path: root/vm/stack.go

package vm

import (
    "fmt"
    "math"
    "math/big"
)

type OpType int

const (
    tNorm = iota
    tData
    tExtro
    tCrypto
)

type TxCallback func(opType OpType) bool

// Simple push/pop stack mechanism
type Stack struct {
    data []*big.Int
}

func NewStack() *Stack {
    return &Stack{}
}

func (st *Stack) Data() []*big.Int {
    return st.data
}

func (st *Stack) Len() int {
    return len(st.data)
}

func (st *Stack) Pop() *big.Int {
    str := st.data[len(st.data)-1]

    copy(st.data[:len(st.data)-1], st.data[:len(st.data)-1])
    st.data = st.data[:len(st.data)-1]

    return str
}

func (st *Stack) Popn() (*big.Int, *big.Int) {
    ints := st.data[len(st.data)-2:]

    copy(st.data[:len(st.data)-2], st.data[:len(st.data)-2])
    st.data = st.data[:len(st.data)-2]

    return ints[0], ints[1]
}

func (st *Stack) Peek() *big.Int {
    str := st.data[len(st.data)-1]

    return str
}

func (st *Stack) Peekn() (*big.Int, *big.Int) {
    ints := st.data[len(st.data)-2:]

    return ints[0], ints[1]
}

func (st *Stack) Swapn(n int) (*big.Int, *big.Int) {
    st.data[len(st.data)-n], st.data[len(st.data)-1] = st.data[len(st.data)-1], st.data[len(st.data)-n]

    return st.data[len(st.data)-n], st.data[len(st.data)-1]
}

func (st *Stack) Dupn(n int) *big.Int {
    st.Push(st.data[len(st.data)-n])

    return st.Peek()
}

func (st *Stack) Push(d *big.Int) {
    st.data = append(st.data, new(big.Int).Set(d))
}

func (st *Stack) Get(amount *big.Int) []*big.Int {
    // offset + size <= len(data)
    length := big.NewInt(int64(len(st.data)))
    if amount.Cmp(length) <= 0 {
        start := new(big.Int).Sub(length, amount)
        return st.data[start.Int64():length.Int64()]
    }

    return nil
}

func (st *Stack) Print() {
    fmt.Println("### stack ###")
    if len(st.data) > 0 {
        for i, val := range st.data {
            fmt.Printf("%-3d  %v\n", i, val)
        }
    } else {
        fmt.Println("-- empty --")
    }
    fmt.Println("#############")
}

type Memory struct {
    store []byte
}

func NewMemory() *Memory {
    return &Memory{nil}
}

func (m *Memory) Set(offset, size uint64, value []byte) {
    if len(value) > 0 {
        totSize := offset + size
        lenSize := uint64(len(m.store) - 1)
        if totSize > lenSize {
            // Calculate the diff between the sizes
            diff := totSize - lenSize
            if diff > 0 {
                // Create a new empty slice and append it
                newSlice := make([]byte, diff-1)
                // Resize slice
                m.store = append(m.store, newSlice...)
            }
        }
        copy(m.store[offset:offset+size], value)
    }
}

func (m *Memory) Resize(size uint64) {
    if uint64(m.Len()) < size {
        m.store = append(m.store, make([]byte, size-uint64(m.Len()))...)
    }
}

func (m *Memory) Get(offset, size int64) []byte {
    if len(m.store) > int(offset) {
        end := int(math.Min(float64(len(m.store)), float64(offset+size)))

        return m.store[offset:end]
    }

    return nil
}

func (self *Memory) Geti(offset, size int64) (cpy []byte) {
    if len(self.store) > int(offset) {
        cpy = make([]byte, size)
        copy(cpy, self.store[offset:offset+size])

        return
    }

    return
}

func (m *Memory) Len() int {
    return len(m.store)
}

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("####################")
}