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106 lines
2.5 KiB
Go
106 lines
2.5 KiB
Go
// Package bytefmt contains helper methods and constants for converting to and from a human-readable byte format.
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//
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// bytefmt.ByteSize(100.5*bytefmt.MEGABYTE) // "100.5M"
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// bytefmt.ByteSize(uint64(1024)) // "1K"
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//
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package bytefmt
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import (
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"errors"
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"fmt"
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"regexp"
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"strconv"
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"strings"
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)
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const (
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BYTE = 1.0
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KILOBYTE = 1024 * BYTE
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MEGABYTE = 1024 * KILOBYTE
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GIGABYTE = 1024 * MEGABYTE
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TERABYTE = 1024 * GIGABYTE
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)
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var bytesPattern *regexp.Regexp = regexp.MustCompile(`(?i)^(-?\d+(?:\.\d+)?)([KMGT]i?B?|B)$`)
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var invalidByteQuantityError = errors.New("Byte quantity must be a positive integer with a unit of measurement like M, MB, MiB, G, GiB, or GB")
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// ByteSize returns a human-readable byte string of the form 10M, 12.5K, and so forth. The following units are available:
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// T: Terabyte
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// G: Gigabyte
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// M: Megabyte
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// K: Kilobyte
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// B: Byte
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// The unit that results in the smallest number greater than or equal to 1 is always chosen.
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func ByteSize(bytes uint64) string {
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unit := ""
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value := float32(bytes)
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switch {
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case bytes >= TERABYTE:
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unit = "T"
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value = value / TERABYTE
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case bytes >= GIGABYTE:
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unit = "G"
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value = value / GIGABYTE
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case bytes >= MEGABYTE:
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unit = "M"
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value = value / MEGABYTE
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case bytes >= KILOBYTE:
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unit = "K"
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value = value / KILOBYTE
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case bytes >= BYTE:
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unit = "B"
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case bytes == 0:
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return "0"
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}
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stringValue := fmt.Sprintf("%.1f", value)
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stringValue = strings.TrimSuffix(stringValue, ".0")
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return fmt.Sprintf("%s%s", stringValue, unit)
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}
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// ToMegabytes parses a string formatted by ByteSize as megabytes.
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func ToMegabytes(s string) (uint64, error) {
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bytes, err := ToBytes(s)
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if err != nil {
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return 0, err
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}
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return bytes / MEGABYTE, nil
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}
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// ToBytes parses a string formatted by ByteSize as bytes. Note binary-prefixed and SI prefixed units both mean a base-2 units
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// KB = K = KiB = 1024
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// MB = M = MiB = 1024 * K
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// GB = G = GiB = 1024 * M
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// TB = T = TiB = 1024 * G
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func ToBytes(s string) (uint64, error) {
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parts := bytesPattern.FindStringSubmatch(strings.TrimSpace(s))
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if len(parts) < 3 {
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return 0, invalidByteQuantityError
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}
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value, err := strconv.ParseFloat(parts[1], 64)
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if err != nil || value <= 0 {
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return 0, invalidByteQuantityError
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}
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var bytes uint64
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unit := strings.ToUpper(parts[2])
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switch unit[:1] {
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case "T":
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bytes = uint64(value * TERABYTE)
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case "G":
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bytes = uint64(value * GIGABYTE)
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case "M":
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bytes = uint64(value * MEGABYTE)
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case "K":
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bytes = uint64(value * KILOBYTE)
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case "B":
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bytes = uint64(value * BYTE)
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}
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return bytes, nil
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}
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