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malloc.c：源码内容

#endif
{
/* same as recycled case ... */
do_check_remalloced_chunk(p, s);
/*
... plus, must obey implementation invariant that prev_inuse is
always true of any allocated chunk; i.e., that each allocated
chunk borders either a previously allocated and still in-use
chunk, or the base of its memory arena. This is ensured
by making all allocations from the the `lowest' part of any found
chunk. This does not necessarily hold however for chunks
recycled via fastbins.
*/
assert(prev_inuse(p));
}
/*
Properties of malloc_state.
This may be useful for debugging malloc, as well as detecting user
programmer errors that somehow write into malloc_state.
If you are extending or experimenting with this malloc, you can
probably figure out how to hack this routine to print out or
display chunk addresses, sizes, bins, and other instrumentation.
*/
static void do_check_malloc_state()
{
mstate av = get_malloc_state();
int i;
mchunkptr p;
mchunkptr q;
mbinptr b;
unsigned int binbit;
int empty;
unsigned int idx;
INTERNAL_SIZE_T size;
CHUNK_SIZE_T total = 0;
int max_fast_bin;
/* internal size_t must be no wider than pointer type */
assert(sizeof(INTERNAL_SIZE_T) <= sizeof(char*));
/* alignment is a power of 2 */
assert((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-1)) == 0);
/* cannot run remaining checks until fully initialized */
if (av->top == 0 || av->top == initial_top(av))
return;
/* pagesize is a power of 2 */
assert((av->pagesize & (av->pagesize-1)) == 0);
/* properties of fastbins */
/* max_fast is in allowed range */
assert(get_max_fast(av) <= request2size(MAX_FAST_SIZE));
max_fast_bin = fastbin_index(av->max_fast);
for (i = 0; i < NFASTBINS; ++i) {
p = av->fastbins[i];
/* all bins past max_fast are empty */
if (i > max_fast_bin)
assert(p == 0);
while (p != 0) {
/* each chunk claims to be inuse */
do_check_inuse_chunk(p);
total += chunksize(p);
/* chunk belongs in this bin */
assert(fastbin_index(chunksize(p)) == i);
p = p->fd;
}
}
if (total != 0)
assert(have_fastchunks(av));
else if (!have_fastchunks(av))
assert(total == 0);
/* check normal bins */
for (i = 1; i < NBINS; ++i) {
b = bin_at(av,i);
/* binmap is accurate (except for bin 1 == unsorted_chunks) */
if (i >= 2) {
binbit = get_binmap(av,i);
empty = last(b) == b;
if (!binbit)
assert(empty);
else if (!empty)
assert(binbit);
}
for (p = last(b); p != b; p = p->bk) {
/* each chunk claims to be free */
do_check_free_chunk(p);
size = chunksize(p);
total += size;
if (i >= 2) {
/* chunk belongs in bin */
idx = bin_index(size);
assert(idx == i);
/* lists are sorted */
if ((CHUNK_SIZE_T) size >= (CHUNK_SIZE_T)(FIRST_SORTED_BIN_SIZE)) {
assert(p->bk == b ||
(CHUNK_SIZE_T)chunksize(p->bk) >=
(CHUNK_SIZE_T)chunksize(p));
}
}
/* chunk is followed by a legal chain of inuse chunks */
for (q = next_chunk(p);
(q != av->top && inuse(q) &&
(CHUNK_SIZE_T)(chunksize(q)) >= MINSIZE);
q = next_chunk(q))
do_check_inuse_chunk(q);
}
}
/* top chunk is OK */
check_chunk(av->top);
/* sanity checks for statistics */
assert(total <= (CHUNK_SIZE_T)(av->max_total_mem));
assert(av->n_mmaps >= 0);
assert(av->n_mmaps <= av->max_n_mmaps);
assert((CHUNK_SIZE_T)(av->sbrked_mem) <=
(CHUNK_SIZE_T)(av->max_sbrked_mem));
assert((CHUNK_SIZE_T)(av->mmapped_mem) <=
(CHUNK_SIZE_T)(av->max_mmapped_mem));
assert((CHUNK_SIZE_T)(av->max_total_mem) >=
(CHUNK_SIZE_T)(av->mmapped_mem) + (CHUNK_SIZE_T)(av->sbrked_mem));
}
#endif
/* ----------- Routines dealing with system allocation -------------- */
/*
sysmalloc handles malloc cases requiring more memory from the system.
On entry, it is assumed that av->top does not have enough
space to service request for nb bytes, thus requiring that av->top
be extended or replaced.
*/
#if __STD_C
static Void_t* sYSMALLOc(INTERNAL_SIZE_T nb, mstate av)
#else
static Void_t* sYSMALLOc(nb, av) INTERNAL_SIZE_T nb; mstate av;
#endif
{
mchunkptr old_top; /* incoming value of av->top */
INTERNAL_SIZE_T old_size; /* its size */
char* old_end; /* its end address */
long size; /* arg to first MORECORE or mmap call */
char* brk; /* return value from MORECORE */
long correction; /* arg to 2nd MORECORE call */
char* snd_brk; /* 2nd return val */
INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of new space */
INTERNAL_SIZE_T end_misalign; /* partial page left at end of new space */
char* aligned_brk; /* aligned offset into brk */
mchunkptr p; /* the allocated/returned chunk */
mchunkptr remainder; /* remainder from allocation */
CHUNK_SIZE_T remainder_size; /* its size */
CHUNK_SIZE_T sum; /* for updating stats */
size_t pagemask = av->pagesize - 1;
/*
If there is space available in fastbins, consolidate and retry
malloc from scratch rather than getting memory from system. This
can occur only if nb is in smallbin range so we didn't consolidate
upon entry to malloc. It is much easier to handle this case here
than in malloc proper.
*/
if (have_fastchunks(av)) {
assert(in_smallbin_range(nb));
malloc_consolidate(av);
return mALLOc(nb - MALLOC_ALIGN_MASK);
}
#if HAVE_MMAP
/*
If have mmap, and the request size meets the mmap threshold, and
the system supports mmap, and there are few enough currently
allocated mmapped regions, try to directly map this request
rather than expanding top.
*/
if ((CHUNK_SIZE_T)(nb) >= (CHUNK_SIZE_T)(av->mmap_threshold) &&
(av->n_mmaps < av->n_mmaps_max)) {
char* mm; /* return value from mmap call*/
/*
Round up size to nearest page. For mmapped chunks, the overhead
is one SIZE_SZ unit larger than for normal chunks, because there
is no following chunk whose prev_size field could be used.
*/
size = (nb + SIZE_SZ + MALLOC_ALIGN_MASK + pagemask) & ~pagemask;
/* Don't try if size wraps around 0 */
if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb)) {
mm = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE));
if (mm != (char*)(MORECORE_FAILURE)) {
/*
The offset to the start of the mmapped region is stored
in the prev_size field of the chunk. This allows us to adjust
returned start address to meet alignment requirements here
and in memalign(), and still be able to compute proper
address argument for later munmap in free() and realloc().
*/
front_misalign = (INTERNAL_SIZE_T)chunk2mem(mm) & MALLOC_ALIGN_MASK;
if (front_misalign > 0) {
correction = MALLOC_ALIGNMENT - front_misalign;
p = (mchunkptr)(mm + correction);
p->prev_size = correction;
set_head(p, (size - correction) |IS_MMAPPED);
}
else {
p = (mchunkptr)mm;
p->prev_size = 0;
set_head(p, size|IS_MMAPPED);
}
/* update statistics */
if (++av->n_mmaps > av->max_n_mmaps)
av->max_n_mmaps = av->n_mmaps;
sum = av->mmapped_mem += size;
if (sum > (CHUNK_SIZE_T)(av->max_mmapped_mem))
av->max_mmapped_mem = sum;
sum += av->sbrked_mem;
if (sum > (CHUNK_SIZE_T)(av->max_total_mem))
av->max_total_mem = sum;
check_chunk(p);
return chunk2mem(p);
}
}
}
#endif
/* Record incoming configuration of top */
old_top = av->top;
old_size = chunksize(old_top);
old_end = (char*)(chunk_at_offset(old_top, old_size));
brk = snd_brk = (char*)(MORECORE_FAILURE);
/*
If not the first time through, we require old_size to be
at least MINSIZE and to have prev_inuse set.
*/
assert((old_top == initial_top(av) && old_size == 0) ||
((CHUNK_SIZE_T) (old_size) >= MINSIZE &&
prev_inuse(old_top)));
/* Precondition: not enough current space to satisfy nb request */
assert((CHUNK_SIZE_T)(old_size) < (CHUNK_SIZE_T)(nb + MINSIZE));
/* Precondition: all fastbins are consolidated */
assert(!have_fastchunks(av));
/* Request enough space for nb + pad + overhead */
size = nb + av->top_pad + MINSIZE;
/*
If contiguous, we can subtract out existing space that we hope to
combine with new space. We add it back later only if
we don't actually get contiguous space.
*/
if (contiguous(av))
size -= old_size;
/*
Round to a multiple of page size.
If MORECORE is not contiguous, this ensures that we only call it
with whole-page arguments. And if MORECORE is contiguous and
this is not first time through, this preserves page-alignment of
previous calls. Otherwise, we correct to page-align below.
*/
size = (size + pagemask) & ~pagemask;
/*
Don't try to call MORECORE if argument is so big as to appear
negative. Note that since mmap takes size_t arg, it may succeed
below even if we cannot call MORECORE.
*/
if (size > 0)
brk = (char*)(MORECORE(size));
/*
If have mmap, try using it as a backup when MORECORE fails or
cannot be used. This is worth doing on systems that have "holes" in
address space, so sbrk cannot extend to give contiguous space, but
space is available elsewhere. Note that we ignore mmap max count
and threshold limits, since the space will not be used as a
segregated mmap region.
*/
#if HAVE_MMAP
if (brk == (char*)(MORECORE_FAILURE)) {
/* Cannot merge with old top, so add its size back in */
if (contiguous(av))
size = (size + old_size + pagemask) & ~pagemask;
/* If we are relying on mmap as backup, then use larger units */
if ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(MMAP_AS_MORECORE_SIZE))
size = MMAP_AS_MORECORE_SIZE;
/* Don't try if size wraps around 0 */
if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb)) {
brk = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE));
if (brk != (char*)(MORECORE_FAILURE)) {
/* We do not need, and cannot use, another sbrk call to find end */
snd_brk = brk + size;
/*
Record that we no longer have a contiguous sbrk region.
