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122 lines
2.7 KiB
Go
122 lines
2.7 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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// Add adds two stack Items together.
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// Returns an error if either items cannot be casted to an integer
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// or if integers cannot be added together
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func Add(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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operandA, operandB, err := popTwoIntegers(ctx)
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if err != nil {
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return FAULT, err
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}
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res, err := operandA.Add(operandB)
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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(res)
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return NONE, nil
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}
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// Sub subtracts two stack Items.
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// Returns an error if either items cannot be casted to an integer
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// or if integers cannot be subtracted together
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func Sub(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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operandA, operandB, err := popTwoIntegers(ctx)
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if err != nil {
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return FAULT, err
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}
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res, err := operandB.Sub(operandA)
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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(res)
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return NONE, nil
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}
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// Inc increments the stack Item's value by 1.
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// Returns an error if the item cannot be casted to an integer
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// or if 1 cannot be added to the item
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func Inc(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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i, 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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one, err := stack.NewInt(big.NewInt(1))
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if err != nil {
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return FAULT, err
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}
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res, err := i.Add(one)
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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(res)
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return NONE, nil
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}
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// Dec decrements the stack Item's value by 1.
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// Returns an error if the item cannot be casted to an integer
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// or if 1 cannot be subtracted to the item
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func Dec(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
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i, 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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one, err := stack.NewInt(big.NewInt(1))
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if err != nil {
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return FAULT, err
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}
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res, err := i.Sub(one)
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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(res)
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return NONE, nil
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}
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func popTwoIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, error) {
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operandA, err := ctx.Estack.PopInt()
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if err != nil {
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return nil, nil, err
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}
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operandB, err := ctx.Estack.PopInt()
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if err != nil {
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return nil, nil, err
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}
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return operandA, operandB, nil
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}
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func popTwoByteArrays(ctx *stack.Context) (*stack.ByteArray, *stack.ByteArray, error) {
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// Pop first stack item and cast as byte array
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ba1, err := ctx.Estack.PopByteArray()
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if err != nil {
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return nil, nil, err
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}
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// Pop second stack item and cast as byte array
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ba2, err := ctx.Estack.PopByteArray()
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if err != nil {
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return nil, nil, err
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}
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return ba1, ba2, nil
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}
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