first commit

progress/format.go

@@ -0,0 +1,79 @@
+package progress
+
+import (
+	"fmt"
+	"time"
+)
+
+// humanSize formats a byte count by abbreviating it: divide by
+// 1024 while the value is at least one unit and a larger unit remains, then bump
+// to the next unit when the quotient is >=922 (so 0.9Mi shows instead of 922Ki).
+// The unit ladder is capped at Gi, so a terabyte prints
+// as "1024.0GiB". When human is false it prints the raw integer with a B suffix.
+func humanSize(n int64, human bool) string {
+	if !human {
+		return fmt.Sprintf("%dB", n)
+	}
+	const unit = 1024
+	if n < unit {
+		return fmt.Sprintf("%dB", n)
+	}
+	// "KMG" caps the ladder at Gi (the units {"","Ki","Mi","Gi"}).
+	const suffixes = "KMG"
+	div, exp := int64(unit), 0
+	for v := n / unit; v >= unit && exp+1 < len(suffixes); v /= unit {
+		div *= unit
+		exp++
+	}
+	// Bump to the next unit when the quotient is >=922 and a unit remains, so
+	// 922*1024 bytes reads as 0.9MiB rather than 922KiB.
+	if q := n / div; q >= 922 && exp+1 < len(suffixes) {
+		div *= unit
+		exp++
+	}
+	val := float64(n) / float64(div)
+	suffix := suffixes[exp]
+	// One decimal for small mantissas and for anything that overflowed the
+	// capped Gi unit (1024.0GiB and up); a bare integer otherwise (e.g. 20MiB).
+	if val < 10 || exp == len(suffixes)-1 && val >= unit {
+		return fmt.Sprintf("%.1f%ciB", val, suffix)
+	}
+	return fmt.Sprintf("%.0f%ciB", val, suffix)
+}
+
+// speed formats a bytes-per-second rate. The DL:/UL: fields show the bare
+// abbreviated size with no "/s" suffix.
+func speed(bytesPerSec int64, human bool) string {
+	return humanSize(bytesPerSec, human)
+}
+
+// secfmt renders a duration as "1h2m3s", appending each unit only when it is
+// nonzero (but still showing seconds when the whole input is 0):
+// 3600s->"1h", 120s->"2m", 3720s->"1h2m". A non-positive or absurd
+// duration renders as "--".
+func secfmt(d time.Duration) string {
+	s := int64(d.Seconds())
+	if s < 0 || d > 99*time.Hour {
+		return "--"
+	}
+	h, m, sec := s/3600, (s%3600)/60, s%60
+	var str string
+	if h > 0 {
+		str += fmt.Sprintf("%dh", h)
+	}
+	if m > 0 {
+		str += fmt.Sprintf("%dm", m)
+	}
+	if sec > 0 || s == 0 {
+		str += fmt.Sprintf("%ds", sec)
+	}
+	return str
+}
+
+// percent returns completed/total as a 0-100 integer, or 0 when total is unknown.
+func percent(completed, total int64) int {
+	if total <= 0 {
+		return 0
+	}
+	return int(completed * 100 / total)
+}