plugeth/core/vm/memory.go
Jeffrey Wilcke 361082ec4b cmd/evm, core/vm, test: refactored VM and core
* Moved `vm.Transfer` to `core` package and changed execution to call
`env.Transfer` instead of `core.Transfer` directly.
* core/vm: byte code VM moved to jump table instead of switch
* Moved `vm.Transfer` to `core` package and changed execution to call
  `env.Transfer` instead of `core.Transfer` directly.
* Byte code VM now shares the same code as the JITVM
* Renamed Context to Contract
* Changed initialiser of state transition & unexported methods
* Removed the Execution object and refactor `Call`, `CallCode` &
  `Create` in to their own functions instead of being methods.
* Removed the hard dep on the state for the VM. The VM now
  depends on a Database interface returned by the environment. In the
  process the core now depends less on the statedb by usage of the env
* Moved `Log` from package `core/state` to package `core/vm`.
2015-10-04 01:13:54 +02:00

104 lines
2.6 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 vm
import "fmt"
// Memory implements ethereum RAM backed by a simple byte slice
type Memory struct {
store []byte
}
func NewMemory() *Memory {
return &Memory{nil}
}
// Set sets offset + size to value
func (m *Memory) Set(offset, size uint64, value []byte) {
// length of store may never be less than offset + size.
// The store should be resized PRIOR to setting the memory
if size > uint64(len(m.store)) {
panic("INVALID memory: store empty")
}
// It's possible the offset is greater than 0 and size equals 0. This is because
// the calcMemSize (common.go) could potentially return 0 when size is zero (NO-OP)
if size > 0 {
copy(m.store[offset:offset+size], value)
}
}
// Resize resizes the memory to size
func (m *Memory) Resize(size uint64) {
if uint64(m.Len()) < size {
m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
}
}
// Get returns offset + size as a new slice
func (self *Memory) Get(offset, size int64) (cpy []byte) {
if size == 0 {
return nil
}
if len(self.store) > int(offset) {
cpy = make([]byte, size)
copy(cpy, self.store[offset:offset+size])
return
}
return
}
// GetPtr returns the offset + size
func (self *Memory) GetPtr(offset, size int64) []byte {
if size == 0 {
return nil
}
if len(self.store) > int(offset) {
return self.store[offset : offset+size]
}
return nil
}
// Len returns the length of the backing slice
func (m *Memory) Len() int {
return len(m.store)
}
// Data returns the backing slice
func (m *Memory) Data() []byte {
return m.store
}
func (m *Memory) Print() {
fmt.Printf("### mem %d bytes ###\n", len(m.store))
if len(m.store) > 0 {
addr := 0
for i := 0; i+32 <= len(m.store); i += 32 {
fmt.Printf("%03d: % x\n", addr, m.store[i:i+32])
addr++
}
} else {
fmt.Println("-- empty --")
}
fmt.Println("####################")
}