// Emacs style mode select   -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id: z_zone.c,v 1.13 1998/05/12 06:11:55 killough Exp $
//
//  BOOM, a modified and improved DOOM engine
//  Copyright (C) 1999 by
//  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
//
//  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.
//
// DESCRIPTION:
//      Zone Memory Allocation. Neat.
//
// Neat enough to be rewritten by Lee Killough...
//
// Must not have been real neat :)
//
// Made faster and more general, and added wrappers for all of Doom's
// memory allocation functions, including malloc() and similar functions.
// Added line and file numbers, in case of error. Added performance
// statistics and tunables.
//-----------------------------------------------------------------------------

static const char rcsid[] = "$Id: z_zone.c,v 1.13 1998/05/12 06:11:55 killough Exp $";

#include "z_zone.h"
#include "doomstat.h"

#ifdef DJGPP
#include <dpmi.h>
#endif

// Uncomment this to see real-time memory allocation
// statistics, to and enable extra debugging features
//#define INSTRUMENTED

// Uncomment this to exhaustively run memory checks
// while the game is running (this is EXTREMELY slow).
// Only useful if INSTRUMENTED is also defined.
//#define CHECKHEAP

// Uncomment this to perform id checks on zone blocks,
// to detect corrupted and illegally freed blocks
#define ZONEIDCHECK

// Tunables

// Alignment of zone memory (benefit may be negated by HEADER_SIZE, CHUNK_SIZE)
#define CACHE_ALIGN 32

// size of block header
#define HEADER_SIZE 32

// Minimum chunk size at which blocks are allocated
#define CHUNK_SIZE 32

// Minimum size a block must be to become part of a split
#define MIN_BLOCK_SPLIT (1024)

// How much RAM to leave aside for other libraries
#define LEAVE_ASIDE (128*1024)

// Minimum RAM machine is assumed to have
#define MIN_RAM (7*1024*1024)

// Amount to subtract when retrying failed attempts to allocate initial pool
#define RETRY_AMOUNT (256*1024)

// signature for block header
#define ZONEID  0x931d4a11

// Number of mallocs & frees kept in history buffer (must be a power of 2)
#define ZONE_HISTORY 4

// End Tunables

typedef struct memblock {

#ifdef ZONEIDCHECK
  unsigned id;
#endif

  struct memblock *next,*prev;
  size_t size;
  void **user;
  unsigned char tag,vm;

#ifdef INSTRUMENTED
  unsigned short extra;
  const char *file;
  int line;
#endif

} memblock_t;

static memblock_t *rover;                // roving pointer to memory blocks
static memblock_t *zone;                 // pointer to first block
static memblock_t *zonebase;             // pointer to entire zone memory
static size_t zonebase_size;             // zone memory allocated size
static memblock_t *blockbytag[PU_MAX];

#ifdef INSTRUMENTED

// statistics for evaluating performance
static size_t free_memory;
static size_t active_memory;
static size_t purgable_memory;
static size_t inactive_memory;
static size_t virtual_memory;

static void Z_PrintStats(void)            // Print allocation statistics
{
  unsigned long total_memory = free_memory + active_memory +
                               purgable_memory + inactive_memory +
                               virtual_memory;
  double s = 100.0 / total_memory;

  dprintf("%-5lu\t%6.01f%%\tstatic\n"
          "%-5lu\t%6.01f%%\tpurgable\n"
          "%-5lu\t%6.01f%%\tfree\n"
          "%-5lu\t%6.01f%%\tfragmentary\n"
          "%-5lu\t%6.01f%%\tvirtual\n"
          "%-5lu\t\ttotal\n",
          active_memory,
          active_memory*s,
          purgable_memory,
          purgable_memory*s,
          free_memory,
          free_memory*s,
          inactive_memory,
          inactive_memory*s,
          virtual_memory,
          virtual_memory*s,
          total_memory
          );
}
#endif