After the first time mmap is used as backup, we do not
ever rely on contiguous space since this could incorrectly
bridge regions.
*/
set_noncontiguous(av);
}
}
}
#endif
if (brk != (char*)(MORECORE_FAILURE)) {
av->sbrked_mem += size;
/*
If MORECORE extends previous space, we can likewise extend top size.
*/
if (brk == old_end && snd_brk == (char*)(MORECORE_FAILURE)) {
set_head(old_top, (size + old_size) | PREV_INUSE);
}
/*
Otherwise, make adjustments:
* If the first time through or noncontiguous, we need to call sbrk
just to find out where the end of memory lies.
* We need to ensure that all returned chunks from malloc will meet
MALLOC_ALIGNMENT
* If there was an intervening foreign sbrk, we need to adjust sbrk
request size to account for fact that we will not be able to
combine new space with existing space in old_top.
* Almost all systems internally allocate whole pages at a time, in
which case we might as well use the whole last page of request.
So we allocate enough more memory to hit a page boundary now,
which in turn causes future contiguous calls to page-align.
*/
else {
front_misalign = 0;
end_misalign = 0;
correction = 0;
aligned_brk = brk;
/*
If MORECORE returns an address lower than we have seen before,
we know it isn't really contiguous. This and some subsequent
checks help cope with non-conforming MORECORE functions and
the presence of "foreign" calls to MORECORE from outside of
malloc or by other threads. We cannot guarantee to detect
these in all cases, but cope with the ones we do detect.
*/
if (contiguous(av) && old_size != 0 && brk < old_end) {
set_noncontiguous(av);
}
/* handle contiguous cases */
if (contiguous(av)) {
/*
We can tolerate forward non-contiguities here (usually due
to foreign calls) but treat them as part of our space for
stats reporting.
*/
if (old_size != 0)
av->sbrked_mem += brk - old_end;
/* Guarantee alignment of first new chunk made from this space */
front_misalign = (INTERNAL_SIZE_T)chunk2mem(brk) & MALLOC_ALIGN_MASK;
if (front_misalign > 0) {
/*
Skip over some bytes to arrive at an aligned position.
We don't need to specially mark these wasted front bytes.
They will never be accessed anyway because
prev_inuse of av->top (and any chunk created from its start)
is always true after initialization.
*/
correction = MALLOC_ALIGNMENT - front_misalign;
aligned_brk += correction;
}
/*
If this isn't adjacent to existing space, then we will not
be able to merge with old_top space, so must add to 2nd request.
*/
correction += old_size;
/* Extend the end address to hit a page boundary */
end_misalign = (INTERNAL_SIZE_T)(brk + size + correction);
correction += ((end_misalign + pagemask) & ~pagemask) - end_misalign;
assert(correction >= 0);
snd_brk = (char*)(MORECORE(correction));
if (snd_brk == (char*)(MORECORE_FAILURE)) {
/*
If can't allocate correction, try to at least find out current
brk. It might be enough to proceed without failing.
*/
correction = 0;
snd_brk = (char*)(MORECORE(0));
}
else if (snd_brk < brk) {
/*
If the second call gives noncontiguous space even though
it says it won't, the only course of action is to ignore
results of second call, and conservatively estimate where
the first call left us. Also set noncontiguous, so this
won't happen again, leaving at most one hole.
Note that this check is intrinsically incomplete. Because
MORECORE is allowed to give more space than we ask for,
there is no reliable way to detect a noncontiguity
producing a forward gap for the second call.
*/
snd_brk = brk + size;
correction = 0;
set_noncontiguous(av);
}
}
/* handle non-contiguous cases */
else {
/* MORECORE/mmap must correctly align */
assert(aligned_OK(chunk2mem(brk)));
/* Find out current end of memory */
if (snd_brk == (char*)(MORECORE_FAILURE)) {
snd_brk = (char*)(MORECORE(0));
av->sbrked_mem += snd_brk - brk - size;
}
}
/* Adjust top based on results of second sbrk */
if (snd_brk != (char*)(MORECORE_FAILURE)) {
av->top = (mchunkptr)aligned_brk;
set_head(av->top, (snd_brk - aligned_brk + correction) | PREV_INUSE);
av->sbrked_mem += correction;
/*
If not the first time through, we either have a
gap due to foreign sbrk or a non-contiguous region. Insert a
double fencepost at old_top to prevent consolidation with space
we don't own. These fenceposts are artificial chunks that are
marked as inuse and are in any case too small to use. We need
two to make sizes and alignments work out.
*/
if (old_size != 0) {
/*
Shrink old_top to insert fenceposts, keeping size a
multiple of MALLOC_ALIGNMENT. We know there is at least
enough space in old_top to do this.
*/
old_size = (old_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
set_head(old_top, old_size | PREV_INUSE);
/*
Note that the following assignments completely overwrite
old_top when old_size was previously MINSIZE. This is
intentional. We need the fencepost, even if old_top otherwise gets
lost.
*/
chunk_at_offset(old_top, old_size )->size =
SIZE_SZ|PREV_INUSE;
chunk_at_offset(old_top, old_size + SIZE_SZ)->size =
SIZE_SZ|PREV_INUSE;
/*
If possible, release the rest, suppressing trimming.
*/
if (old_size >= MINSIZE) {
INTERNAL_SIZE_T tt = av->trim_threshold;
av->trim_threshold = (INTERNAL_SIZE_T)(-1);
fREe(chunk2mem(old_top));
av->trim_threshold = tt;
}
}
}
}
/* Update statistics */
sum = av->sbrked_mem;
if (sum > (CHUNK_SIZE_T)(av->max_sbrked_mem))
av->max_sbrked_mem = sum;
sum += av->mmapped_mem;
if (sum > (CHUNK_SIZE_T)(av->max_total_mem))
av->max_total_mem = sum;
check_malloc_state();
/* finally, do the allocation */
p = av->top;
size = chunksize(p);
/* check that one of the above allocation paths succeeded */
if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb + MINSIZE)) {
remainder_size = size - nb;
remainder = chunk_at_offset(p, nb);
av->top = remainder;
set_head(p, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
check_malloced_chunk(p, nb);
return chunk2mem(p);
}
}
/* catch all failure paths */
MALLOC_FAILURE_ACTION;
return 0;
}
/*
sYSTRIm is an inverse of sorts to sYSMALLOc. It gives memory back
to the system (via negative arguments to sbrk) if there is unused
memory at the `high' end of the malloc pool. It is called
automatically by free() when top space exceeds the trim
threshold. It is also called by the public malloc_trim routine. It
returns 1 if it actually released any memory, else 0.
*/
#if __STD_C
static int sYSTRIm(size_t pad, mstate av)
#else
static int sYSTRIm(pad, av) size_t pad; mstate av;
#endif
{
long top_size; /* Amount of top-most memory */
long extra; /* Amount to release */
long released; /* Amount actually released */
char* current_brk; /* address returned by pre-check sbrk call */
char* new_brk; /* address returned by post-check sbrk call */
size_t pagesz;
pagesz = av->pagesize;
top_size = chunksize(av->top);
/* Release in pagesize units, keeping at least one page */
extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
if (extra > 0) {
/*
Only proceed if end of memory is where we last set it.
This avoids problems if there were foreign sbrk calls.
*/
current_brk = (char*)(MORECORE(0));
if (current_brk == (char*)(av->top) + top_size) {
/*
Attempt to release memory. We ignore MORECORE return value,
and instead call again to find out where new end of memory is.
This avoids problems if first call releases less than we asked,
of if failure somehow altered brk value. (We could still
encounter problems if it altered brk in some very bad way,
but the only thing we can do is adjust anyway, which will cause
some downstream failure.)
*/
MORECORE(-extra);
new_brk = (char*)(MORECORE(0));
if (new_brk != (char*)MORECORE_FAILURE) {
released = (long)(current_brk - new_brk);
if (released != 0) {
/* Success. Adjust top. */
av->sbrked_mem -= released;
set_head(av->top, (top_size - released) | PREV_INUSE);
check_malloc_state();
return 1;
}
}
}
}
return 0;
}
/*
------------------------------ malloc ------------------------------
*/
#if __STD_C
Void_t* mALLOc(size_t bytes)
#else
Void_t* mALLOc(bytes) size_t bytes;
#endif
{
mstate av = get_malloc_state();
INTERNAL_SIZE_T nb; /* normalized request size */
unsigned int idx; /* associated bin index */
mbinptr bin; /* associated bin */
mfastbinptr* fb; /* associated fastbin */
mchunkptr victim; /* inspected/selected chunk */
INTERNAL_SIZE_T size; /* its size */
int victim_index; /* its bin index */
mchunkptr remainder; /* remainder from a split */
CHUNK_SIZE_T remainder_size; /* its size */
unsigned int block; /* bit map traverser */
unsigned int bit; /* bit map traverser */
unsigned int map; /* current word of binmap */
mchunkptr fwd; /* misc temp for linking */
mchunkptr bck; /* misc temp for linking */
/*
Convert request size to internal form by adding SIZE_SZ bytes
overhead plus possibly more to obtain necessary alignment and/or
to obtain a size of at least MINSIZE, the smallest allocatable
size. Also, checked_request2size traps (returning 0) request sizes
that are so large that they wrap around zero when padded and
aligned.
*/
checked_request2size(bytes, nb);
/*
Bypass search if no frees yet
*/
if (!have_anychunks(av)) {
if (av->max_fast == 0) /* initialization check */
malloc_consolidate(av);
goto use_top;
}
/*
If the size qualifies as a fastbin, first check corresponding bin.
*/
if ((CHUNK_SIZE_T)(nb) <= (CHUNK_SIZE_T)(av->max_fast)) {
fb = &(av->fastbins[(fastbin_index(nb))]);
if ( (victim = *fb) != 0) {
*fb = victim->fd;
check_remalloced_chunk(victim, nb);
return chunk2mem(victim);
}
}
/*
If a small request, check regular bin. Since these "smallbins"
hold one size each, no searching within bins is necessary.
