From e83e113eae9e7cb3e09719bfc0ad68450faf3ecd Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 25 May 2009 23:25:38 +0100
Subject: [PATCH] [surface] Speed up cairo_surface_get_mime_data().

The number of mime-types attached to a surface is usually small,
typically zero. Therefore it is quicker to do a strcmp() against
each key in the private mime-data array than it is to intern the
string (i.e. compute a hash, search the hash table, and do a final
strcmp).
---
 src/cairo-array.c   |  8 --------
 src/cairo-surface.c | 33 ++++++++++++++++++---------------
 src/cairoint.h      |  6 ++++++
 3 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/src/cairo-array.c b/src/cairo-array.c
index 77e575ff2..fcd1246dc 100644
--- a/src/cairo-array.c
+++ b/src/cairo-array.c
@@ -352,14 +352,6 @@ _cairo_array_size (cairo_array_t *array)
     return array->size;
 }
 
-/* #cairo_user_data_array_t */
-
-typedef struct {
-    const cairo_user_data_key_t *key;
-    void *user_data;
-    cairo_destroy_func_t destroy;
-} cairo_user_data_slot_t;
-
 /**
  * _cairo_user_data_array_init:
  * @array: a #cairo_user_data_array_t
diff --git a/src/cairo-surface.c b/src/cairo-surface.c
index fc994b0cf..d42e1ef96 100644
--- a/src/cairo-surface.c
+++ b/src/cairo-surface.c
@@ -611,27 +611,30 @@ cairo_surface_get_mime_data (cairo_surface_t		*surface,
                              const unsigned char       **data,
                              unsigned int		*length)
 {
-    cairo_status_t status;
-    cairo_mime_data_t *mime_data;
+    cairo_user_data_slot_t *slots;
+    int i, num_slots;
 
     *data = NULL;
     *length = 0;
-    if (surface->status)
+    if (unlikely (surface->status))
 	return;
 
-    status = _cairo_intern_string (&mime_type, -1);
-    if (unlikely (status)) {
-	status = _cairo_surface_set_error (surface, status);
-	return;
+    /* The number of mime-types attached to a surface is usually small,
+     * typically zero. Therefore it is quicker to do a strcmp() against
+     * each key than it is to intern the string (i.e. compute a hash,
+     * search the hash table, and do a final strcmp).
+     */
+    num_slots = surface->mime_data.num_elements;
+    slots = _cairo_array_index (&surface->mime_data, 0);
+    for (i = 0; i < num_slots; i++) {
+	if (strcmp ((char *) slots[i].key, mime_type) == 0) {
+	    cairo_mime_data_t *mime_data = slots[i].user_data;
+
+	    *data = mime_data->data;
+	    *length = mime_data->length;
+	    return;
+	}
     }
-
-    mime_data = _cairo_user_data_array_get_data (&surface->mime_data,
-						 (cairo_user_data_key_t *) mime_type);
-    if (mime_data == NULL)
-	return;
-
-    *data = mime_data->data;
-    *length = mime_data->length;
 }
 slim_hidden_def (cairo_surface_get_mime_data);
 
diff --git a/src/cairoint.h b/src/cairoint.h
index d694ae41b..adc9f9212 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -312,6 +312,12 @@ _cairo_array_num_elements (cairo_array_t *array);
 cairo_private int
 _cairo_array_size (cairo_array_t *array);
 
+typedef struct {
+    const cairo_user_data_key_t *key;
+    void *user_data;
+    cairo_destroy_func_t destroy;
+} cairo_user_data_slot_t;
+
 cairo_private void
 _cairo_user_data_array_init (cairo_user_data_array_t *array);