bpo-46848: Use stringlib/fastsearch in mmap (GH-31625)

Speed up mmap.find(). Add _PyBytes_Find() and _PyBytes_ReverseFind().

1 files changed, 19 insertions, 0 deletions

diff --git a/Include/cpython/bytesobject.h b/Include/cpython/bytesobject.h
index 6b3f552..38a0fe0 100644
--- a/Include/cpython/bytesobject.h
+++ b/Include/cpython/bytesobject.h
@@ -116,3 +116,22 @@ PyAPI_FUNC(void*) _PyBytesWriter_WriteBytes(_PyBytesWriter *writer,
     void *str,
     const void *bytes,
     Py_ssize_t size);
+
+/* Substring Search.
+
+   Returns the index of the first occurence of
+   a substring ("needle") in a larger text ("haystack").
+   If the needle is not found, return -1.
+   If the needle is found, add offset to the index.
+*/
+
+PyAPI_FUNC(Py_ssize_t)
+_PyBytes_Find(const char *haystack, Py_ssize_t len_haystack,
+              const char *needle, Py_ssize_t len_needle,
+              Py_ssize_t offset);
+
+/* Same as above, but search right-to-left */
+PyAPI_FUNC(Py_ssize_t)
+_PyBytes_ReverseFind(const char *haystack, Py_ssize_t len_haystack,
+                     const char *needle, Py_ssize_t len_needle,
+                     Py_ssize_t offset);