add directory gnu

gnu/glibc/glibc-1.03/malloc/malloc.c

@@ -0,0 +1,309 @@
+/* Memory allocator `malloc'.
+   Copyright 1990, 1991 Free Software Foundation
+		  Written May 1989 by Mike Haertel.
+
+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. */
+
+/* IGNORE(@ */
+#include <ansidecl.h>
+#include <stddef.h>
+#include <stdlib.h>
+/* @) */
+
+#define _MALLOC_INTERNAL
+#include <malloc.h>
+
+#if	defined(__GNU_LIBRARY__) || defined(STDC_HEADERS) || defined(USG)
+#include <string.h>
+#else
+#define	memset(s, zero, n)	bzero ((s), (n))
+#define	memcpy(d, s, n)		bcopy ((s), (d), (n))
+#endif
+
+
+/* How to really get more memory.  */
+PTR EXFUN((*__morecore), (ptrdiff_t __size)) = __default_morecore;
+
+/* Debugging hook for `malloc'.  */
+PTR EXFUN((*__malloc_hook), (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;
+
+/* Aligned allocation.  */
+static PTR
+DEFUN(align, (size), size_t size)
+{
+  PTR 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;
+    }
+  return result;
+}
+
+/* Set everything up and remember that we have.  */
+static int
+DEFUN_VOID(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
+DEFUN(morecore, (size), size_t size)
+{
+  PTR 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(oldinfo);
+      heapsize = newsize;
+    }
+
+  _heaplimit = BLOCK((char *) result + size);
+  return result;
+}
+
+/* Allocate memory from the heap.  */
+PTR
+DEFUN(malloc, (size), size_t size)
+{
+  PTR result;
+  size_t block, blocks, lastblocks, start;
+  register size_t i;
+  struct list *next;
+
+  if (size == 0)
+    return NULL;
+
+  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) 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 = MALLOC_SEARCH_START;
+      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;
+}