[pango] Allocate PangoScriptIter on stack.

Move the PangoScriptIter structure definition to a private header file,
so that we can embed the iterator within other structures or allocate
a local iterator on the stack. This eliminates the frequent short-lived
allocations associated with the iterator.

1 files changed, 30 insertions, 40 deletions

diff --git a/pango/pango-script.c b/pango/pango-script.c
index 862c8475..605e46e2 100644
--- a/pango/pango-script.c
+++ b/pango/pango-script.c
@@ -58,29 +58,7 @@
 #include <string.h>
 
 #include "pango-script.h"
-
-#define PAREN_STACK_DEPTH 128
-
-typedef struct _ParenStackEntry ParenStackEntry;
-
-struct _ParenStackEntry
-{
-  int pair_index;
-  PangoScript script_code;
-};
-
-struct _PangoScriptIter
-{
-  const gchar *text_start;
-  const gchar *text_end;
-
-  const gchar *script_start;
-  const gchar *script_end;
-  PangoScript script_code;
-
-  ParenStackEntry paren_stack[PAREN_STACK_DEPTH];
-  int paren_sp;
-};
+#include "pango-script-private.h"
 
 /**
  * pango_script_for_unichar:
@@ -106,6 +84,28 @@ pango_script_for_unichar (gunichar ch)
 
 /**********************************************************************/
 
+PangoScriptIter *
+_pango_script_iter_init (PangoScriptIter *iter,
+	                 const char      *text,
+			 int              length)
+{
+  iter->text_start = text;
+  if (length >= 0)
+    iter->text_end = text + length;
+  else
+    iter->text_end = text + strlen (text);
+
+  iter->script_start = text;
+  iter->script_end = text;
+  iter->script_code = PANGO_SCRIPT_COMMON;
+
+  iter->paren_sp = -1;
+
+  pango_script_iter_next (iter);
+
+  return iter;
+}
+
 /**
  * pango_script_iter_new:
  * @text: a UTF-8 string
@@ -114,7 +114,7 @@ pango_script_for_unichar (gunichar ch)
  * Create a new #PangoScriptIter, used to break a string of
  * Unicode into runs by text. No copy is made of @text, so
  * the caller needs to make sure it remains valid until
- * the iterator is freed with pango_script_iter_free ().x
+ * the iterator is freed with pango_script_iter_free().
  *
  * Return value: the new script iterator, initialized
  *  to point at the first range in the text, which should be
@@ -127,23 +127,12 @@ PangoScriptIter *
 pango_script_iter_new (const char *text,
 		       int         length)
 {
-  PangoScriptIter *iter = g_slice_new (PangoScriptIter);
-
-  iter->text_start = text;
-  if (length >= 0)
-    iter->text_end = text + length;
-  else
-    iter->text_end = text + strlen (text);
-
-  iter->script_start = text;
-  iter->script_end = text;
-  iter->script_code = PANGO_SCRIPT_COMMON;
-
-  iter->paren_sp = -1;
-
-  pango_script_iter_next (iter);
+  return _pango_script_iter_init (g_slice_new (PangoScriptIter), text, length);
+}
 
-  return iter;
+void
+_pango_script_iter_fini (PangoScriptIter *iter)
+{
 }
 
 /**
@@ -157,6 +146,7 @@ pango_script_iter_new (const char *text,
 void
 pango_script_iter_free (PangoScriptIter *iter)
 {
+  _pango_script_iter_fini (iter);
   g_slice_free (PangoScriptIter, iter);
 }