/* malloc.c
*
*/
#if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
# define DEBUGGING_MSTATS
#endif
#ifndef lint
# if defined(DEBUGGING) && !defined(NO_RCHECK)
# define RCHECK
# endif
/*
* malloc.c (Caltech) 2/21/82
* Chris Kingsley, kingsley@cit-20.
*
* 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. In this
* implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
* If PACK_MALLOC is defined, small blocks are 2^n bytes long.
* This is designed for use in a program that uses vast quantities of memory,
* but bombs when it runs out.
*/
#include "EXTERN.h"
#include "perl.h"
#ifdef DEBUGGING
#undef DEBUG_m
#define DEBUG_m(a) if (debug & 128) a
#endif
/* I don't much care whether these are defined in sys/types.h--LAW */
#define u_char unsigned char
#define u_int unsigned int
#define u_short unsigned short
/* 286 and atarist like big chunks, which gives too much overhead. */
#if (defined(RCHECK) || defined(I286) || defined(atarist)) && defined(PACK_MALLOC)
#undef PACK_MALLOC
#endif
/*
* The description below is applicable if PACK_MALLOC is not defined.
*
* 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 and the size of the block fits
* in two bytes, then the top two bytes hold the size of the requested block
* plus the range checking words, and the header word MINUS ONE.
*/
union overhead {
union overhead *ov_next; /* when free */
#if MEM_ALIGNBYTES > 4
double strut; /* alignment problems */
#endif
struct {
u_char ovu_magic; /* magic number */
u_char ovu_index; /* bucket # */
#ifdef RCHECK
u_short ovu_size; /* actual block size */
u_int ovu_rmagic; /* range magic number */
#endif
} ovu;
#define ov_magic ovu.ovu_magic
#define ov_index ovu.ovu_index
#define ov_size ovu.ovu_size
#define ov_rmagic ovu.ovu_rmagic
};
#ifdef DEBUGGING
static void botch _((char *s));
#endif
static void morecore _((int bucket));
static int findbucket _((union overhead *freep, int srchlen));
#define MAGIC 0xff /* magic # on accounting info */
#define RMAGIC 0x55555555 /* magic # on range info */
#ifdef RCHECK
# define RSLOP sizeof (u_int)
# ifdef TWO_POT_OPTIMIZE
# define MAX_SHORT_BUCKET 12
# else
# define MAX_SHORT_BUCKET 13
# endif
#else
# define RSLOP 0
#endif
#ifdef PACK_MALLOC
/*
* In this case it is assumed that if we do sbrk() in 2K units, we
* will get 2K aligned blocks. The bucket number of the given subblock is
* on the boundary of 2K block which contains the subblock.
* Several following bytes contain the magic numbers for the subblocks
* in the block.
*
* Sizes of chunks are powers of 2 for chunks in buckets <=
* MAX_PACKED, after this they are (2^n - sizeof(union overhead)) (to
* get alignment right).
*
* We suppose that starts of all the chunks in a 2K block are in
* different 2^n-byte-long chunks. If the top of the last chunk is
* aligned on a boundary of 2K block, this means that
* sizeof(union overhead)*"number of chunks" < 2^n, or
* sizeof(union overhead)*2K < 4^n, or n > 6 + log2(sizeof()/2)/2, if a
* chunk of size 2^n - overhead is used. Since this rules out n = 7
* for 8 byte alignment, we specialcase allocation of the first of 16
* 128-byte-long chunks.
*
* Note that with the above assumption we automatically have enough
* place for MAGIC at the start of 2K block. Note also that we
* overlay union overhead over the chunk, thus the start of the chunk
* is immediately overwritten after freeing.