(For a large request, we need to wait until unsorted chunks are
processed to find best fit. But for small ones, fits are exact
anyway, so we can check now, which is faster.)
*/
if (in_smallbin_range(nb)) {
idx = smallbin_index(nb);
bin = bin_at(av,idx);
if ( (victim = last(bin)) != bin) {
bck = victim->bk;
set_inuse_bit_at_offset(victim, nb);
bin->bk = bck;
bck->fd = bin;
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
}
/*
If this is a large request, consolidate fastbins before continuing.
While it might look excessive to kill all fastbins before
even seeing if there is space available, this avoids
fragmentation problems normally associated with fastbins.
Also, in practice, programs tend to have runs of either small or
large requests, but less often mixtures, so consolidation is not
invoked all that often in most programs. And the programs that
it is called frequently in otherwise tend to fragment.
*/
else {
idx = largebin_index(nb);
if (have_fastchunks(av))
malloc_consolidate(av);
}
/*
Process recently freed or remaindered chunks, taking one only if
it is exact fit, or, if this a small request, the chunk is remainder from
the most recent non-exact fit. Place other traversed chunks in
bins. Note that this step is the only place in any routine where
chunks are placed in bins.
*/
while ( (victim = unsorted_chunks(av)->bk) != unsorted_chunks(av)) {
bck = victim->bk;
size = chunksize(victim);
/*
If a small request, try to use last remainder if it is the
only chunk in unsorted bin. This helps promote locality for
runs of consecutive small requests. This is the only
exception to best-fit, and applies only when there is
no exact fit for a small chunk.
*/
if (in_smallbin_range(nb) &&
bck == unsorted_chunks(av) &&
victim == av->last_remainder &&
(CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb + MINSIZE)) {
/* split and reattach remainder */
remainder_size = size - nb;
remainder = chunk_at_offset(victim, nb);
unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
av->last_remainder = remainder;
remainder->bk = remainder->fd = unsorted_chunks(av);
set_head(victim, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
set_foot(remainder, remainder_size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
/* remove from unsorted list */
unsorted_chunks(av)->bk = bck;
bck->fd = unsorted_chunks(av);
/* Take now instead of binning if exact fit */
if (size == nb) {
set_inuse_bit_at_offset(victim, size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
/* place chunk in bin */
if (in_smallbin_range(size)) {
victim_index = smallbin_index(size);
bck = bin_at(av, victim_index);
fwd = bck->fd;
}
else {
victim_index = largebin_index(size);
bck = bin_at(av, victim_index);
fwd = bck->fd;
if (fwd != bck) {
/* if smaller than smallest, place first */
if ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(bck->bk->size)) {
fwd = bck;
bck = bck->bk;
}
else if ((CHUNK_SIZE_T)(size) >=
(CHUNK_SIZE_T)(FIRST_SORTED_BIN_SIZE)) {
/* maintain large bins in sorted order */
size |= PREV_INUSE; /* Or with inuse bit to speed comparisons */
while ((CHUNK_SIZE_T)(size) < (CHUNK_SIZE_T)(fwd->size))
fwd = fwd->fd;
bck = fwd->bk;
}
}
}
mark_bin(av, victim_index);
victim->bk = bck;
victim->fd = fwd;
fwd->bk = victim;
bck->fd = victim;
}
/*
If a large request, scan through the chunks of current bin to
find one that fits. (This will be the smallest that fits unless
FIRST_SORTED_BIN_SIZE has been changed from default.) This is
the only step where an unbounded number of chunks might be
scanned without doing anything useful with them. However the
lists tend to be short.
*/
if (!in_smallbin_range(nb)) {
bin = bin_at(av, idx);
for (victim = last(bin); victim != bin; victim = victim->bk) {
size = chunksize(victim);
if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb)) {
remainder_size = size - nb;
unlink(victim, bck, fwd);
/* Exhaust */
if (remainder_size < MINSIZE) {
set_inuse_bit_at_offset(victim, size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
/* Split */
else {
remainder = chunk_at_offset(victim, nb);
unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
remainder->bk = remainder->fd = unsorted_chunks(av);
set_head(victim, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
set_foot(remainder, remainder_size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
}
}
}
/*
Search for a chunk by scanning bins, starting with next largest
bin. This search is strictly by best-fit; i.e., the smallest
(with ties going to approximately the least recently used) chunk
that fits is selected.
The bitmap avoids needing to check that most blocks are nonempty.
*/
++idx;
bin = bin_at(av,idx);
block = idx2block(idx);
map = av->binmap[block];
bit = idx2bit(idx);
for (;;) {
/* Skip rest of block if there are no more set bits in this block. */
if (bit > map || bit == 0) {
do {
if (++block >= BINMAPSIZE) /* out of bins */
goto use_top;
} while ( (map = av->binmap[block]) == 0);
bin = bin_at(av, (block << BINMAPSHIFT));
bit = 1;
}
/* Advance to bin with set bit. There must be one. */
while ((bit & map) == 0) {
bin = next_bin(bin);
bit <<= 1;
assert(bit != 0);
}
/* Inspect the bin. It is likely to be non-empty */
victim = last(bin);
/* If a false alarm (empty bin), clear the bit. */
if (victim == bin) {
av->binmap[block] = map &= ~bit; /* Write through */
bin = next_bin(bin);
bit <<= 1;
}
else {
size = chunksize(victim);
/* We know the first chunk in this bin is big enough to use. */
assert((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb));
remainder_size = size - nb;
/* unlink */
bck = victim->bk;
bin->bk = bck;
bck->fd = bin;
/* Exhaust */
if (remainder_size < MINSIZE) {
set_inuse_bit_at_offset(victim, size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
/* Split */
else {
remainder = chunk_at_offset(victim, nb);
unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
remainder->bk = remainder->fd = unsorted_chunks(av);
/* advertise as last remainder */
if (in_smallbin_range(nb))
av->last_remainder = remainder;
set_head(victim, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
set_foot(remainder, remainder_size);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
}
}
use_top:
/*
If large enough, split off the chunk bordering the end of memory
(held in av->top). Note that this is in accord with the best-fit
search rule. In effect, av->top is treated as larger (and thus
less well fitting) than any other available chunk since it can
be extended to be as large as necessary (up to system
limitations).
We require that av->top always exists (i.e., has size >=
MINSIZE) after initialization, so if it would otherwise be
exhuasted by current request, it is replenished. (The main
reason for ensuring it exists is that we may need MINSIZE space
to put in fenceposts in sysmalloc.)
*/
victim = av->top;
size = chunksize(victim);
if ((CHUNK_SIZE_T)(size) >= (CHUNK_SIZE_T)(nb + MINSIZE)) {
remainder_size = size - nb;
remainder = chunk_at_offset(victim, nb);
av->top = remainder;
set_head(victim, nb | PREV_INUSE);
set_head(remainder, remainder_size | PREV_INUSE);
check_malloced_chunk(victim, nb);
return chunk2mem(victim);
}
/*
If no space in top, relay to handle system-dependent cases
*/
return sYSMALLOc(nb, av);
}
/*
------------------------------ free ------------------------------
*/
#if __STD_C
void fREe(Void_t* mem)
#else
void fREe(mem) Void_t* mem;
#endif
{
mstate av = get_malloc_state();
mchunkptr p; /* chunk corresponding to mem */
INTERNAL_SIZE_T size; /* its size */
mfastbinptr* fb; /* associated fastbin */
mchunkptr nextchunk; /* next contiguous chunk */
INTERNAL_SIZE_T nextsize; /* its size */
int nextinuse; /* true if nextchunk is used */
INTERNAL_SIZE_T prevsize; /* size of previous contiguous chunk */
mchunkptr bck; /* misc temp for linking */
mchunkptr fwd; /* misc temp for linking */
/* free(0) has no effect */
if (mem != 0) {
p = mem2chunk(mem);
size = chunksize(p);
check_inuse_chunk(p);
/*
If eligible, place chunk on a fastbin so it can be found
and used quickly in malloc.
*/
if ((CHUNK_SIZE_T)(size) <= (CHUNK_SIZE_T)(av->max_fast)
#if TRIM_FASTBINS
/*
If TRIM_FASTBINS set, don't place chunks
bordering top into fastbins
*/
&& (chunk_at_offset(p, size) != av->top)
#endif
) {
set_fastchunks(av);
fb = &(av->fastbins[fastbin_index(size)]);
p->fd = *fb;
*fb = p;
}
/*
Consolidate other non-mmapped chunks as they arrive.
*/
else if (!chunk_is_mmapped(p)) {
set_anychunks(av);
nextchunk = chunk_at_offset(p, size);
nextsize = chunksize(nextchunk);
/* consolidate backward */
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
/* get and clear inuse bit */
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
set_head(nextchunk, nextsize);
/* consolidate forward */
if (!nextinuse) {
unlink(nextchunk, bck, fwd);
size += nextsize;
}
/*
Place the chunk in unsorted chunk list. Chunks are
not placed into regular bins until after they have
been given one chance to be used in malloc.
*/
bck = unsorted_chunks(av);
fwd = bck->fd;
p->bk = bck;
p->fd = fwd;
bck->fd = p;
fwd->bk = p;
set_head(p, size | PREV_INUSE);
set_foot(p, size);
check_free_chunk(p);
}
/*
If the chunk borders the current high end of memory,
consolidate into top
*/
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
check_chunk(p);
}
/*
If freeing a large space, consolidate possibly-surrounding
chunks. Then, if the total unused topmost memory exceeds trim
threshold, ask malloc_trim to reduce top.
Unless max_fast is 0, we don't know if there are fastbins
bordering top, so we cannot tell for sure whether threshold
has been reached unless fastbins are consolidated. But we
don't want to consolidate on each free. As a compromise,
consolidation is performed if FASTBIN_CONSOLIDATION_THRESHOLD
is reached.
