Format byte size as kilobytes, megabytes, gigabytes, ...

These utility functions convert a size in bytes to a human-readable string in either SI (decimal) or IEC (binary) format.

Input ByteCountSI ByteCountIEC 999 "999 B" "999 B" 1000 "1.0 kB" "1000 B" 1023 "1.0 kB" "1023 B" 1024 "1.0 kB" "1.0 KiB" 987,654,321 "987.7 MB" "941.9 MiB" math.MaxInt64 "9.2 EB" "8.0 EiB"

func ByteCountSI(b int64) string {
    const unit = 1000
    if b < unit {
        return fmt.Sprintf("%d B", b)
    }
    div, exp := int64(unit), 0
    for n := b / unit; n >= unit; n /= unit {
        div *= unit
        exp++
    }
    return fmt.Sprintf("%.1f %cB",
        float64(b)/float64(div), "kMGTPE"[exp])
}

func ByteCountIEC(b int64) string {
    const unit = 1024
    if b < unit {
        return fmt.Sprintf("%d B", b)
    }
    div, exp := int64(unit), 0
    for n := b / unit; n >= unit; n /= unit {
        div *= unit
        exp++
    }
    return fmt.Sprintf("%.1f %ciB",
        float64(b)/float64(div), "KMGTPE"[exp])
}

byte-count.go

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