*/
# define MAX_PACKED 6
# define MAX_2_POT_ALGO ((1<<(MAX_PACKED + 1)) - M_OVERHEAD)
# define TWOK_MASK ((1<<11) - 1)
# define TWOK_MASKED(x) ((u_int)(x) & ~TWOK_MASK)
# define TWOK_SHIFT(x) ((u_int)(x) & TWOK_MASK)
# define OV_INDEXp(block) ((u_char*)(TWOK_MASKED(block)))
# define OV_INDEX(block) (*OV_INDEXp(block))
# define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
(TWOK_SHIFT(block)>>(bucket + 3)) + \
(bucket > MAX_NONSHIFT ? 1 : 0)))
# define CHUNK_SHIFT 0
static u_char n_blks[11 - 3] = {224, 120, 62, 31, 16, 8, 4, 2};
static u_short blk_shift[11 - 3] = {256, 128, 64, 32,
16*sizeof(union overhead),
8*sizeof(union overhead),
4*sizeof(union overhead),
2*sizeof(union overhead),
# define MAX_NONSHIFT 2 /* Shift 64 greater than chunk 32. */
};
#else /* !PACK_MALLOC */
# define OV_MAGIC(block,bucket) (block)->ov_magic
# define OV_INDEX(block) (block)->ov_index
# define CHUNK_SHIFT 1
#endif /* !PACK_MALLOC */
# define M_OVERHEAD (sizeof(union overhead) + RSLOP)
/*
* Big allocations are often of the size 2^n bytes. To make them a
* little bit better, make blocks of size 2^n+pagesize for big n.
*/
#ifdef TWO_POT_OPTIMIZE
# ifndef PERL_PAGESIZE
# define PERL_PAGESIZE 4096
# endif
# ifndef FIRST_BIG_TWO_POT
# define FIRST_BIG_TWO_POT 14 /* 16K */
# endif
# define FIRST_BIG_BLOCK (1<<FIRST_BIG_TWO_POT) /* 16K */
/* If this value or more, check against bigger blocks. */
# define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
/* If less than this value, goes into 2^n-overhead-block. */
# define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
#endif /* TWO_POT_OPTIMIZE */
#if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
#ifndef BIG_SIZE
# define BIG_SIZE (1<<16) /* 64K */
#endif
static char *emergency_buffer;
static MEM_SIZE emergency_buffer_size;
static char *
emergency_sbrk(size)
MEM_SIZE size;
{
if (size >= BIG_SIZE) {
/* Give the possibility to recover: */
die("Out of memory during request for %i bytes", size);
/* croak may eat too much memory. */
}
if (!emergency_buffer) {
/* First offense, give a possibility to recover by dieing. */
/* No malloc involved here: */
GV **gvp = (GV**)hv_fetch(defstash, "^M", 2, 0);
SV *sv;
char *pv;
if (!gvp) gvp = (GV**)hv_fetch(defstash, "\015", 1, 0);
if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
|| (SvLEN(sv) < (1<<11) - M_OVERHEAD))
return (char *)-1; /* Now die die die... */
/* Got it, now detach SvPV: */
pv = SvPV(sv, na);
/* Check alignment: */
if (((u_int)(pv - M_OVERHEAD)) & ((1<<11) - 1)) {
PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
return (char *)-1; /* die die die */
}
emergency_buffer = pv - M_OVERHEAD;
emergency_buffer_size = SvLEN(sv) + M_OVERHEAD;
SvPOK_off(sv);
SvREADONLY_on(sv);
die("Out of memory!"); /* croak may eat too much memory. */
}
else if (emergency_buffer_size >= size) {
emergency_buffer_size -= size;
return emergency_buffer + emergency_buffer_size;
}
return (char *)-1; /* poor guy... */
}
#else /* !(defined(TWO_POT_OPTIMIZE) && defined(PERL_CORE)) */
# define emergency_sbrk(size) -1
#endif /* !(defined(TWO_POT_OPTIMIZE) && defined(PERL_CORE)) */
/*
* 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 30
static union overhead *nextf[NBUCKETS];
#ifdef USE_PERL_SBRK
#define sbrk(a) Perl_sbrk(a)
char * Perl_sbrk _((int size));
#else
extern char *sbrk();
#endif
#ifdef DEBUGGING_MSTATS
/*
* nmalloc[i] is the difference between the number of mallocs and frees
* for a given block size.
