
func (ma *MixedcaseAddress) Original() string {
	return ma.original
}