From 9754c1ab7ceebd41ffda5f8004e562f18006dc6c Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Mon, 21 Feb 2022 15:25:27 -0500
Subject: regex: Wrap the POSIX API in a facade

---
 regex.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 80 insertions(+), 7 deletions(-)

(limited to 'regex.c')

diff --git a/regex.c b/regex.c
index f8bd833..d5c8346 100644
--- a/regex.c
+++ b/regex.c
@@ -15,9 +15,29 @@
  ****************************************************************************/
 
 #include "regex.h"
+#include <stdbool.h>
 #include <stdlib.h>
+#include <string.h>
+
+#if BFS_WITH_ONIGURUMA
+#	include <onigposix.h>
+#else
+#	include <regex.h>
+#endif
+
+struct bfs_regex {
+	regex_t impl;
+};
+
+struct bfs_regex *bfs_regcomp(const char *expr, enum bfs_regex_type type, enum bfs_regcomp_flags flags, int *err) {
+	struct bfs_regex *regex = malloc(sizeof(*regex));
+	if (!regex) {
+		*err = REG_ESPACE;
+		return NULL;
+	}
+
+	int cflags = 0;
 
-int bfs_regcomp(regex_t *preg, const char *regex, int cflags, enum bfs_regex_type type) {
 #if BFS_WITH_ONIGURUMA
 	// Oniguruma's POSIX wrapper uses the selected default syntax when REG_EXTENDED is set
 	cflags |= REG_EXTENDED;
@@ -39,24 +59,77 @@ int bfs_regcomp(regex_t *preg, const char *regex, int cflags, enum bfs_regex_typ
 #else
 	switch (type) {
 	case BFS_REGEX_POSIX_BASIC:
-		cflags &= ~REG_EXTENDED;
 		break;
 	case BFS_REGEX_POSIX_EXTENDED:
 		cflags |= REG_EXTENDED;
 		break;
 	default:
-		return REG_BADPAT;
+		*err = REG_BADPAT;
+		goto fail;
+	}
+#endif
+
+	if (flags & BFS_REGEX_ICASE) {
+		cflags |= REG_ICASE;
+	}
+
+	*err = regcomp(&regex->impl, expr, cflags);
+	if (*err != 0) {
+		goto fail;
+	}
+
+	return regex;
+
+fail:
+	free(regex);
+	return NULL;
+}
+
+bool bfs_regexec(struct bfs_regex *regex, const char *str, enum bfs_regexec_flags flags, int *err) {
+	size_t len = strlen(str);
+	regmatch_t match = {
+		.rm_so = 0,
+		.rm_eo = len,
+	};
+
+	int eflags = 0;
+#ifdef REG_STARTEND
+	if (flags & BFS_REGEX_ANCHOR) {
+		eflags |= REG_STARTEND;
 	}
 #endif
 
-	return regcomp(preg, regex, cflags);
+	int ret = regexec(&regex->impl, str, 1, &match, eflags);
+	if (ret == 0) {
+		*err = 0;
+		if (flags & BFS_REGEX_ANCHOR) {
+			return match.rm_so == 0 && (size_t)match.rm_eo == len;
+		} else {
+			return true;
+		}
+	} else if (ret == REG_NOMATCH) {
+		*err = 0;
+		return false;
+	} else {
+		*err = ret;
+		return false;
+	}
+}
+
+void bfs_regfree(struct bfs_regex *regex) {
+	if (regex) {
+		regfree(&regex->impl);
+		free(regex);
+	}
 }
 
-char *bfs_regerror(int err, const regex_t *regex) {
-	size_t len = regerror(err, regex, NULL, 0);
+char *bfs_regerror(int err, const struct bfs_regex *regex) {
+	const regex_t *impl = regex ? &regex->impl : NULL;
+
+	size_t len = regerror(err, impl, NULL, 0);
 	char *str = malloc(len);
 	if (str) {
-		regerror(err, regex, str, len);
+		regerror(err, impl, str, len);
 	}
 	return str;
 }
-- 
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