*/
static u_int nmalloc[NBUCKETS];
static u_int goodsbrk;
static u_int sbrk_slack;
static u_int start_slack;
#endif
#ifdef DEBUGGING
#define ASSERT(p) if (!(p)) botch(STRINGIFY(p)); else
static void
botch(s)
char *s;
{
PerlIO_printf(PerlIO_stderr(), "assertion botched: %s\n", s);
abort();
}
#else
#define ASSERT(p)
#endif
Malloc_t
malloc(nbytes)
register MEM_SIZE nbytes;
{
register union overhead *p;
register int bucket = 0;
register MEM_SIZE shiftr;
#if defined(DEBUGGING) || defined(RCHECK)
MEM_SIZE size = nbytes;
#endif
#ifdef PERL_CORE
#ifdef HAS_64K_LIMIT
if (nbytes > 0xffff) {
PerlIO_printf(PerlIO_stderr(),
"Allocation too large: %lx\n", (long)nbytes);
my_exit(1);
}
#endif /* HAS_64K_LIMIT */
#ifdef DEBUGGING
if ((long)nbytes < 0)
croak("panic: malloc");
#endif
#endif /* PERL_CORE */
/*
* Convert amount of memory requested into
* closest block size stored in hash buckets
* which satisfies request. Account for
* space used per block for accounting.
*/
#ifdef PACK_MALLOC
if (nbytes == 0)
nbytes = 1;
else if (nbytes > MAX_2_POT_ALGO)
#endif
{
#ifdef TWO_POT_OPTIMIZE
if (nbytes >= FIRST_BIG_BOUND)
nbytes -= PERL_PAGESIZE;
#endif
nbytes += M_OVERHEAD;
nbytes = (nbytes + 3) &~ 3;
}
shiftr = (nbytes - 1) >> 2;
/* apart from this loop, this is O(1) */
while (shiftr >>= 1)
bucket++;
/*
* If nothing in hash bucket right now,
* request more memory from the system.
*/
if (nextf[bucket] == NULL)
morecore(bucket);
if ((p = (union overhead *)nextf[bucket]) == NULL) {
#ifdef PERL_CORE
if (!nomemok) {
PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
my_exit(1);
}
#else
return (NULL);
#endif
}
#ifdef PERL_CORE
DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%lx: (%05lu) malloc %ld bytes\n",
(unsigned long)(p+1),(unsigned long)(an++),(long)size));
#endif /* PERL_CORE */
/* remove from linked list */
#ifdef RCHECK
if (*((int*)p) & (sizeof(union overhead) - 1))
PerlIO_printf(PerlIO_stderr(), "Corrupt malloc ptr 0x%lx at 0x%lx\n",
(unsigned long)*((int*)p),(unsigned long)p);
#endif
nextf[bucket] = p->ov_next;
OV_MAGIC(p, bucket) = MAGIC;
#ifndef PACK_MALLOC
OV_INDEX(p) = bucket;
#endif
#ifdef RCHECK
/*
* Record allocated size of block and
* bound space with magic numbers.
*/
nbytes = (size + M_OVERHEAD + 3) &~ 3;
if (nbytes <= 0x10000)
p->ov_size = nbytes - 1;
p->ov_rmagic = RMAGIC;
*((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
#endif
return ((Malloc_t)(p + CHUNK_SHIFT));
}
/*
* Allocate more memory to the indicated bucket.
*/
static void
morecore(bucket)
register int bucket;
{
register union overhead *op;
register int rnu; /* 2^rnu bytes will be requested */
register int nblks; /* become nblks blocks of the desired size */
register MEM_SIZE siz, needed;
int slack = 0;
if (nextf[bucket])
return;
if (bucket == (sizeof(MEM_SIZE)*8 - 3)) {
croak("Allocation too large");
}
/*
* Insure memory is allocated
* on a page boundary. Should
* make getpageize call?
*/
#ifndef atarist /* on the atari we dont have to worry about this */
op = (union overhead *)sbrk(0);
# ifndef I286
if ((UV)op & (0x7FF >> CHUNK_SHIFT)) {
slack = (0x800 >> CHUNK_SHIFT) - ((UV)op & (0x7FF >> CHUNK_SHIFT));
(void)sbrk(slack);
# if defined(DEBUGGING_MSTATS)
sbrk_slack += slack;
# endif
}
# else
/* The sbrk(0) call on the I286 always returns the next segment */
# endif
#endif /* atarist */
#if !(defined(I286) || defined(atarist))
/* take 2k unless the block is bigger than that */
rnu = (bucket <= 8) ? 11 : bucket + 3;
#else
/* take 16k unless the block is bigger than that
(80286s like large segments!), probably good on the atari too */
rnu = (bucket <= 11) ? 14 : bucket + 3;
#endif
nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
needed = (MEM_SIZE)1 << rnu;
#ifdef TWO_POT_OPTIMIZE
needed += (bucket >= (FIRST_BIG_TWO_POT - 3) ? PERL_PAGESIZE : 0);
#endif
op = (union overhead *)sbrk(needed);
/* no more room! */
if (op == (union overhead *)-1) {
op = (union overhead *)emergency_sbrk(needed);
if (op == (union overhead *)-1)
return;
}
#ifdef DEBUGGING_MSTATS
goodsbrk += needed;
#endif
/*
* Round up to minimum allocation size boundary
* and deduct from block count to reflect.
