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-rw-r--r--gnu/lib/libmalloc/malloc.c622
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diff --git a/gnu/lib/libmalloc/malloc.c b/gnu/lib/libmalloc/malloc.c
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+/* Memory allocator `malloc'.
+ Copyright 1990, 1991, 1992, 1993 Free Software Foundation
+ Written May 1989 by Mike Haertel.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with this library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.
+
+ The author may be reached (Email) at the address mike@ai.mit.edu,
+ or (US mail) as Mike Haertel c/o Free Software Foundation. */
+
+#ifndef _MALLOC_INTERNAL
+#define _MALLOC_INTERNAL
+#include <malloc.h>
+#endif
+
+/* How to really get more memory. */
+__ptr_t (*__morecore) __P ((ptrdiff_t __size)) = __default_morecore;
+
+/* Debugging hook for `malloc'. */
+__ptr_t (*__malloc_hook) __P ((size_t __size));
+
+/* Pointer to the base of the first block. */
+char *_heapbase;
+
+/* Block information table. Allocated with align/__free (not malloc/free). */
+malloc_info *_heapinfo;
+
+/* Number of info entries. */
+static size_t heapsize;
+
+/* Search index in the info table. */
+size_t _heapindex;
+
+/* Limit of valid info table indices. */
+size_t _heaplimit;
+
+/* Free lists for each fragment size. */
+struct list _fraghead[BLOCKLOG];
+
+/* Instrumentation. */
+size_t _chunks_used;
+size_t _bytes_used;
+size_t _chunks_free;
+size_t _bytes_free;
+
+/* Are you experienced? */
+int __malloc_initialized;
+
+void (*__after_morecore_hook) __P ((void));
+
+/* Aligned allocation. */
+static __ptr_t align __P ((size_t));
+static __ptr_t
+align (size)
+ size_t size;
+{
+ __ptr_t result;
+ unsigned long int adj;
+
+ result = (*__morecore) (size);
+ adj = (unsigned long int) ((unsigned long int) ((char *) result -
+ (char *) NULL)) % BLOCKSIZE;
+ if (adj != 0)
+ {
+ adj = BLOCKSIZE - adj;
+ (void) (*__morecore) (adj);
+ result = (char *) result + adj;
+ }
+
+ if (__after_morecore_hook)
+ (*__after_morecore_hook) ();
+
+ return result;
+}
+
+/* Set everything up and remember that we have. */
+static int initialize __P ((void));
+static int
+initialize ()
+{
+ heapsize = HEAP / BLOCKSIZE;
+ _heapinfo = (malloc_info *) align (heapsize * sizeof (malloc_info));
+ if (_heapinfo == NULL)
+ return 0;
+ memset (_heapinfo, 0, heapsize * sizeof (malloc_info));
+ _heapinfo[0].free.size = 0;
+ _heapinfo[0].free.next = _heapinfo[0].free.prev = 0;
+ _heapindex = 0;
+ _heapbase = (char *) _heapinfo;
+ __malloc_initialized = 1;
+ return 1;
+}
+
+/* Get neatly aligned memory, initializing or
+ growing the heap info table as necessary. */
+static __ptr_t morecore __P ((size_t));
+static __ptr_t
+morecore (size)
+ size_t size;
+{
+ __ptr_t result;
+ malloc_info *newinfo, *oldinfo;
+ size_t newsize;
+
+ result = align (size);
+ if (result == NULL)
+ return NULL;
+
+ /* Check if we need to grow the info table. */
+ if ((size_t) BLOCK ((char *) result + size) > heapsize)
+ {
+ newsize = heapsize;
+ while ((size_t) BLOCK ((char *) result + size) > newsize)
+ newsize *= 2;
+ newinfo = (malloc_info *) align (newsize * sizeof (malloc_info));
+ if (newinfo == NULL)
+ {
+ (*__morecore) (-size);
+ return NULL;
+ }
+ memset (newinfo, 0, newsize * sizeof (malloc_info));
+ memcpy (newinfo, _heapinfo, heapsize * sizeof (malloc_info));
+ oldinfo = _heapinfo;
+ newinfo[BLOCK (oldinfo)].busy.type = 0;
+ newinfo[BLOCK (oldinfo)].busy.info.size
+ = BLOCKIFY (heapsize * sizeof (malloc_info));
+ _heapinfo = newinfo;
+ _free_internal (oldinfo);
+ heapsize = newsize;
+ }
+
+ _heaplimit = BLOCK ((char *) result + size);
+ return result;
+}
+
+/* Allocate memory from the heap. */
+__ptr_t
+malloc (size)
+ size_t size;
+{
+ __ptr_t result;
+ size_t block, blocks, lastblocks, start;
+ register size_t i;
+ struct list *next;
+
+ /* ANSI C allows `malloc (0)' to either return NULL, or to return a
+ valid address you can realloc and free (though not dereference).