*/
if ((CHUNK_SIZE_T)(size) >= FASTBIN_CONSOLIDATION_THRESHOLD) {
if (have_fastchunks(av))
malloc_consolidate(av);
#ifndef MORECORE_CANNOT_TRIM
if ((CHUNK_SIZE_T)(chunksize(av->top)) >=
(CHUNK_SIZE_T)(av->trim_threshold))
sYSTRIm(av->top_pad, av);
#endif
}
}
/*
If the chunk was allocated via mmap, release via munmap()
Note that if HAVE_MMAP is false but chunk_is_mmapped is
true, then user must have overwritten memory. There's nothing
we can do to catch this error unless DEBUG is set, in which case
check_inuse_chunk (above) will have triggered error.
*/
else {
#if HAVE_MMAP
int ret;
INTERNAL_SIZE_T offset = p->prev_size;
av->n_mmaps--;
av->mmapped_mem -= (size + offset);
ret = munmap((char*)p - offset, size + offset);
/* munmap returns non-zero on failure */
assert(ret == 0);
#endif
}
}
}
/*
------------------------- malloc_consolidate -------------------------
malloc_consolidate is a specialized version of free() that tears
down chunks held in fastbins. Free itself cannot be used for this
purpose since, among other things, it might place chunks back onto
fastbins. So, instead, we need to use a minor variant of the same
code.
Also, because this routine needs to be called the first time through
malloc anyway, it turns out to be the perfect place to trigger
initialization code.
*/
#if __STD_C
static void malloc_consolidate(mstate av)
#else
static void malloc_consolidate(av) mstate av;
#endif
{
mfastbinptr* fb; /* current fastbin being consolidated */
mfastbinptr* maxfb; /* last fastbin (for loop control) */
mchunkptr p; /* current chunk being consolidated */
mchunkptr nextp; /* next chunk to consolidate */
mchunkptr unsorted_bin; /* bin header */
mchunkptr first_unsorted; /* chunk to link to */
/* These have same use as in free() */
mchunkptr nextchunk;
INTERNAL_SIZE_T size;
INTERNAL_SIZE_T nextsize;
INTERNAL_SIZE_T prevsize;
int nextinuse;
mchunkptr bck;
mchunkptr fwd;
/*
If max_fast is 0, we know that av hasn't
yet been initialized, in which case do so below
*/
if (av->max_fast != 0) {
clear_fastchunks(av);
unsorted_bin = unsorted_chunks(av);
/*
Remove each chunk from fast bin and consolidate it, placing it
then in unsorted bin. Among other reasons for doing this,
placing in unsorted bin avoids needing to calculate actual bins
until malloc is sure that chunks aren't immediately going to be
reused anyway.
*/
maxfb = &(av->fastbins[fastbin_index(av->max_fast)]);
fb = &(av->fastbins[0]);
do {
if ( (p = *fb) != 0) {
*fb = 0;
do {
check_inuse_chunk(p);
nextp = p->fd;
/* Slightly streamlined version of consolidation code in free() */
size = p->size & ~PREV_INUSE;
nextchunk = chunk_at_offset(p, size);
nextsize = chunksize(nextchunk);
if (!prev_inuse(p)) {
prevsize = p->prev_size;
size += prevsize;
p = chunk_at_offset(p, -((long) prevsize));
unlink(p, bck, fwd);
}
if (nextchunk != av->top) {
nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
set_head(nextchunk, nextsize);
if (!nextinuse) {
size += nextsize;
unlink(nextchunk, bck, fwd);
}
first_unsorted = unsorted_bin->fd;
unsorted_bin->fd = p;
first_unsorted->bk = p;
set_head(p, size | PREV_INUSE);
p->bk = unsorted_bin;
p->fd = first_unsorted;
set_foot(p, size);
}
else {
size += nextsize;
set_head(p, size | PREV_INUSE);
av->top = p;
}
} while ( (p = nextp) != 0);
}
} while (fb++ != maxfb);
}
else {
malloc_init_state(av);
check_malloc_state();
}
}
/*
------------------------------ realloc ------------------------------
*/
#if __STD_C
Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
#else
Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
#endif
{
mstate av = get_malloc_state();
INTERNAL_SIZE_T nb; /* padded request size */
mchunkptr oldp; /* chunk corresponding to oldmem */
INTERNAL_SIZE_T oldsize; /* its size */
mchunkptr newp; /* chunk to return */
INTERNAL_SIZE_T newsize; /* its size */
Void_t* newmem; /* corresponding user mem */
mchunkptr next; /* next contiguous chunk after oldp */
mchunkptr remainder; /* extra space at end of newp */
CHUNK_SIZE_T remainder_size; /* its size */
mchunkptr bck; /* misc temp for linking */
mchunkptr fwd; /* misc temp for linking */
CHUNK_SIZE_T copysize; /* bytes to copy */
unsigned int ncopies; /* INTERNAL_SIZE_T words to copy */
INTERNAL_SIZE_T* s; /* copy source */
INTERNAL_SIZE_T* d; /* copy destination */
#ifdef REALLOC_ZERO_BYTES_FREES
if (bytes == 0) {
fREe(oldmem);
return 0;
}
#endif
/* realloc of null is supposed to be same as malloc */
if (oldmem == 0) return mALLOc(bytes);
checked_request2size(bytes, nb);
oldp = mem2chunk(oldmem);
oldsize = chunksize(oldp);
check_inuse_chunk(oldp);
if (!chunk_is_mmapped(oldp)) {
if ((CHUNK_SIZE_T)(oldsize) >= (CHUNK_SIZE_T)(nb)) {
/* already big enough; split below */
newp = oldp;
newsize = oldsize;
}
else {
next = chunk_at_offset(oldp, oldsize);
/* Try to expand forward into top */
if (next == av->top &&
(CHUNK_SIZE_T)(newsize = oldsize + chunksize(next)) >=
(CHUNK_SIZE_T)(nb + MINSIZE)) {
set_head_size(oldp, nb);
av->top = chunk_at_offset(oldp, nb);
set_head(av->top, (newsize - nb) | PREV_INUSE);
return chunk2mem(oldp);
}
/* Try to expand forward into next chunk; split off remainder below */
else if (next != av->top &&
!inuse(next) &&
(CHUNK_SIZE_T)(newsize = oldsize + chunksize(next)) >=
(CHUNK_SIZE_T)(nb)) {
newp = oldp;
unlink(next, bck, fwd);
}
/* allocate, copy, free */
else {
newmem = mALLOc(nb - MALLOC_ALIGN_MASK);
if (newmem == 0)
return 0; /* propagate failure */
newp = mem2chunk(newmem);
newsize = chunksize(newp);
/*
Avoid copy if newp is next chunk after oldp.
*/
if (newp == next) {
newsize += oldsize;
newp = oldp;
}
else {
/*
Unroll copy of <= 36 bytes (72 if 8byte sizes)
We know that contents have an odd number of
INTERNAL_SIZE_T-sized words; minimally 3.
*/
copysize = oldsize - SIZE_SZ;
s = (INTERNAL_SIZE_T*)(oldmem);
d = (INTERNAL_SIZE_T*)(newmem);
ncopies = copysize / sizeof(INTERNAL_SIZE_T);
assert(ncopies >= 3);
if (ncopies > 9)
MALLOC_COPY(d, s, copysize);
else {
*(d+0) = *(s+0);
*(d+1) = *(s+1);
*(d+2) = *(s+2);
if (ncopies > 4) {
*(d+3) = *(s+3);
*(d+4) = *(s+4);
if (ncopies > 6) {
*(d+5) = *(s+5);
*(d+6) = *(s+6);
if (ncopies > 8) {
*(d+7) = *(s+7);
*(d+8) = *(s+8);
}
}
}
}
fREe(oldmem);
check_inuse_chunk(newp);
return chunk2mem(newp);
}
}
}
/* If possible, free extra space in old or extended chunk */
assert((CHUNK_SIZE_T)(newsize) >= (CHUNK_SIZE_T)(nb));
remainder_size = newsize - nb;
if (remainder_size < MINSIZE) { /* not enough extra to split off */
set_head_size(newp, newsize);
set_inuse_bit_at_offset(newp, newsize);
}
else { /* split remainder */
remainder = chunk_at_offset(newp, nb);
set_head_size(newp, nb);
set_head(remainder, remainder_size | PREV_INUSE);
/* Mark remainder as inuse so free() won't complain */
set_inuse_bit_at_offset(remainder, remainder_size);
fREe(chunk2mem(remainder));
}
check_inuse_chunk(newp);
return chunk2mem(newp);
}
/*
Handle mmap cases
*/
else {
#if HAVE_MMAP
#if HAVE_MREMAP
INTERNAL_SIZE_T offset = oldp->prev_size;
size_t pagemask = av->pagesize - 1;
char *cp;
CHUNK_SIZE_T sum;
/* Note the extra SIZE_SZ overhead */
newsize = (nb + offset + SIZE_SZ + pagemask) & ~pagemask;
/* don't need to remap if still within same page */
if (oldsize == newsize - offset)
return oldmem;
cp = (char*)mremap((char*)oldp - offset, oldsize + offset, newsize, 1);
if (cp != (char*)MORECORE_FAILURE) {
newp = (mchunkptr)(cp + offset);
set_head(newp, (newsize - offset)|IS_MMAPPED);
assert(aligned_OK(chunk2mem(newp)));
assert((newp->prev_size == offset));
/* update statistics */
sum = av->mmapped_mem += newsize - oldsize;
if (sum > (CHUNK_SIZE_T)(av->max_mmapped_mem))
av->max_mmapped_mem = sum;
sum += av->sbrked_mem;
if (sum > (CHUNK_SIZE_T)(av->max_total_mem))
av->max_total_mem = sum;
return chunk2mem(newp);
}
#endif
/* Note the extra SIZE_SZ overhead. */
if ((CHUNK_SIZE_T)(oldsize) >= (CHUNK_SIZE_T)(nb + SIZE_SZ))
newmem = oldmem; /* do nothing */
else {
/* Must alloc, copy, free. */
newmem = mALLOc(nb - MALLOC_ALIGN_MASK);
if (newmem != 0) {
MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
fREe(oldmem);
}
}
return newmem;
#else
/* If !HAVE_MMAP, but chunk_is_mmapped, user must have overwritten mem */
check_malloc_state();
MALLOC_FAILURE_ACTION;
return 0;
#endif
}
}
/*
------------------------------ memalign ------------------------------
*/
#if __STD_C
Void_t* mEMALIGn(size_t alignment, size_t bytes)
#else
Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
#endif
{
INTERNAL_SIZE_T nb; /* padded request size */
char* m; /* memory returned by malloc call */
mchunkptr p; /* corresponding chunk */
char* brk; /* alignment point within p */
mchunkptr newp; /* chunk to return */
INTERNAL_SIZE_T newsize; /* its size */
INTERNAL_SIZE_T leadsize; /* leading space before alignment point */
mchunkptr remainder; /* spare room at end to split off */
CHUNK_SIZE_T remainder_size; /* its size */
INTERNAL_SIZE_T size;
/* If need less alignment than we give anyway, just relay to malloc */
if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
/* Otherwise, ensure that it is at least a minimum chunk size */
if (alignment < MINSIZE) alignment = MINSIZE;
/* Make sure alignment is power of 2 (in case MINSIZE is not). */
if ((alignment & (alignment - 1)) != 0) {
size_t a = MALLOC_ALIGNMENT * 2;
while ((CHUNK_SIZE_T)a < (CHUNK_SIZE_T)alignment) a <<= 1;
alignment = a;
}
checked_request2size(bytes, nb);
/*
Strategy: find a spot within that chunk that meets the alignment
request, and then possibly free the leading and trailing space.
