test-regex: expose full regcomp() to the command line

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-regex.c

@@ -1,4 +1,21 @@
 #include "git-compat-util.h"
+#include "gettext.h"
+
+struct reg_flag {
+	const char *name;
+	int flag;
+};
+
+static struct reg_flag reg_flags[] = {
+	{ "EXTENDED",	 REG_EXTENDED	},
+	{ "NEWLINE",	 REG_NEWLINE	},
+	{ "ICASE",	 REG_ICASE	},
+	{ "NOTBOL",	 REG_NOTBOL	},
+#ifdef REG_STARTEND
+	{ "STARTEND",	 REG_STARTEND	},
+#endif
+	{ NULL, 0 }
+};
 
 static int test_regex_bug(void)
 {
@@ -21,8 +38,38 @@ static int test_regex_bug(void)
 
 int main(int argc, char **argv)
 {
+	const char *pat;
+	const char *str;
+	int flags = 0;
+	regex_t r;
+	regmatch_t m[1];
+
 	if (argc == 2 && !strcmp(argv[1], "--bug"))
 		return test_regex_bug();
-	else
-		usage("test-regex --bug");
+	else if (argc < 3)
+		usage("test-regex --bug\n"
+		      "test-regex <pattern> <string> [<options>]");
+
+	argv++;
+	pat = *argv++;
+	str = *argv++;
+	while (*argv) {
+		struct reg_flag *rf;
+		for (rf = reg_flags; rf->name; rf++)
+			if (!strcmp(*argv, rf->name)) {
+				flags |= rf->flag;
+				break;
+			}
+		if (!rf->name)
+			die("do not recognize %s", *argv);
+		argv++;
+	}
+	git_setup_gettext();
+
+	if (regcomp(&r, pat, flags))
+		die("failed regcomp() for pattern '%s'", pat);
+	if (regexec(&r, str, 1, m, 0))
+		return 1;
+
+	return 0;
 }