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https://github.com/moby/moby.git
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108 lines
2.9 KiB
Go
108 lines
2.9 KiB
Go
package units
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import (
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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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// See: http://en.wikipedia.org/wiki/Binary_prefix
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const (
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// Decimal
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KB = 1000
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MB = 1000 * KB
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GB = 1000 * MB
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TB = 1000 * GB
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PB = 1000 * TB
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// Binary
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KiB = 1024
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MiB = 1024 * KiB
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GiB = 1024 * MiB
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TiB = 1024 * GiB
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PiB = 1024 * TiB
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)
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type unitMap map[string]int64
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var (
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decimalMap = unitMap{"k": KB, "m": MB, "g": GB, "t": TB, "p": PB}
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binaryMap = unitMap{"k": KiB, "m": MiB, "g": GiB, "t": TiB, "p": PiB}
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sizeRegex = regexp.MustCompile(`^(\d+(\.\d+)*) ?([kKmMgGtTpP])?[bB]?$`)
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)
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var decimapAbbrs = []string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}
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var binaryAbbrs = []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"}
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func getSizeAndUnit(size float64, base float64, _map []string) (float64, string) {
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i := 0
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unitsLimit := len(_map) - 1
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for size >= base && i < unitsLimit {
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size = size / base
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i++
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}
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return size, _map[i]
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}
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// CustomSize returns a human-readable approximation of a size
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// using custom format.
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func CustomSize(format string, size float64, base float64, _map []string) string {
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size, unit := getSizeAndUnit(size, base, _map)
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return fmt.Sprintf(format, size, unit)
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}
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// HumanSizeWithPrecision allows the size to be in any precision,
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// instead of 4 digit precision used in units.HumanSize.
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func HumanSizeWithPrecision(size float64, precision int) string {
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size, unit := getSizeAndUnit(size, 1000.0, decimapAbbrs)
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return fmt.Sprintf("%.*g %s", precision, size, unit)
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}
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// HumanSize returns a human-readable approximation of a size
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// capped at 4 valid numbers (eg. "2.746 MB", "796 KB").
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func HumanSize(size float64) string {
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return HumanSizeWithPrecision(size, 4)
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}
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// BytesSize returns a human-readable size in bytes, kibibytes,
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// mebibytes, gibibytes, or tebibytes (eg. "44kiB", "17MiB").
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func BytesSize(size float64) string {
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return CustomSize("%.4g %s", size, 1024.0, binaryAbbrs)
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}
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// FromHumanSize returns an integer from a human-readable specification of a
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// size using SI standard (eg. "44kB", "17MB").
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func FromHumanSize(size string) (int64, error) {
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return parseSize(size, decimalMap)
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}
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// RAMInBytes parses a human-readable string representing an amount of RAM
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// in bytes, kibibytes, mebibytes, gibibytes, or tebibytes and
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// returns the number of bytes, or -1 if the string is unparseable.
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// Units are case-insensitive, and the 'b' suffix is optional.
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func RAMInBytes(size string) (int64, error) {
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return parseSize(size, binaryMap)
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}
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// Parses the human-readable size string into the amount it represents.
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func parseSize(sizeStr string, uMap unitMap) (int64, error) {
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matches := sizeRegex.FindStringSubmatch(sizeStr)
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if len(matches) != 4 {
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return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
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}
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size, err := strconv.ParseFloat(matches[1], 64)
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if err != nil {
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return -1, err
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}
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unitPrefix := strings.ToLower(matches[3])
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if mul, ok := uMap[unitPrefix]; ok {
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size *= float64(mul)
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}
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return int64(size), nil
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}
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