416 lines
11 KiB
C
416 lines
11 KiB
C
/*
|
|
* Attempt at a memory allocator for the Mac, Jack Jansen, CWI, 1995.
|
|
*
|
|
* 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 = "$Id$";
|
|
#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.
|
|
*
|
|
*/
|
|
|
|
|
|
#define DEBUG
|
|
#define DEBUG2
|
|
#define MSTATS
|
|
#define RCHECK
|
|
|
|
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>
|
|
|
|
#define NULL 0
|
|
|
|
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
|
|
};
|
|
|
|
#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, n;
|
|
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
|
|
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
|
|
op = (union overhead *)NewPtr(amt);
|
|
/* no more room! */
|
|
if (op == NULL)
|
|
return;
|
|
/*
|
|
* 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
|
|
size = op->ov_index;
|
|
if ( size == 0xff ) {
|
|
#ifdef MSTATS
|
|
nmalloc[NBUCKETS]--;
|
|
#endif
|
|
DisposPtr((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
|