neo-go/pkg/vm/stack/bytearray.go
decentralisedkev c1b6738bdb
VM: Add basic vm (#166)
* VM:Add abstract stack item

* VM: Add stackItems; Array, Boolean, Int and ByteArray

* VM: Add tests for stack item

* VM: first pass at Random Access Stack object

* VM: Add Sub, Mul, Mod LSH, RSH

* VM: moved test helper functions into separate file

* VM: removed helper functions from stack_test.go

* Add conversions for bytearray and Int stack items

* Add instructions file for vm

* - Add guide to stack readme
- Add testReadInt64

* Add Builder

* Refactor Int, Boolean, ByteArray conversion

* Add Context stack Item

* Add Invocation stack - convenience RAS

* rename testhelper to test_helper

* Move opcode file

* - Add `Add` OpCode
- Add Opcode Function map

* - Add test for math `Add` opcode
- basic opcode execution

* Add popTwoIntegers convenience func

* Add `SUB` Opcode

* Export Context Read methods
- Return errors where failable

* - Add `Op` to handleOP func signature
- Add PushNBytes OPcode

* remove error on NewBoolean
- Expose underlying with Getter on Boolean StackItem
- Add Equals method for ByteArray

* Make Next() method on Context failable, refactor peekContext and Peek

* Add ExecuteOp, Step and Run methods on the VM

* Add Equal Opcode

* Add THROWIFNOT Opcode

* Add RET Opcode

* Refactor PushNBytes Opcode

* refactor Add, Sub to return VMSTATE
add popTwoByteArrays helper function

* Add basic tests for vm

* clarify vm states

* Add astack

* [VM]

Pass ResultStack to the opcode handlers

* [VM]

refactor handlers to have rstack as argument

* [Stack]

- Change RemoveCurrentContext for PopCurrentContext
- Add CopTo method to stack

* [VM]

Add Result stack Len check in simple run test

* [VM] fix typo

* [Peer/Stall]

Change seconds to milliseconds in test
2019-03-18 21:40:21 +00:00

71 lines
1.5 KiB
Go

package stack
import (
"bytes"
"errors"
"math/big"
"strconv"
)
// ByteArray represents a slice of bytes on the stack
type ByteArray struct {
*abstractItem
val []byte
}
//NewByteArray returns a ByteArray stack item
// given a byte slice
func NewByteArray(val []byte) *ByteArray {
return &ByteArray{
&abstractItem{},
val,
}
}
//ByteArray overrides the default abstractItem Bytes array method
func (ba *ByteArray) ByteArray() (*ByteArray, error) {
return ba, nil
}
//Equals returns true, if two bytearrays are equal
func (ba *ByteArray) Equals(other *ByteArray) *Boolean {
// If either are nil, return false
if ba == nil || other == nil {
return NewBoolean(false)
}
return NewBoolean(bytes.Equal(ba.val, other.val))
}
//Integer overrides the default Integer method to convert an
// ByteArray Into an integer
func (ba *ByteArray) Integer() (*Int, error) {
dest := reverse(ba.val)
integerVal := new(big.Int).SetBytes(dest)
return NewInt(integerVal)
}
// Boolean will convert a byte array into a boolean stack item
func (ba *ByteArray) Boolean() (*Boolean, error) {
boolean, err := strconv.ParseBool(string(ba.val))
if err != nil {
return nil, errors.New("cannot convert byte array to a boolean")
}
return NewBoolean(boolean), nil
}
// XXX: move this into a pkg/util/slice folder
// Go mod not working
func reverse(b []byte) []byte {
if len(b) < 2 {
return b
}
dest := make([]byte, len(b))
for i, j := 0, len(b)-1; i < j+1; i, j = i+1, j-1 {
dest[i], dest[j] = b[j], b[i]
}
return dest
}