bpo-32433: Optimized HMAC digest (#5023)

The hmac module now has hmac.digest(), which provides an optimized HMAC
digest for short messages. hmac.digest() is up to three times faster
than hmac.HMAC().digest().

Signed-off-by: Christian Heimes <christian@python.org>

1 files changed, 43 insertions, 1 deletions

diff --git a/Modules/clinic/_hashopenssl.c.h b/Modules/clinic/_hashopenssl.c.h
index f08d7f3afd..cbc8638c94 100644
--- a/Modules/clinic/_hashopenssl.c.h
+++ b/Modules/clinic/_hashopenssl.c.h
@@ -54,7 +54,49 @@ exit:
 
 #endif /* (OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_SCRYPT) && !defined(LIBRESSL_VERSION_NUMBER)) */
 
+PyDoc_STRVAR(_hashlib_hmac_digest__doc__,
+"hmac_digest($module, /, key, msg, digest)\n"
+"--\n"
+"\n"
+"Single-shot HMAC");
+
+#define _HASHLIB_HMAC_DIGEST_METHODDEF    \
+    {"hmac_digest", (PyCFunction)_hashlib_hmac_digest, METH_FASTCALL|METH_KEYWORDS, _hashlib_hmac_digest__doc__},
+
+static PyObject *
+_hashlib_hmac_digest_impl(PyObject *module, Py_buffer *key, Py_buffer *msg,
+                          const char *digest);
+
+static PyObject *
+_hashlib_hmac_digest(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"key", "msg", "digest", NULL};
+    static _PyArg_Parser _parser = {"y*y*s:hmac_digest", _keywords, 0};
+    Py_buffer key = {NULL, NULL};
+    Py_buffer msg = {NULL, NULL};
+    const char *digest;
+
+    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
+        &key, &msg, &digest)) {
+        goto exit;
+    }
+    return_value = _hashlib_hmac_digest_impl(module, &key, &msg, digest);
+
+exit:
+    /* Cleanup for key */
+    if (key.obj) {
+       PyBuffer_Release(&key);
+    }
+    /* Cleanup for msg */
+    if (msg.obj) {
+       PyBuffer_Release(&msg);
+    }
+
+    return return_value;
+}
+
 #ifndef _HASHLIB_SCRYPT_METHODDEF
     #define _HASHLIB_SCRYPT_METHODDEF
 #endif /* !defined(_HASHLIB_SCRYPT_METHODDEF) */
-/*[clinic end generated code: output=1ea7d0397f38e2c2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b5b90821caf05391 input=a9049054013a1b77]*/