236 lines
7.6 KiB
Go
236 lines
7.6 KiB
Go
// Copyright 2015 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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"encoding/binary"
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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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)
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// toGoSliceType parses the input and casts it to the proper slice defined by the ABI
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// argument in T.
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func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
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index := i * 32
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// The slice must, at very least be large enough for the index+32 which is exactly the size required
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// for the [offset in output, size of offset].
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if index+32 > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go slice: insufficient size output %d require %d", len(output), index+32)
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}
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elem := t.Type.Elem
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// first we need to create a slice of the type
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var refSlice reflect.Value
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switch elem.T {
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case IntTy, UintTy, BoolTy:
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// create a new reference slice matching the element type
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switch t.Type.Kind {
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case reflect.Bool:
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refSlice = reflect.ValueOf([]bool(nil))
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case reflect.Uint8:
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refSlice = reflect.ValueOf([]uint8(nil))
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case reflect.Uint16:
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refSlice = reflect.ValueOf([]uint16(nil))
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case reflect.Uint32:
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refSlice = reflect.ValueOf([]uint32(nil))
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case reflect.Uint64:
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refSlice = reflect.ValueOf([]uint64(nil))
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case reflect.Int8:
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refSlice = reflect.ValueOf([]int8(nil))
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case reflect.Int16:
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refSlice = reflect.ValueOf([]int16(nil))
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case reflect.Int32:
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refSlice = reflect.ValueOf([]int32(nil))
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case reflect.Int64:
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refSlice = reflect.ValueOf([]int64(nil))
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default:
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refSlice = reflect.ValueOf([]*big.Int(nil))
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}
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case AddressTy: // address must be of slice Address
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refSlice = reflect.ValueOf([]common.Address(nil))
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case HashTy: // hash must be of slice hash
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refSlice = reflect.ValueOf([]common.Hash(nil))
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case FixedBytesTy:
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refSlice = reflect.ValueOf([][]byte(nil))
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default: // no other types are supported
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return nil, fmt.Errorf("abi: unsupported slice type %v", elem.T)
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}
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var slice []byte
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var size int
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var offset int
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if t.Type.IsSlice {
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// get the offset which determines the start of this array ...
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offset = int(binary.BigEndian.Uint64(output[index+24 : index+32]))
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if offset+32 > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go slice: offset %d would go over slice boundary (len=%d)", len(output), offset+32)
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}
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slice = output[offset:]
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// ... starting with the size of the array in elements ...
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size = int(binary.BigEndian.Uint64(slice[24:32]))
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slice = slice[32:]
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// ... and make sure that we've at the very least the amount of bytes
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// available in the buffer.
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if size*32 > len(slice) {
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return nil, fmt.Errorf("abi: cannot marshal in to go slice: insufficient size output %d require %d", len(output), offset+32+size*32)
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}
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// reslice to match the required size
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slice = slice[:size*32]
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} else if t.Type.IsArray {
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//get the number of elements in the array
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size = t.Type.SliceSize
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//check to make sure array size matches up
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if index+32*size > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), index+32*size)
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}
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//slice is there for a fixed amount of times
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slice = output[index : index+size*32]
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}
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for i := 0; i < size; i++ {
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var (
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inter interface{} // interface type
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returnOutput = slice[i*32 : i*32+32] // the return output
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err error
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)
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// set inter to the correct type (cast)
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switch elem.T {
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case IntTy, UintTy:
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inter = readInteger(t.Type.Kind, returnOutput)
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case BoolTy:
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inter, err = readBool(returnOutput)
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if err != nil {
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return nil, err
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}
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case AddressTy:
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inter = common.BytesToAddress(returnOutput)
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case HashTy:
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inter = common.BytesToHash(returnOutput)
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case FixedBytesTy:
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inter = returnOutput
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}
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// append the item to our reflect slice
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refSlice = reflect.Append(refSlice, reflect.ValueOf(inter))
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}
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// return the interface
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return refSlice.Interface(), nil
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}
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func readInteger(kind reflect.Kind, b []byte) interface{} {
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switch kind {
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case reflect.Uint8:
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return uint8(b[len(b)-1])
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case reflect.Uint16:
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return binary.BigEndian.Uint16(b[len(b)-2:])
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case reflect.Uint32:
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return binary.BigEndian.Uint32(b[len(b)-4:])
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case reflect.Uint64:
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return binary.BigEndian.Uint64(b[len(b)-8:])
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case reflect.Int8:
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return int8(b[len(b)-1])
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case reflect.Int16:
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return int16(binary.BigEndian.Uint16(b[len(b)-2:]))
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case reflect.Int32:
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return int32(binary.BigEndian.Uint32(b[len(b)-4:]))
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case reflect.Int64:
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return int64(binary.BigEndian.Uint64(b[len(b)-8:]))
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default:
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return new(big.Int).SetBytes(b)
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}
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}
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func readBool(word []byte) (bool, error) {
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if len(word) != 32 {
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return false, fmt.Errorf("abi: fatal error: incorrect word length")
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}
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for i, b := range word {
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if b != 0 && i != 31 {
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return false, errBadBool
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}
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}
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switch word[31] {
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case 0:
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return false, nil
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case 1:
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return true, nil
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default:
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return false, errBadBool
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}
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}
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// toGoType parses the input and casts it to the proper type defined by the ABI
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// argument in T.
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func toGoType(i int, t Argument, output []byte) (interface{}, error) {
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// we need to treat slices differently
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if (t.Type.IsSlice || t.Type.IsArray) && t.Type.T != BytesTy && t.Type.T != StringTy && t.Type.T != FixedBytesTy && t.Type.T != FunctionTy {
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return toGoSlice(i, t, output)
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}
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index := i * 32
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if index+32 > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), index+32)
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}
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// Parse the given index output and check whether we need to read
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// a different offset and length based on the type (i.e. string, bytes)
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var returnOutput []byte
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switch t.Type.T {
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case StringTy, BytesTy: // variable arrays are written at the end of the return bytes
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// parse offset from which we should start reading
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offset := int(binary.BigEndian.Uint64(output[index+24 : index+32]))
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if offset+32 > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32)
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}
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// parse the size up until we should be reading
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size := int(binary.BigEndian.Uint64(output[offset+24 : offset+32]))
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if offset+32+size > len(output) {
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return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+size)
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}
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// get the bytes for this return value
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returnOutput = output[offset+32 : offset+32+size]
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default:
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returnOutput = output[index : index+32]
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}
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// convert the bytes to whatever is specified by the ABI.
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switch t.Type.T {
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case IntTy, UintTy:
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return readInteger(t.Type.Kind, returnOutput), nil
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case BoolTy:
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return readBool(returnOutput)
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case AddressTy:
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return common.BytesToAddress(returnOutput), nil
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case HashTy:
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return common.BytesToHash(returnOutput), nil
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case BytesTy, FixedBytesTy, FunctionTy:
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return returnOutput, nil
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case StringTy:
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return string(returnOutput), nil
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}
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return nil, fmt.Errorf("abi: unknown type %v", t.Type.T)
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}
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