scripts/library: add size_to_human

This function is the reverse of human_to_size, and converts integer byte
sizes to human readable SI prefixed values.

A logical extension of this might be to mimic the formatter that pacman
uses and allow a second argument to be passed in which can coerce the
size, rather than reducing until the unit count is below 1024.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/scripts/library/size_to_human.sh b/scripts/library/size_to_human.sh
new file mode 100644
index 00000000..9c0f0de2
--- /dev/null
+++ b/scripts/library/size_to_human.sh
@@ -0,0 +1,20 @@
+size_to_human() {
+	awk -v size="$1" '
+	BEGIN {
+		suffix[1] = "B"
+		suffix[2] = "KiB"
+		suffix[3] = "MiB"
+		suffix[4] = "GiB"
+		suffix[5] = "TiB"
+		count = 1
+
+		while (size > 1024) {
+			size /= 1024
+			count++
+		}
+
+		sizestr = sprintf("%.2f", size)
+		sub(/\.?0+$/, "", sizestr)
+		printf("%s %s", sizestr, suffix[count])
+	}'
+}