1 files changed, 71 insertions, 0 deletions
diff --git a/xs_match.h b/xs_match.h
new file mode 100644
index 0000000..9f12c15
--- /dev/null
+++ b/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 */