/*
* Attempt at a memory allocator for the Mac, Jack Jansen, CWI, 1995-1997.
*
* Code adapted from BSD malloc, which is:
*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";*/
static char *rcsid = "$Id: malloc.c,v 1.12 2000/07/11 21:15:55 jack Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* malloc.c (Caltech) 2/21/82
* Chris Kingsley, kingsley@cit-20. Modified by Jack Jansen, CWI.
*
* This is a very fast storage allocator. It allocates blocks of a small
* number of different sizes, and keeps free lists of each size. Blocks that
* don't exactly fit are passed up to the next larger size.
*
* Blocks over a certain size are directly allocated by calling NewPtr.
*
*/
#ifdef USE_MALLOC_DEBUG
/* You may also selectively enable some of these (but some are interdependent) */
#define DEBUG
#define DEBUG2
#define MSTATS
#define RCHECK
#define VCHECK
#endif /* USE_MALLOC_DEBUG */
/*
* Set the next define if you want to return memory that is aligned to 32-byte
* boundaries. This allows 604 (and, to a lesser extent, any PPC) programs to
* make better use of the L1 cache.
*/
/* #define USE_CACHE_ALIGNED 8 /* The alignment (in 4-byte words) */
typedef unsigned char u_char;
typedef unsigned long u_long;
typedef unsigned int u_int;
typedef unsigned short u_short;
typedef u_long caddr_t;
#include <Memory.h>
#include <stdlib.h>
#include <string.h>
#ifndef NULL
#define NULL 0
#endif
static void morecore();
/*
* The overhead on a block is at least 4 bytes. When free, this space
* contains a pointer to the next free block, and the bottom two bits must
* be zero. When in use, the first byte is set to MAGIC, and the second
* byte is the size index. The remaining bytes are for alignment.
* If range checking is enabled then a second word holds the size of the
* requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
* The order of elements is critical: ov_magic must overlay the low order
* bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
*/
union overhead {
union overhead *ov_next; /* when free */
struct {
u_char ovu_magic0; /* magic number */
u_char ovu_index; /* bucket # */
u_char ovu_unused; /* unused */
u_char ovu_magic1; /* other magic number */
#ifdef RCHECK
u_short ovu_rmagic; /* range magic number */
u_long ovu_size; /* actual block size */
#endif
} ovu;
#define ov_magic0 ovu.ovu_magic0
#define ov_magic1 ovu.ovu_magic1
#define ov_index ovu.ovu_index
#define ov_rmagic ovu.ovu_rmagic
#define ov_size ovu.ovu_size
#ifdef USE_CACHE_ALIGNED
struct cachealigner {
u_long ovalign[USE_CACHE_ALIGNED];
} ovu_aligner;
#endif /* USE_CACHE_ALIGN */
};
#define MAGIC 0xef /* magic # on accounting info */
#define RMAGIC 0x5555 /* magic # on range info */
#ifdef RCHECK
#define RSLOP sizeof (u_short)
#else
#define RSLOP 0
#endif
#define OVERHEAD (sizeof(union overhead) + RSLOP)
/*
* nextf[i] is the pointer to the next free block of size 2^(i+3). The
* smallest allocatable block is 8 bytes. The overhead information
* precedes the data area returned to the user.
*/
#define NBUCKETS 11
#define MAXMALLOC (1<<(NBUCKETS+2))
static union overhead *nextf[NBUCKETS];
#ifdef MSTATS
/*
* nmalloc[i] is the difference between the number of mallocs and frees
* for a given block size.
*/
static u_int nmalloc[NBUCKETS+1];
#include <stdio.h>
#endif
#if defined(DEBUG) || defined(RCHECK) || defined(DEBUG2)
#define ASSERT(p) if (!(p)) botch(# p)
#include <stdio.h>
static
botch(s)
char *s;
{
fprintf(stderr, "\r\nmalloc assertion botched: %s\r\n", s);
(void) fflush(stderr); /* just in case user buffered it */
abort();
}
#else
#define ASSERT(p)
#endif
void *
malloc(nbytes)
size_t nbytes;
{
register union overhead *op;
register long bucket;
register unsigned amt;
/*
** First the simple case: we simple allocate big blocks directly
*/
if ( nbytes + OVERHEAD >= MAXMALLOC ) {
op = (union overhead *)NewPtr(nbytes+OVERHEAD);
if ( op == NULL )
return NULL;
op->ov_magic0 = op->ov_magic1 = MAGIC;
op->ov_index = 0xff;
#ifdef MSTATS
nmalloc[NBUCKETS]++;
#endif
#ifdef RCHECK
/*
* Record allocated size of block and
* bound space with magic numbers.
*/
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
op->ov_rmagic = RMAGIC;
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return (void *)(op+1);
}
/*
* Convert amount of memory requested into closest block size
* stored in hash buckets which satisfies request.
* Account for space used per block for accounting.
*/
#ifndef RCHECK
amt = 8; /* size of first bucket */
bucket = 0;
#else
amt = 16; /* size of first bucket */
bucket = 1;
#endif
while (nbytes + OVERHEAD > amt) {
amt <<= 1;
if (amt == 0)
return (NULL);
bucket++;
}
#ifdef DEBUG2
ASSERT( bucket < NBUCKETS );
#endif
/*
* If nothing in hash bucket right now,
* request more memory from the system.
*/
if ((op = nextf[bucket]) == NULL) {
morecore(bucket);
if ((op = nextf[bucket]) == NULL)
return (NULL);
}
/* remove from linked list */
nextf[bucket] = op->ov_next;
op->ov_magic0 = op->ov_magic1 = MAGIC;
op->ov_index = bucket;
#ifdef MSTATS
nmalloc[bucket]++;
#endif
#ifdef RCHECK
/*
* Record allocated size of block and
* bound space with magic numbers.
