[cairo-pen] Embed a small array of vertices into cairo_pen_t.

Eliminate allocation of the vertex array for the common cases.

1 files changed, 44 insertions, 27 deletions

diff --git a/src/cairo-pen.c b/src/cairo-pen.c
index 37456d99f..4a882d566 100644
--- a/src/cairo-pen.c
+++ b/src/cairo-pen.c
@@ -45,15 +45,6 @@ _cairo_pen_compute_slopes (cairo_pen_t *pen);
 static void
 _cairo_pen_stroke_spline_half (cairo_pen_t *pen, cairo_spline_t *spline, cairo_direction_t dir, cairo_polygon_t *polygon);
 
-void
-_cairo_pen_init_empty (cairo_pen_t *pen)
-{
-    pen->radius = 0;
-    pen->tolerance = 0;
-    pen->vertices = NULL;
-    pen->num_vertices = 0;
-}
-
 cairo_status_t
 _cairo_pen_init (cairo_pen_t	*pen,
 		 double		 radius,
@@ -78,10 +69,14 @@ _cairo_pen_init (cairo_pen_t	*pen,
 						    radius,
 						    ctm);
 
-    pen->vertices = _cairo_malloc_ab (pen->num_vertices,
-	                              sizeof (cairo_pen_vertex_t));
-    if (pen->vertices == NULL)
-	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+    if (pen->num_vertices > ARRAY_LENGTH (pen->vertices_embedded)) {
+	pen->vertices = _cairo_malloc_ab (pen->num_vertices,
+					  sizeof (cairo_pen_vertex_t));
+	if (pen->vertices == NULL)
+	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+    } else {
+	pen->vertices = pen->vertices_embedded;
+    }
 
     /*
      * Compute pen coordinates.  To generate the right ellipse, compute points around
@@ -107,10 +102,11 @@ _cairo_pen_init (cairo_pen_t	*pen,
 void
 _cairo_pen_fini (cairo_pen_t *pen)
 {
-    free (pen->vertices);
-    pen->vertices = NULL;
+    if (pen->vertices != pen->vertices_embedded)
+	free (pen->vertices);
 
-    _cairo_pen_init_empty (pen);
+    pen->vertices = pen->vertices_embedded;
+    pen->num_vertices = 0;
 }
 
 cairo_status_t
@@ -118,13 +114,17 @@ _cairo_pen_init_copy (cairo_pen_t *pen, cairo_pen_t *other)
 {
     *pen = *other;
 
+    pen->vertices = pen->vertices_embedded;
     if (pen->num_vertices) {
-	pen->vertices = _cairo_malloc_ab (pen->num_vertices,
-	       	                          sizeof (cairo_pen_vertex_t));
-	if (pen->vertices == NULL)
-	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	if (pen->num_vertices > ARRAY_LENGTH (pen->vertices_embedded)) {
+	    pen->vertices = _cairo_malloc_ab (pen->num_vertices,
+					      sizeof (cairo_pen_vertex_t));
+	    if (pen->vertices == NULL)
+		return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	}
 
-	memcpy (pen->vertices, other->vertices, pen->num_vertices * sizeof (cairo_pen_vertex_t));
+	memcpy (pen->vertices, other->vertices,
+		pen->num_vertices * sizeof (cairo_pen_vertex_t));
     }
 
     return CAIRO_STATUS_SUCCESS;
@@ -133,18 +133,35 @@ _cairo_pen_init_copy (cairo_pen_t *pen, cairo_pen_t *other)
 cairo_status_t
 _cairo_pen_add_points (cairo_pen_t *pen, cairo_point_t *point, int num_points)
 {
-    cairo_pen_vertex_t *vertices;
     cairo_status_t status;
     int num_vertices;
     int i;
 
     num_vertices = pen->num_vertices + num_points;
-    vertices = _cairo_realloc_ab (pen->vertices,
-	                          num_vertices, sizeof (cairo_pen_vertex_t));
-    if (vertices == NULL)
-	return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+    if (num_vertices > ARRAY_LENGTH (pen->vertices_embedded) ||
+	pen->vertices != pen->vertices_embedded)
+    {
+	cairo_pen_vertex_t *vertices;
+
+	if (pen->vertices == pen->vertices_embedded) {
+	    vertices = _cairo_malloc_ab (num_vertices,
+		                         sizeof (cairo_pen_vertex_t));
+	    if (vertices == NULL)
+		return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+
+	    memcpy (vertices, pen->vertices,
+		    pen->num_vertices * sizeof (cairo_pen_vertex_t));
+	} else {
+	    vertices = _cairo_realloc_ab (pen->vertices,
+					  num_vertices,
+					  sizeof (cairo_pen_vertex_t));
+	    if (vertices == NULL)
+		return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+	}
+
+	pen->vertices = vertices;
+    }
 
-    pen->vertices = vertices;
     pen->num_vertices = num_vertices;
 
     /* initialize new vertices */