/*
Copyright (C) 1994-1995 Apogee Software, Ltd.

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 <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef DOS
#include <dos.h>
#include <conio.h>
#endif

#include "rt_def.h"
#include "_z_zone.h"
#include "z_zone.h"
#include "rt_util.h"
#include "develop.h"
#include "rt_net.h"

#if (DEVELOPMENT == 1)
#include "rt_main.h"
#endif
//MED
#include "memcheck.h"

int lowmemory=0;

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

                                                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

It is of no value to free a cachable block, because it will get overwritten
automatically if needed

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

//Globals

int zonememorystarted=0;

// Statics

static memzone_t       *mainzone;
static memzone_t       *levelzone;
static int levelzonesize=LEVELZONESIZE;
static struct meminfo
   {
   unsigned LargestBlockAvail;
   unsigned MaxUnlockedPage;
   unsigned LargestLockablePage;
   unsigned LinAddrSpace;
   unsigned NumFreePagesAvail;
   unsigned NumPhysicalPagesFree;
   unsigned TotalPhysicalPages;
   unsigned FreeLinAddrSpace;
   unsigned SizeOfPageFile;
   unsigned Reserved[3];
   } MemInfo;

/*
========================
=
= Z_ClearZone
=
========================
*/

void Z_ClearZone (memzone_t *zone)
{
        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.user = (void *)zone;
        zone->blocklist.tag = PU_STATIC;
        zone->rover = block;

        block->prev = block->next = &zone->blocklist;
        block->user = NULL;     // free block
        block->size = zone->size - sizeof(memzone_t);
}


/*
========================
=
= Z_AllocateZone
=
========================
*/

memzone_t *Z_AllocateZone (int size)
{
        memzone_t       *header;

        header = malloc (size+sizeof(memzone_t));
        if (!header)
                Error ("Z_AllocateZone: Couldn't malloc %zd bytes avail=%d\n",
                size+sizeof(memzone_t), Z_AvailHeap());
        header->size = size;
        Z_ClearZone (header);
        return header;
}

/*
========================
=
= Z_Init
=
========================
*/
void Z_Init (int size, int min)
{
   int maxsize;
   int sz;

   if (zonememorystarted==1)
      return;
   zonememorystarted=1;

   sz = GamePacketSize();

   sz*=MAXCMDS;

   if (ConsoleIsServer() == true)
      levelzonesize+=((numplayers*2)+1)*sz;
   else
      levelzonesize+=(numplayers+1)*sz;

   maxsize=((int)(Z_AvailHeap())-size-levelzonesize);
   if (maxsize<min)
      {
      UL_DisplayMemoryError (min-maxsize);
      }
   if (maxsize>MAXMEMORYSIZE)
      maxsize=(MAXMEMORYSIZE-levelzonesize);

   mainzone = Z_AllocateZone (maxsize);
   levelzone = Z_AllocateZone (levelzonesize);

   if (!quiet)
      printf("Z_INIT: %ld bytes\n",(long int)(maxsize+levelzonesize));

   if (maxsize<(min+(min>>1)))
      {
      lowmemory = 1;

      printf("==============================================================================\n");
      printf("WARNING: You are running ROTT with very little memory.  ROTT runs best with\n");
      printf("8 Megabytes of memory and no TSR's loaded in memory.  If you can free up more\n");
      printf("memory for ROTT then you should press CTRL-BREAK at this time. If you are\n");
      printf("unable to do this you will experience momentary pauses in game-play whenever\n");
      printf("you enter new areas of the game as well as an overall decreased performance.\n");
      printf("                        Press any key to continue\n");
      printf("==============================================================================\n");
      getch();
      }
}

/*
========================
=
= Z_ShutDown
=
========================
*/

void Z_ShutDown( void )
{
   if (zonememorystarted==0)
      return;
   zonememorystarted=0;
   free(mainzone);
   free(levelzone);
}

/*
========================
=
= Z_GetSize
=
========================
*/

int Z_GetSize (void *ptr)
{
        memblock_t      *block;

        block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
        return (block->size - sizeof(memblock_t));
}


