Import backup from 2004-06-12

kernel/mm/vmm.cpp

@@ -113,7 +113,7 @@ void	*malloc(unsigned int bytes)
 	if (attempt)
 		return attempt;
 	if(vmm_moreCore(bytes))
-		return 0;			//we could not get any more heap memory
+		return NULL;			//we could not get any more heap memory
 	return vmm_getFreeChunk(bytes);
 }
 
@@ -341,12 +341,40 @@ HeapEntry *vmm_getHeapEntryByBase(unsigned int base)
 		if (!he)
 			break;
 	}
-	return 0;
+	return NULL;
+}
+
+
+// This function re-allocates memory already allocated, preserving the old contents
+//  (as long as newSize is greater than oldSize)
+void	*realloc(void *orig, unsigned int newSize)
+{
+	void *newMem;
+	if ((newMem = malloc(newSize)))
+	{
+		HeapEntry *he = vmm_getHeapEntryByBase((unsigned int) orig);
+		if (!he)
+			return NULL;	//old chunk not found / nonexistent
+		memcpy(newMem, orig, (he->size < newSize ? he->size : newSize));
+		free(orig);
+		return newMem;
+	}
+	else
+		return NULL;	//could not get mem for new chunk
+}
+
+// This function allocates and zeros memory for the given number of objects,
+//  given the size of each object
+void	*calloc(unsigned int number, unsigned int size)
+{
+	void *mem = malloc(number * size);
+	if (!mem)
+		return NULL;	//could not get memory
+	memset(mem, 0, number * size);
+	return mem;
 }
 
 
 
 
 
-
-

kernel/mm/vmm.h

@@ -48,6 +48,8 @@ void	vmm_addHeapEntryBlock();
 int	vmm_moreCore(unsigned int bytes);
 void	vmm_coalesceHeapEntry(HeapEntry *he);
 HeapEntry *vmm_getHeapEntryByBase(unsigned int base);
+void	*realloc(void *orig, unsigned int newSize);
+void	*calloc(unsigned int number, unsigned int size);
 
 #endif