/
size.go
105 lines (88 loc) · 2.65 KB
/
size.go
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package utils
import (
"fmt"
"regexp"
"strconv"
"strings"
)
// See: http://en.wikipedia.org/wiki/Binary_prefix
const (
// Decimal
KB = 1000
MB = 1000 * KB
GB = 1000 * MB
TB = 1000 * GB
PB = 1000 * TB
// Binary
KiB = 1024
MiB = 1024 * KiB
GiB = 1024 * MiB
TiB = 1024 * GiB
PiB = 1024 * TiB
)
type unitMap map[string]int64
var (
decimalMap = unitMap{"k": KB, "m": MB, "g": GB, "t": TB, "p": PB}
binaryMap = unitMap{"k": KiB, "m": MiB, "g": GiB, "t": TiB, "p": PiB}
sizeRegex = regexp.MustCompile(`^(\d+(\.\d+)*) ?([kKmMgGtTpP])?[iI]?[bB]?$`)
)
var decimapAbbrs = []string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}
var binaryAbbrs = []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"}
func getSizeAndUnit(size float64, base float64, _map []string) (float64, string) {
i := 0
unitsLimit := len(_map) - 1
for size >= base && i < unitsLimit {
size = size / base
i++
}
return size, _map[i]
}
// CustomSize returns a human-readable approximation of a size
// using custom format.
func CustomSize(format string, size float64, base float64, _map []string) string {
size, unit := getSizeAndUnit(size, base, _map)
return fmt.Sprintf(format, size, unit)
}
// ToDecimalSizeStringWithPrecision allows the size to be in any precision,
func ToDecimalSizeStringWithPrecision(size float64, precision int) string {
size, unit := getSizeAndUnit(size, 1000.0, decimapAbbrs)
return fmt.Sprintf("%.*g%s", precision, size, unit)
}
// ToDecimalSizeString with 2 decimal
func ToDecimalSizeString(size float64) string {
return ToDecimalSizeStringWithPrecision(size, 2)
}
// ToBinarySizeString returns a human-readable size in bytes, kibibytes,
// mebibytes, gibibytes, or tebibytes (eg. "44kiB", "17MiB").
func ToBinarySizeString(size float64) string {
return CustomSize("%.4g%s", size, 1024.0, binaryAbbrs)
}
// ParseSizeWithDefault returns with default
func ParseSizeWithDefault(size string, defaultSize int64) int64 {
parsed, err := ParseSize(size)
if err != nil {
return defaultSize
}
return parsed
}
// ParseSize returns an integer from a human-readable specification of a
// size using SI standard (eg. "44kB", "17MB", "17MiB").
func ParseSize(sizeStr string) (int64, error) {
matches := sizeRegex.FindStringSubmatch(sizeStr)
if len(matches) != 4 {
return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
}
size, err := strconv.ParseFloat(matches[1], 64)
if err != nil {
return -1, err
}
unitPrefix := strings.ToLower(matches[3])
unitMap := decimalMap
if strings.Contains(strings.ToLower(matches[0]), "i") {
unitMap = binaryMap
}
if mul, found := unitMap[unitPrefix]; found {
size *= float64(mul)
}
return int64(size), nil
}