1 files changed, 86 insertions, 0 deletions
diff --git a/bin/clamp b/bin/clamp
new file mode 100755
index 0000000..a673f72
--- /dev/null
+++ b/bin/clamp
@@ -0,0 +1,86 @@
+#!/bin/sh
+set -eu
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  clamp NUMBER MIN MAX
+		  clamp -h
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+		Options:
+		  -h, --help    show this message
+
+
+		Clamp the NUMBER between MIN and MAX.
+
+
+		Examples:
+
+		  Assert the number is within the interval:
+
+		    $ clamp 5 3 9
+		    5
+
+		  When a number is below MIN it gets clamped:
+
+		    $ clamp 1 3 9
+		    3
+
+		  When a number is above MAX it gets clamped:
+
+		    $ clamp 15 3 9
+		    9
+	EOF
+}
+
+for flag in "$@"; do
+	case "$flag" in
+		--)
+			break
+			;;
+		--help)
+			usage
+			help
+			exit
+			;;
+		*)
+			;;
+	esac
+done
+
+while getopts 'h' flag; do
+	case "$flag" in
+		h)
+			usage
+			help
+			exit
+			;;
+		*)
+			usage >&2
+			exit 2
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+
+NUMBER="${1:-}"
+MIN="${2:-}"
+MAX="${3:-}"
+
+eval "$(assert-arg "$NUMBER" 'NUMBER')"
+eval "$(assert-arg "$MIN"    'MIN')"
+eval "$(assert-arg "$MAX"    'MAX')"
+
+
+if [ "$MIN" -gt "$MAX" ]; then
+	printf 'MIN (%s) is greater then MAX (%s).\n' "$MIN" "$MAX" >&2
+	exit 2
+fi
+
+min -- "$(max -- "$NUMBER" "$MIN")" "$MAX"