zone.c gets its name back

include/QF/zone.h

@@ -96,6 +96,14 @@ Zone block
 
 void Memory_Init (void *buf, int size);
 
+void Z_Free (void *ptr);
+void *Z_Malloc (int size);			// returns 0 filled memory
+void *Z_TagMalloc (int size, int tag);
+
+void Z_DumpHeap (void);
+void Z_CheckHeap (void);
+int Z_FreeMemory (void);
+
 void *Hunk_Alloc (int size);		// returns 0 filled memory
 void *Hunk_AllocName (int size, const char *name);
 

libs/util/zone.c

@@ -54,10 +54,202 @@ void        Cache_FreeLow (int new_low_hunk);
 void        Cache_FreeHigh (int new_high_hunk);
 
 /*
+
+   						ZONE MEMORY ALLOCATION
+
+	There is never any space between memblocks, and there will never be two
+	contiguous free memblocks.
+
+	The rover can be left pointing at a non-empty block
+
 	The zone calls are pretty much only used for small strings and structures,
 	all big things are allocated on the hunk.
 */
 
+typedef struct memblock_s
+{
+	int         size;		// including the header and possibly tiny fragments
+	int         tag;		// a tag of 0 is a free block
+	int         id;			// should be ZONEID
+	struct memblock_s *next, *prev;
+	int         pad;		// pad to 64 bit boundary
+} memblock_t;
+
+typedef struct
+{
+	int         size;		// total bytes malloced, including header
+	memblock_t  blocklist;	// start / end cap for linked list
+	memblock_t  *rover;
+} memzone_t;
+
+memzone_t   *mainzone;
+
+void Z_ClearZone (memzone_t *zone, int size)
+{
+	memblock_t	*block;
+	
+	// set the entire zone to one free block
+
+	zone->blocklist.next = zone->blocklist.prev = block =
+		(memblock_t *)( (byte *)zone + sizeof(memzone_t) );
+	zone->blocklist.tag = 1;	// in use block
+	zone->blocklist.id = 0;
+	zone->blocklist.size = 0;
+	zone->rover = block;
+	
+	block->prev = block->next = &zone->blocklist;
+	block->tag = 0;			// free block
+	block->id = ZONEID;
+	block->size = size - sizeof(memzone_t);
+}
+
+
+void Z_Free (void *ptr)
+{
+	memblock_t	*block, *other;
+	
+	if (!ptr)
+		Sys_Error ("Z_Free: NULL pointer");
+
+	block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
+	if (block->id != ZONEID)
+		Sys_Error ("Z_Free: freed a pointer without ZONEID");
+	if (block->tag == 0)
+		Sys_Error ("Z_Free: freed a freed pointer");
+
+	block->tag = 0;		// mark as free
+	
+	other = block->prev;
+	if (!other->tag)
+	{	// merge with previous free block
+		other->size += block->size;
+		other->next = block->next;
+		other->next->prev = other;
+		if (block == mainzone->rover)
+			mainzone->rover = other;
+		block = other;
+	}
+	
+	other = block->next;
+	if (!other->tag)
+	{	// merge the next free block onto the end
+		block->size += other->size;
+		block->next = other->next;
+		block->next->prev = block;
+		if (other == mainzone->rover)
+			mainzone->rover = block;
+	}
+}
+
+
+void *Z_Malloc (int size)
+{
+	void	*buf;
+	
+Z_CheckHeap ();	// DEBUG
+	buf = Z_TagMalloc (size, 1);
+	if (!buf)
+		Sys_Error ("Z_Malloc: failed on allocation of %i bytes",size);
+	memset (buf, 0, size);
+
+	return buf;
+}
+
+void *Z_TagMalloc (int size, int tag)
+{
+	int		extra;
+	memblock_t	*start, *rover, *new, *base;
+
+	if (!tag)
+		Sys_Error ("Z_TagMalloc: tried to use a 0 tag");
+
+	// scan through the block list looking for the first free block
+	// of sufficient size
+	size += sizeof(memblock_t);	// account for size of block header
+	size += 4;					// space for memory trash tester
+	size = (size + 7) & ~7;		// align to 8-byte boundary
+	
+	base = rover = mainzone->rover;
+	start = base->prev;
+	
+	do
+	{
+		if (rover == start)	// scaned all the way around the list
+			return NULL;
+		if (rover->tag)
+			base = rover = rover->next;
+		else
+			rover = rover->next;
+	} while (base->tag || base->size < size);
+	
+	// found a block big enough
+	extra = base->size - size;
+	if (extra >  MINFRAGMENT)
+	{	// there will be a free fragment after the allocated block
+		new = (memblock_t *) ((byte *)base + size );
+		new->size = extra;
+		new->tag = 0;			// free block
+		new->prev = base;
+		new->id = ZONEID;
+		new->next = base->next;
+		new->next->prev = new;
+		base->next = new;
+		base->size = size;
+	}
+	
+	base->tag = tag;				// no longer a free block
+	
+	mainzone->rover = base->next;	// next allocation will start looking here
+	
+	base->id = ZONEID;
+
+	// marker for memory trash testing
+	*(int *)((byte *)base + base->size - 4) = ZONEID;
+
+	return (void *) ((byte *)base + sizeof(memblock_t));
+}
+
+
+void Z_Print (memzone_t *zone)
+{
+	memblock_t	*block;
+	
+	Con_Printf ("zone size: %i  location: %p\n",mainzone->size,mainzone);
+	
+	for (block = zone->blocklist.next ; ; block = block->next)
+	{
+		Con_Printf ("block:%p    size:%7i    tag:%3i\n",
+			block, block->size, block->tag);
+		
+		if (block->next == &zone->blocklist)
+			break;			// all blocks have been hit	
+		if ( (byte *)block + block->size != (byte *)block->next)
+			Con_Printf ("ERROR: block size does not touch the next block\n");
+		if ( block->next->prev != block)
+			Con_Printf ("ERROR: next block doesn't have proper back link\n");
+		if (!block->tag && !block->next->tag)
+			Con_Printf ("ERROR: two consecutive free blocks\n");
+	}
+}
+
+
+void Z_CheckHeap (void)
+{
+	memblock_t	*block;
+	
+	for (block = mainzone->blocklist.next ; ; block = block->next)
+	{
+		if (block->next == &mainzone->blocklist)
+			break;			// all blocks have been hit	
+		if ( (byte *)block + block->size != (byte *)block->next)
+			Sys_Error ("Z_CheckHeap: block size does not touch the next block\n");
+		if ( block->next->prev != block)
+			Sys_Error ("Z_CheckHeap: next block doesn't have proper back link\n");
+		if (!block->tag && !block->next->tag)
+			Sys_Error ("Z_CheckHeap: two consecutive free blocks\n");
+	}
+}
+
 //============================================================================
 
 typedef struct {