/*
========================
=
= Z_Free
=
========================
*/

void Z_Free (void *ptr)
{
        memblock_t      *block, *other;

        block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
        if (!block->user)
                Error ("Z_Free: freed a freed pointer");

        if (block->user > (void **)0x100)       // smaller values are not pointers
                *block->user = 0;               // clear the user's mark
        block->user = NULL;     // mark as free

        other = block->prev;
        if (!other->user)
        {       // merge with previous free block
                other->size += block->size;
                other->next = block->next;
                other->next->prev = other;
                if (block == mainzone->rover)
                        mainzone->rover = other;
                else if (block == levelzone->rover)
                        levelzone->rover = other;
                block = other;
        }

        other = block->next;
        if (!other->user)
        {       // 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;
                else if (other == levelzone->rover)
                        levelzone->rover = block;
        }
}


/*
========================
=
= Z_Malloc
=
= You can pass a NULL user if the tag is < PU_PURGELEVEL
========================
*/

#if (DEVELOPMENT == 1)
int totallevelsize=0;
#endif

void *Z_Malloc (int size, int tag, void *user)
{
        int             extra;
        memblock_t      *start, *rover, *new, *base;

//
// scan through the block list looking for the first free block
// of sufficient size, throwing out any purgable blocks along the way
//
//        size += sizeof(memblock_t);     // account for size of block header
        size = (size + sizeof(memblock_t) + 3)&~3;     // account for size of block header


//
// if there is a free block behind the rover, back up over them
//
        base = mainzone->rover;
        if (!base->prev->user)
                base = base->prev;

        rover = base;
        start = base->prev;

        do
        {
                if (rover == start)     // scaned all the way around the list
                        {
                        SoftError("OHSHIT\n");
                        Z_DumpHeap(0,200);
                        Error ("Z_Malloc: failed on allocation of %i bytes",size);
                        }
                if (rover->user)
                {
                        if (rover->tag < PU_PURGELEVEL)
                        // hit a block that can't be purged, so move base past it
                                base = rover = rover->next;
                        else
                        {
                        // free the rover block (adding the size to base)
                                base = base->prev;      // the rover can be the base block
                                Z_Free ((byte *)rover+sizeof(memblock_t));
                                base = base->next;
                                rover = base->next;
                        }
                }
                else
                        rover = rover->next;
        } while (base->user || 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->user = NULL;               // free block
                new->tag = 0;
                new->prev = base;
                new->next = base->next;
                new->next->prev = new;
                base->next = new;
                base->size = size;
        }

        if (user)
        {
                base->user = user;                      // mark as an in use block
                *(void **)user = (void *) ((byte *)base + sizeof(memblock_t));
        }
        else
        {
                if (tag >= PU_PURGELEVEL)
                        Error ("Z_Malloc: an owner is required for purgable blocks");
                base->user = (void *)2;         // mark as in use, but unowned
        }
        base->tag = tag;

        mainzone->rover = base->next;   // next allocation will start looking here


#if (MEMORYCORRUPTIONTEST==1)
         base->posttag=MEMORYPOSTTAG;
         base->pretag=MEMORYPRETAG;
#endif

        return (void *) ((byte *)base + sizeof(memblock_t));
}

/*
========================
=
= Z_LevelMalloc
=
= Only use this for level structures.
= You can pass a NULL user if the tag is < PU_PURGELEVEL
========================
*/

void *Z_LevelMalloc (int size, int tag, void *user)
{
        int             extra;
        memblock_t      *start, *rover, *new, *base;

//
// scan through the block list looking for the first free block
// of sufficient size, throwing out any purgable blocks along the way
//
//        size += sizeof(memblock_t);     // account for size of block header
        size = (size + sizeof(memblock_t) + 3)&~3;     // account for size of block header


//
// if there is a free block behind the rover, back up over them
//
        base = levelzone->rover;
        if (!base->prev->user)
                base = base->prev;

        rover = base;
        start = base->prev;

        do
        {
                if (rover == start)     // scaned all the way around the list
                        {
                        SoftError("OHSHIT\n");
                        Z_DumpHeap(0,200);
                        Error ("Z_LevelMalloc: failed on allocation of %i bytes",size);
                        }
                if (rover->user)
                {
                        if (rover->tag < PU_PURGELEVEL)
                        // hit a block that can't be purged, so move base past it
                                base = rover = rover->next;
                        else
                        {
                        // free the rover block (adding the size to base)
                                base = base->prev;      // the rover can be the base block
                                Z_Free ((byte *)rover+sizeof(memblock_t));
                                base = base->next;
                                rover = base->next;
                        }
                }
                else
                        rover = rover->next;
        } while (base->user || 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->user = NULL;               // free block
                new->tag = 0;
                new->prev = base;
                new->next = base->next;
                new->next->prev = new;
                base->next = new;
                base->size = size;
        }

