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malloc.h

/* Declarations for `malloc' and friends.
   Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
              Written May 1989 by Mike Haertel.

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

This library 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.

   The author may be reached (Email) at the address mike@ai.mit.edu,
   or (US mail) as Mike Haertel c/o Free Software Foundation.  */

#ifndef _MALLOC_H

#define _MALLOC_H 1

#ifdef      __cplusplus
extern "C"
{
#endif

#if defined (__cplusplus) || (defined (__STDC__) && __STDC__)
#undef      __P
#define     __P(args)   args
#undef      __ptr_t
#define     __ptr_t           void *
#else /* Not C++ or ANSI C.  */
#undef      __P
#define     __P(args)   ()
#undef      const
#define     const
#undef      __ptr_t
#define     __ptr_t           char *
#endif /* C++ or ANSI C.  */

#ifndef     NULL
#define     NULL  0
#endif

#ifdef      __STDC__
#include <stddef.h>
#else
#undef      size_t
#define     size_t            unsigned int
#undef      ptrdiff_t
#define     ptrdiff_t   int
#endif


/* Allocate SIZE bytes of memory.  */
extern __ptr_t malloc __P ((size_t __size));
/* Re-allocate the previously allocated block
   in __ptr_t, making the new block SIZE bytes long.  */
extern __ptr_t realloc __P ((__ptr_t __ptr, size_t __size));
/* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
extern __ptr_t calloc __P ((size_t __nmemb, size_t __size));
/* Free a block allocated by `malloc', `realloc' or `calloc'.  */
extern void free __P ((__ptr_t __ptr));

/* Allocate SIZE bytes allocated to ALIGNMENT bytes.  */
extern __ptr_t memalign __P ((size_t __alignment, size_t __size));

/* Allocate SIZE bytes on a page boundary.  */
extern __ptr_t valloc __P ((size_t __size));


#ifdef _MALLOC_INTERNAL

#include <stdio.h>            /* Harmless, gets __GNU_LIBRARY__ defined.  */

#if   defined(__GNU_LIBRARY__) || defined(STDC_HEADERS) || defined(USG)
#include <string.h>
#else
#ifndef memset
#define     memset(s, zero, n)      bzero ((s), (n))
#endif
#ifndef memcpy
#define     memcpy(d, s, n)         bcopy ((s), (d), (n))
#endif
#endif


#if   defined(__GNU_LIBRARY__) || defined(__STDC__)
#include <limits.h>
#else
#define     CHAR_BIT    8
#endif

/* The allocator divides the heap into blocks of fixed size; large
   requests receive one or more whole blocks, and small requests
   receive a fragment of a block.  Fragment sizes are powers of two,
   and all fragments of a block are the same size.  When all the
   fragments in a block have been freed, the block itself is freed.  */
#define INT_BIT         (CHAR_BIT * sizeof(int))
#define BLOCKLOG  (INT_BIT > 16 ? 12 : 9)
#define BLOCKSIZE (1 << BLOCKLOG)
#define BLOCKIFY(SIZE)  (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE)

/* Determine the amount of memory spanned by the initial heap table
   (not an absolute limit).  */
#define HEAP            (INT_BIT > 16 ? 4194304 : 65536)

/* Number of contiguous free blocks allowed to build up at the end of
   memory before they will be returned to the system.  */
#define FINAL_FREE_BLOCKS     8

/* Data structure giving per-block information.  */
typedef union
  {
    /* Heap information for a busy block.  */
    struct
      {
      /* Zero for a large block, or positive giving the
         logarithm to the base two of the fragment size.  */
      int type;
      union
        {
          struct
            {
            size_t nfree;     /* Free fragments in a fragmented block.  */
            size_t first;     /* First free fragment of the block.  */
            } frag;
          /* Size (in blocks) of a large cluster.  */
          size_t size;
        } info;
      } busy;
    /* Heap information for a free block
       (that may be the first of a free cluster).  */
    struct
      {
      size_t size;            /* Size (in blocks) of a free cluster.  */
      size_t next;            /* Index of next free cluster.  */
      size_t prev;            /* Index of previous free cluster.  */
      } free;
  } malloc_info;

/* Pointer to first block of the heap.  */
extern char *_heapbase;

/* Table indexed by block number giving per-block information.  */
extern malloc_info *_heapinfo;

/* Address to block number and vice versa.  */
#define BLOCK(A)  (((char *) (A) - _heapbase) / BLOCKSIZE + 1)
#define ADDRESS(B)      ((__ptr_t) (((B) - 1) * BLOCKSIZE + _heapbase))

/* Current search index for the heap table.  */
extern size_t _heapindex;

/* Limit of valid info table indices.  */
extern size_t _heaplimit;

/* Doubly linked lists of free fragments.  */
struct list
  {
    struct list *next;
    struct list *prev;
  };

/* Free list headers for each fragment size.  */
extern struct list _fraghead[];

/* List of blocks allocated with `memalign' (or `valloc').  */
struct alignlist
  {
    struct alignlist *next;
    __ptr_t aligned;          /* The address that memaligned returned.  */
    __ptr_t exact;            /* The address that malloc returned.  */
  };
extern struct alignlist *_aligned_blocks;

/* Instrumentation.  */
extern size_t _chunks_used;
extern size_t _bytes_used;
extern size_t _chunks_free;
extern size_t _bytes_free;

/* Internal version of `free' used in `morecore' (malloc.c). */
extern void _free_internal __P ((__ptr_t __ptr));

#endif /* _MALLOC_INTERNAL.  */

/* Underlying allocation function; successive calls should
   return contiguous pieces of memory.  */
extern __ptr_t (*__morecore) __P ((ptrdiff_t __size));

/* Default value of `__morecore'.  */
extern __ptr_t __default_morecore __P ((ptrdiff_t __size));

/* Nonzero if `malloc' has been called and done its initialization.  */
extern int __malloc_initialized;

/* Hooks for debugging versions.  */
extern void (*__free_hook) __P ((__ptr_t __ptr));
extern __ptr_t (*__malloc_hook) __P ((size_t __size));
extern __ptr_t (*__realloc_hook) __P ((__ptr_t __ptr, size_t __size));

/* Activate a standard collection of debugging hooks.  */
extern void mcheck __P ((void (*__func) __P ((void))));

/* Activate a standard collection of tracing hooks.  */
extern void mtrace __P ((void));

/* Statistics available to the user.  */
struct mstats
  {
    size_t bytes_total;       /* Total size of the heap. */
    size_t chunks_used;       /* Chunks allocated by the user. */
    size_t bytes_used;        /* Byte total of user-allocated chunks. */
    size_t chunks_free;       /* Chunks in the free list. */
    size_t bytes_free;        /* Byte total of chunks in the free list. */
  };

/* Pick up the current statistics. */
extern struct mstats mstats __P ((void));

#ifdef      __cplusplus
}
#endif

#endif /* malloc.h  */

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