+
+ It turns out that some extant code (sunrpc, at least Ultrix's version)
+ expects `malloc (0)' to return non-NULL and breaks otherwise.
+ Be compatible. */
+
+#if 0
+ if (size == 0)
+ return NULL;
+#endif
+
+ if (__malloc_hook != NULL)
+ return (*__malloc_hook) (size);
+
+ if (!__malloc_initialized)
+ if (!initialize ())
+ return NULL;
+
+ if (size < sizeof (struct list))
+ size = sizeof (struct list);
+
+ /* Determine the allocation policy based on the request size. */
+ if (size <= BLOCKSIZE / 2)
+ {
+ /* Small allocation to receive a fragment of a block.
+ Determine the logarithm to base two of the fragment size. */
+ register size_t log = 1;
+ --size;
+ while ((size /= 2) != 0)
+ ++log;
+
+ /* Look in the fragment lists for a
+ free fragment of the desired size. */
+ next = _fraghead[log].next;
+ if (next != NULL)
+ {
+ /* There are free fragments of this size.
+ Pop a fragment out of the fragment list and return it.
+ Update the block's nfree and first counters. */
+ result = (__ptr_t) next;
+ next->prev->next = next->next;
+ if (next->next != NULL)
+ next->next->prev = next->prev;
+ block = BLOCK (result);
+ if (--_heapinfo[block].busy.info.frag.nfree != 0)
+ _heapinfo[block].busy.info.frag.first = (unsigned long int)
+ ((unsigned long int) ((char *) next->next - (char *) NULL)
+ % BLOCKSIZE) >> log;
+
+ /* Update the statistics. */
+ ++_chunks_used;
+ _bytes_used += 1 << log;
+ --_chunks_free;
+ _bytes_free -= 1 << log;
+ }
+ else
+ {
+ /* No free fragments of the desired size, so get a new block
+ and break it into fragments, returning the first. */
+ result = malloc (BLOCKSIZE);
+ if (result == NULL)
+ return NULL;
+
+ /* Link all fragments but the first into the free list. */
+ for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i)
+ {
+ next = (struct list *) ((char *) result + (i << log));
+ next->next = _fraghead[log].next;
+ next->prev = &_fraghead[log];
+ next->prev->next = next;
+ if (next->next != NULL)
+ next->next->prev = next;
+ }
+
+ /* Initialize the nfree and first counters for this block. */
+ block = BLOCK (result);
+ _heapinfo[block].busy.type = log;
+ _heapinfo[block].busy.info.frag.nfree = i - 1;
+ _heapinfo[block].busy.info.frag.first = i - 1;
+
+ _chunks_free += (BLOCKSIZE >> log) - 1;
+ _bytes_free += BLOCKSIZE - (1 << log);
+ _bytes_used -= BLOCKSIZE - (1 << log);
+ }
+ }
+ else
+ {
+ /* Large allocation to receive one or more blocks.
+ Search the free list in a circle starting at the last place visited.