*/
#ifndef I286
# ifdef PACK_MALLOC
if ((UV)op & 0x7FF)
croak("panic: Off-page sbrk");
# endif
if ((UV)op & 7) {
op = (union overhead *)(((UV)op + 8) & ~7);
nblks--;
}
#else
/* Again, this should always be ok on an 80286 */
#endif
/*
* Add new memory allocated to that on
* free list for this hash bucket.
*/
siz = 1 << (bucket + 3);
#ifdef PACK_MALLOC
*(u_char*)op = bucket; /* Fill index. */
if (bucket <= MAX_PACKED - 3) {
op = (union overhead *) ((char*)op + blk_shift[bucket]);
nblks = n_blks[bucket];
# ifdef DEBUGGING_MSTATS
start_slack += blk_shift[bucket];
# endif
} else if (bucket <= 11 - 1 - 3) {
op = (union overhead *) ((char*)op + blk_shift[bucket]);
/* nblks = n_blks[bucket]; */
siz -= sizeof(union overhead);
} else op++; /* One chunk per block. */
#endif /* !PACK_MALLOC */
nextf[bucket] = op;
#ifdef DEBUGGING_MSTATS
nmalloc[bucket] += nblks;
#endif
while (--nblks > 0) {
op->ov_next = (union overhead *)((caddr_t)op + siz);
op = (union overhead *)((caddr_t)op + siz);
}
/* Not all sbrks return zeroed memory.*/
op->ov_next = (union overhead *)NULL;
#ifdef PACK_MALLOC
if (bucket == 7 - 3) { /* Special case, explanation is above. */
union overhead *n_op = nextf[7 - 3]->ov_next;
nextf[7 - 3] = (union overhead *)((caddr_t)nextf[7 - 3]
- sizeof(union overhead));
nextf[7 - 3]->ov_next = n_op;
}
#endif /* !PACK_MALLOC */
}
Free_t
free(mp)
Malloc_t mp;
{
register MEM_SIZE size;
register union overhead *op;
char *cp = (char*)mp;
#ifdef PACK_MALLOC
u_char bucket;
#endif
#ifdef PERL_CORE
DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%lx: (%05lu) free\n",(unsigned long)cp,(unsigned long)(an++)));
#endif /* PERL_CORE */
if (cp == NULL)
return;
op = (union overhead *)((caddr_t)cp
- sizeof (union overhead) * CHUNK_SHIFT);
#ifdef PACK_MALLOC
bucket = OV_INDEX(op);
#endif
if (OV_MAGIC(op, bucket) != MAGIC) {
static int bad_free_warn = -1;
if (bad_free_warn == -1) {
char *pbf = getenv("PERL_BADFREE");
bad_free_warn = (pbf) ? atoi(pbf) : 1;
}
if (!bad_free_warn)
return;
#ifdef RCHECK
warn("%s free() ignored",
op->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
#else
warn("Bad free() ignored");
#endif
return; /* sanity */
}
#ifdef RCHECK
ASSERT(op->ov_rmagic == RMAGIC);
if (OV_INDEX(op) <= MAX_SHORT_BUCKET)
ASSERT(*(u_int *)((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC);
op->ov_rmagic = RMAGIC - 1;
#endif
ASSERT(OV_INDEX(op) < NBUCKETS);
size = OV_INDEX(op);
op->ov_next = nextf[size];
nextf[size] = op;
}
/*
* When a program attempts "storage compaction" as mentioned in the
* old malloc man page, it realloc's an already freed block. Usually
* this is the last block it freed; occasionally it might be farther
* back. We have to search all the free lists for the block in order
* to determine its bucket: 1st we make one pass thru the lists
* checking only the first block in each; if that fails we search
* ``reall_srchlen'' blocks in each list for a match (the variable
* is extern so the caller can modify it). If that fails we just copy
* however many bytes was given to realloc() and hope it's not huge.
