cointop/pkg/humanize/humanize.go

package humanize

import (
	"bytes"
	"strconv"
	"strings"
)

// Commaf produces a string form of the given number in base 10 with
// commas after every three orders of magnitude.
//
// e.g. Commaf(834142.32) -> 834,142.32
func Commaf(v float64) string {
	buf := &bytes.Buffer{}
	if v < 0 {
		buf.Write([]byte{'-'})
		v = 0 - v
	}

	comma := []byte{','}

	parts := strings.Split(strconv.FormatFloat(v, 'f', -1, 64), ".")
	pos := 0
	if len(parts[0])%3 != 0 {
		pos += len(parts[0]) % 3
		buf.WriteString(parts[0][:pos])
		buf.Write(comma)
	}
	for ; pos < len(parts[0]); pos += 3 {
		buf.WriteString(parts[0][pos : pos+3])
		buf.Write(comma)
	}
	buf.Truncate(buf.Len() - 1)

	if len(parts) > 1 {
		buf.Write([]byte{'.'})
		buf.WriteString(parts[1])
	}
	return buf.String()
}