+ If we loop completely around without finding a large enough
+ space we will have to get more memory from the system. */
+ blocks = BLOCKIFY (size);
+ start = block = _heapindex;
+ while (_heapinfo[block].free.size < blocks)
+ {
+ block = _heapinfo[block].free.next;
+ if (block == start)
+ {
+ /* Need to get more from the system. Check to see if
+ the new core will be contiguous with the final free
+ block; if so we don't need to get as much. */
+ block = _heapinfo[0].free.prev;
+ lastblocks = _heapinfo[block].free.size;
+ if (_heaplimit != 0 && block + lastblocks == _heaplimit &&
+ (*__morecore) (0) == ADDRESS (block + lastblocks) &&
+ (morecore ((blocks - lastblocks) * BLOCKSIZE)) != NULL)
+ {
+ _heapinfo[block].free.size = blocks;
+ _bytes_free += (blocks - lastblocks) * BLOCKSIZE;
+ continue;
+ }
+ result = morecore (blocks * BLOCKSIZE);
+ if (result == NULL)
+ return NULL;
+ block = BLOCK (result);
+ _heapinfo[block].busy.type = 0;
+ _heapinfo[block].busy.info.size = blocks;
+ ++_chunks_used;
+ _bytes_used += blocks * BLOCKSIZE;
+ return result;
+ }
+ }
+
+ /* At this point we have found a suitable free list entry.
+ Figure out how to remove what we need from the list. */
+ result = ADDRESS (block);
+ if (_heapinfo[block].free.size > blocks)
+ {
+ /* The block we found has a bit left over,
+ so relink the tail end back into the free list. */
+ _heapinfo[block + blocks].free.size
+ = _heapinfo[block].free.size - blocks;
+ _heapinfo[block + blocks].free.next
+ = _heapinfo[block].free.next;
+ _heapinfo[block + blocks].free.prev
+ = _heapinfo[block].free.prev;
+ _heapinfo[_heapinfo[block].free.prev].free.next
+ = _heapinfo[_heapinfo[block].free.next].free.prev
+ = _heapindex = block + blocks;
+ }
+ else
+ {
+ /* The block exactly matches our requirements,
+ so just remove it from the list. */
+ _heapinfo[_heapinfo[block].free.next].free.prev
+ = _heapinfo[block].free.prev;
+ _heapinfo[_heapinfo[block].free.prev].free.next
+ = _heapindex = _heapinfo[block].free.next;
+ --_chunks_free;
+ }
+
+ _heapinfo[block].busy.type = 0;
+ _heapinfo[block].busy.info.size = blocks;
+ ++_chunks_used;
+ _bytes_used += blocks * BLOCKSIZE;
+ _bytes_free -= blocks * BLOCKSIZE;
+ }
+
+ return result;
+}
+
+#define min(A, B) ((A) < (B) ? (A) : (B))
+
+/* Debugging hook for realloc. */
+__ptr_t (*__realloc_hook) __P ((__ptr_t __ptr, size_t __size));
+
+/* Resize the given region to the new size, returning a pointer
+ to the (possibly moved) region. This is optimized for speed;
+ some benchmarks seem to indicate that greater compactness is
+ achieved by unconditionally allocating and copying to a
+ new region. This module has incestuous knowledge of the
+ internals of both free and malloc. */
+__ptr_t
+realloc (ptr, size)
+ __ptr_t ptr;
+ size_t size;
+{
+ __ptr_t result;
+ int type;
+ size_t block, blocks, oldlimit;
+
+ if (size == 0)
+ {
+ free (ptr);
+ return malloc (0);
+ }
+ else if (ptr == NULL)
+ return malloc (size);
+
+ if (__realloc_hook != NULL)
+ return (*__realloc_hook) (ptr, size);
+
+ block = BLOCK (ptr);
+
+ type = _heapinfo[block].busy.type;
+ switch (type)
+ {
+ case 0:
+ /* Maybe reallocate a large block to a small fragment. */
+ if (size <= BLOCKSIZE / 2)
+ {
+ result = malloc (size);
+ if (result != NULL)
+ {
+ memcpy (result, ptr, size);
+ free (ptr);
+ return result;
+ }
+ }
+
+ /* The new size is a large allocation as well;
+ see if we can hold it in place. */
+ blocks = BLOCKIFY (size);
+ if (blocks < _heapinfo[block].busy.info.size)
+ {
+ /* The new size is smaller; return
+ excess memory to the free list. */
+ _heapinfo[block + blocks].busy.type = 0;
+ _heapinfo[block + blocks].busy.info.size
+ = _heapinfo[block].busy.info.size - blocks;
+ _heapinfo[block].busy.info.size = blocks;
+ free (ADDRESS (block + blocks));
+ result = ptr;
+ }
+ else if (blocks == _heapinfo[block].busy.info.size)
+ /* No size change necessary. */
+ result = ptr;
+ else
+ {
+ /* Won't fit, so allocate a new region that will.