*/
/* Call malloc with worst case padding to hit alignment. */
m = (char*)(mALLOc(nb + alignment + MINSIZE));
if (m == 0) return 0; /* propagate failure */
p = mem2chunk(m);
if ((((PTR_UINT)(m)) % alignment) != 0) { /* misaligned */
/*
Find an aligned spot inside chunk. Since we need to give back
leading space in a chunk of at least MINSIZE, if the first
calculation places us at a spot with less than MINSIZE leader,
we can move to the next aligned spot -- we've allocated enough
total room so that this is always possible.
*/
brk = (char*)mem2chunk((PTR_UINT)(((PTR_UINT)(m + alignment - 1)) &
-((signed long) alignment)));
if ((CHUNK_SIZE_T)(brk - (char*)(p)) < MINSIZE)
brk += alignment;
newp = (mchunkptr)brk;
leadsize = brk - (char*)(p);
newsize = chunksize(p) - leadsize;
/* For mmapped chunks, just adjust offset */
if (chunk_is_mmapped(p)) {
newp->prev_size = p->prev_size + leadsize;
set_head(newp, newsize|IS_MMAPPED);
return chunk2mem(newp);
}
/* Otherwise, give back leader, use the rest */
set_head(newp, newsize | PREV_INUSE);
set_inuse_bit_at_offset(newp, newsize);
set_head_size(p, leadsize);
fREe(chunk2mem(p));
p = newp;
assert (newsize >= nb &&
(((PTR_UINT)(chunk2mem(p))) % alignment) == 0);
}
/* Also give back spare room at the end */
if (!chunk_is_mmapped(p)) {
size = chunksize(p);
if ((CHUNK_SIZE_T)(size) > (CHUNK_SIZE_T)(nb + MINSIZE)) {
remainder_size = size - nb;
remainder = chunk_at_offset(p, nb);
set_head(remainder, remainder_size | PREV_INUSE);
set_head_size(p, nb);
fREe(chunk2mem(remainder));
}
}
check_inuse_chunk(p);
return chunk2mem(p);
}
/*
------------------------------ calloc ------------------------------
*/
#if __STD_C
Void_t* cALLOc(size_t n_elements, size_t elem_size)
#else
Void_t* cALLOc(n_elements, elem_size) size_t n_elements; size_t elem_size;
#endif
{
mchunkptr p;
CHUNK_SIZE_T clearsize;
CHUNK_SIZE_T nclears;
INTERNAL_SIZE_T* d;
Void_t* mem = mALLOc(n_elements * elem_size);
if (mem != 0) {
p = mem2chunk(mem);
if (!chunk_is_mmapped(p))
{
/*
Unroll clear of <= 36 bytes (72 if 8byte sizes)
We know that contents have an odd number of
INTERNAL_SIZE_T-sized words; minimally 3.
*/
d = (INTERNAL_SIZE_T*)mem;
clearsize = chunksize(p) - SIZE_SZ;
nclears = clearsize / sizeof(INTERNAL_SIZE_T);
assert(nclears >= 3);
if (nclears > 9)
MALLOC_ZERO(d, clearsize);
else {
*(d+0) = 0;
*(d+1) = 0;
*(d+2) = 0;
if (nclears > 4) {
*(d+3) = 0;
*(d+4) = 0;
if (nclears > 6) {
*(d+5) = 0;
*(d+6) = 0;
if (nclears > 8) {
*(d+7) = 0;
*(d+8) = 0;
}
}
}
}
}
#if ! MMAP_CLEARS
else
{
d = (INTERNAL_SIZE_T*)mem;
/*
Note the additional SIZE_SZ
*/
clearsize = chunksize(p) - 2*SIZE_SZ;
MALLOC_ZERO(d, clearsize);
}
#endif
}
return mem;
}
/*
------------------------------ valloc ------------------------------
*/
#if __STD_C
Void_t* vALLOc(size_t bytes)
#else
Void_t* vALLOc(bytes) size_t bytes;
#endif
{
/* Ensure initialization */
mstate av = get_malloc_state();
if (av->max_fast == 0) malloc_consolidate(av);
return mEMALIGn(av->pagesize, bytes);
}
#if 0
/*
------------------------------ cfree ------------------------------
*/
#if __STD_C
void cFREe(Void_t *mem)
#else
void cFREe(mem) Void_t *mem;
#endif
{
fREe(mem);
}
/*
------------------------- independent_calloc -------------------------
*/
#if __STD_C
Void_t** iCALLOc(size_t n_elements, size_t elem_size, Void_t* chunks[])
#else
Void_t** iCALLOc(n_elements, elem_size, chunks) size_t n_elements; size_t elem_size; Void_t* chunks[];
#endif
{
size_t sz = elem_size; /* serves as 1-element array */
/* opts arg of 3 means all elements are same size, and should be cleared */
return iALLOc(n_elements, &sz, 3, chunks);
}
/*
------------------------- independent_comalloc -------------------------
*/
#if __STD_C
Void_t** iCOMALLOc(size_t n_elements, size_t sizes[], Void_t* chunks[])
#else
Void_t** iCOMALLOc(n_elements, sizes, chunks) size_t n_elements; size_t sizes[]; Void_t* chunks[];
#endif
{
return iALLOc(n_elements, sizes, 0, chunks);
}
/*
------------------------------ ialloc ------------------------------
ialloc provides common support for independent_X routines, handling all of
the combinations that can result.
The opts arg has:
bit 0 set if all elements are same size (using sizes[0])
bit 1 set if elements should be zeroed
*/
#if __STD_C
static Void_t** iALLOc(size_t n_elements,
size_t* sizes,
int opts,
Void_t* chunks[])
#else
static Void_t** iALLOc(n_elements, sizes, opts, chunks) size_t n_elements; size_t* sizes; int opts; Void_t* chunks[];
#endif
{
mstate av = get_malloc_state();
INTERNAL_SIZE_T element_size; /* chunksize of each element, if all same */
INTERNAL_SIZE_T contents_size; /* total size of elements */
INTERNAL_SIZE_T array_size; /* request size of pointer array */
Void_t* mem; /* malloced aggregate space */
mchunkptr p; /* corresponding chunk */
INTERNAL_SIZE_T remainder_size; /* remaining bytes while splitting */
Void_t** marray; /* either "chunks" or malloced ptr array */
mchunkptr array_chunk; /* chunk for malloced ptr array */
int mmx; /* to disable mmap */
INTERNAL_SIZE_T size;
size_t i;
/* Ensure initialization */
if (av->max_fast == 0) malloc_consolidate(av);
/* compute array length, if needed */
if (chunks != 0) {
if (n_elements == 0)
return chunks; /* nothing to do */
marray = chunks;
array_size = 0;
}
else {
/* if empty req, must still return chunk representing empty array */
if (n_elements == 0)
return (Void_t**) mALLOc(0);
marray = 0;
array_size = request2size(n_elements * (sizeof(Void_t*)));
}
/* compute total element size */
if (opts & 0x1) { /* all-same-size */
element_size = request2size(*sizes);
contents_size = n_elements * element_size;
}
else { /* add up all the sizes */
element_size = 0;
contents_size = 0;
for (i = 0; i != n_elements; ++i)
contents_size += request2size(sizes[i]);
}
/* subtract out alignment bytes from total to minimize overallocation */
size = contents_size + array_size - MALLOC_ALIGN_MASK;
/*
Allocate the aggregate chunk.
But first disable mmap so malloc won't use it, since
we would not be able to later free/realloc space internal
to a segregated mmap region.
