Optimisation of array initialisation and improved docdumentation etc.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@16379 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -2,6 +2,11 @@
 
 	* Source/NSThread.m: (GSPerformHolder) execute perform operations
 	in the same order in which they were submitted.
+	* Headers/GNUstep/base/GSCategories.h: Added two new macros to
+	agressively optimise the use of varargs when initialising arrays
+	etc by avoiding multiple allocation/reallocation of memory to hold
+	arrays of objects taken from the varargs list.
+	* Source/NSArray.m: Use the new macros.
 
 2003-04-04  Stephane Corthesy <stephane@sente.ch>
 

Headers/gnustep/base/GSCategories.h

@@ -1,6 +1,6 @@
 #ifndef	INCLUDED_GS_CATEGORIES_H
 #define	INCLUDED_GS_CATEGORIES_H
-/** Declaration of extension methods to standard classes
+/** Declaration of extension methods and functions for standard classes
 
    Copyright (C) 2003 Free Software Foundation, Inc.
 
@@ -87,5 +87,195 @@
 @end
 #endif
 
+
+
+#ifndef	GS_MAX_OBJECTS_FROM_STACK
+/**
+ * The number of objects to try to get from varargs into an array on
+ * the stack ... if there are more than this, use the heap.
+ */
+#define	GS_MAX_OBJECTS_FROM_STACK	128
+#endif
+
+/**
+ * <p>This is a macro designed to minimise the use of memory allocation and
+ * deallocation when you need to work with a vararg list of objects.<br />
+ * The objects are unpacked from the vararg list into two 'C' arrays and
+ * then a code fragment you specify is able to make use of them before
+ * that 'C' array is destroyed. 
+ * </p>
+ * <p>The firstObject argument is the name of the formal parameter in your
+ * method or function which precedes the ', ...' denoting variable args.
+ * </p>
+ * <p>The code argument is a piece of objective-c code to be executed to
+ * make use of the objects stored in the 'C' arrays.<br />
+ * When this code is called the unsigned integer '__count' will contain the
+ * number of objects unpacked, the pointer '__objects' will point to
+ * the first object in each pair, and the pointer '__pairs' will point
+ * to an array containing the second halves of the pairs of objects
+ * whose first halves are in '__objects'.<br />
+ * This lets you pack a list of the form 'key, value, key, value, ...'
+ * into an array of keys and an array of values.
+ * </p>
+ */
+#define GS_USEIDPAIRLIST(firstObject, code...) ({\
+  va_list	__ap; \
+  unsigned int	__max = GS_MAX_OBJECTS_FROM_STACK; \
+  unsigned int	__count = 0; \
+  id		__buf[__max/2]; \
+  id		*__objects = __buf; \
+  if (isPaired == YES) \
+    { \
+      id		__buf2[__max/2]; \
+      id		*__pairs = __buf2; \
+      while (__count < __max) \
+	{ \
+	  id	__tmp = va_arg(__ap, id); \
+	  if (__tmp == nil) \
+	    { \
+	      break; \
+	    } \
+	  if ((__count % 2) == 0) \
+	    { \
+	      __objects[__count/2] = __tmp; \
+	    } \
+	  else \
+	    { \
+	      __pairs[__count/2] = __tmp; \
+	    } \
+	  if (++__count == __max) \
+	    { \
+	      __tmp = va_arg(__ap, id); \
+	      while (__tmp != nil) \
+		{ \
+		  __count++; \
+		  __tmp = va_arg(__ap, id); \
+		} \
+	    } \
+	  else if ((__count % 2) == 1) \
+	    { \
+	      __count++; \
+	      __pairs[__count/2] = nil; \
+	    } \
+	} \
+      va_end(__ap); \
+      if (__count > __max) \
+	{ \
+	  unsigned int	__tmp; \
+	  if ((__count % 2) == 1) __count++; \
+	  __objects = (id*)objc_malloc(__count*sizeof(id)*2); \
+	  __pairs = &__objects[__count/2]; \
+	  va_start(__ap, firstObject); \
+	  for (__tmp = 0; __tmp < __count; __tmp++) \
+	    { \
+	      if ((__count % 2) == 0) \
+		{ \
+		  __objects[__count/2] = va_arg(__ap, id); \
+		} \
+	      else \
+		{ \
+		  __pairs[__count/2] = va_arg(__ap, id); \
+		} \
+	    } \
+	  va_end(__ap); \
+	} \
+      code; \
+      if (__objects != __buf) objc_free(__objects); \
+    } \
+  else \
+    { \
+      va_start(__ap, firstObject); \
+      while (__count < __max) \
+	{ \
+	  __objects[__count] = va_arg(__ap, id); \
+	  if (__objects[__count] == nil) \
+	    { \
+	      break; \
+	    } \
+	  if (++__count == __max) \
+	    { \
+	      id	__tmp = va_arg(__ap, id); \
+	      while (__tmp != nil) \
+		{ \
+		  __count++; \
+		  __tmp = va_arg(__ap, id); \
+		} \
+	    } \
+	} \
+      va_end(__ap); \
+      if (__count > __max) \
+	{ \
+	  unsigned int	__tmp; \
+	  __objects = (id*)objc_malloc(__count*sizeof(id)); \
+	  va_start(__ap, firstObject); \
+	  for (__tmp = 0; __tmp < __count; __tmp++) \
+	    { \
+	      __objects[__tmp] = va_arg(__ap, id); \
+	    } \
+	  va_end(__ap); \
+	} \
+      code; \
+      if (__objects != __buf) objc_free(__objects); \
+    } \
+})
+
+/**
+ * <p>This is a macro designed to minimise the use of memory allocation and
+ * deallocation when you need to work with a vararg list of objects.<br />
+ * The objects are unpacked from the vararg list into a 'C' array and
+ * then a code fragment you specify is able to make use of them before
+ * that 'C' array is destroyed. 
+ * </p>
+ * <p>The firstObject argument is the name of the formal parameter in your
+ * method or function which precedes the ', ...' denoting variable args.
+ * </p>
+ * <p>The code argument is a piece of objective-c code to be executed to
+ * make use of the objects stored in the 'C' array.<br />
+ * When this code is called the unsigned integer '__count' will contain the
+ * number of objects unpacked, and the pointer '__objects' will point to
+ * the unpacked objects.
+ * </p>
+ */
+#define GS_USEIDLIST(firstObject, code...) ({\
+  va_list	__ap; \
+  unsigned int	__max = GS_MAX_OBJECTS_FROM_STACK; \
+  unsigned int	__count = 0; \
+  id		__buf[__max]; \
+  id		*__objects = __buf; \
+  va_start(__ap, firstObject); \
+  while (__count < __max) \
+    { \
+      __objects[__count] = va_arg(__ap, id); \
+      if (__objects[__count] == nil) \
+	{ \
+	  break; \
+	} \
+      if (++__count == __max) \
+	{ \
+	  id	__tmp = va_arg(__ap, id); \
+	  while (__tmp != nil) \
+	    { \
+	      __count++; \
+	      __tmp = va_arg(__ap, id); \
+	    } \
+	} \
+    } \
+  va_end(__ap); \
+  if (__count > __max) \
+    { \
+      unsigned int	__tmp; \
+      __objects = (id*)objc_malloc(__count*sizeof(id)); \
+      va_start(__ap, firstObject); \
+      for (__tmp = 0; __tmp < __count; __tmp++) \
+	{ \
+	  __objects[__tmp] = va_arg(__ap, id); \
+	} \
+      va_end(__ap); \
+    } \
+  code; \
+  if (__objects != __buf) objc_free(__objects); \
+})
+
+
 #endif	/* NO_GNUSTEP */
 #endif	/* INCLUDED_GS_CATEGORIES_H */

