pkg/units/size.go
unclejack bce8f57f1b pkg/units: lint
Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
2014-10-06 22:19:41 +03:00

83 lines
1.9 KiB
Go

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+)([kKmMgGtTpP])?[bB]?$`)
)
var unitAbbrs = [...]string{"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}
// HumanSize returns a human-readable approximation of a size
// using SI standard (eg. "44kB", "17MB")
func HumanSize(size int64) string {
i := 0
sizef := float64(size)
for sizef >= 1000.0 {
sizef = sizef / 1000.0
i++
}
return fmt.Sprintf("%.4g %s", sizef, unitAbbrs[i])
}
// 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) != 3 {
return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
}
size, err := strconv.ParseInt(matches[1], 10, 0)
if err != nil {
return -1, err
}
unitPrefix := strings.ToLower(matches[2])
if mul, ok := uMap[unitPrefix]; ok {
size *= mul
}
return size, nil
}