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-rw-r--r--mmalloc/mmalloc.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/mmalloc/mmalloc.c b/mmalloc/mmalloc.c
new file mode 100644
index 0000000..885a8ea
--- /dev/null
+++ b/mmalloc/mmalloc.c
@@ -0,0 +1,327 @@
+/* Memory allocator `malloc'.
+ Copyright 1990, 1991, 1992 Free Software Foundation
+
+ Written May 1989 by Mike Haertel.
+ Heavily modified Mar 1992 by Fred Fish for mmap'c version.
+
+The GNU C 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.
+
+The GNU C 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 the GNU C 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. */
+
+#include "mmalloc.h"
+
+/* Prototypes for local functions */
+
+static int initialize PARAMS ((struct mdesc *));
+static PTR morecore PARAMS ((struct mdesc *, size_t));
+static PTR align PARAMS ((struct mdesc *, size_t));
+
+/* Aligned allocation. */
+
+static PTR
+align (mdp, size)
+ struct mdesc *mdp;
+ size_t size;
+{
+ PTR result;
+ unsigned long int adj;
+
+ result = mdp -> morecore (mdp, size);
+ adj = RESIDUAL (result, BLOCKSIZE);
+ if (adj != 0)
+ {
+ adj = BLOCKSIZE - adj;
+ (void) mdp -> morecore (mdp, adj);
+ result = (char *) result + adj;
+ }
+ return (result);
+}
+
+/* Set everything up and remember that we have. */
+
+static int
+initialize (mdp)
+ struct mdesc *mdp;
+{
+ mdp -> heapsize = HEAP / BLOCKSIZE;
+ mdp -> heapinfo = (malloc_info *)
+ align (mdp, mdp -> heapsize * sizeof (malloc_info));
+ if (mdp -> heapinfo == NULL)
+ {
+ return (0);
+ }
+ memset ((PTR)mdp -> heapinfo, 0, mdp -> heapsize * sizeof (malloc_info));
+ mdp -> heapinfo[0].free.size = 0;
+ mdp -> heapinfo[0].free.next = mdp -> heapinfo[0].free.prev = 0;
+ mdp -> heapindex = 0;
+ mdp -> heapbase = (char *) mdp -> heapinfo;
+ mdp -> flags |= MMALLOC_INITIALIZED;
+ return (1);
+}
+
+/* Get neatly aligned memory, initializing or
+ growing the heap info table as necessary. */
+
+static PTR
+morecore (mdp, size)
+ struct mdesc *mdp;
+ size_t size;
+{
+ PTR result;
+ malloc_info *newinfo, *oldinfo;
+ size_t newsize;
+
+ result = align (mdp, size);
+ if (result == NULL)
+ {
+ return (NULL);
+ }
+
+ /* Check if we need to grow the info table. */
+ if ((size_t) BLOCK ((char *) result + size) > mdp -> heapsize)
+ {
+ newsize = mdp -> heapsize;
+ while ((size_t) BLOCK ((char *) result + size) > newsize)
+ {
+ newsize *= 2;
+ }
+ newinfo = (malloc_info *) align (mdp, newsize * sizeof (malloc_info));
+ if (newinfo == NULL)
+ {
+ mdp -> morecore (mdp, -size);
+ return (NULL);
+ }
+ memset ((PTR)newinfo, 0, newsize * sizeof (malloc_info));
+ memcpy ((PTR)newinfo, (PTR)mdp -> heapinfo,
+ mdp -> heapsize * sizeof (malloc_info));
+ oldinfo = mdp -> heapinfo;
+ newinfo[BLOCK (oldinfo)].busy.type = 0;
+ newinfo[BLOCK (oldinfo)].busy.info.size
+ = BLOCKIFY (mdp -> heapsize * sizeof (malloc_info));
+ mdp -> heapinfo = newinfo;
+ __mmalloc_free (mdp, (PTR)oldinfo);
+ mdp -> heapsize = newsize;
+ }
+
+ mdp -> heaplimit = BLOCK ((char *) result + size);
+ return (result);
+}
+
+/* Allocate memory from the heap. */
+
+PTR
+mmalloc (md, size)
+ PTR md;
+ size_t size;
+{
+ struct mdesc *mdp;
+ PTR result;
+ size_t block, blocks, lastblocks, start;
+ register size_t i;
+ struct list *next;
+ register size_t log;
+
+ if (size == 0)
+ {
+ return (NULL);
+ }
+
+ mdp = MD_TO_MDP (md);
+
+ if (mdp -> mmalloc_hook != NULL)
+ {
+ return ((*mdp -> mmalloc_hook) (md, size));
+ }
+
+ if (!(mdp -> flags & MMALLOC_INITIALIZED))
+ {
+ if (!initialize (mdp))
+ {
+ 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. */
+ log = 1;
+ --size;
+ while ((size /= 2) != 0)
+ {
+ ++log;
+ }
+
+ /* Look in the fragment lists for a