        if (user)
        {
                base->user = user;                      // mark as an in use block
                *(void **)user = (void *) ((byte *)base + sizeof(memblock_t));
        }
        else
        {
                if (tag >= PU_PURGELEVEL)
                        Error ("Z_Malloc: an owner is required for purgable blocks");
                base->user = (void *)2;         // mark as in use, but unowned
        }
        base->tag = tag;

        levelzone->rover = base->next;   // next allocation will start looking here

#if (MEMORYCORRUPTIONTEST==1)
         base->posttag=MEMORYPOSTTAG;
         base->pretag=MEMORYPRETAG;
#endif

        return (void *) ((byte *)base + sizeof(memblock_t));
}



/*
========================
=
= Z_FreeTags
=
========================
*/

void Z_FreeTags (int lowtag, int hightag)
{
        memblock_t      *block, *next;

        for (block = mainzone->blocklist.next ; block != &mainzone->blocklist
        ; block = next)
        {
                next = block->next;             // get link before freeing
                if (!block->user)
                        continue;                       // free block
                if (block->tag >= lowtag && block->tag <= hightag)
                        Z_Free ( (byte *)block+sizeof(memblock_t));
        }
        for (block = levelzone->blocklist.next ; block != &levelzone->blocklist
        ; block = next)
        {
                next = block->next;             // get link before freeing
                if (!block->user)
                        continue;                       // free block
                if (block->tag >= lowtag && block->tag <= hightag)
                        Z_Free ( (byte *)block+sizeof(memblock_t));
        }
}

/*
========================
=
= Z_DumpHeap
=
========================
*/

void Z_DumpHeap (int lowtag, int hightag)
{
        memblock_t      *block;
        int             totalsize;

        SoftError("MAIN ZONE\n");
        SoftError("zone size: %i  location: %p\n",mainzone->size,mainzone);
        SoftError("tag range: %i to %i\n",lowtag, hightag);

        totalsize=0;

        for (block = mainzone->blocklist.next ; ; block = block->next)
        {
                if (block->tag >= lowtag && block->tag <= hightag)
                        {
                        SoftError("block:%p    size:%7i    user:%p    tag:%3i\n",
                        block, block->size, block->user, block->tag);
                        totalsize+=block->size;
                        }

                if (block->next == &mainzone->blocklist) {
                        break;                  // all blocks have been hit
		}
                if ( (byte *)block + block->size != (byte *)block->next) {
                        SoftError("ERROR: block size does not touch the next block\n");
		}
                if ( block->next->prev != block) {
                        SoftError("ERROR: next block doesn't have proper back link\n");
		}
                if (!block->user && !block->next->user) {
                        SoftError("ERROR: two consecutive free blocks\n");
		}
        }
        SoftError("Total Size of blocks = %d\n",totalsize);

        SoftError("LEVEL ZONE\n");
        SoftError("zone size: %i  location: %p\n",levelzone->size,levelzone);
        SoftError("tag range: %i to %i\n",lowtag, hightag);

        totalsize=0;

        for (block = levelzone->blocklist.next ; ; block = block->next)
        {
                if (block->tag >= lowtag && block->tag <= hightag)
                        {
                        SoftError("block:%p    size:%7i    user:%p    tag:%3i\n",
                        block, block->size, block->user, block->tag);
                        totalsize+=block->size;
                        }

                if (block->next == &levelzone->blocklist)
                        break;                  // all blocks have been hit
                if ( (byte *)block + block->size != (byte *)block->next) {
                        SoftError("ERROR: block size does not touch the next block\n");
		}
                if ( block->next->prev != block) {
                        SoftError("ERROR: next block doesn't have proper back link\n");
		}
                if (!block->user && !block->next->user) {
                        SoftError("ERROR: two consecutive free blocks\n");
		}
        }
        SoftError("Total Size of blocks = %d\n",totalsize);

}

/*
========================
=
= Z_UsedHeap
=
========================
*/

int Z_UsedHeap ( void )
{
        memblock_t      *block;
        int heapsize;


        heapsize=0;
        for (block = mainzone->blocklist.next ; ; block = block->next)
        {
                if ((block->tag>0) && (block->user>(void **)0))
                   heapsize+=(block->size);
                if (block->next == &mainzone->blocklist)
                   break;                  // all blocks have been hit
        }
        return heapsize;
}

