Add proper option parsing to chardiff

3 files changed, 66 insertions, 4 deletions

diff --git a/chardiff.sh b/chardiff.sh
index 7d885b9..c79a102 100644
--- a/chardiff.sh
+++ b/chardiff.sh
@@ -1,7 +1,67 @@
 #!/bin/bash
 
-file1=${1?usage: chardiff FILE1 FILE2 [FLAGS]}
-file2=${2?usage: chardiff FILE1 FILE2 [FLAGS]}
-shift 2
+# Basically run getopt(1) with arguments that reflect wdiff(1)'s usage
+# Except for -d|--diff-input, chardiff doesn't support that.
+wdiff_getopt() {
+	declare ifs="$IFS"
+	IFS=$'\n'
 
-wdiff "$@" <(chardiff_pre < "$file1") <(chardiff_pre < "$file2") | chardiff_post
+	declare -a wdiff_flags
+	wdiff_flags=($(
+		LC_ALL=C wdiff --help |
+		sed -rn 's/^  (-.*\S)\s\s.*/\1/p' |
+		grep -v diff-input |
+		sed -r \
+		    -e '/=/{ s/, /:\n/g; s/=.*/:/ }' \
+		    -e '/^[^=]*$/{ s/, /\n/g }'))
+	declare -a flags_o flags_l
+	flags_o=($(printf '%s\n' "${widff_flags[@]}"|sed -n 's/^-[^-]//p'))
+	flags_l=($(printf '%s\n' "${widff_flags[@]}"|sed -n 's/^--//p'))
+
+	declare o l
+	IFS=''  o="${flags_o[*]}"
+	IFS=',' l="${flags_l[*]}"
+
+	IFS=$ifs
+
+	declare args
+	args="$(getopt -n "$0" -o "$o" -l "$l" -- "$@")" || return 1
+
+	# Check the number of file arguments
+	eval set -- "$args"
+	while true; do
+		case "$1" in
+			--) shift; break;;
+			*) shift;;
+		esac
+	done
+	if [[ $# -lt 2 ]]; then
+		printf '%s: %s\n' "$0" "$(gettext 'missing file arguments')" >&2
+		return 1
+	elif [[ $# -gt 2 ]]; then
+		printf '%s: %s\n' "$0" "$(gettext 'too many file arguments')" >&2
+		return 1
+	fi
+
+	# Return the result
+	printf '%s' "$args"
+}
+
+main() {
+	# Normalize the arguments
+	declare flags
+	flags="$(wdiff_getopt "$@")" || { wdiff --help >&2; return 1; }
+	eval set -- "$flags"
+
+	# Run wdiff with our filters
+	declare -a args=("$@")
+	declare file2=${args[-1]}; unset args[-1]
+	declare file1=${args[-1]}; unset args[-1]
+	set -o pipefail
+	wdiff "${args[@]}" \
+	      <(chardiff_pre <"$file1") \
+	      <(chardiff_pre <"$file2") \
+		| chardiff_post
+}
+
+main "$@"
diff --git a/chardiff_post.c b/chardiff_post.c
index 9a71eeb..8abc3f7 100644
--- a/chardiff_post.c
+++ b/chardiff_post.c
@@ -15,4 +15,5 @@ main (int argc, char* argv[]) {
 			putchar(c);
 		}
 	}
+	return 0;
 }
diff --git a/chardiff_pre.c b/chardiff_pre.c
index baf7835..6b682bf 100644
--- a/chardiff_pre.c
+++ b/chardiff_pre.c
@@ -10,4 +10,5 @@ main (int argc, char* argv[]) {
 			default: printf("%c\n",c); break;
 		}
 	}
+	return 0;
 }