*/
mmx = av->n_mmaps_max; /* disable mmap */
av->n_mmaps_max = 0;
mem = mALLOc(size);
av->n_mmaps_max = mmx; /* reset mmap */
if (mem == 0)
return 0;
p = mem2chunk(mem);
assert(!chunk_is_mmapped(p));
remainder_size = chunksize(p);
if (opts & 0x2) { /* optionally clear the elements */
MALLOC_ZERO(mem, remainder_size - SIZE_SZ - array_size);
}
/* If not provided, allocate the pointer array as final part of chunk */
if (marray == 0) {
array_chunk = chunk_at_offset(p, contents_size);
marray = (Void_t**) (chunk2mem(array_chunk));
set_head(array_chunk, (remainder_size - contents_size) | PREV_INUSE);
remainder_size = contents_size;
}
/* split out elements */
for (i = 0; ; ++i) {
marray[i] = chunk2mem(p);
if (i != n_elements-1) {
if (element_size != 0)
size = element_size;
else
size = request2size(sizes[i]);
remainder_size -= size;
set_head(p, size | PREV_INUSE);
p = chunk_at_offset(p, size);
}
else { /* the final element absorbs any overallocation slop */
set_head(p, remainder_size | PREV_INUSE);
break;
}
}
#if DEBUG
if (marray != chunks) {
/* final element must have exactly exhausted chunk */
if (element_size != 0)
assert(remainder_size == element_size);
else
assert(remainder_size == request2size(sizes[i]));
check_inuse_chunk(mem2chunk(marray));
}
for (i = 0; i != n_elements; ++i)
check_inuse_chunk(mem2chunk(marray[i]));
#endif
return marray;
}
/*
------------------------------ pvalloc ------------------------------
*/
#if __STD_C
Void_t* pVALLOc(size_t bytes)
#else
Void_t* pVALLOc(bytes) size_t bytes;
#endif
{
mstate av = get_malloc_state();
size_t pagesz;
/* Ensure initialization */
if (av->max_fast == 0) malloc_consolidate(av);
pagesz = av->pagesize;
return mEMALIGn(pagesz, (bytes + pagesz - 1) & ~(pagesz - 1));
}
/*
------------------------------ malloc_trim ------------------------------
*/
#if __STD_C
int mTRIm(size_t pad)
#else
int mTRIm(pad) size_t pad;
#endif
{
mstate av = get_malloc_state();
/* Ensure initialization/consolidation */
malloc_consolidate(av);
#ifndef MORECORE_CANNOT_TRIM
return sYSTRIm(pad, av);
#else
return 0;
#endif
}
/*
------------------------- malloc_usable_size -------------------------
*/
#if __STD_C
size_t mUSABLe(Void_t* mem)
#else
size_t mUSABLe(mem) Void_t* mem;
#endif
{
mchunkptr p;
if (mem != 0) {
p = mem2chunk(mem);
if (chunk_is_mmapped(p))
return chunksize(p) - 2*SIZE_SZ;
else if (inuse(p))
return chunksize(p) - SIZE_SZ;
}
return 0;
}
/*
------------------------------ mallinfo ------------------------------
*/
struct mallinfo mALLINFo()
{
mstate av = get_malloc_state();
struct mallinfo mi;
int i;
mbinptr b;
mchunkptr p;
INTERNAL_SIZE_T avail;
INTERNAL_SIZE_T fastavail;
int nblocks;
int nfastblocks;
/* Ensure initialization */
if (av->top == 0) malloc_consolidate(av);
check_malloc_state();
/* Account for top */
avail = chunksize(av->top);
nblocks = 1; /* top always exists */
/* traverse fastbins */
nfastblocks = 0;
fastavail = 0;
for (i = 0; i < NFASTBINS; ++i) {
for (p = av->fastbins[i]; p != 0; p = p->fd) {
++nfastblocks;
fastavail += chunksize(p);
}
}
avail += fastavail;
/* traverse regular bins */
for (i = 1; i < NBINS; ++i) {
b = bin_at(av, i);
for (p = last(b); p != b; p = p->bk) {
++nblocks;
avail += chunksize(p);
}
}
mi.smblks = nfastblocks;
mi.ordblks = nblocks;
mi.fordblks = avail;
mi.uordblks = av->sbrked_mem - avail;
mi.arena = av->sbrked_mem;
mi.hblks = av->n_mmaps;
mi.hblkhd = av->mmapped_mem;
mi.fsmblks = fastavail;
mi.keepcost = chunksize(av->top);
mi.usmblks = av->max_total_mem;
return mi;
}
/*
------------------------------ malloc_stats ------------------------------
*/
void mSTATs()
{
struct mallinfo mi = mALLINFo();
#ifdef WIN32
{
CHUNK_SIZE_T free, reserved, committed;
vminfo (&free, &reserved, &committed);
fprintf(stderr, "free bytes = %10lun",
free);
fprintf(stderr, "reserved bytes = %10lun",
reserved);
fprintf(stderr, "committed bytes = %10lun",
committed);
}
#endif
fprintf(stderr, "max system bytes = %10lun",
(CHUNK_SIZE_T)(mi.usmblks));
fprintf(stderr, "system bytes = %10lun",
(CHUNK_SIZE_T)(mi.arena + mi.hblkhd));
fprintf(stderr, "in use bytes = %10lun",
(CHUNK_SIZE_T)(mi.uordblks + mi.hblkhd));
#ifdef WIN32
{
CHUNK_SIZE_T kernel, user;
if (cpuinfo (TRUE, &kernel, &user)) {
fprintf(stderr, "kernel ms = %10lun",
kernel);
fprintf(stderr, "user ms = %10lun",
user);
}
}
#endif
}
/*
------------------------------ mallopt ------------------------------
*/
#if __STD_C
int mALLOPt(int param_number, int value)
#else
int mALLOPt(param_number, value) int param_number; int value;
#endif
{
mstate av = get_malloc_state();
/* Ensure initialization/consolidation */
malloc_consolidate(av);
switch(param_number) {
case M_MXFAST:
if (value >= 0 && value <= MAX_FAST_SIZE) {
set_max_fast(av, value);
return 1;
}
else
return 0;
case M_TRIM_THRESHOLD:
av->trim_threshold = value;
return 1;
case M_TOP_PAD:
av->top_pad = value;
return 1;
case M_MMAP_THRESHOLD:
av->mmap_threshold = value;
return 1;
case M_MMAP_MAX:
#if !HAVE_MMAP
if (value != 0)
return 0;
#endif
av->n_mmaps_max = value;
return 1;
default:
return 0;
}
}
#endif
/*
-------------------- Alternative MORECORE functions --------------------
*/
/*
General Requirements for MORECORE.
The MORECORE function must have the following properties:
If MORECORE_CONTIGUOUS is false:
* MORECORE must allocate in multiples of pagesize. It will
only be called with arguments that are multiples of pagesize.
* MORECORE(0) must return an address that is at least
MALLOC_ALIGNMENT aligned. (Page-aligning always suffices.)
else (i.e. If MORECORE_CONTIGUOUS is true):
* Consecutive calls to MORECORE with positive arguments
return increasing addresses, indicating that space has been
contiguously extended.
* MORECORE need not allocate in multiples of pagesize.
Calls to MORECORE need not have args of multiples of pagesize.
* MORECORE need not page-align.
In either case:
* MORECORE may allocate more memory than requested. (Or even less,
but this will generally result in a malloc failure.)
* MORECORE must not allocate memory when given argument zero, but
instead return one past the end address of memory from previous
nonzero call. This malloc does NOT call MORECORE(0)
until at least one call with positive arguments is made, so
the initial value returned is not important.
* Even though consecutive calls to MORECORE need not return contiguous
addresses, it must be OK for malloc'ed chunks to span multiple
regions in those cases where they do happen to be contiguous.
* MORECORE need not handle negative arguments -- it may instead
just return MORECORE_FAILURE when given negative arguments.
Negative arguments are always multiples of pagesize. MORECORE
must not misinterpret negative args as large positive unsigned
args. You can suppress all such calls from even occurring by defining
MORECORE_CANNOT_TRIM,
There is some variation across systems about the type of the
argument to sbrk/MORECORE. If size_t is unsigned, then it cannot
actually be size_t, because sbrk supports negative args, so it is
normally the signed type of the same width as size_t (sometimes
declared as "intptr_t", and sometimes "ptrdiff_t"). It doesn't much
matter though. Internally, we use "long" as arguments, which should
work across all reasonable possibilities.
Additionally, if MORECORE ever returns failure for a positive
request, and HAVE_MMAP is true, then mmap is used as a noncontiguous
system allocator. This is a useful backup strategy for systems with
holes in address spaces -- in this case sbrk cannot contiguously
expand the heap, but mmap may be able to map noncontiguous space.
If you'd like mmap to ALWAYS be used, you can define MORECORE to be
a function that always returns MORECORE_FAILURE.
Malloc only has limited ability to detect failures of MORECORE
to supply contiguous space when it says it can. In particular,
multithreaded programs that do not use locks may result in
rece conditions across calls to MORECORE that result in gaps
that cannot be detected as such, and subsequent corruption.
If you are using this malloc with something other than sbrk (or its
emulation) to supply memory regions, you probably want to set
MORECORE_CONTIGUOUS as false. As an example, here is a custom
allocator kindly contributed for pre-OSX macOS. It uses virtually
but not necessarily physically contiguous non-paged memory (locked
in, present and won't get swapped out). You can use it by
uncommenting this section, adding some #includes, and setting up the
appropriate defines above:
#define MORECORE osMoreCore
#define MORECORE_CONTIGUOUS 0
There is also a shutdown routine that should somehow be called for
cleanup upon program exit.
#define MAX_POOL_ENTRIES 100
#define MINIMUM_MORECORE_SIZE (64 * 1024)
static int next_os_pool;
void *our_os_pools[MAX_POOL_ENTRIES];
void *osMoreCore(int size)
{
void *ptr = 0;
static void *sbrk_top = 0;
if (size > 0)
{
if (size < MINIMUM_MORECORE_SIZE)
size = MINIMUM_MORECORE_SIZE;
if (CurrentExecutionLevel() == kTaskLevel)
ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
if (ptr == 0)
{
return (void *) MORECORE_FAILURE;
}
// save ptrs so they can be freed during cleanup
our_os_pools[next_os_pool] = ptr;
next_os_pool++;
ptr = (void *) ((((CHUNK_SIZE_T) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
sbrk_top = (char *) ptr + size;
return ptr;
}
else if (size < 0)
{
// we don't currently support shrink behavior
return (void *) MORECORE_FAILURE;
}
else
{
return sbrk_top;
}
}
// cleanup any allocated memory pools
// called as last thing before shutting down driver
void osCleanupMem(void)
{
void **ptr;
for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
if (*ptr)
{
PoolDeallocate(*ptr);
*ptr = 0;
}
}
*/
/*
--------------------------------------------------------------
Emulation of sbrk for win32.
Donated by J. Walter <Walter@GeNeSys-e.de>.
