1 files changed, 69 insertions, 2 deletions

diff --git a/source/kit/string_ref.h b/source/kit/string_ref.h
index 38ade80..8e76d06 100644
--- a/source/kit/string_ref.h
+++ b/source/kit/string_ref.h
@@ -3,6 +3,7 @@
 
 #include "array_ref.h"
 
+#include <assert.h>
 #include <string.h>
 
 #ifdef __cplusplus
@@ -24,6 +25,68 @@ static kit_str_t kit_str(i64 size, char const *static_string) {
   return s;
 }
 
+enum {
+  KIT_STR_NOT_FOUND = -1,
+};
+
+static i64 kit_str_find(kit_str_t a, kit_str_t b) {
+  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
+         b.size >= 0 && (b.size == 0 || b.values != NULL));
+  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
+      (b.size != 0 && b.values == NULL))
+    return -1;
+  for (i64 index = 0; index + b.size <= a.size; index++)
+    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b))
+      return index;
+  return -1;
+}
+
+static i64 kit_str_find_back(kit_str_t a, kit_str_t b) {
+  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
+         b.size >= 0 && (b.size == 0 || b.values != NULL));
+  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
+      (b.size != 0 && b.values == NULL))
+    return -1;
+  for (i64 index = a.size - b.size; index >= 0; index--)
+    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b))
+      return index;
+  return -1;
+}
+
+static i64 kit_str_find_n(kit_str_t a, kit_str_t b, i64 n) {
+  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
+         b.size >= 0 && (b.size == 0 || b.values != NULL));
+  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
+      (b.size != 0 && b.values == NULL))
+    return -1;
+  i64 count = 0;
+  for (i64 index = 0; index + b.size <= a.size; index++)
+    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b)) {
+      if (count == n)
+        return index;
+      else
+        count++;
+    }
+  return -1;
+}
+
+static i64 kit_str_find_back_n(kit_str_t a, kit_str_t b, i64 n) {
+  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
+         b.size >= 0 && (b.size == 0 || b.values != NULL));
+  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
+      (b.size != 0 && b.values == NULL))
+    return -1;
+  i64 count = 0;
+  for (i64 index = a.size - b.size; index >= 0; index--)
+    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b)) {
+      if (count == n)
+        return index;
+      else
+        count++;
+    }
+  return -1;
+}
+
 //  Make a barbarian string for C standard library functions.
 //  Not thread safe.
 //  Use with caution.
@@ -57,9 +120,13 @@ static char *kit_make_bs(kit_str_t s) {
 
 #ifndef KIT_DISABLE_SHORT_NAMES
 #  define BS(...) kit_make_bs(KIT_WRAP_STR(__VA_ARGS__))
-
 #  define str_t kit_str_t
-
+#  define str kit_str
+#  define str_find kit_str_find
+#  define str_find_back kit_str_find_back
+#  define str_find_n kit_str_find_n
+#  define str_find_back_n kit_str_find_back_n
+#  define STR_NOT_FOUND KIT_STR_NOT_FOUND
 #  define SZ KIT_SZ
 #  define WRAP_BS KIT_WRAP_BS
 #  define WRAP_STR KIT_WRAP_STR