--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/dynarr.c	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,232 @@
+/* Simple 'n' stupid dynamic-array module.
+   Copyright (C) 1993 Sun Microsystems, Inc.
+
+This file is part of XEmacs.
+
+XEmacs is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+XEmacs 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 General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with:  Not in FSF. */
+
+/* Written by Ben Wing, December 1993. */
+
+/*
+
+A "dynamic array" is a contiguous array of fixed-size elements where there
+is no upper limit (except available memory) on the number of elements in the
+array.  Because the elements are maintained contiguously, space is used
+efficiently (no per-element pointers necessary) and random access to a
+particular element is in constant time.  At any one point, the block of memory
+that holds the array has an upper limit; if this limit is exceeded, the
+memory is realloc()ed into a new array that is twice as big.  Assuming that
+the time to grow the array is on the order of the new size of the array
+block, this scheme has a provably constant amortized time (i.e. average
+time over all additions).
+
+When you add elements or retrieve elements, pointers are used.  Note that
+the element itself (of whatever size it is), and not the pointer to it,
+is stored in the array; thus you do not have to allocate any heap memory
+on your own.  Also, returned pointers are only guaranteed to be valid
+until the next operation that changes the length of the array.
+
+This is a container object.  Declare a dynamic array of a specific type
+as follows:
+
+struct mytype_dynarr
+{
+  Dynarr_declare (mytype);
+};
+
+Use the following functions/macros:
+
+   void *Dynarr_new(type)
+      [MACRO] Create a new dynamic-array object, with each element of the
+      specified type.  The return value is a void * and must be cast to the
+      proper dynamic array type.
+
+   Dynarr_add(d, el)
+      [MACRO] Add an element to the end of a dynamic array.  EL is a pointer
+      to the element; the element itself is stored in the array, however.
+      No function call is performed unless the array needs to be resized.
+
+   Dynarr_add_many(d, base, len)
+      [MACRO] Add LEN elements to the end of the dynamic array.  The elements
+      should be contiguous in memory, starting at BASE.
+
+   Dynarr_insert_many_at_start(d, base, len)
+      [MACRO] Append LEN elements to the beginning of the dynamic array.
+      The elements should be contiguous in memory, starting at BASE.
+
+   Dynarr_insert_many(d, base, len, start)
+      Insert LEN elements to the dynamic arrary starting at position
+      START.  The elements should be contiguous in memory, starting at BASE.
+
+   int Dynarr_length(d)
+      [MACRO] Return the number of elements currently in a dynamic array.
+
+   type Dynarr_at(d, i)
+      [MACRO] Return the element at the specified index (no bounds checking
+      done on the index).  The element itself is returned, not a pointer
+      to it.
+
+   type *Dynarr_atp(d, i)
+      [MACRO] Return a pointer to the element at the specified index (no
+      bounds checking done on the index).  The pointer may not be valid
+      after an element is added to or removed from the array.
+
+   Dynarr_reset(d)
+      [MACRO] Reset the length of a dynamic array to 0.
+
+   Dynarr_free(d)
+      Destroy a dynamic array and the memory allocated to it.
+
+Use the following global variable:
+
+   Dynarr_min_size
+      Minimum allowable size for a dynamic array when it is resized.  The
+      default is 32 and does not normally need to be changed.
+
+*/
+
+#include <config.h>
+#include "lisp.h"
+
+int Dynarr_min_size = 1;
+
+void *
+Dynarr_newf (int elsize)
+{
+  Dynarr *d = (Dynarr *) xmalloc (sizeof (Dynarr));
+
+  memset (d, 0, sizeof (*d));
+  d->elsize = elsize;
+
+  return d;
+}
+
+void
+Dynarr_resize (void *d, int size)
+{
+  int newsize;
+  double multiplier;
+  Dynarr *dy = (Dynarr *) d;
+
+  if (dy->max <= 8)
+    multiplier = 2;
+  else
+    multiplier = 1.5;
+
+  for (newsize = dy->max; newsize < size;)
+    newsize = max (Dynarr_min_size, multiplier * newsize);
+
+  /* Don't do anything if the array is already big enough. */
+  if (newsize > dy->max)
+    {
+      dy->base = xrealloc (dy->base, newsize*dy->elsize);
+      dy->max = newsize;
+    }
+}
+
+/* Add a number of contiguous elements to the array starting at START. */
+void
+Dynarr_insert_many (void *d, CONST void *el, int len, int start)
+{
+  Dynarr *dy = (Dynarr *) d;
+
+  Dynarr_resize (dy, dy->cur+len);
+  /* Silently adjust start to be valid. */
+  if (start > dy->cur)
+    start = dy->cur;
+  else if (start < 0)
+    start = 0;
+
+  if (start != dy->cur)
+    {
+      memmove ((char *) dy->base + (start + len)*dy->elsize,
+	       (char *) dy->base + start*dy->elsize,
+	       (dy->cur - start)*dy->elsize);
+    }
+  memcpy ((char *) dy->base + start*dy->elsize, el, len*dy->elsize);
+  dy->cur += len;
+
+  if (dy->cur > dy->largest)
+    dy->largest = dy->cur;
+}
+
+void
+Dynarr_delete_many (void *d, int start, int len)
+{
+  Dynarr *dy = (Dynarr *) d;
+
+  assert (start >= 0 && len >= 0 && start + len <= dy->cur);
+  memmove ((char *) dy->base + start*dy->elsize,
+	   (char *) dy->base + (start + len)*dy->elsize,
+	   (dy->cur - start - len)*dy->elsize);
+  dy->cur -= len;
+}
+
+void
+Dynarr_free (void *d)
+{
+  Dynarr *dy = (Dynarr *) d;
+
+  if (dy->base)
+    xfree (dy->base);
+  xfree (dy);
+}
+
+#ifdef MEMORY_USAGE_STATS
+
+/* Return memory usage for Dynarr D.  The returned value is the total
+   amount of bytes actually being used for the Dynarr, including all
+   overhead.  The extra amount of space in the Dynarr that is
+   allocated beyond what was requested is returned in DYNARR_OVERHEAD
+   in STATS.  The extra amount of space that malloc() allocates beyond
+   what was requested of it is returned in MALLOC_OVERHEAD in STATS.
+   See the comment above the definition of this structure. */
+
+int
+Dynarr_memory_usage (void *d, struct overhead_stats *stats)
+{
+  int total = 0;
+  Dynarr *dy = (Dynarr *) d;
+
+  /* We have to be a bit tricky here because not all of the
+     memory that malloc() will claim as "requested" was actually
+     requested. */
+
+  if (dy->base)
+    {
+      int malloc_used = malloced_storage_size (dy->base,
+					       dy->elsize * dy->max, 0);
+      /* #### This may or may not be correct.  Some Dynarrs would
+	 prefer that we use dy->cur instead of dy->largest here. */
+      int was_requested = dy->elsize * dy->largest;
+      int dynarr_overhead = dy->elsize * (dy->max - dy->largest);
+
+      total += malloc_used;
+      stats->was_requested += was_requested;
+      stats->dynarr_overhead += dynarr_overhead;
+      /* And the remainder must be malloc overhead. */
+      stats->malloc_overhead +=
+	malloc_used - was_requested - dynarr_overhead;
+    }
+
+  total += malloced_storage_size (d, sizeof (*dy), stats);
+
+  return total;
+}
+
+#endif