hugo/tpl/math/math.go
2024-01-28 23:14:09 +01:00

266 lines
7.3 KiB
Go

// Copyright 2017 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package math provides template functions for mathematical operations.
package math
import (
"errors"
"fmt"
"math"
"math/rand"
"reflect"
"sync/atomic"
_math "github.com/gohugoio/hugo/common/math"
"github.com/spf13/cast"
)
var (
errMustTwoNumbersError = errors.New("must provide at least two numbers")
errMustOneNumberError = errors.New("must provide at least one number")
)
// New returns a new instance of the math-namespaced template functions.
func New() *Namespace {
return &Namespace{}
}
// Namespace provides template functions for the "math" namespace.
type Namespace struct{}
// Abs returns the absolute value of n.
func (ns *Namespace) Abs(n any) (float64, error) {
af, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("the math.Abs function requires a numeric argument")
}
return math.Abs(af), nil
}
// Add adds the multivalued addends n1 and n2 or more values.
func (ns *Namespace) Add(inputs ...any) (any, error) {
return ns.doArithmetic(inputs, '+')
}
// Ceil returns the least integer value greater than or equal to n.
func (ns *Namespace) Ceil(n any) (float64, error) {
xf, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("Ceil operator can't be used with non-float value")
}
return math.Ceil(xf), nil
}
// Div divides n1 by n2.
func (ns *Namespace) Div(inputs ...any) (any, error) {
return ns.doArithmetic(inputs, '/')
}
// Floor returns the greatest integer value less than or equal to n.
func (ns *Namespace) Floor(n any) (float64, error) {
xf, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("Floor operator can't be used with non-float value")
}
return math.Floor(xf), nil
}
// Log returns the natural logarithm of the number n.
func (ns *Namespace) Log(n any) (float64, error) {
af, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("Log operator can't be used with non integer or float value")
}
return math.Log(af), nil
}
// Max returns the greater of all numbers in inputs. Any slices in inputs are flattened.
func (ns *Namespace) Max(inputs ...any) (maximum float64, err error) {
return ns.applyOpToScalarsOrSlices("Max", math.Max, inputs...)
}
// Min returns the smaller of all numbers in inputs. Any slices in inputs are flattened.
func (ns *Namespace) Min(inputs ...any) (minimum float64, err error) {
return ns.applyOpToScalarsOrSlices("Min", math.Min, inputs...)
}
// Sum returns the sum of all numbers in inputs. Any slices in inputs are flattened.
func (ns *Namespace) Sum(inputs ...any) (sum float64, err error) {
fn := func(x, y float64) float64 {
return x + y
}
return ns.applyOpToScalarsOrSlices("Sum", fn, inputs...)
}
// Product returns the product of all numbers in inputs. Any slices in inputs are flattened.
func (ns *Namespace) Product(inputs ...any) (product float64, err error) {
fn := func(x, y float64) float64 {
return x * y
}
return ns.applyOpToScalarsOrSlices("Product", fn, inputs...)
}
// Mod returns n1 % n2.
func (ns *Namespace) Mod(n1, n2 any) (int64, error) {
ai, erra := cast.ToInt64E(n1)
bi, errb := cast.ToInt64E(n2)
if erra != nil || errb != nil {
return 0, errors.New("modulo operator can't be used with non integer value")
}
if bi == 0 {
return 0, errors.New("the number can't be divided by zero at modulo operation")
}
return ai % bi, nil
}
// ModBool returns the boolean of n1 % n2. If n1 % n2 == 0, return true.
func (ns *Namespace) ModBool(n1, n2 any) (bool, error) {
res, err := ns.Mod(n1, n2)
if err != nil {
return false, err
}
return res == int64(0), nil
}
// Mul multiplies the multivalued numbers n1 and n2 or more values.
func (ns *Namespace) Mul(inputs ...any) (any, error) {
return ns.doArithmetic(inputs, '*')
}
// Pow returns n1 raised to the power of n2.
func (ns *Namespace) Pow(n1, n2 any) (float64, error) {
af, erra := cast.ToFloat64E(n1)
bf, errb := cast.ToFloat64E(n2)
if erra != nil || errb != nil {
return 0, errors.New("Pow operator can't be used with non-float value")
}
return math.Pow(af, bf), nil
}
// Rand returns, as a float64, a pseudo-random number in the half-open interval [0.0,1.0).
func (ns *Namespace) Rand() float64 {
return rand.Float64()
}
// Round returns the integer nearest to n, rounding half away from zero.
func (ns *Namespace) Round(n any) (float64, error) {
xf, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("Round operator can't be used with non-float value")
}
return _round(xf), nil
}
// Sqrt returns the square root of the number n.
func (ns *Namespace) Sqrt(n any) (float64, error) {
af, err := cast.ToFloat64E(n)
if err != nil {
return 0, errors.New("Sqrt operator can't be used with non integer or float value")
}
return math.Sqrt(af), nil
}
// Sub subtracts multivalued.
func (ns *Namespace) Sub(inputs ...any) (any, error) {
return ns.doArithmetic(inputs, '-')
}
func (ns *Namespace) applyOpToScalarsOrSlices(opName string, op func(x, y float64) float64, inputs ...any) (result float64, err error) {
var i int
var hasValue bool
for _, input := range inputs {
var values []float64
var isSlice bool
values, isSlice, err = ns.toFloatsE(input)
if err != nil {
err = fmt.Errorf("%s operator can't be used with non-float values", opName)
return
}
hasValue = hasValue || len(values) > 0 || isSlice
for _, value := range values {
i++
if i == 1 {
result = value
continue
}
result = op(result, value)
}
}
if !hasValue {
err = errMustOneNumberError
return
}
return
}
func (ns *Namespace) toFloatsE(v any) ([]float64, bool, error) {
vv := reflect.ValueOf(v)
switch vv.Kind() {
case reflect.Slice, reflect.Array:
var floats []float64
for i := 0; i < vv.Len(); i++ {
f, err := cast.ToFloat64E(vv.Index(i).Interface())
if err != nil {
return nil, true, err
}
floats = append(floats, f)
}
return floats, true, nil
default:
f, err := cast.ToFloat64E(v)
if err != nil {
return nil, false, err
}
return []float64{f}, false, nil
}
}
func (ns *Namespace) doArithmetic(inputs []any, operation rune) (value any, err error) {
if len(inputs) < 2 {
return nil, errMustTwoNumbersError
}
value = inputs[0]
for i := 1; i < len(inputs); i++ {
value, err = _math.DoArithmetic(value, inputs[i], operation)
if err != nil {
return
}
}
return
}
var counter uint64
// Counter increments and returns a global counter.
// This was originally added to be used in tests where now.UnixNano did not
// have the needed precision (especially on Windows).
// Note that given the parallel nature of Hugo, you cannot use this to get sequences of numbers,
// and the counter will reset on new builds.
// <docsmeta>{"identifiers": ["now.UnixNano"] }</docsmeta>
func (ns *Namespace) Counter() uint64 {
return atomic.AddUint64(&counter, uint64(1))
}