+ Free the old region first in case there is sufficient
+ adjacent free space to grow without moving. */
+ blocks = _heapinfo[block].busy.info.size;
+ /* Prevent free from actually returning memory to the system. */
+ oldlimit = _heaplimit;
+ _heaplimit = 0;
+ free (ptr);
+ _heaplimit = oldlimit;
+ result = malloc (size);
+ if (result == NULL)
+ {
+ /* Now we're really in trouble. We have to unfree
+ the thing we just freed. Unfortunately it might
+ have been coalesced with its neighbors. */
+ if (_heapindex == block)
+ (void) malloc (blocks * BLOCKSIZE);
+ else
+ {
+ __ptr_t previous = malloc ((block - _heapindex) * BLOCKSIZE);
+ (void) malloc (blocks * BLOCKSIZE);
+ free (previous);
+ }
+ return NULL;
+ }
+ if (ptr != result)
+ memmove (result, ptr, blocks * BLOCKSIZE);
+ }
+ break;
+
+ default:
+ /* Old size is a fragment; type is logarithm
+ to base two of the fragment size. */
+ if (size > (size_t) (1 << (type - 1)) && size <= (size_t) (1 << type))
+ /* The new size is the same kind of fragment. */
+ result = ptr;
+ else
+ {
+ /* The new size is different; allocate a new space,
+ and copy the lesser of the new size and the old. */
+ result = malloc (size);
+ if (result == NULL)
+ return NULL;
+ memcpy (result, ptr, min (size, (size_t) 1 << type));
+ free (ptr);
+ }
+ break;
+ }
+
+ return result;
+}
+
+/* Debugging hook for free. */
+void (*__free_hook) __P ((__ptr_t __ptr));
+
+/* List of blocks allocated by memalign. */
+struct alignlist *_aligned_blocks = NULL;
+
+/* Return memory to the heap.
+ Like `free' but don't call a __free_hook if there is one. */
+void
+_free_internal (ptr)
+ __ptr_t ptr;
+{
+ int type;
+ size_t block, blocks;
+ register size_t i;
+ struct list *prev, *next;
+
+ block = BLOCK (ptr);
+
+ type = _heapinfo[block].busy.type;
+ switch (type)
+ {
+ case 0:
+ /* Get as many statistics as early as we can. */
+ --_chunks_used;
+ _bytes_used -= _heapinfo[block].busy.info.size * BLOCKSIZE;
+ _bytes_free += _heapinfo[block].busy.info.size * BLOCKSIZE;
+
+ /* Find the free cluster previous to this one in the free list.
+ Start searching at the last block referenced; this may benefit
+ programs with locality of allocation. */
+ i = _heapindex;
+ if (i > block)
+ while (i > block)
+ i = _heapinfo[i].free.prev;
+ else
+ {
+ do
+ i = _heapinfo[i].free.next;
+ while (i > 0 && i < block);
+ i = _heapinfo[i].free.prev;
+ }
+
+ /* Determine how to link this block into the free list. */
+ if (block == i + _heapinfo[i].free.size)
+ {
+ /* Coalesce this block with its predecessor. */
+ _heapinfo[i].free.size += _heapinfo[block].busy.info.size;
+ block = i;
+ }
+ else
+ {
+ /* Really link this block back into the free list. */
+ _heapinfo[block].free.size = _heapinfo[block].busy.info.size;
+ _heapinfo[block].free.next = _heapinfo[i].free.next;
+ _heapinfo[block].free.prev = i;
+ _heapinfo[i].free.next = block;
+ _heapinfo[_heapinfo[block].free.next].free.prev = block;
+ ++_chunks_free;
+ }
+
+ /* Now that the block is linked in, see if we can coalesce it
+ with its successor (by deleting its successor from the list
+ and adding in its size). */
+ if (block + _heapinfo[block].free.size == _heapinfo[block].free.next)
+ {
+ _heapinfo[block].free.size
