diff --git a/pkg/vm/stack/Int.go b/pkg/vm/stack/Int.go index 52e6240d4..2c32a8b1d 100644 --- a/pkg/vm/stack/Int.go +++ b/pkg/vm/stack/Int.go @@ -111,3 +111,29 @@ func (i *Int) Abs() (*Int, error) { return b, nil } + +// Min returns the mininum between two integers. +func Min(a *Int, b *Int) *Int { + if a.Value().Cmp(b.Value()) == -1 { + return a + } + return b + +} + +// Max returns the maximun between two integers. +func Max(a *Int, b *Int) *Int { + if a.Value().Cmp(b.Value()) == 1 { + return a + } + return b +} + +// Within returns a bool whose value is true +// iff the value of the integer i is within the specified +// range [a,b) (left-inclusive). +func (i *Int) Within(a *Int, b *Int) bool { + // i >= a && i < b + return !(i.Value().Cmp(a.Value()) == -1) && i.Value().Cmp(b.Value()) == -1 + +} diff --git a/pkg/vm/vm_ops.go b/pkg/vm/vm_ops.go index cef46a199..bd2715d72 100644 --- a/pkg/vm/vm_ops.go +++ b/pkg/vm/vm_ops.go @@ -5,6 +5,9 @@ import "github.com/CityOfZion/neo-go/pkg/vm/stack" type stackInfo func(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) var opFunc = map[stack.Instruction]stackInfo{ + stack.MIN: Min, + stack.MAX: Max, + stack.WITHIN: Within, stack.SHR: Shr, stack.SHL: Shl, stack.INC: Inc, diff --git a/pkg/vm/vm_ops_maths.go b/pkg/vm/vm_ops_maths.go index 5cbe0552a..c1e362781 100644 --- a/pkg/vm/vm_ops_maths.go +++ b/pkg/vm/vm_ops_maths.go @@ -173,6 +173,54 @@ func Mul(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rst return NONE, nil } +// Min pops two integers, a and b, off of the stack and pushes an integer to the stack +// whose value is is the minum between a and b's value. +// Returns an error if either items cannot be casted to an integer +func Min(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) { + + operandA, operandB, err := popTwoIntegers(ctx) + if err != nil { + return FAULT, err + } + res := stack.Min(operandA, operandB) + + ctx.Estack.Push(res) + + return NONE, nil +} + +// Max pops two integers, a and b, off of the stack and pushes an integer to the stack +// whose value is is the maximum between a and b's value. +// Returns an error if either items cannot be casted to an integer +func Max(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) { + + operandA, operandB, err := popTwoIntegers(ctx) + if err != nil { + return FAULT, err + } + res := stack.Max(operandA, operandB) + + ctx.Estack.Push(res) + + return NONE, nil +} + +// Within pops three integers, a, b, and c off of the stack and pushes a boolean to the stack +// whose value is true iff c's value is within b's value (include) and a's value. +// Returns an error if at least one item cannot be casted to an boolean. +func Within(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) { + + a, b, c, err := popThreeIntegers(ctx) + if err != nil { + return FAULT, err + } + res := stack.NewBoolean(c.Within(b, a)) + + ctx.Estack.Push(res) + + return NONE, nil +} + // Abs pops an integer off of the stack and pushes its absolute value onto the stack. // Returns an error if the popped value is not an integer or if the absolute value cannot be taken func Abs(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) { @@ -247,19 +295,6 @@ func Negate(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, return NONE, nil } -func popTwoIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, error) { - operandA, err := ctx.Estack.PopInt() - if err != nil { - return nil, nil, err - } - operandB, err := ctx.Estack.PopInt() - if err != nil { - return nil, nil, err - } - - return operandA, operandB, nil -} - // Shl pops two integers, a and b, off of the stack and pushes an integer to the stack // whose value is the b's value shift to the left by a's value bits. // Returns an error if either items cannot be casted to an integer @@ -300,6 +335,36 @@ func Shr(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rst return NONE, nil } +func popTwoIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, error) { + operandA, err := ctx.Estack.PopInt() + if err != nil { + return nil, nil, err + } + operandB, err := ctx.Estack.PopInt() + if err != nil { + return nil, nil, err + } + + return operandA, operandB, nil +} + +func popThreeIntegers(ctx *stack.Context) (*stack.Int, *stack.Int, *stack.Int, error) { + operandA, err := ctx.Estack.PopInt() + if err != nil { + return nil, nil, nil, err + } + operandB, err := ctx.Estack.PopInt() + if err != nil { + return nil, nil, nil, err + } + operandC, err := ctx.Estack.PopInt() + if err != nil { + return nil, nil, nil, err + } + + return operandA, operandB, operandC, nil +} + func popTwoByteArrays(ctx *stack.Context) (*stack.ByteArray, *stack.ByteArray, error) { // Pop first stack item and cast as byte array ba1, err := ctx.Estack.PopByteArray() diff --git a/pkg/vm/vm_ops_maths_test.go b/pkg/vm/vm_ops_maths_test.go index b703751be..4671267f7 100644 --- a/pkg/vm/vm_ops_maths_test.go +++ b/pkg/vm/vm_ops_maths_test.go @@ -394,3 +394,85 @@ func TestShrOp(t *testing.T) { assert.Equal(t, int64(2), item.Value().Int64()) } + +func TestMinOp(t *testing.T) { + + v := VM{} + + a, err := stack.NewInt(big.NewInt(10)) + assert.NoError(t, err) + + b, err := stack.NewInt(big.NewInt(2)) + assert.NoError(t, err) + + ctx := stack.NewContext([]byte{}) + ctx.Estack.Push(a).Push(b) + + v.executeOp(stack.MIN, ctx) + + // Stack should have one item + assert.Equal(t, 1, ctx.Estack.Len()) + + item, err := ctx.Estack.PopInt() + assert.NoError(t, err) + + assert.Equal(t, int64(2), item.Value().Int64()) +} + +func TestMaxOp(t *testing.T) { + + v := VM{} + + a, err := stack.NewInt(big.NewInt(10)) + assert.NoError(t, err) + + b, err := stack.NewInt(big.NewInt(2)) + assert.NoError(t, err) + + ctx := stack.NewContext([]byte{}) + ctx.Estack.Push(a).Push(b) + + v.executeOp(stack.MAX, ctx) + + // Stack should have one item + assert.Equal(t, 1, ctx.Estack.Len()) + + item, err := ctx.Estack.PopInt() + assert.NoError(t, err) + + assert.Equal(t, int64(10), item.Value().Int64()) +} + +func TestWithinOp(t *testing.T) { + + v := VM{} + + a, err := stack.NewInt(big.NewInt(5)) + assert.NoError(t, err) + + b, err := stack.NewInt(big.NewInt(2)) + assert.NoError(t, err) + + c, err := stack.NewInt(big.NewInt(10)) + assert.NoError(t, err) + + ctx := stack.NewContext([]byte{}) + ctx.Estack.Push(a).Push(b).Push(c) + + // c is the first item popped. + // b is the second item popped. + // a is the third item popped. + // if a is within [b, c) we place a boolean, + // whose value is true, on top of the evaluation + // stack. Otherwise we place a boolean with + // false value. + v.executeOp(stack.WITHIN, ctx) + + // Stack should have one item + assert.Equal(t, 1, ctx.Estack.Len()) + + item, err := ctx.Estack.PopBoolean() + assert.NoError(t, err) + + assert.Equal(t, true, item.Value()) +}