*/
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
op->ov_rmagic = RMAGIC;
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
#ifdef VCHECK
memset((char *)(op+1), 0x41, nbytes);
#endif
return ((char *)(op + 1));
}
/*
* Allocate more memory to the indicated bucket.
*/
static void
morecore(bucket)
int bucket;
{
register union overhead *op;
register long sz; /* size of desired block */
long amt; /* amount to allocate */
int nblks; /* how many blocks we get */
/*
* sbrk_size <= 0 only for big, FLUFFY, requests (about
* 2^30 bytes on a VAX, I think) or for a negative arg.
*/
sz = 1 << (bucket + 3);
#ifdef DEBUG2
ASSERT(sz > 0);
#endif
amt = MAXMALLOC;
nblks = amt / sz;
#ifdef DEBUG2
ASSERT(nblks*sz == amt);
#endif
#ifdef USE_CACHE_ALIGNED
op = (union overhead *)NewPtr(amt+4*USE_CACHE_ALIGNED);
#else
op = (union overhead *)NewPtr(amt);
#endif
/* no more room! */
if (op == NULL)
return;
#ifdef USE_CACHE_ALIGNED
#define ALIGN_MASK (4*USE_CACHE_ALIGNED-1)
while ((long)op & ALIGN_MASK )
op = (union overhead *)((long)op+1);
#endif /* USE_CACHE_ALIGNED */
/*
* Add new memory allocated to that on
* free list for this hash bucket.
*/
nextf[bucket] = op;
while (--nblks > 0) {
op->ov_next = (union overhead *)((caddr_t)op + sz);
op = (union overhead *)((caddr_t)op + sz);
}
op->ov_next = (union overhead *)NULL;
}
void
free(cp)
void *cp;
{
register long size;
register union overhead *op;
if (cp == NULL)
return;
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
#ifdef DEBUG
ASSERT(op->ov_magic0 == MAGIC); /* make sure it was in use */
ASSERT(op->ov_magic1 == MAGIC);
#else
if (op->ov_magic0 != MAGIC || op->ov_magic1 != MAGIC)
return; /* sanity */
#endif
#ifdef RCHECK
ASSERT(op->ov_rmagic == RMAGIC);
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
#endif
#ifdef VCHECK
memset(cp, 43, op->ov_size);
#endif
size = op->ov_index;
if ( size == 0xff ) {
#ifdef MSTATS
nmalloc[NBUCKETS]--;
#endif
DisposePtr((Ptr)op);
return;
}
ASSERT(size < NBUCKETS);
op->ov_next = nextf[size]; /* also clobbers ov_magic */
nextf[size] = op;
#ifdef MSTATS
nmalloc[size]--;
#endif
}
void *
realloc(cp, nbytes)
void *cp;
size_t nbytes;
{
int i;
union overhead *op;
int expensive;
u_long maxsize;
if (cp == NULL)
return (malloc(nbytes));
op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
#ifdef DEBUG
ASSERT(op->ov_magic0 == MAGIC); /* make sure it was in use */
ASSERT(op->ov_magic1 == MAGIC);
#else
if (op->ov_magic0 != MAGIC || op->ov_magic1 != MAGIC)
return NULL; /* sanity */
#endif
#ifdef RCHECK
ASSERT(op->ov_rmagic == RMAGIC);
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
#endif
i = op->ov_index;
/*
** First the malloc/copy cases
*/
expensive = 0;
if ( i == 0xff ) {
/* Big block. See if it has to stay big */
if (nbytes+OVERHEAD > MAXMALLOC) {
/* Yup, try to resize it first */
SetPtrSize((Ptr)op, nbytes+OVERHEAD);
if ( MemError() == 0 ) {
#ifdef RCHECK
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return cp;
}
/* Nope, failed. Take the long way */
}
maxsize = GetPtrSize((Ptr)op);
expensive = 1;
} else {
maxsize = 1 << (i+3);
if ( nbytes + OVERHEAD > maxsize )
expensive = 1;
else if ( i > 0 && nbytes + OVERHEAD < (maxsize/2) )
expensive = 1;
}
if ( expensive ) {
void *newp;
newp = malloc(nbytes);
if ( newp == NULL ) {
return NULL;
}
maxsize -= OVERHEAD;
if ( maxsize < nbytes )
nbytes = maxsize;
memcpy(newp, cp, nbytes);
free(cp);
return newp;
}
/*
** Ok, we don't have to copy, it fits as-is
*/
#ifdef RCHECK
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
#endif
return(cp);
}
#ifdef MSTATS
/*
* mstats - print out statistics about malloc
*
* Prints two lines of numbers, one showing the length of the free list
* for each size category, the second showing the number of mallocs -
* frees for each size category.
*/
mstats(s)
char *s;
{
register int i, j;
register union overhead *p;
int totfree = 0,
totused = 0;
fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
for (i = 0; i < NBUCKETS; i++) {
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
;
fprintf(stderr, " %d", j);
totfree += j * (1 << (i + 3));
}
fprintf(stderr, "\nused:\t");
for (i = 0; i < NBUCKETS; i++) {
fprintf(stderr, " %d", nmalloc[i]);
totused += nmalloc[i] * (1 << (i + 3));
}
fprintf(stderr, "\n\tTotal small in use: %d, total free: %d\n",
totused, totfree);
fprintf(stderr, "\n\tNumber of big (>%d) blocks in use: %d\n", MAXMALLOC, nmalloc[NBUCKETS]);
}
#endif
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