/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// Z_zone.c

#include "quakedef.h"

#define	DYNAMIC_SIZE	0xc000

#define	ZONEID	0x1d4a11
#define MINFRAGMENT	64

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;

/*
==============================================================================

						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.
==============================================================================
*/

memzone_t	*mainzone;

void Z_ClearZone (memzone_t *zone, int size);


/*
========================
Z_ClearZone
========================
*/
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);
}


/*
========================
Z_Free
========================
*/
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;
	}
}


/*
========================
Z_Malloc
========================
*/
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);
	Com_Memset(buf, 0, size);

	return buf;
}

void *Z_TagMalloc (int size, int tag)
{
	int		extra;
	memblock_t	*start, *rover, *new_cs, *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_cs = (memblock_t *) ((byte *)base + size );
		new_cs->size = extra;
		new_cs->tag = 0;			// free block
		new_cs->prev = base;
		new_cs->id = ZONEID;
		new_cs->next = base->next;
		new_cs->next->prev = new_cs;
		base->next = new_cs;
		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));
}


/*
========================
Z_Print
========================
*/
void Z_Print (memzone_t *zone)
{
	memblock_t	*block;
	int NumBlocks = 0;
	int Size = 0;
	
	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");
		if (block->tag)
		{
			NumBlocks++;
			Size += block->size;
		}
	}
	Con_Printf("%d blocks, %d bytes\n", NumBlocks, Size);
}


/*
========================
Z_CheckHeap
========================
*/
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");
	}
}

//============================================================================

#define	HUNK_SENTINAL	0x1df001ed

typedef struct
{
	int		sentinal;
	int		size;		// including sizeof(hunk_t), -1 = not allocated
	char	name[8];
} hunk_t;

byte	*hunk_base;
int		hunk_size;

int		hunk_low_used;
int		hunk_high_used;

qboolean	hunk_tempactive;
int		hunk_tempmark;

void R_FreeTextures (void);

/*
==============
Hunk_Check

Run consistancy and sentinal trahing checks
==============
*/
void Hunk_Check (void)
{
	hunk_t	*h;
	
	for (h = (hunk_t *)hunk_base ; (byte *)h != hunk_base + hunk_low_used ; )
	{
		if (h->sentinal != HUNK_SENTINAL)
			Sys_Error ("Hunk_Check: trahsed sentinal");
		if (h->size < 16 || h->size + (byte *)h - hunk_base > hunk_size)
			Sys_Error ("Hunk_Check: bad size");
		h = (hunk_t *)((byte *)h+h->size);
	}
}

/*
==============
Hunk_Print

If "all" is specified, every single allocation is printed.
Otherwise, allocations with the same name will be totaled up before printing.
==============
*/
void Hunk_Print (qboolean all)
{
	hunk_t	*h, *next, *endlow, *starthigh, *endhigh;
	int		count, sum;
	int		totalblocks;
	char	name[9];

	name[8] = 0;
	count = 0;
	sum = 0;
	totalblocks = 0;
	
	h = (hunk_t *)hunk_base;
	endlow = (hunk_t *)(hunk_base + hunk_low_used);
	starthigh = (hunk_t *)(hunk_base + hunk_size - hunk_high_used);
	endhigh = (hunk_t *)(hunk_base + hunk_size);

	Con_Printf ("          :%8i total hunk size\n", hunk_size);
	Con_Printf ("-------------------------\n");

	while (1)
	{
	//
	// skip to the high hunk if done with low hunk
	//
		if ( h == endlow )
		{
			Con_Printf ("-------------------------\n");
			Con_Printf ("          :%8i REMAINING\n", hunk_size - hunk_low_used - hunk_high_used);
			Con_Printf ("-------------------------\n");
			h = starthigh;
		}
		
	//
	// if totally done, break
	//
		if ( h == endhigh )
			break;

	//
	// run consistancy checks
	//
		if (h->sentinal != HUNK_SENTINAL)
			Sys_Error ("Hunk_Check: trahsed sentinal");
		if (h->size < 16 || h->size + (byte *)h - hunk_base > hunk_size)
			Sys_Error ("Hunk_Check: bad size");
			
		next = (hunk_t *)((byte *)h+h->size);
		count++;
		totalblocks++;
		sum += h->size;

	//
	// print the single block
	//
		Com_Memcpy(name, h->name, 8);
		if (all)
			Con_Printf ("%8p :%8i %8s\n",h, h->size, name);
			
	//
	// print the total
	//
		if (next == endlow || next == endhigh || 
		String::NCmp(h->name, next->name, 8) )
		{
			if (!all)
				Con_Printf ("          :%8i %8s (TOTAL)\n",sum, name);
			count = 0;
			sum = 0;
		}

		h = next;
	}

	Con_Printf ("-------------------------\n");
	Con_Printf ("%8i total blocks\n", totalblocks);
	
