Add Py_HashBuffer() function (#112)

Author: vstinner

docs/api.rst

@@ -10,7 +10,7 @@ Supported Python versions:
 * Python 3.6 - 3.14
 * PyPy 2.7 and PyPy 3.6 - 3.10
 
-Python 2.7 and Python 3.4 are no longer officially supported since GitHub
+Python 2.7 and Python 3.5 are no longer officially supported since GitHub
 Actions doesn't support them anymore: only best effort support is provided.
 
 C++03 and C++11 are supported on Python 3.6 and newer.
@@ -37,6 +37,10 @@ Python 3.14
 
    See `PyBytes_Join() documentation <https://docs.python.org/dev/c-api/bytes.html#c.PyBytes_Join>`__.
 
+.. c:function:: Py_hash_t Py_HashBuffer(const void *ptr, Py_ssize_t len)
+
+   See `Py_HashBuffer() documentation <https://docs.python.org/dev/c-api/hash.html#c.Py_HashBuffer>`__.
+
 .. c:function:: int PyUnicode_Equal(PyObject *str1, PyObject *str2)
 
    See `PyUnicode_Equal() documentation <https://docs.python.org/dev/c-api/unicode.html#c.PyUnicode_Equal>`__.
@@ -83,7 +87,34 @@ Python 3.14
 
 Not supported:
 
+* ``PyConfig_Get()``
+* ``PyConfig_GetInt()``
+* ``PyConfig_Names()``
+* ``PyConfig_Set()``
+* ``PyInitConfig_AddModule()``
+* ``PyInitConfig_Create()``
+* ``PyInitConfig_Free()``
+* ``PyInitConfig_FreeStrList()``
+* ``PyInitConfig_GetError()``
+* ``PyInitConfig_GetExitCode()``
+* ``PyInitConfig_GetInt()``
+* ``PyInitConfig_GetStr()``
+* ``PyInitConfig_GetStrList()``
+* ``PyInitConfig_HasOption()``
+* ``PyInitConfig_SetInt()``
+* ``PyInitConfig_SetStr()``
+* ``PyInitConfig_SetStrList()``
+* ``PyLong_AsInt32()``
+* ``PyLong_AsInt64()``
+* ``PyLong_AsUInt32()``
+* ``PyLong_AsUInt64()``
+* ``PyLong_FromInt32()``
+* ``PyLong_FromInt64()``
+* ``PyLong_FromUInt32()``
+* ``PyLong_FromUInt64()``
+* ``PyType_GetBaseByToken()``
 * ``PyUnicodeWriter_DecodeUTF8Stateful()``
+* ``Py_InitializeFromInitConfig()``
 
 
 Python 3.13

docs/changelog.rst

@@ -5,6 +5,7 @@ Changelog
 
   * ``PyBytes_Join()``
   * ``PyUnicode_Equal()``
+  * ``Py_HashBuffer()``
 
 * 2024-07-18: Add functions:
 

pythoncapi_compat.h

@@ -1555,6 +1555,27 @@ static inline PyObject* PyBytes_Join(PyObject *sep, PyObject *iterable)
 #endif
 
 
+#if PY_VERSION_HEX < 0x030E00A0
+static inline Py_hash_t Py_HashBuffer(const void *ptr, Py_ssize_t len)
+{
+#if PY_VERSION_HEX >= 0x03000000 && !defined(PYPY_VERSION)
+    extern Py_hash_t _Py_HashBytes(const void *src, Py_ssize_t len);
+
+    return _Py_HashBytes(ptr, len);
+#else
+    Py_hash_t hash;
+    PyObject *bytes = PyBytes_FromStringAndSize((const char*)ptr, len);
+    if (bytes == NULL) {
+        return -1;
+    }
+    hash = PyObject_Hash(bytes);
+    Py_DECREF(bytes);
+    return hash;
+#endif
+}
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif

tests/test_pythoncapi_compat_cext.c

@@ -1618,6 +1618,20 @@ test_hash(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args))
     assert(imag != 0);
 #endif
 
+    // Test Py_HashBuffer()
+    {
+        PyObject *abc = PyBytes_FromString("abc");
+        if (abc == NULL) {
+            return NULL;
+        }
+        Py_hash_t hash = Py_HashBuffer(PyBytes_AS_STRING(abc),
+                                       PyBytes_GET_SIZE(abc));
+        Py_hash_t hash2 = PyObject_Hash(abc);
+        assert(hash == hash2);
+
+        Py_DECREF(abc);
+    }
+
     Py_RETURN_NONE;
 }
 
@@ -1884,6 +1898,7 @@ test_unicodewriter_format(PyObject *Py_UNUSED(self), PyObject *Py_UNUSED(args))
 static PyObject *
 test_bytes(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args))
 {
+    // Test PyBytes_Join()
     PyObject *abc = PyBytes_FromString("a b c");
     if (abc == NULL) {
         return NULL;