Source/NSArray.m

@@ -43,6 +43,7 @@
 #include <Foundation/NSMapTable.h>
 #include <Foundation/NSLock.h>
 #include <Foundation/NSDebug.h>
+#include "gnustep/base/GSCategories.h"
 #include "GSPrivate.h"
 
 extern BOOL	GSMacOSXCompatiblePropertyLists(void);
@@ -67,13 +68,10 @@ static GSPlaceholderArray	*defaultPlaceholderArray;
 static NSMapTable		*placeholderMap;
 static NSLock			*placeholderLock;
 
-@interface	NSArray (GSPrivate)
-- (id) _initWithObjects: firstObject rest: (va_list) ap;
-@end
-
-
 /**
- * A simple, low overhead, ordered container for objects.
+ * A simple, low overhead, ordered container for objects.  All the objects
+ * in the container are retained by it.  The container may not contain nil
+ * (though it may contain [NSNull+null]).
  */
 @implementation NSArray
 
@@ -222,12 +220,11 @@ static SEL	rlSel;
  */
 + (id) arrayWithObjects: firstObject, ...
 {
-  va_list ap;
-  va_start(ap, firstObject);
-  self = [[self allocWithZone: NSDefaultMallocZone()]
-  _initWithObjects: firstObject rest: ap];
-  va_end(ap);
-  return AUTORELEASE(self);
+  id	a = [self allocWithZone: NSDefaultMallocZone()];
+
+  GS_USEIDLIST(firstObject,
+    a = [a initWithObjects: __objects count: __count]); 
+  return AUTORELEASE(a);
 }
 
 /**
@@ -611,63 +608,14 @@ static SEL	rlSel;
   return nil;
 }
 
-- (id) _initWithObjects: firstObject rest: (va_list) ap
-{
-  register	unsigned		i;
-  register	unsigned		curSize;
-  auto		unsigned		prevSize;
-  auto		unsigned		newSize;
-  auto		id			*objsArray;
-  auto		id			tmpId;
-
-  /*	Do initial allocation.	*/
-  prevSize = 3;
-  curSize  = 5;
-  objsArray = (id*)NSZoneMalloc(NSDefaultMallocZone(), sizeof(id) * curSize);
-  tmpId = firstObject;
-
-  /*	Loop through adding objects to array until a nil is
-   *	found.
-   */
-  for (i = 0; tmpId != nil; i++)
-    {
-      /*	Put id into array.	*/
-      objsArray[i] = tmpId;
-
-      /*	If the index equals the current size, increase size.	*/
-      if (i == curSize - 1)
-	{
-	  /*	Fibonacci series.  Supposedly, for this application,
-	   *	the fibonacci series will be more memory efficient.
-	   */
-	  newSize  = prevSize + curSize;
-	  prevSize = curSize;
-	  curSize  = newSize;
-
-	  /*	Reallocate object array.	*/
-	  objsArray = (id*)NSZoneRealloc(NSDefaultMallocZone(), objsArray,
-	    sizeof(id) * curSize);
-	}
-      tmpId = va_arg(ap, id);
-    }
-  va_end( ap );
-
-  /*	Put object ids into NSArray.	*/
-  self = [self initWithObjects: objsArray count: i];
-  NSZoneFree(NSDefaultMallocZone(), objsArray);
-  return( self );
-}
-
 /**
  * Initialize the array the list of objects.
  * <br />May change the value of self before returning it.
  */
 - (id) initWithObjects: firstObject, ...
 {
-  va_list ap;
-  va_start(ap, firstObject);
-  self = [self _initWithObjects: firstObject rest: ap];
-  va_end(ap);
+  GS_USEIDLIST(firstObject,
+    self = [self initWithObjects: __objects count: __count]); 
   return self;
 }