#ifdef INSTRUMENTED

// killough 4/26/98: Add history information

enum {malloc_history, free_history, NUM_HISTORY_TYPES};

static const char *file_history[NUM_HISTORY_TYPES][ZONE_HISTORY];
static int line_history[NUM_HISTORY_TYPES][ZONE_HISTORY];
static int history_index[NUM_HISTORY_TYPES];
static const char *const desc[NUM_HISTORY_TYPES] = {"malloc()'s", "free()'s"};

void Z_DumpHistory(char *buf)
{
  int i,j;
  char s[1024];
  strcat(buf,"\n");
  for (i=0;i<NUM_HISTORY_TYPES;i++)
    {
      sprintf(s,"\nLast several %s:\n\n", desc[i]);
      strcat(buf,s);
      for (j=0; j<ZONE_HISTORY; j++)
        {
          int k = (history_index[i]-j-1) & (ZONE_HISTORY-1);
          if (file_history[i][k])
            {
              sprintf(s, "File: %s, Line: %d\n", file_history[i][k],
                      line_history[i][k]);
              strcat(buf,s);
            }
        }
    }
}
#else

void Z_DumpHistory(char *buf)
{
}

#endif

static void Z_Close(void)
{
  (free)(zonebase);
  zone = rover = zonebase = NULL;
}

void Z_Init(void)
{
#ifdef DJGPP
  size_t size = _go32_dpmi_remaining_physical_memory();    // Get free RAM
#else
  size_t size = MIN_RAM;
#endif

  if (size < MIN_RAM)         // If less than MIN_RAM, assume MIN_RAM anyway
    size = MIN_RAM;

  size -= LEAVE_ASIDE;        // Leave aside some for other libraries

  assert(HEADER_SIZE >= sizeof(memblock_t) && MIN_RAM > LEAVE_ASIDE);

  atexit(Z_Close);            // exit handler

  size = (size+CHUNK_SIZE-1) & ~(CHUNK_SIZE-1);  // round to chunk size

   // Allocate the memory

  while (!(zonebase=(malloc)(zonebase_size=size + HEADER_SIZE + CACHE_ALIGN)))
    if (size < (MIN_RAM-LEAVE_ASIDE < RETRY_AMOUNT ? RETRY_AMOUNT :
                                                     MIN_RAM-LEAVE_ASIDE))
      I_Error("Z_Init: failed on allocation of %lu bytes",(unsigned long)
              zonebase_size);
    else
      size -= RETRY_AMOUNT;

  // Align on cache boundary

  zone = (memblock_t *) ((char *) zonebase + CACHE_ALIGN -
                         ((unsigned) zonebase & (CACHE_ALIGN-1)));

  rover = zone;                            // Rover points to base of zone mem
  zone->next = zone->prev = zone;          // Single node
  zone->size = size;                       // All memory in one block
  zone->tag = PU_FREE;                     // A free block
  zone->vm  = 0;

#ifdef ZONEIDCHECK
  zone->id  = 0;
#endif

#ifdef INSTRUMENTED
  free_memory = size;
  inactive_memory = zonebase_size - size;
  active_memory = purgable_memory = 0;
#endif
}

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

void *(Z_Malloc)(size_t size, int tag, void **user, const char *file, int line)
{
  register memblock_t *block;
  memblock_t *start;

#ifdef INSTRUMENTED
  size_t size_orig = size;
#ifdef CHECKHEAP
  Z_CheckHeap();
#endif

  file_history[malloc_history][history_index[malloc_history]] = file;
  line_history[malloc_history][history_index[malloc_history]++] = line;
  history_index[malloc_history] &= ZONE_HISTORY-1;
#endif

