1 files changed, 29 insertions, 0 deletions
diff --git a/missing/strstr.c b/missing/strstr.c
new file mode 100644
index 0000000000..e6613c5d2f
--- /dev/null
+++ b/missing/strstr.c
@@ -0,0 +1,29 @@
+/* public domain rewrite of strstr(3) */
+
+#include "ruby/missing.h"
+
+size_t strlen(const char*);
+
+char *
+strstr(const char *haystack, const char *needle)
+{
+    const char *hend;
+    const char *a, *b;
+
+    if (*needle == 0) return (char *)haystack;
+    hend = haystack + strlen(haystack) - strlen(needle) + 1;
+    while (haystack < hend) {
+	if (*haystack == *needle) {
+	    a = haystack;
+	    b = needle;
+	    for (;;) {
+		if (*b == 0) return (char *)haystack;
+		if (*a++ != *b++) {
+		    break;
+		}
+	    }
+	}
+	haystack++;
+    }
+    return 0;
+}