+ free fragment of the desired size. */
+ next = mdp -> 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) next;
+ next -> prev -> next = next -> next;
+ if (next -> next != NULL)
+ {
+ next -> next -> prev = next -> prev;
+ }
+ block = BLOCK (result);
+ if (--mdp -> heapinfo[block].busy.info.frag.nfree != 0)
+ {
+ mdp -> heapinfo[block].busy.info.frag.first =
+ RESIDUAL (next -> next, BLOCKSIZE) >> log;
+ }
+
+ /* Update the statistics. */
+ mdp -> heapstats.chunks_used++;
+ mdp -> heapstats.bytes_used += 1 << log;
+ mdp -> heapstats.chunks_free--;
+ mdp -> heapstats.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 = mmalloc (md, 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 = mdp -> fraghead[log].next;
+ next -> prev = &mdp -> 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);
+ mdp -> heapinfo[block].busy.type = log;
+ mdp -> heapinfo[block].busy.info.frag.nfree = i - 1;
+ mdp -> heapinfo[block].busy.info.frag.first = i - 1;
+
+ mdp -> heapstats.chunks_free += (BLOCKSIZE >> log) - 1;
+ mdp -> heapstats.bytes_free += BLOCKSIZE - (1 << log);
+ mdp -> heapstats.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 = MALLOC_SEARCH_START;
+ while (mdp -> heapinfo[block].free.size < blocks)
+ {
+ block = mdp -> 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 = mdp -> heapinfo[0].free.prev;
+ lastblocks = mdp -> heapinfo[block].free.size;
+ if (mdp -> heaplimit != 0 &&
+ block + lastblocks == mdp -> heaplimit &&
+ mdp -> morecore (mdp, 0) == ADDRESS(block + lastblocks) &&
+ (morecore (mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL)
+ {
+ mdp -> heapinfo[block].free.size = blocks;
+ mdp -> heapstats.bytes_free +=
+ (blocks - lastblocks) * BLOCKSIZE;
+ continue;
+ }
+ result = morecore(mdp, blocks * BLOCKSIZE);
+ if (result == NULL)
+ {
+ return (NULL);
+ }
+ block = BLOCK (result);
+ mdp -> heapinfo[block].busy.type = 0;
+ mdp -> heapinfo[block].busy.info.size = blocks;
+ mdp -> heapstats.chunks_used++;
+ mdp -> heapstats.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 (mdp -> heapinfo[block].free.size > blocks)
+ {
+ /* The block we found has a bit left over,
+ so relink the tail end back into the free list. */
+ mdp -> heapinfo[block + blocks].free.size
+ = mdp -> heapinfo[block].free.size - blocks;
+ mdp -> heapinfo[block + blocks].free.next
+ = mdp -> heapinfo[block].free.next;
+ mdp -> heapinfo[block + blocks].free.prev
+ = mdp -> heapinfo[block].free.prev;
+ mdp -> heapinfo[mdp -> heapinfo[block].free.prev].free.next
+ = mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev
+ = mdp -> heapindex = block + blocks;
+ }
+ else
+ {
+ /* The block exactly matches our requirements,
+ so just remove it from the list. */
+ mdp -> heapinfo[mdp -> heapinfo[block].free.next].free.prev
+ = mdp -> heapinfo[block].free.prev;
+ mdp -> heapinfo[mdp -> heapinfo[block].free.prev].free.next
+ = mdp -> heapindex = mdp -> heapinfo[block].free.next;
+ mdp -> heapstats.chunks_free--;
+ }
+
+ mdp -> heapinfo[block].busy.type = 0;
+ mdp -> heapinfo[block].busy.info.size = blocks;
+ mdp -> heapstats.chunks_used++;
+ mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
+ mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
+ }
+
+ return (result);
+}
+
+/* When using this package, provide a version of malloc/realloc/free built
+ on top of it, so that if we use the default sbrk() region we will not
+ collide with another malloc package trying to do the same thing, if
+ the application contains any "hidden" calls to malloc/realloc/free (such
+ as inside a system library). */
+
+PTR
+malloc (size)
+ size_t size;
+{
+ return (mmalloc ((void *) NULL, size));
+}
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