#ifdef ZONEIDCHECK
  if (tag >= PU_PURGELEVEL && !user)
    I_Error ("Z_Malloc: an owner is required for purgable blocks\n"
             "Source: %s:%d", file, line);
#endif

  if (!size)
    return user ? *user = NULL : NULL;           // malloc(0) returns NULL

  size = (size+CHUNK_SIZE-1) & ~(CHUNK_SIZE-1);  // round to chunk size

  block = rover;

  if (block->prev->tag == PU_FREE)
    block = block->prev;

  start = block;

  do
    {
      if (block->tag >= PU_PURGELEVEL)      // Free purgable blocks
        {                                   // replacement is roughly FIFO
          start = block->prev;
          Z_Free((char *) block + HEADER_SIZE);
          block = start = start->next;      // Important: resets start
        }

      if (block->tag == PU_FREE && block->size >= size)   // First-fit
        {
          size_t extra = block->size - size;
          if (extra >= MIN_BLOCK_SPLIT + HEADER_SIZE)
            {
              memblock_t *newb = (memblock_t *)((char *) block +
                                                HEADER_SIZE + size);

              (newb->next = block->next)->prev = newb;
              (newb->prev = block)->next = newb;          // Split up block
              block->size = size;
              newb->size = extra - HEADER_SIZE;
              newb->tag = PU_FREE;
              newb->vm = 0;

#ifdef INSTRUMENTED
              inactive_memory += HEADER_SIZE;
              free_memory -= HEADER_SIZE;
#endif
            }

          rover = block->next;           // set roving pointer for next search

#ifdef INSTRUMENTED
          inactive_memory += block->extra = block->size - size_orig;
          if (tag >= PU_PURGELEVEL)
            purgable_memory += size_orig;
          else
            active_memory += size_orig;
          free_memory -= block->size;
#endif

allocated:

#ifdef INSTRUMENTED
          block->file = file;
          block->line = line;
#endif

#ifdef ZONEIDCHECK
          block->id = ZONEID;         // signature required in block header
#endif
          block->tag = tag;           // tag
          block->user = user;         // user
          block = (memblock_t *)((char *) block + HEADER_SIZE);
          if (user)                   // if there is a user
            *user = block;            // set user to point to new block

#ifdef INSTRUMENTED
          Z_PrintStats();           // print memory allocation stats
          // scramble memory -- weed out any bugs
          memset(block, gametic & 0xff, size);
#endif
          return block;
        }
    }
  while ((block = block->next) != start);   // detect cycles as failure

  // We've run out of physical memory, or so we think.
  // Although less efficient, we'll just use ordinary malloc.
  // This will squeeze the remaining juice out of this machine
  // and start cutting into virtual memory if it has it.

  while (!(block = (malloc)(size + HEADER_SIZE)))
    {
      if (!blockbytag[PU_CACHE])
        I_Error ("Z_Malloc: Failure trying to allocate %lu bytes"
                 "\nSource: %s:%d",(unsigned long) size, file, line);
      Z_FreeTags(PU_CACHE,PU_CACHE);
    }

  if ((block->next = blockbytag[tag]))
    block->next->prev = (memblock_t *) &block->next;
  blockbytag[tag] = block;
  block->prev = (memblock_t *) &blockbytag[tag];
  block->vm = 1;

#ifdef INSTRUMENTED
  virtual_memory += block->size = size + HEADER_SIZE;
#endif

  goto allocated;
}

void (Z_Free)(void *p, const char *file, int line)
{
#ifdef INSTRUMENTED
#ifdef CHECKHEAP
  Z_CheckHeap();
#endif
  file_history[free_history][history_index[free_history]] = file;
  line_history[free_history][history_index[free_history]++] = line;
  history_index[free_history] &= ZONE_HISTORY-1;
#endif

  if (p)
    {
      memblock_t *other, *block = (memblock_t *)((char *) p - HEADER_SIZE);

#ifdef ZONEIDCHECK
      if (block->id != ZONEID)
        I_Error("Z_Free: freed a pointer without ZONEID\n"
                "Source: %s:%d"

#ifdef INSTRUMENTED
                "\nSource of malloc: %s:%d"
                , file, line, block->file, block->line
#else
                , file, line
#endif
                );
      block->id = 0;              // Nullify id so another free fails
#endif