For additional information about this code, and malloc on Win32, see
http://www.genesys-e.de/jwalter/
*/
#ifdef WIN32
#ifdef _DEBUG
/* #define TRACE */
#endif
/* Support for USE_MALLOC_LOCK */
#ifdef USE_MALLOC_LOCK
/* Wait for spin lock */
static int slwait (int *sl) {
while (InterlockedCompareExchange ((void **) sl, (void *) 1, (void *) 0) != 0)
Sleep (0);
return 0;
}
/* Release spin lock */
static int slrelease (int *sl) {
InterlockedExchange (sl, 0);
return 0;
}
#ifdef NEEDED
/* Spin lock for emulation code */
static int g_sl;
#endif
#endif /* USE_MALLOC_LOCK */
/* getpagesize for windows */
static long getpagesize (void) {
static long g_pagesize = 0;
if (! g_pagesize) {
SYSTEM_INFO system_info;
GetSystemInfo (&system_info);
g_pagesize = system_info.dwPageSize;
}
return g_pagesize;
}
static long getregionsize (void) {
static long g_regionsize = 0;
if (! g_regionsize) {
SYSTEM_INFO system_info;
GetSystemInfo (&system_info);
g_regionsize = system_info.dwAllocationGranularity;
}
return g_regionsize;
}
/* A region list entry */
typedef struct _region_list_entry {
void *top_allocated;
void *top_committed;
void *top_reserved;
long reserve_size;
struct _region_list_entry *previous;
} region_list_entry;
/* Allocate and link a region entry in the region list */
static int region_list_append (region_list_entry **last, void *base_reserved, long reserve_size) {
region_list_entry *next = HeapAlloc (GetProcessHeap (), 0, sizeof (region_list_entry));
if (! next)
return FALSE;
next->top_allocated = (char *) base_reserved;
next->top_committed = (char *) base_reserved;
next->top_reserved = (char *) base_reserved + reserve_size;
next->reserve_size = reserve_size;
next->previous = *last;
*last = next;
return TRUE;
}
/* Free and unlink the last region entry from the region list */
static int region_list_remove (region_list_entry **last) {
region_list_entry *previous = (*last)->previous;
if (! HeapFree (GetProcessHeap (), sizeof (region_list_entry), *last))
return FALSE;
*last = previous;
return TRUE;
}
#define CEIL(size,to) (((size)+(to)-1)&~((to)-1))
#define FLOOR(size,to) ((size)&~((to)-1))
#define SBRK_SCALE 0
/* #define SBRK_SCALE 1 */
/* #define SBRK_SCALE 2 */
/* #define SBRK_SCALE 4 */
/* sbrk for windows */
static void *sbrk (long size) {
static long g_pagesize, g_my_pagesize;
static long g_regionsize, g_my_regionsize;
static region_list_entry *g_last;
void *result = (void *) MORECORE_FAILURE;
#ifdef TRACE
printf ("sbrk %dn", size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Wait for spin lock */
slwait (&g_sl);
#endif
/* First time initialization */
if (! g_pagesize) {
g_pagesize = getpagesize ();
g_my_pagesize = g_pagesize << SBRK_SCALE;
}
if (! g_regionsize) {
g_regionsize = getregionsize ();
g_my_regionsize = g_regionsize << SBRK_SCALE;
}
if (! g_last) {
if (! region_list_append (&g_last, 0, 0))
goto sbrk_exit;
}
/* Assert invariants */
assert (g_last);
assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated &&
g_last->top_allocated <= g_last->top_committed);
assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed &&
g_last->top_committed <= g_last->top_reserved &&
(unsigned) g_last->top_committed % g_pagesize == 0);
assert ((unsigned) g_last->top_reserved % g_regionsize == 0);
assert ((unsigned) g_last->reserve_size % g_regionsize == 0);
/* Allocation requested? */
if (size >= 0) {
/* Allocation size is the requested size */
long allocate_size = size;
/* Compute the size to commit */
long to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
/* Do we reach the commit limit? */
if (to_commit > 0) {
/* Round size to commit */
long commit_size = CEIL (to_commit, g_my_pagesize);
/* Compute the size to reserve */
long to_reserve = (char *) g_last->top_committed + commit_size - (char *) g_last->top_reserved;
/* Do we reach the reserve limit? */
if (to_reserve > 0) {
/* Compute the remaining size to commit in the current region */
long remaining_commit_size = (char *) g_last->top_reserved - (char *) g_last->top_committed;
if (remaining_commit_size > 0) {
/* Assert preconditions */
assert ((unsigned) g_last->top_committed % g_pagesize == 0);
assert (0 < remaining_commit_size && remaining_commit_size % g_pagesize == 0); {
/* Commit this */
void *base_committed = VirtualAlloc (g_last->top_committed, remaining_commit_size,
MEM_COMMIT, PAGE_READWRITE);
/* Check returned pointer for consistency */
if (base_committed != g_last->top_committed)
goto sbrk_exit;
/* Assert postconditions */
assert ((unsigned) base_committed % g_pagesize == 0);
#ifdef TRACE
printf ("Commit %p %dn", base_committed, remaining_commit_size);
#endif
/* Adjust the regions commit top */
g_last->top_committed = (char *) base_committed + remaining_commit_size;
}
} {
/* Now we are going to search and reserve. */
int contiguous = -1;
int found = FALSE;
MEMORY_BASIC_INFORMATION memory_info;
void *base_reserved;
long reserve_size;
do {
/* Assume contiguous memory */
contiguous = TRUE;
/* Round size to reserve */
reserve_size = CEIL (to_reserve, g_my_regionsize);
/* Start with the current region's top */
memory_info.BaseAddress = g_last->top_reserved;
/* Assert preconditions */
assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
assert (0 < reserve_size && reserve_size % g_regionsize == 0);
while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) {
/* Assert postconditions */
assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
#ifdef TRACE
printf ("Query %p %d %sn", memory_info.BaseAddress, memory_info.RegionSize,
memory_info.State == MEM_FREE ? "FREE":
(memory_info.State == MEM_RESERVE ? "RESERVED":
(memory_info.State == MEM_COMMIT ? "COMMITTED": "?")));
#endif
/* Region is free, well aligned and big enough: we are done */
if (memory_info.State == MEM_FREE &&
(unsigned) memory_info.BaseAddress % g_regionsize == 0 &&
memory_info.RegionSize >= (unsigned) reserve_size) {
found = TRUE;
break;
}
/* From now on we can't get contiguous memory! */
contiguous = FALSE;
/* Recompute size to reserve */
reserve_size = CEIL (allocate_size, g_my_regionsize);
memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize;
/* Assert preconditions */
assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
assert (0 < reserve_size && reserve_size % g_regionsize == 0);
}
/* Search failed? */
if (! found)
goto sbrk_exit;
/* Assert preconditions */
assert ((unsigned) memory_info.BaseAddress % g_regionsize == 0);
assert (0 < reserve_size && reserve_size % g_regionsize == 0);
/* Try to reserve this */
base_reserved = VirtualAlloc (memory_info.BaseAddress, reserve_size,
MEM_RESERVE, PAGE_NOACCESS);
if (! base_reserved) {
int rc = GetLastError ();
if (rc != ERROR_INVALID_ADDRESS)
goto sbrk_exit;
}
/* A null pointer signals (hopefully) a race condition with another thread. */
/* In this case, we try again. */
} while (! base_reserved);
/* Check returned pointer for consistency */
if (memory_info.BaseAddress && base_reserved != memory_info.BaseAddress)
goto sbrk_exit;
/* Assert postconditions */
assert ((unsigned) base_reserved % g_regionsize == 0);
#ifdef TRACE
printf ("Reserve %p %dn", base_reserved, reserve_size);
#endif
/* Did we get contiguous memory? */
if (contiguous) {
long start_size = (char *) g_last->top_committed - (char *) g_last->top_allocated;
/* Adjust allocation size */
allocate_size -= start_size;
/* Adjust the regions allocation top */
g_last->top_allocated = g_last->top_committed;
/* Recompute the size to commit */
to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
/* Round size to commit */
commit_size = CEIL (to_commit, g_my_pagesize);
}
/* Append the new region to the list */
if (! region_list_append (&g_last, base_reserved, reserve_size))
goto sbrk_exit;
/* Didn't we get contiguous memory? */
if (! contiguous) {
/* Recompute the size to commit */
to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
/* Round size to commit */
commit_size = CEIL (to_commit, g_my_pagesize);
}
}
}
/* Assert preconditions */
assert ((unsigned) g_last->top_committed % g_pagesize == 0);
assert (0 < commit_size && commit_size % g_pagesize == 0); {
/* Commit this */
void *base_committed = VirtualAlloc (g_last->top_committed, commit_size,
MEM_COMMIT, PAGE_READWRITE);
/* Check returned pointer for consistency */
if (base_committed != g_last->top_committed)
goto sbrk_exit;
/* Assert postconditions */
assert ((unsigned) base_committed % g_pagesize == 0);
#ifdef TRACE
printf ("Commit %p %dn", base_committed, commit_size);
#endif
/* Adjust the regions commit top */
g_last->top_committed = (char *) base_committed + commit_size;
}
}
/* Adjust the regions allocation top */
g_last->top_allocated = (char *) g_last->top_allocated + allocate_size;
result = (char *) g_last->top_allocated - size;
/* Deallocation requested? */
} else if (size < 0) {
long deallocate_size = - size;
/* As long as we have a region to release */
while ((char *) g_last->top_allocated - deallocate_size < (char *) g_last->top_reserved - g_last->reserve_size) {
/* Get the size to release */
long release_size = g_last->reserve_size;
/* Get the base address */
void *base_reserved = (char *) g_last->top_reserved - release_size;
/* Assert preconditions */
assert ((unsigned) base_reserved % g_regionsize == 0);
assert (0 < release_size && release_size % g_regionsize == 0); {
/* Release this */
int rc = VirtualFree (base_reserved, 0,
MEM_RELEASE);
/* Check returned code for consistency */
if (! rc)
goto sbrk_exit;
#ifdef TRACE
printf ("Release %p %dn", base_reserved, release_size);
#endif
}
/* Adjust deallocation size */
deallocate_size -= (char *) g_last->top_allocated - (char *) base_reserved;
/* Remove the old region from the list */
if (! region_list_remove (&g_last))
goto sbrk_exit;
} {
/* Compute the size to decommit */
long to_decommit = (char *) g_last->top_committed - ((char *) g_last->top_allocated - deallocate_size);
if (to_decommit >= g_my_pagesize) {
/* Compute the size to decommit */
long decommit_size = FLOOR (to_decommit, g_my_pagesize);
/* Compute the base address */
void *base_committed = (char *) g_last->top_committed - decommit_size;
/* Assert preconditions */
assert ((unsigned) base_committed % g_pagesize == 0);
assert (0 < decommit_size && decommit_size % g_pagesize == 0); {
/* Decommit this */
int rc = VirtualFree ((char *) base_committed, decommit_size,
MEM_DECOMMIT);
/* Check returned code for consistency */
if (! rc)
goto sbrk_exit;
#ifdef TRACE
printf ("Decommit %p %dn", base_committed, decommit_size);
#endif
}
