Backport from xs.

format.c

@@ -235,7 +235,7 @@ xs_str *sanitize(const char *content)
 
             if (valid_tags[i]) {
                 /* accepted tag: rebuild it with only the accepted elements */
-                xs *el = xs_regex_match(v, "(src|href|rel|class|target)=\"[^\"]*\"");
+                xs *el = xs_regex_select(v, "(src|href|rel|class|target)=\"[^\"]*\"");
                 xs *s3 = xs_join(el, " ");
 
                 s2 = xs_fmt("<%s%s%s%s>",

snac.c

@@ -17,6 +17,7 @@
 #include "xs_time.h"
 #include "xs_glob.h"
 #include "xs_random.h"
+#include "xs_match.h"
 
 #include "snac.h"
 

xs_match.h

@@ -0,0 +1,71 @@
+/* copyright (c) 2022 - 2023 grunfink et al. / MIT license */
+
+#ifndef _XS_MATCH_H
+
+#define _XS_MATCH_H
+
+/* spec is very similar to shell file globbing:
+   an * matches anything;
+   a ? matches any character;
+   | select alternative strings to match;
+   a \\ escapes a special character;
+   any other char matches itself. */
+
+int xs_match(const char *str, const char *spec);
+
+#ifdef XS_IMPLEMENTATION
+
+int xs_match(const char *str, const char *spec)
+{
+    const char *o_str = str;
+
+again:
+    if (*spec == '*') {
+        spec++;                 /* wildcard */
+
+        do {
+            if (xs_match(str, spec))
+                return 1;
+            str++;
+        } while (*str);
+
+        return 0;
+    }
+
+    if (*spec == '?' && *str) {
+        spec++;                 /* any character */
+        str++;
+        goto again;
+    }
+
+    if (*spec == '|')
+        return 1;               /* alternative separator? positive match */
+
+    if (!*spec)
+        return 1;               /* end of spec? positive match */
+
+    if (*spec == '\\')
+        spec++;                 /* escaped char */
+
+    if (*spec == *str) {
+        spec++;                 /* matched 1 char */
+        str++;
+        goto again;
+    }
+
+    /* not matched; are there any alternatives? */
+    while (*spec) {
+        if (*spec == '|')
+            return xs_match(o_str, spec + 1);   /* try next alternative */
+
+        if (*spec == '\\')
+            spec++;             /* escaped char */
+        spec++;
+    }
+
+    return 0;
+}
+
+#endif /* XS_IMPLEMENTATION */
+
+#endif /* XS_MATCH_H */

xs_regex.h

@@ -6,8 +6,8 @@
 
 xs_list *xs_regex_split_n(const char *str, const char *rx, int count);
 #define xs_regex_split(str, rx) xs_regex_split_n(str, rx, XS_ALL)
-xs_list *xs_regex_match_n(const char *str, const char *rx, int count);
+xs_list *xs_regex_select_n(const char *str, const char *rx, int count);
-#define xs_regex_match(str, rx) xs_regex_match_n(str, rx, XS_ALL)
+#define xs_regex_select(str, rx) xs_regex_select_n(str, rx, XS_ALL)
 xs_list *xs_regex_replace_in(xs_str *str, const char *rx, const char *rep, int count);
 #define xs_regex_replace_i(str, rx, rep) xs_regex_replace_in(str, rx, rep, XS_ALL)
 #define xs_regex_replace_n(str, rx, rep, count) xs_regex_replace_in(xs_dup(str), rx, rep, count)
@@ -55,8 +55,8 @@ xs_list *xs_regex_split_n(const char *str, const char *rx, int count)
 }
 
 
-xs_list *xs_regex_match_n(const char *str, const char *rx, int count)
+xs_list *xs_regex_select_n(const char *str, const char *rx, int count)
-/* returns a list with upto count matches */
+/* selects all matches and return them as a list */
 {
     xs_list *list = xs_list_new();
     xs *split = NULL;

xs_version.h

@@ -1 +1 @@
-/* 0ca53ca2b1c34efa95639d2a0f5bf4bd32f8958c */
+/* 06767a70773865042a70680aef50f7ecb077681a */