package vm import ( "fmt" . "github.com/tendermint/tendermint/common" ) // Not goroutine safe type Stack struct { data []Word256 ptr int gas *int64 err *error } func NewStack(capacity int, gas *int64, err *error) *Stack { return &Stack{ data: make([]Word256, capacity), ptr: 0, gas: gas, err: err, } } func (st *Stack) useGas(gasToUse int64) { if *st.gas > gasToUse { *st.gas -= gasToUse } else { st.setErr(ErrInsufficientGas) } } func (st *Stack) setErr(err error) { if *st.err == nil { *st.err = err } } func (st *Stack) Push(d Word256) { st.useGas(GasStackOp) if st.ptr == cap(st.data) { st.setErr(ErrDataStackOverflow) return } st.data[st.ptr] = d st.ptr++ } // currently only called after Sha3 func (st *Stack) PushBytes(bz []byte) { if len(bz) != 32 { panic("Invalid bytes size: expected 32") } st.Push(LeftPadWord256(bz)) } func (st *Stack) Push64(i int64) { st.Push(Int64ToWord256(i)) } func (st *Stack) Pop() Word256 { st.useGas(GasStackOp) if st.ptr == 0 { st.setErr(ErrDataStackUnderflow) return Zero256 } st.ptr-- return st.data[st.ptr] } func (st *Stack) PopBytes() []byte { return st.Pop().Bytes() } func (st *Stack) Pop64() int64 { d := st.Pop() return Int64FromWord256(d) } func (st *Stack) Len() int { return st.ptr } func (st *Stack) Swap(n int) { st.useGas(GasStackOp) if st.ptr < n { st.setErr(ErrDataStackUnderflow) return } st.data[st.ptr-n], st.data[st.ptr-1] = st.data[st.ptr-1], st.data[st.ptr-n] return } func (st *Stack) Dup(n int) { st.useGas(GasStackOp) if st.ptr < n { st.setErr(ErrDataStackUnderflow) return } st.Push(st.data[st.ptr-n]) return } // Not an opcode, costs no gas. func (st *Stack) Peek() Word256 { return st.data[st.ptr-1] } func (st *Stack) Print(n int) { fmt.Println("### stack ###") if st.ptr > 0 { nn := MinInt(n, st.ptr) for j, i := 0, st.ptr-1; i > st.ptr-1-nn; i-- { fmt.Printf("%-3d %X\n", j, st.data[i]) j += 1 } } else { fmt.Println("-- empty --") } fmt.Println("#############") }