/*
========================
=
= Z_UsedLevelHeap
=
========================
*/

int Z_UsedLevelHeap ( void )
{
        memblock_t      *block;
        int heapsize;


        heapsize=0;
        for (block = levelzone->blocklist.next ; ; block = block->next)
        {
                if ((block->tag>0) && (block->user>(void **)0))
                   heapsize+=(block->size);
                if (block->next == &levelzone->blocklist)
                   break;                  // all blocks have been hit
        }
        return heapsize;
}


/*
========================
=
= Z_UsedStaticHeap
=
========================
*/

int Z_UsedStaticHeap ( void )
{
        memblock_t      *block;
        int heapsize;


        heapsize=0;
        for (block = mainzone->blocklist.next ; ; block = block->next)
        {
                if ((block->tag>0) && (block->tag<PU_PURGELEVEL) && (block->user>(void **)0))
                   heapsize+=(block->size);
                if (block->next == &mainzone->blocklist)
                   break;                  // all blocks have been hit
        }
        return heapsize;
}


/*
========================
=
= Z_HeapSize
=
========================
*/

int Z_HeapSize ( void )
{
   return mainzone->size;
}


/*
========================
=
= Z_CheckHeap
=
========================
*/

void Z_CheckHeap (void)
{
        memblock_t      *block;

        // Check mainzone

        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)
                        Error ("Z_CheckHeap: block size does not touch the next block\n");
                if ( block->next->prev != block)
                        Error ("Z_CheckHeap: next block doesn't have proper back link\n");
                if (!block->user && !block->next->user)
                        Error ("Z_CheckHeap: two consecutive free blocks\n");
#if (MEMORYCORRUPTIONTEST==1)
                if ((block->tag>0) && (block->user>0))
                   {
                   if (block->posttag!=MEMORYPOSTTAG)
                      Error("Z_CheckHeap: Corrupted posttag\n");
                   if (block->pretag!=MEMORYPRETAG)
                      Error("Z_CheckHeap: Corrupted pretag\n");
                   }
#endif
        }

        // Check levelzone

        for (block = levelzone->blocklist.next ; ; block = block->next)
        {
                if (block->next == &levelzone->blocklist)
                        break;                  // all blocks have been hit
                if ( (byte *)block + block->size != (byte *)block->next)
                        Error ("Z_CheckHeap: block size does not touch the next block\n");
                if ( block->next->prev != block)
                        Error ("Z_CheckHeap: next block doesn't have proper back link\n");
                if (!block->user && !block->next->user)
                        Error ("Z_CheckHeap: two consecutive free blocks\n");
#if (MEMORYCORRUPTIONTEST==1)
                if ((block->tag>0) && (block->user>0))
                   {
                   if (block->posttag!=MEMORYPOSTTAG)
                      Error("Z_CheckHeap: Corrupted posttag\n");
                   if (block->pretag!=MEMORYPRETAG)
                      Error("Z_CheckHeap: Corrupted pretag\n");
                   }
#endif
        }
}


/*
========================
=
= Z_ChangeTag
=
========================
*/

void Z_ChangeTag (void *ptr, int tag)
{
        memblock_t      *block;

        block = (memblock_t *) ( (byte *)ptr - sizeof(memblock_t));
        block->tag = tag;
}

/*
========================
=
= Z_AvailHeap
=
========================
*/

int Z_AvailHeap ( void )
{
#ifdef DOS
   union REGS zregs;
   struct SREGS zsregs;


   zregs.x.eax = 0x00000500;
   memset( &zsregs, 0, sizeof(zsregs) );
   zsregs.es = FP_SEG( &MemInfo );
   zregs.x.edi = FP_OFF( &MemInfo );

   int386x( DPMI_INT, &zregs, &zregs, &zsregs );

   return ((int)MemInfo.LargestBlockAvail);
#else
	return MAXMEMORYSIZE;
#endif
}

/*
========================
=
= Z_Realloc
=
========================
*/

void Z_Realloc (void ** ptr, int newsize)
{
   memblock_t      *block;
   void * newptr;
   int oldsize;

   block = (memblock_t *) ( (byte *)(*ptr) - sizeof(memblock_t));
   oldsize = block->size;
   newptr = SafeMalloc(newsize);
   if (oldsize > newsize)
      {
      oldsize = newsize;
      }
   memcpy( newptr, *ptr, oldsize );
   SafeFree( *ptr );
   *ptr = newptr;
}