#ifdef INSTRUMENTED
      // scramble memory -- weed out any bugs
      memset(p, gametic & 0xff, block->size - block->extra);
#endif

      if (block->user)            // Nullify user if one exists
        *block->user = NULL;

      if (block->vm)
        {
          if ((*(memblock_t **) block->prev = block->next))
            block->next->prev = block->prev;

#ifdef INSTRUMENTED
          virtual_memory -= block->size;
#endif
          (free)(block);
        }
      else
        {

#ifdef INSTRUMENTED
          free_memory += block->size;
          inactive_memory -= block->extra;
          if (block->tag >= PU_PURGELEVEL)
            purgable_memory -= block->size - block->extra;
          else
            active_memory -= block->size - block->extra;
#endif

          block->tag = PU_FREE;       // Mark block freed

          if (block != zone)
            {
              other = block->prev;        // Possibly merge with previous block
              if (other->tag == PU_FREE)
                {
                  if (rover == block)  // Move back rover if it points at block
                    rover = other;
                  (other->next = block->next)->prev = other;
                  other->size += block->size + HEADER_SIZE;
                  block = other;

#ifdef INSTRUMENTED
                  inactive_memory -= HEADER_SIZE;
                  free_memory += HEADER_SIZE;
#endif
                }
            }

          other = block->next;        // Possibly merge with next block
          if (other->tag == PU_FREE && other != zone)
            {
              if (rover == other) // Move back rover if it points at next block
                rover = block;
              (block->next = other->next)->prev = block;
              block->size += other->size + HEADER_SIZE;

#ifdef INSTRUMENTED
              inactive_memory -= HEADER_SIZE;
              free_memory += HEADER_SIZE;
#endif
            }
        }

#ifdef INSTRUMENTED
      Z_PrintStats();           // print memory allocation stats
#endif
    }
}

void (Z_FreeTags)(int lowtag, int hightag, const char *file, int line)
{
  memblock_t *block = zone;

  if (lowtag <= PU_FREE)
    lowtag = PU_FREE+1;

  do               // Scan through list, searching for tags in range
    if (block->tag >= lowtag && block->tag <= hightag)
      {
        memblock_t *prev = block->prev;
        (Z_Free)((char *) block + HEADER_SIZE, file, line);
        block = prev->next;
      }
  while ((block=block->next) != zone);

  if (hightag > PU_CACHE)
    hightag = PU_CACHE;

  for (;lowtag <= hightag; lowtag++)
    for (block = blockbytag[lowtag], blockbytag[lowtag] = NULL; block;)
      {
        memblock_t *next = block->next;

#ifdef ZONEIDCHECK
        if (block->id != ZONEID)
          I_Error("Z_Free: freed a pointer without ZONEID\n"
                  "Source: %s:%d"

#ifdef INSTRUMENTED
                  "\nSource of malloc: %s:%d"
                  , file, line, block->file, block->line
#else
                  , file, line
#endif
                  );

        block->id = 0;              // Nullify id so another free fails
#endif

#ifdef INSTRUMENTED
        virtual_memory -= block->size;
#endif

        if (block->user)            // Nullify user if one exists
          *block->user = NULL;

        (free)(block);              // Free the block

        block = next;               // Advance to next block
      }
}

void (Z_ChangeTag)(void *ptr, int tag, const char *file, int line)
{
  memblock_t *block = (memblock_t *)((char *) ptr - HEADER_SIZE);

#ifdef INSTRUMENTED
#ifdef CHECKHEAP
  Z_CheckHeap();
#endif
#endif

#ifdef ZONEIDCHECK
  if (block->id != ZONEID)
    I_Error ("Z_ChangeTag: freed a pointer without ZONEID"
             "\nSource: %s:%d"

#ifdef INSTRUMENTED
             "\nSource of malloc: %s:%d"
             , file, line, block->file, block->line
#else
             , file, line
#endif
             );

  if (tag >= PU_PURGELEVEL && !block->user)
    I_Error ("Z_ChangeTag: an owner is required for purgable blocks\n"
             "Source: %s:%d"
#ifdef INSTRUMENTED
             "\nSource of malloc: %s:%d"
             , file, line, block->file, block->line
#else
             , file, line
#endif
             );

