go-ethereum/accounts/abi/numbers.go
Jeffrey Wilcke 5127ec10cb accouns/abi: refactored ABI package
Refactored the abi package parsing and type handling. Relying mostly on
package reflect as opposed to most of our own type reflection. Our own
type reflection is still used however for cases such as Bytes and
FixedBytes (abi: bytes•).

This also inclused several fixes for slice handling of arbitrary and
fixed size for all supported types.

This also further removes implicit type casting such as assigning,
for example `[2]T{} = []T{1}` will fail, however `[2]T{} == []T{1, 2}`
(notice assigning *slice* to fixed size *array*). Assigning arrays to
slices will always succeed if they are of the same element type.

Incidentally also fixes #2379
2016-04-20 16:43:57 +02:00

125 lines
3.6 KiB
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 abi
import (
"math/big"
"reflect"
"github.com/ethereum/go-ethereum/common"
)
var (
big_t = reflect.TypeOf(big.Int{})
ubig_t = reflect.TypeOf(big.Int{})
byte_t = reflect.TypeOf(byte(0))
byte_ts = reflect.TypeOf([]byte(nil))
uint_t = reflect.TypeOf(uint(0))
uint8_t = reflect.TypeOf(uint8(0))
uint16_t = reflect.TypeOf(uint16(0))
uint32_t = reflect.TypeOf(uint32(0))
uint64_t = reflect.TypeOf(uint64(0))
int_t = reflect.TypeOf(int(0))
int8_t = reflect.TypeOf(int8(0))
int16_t = reflect.TypeOf(int16(0))
int32_t = reflect.TypeOf(int32(0))
int64_t = reflect.TypeOf(int64(0))
hash_t = reflect.TypeOf(common.Hash{})
address_t = reflect.TypeOf(common.Address{})
uint_ts = reflect.TypeOf([]uint(nil))
uint8_ts = reflect.TypeOf([]uint8(nil))
uint16_ts = reflect.TypeOf([]uint16(nil))
uint32_ts = reflect.TypeOf([]uint32(nil))
uint64_ts = reflect.TypeOf([]uint64(nil))
ubig_ts = reflect.TypeOf([]*big.Int(nil))
int_ts = reflect.TypeOf([]int(nil))
int8_ts = reflect.TypeOf([]int8(nil))
int16_ts = reflect.TypeOf([]int16(nil))
int32_ts = reflect.TypeOf([]int32(nil))
int64_ts = reflect.TypeOf([]int64(nil))
big_ts = reflect.TypeOf([]*big.Int(nil))
)
// U256 will ensure unsigned 256bit on big nums
func U256(n *big.Int) []byte {
return common.LeftPadBytes(common.U256(n).Bytes(), 32)
}
func S256(n *big.Int) []byte {
sint := common.S256(n)
ret := common.LeftPadBytes(sint.Bytes(), 32)
if sint.Cmp(common.Big0) < 0 {
for i, b := range ret {
if b == 0 {
ret[i] = 1
continue
}
break
}
}
return ret
}
// S256 will ensure signed 256bit on big nums
func U2U256(n uint64) []byte {
return U256(big.NewInt(int64(n)))
}
func S2S256(n int64) []byte {
return S256(big.NewInt(n))
}
// packNum packs the given number (using the reflect value) and will cast it to appropriate number representation
func packNum(value reflect.Value, to byte) []byte {
switch kind := value.Kind(); kind {
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if to == UintTy {
return U2U256(value.Uint())
} else {
return S2S256(int64(value.Uint()))
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if to == UintTy {
return U2U256(uint64(value.Int()))
} else {
return S2S256(value.Int())
}
case reflect.Ptr:
// This only takes care of packing and casting. No type checking is done here. It should be done prior to using this function.
if to == UintTy {
return U256(value.Interface().(*big.Int))
} else {
return S256(value.Interface().(*big.Int))
}
}
return nil
}
// checks whether the given reflect value is signed. This also works for slices with a number type
func isSigned(v reflect.Value) bool {
switch v.Type() {
case int_ts, int8_ts, int16_ts, int32_ts, int64_ts, int_t, int8_t, int16_t, int32_t, int64_t:
return true
}
return false
}