86 lines
3.0 KiB
Go
86 lines
3.0 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package abi
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import (
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"errors"
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"fmt"
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"math/big"
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"reflect"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/math"
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)
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// packBytesSlice packs the given bytes as [L, V] as the canonical representation
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// bytes slice.
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func packBytesSlice(bytes []byte, l int) []byte {
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len := packNum(reflect.ValueOf(l))
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return append(len, common.RightPadBytes(bytes, (l+31)/32*32)...)
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}
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// packElement packs the given reflect value according to the abi specification in
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// t.
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func packElement(t Type, reflectValue reflect.Value) ([]byte, error) {
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switch t.T {
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case IntTy, UintTy:
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return packNum(reflectValue), nil
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case StringTy:
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return packBytesSlice([]byte(reflectValue.String()), reflectValue.Len()), nil
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case AddressTy:
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if reflectValue.Kind() == reflect.Array {
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reflectValue = mustArrayToByteSlice(reflectValue)
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}
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return common.LeftPadBytes(reflectValue.Bytes(), 32), nil
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case BoolTy:
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if reflectValue.Bool() {
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return math.PaddedBigBytes(common.Big1, 32), nil
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}
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return math.PaddedBigBytes(common.Big0, 32), nil
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case BytesTy:
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if reflectValue.Kind() == reflect.Array {
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reflectValue = mustArrayToByteSlice(reflectValue)
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}
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if reflectValue.Type() != reflect.TypeOf([]byte{}) {
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return []byte{}, errors.New("bytes type is neither slice nor array")
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}
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return packBytesSlice(reflectValue.Bytes(), reflectValue.Len()), nil
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case FixedBytesTy, FunctionTy:
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if reflectValue.Kind() == reflect.Array {
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reflectValue = mustArrayToByteSlice(reflectValue)
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}
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return common.RightPadBytes(reflectValue.Bytes(), 32), nil
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default:
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return []byte{}, fmt.Errorf("could not pack element, unknown type: %v", t.T)
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}
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}
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// packNum packs the given number (using the reflect value) and will cast it to appropriate number representation.
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func packNum(value reflect.Value) []byte {
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switch kind := value.Kind(); kind {
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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return math.U256Bytes(new(big.Int).SetUint64(value.Uint()))
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return math.U256Bytes(big.NewInt(value.Int()))
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case reflect.Ptr:
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return math.U256Bytes(new(big.Int).Set(value.Interface().(*big.Int)))
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default:
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panic("abi: fatal error")
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}
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}
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