415e22abe2
Plumb through the standard context.Context so that a function can be cancelled if someone requests this. It makes it less awkward to write simple functions that might depend on io or network access.
92 lines
2.9 KiB
Go
92 lines
2.9 KiB
Go
// Mgmt
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// Copyright (C) 2013-2024+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//
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// Additional permission under GNU GPL version 3 section 7
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//
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// If you modify this program, or any covered work, by linking or combining it
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// with embedded mcl code and modules (and that the embedded mcl code and
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// modules which link with this program, contain a copy of their source code in
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// the authoritative form) containing parts covered by the terms of any other
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// license, the licensors of this program grant you additional permission to
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// convey the resulting work. Furthermore, the licensors of this program grant
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// the original author, James Shubin, additional permission to update this
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// additional permission if he deems it necessary to achieve the goals of this
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// additional permission.
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package coremath
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import (
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"context"
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"fmt"
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"math"
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"github.com/purpleidea/mgmt/lang/funcs/simplepoly"
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"github.com/purpleidea/mgmt/lang/types"
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)
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func init() {
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simplepoly.ModuleRegister(ModuleName, "mod", []*types.FuncValue{
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{
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T: types.NewType("func(int, int) int"),
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V: Mod,
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},
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{
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T: types.NewType("func(float, float) float"),
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V: Mod,
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},
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})
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}
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// Mod returns mod(x, y), the remainder of x/y. The two values must be either
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// both of KindInt or both of KindFloat, and it will return the same kind. If
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// you pass in a divisor of zero, this will error, eg: mod(x, 0) = NaN.
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// TODO: consider returning zero instead of erroring?
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func Mod(ctx context.Context, input []types.Value) (types.Value, error) {
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var x, y float64
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var float bool
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k := input[0].Type().Kind
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switch k {
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case types.KindFloat:
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float = true
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x = input[0].Float()
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y = input[1].Float()
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case types.KindInt:
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x = float64(input[0].Int())
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y = float64(input[1].Int())
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default:
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return nil, fmt.Errorf("unexpected kind: %s", k)
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}
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z := math.Mod(x, y)
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if math.IsNaN(z) {
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return nil, fmt.Errorf("result is not a number")
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}
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if math.IsInf(z, 1) {
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return nil, fmt.Errorf("unexpected positive infinity")
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}
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if math.IsInf(z, -1) {
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return nil, fmt.Errorf("unexpected negative infinity")
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}
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if float {
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return &types.FloatValue{
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V: z,
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}, nil
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}
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return &types.IntValue{
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V: int64(z), // XXX: does this truncate?
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}, nil
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}
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