forked from cerc-io/plugeth
8b57c49490
Reworked the EVM gas instructions to use 64bit integers rather than arbitrary size big ints. All gas operations, be it additions, multiplications or divisions, are checked and guarded against 64 bit integer overflows. In additon, most of the protocol paramaters in the params package have been converted to uint64 and are now constants rather than variables. * common/math: added overflow check ops * core: vmenv, env renamed to evm * eth, internal/ethapi, les: unmetered eth_call and cancel methods * core/vm: implemented big.Int pool for evm instructions * core/vm: unexported intPool methods & verification methods * core/vm: added memoryGasCost overflow check and test
105 lines
2.6 KiB
Go
105 lines
2.6 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 vm
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import "fmt"
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// Memory implements a simple memory model for the ethereum virtual machine.
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type Memory struct {
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store []byte
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lastGasCost uint64
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}
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func NewMemory() *Memory {
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return &Memory{}
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}
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// Set sets offset + size to value
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func (m *Memory) Set(offset, size uint64, value []byte) {
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// length of store may never be less than offset + size.
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// The store should be resized PRIOR to setting the memory
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if size > uint64(len(m.store)) {
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panic("INVALID memory: store empty")
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}
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// It's possible the offset is greater than 0 and size equals 0. This is because
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// the calcMemSize (common.go) could potentially return 0 when size is zero (NO-OP)
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if size > 0 {
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copy(m.store[offset:offset+size], value)
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}
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}
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// Resize resizes the memory to size
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func (m *Memory) Resize(size uint64) {
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if uint64(m.Len()) < size {
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m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
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}
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}
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// Get returns offset + size as a new slice
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func (self *Memory) Get(offset, size int64) (cpy []byte) {
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if size == 0 {
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return nil
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}
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if len(self.store) > int(offset) {
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cpy = make([]byte, size)
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copy(cpy, self.store[offset:offset+size])
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return
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}
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return
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}
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// GetPtr returns the offset + size
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func (self *Memory) GetPtr(offset, size int64) []byte {
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if size == 0 {
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return nil
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}
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if len(self.store) > int(offset) {
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return self.store[offset : offset+size]
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}
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return nil
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}
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// Len returns the length of the backing slice
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func (m *Memory) Len() int {
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return len(m.store)
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}
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// Data returns the backing slice
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func (m *Memory) Data() []byte {
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return m.store
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}
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func (m *Memory) Print() {
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fmt.Printf("### mem %d bytes ###\n", len(m.store))
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if len(m.store) > 0 {
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addr := 0
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for i := 0; i+32 <= len(m.store); i += 32 {
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fmt.Printf("%03d: % x\n", addr, m.store[i:i+32])
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addr++
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}
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} else {
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fmt.Println("-- empty --")
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}
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fmt.Println("####################")
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}
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