#endif // ZONEIDCHECK

  if (block->vm)
    {
      if ((*(memblock_t **) block->prev = block->next))
        block->next->prev = block->prev;
      if ((block->next = blockbytag[tag]))
        block->next->prev = (memblock_t *) &block->next;
      block->prev = (memblock_t *) &blockbytag[tag];
      blockbytag[tag] = block;
    }
  else
    {
#ifdef INSTRUMENTED
      if (block->tag < PU_PURGELEVEL && tag >= PU_PURGELEVEL)
        {
          active_memory -= block->size - block->extra;
          purgable_memory += block->size - block->extra;
        }
      else
        if (block->tag >= PU_PURGELEVEL && tag < PU_PURGELEVEL)
          {
            active_memory += block->size - block->extra;
            purgable_memory -= block->size - block->extra;
          }
#endif
    }
  block->tag = tag;
}

void *(Z_Realloc)(void *ptr, size_t n, int tag, void **user,
                  const char *file, int line)
{
  void *p = (Z_Malloc)(n, tag, user, file, line);
  if (ptr)
    {
      memblock_t *block = (memblock_t *)((char *) ptr - HEADER_SIZE);
      memcpy(p, ptr, n <= block->size ? n : block->size);
      (Z_Free)(ptr, file, line);
      if (user) // in case Z_Free nullified same user
        *user=p;
    }
  return p;
}

void *(Z_Calloc)(size_t n1, size_t n2, int tag, void **user,
                 const char *file, int line)
{
  return
    (n1*=n2) ? memset((Z_Malloc)(n1, tag, user, file, line), 0, n1) : NULL;
}

char *(Z_Strdup)(const char *s, int tag, void **user,
                 const char *file, int line)
{
  return strcpy((Z_Malloc)(strlen(s)+1, tag, user, file, line), s);
}

void (Z_CheckHeap)(const char *file, int line)
{
  memblock_t *block = zone;   // Start at base of zone mem
  do                          // Consistency check (last node treated special)
    if ((block->next != zone &&
         (memblock_t *)((char *) block+HEADER_SIZE+block->size) != block->next)
        || block->next->prev != block || block->prev->next != block)
      I_Error("Z_CheckHeap: Block size does not touch the next block\n"
              "Source: %s:%d"
#ifdef INSTRUMENTED
              "\nSource of offending block: %s:%d"
              , file, line, block->file, block->line
#else
              , file, line
#endif
              );
  while ((block=block->next) != zone);
}

//-----------------------------------------------------------------------------
//
// $Log: z_zone.c,v $
// Revision 1.13  1998/05/12  06:11:55  killough
// Improve memory-related error messages
//
// Revision 1.12  1998/05/03  22:37:45  killough
// beautification
//
// Revision 1.11  1998/04/27  01:49:39  killough
// Add history of malloc/free and scrambler (INSTRUMENTED only)
//
// Revision 1.10  1998/03/28  18:10:33  killough
// Add memory scrambler for debugging
//
// Revision 1.9  1998/03/23  03:43:56  killough
// Make Z_CheckHeap() more diagnostic
//
// Revision 1.8  1998/03/02  11:40:02  killough
// Put #ifdef CHECKHEAP around slow heap checks (debug)
//
// Revision 1.7  1998/02/02  13:27:45  killough
// Additional debug info turned on with #defines
//
// Revision 1.6  1998/01/26  19:25:15  phares
// First rev with no ^Ms
//
// Revision 1.5  1998/01/26  07:15:43  phares
// Added rcsid
//
// Revision 1.4  1998/01/26  06:12:30  killough
// Fix memory usage problems and improve debug stat display
//
// Revision 1.3  1998/01/22  05:57:20  killough
// Allow use of virtual memory when physical memory runs out
//
// ???
//
//-----------------------------------------------------------------------------
