Issue #7462: Implement the stringlib fast search algorithm for the `rfind`,

`rindex`, `rsplit` and `rpartition` methods.  Patch by Florent Xicluna.

1 files changed, 14 insertions, 18 deletions

diff --git a/Objects/stringlib/find.h b/Objects/stringlib/find.h
index fbe99c7..b5bace7 100644
--- a/Objects/stringlib/find.h
+++ b/Objects/stringlib/find.h
@@ -32,20 +32,19 @@ stringlib_rfind(const STRINGLIB_CHAR* str, Py_ssize_t str_len,
                 const STRINGLIB_CHAR* sub, Py_ssize_t sub_len,
                 Py_ssize_t offset)
 {
-    /* XXX - create reversefastsearch helper! */
-    if (sub_len == 0) {
-        if (str_len < 0)
-            return -1;
-	return str_len + offset;
-    } else {
-	Py_ssize_t j, pos = -1;
-	for (j = str_len - sub_len; j >= 0; --j)
-            if (STRINGLIB_CMP(str+j, sub, sub_len) == 0) {
-                pos = j + offset;
-                break;
-            }
-        return pos;
-    }
+    Py_ssize_t pos;
+
+    if (str_len < 0)
+        return -1;
+    if (sub_len == 0)
+        return str_len + offset;
+
+    pos = fastsearch(str, str_len, sub, sub_len, FAST_RSEARCH);
+
+    if (pos >= 0)
+        pos += offset;
+
+    return pos;
 }
 
 Py_LOCAL_INLINE(Py_ssize_t)
@@ -64,10 +63,7 @@ stringlib_find_slice(const STRINGLIB_CHAR* str, Py_ssize_t str_len,
     if (end < 0)
         end = 0;
 
-    return stringlib_find(
-        str + start, end - start,
-        sub, sub_len, start
-        );
+    return stringlib_find(str + start, end - start, sub, sub_len, start);
 }
 
 Py_LOCAL_INLINE(Py_ssize_t)