package units 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])?[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) } // HumanSizeWithPrecision allows the size to be in any precision, // instead of 4 digit precision used in units.HumanSize. func HumanSizeWithPrecision(size float64, precision int) string { size, unit := getSizeAndUnit(size, 1000.0, decimapAbbrs) return fmt.Sprintf("%.*g%s", precision, size, unit) } // HumanSize returns a human-readable approximation of a size // capped at 4 valid numbers (eg. "2.746 MB", "796 KB"). func HumanSize(size float64) string { return HumanSizeWithPrecision(size, 4) } // BytesSize returns a human-readable size in bytes, kibibytes, // mebibytes, gibibytes, or tebibytes (eg. "44kiB", "17MiB"). func BytesSize(size float64) string { return CustomSize("%.4g%s", size, 1024.0, binaryAbbrs) } // FromHumanSize returns an integer from a human-readable specification of a // size using SI standard (eg. "44kB", "17MB"). func FromHumanSize(size string) (int64, error) { return parseSize(size, decimalMap) } // RAMInBytes parses a human-readable string representing an amount of RAM // in bytes, kibibytes, mebibytes, gibibytes, or tebibytes and // returns the number of bytes, or -1 if the string is unparseable. // Units are case-insensitive, and the 'b' suffix is optional. func RAMInBytes(size string) (int64, error) { return parseSize(size, binaryMap) } // Parses the human-readable size string into the amount it represents. func parseSize(sizeStr string, uMap unitMap) (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]) if mul, ok := uMap[unitPrefix]; ok { size *= float64(mul) } return int64(size), nil }