+ += _heapinfo[_heapinfo[block].free.next].free.size;
+ _heapinfo[block].free.next
+ = _heapinfo[_heapinfo[block].free.next].free.next;
+ _heapinfo[_heapinfo[block].free.next].free.prev = block;
+ --_chunks_free;
+ }
+
+ /* Now see if we can return stuff to the system. */
+ blocks = _heapinfo[block].free.size;
+ if (blocks >= FINAL_FREE_BLOCKS && block + blocks == _heaplimit
+ && (*__morecore) (0) == ADDRESS (block + blocks))
+ {
+ register size_t bytes = blocks * BLOCKSIZE;
+ _heaplimit -= blocks;
+ (*__morecore) (-bytes);
+ _heapinfo[_heapinfo[block].free.prev].free.next
+ = _heapinfo[block].free.next;
+ _heapinfo[_heapinfo[block].free.next].free.prev
+ = _heapinfo[block].free.prev;
+ block = _heapinfo[block].free.prev;
+ --_chunks_free;
+ _bytes_free -= bytes;
+ }
+
+ /* Set the next search to begin at this block. */
+ _heapindex = block;
+ break;
+
+ default:
+ /* Do some of the statistics. */
+ --_chunks_used;
+ _bytes_used -= 1 << type;
+ ++_chunks_free;
+ _bytes_free += 1 << type;
+
+ /* Get the address of the first free fragment in this block. */
+ prev = (struct list *) ((char *) ADDRESS (block) +
+ (_heapinfo[block].busy.info.frag.first << type));
+
+ if (_heapinfo[block].busy.info.frag.nfree == (BLOCKSIZE >> type) - 1)
+ {
+ /* If all fragments of this block are free, remove them
+ from the fragment list and free the whole block. */
+ next = prev;
+ for (i = 1; i < (size_t) (BLOCKSIZE >> type); ++i)
+ next = next->next;
+ prev->prev->next = next;
+ if (next != NULL)
+ next->prev = prev->prev;
+ _heapinfo[block].busy.type = 0;
+ _heapinfo[block].busy.info.size = 1;
+
+ /* Keep the statistics accurate. */
+ ++_chunks_used;
+ _bytes_used += BLOCKSIZE;
+ _chunks_free -= BLOCKSIZE >> type;
+ _bytes_free -= BLOCKSIZE;
+
+ free (ADDRESS (block));
+ }
+ else if (_heapinfo[block].busy.info.frag.nfree != 0)
+ {
+ /* If some fragments of this block are free, link this
+ fragment into the fragment list after the first free
+ fragment of this block. */
+ next = (struct list *) ptr;
+ next->next = prev->next;
+ next->prev = prev;
+ prev->next = next;
+ if (next->next != NULL)
+ next->next->prev = next;
+ ++_heapinfo[block].busy.info.frag.nfree;
+ }
+ else
+ {
+ /* No fragments of this block are free, so link this
+ fragment into the fragment list and announce that
+ it is the first free fragment of this block. */
+ prev = (struct list *) ptr;
+ _heapinfo[block].busy.info.frag.nfree = 1;
+ _heapinfo[block].busy.info.frag.first = (unsigned long int)
+ ((unsigned long int) ((char *) ptr - (char *) NULL)
+ % BLOCKSIZE >> type);
+ prev->next = _fraghead[type].next;
+ prev->prev = &_fraghead[type];
+ prev->prev->next = prev;
+ if (prev->next != NULL)
+ prev->next->prev = prev;
+ }
+ break;
+ }
+}
+
+/* Return memory to the heap. */
+void
+free (ptr)
+ __ptr_t ptr;
+{
+ register struct alignlist *l;
+
+ if (ptr == NULL)
+ return;
+
+ for (l = _aligned_blocks; l != NULL; l = l->next)
+ if (l->aligned == ptr)
+ {
+ l->aligned = NULL; /* Mark the slot in the list as free. */
+ ptr = l->exact;
+ break;
+ }
+
+ if (__free_hook != NULL)
+ (*__free_hook) (ptr);
+ else
+ _free_internal (ptr);
+}
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