1 files changed, 28 insertions, 0 deletions
diff --git a/src/string/strcspn.c b/src/string/strcspn.c
new file mode 100644
index 00000000..4bbdee2e
--- /dev/null
+++ b/src/string/strcspn.c
@@ -0,0 +1,28 @@
+#include <string.h>
+#include "nonstd/assert.h"
+
+/** count non-matching characters **/
+size_t strcspn(const char *s1, const char *s2)
+{
+	size_t i = 0;
+
+	ASSERT_NONNULL(s1);
+	ASSERT_NONNULL(s2);
+
+	for (i = 0; s1[i] != '\0'; i++) {
+		if (strchr (s2, s1[i]) != NULL) {
+			break;
+		}
+	}
+
+	return i;
+}
+
+/***
+the number of characters that the beginning of
+the string ARGUMENT(s1) that are not in the string ARGUMENT(s2).
+***/
+/*
+	RETURN_ALWAYS(the number of non-matching characters);
+STDC(1)
+*/