grokify/mogo

package number

import (
    "errors"
    "math"
    "sort"
    "strconv"

    "golang.org/x/exp/constraints"
)

// SliceToFloat64 converts a slice of integers or floats to float64.
func SliceToFloat64[T constraints.Integer | constraints.Float](src []T) []float64 {
    var out []float64
    for _, in := range src {
        out = append(out, float64(in))
    }
    return out
}

func IntSliceDedupe(elems []int, sortElems bool) []int {
    if len(elems) == 0 {
        return elems
    }
    var deduped []int
    mapInts := map[int]int{}
    for _, el := range elems {
        if _, ok := mapInts[el]; !ok {
            deduped = append(deduped, el)
            mapInts[el] = 1
        }
    }
    if sortElems {
        sort.Ints(deduped)
    }
    return deduped
}

func IntLength[I int | int8 | int16 | int32 | int64](num I) uint {
    return uint(len(strconv.Itoa(int(num))))
}

var ErrOverflow = errors.New("integer overflow")

func Int32(i int) (int32, error) {
    if i > math.MaxInt32 || i < math.MinInt32 {
        return 0, ErrOverflow
    }
    return int32(i), nil
}

func Int16(i int) (int16, error) {
    if i > math.MaxInt16 || i < math.MinInt16 {
        return 0, ErrOverflow
    }
    return int16(i), nil
}

func Int8(i int) (int8, error) {
    if i > math.MaxInt8 || i < math.MinInt8 {
        return 0, ErrOverflow
    }
    return int8(i), nil
}

/*
// fmtInt formats v into the tail of buf.
// It returns the index where the output begins.
func fmtInt(buf []byte, v uint64) int {
    w := len(buf)
    if v == 0 {
        w--
        buf[w] = '0'
    } else {
        for v > 0 {
            w--
            buf[w] = byte(v%10) + '0'
            v /= 10
        }
    }
    return w
}
*/

// SliceIntBuildBeginEnd returns of slice of integers from beginning to end, inclusive.
func SliceIntBuildBeginEnd(beg, end int) []int {
    if beg > end {
        return []int{}
    } else if beg == end {
        return []int{beg}
    }
    var out []int
    for i := beg; i <= end; i++ {
        out = append(out, i)
    }
    return out
}