}

/*
===================
Hunk_AllocName
===================
*/
void *Hunk_AllocName (int size, const char *name)
{
	hunk_t	*h;
	
#ifdef PARANOID
	Hunk_Check ();
#endif

	if (size < 0)
		Sys_Error ("Hunk_Alloc: bad size: %i", size);
		
	size = sizeof(hunk_t) + ((size+15)&~15);
	
	if (hunk_size - hunk_low_used - hunk_high_used < size)
		Sys_Error ("Hunk_Alloc: failed on %i bytes",size);
	
	h = (hunk_t *)(hunk_base + hunk_low_used);
	hunk_low_used += size;

	Com_Memset(h, 0, size);
	
	h->size = size;
	h->sentinal = HUNK_SENTINAL;
	String::NCpy(h->name, name, 8);
	
	return (void *)(h+1);
}

/*
===================
Hunk_Alloc
===================
*/
void *Hunk_Alloc (int size)
{
	return Hunk_AllocName (size, "unknown");
}

int	Hunk_LowMark (void)
{
	return hunk_low_used;
}

void Hunk_FreeToLowMark (int mark)
{
	if (mark < 0 || mark > hunk_low_used)
		Sys_Error ("Hunk_FreeToLowMark: bad mark %i", mark);
	Com_Memset(hunk_base + mark, 0, hunk_low_used - mark);
	hunk_low_used = mark;
}

int	Hunk_HighMark (void)
{
	if (hunk_tempactive)
	{
		hunk_tempactive = false;
		Hunk_FreeToHighMark (hunk_tempmark);
	}

	return hunk_high_used;
}

void Hunk_FreeToHighMark (int mark)
{
	if (hunk_tempactive)
	{
		hunk_tempactive = false;
		Hunk_FreeToHighMark (hunk_tempmark);
	}
	if (mark < 0 || mark > hunk_high_used)
		Sys_Error ("Hunk_FreeToHighMark: bad mark %i", mark);
	Com_Memset(hunk_base + hunk_size - hunk_high_used, 0, hunk_high_used - mark);
	hunk_high_used = mark;
}


/*
===================
Hunk_HighAllocName
===================
*/
void *Hunk_HighAllocName (int size, const char *name)
{
	hunk_t	*h;

	if (size < 0)
		Sys_Error ("Hunk_HighAllocName: bad size: %i", size);

	if (hunk_tempactive)
	{
		Hunk_FreeToHighMark (hunk_tempmark);
		hunk_tempactive = false;
	}

#ifdef PARANOID
	Hunk_Check ();
#endif

	size = sizeof(hunk_t) + ((size+15)&~15);

	if (hunk_size - hunk_low_used - hunk_high_used < size)
	{
		Con_Printf ("Hunk_HighAlloc: failed on %i bytes\n",size);
		return NULL;
	}

	hunk_high_used += size;

	h = (hunk_t *)(hunk_base + hunk_size - hunk_high_used);

	Com_Memset(h, 0, size);
	h->size = size;
	h->sentinal = HUNK_SENTINAL;
	String::NCpy(h->name, name, 8);

	return (void *)(h+1);
}


/*
=================
Hunk_TempAlloc

Return space from the top of the hunk
=================
*/
void *Hunk_TempAlloc (int size)
{
	void	*buf;

	size = (size+15)&~15;
	
	if (hunk_tempactive)
	{
		Hunk_FreeToHighMark (hunk_tempmark);
		hunk_tempactive = false;
	}
	
	hunk_tempmark = Hunk_HighMark ();

	buf = Hunk_HighAllocName (size, "temp");

	hunk_tempactive = true;

	return buf;
}

//============================================================================

void MemPrint_f()
{
	Z_Print(mainzone);
}

static void Hunk_Print_f()
{
	Hunk_Print (true);
}

/*
========================
Memory_Init
========================
*/
void Memory_Init (void *buf, int size)
{
	int p;
	int zonesize = DYNAMIC_SIZE;

	hunk_base = (byte*)buf;
	hunk_size = size;
	hunk_low_used = 0;
	hunk_high_used = 0;
	
	p = COM_CheckParm ("-zone");
	if (p)
	{
		if (p < COM_Argc()-1)
			zonesize = String::Atoi(COM_Argv(p+1)) * 1024;
		else
			Sys_Error ("Memory_Init: you must specify a size in KB after -zone");
	}
	mainzone = (memzone_t*)Hunk_AllocName (zonesize, "zone" );
	Z_ClearZone (mainzone, zonesize);

	Cmd_AddCommand("memprint", MemPrint_f);
	Cmd_AddCommand("hunkprint", Hunk_Print_f);
}

