3
0
mirror of https://github.com/ergochat/ergo.git synced 2024-11-16 00:49:32 +01:00
ergo/vendor/code.cloudfoundry.org/bytefmt/bytes.go
2020-02-12 13:19:23 -05:00

122 lines
2.8 KiB
Go

// Package bytefmt contains helper methods and constants for converting to and from a human-readable byte format.
//
// bytefmt.ByteSize(100.5*bytefmt.MEGABYTE) // "100.5M"
// bytefmt.ByteSize(uint64(1024)) // "1K"
//
package bytefmt
import (
"errors"
"strconv"
"strings"
"unicode"
)
const (
BYTE = 1 << (10 * iota)
KILOBYTE
MEGABYTE
GIGABYTE
TERABYTE
PETABYTE
EXABYTE
)
var invalidByteQuantityError = errors.New("byte quantity must be a positive integer with a unit of measurement like M, MB, MiB, G, GiB, or GB")
// ByteSize returns a human-readable byte string of the form 10M, 12.5K, and so forth. The following units are available:
// E: Exabyte
// P: Petabyte
// T: Terabyte
// G: Gigabyte
// M: Megabyte
// K: Kilobyte
// B: Byte
// The unit that results in the smallest number greater than or equal to 1 is always chosen.
func ByteSize(bytes uint64) string {
unit := ""
value := float64(bytes)
switch {
case bytes >= EXABYTE:
unit = "E"
value = value / EXABYTE
case bytes >= PETABYTE:
unit = "P"
value = value / PETABYTE
case bytes >= TERABYTE:
unit = "T"
value = value / TERABYTE
case bytes >= GIGABYTE:
unit = "G"
value = value / GIGABYTE
case bytes >= MEGABYTE:
unit = "M"
value = value / MEGABYTE
case bytes >= KILOBYTE:
unit = "K"
value = value / KILOBYTE
case bytes >= BYTE:
unit = "B"
case bytes == 0:
return "0B"
}
result := strconv.FormatFloat(value, 'f', 1, 64)
result = strings.TrimSuffix(result, ".0")
return result + unit
}
// ToMegabytes parses a string formatted by ByteSize as megabytes.
func ToMegabytes(s string) (uint64, error) {
bytes, err := ToBytes(s)
if err != nil {
return 0, err
}
return bytes / MEGABYTE, nil
}
// ToBytes parses a string formatted by ByteSize as bytes. Note binary-prefixed and SI prefixed units both mean a base-2 units
// KB = K = KiB = 1024
// MB = M = MiB = 1024 * K
// GB = G = GiB = 1024 * M
// TB = T = TiB = 1024 * G
// PB = P = PiB = 1024 * T
// EB = E = EiB = 1024 * P
func ToBytes(s string) (uint64, error) {
s = strings.TrimSpace(s)
s = strings.ToUpper(s)
i := strings.IndexFunc(s, unicode.IsLetter)
if i == -1 {
return 0, invalidByteQuantityError
}
bytesString, multiple := s[:i], s[i:]
bytes, err := strconv.ParseFloat(bytesString, 64)
if err != nil || bytes < 0 {
return 0, invalidByteQuantityError
}
switch multiple {
case "E", "EB", "EIB":
return uint64(bytes * EXABYTE), nil
case "P", "PB", "PIB":
return uint64(bytes * PETABYTE), nil
case "T", "TB", "TIB":
return uint64(bytes * TERABYTE), nil
case "G", "GB", "GIB":
return uint64(bytes * GIGABYTE), nil
case "M", "MB", "MIB":
return uint64(bytes * MEGABYTE), nil
case "K", "KB", "KIB":
return uint64(bytes * KILOBYTE), nil
case "B":
return uint64(bytes), nil
default:
return 0, invalidByteQuantityError
}
}