mirror of
https://github.com/nspcc-dev/neo-go.git
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93 lines
2.2 KiB
Go
93 lines
2.2 KiB
Go
package vm
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import (
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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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// ROLL pops an integer n off of the stack and
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// moves the n-item starting from
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// the top of the stack onto the top stack item.
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// Returns an error if the top stack item is not an
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// integer or n-item does not exist.
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func ROLL(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.Remove(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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ctx.Estack.Push(nItem)
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return NONE, nil
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}
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// ROT moves the third top stack item
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// onto the top stack item.
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// Returns an error if the third top stack item
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// does not exist.
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func ROT(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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item, err := ctx.Estack.Remove(2)
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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(item)
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return NONE, nil
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}
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// SWAP swaps the second top stack item with
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// the top stack item.
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// Returns an error if the second top stack item
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// does not exist.
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func SWAP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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item, err := ctx.Estack.Remove(1)
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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(item)
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return NONE, nil
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}
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// TUCK copies the top stack item and
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// inserts it before the second top stack item.
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// Returns an error if the stack is empty or
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// len(stack) is less or equal 2.
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func TUCK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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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(2, 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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