/* Adjust deallocation size and regions commit and allocate top */
deallocate_size -= (char *) g_last->top_allocated - (char *) base_committed;
g_last->top_committed = base_committed;
g_last->top_allocated = base_committed;
}
}
/* Adjust regions allocate top */
g_last->top_allocated = (char *) g_last->top_allocated - deallocate_size;
/* Check for underflow */
if ((char *) g_last->top_reserved - g_last->reserve_size > (char *) g_last->top_allocated ||
g_last->top_allocated > g_last->top_committed) {
/* Adjust regions allocate top */
g_last->top_allocated = (char *) g_last->top_reserved - g_last->reserve_size;
goto sbrk_exit;
}
result = g_last->top_allocated;
}
/* Assert invariants */
assert (g_last);
assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated &&
g_last->top_allocated <= g_last->top_committed);
assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed &&
g_last->top_committed <= g_last->top_reserved &&
(unsigned) g_last->top_committed % g_pagesize == 0);
assert ((unsigned) g_last->top_reserved % g_regionsize == 0);
assert ((unsigned) g_last->reserve_size % g_regionsize == 0);
sbrk_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Release spin lock */
slrelease (&g_sl);
#endif
return result;
}
/* mmap for windows */
static void *mmap (void *ptr, long size, long prot, long type, long handle, long arg) {
static long g_pagesize;
static long g_regionsize;
#ifdef TRACE
printf ("mmap %dn", size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Wait for spin lock */
slwait (&g_sl);
#endif
/* First time initialization */
if (! g_pagesize)
g_pagesize = getpagesize ();
if (! g_regionsize)
g_regionsize = getregionsize ();
/* Assert preconditions */
assert ((unsigned) ptr % g_regionsize == 0);
assert (size % g_pagesize == 0);
/* Allocate this */
ptr = VirtualAlloc (ptr, size,
MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, PAGE_READWRITE);
if (! ptr) {
ptr = (void *) MORECORE_FAILURE;
goto mmap_exit;
}
/* Assert postconditions */
assert ((unsigned) ptr % g_regionsize == 0);
#ifdef TRACE
printf ("Commit %p %dn", ptr, size);
#endif
mmap_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Release spin lock */
slrelease (&g_sl);
#endif
return ptr;
}
/* munmap for windows */
static long munmap (void *ptr, long size) {
static long g_pagesize;
static long g_regionsize;
int rc = MUNMAP_FAILURE;
#ifdef TRACE
printf ("munmap %p %dn", ptr, size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Wait for spin lock */
slwait (&g_sl);
#endif
/* First time initialization */
if (! g_pagesize)
g_pagesize = getpagesize ();
if (! g_regionsize)
g_regionsize = getregionsize ();
/* Assert preconditions */
assert ((unsigned) ptr % g_regionsize == 0);
assert (size % g_pagesize == 0);
/* Free this */
if (! VirtualFree (ptr, 0,
MEM_RELEASE))
goto munmap_exit;
rc = 0;
#ifdef TRACE
printf ("Release %p %dn", ptr, size);
#endif
munmap_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
/* Release spin lock */
slrelease (&g_sl);
#endif
return rc;
}
static void vminfo (CHUNK_SIZE_T *free, CHUNK_SIZE_T *reserved, CHUNK_SIZE_T *committed) {
MEMORY_BASIC_INFORMATION memory_info;
memory_info.BaseAddress = 0;
*free = *reserved = *committed = 0;
while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) {
switch (memory_info.State) {
case MEM_FREE:
*free += memory_info.RegionSize;
break;
case MEM_RESERVE:
*reserved += memory_info.RegionSize;
break;
case MEM_COMMIT:
*committed += memory_info.RegionSize;
break;
}
memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize;
}
}
static int cpuinfo (int whole, CHUNK_SIZE_T *kernel, CHUNK_SIZE_T *user) {
if (whole) {
__int64 creation64, exit64, kernel64, user64;
int rc = GetProcessTimes (GetCurrentProcess (),
(FILETIME *) &creation64,
(FILETIME *) &exit64,
(FILETIME *) &kernel64,
(FILETIME *) &user64);
if (! rc) {
*kernel = 0;
*user = 0;
return FALSE;
}
*kernel = (CHUNK_SIZE_T) (kernel64 / 10000);
*user = (CHUNK_SIZE_T) (user64 / 10000);
return TRUE;
} else {
__int64 creation64, exit64, kernel64, user64;
int rc = GetThreadTimes (GetCurrentThread (),
(FILETIME *) &creation64,
(FILETIME *) &exit64,
(FILETIME *) &kernel64,
(FILETIME *) &user64);
if (! rc) {
*kernel = 0;
*user = 0;
return FALSE;
}
*kernel = (CHUNK_SIZE_T) (kernel64 / 10000);
*user = (CHUNK_SIZE_T) (user64 / 10000);
return TRUE;
}
}
#endif /* WIN32 */
/* ------------------------------------------------------------
History:
V2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
* Fix malloc_state bitmap array misdeclaration
V2.7.1 Thu Jul 25 10:58:03 2002 Doug Lea (dl at gee)
* Allow tuning of FIRST_SORTED_BIN_SIZE
* Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
* Better detection and support for non-contiguousness of MORECORE.
Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
* Bypass most of malloc if no frees. Thanks To Emery Berger.
* Fix freeing of old top non-contiguous chunk im sysmalloc.
* Raised default trim and map thresholds to 256K.
* Fix mmap-related #defines. Thanks to Lubos Lunak.
* Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
* Branch-free bin calculation
* Default trim and mmap thresholds now 256K.
V2.7.0 Sun Mar 11 14:14:06 2001 Doug Lea (dl at gee)
* Introduce independent_comalloc and independent_calloc.
Thanks to Michael Pachos for motivation and help.
* Make optional .h file available
* Allow > 2GB requests on 32bit systems.
* new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
and Anonymous.
* Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
helping test this.)
* memalign: check alignment arg
* realloc: don't try to shift chunks backwards, since this
leads to more fragmentation in some programs and doesn't
seem to help in any others.
* Collect all cases in malloc requiring system memory into sYSMALLOc
* Use mmap as backup to sbrk
* Place all internal state in malloc_state
* Introduce fastbins (although similar to 2.5.1)
* Many minor tunings and cosmetic improvements
* Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
* Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
* Include errno.h to support default failure action.
V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
* return null for negative arguments
* Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
* Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
(e.g. WIN32 platforms)
* Cleanup header file inclusion for WIN32 platforms
* Cleanup code to avoid Microsoft Visual C++ compiler complaints
* Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
memory allocation routines
* Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
* Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
usage of 'assert' in non-WIN32 code
* Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
avoid infinite loop
* Always call 'fREe()' rather than 'free()'
V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
* Fixed ordering problem with boundary-stamping
V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
* Added pvalloc, as recommended by H.J. Liu
* Added 64bit pointer support mainly from Wolfram Gloger
* Added anonymously donated WIN32 sbrk emulation
* Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
* malloc_extend_top: fix mask error that caused wastage after
foreign sbrks
* Add linux mremap support code from HJ Liu
V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
* Integrated most documentation with the code.
* Add support for mmap, with help from
Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
* Use last_remainder in more cases.
* Pack bins using idea from colin@nyx10.cs.du.edu
* Use ordered bins instead of best-fit threshhold
* Eliminate block-local decls to simplify tracing and debugging.
* Support another case of realloc via move into top
* Fix error occuring when initial sbrk_base not word-aligned.
* Rely on page size for units instead of SBRK_UNIT to
avoid surprises about sbrk alignment conventions.
* Add mallinfo, mallopt. Thanks to Raymond Nijssen
(raymond@es.ele.tue.nl) for the suggestion.
* Add `pad' argument to malloc_trim and top_pad mallopt parameter.
* More precautions for cases where other routines call sbrk,
courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
* Added macros etc., allowing use in linux libc from
H.J. Lu (hjl@gnu.ai.mit.edu)
* Inverted this history list
V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
* Re-tuned and fixed to behave more nicely with V2.6.0 changes.
* Removed all preallocation code since under current scheme
the work required to undo bad preallocations exceeds
the work saved in good cases for most test programs.
* No longer use return list or unconsolidated bins since
no scheme using them consistently outperforms those that don't
given above changes.
* Use best fit for very large chunks to prevent some worst-cases.
* Added some support for debugging
V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
* Removed footers when chunks are in use. Thanks to
Paul Wilson (wilson@cs.texas.edu) for the suggestion.
V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
* Added malloc_trim, with help from Wolfram Gloger
(wmglo@Dent.MED.Uni-Muenchen.DE).
V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
* realloc: try to expand in both directions
* malloc: swap order of clean-bin strategy;
* realloc: only conditionally expand backwards
* Try not to scavenge used bins
* Use bin counts as a guide to preallocation
* Occasionally bin return list chunks in first scan
* Add a few optimizations from colin@nyx10.cs.du.edu
V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
* faster bin computation & slightly different binning
* merged all consolidations to one part of malloc proper
(eliminating old malloc_find_space & malloc_clean_bin)
* Scan 2 returns chunks (not just 1)
* Propagate failure in realloc if malloc returns 0
* Add stuff to allow compilation on non-ANSI compilers
from kpv@research.att.com
V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
* removed potential for odd address access in prev_chunk
* removed dependency on getpagesize.h
* misc cosmetics and a bit more internal documentation
* anticosmetics: mangled names in macros to evade debugger strangeness
* tested on sparc, hp-700, dec-mips, rs6000
with gcc & native cc (hp, dec only) allowing
Detlefs & Zorn comparison study (in SIGPLAN Notices.)
Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
* Based loosely on libg++-1.2X malloc. (It retains some of the overall
structure of old version, but most details differ.)
*/
#endif /* _USE_OWN_MALLOC */