mirror of
https://github.com/nspcc-dev/neo-go.git
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102 lines
2.4 KiB
Go
102 lines
2.4 KiB
Go
package vm
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import (
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"math/big"
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"github.com/CityOfZion/neo-go/pkg/vm/stack"
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)
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// Stack Manipulation Opcodes
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// PushNBytes will Read N Bytes from the script and push it onto the stack
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func PushNBytes(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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val, err := ctx.ReadBytes(int(op))
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if err != nil {
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return FAULT, err
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}
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ba := stack.NewByteArray(val)
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ctx.Estack.Push(ba)
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return NONE, nil
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}
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// XSWAP pops an integer n off of the stack and
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// swaps the n-item from the stack starting from
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// the top of the stack with the top stack item.
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func XSWAP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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n, err := ctx.Estack.PopInt()
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if err != nil {
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return FAULT, err
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}
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nItem, err := ctx.Estack.Peek(uint16(n.Value().Int64()))
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if err != nil {
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return FAULT, err
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}
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item, err := ctx.Estack.Peek(0)
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if err != nil {
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return FAULT, err
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}
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if err := ctx.Estack.Set(uint16(n.Value().Int64()), item); err != nil {
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return FAULT, err
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}
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if err := ctx.Estack.Set(0, nItem); err != nil {
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return FAULT, err
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}
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return NONE, nil
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}
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// XTUCK pops an integer n off of the stack and
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// inserts the top stack item to the position len(stack)-n in the evaluation stack.
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func XTUCK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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n, err := ctx.Estack.PopInt()
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if err != nil || n.Value().Int64() < 0 {
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return FAULT, err
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}
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item, err := ctx.Estack.Peek(0)
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if err != nil {
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return FAULT, err
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}
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ras, err := ctx.Estack.Insert(uint16(n.Value().Int64()), item)
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if err != nil {
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return FAULT, err
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}
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ctx.Estack = *ras
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return NONE, nil
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}
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// DEPTH puts the number of stack items onto the stack.
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func DEPTH(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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l := ctx.Estack.Len()
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length, err := stack.NewInt(big.NewInt(int64(l)))
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if err != nil {
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return FAULT, err
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}
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ctx.Estack.Push(length)
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return NONE, nil
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}
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// DROP removes the the top stack item.
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// Returns error if the operation Pop cannot
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// be performed.
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func DROP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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_, err := ctx.Estack.Pop()
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if err != nil {
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return FAULT, err
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}
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return NONE, nil
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}
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