*/
int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
Malloc_t
realloc(mp, nbytes)
Malloc_t mp;
MEM_SIZE nbytes;
{
register MEM_SIZE onb;
union overhead *op;
char *res;
register int i;
int was_alloced = 0;
char *cp = (char*)mp;
#ifdef DEBUGGING
MEM_SIZE size = nbytes;
#endif
#ifdef PERL_CORE
#ifdef HAS_64K_LIMIT
if (nbytes > 0xffff) {
PerlIO_printf(PerlIO_stderr(),
"Reallocation too large: %lx\n", size);
my_exit(1);
}
#endif /* HAS_64K_LIMIT */
if (!cp)
return malloc(nbytes);
#ifdef DEBUGGING
if ((long)nbytes < 0)
croak("panic: realloc");
#endif
#endif /* PERL_CORE */
op = (union overhead *)((caddr_t)cp
- sizeof (union overhead) * CHUNK_SHIFT);
i = OV_INDEX(op);
if (OV_MAGIC(op, i) == MAGIC) {
was_alloced = 1;
} else {
/*
* Already free, doing "compaction".
*
* Search for the old block of memory on the
* free list. First, check the most common
* case (last element free'd), then (this failing)
* the last ``reall_srchlen'' items free'd.
* If all lookups fail, then assume the size of
* the memory block being realloc'd is the
* smallest possible.
*/
if ((i = findbucket(op, 1)) < 0 &&
(i = findbucket(op, reall_srchlen)) < 0)
i = 0;
}
onb = (1L << (i + 3)) -
#ifdef PACK_MALLOC
(i <= (MAX_PACKED - 3) ? 0 : M_OVERHEAD)
#else
M_OVERHEAD
#endif
#ifdef TWO_POT_OPTIMIZE
+ (i >= (FIRST_BIG_TWO_POT - 3) ? PERL_PAGESIZE : 0)
#endif
;
/*
* avoid the copy if same size block.
* We are not agressive with boundary cases. Note that it is
* possible for small number of cases give false negative if
* both new size and old one are in the bucket for
* FIRST_BIG_TWO_POT, but the new one is near the lower end.
*/
if (was_alloced &&
nbytes <= onb && (nbytes > ( (onb >> 1) - M_OVERHEAD )
#ifdef TWO_POT_OPTIMIZE
|| (i == (FIRST_BIG_TWO_POT - 3)
&& nbytes >= LAST_SMALL_BOUND )
#endif
)) {
#ifdef RCHECK
/*
* Record new allocated size of block and
* bound space with magic numbers.
*/
if (OV_INDEX(op) <= MAX_SHORT_BUCKET) {
/*
* Convert amount of memory requested into
* closest block size stored in hash buckets
* which satisfies request. Account for
* space used per block for accounting.
*/
nbytes += M_OVERHEAD;
nbytes = (nbytes + 3) &~ 3;
op->ov_size = nbytes - 1;
*((u_int *)((caddr_t)op + nbytes - RSLOP)) = RMAGIC;
}
#endif
res = cp;
}
else {
if ((res = (char*)malloc(nbytes)) == NULL)
return (NULL);
if (cp != res) /* common optimization */
Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
if (was_alloced)
free(cp);
}
#ifdef PERL_CORE
#ifdef DEBUGGING
if (debug & 128) {
PerlIO_printf(Perl_debug_log, "0x%lx: (%05lu) rfree\n",(unsigned long)res,(unsigned long)(an++));
PerlIO_printf(Perl_debug_log, "0x%lx: (%05lu) realloc %ld bytes\n",
(unsigned long)res,(unsigned long)(an++),(long)size);
}
#endif
#endif /* PERL_CORE */
return ((Malloc_t)res);
}
/*
* Search ``srchlen'' elements of each free list for a block whose
* header starts at ``freep''. If srchlen is -1 search the whole list.
* Return bucket number, or -1 if not found.
