Optimize UTF8 and Latin1 decoding

Cache a pointer to a fast decoding function when the connection encoding
is set so skip a repeated codec lookup for every string.

1 files changed, 29 insertions, 0 deletions

diff --git a/psycopg/connection_int.c b/psycopg/connection_int.c
index 43d0fda..62976d4 100644
--- a/psycopg/connection_int.c
+++ b/psycopg/connection_int.c
@@ -361,6 +361,31 @@ exit:
     return rv;
 }
 
+
+/* set fast access functions according to the currently selected codec
+ */
+void
+conn_set_fast_codec(connectionObject *self)
+{
+    Dprintf("conn_set_fast_codec: codec=%s", self->codec);
+
+    if (0 == strcmp(self->codec, "utf_8")) {
+        Dprintf("conn_set_fast_codec: PyUnicode_DecodeUTF8");
+        self->cdecoder = PyUnicode_DecodeUTF8;
+        return;
+    }
+
+    if (0 == strcmp(self->codec, "iso8859_1")) {
+        Dprintf("conn_set_fast_codec: PyUnicode_DecodeLatin1");
+        self->cdecoder = PyUnicode_DecodeLatin1;
+        return;
+    }
+
+    Dprintf("conn_set_fast_codec: no fast codec");
+    self->cdecoder = NULL;
+}
+
+
 /* Read the client encoding from the connection.
  *
  * Store the encoding in the pgconn->encoding field and the name of the
@@ -402,6 +427,8 @@ conn_read_encoding(connectionObject *self, PGconn *pgconn)
     self->codec = codec;
     codec = NULL;
 
+    conn_set_fast_codec(self);
+
     rv = 0;
 
 exit:
@@ -1243,6 +1270,8 @@ conn_set_client_encoding(connectionObject *self, const char *enc)
         codec = NULL;
     }
 
+    conn_set_fast_codec(self);
+
     Dprintf("conn_set_client_encoding: set encoding to %s (codec: %s)",
             self->encoding, self->codec);