*/
static int
findbucket(freep, srchlen)
union overhead *freep;
int srchlen;
{
register union overhead *p;
register int i, j;
for (i = 0; i < NBUCKETS; i++) {
j = 0;
for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
if (p == freep)
return (i);
j++;
}
}
return (-1);
}
Malloc_t
calloc(elements, size)
register MEM_SIZE elements;
register MEM_SIZE size;
{
long sz = elements * size;
Malloc_t p = malloc(sz);
if (p) {
memset((void*)p, 0, sz);
}
return p;
}
#ifdef DEBUGGING_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.
*/
void
dump_mstats(s)
char *s;
{
register int i, j;
register union overhead *p;
int topbucket=0, totfree=0, total=0;
u_int nfree[NBUCKETS];
for (i=0; i < NBUCKETS; i++) {
for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
;
nfree[i] = j;
totfree += nfree[i] * (1 << (i + 3));
total += nmalloc[i] * (1 << (i + 3));
if (nmalloc[i])
topbucket = i;
}
if (s)
PerlIO_printf(PerlIO_stderr(), "Memory allocation statistics %s (buckets 8..%d)\n",
s, (1 << (topbucket + 3)) );
PerlIO_printf(PerlIO_stderr(), "%8d free:", totfree);
for (i=0; i <= topbucket; i++) {
PerlIO_printf(PerlIO_stderr(), (i<5 || i==7)?" %5d": (i<9)?" %3d":" %d", nfree[i]);
}
PerlIO_printf(PerlIO_stderr(), "\n%8d used:", total - totfree);
for (i=0; i <= topbucket; i++) {
PerlIO_printf(PerlIO_stderr(), (i<5 || i==7)?" %5d": (i<9)?" %3d":" %d", nmalloc[i] - nfree[i]);
}
PerlIO_printf(PerlIO_stderr(), "\nTotal sbrk(): %8d. Odd ends: sbrk(): %7d, malloc(): %7d bytes.\n",
goodsbrk + sbrk_slack, sbrk_slack, start_slack);
}
#else
void
dump_mstats(s)
char *s;
{
}
#endif
#endif /* lint */
#ifdef USE_PERL_SBRK
# ifdef NeXT
# define PERL_SBRK_VIA_MALLOC
# endif
# ifdef PERL_SBRK_VIA_MALLOC
# if defined(HIDEMYMALLOC) || defined(EMBEDMYMALLOC)
# undef malloc
# else
# include "Error: -DPERL_SBRK_VIA_MALLOC needs -D(HIDE|EMBED)MYMALLOC"
# endif
/* it may seem schizophrenic to use perl's malloc and let it call system */
/* malloc, the reason for that is only the 3.2 version of the OS that had */
/* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
/* end to the cores */
# define SYSTEM_ALLOC(a) malloc(a)
# endif /* PERL_SBRK_VIA_MALLOC */
static IV Perl_sbrk_oldchunk;
static long Perl_sbrk_oldsize;
# define PERLSBRK_32_K (1<<15)
# define PERLSBRK_64_K (1<<16)
char *
Perl_sbrk(size)
int size;
{
IV got;
int small, reqsize;
if (!size) return 0;
#ifdef PERL_CORE
reqsize = size; /* just for the DEBUG_m statement */
#endif
#ifdef PACK_MALLOC
size = (size + 0x7ff) & ~0x7ff;
#endif
if (size <= Perl_sbrk_oldsize) {
got = Perl_sbrk_oldchunk;
Perl_sbrk_oldchunk += size;
Perl_sbrk_oldsize -= size;
} else {
if (size >= PERLSBRK_32_K) {
small = 0;
} else {
#ifndef PERL_CORE
reqsize = size;
#endif
size = PERLSBRK_64_K;
small = 1;
}
got = (IV)SYSTEM_ALLOC(size);
#ifdef PACK_MALLOC
got = (got + 0x7ff) & ~0x7ff;
#endif
if (small) {
/* Chunk is small, register the rest for future allocs. */
Perl_sbrk_oldchunk = got + reqsize;
Perl_sbrk_oldsize = size - reqsize;
}
}
#ifdef PERL_CORE
DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%lx\n",
size, reqsize, Perl_sbrk_oldsize, got));
#endif
return (void *)got;
}
#endif /* ! defined USE_PERL_SBRK */