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diff src/dynarr.c @ 4844:91b3d00e717f

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Various cleanups for Dynarr code, from Unicode-internal ws dynarr.c: Add comment explaining Dynarr_largest() use. dynarr.c: In Dynarr_insert_many(), don't call Dynarr_resize() unless we actually need to resize, and note that an assert() that we are inserting at or below the current end could be wrong if code wants to access stuff between `len' and `largest'. dynarr.c: Don't just Dynarr_resize() to the right size; instead use Dynarr_reset() then Dynarr_add_many(), so that the 'len' and 'largest' and such get set properly. dynarr.c, faces.c, gutter.c, lisp.h, lread.c, lrecord.h, redisplay-output.c, redisplay.c: Rename Dynarr member 'cur' to 'len' since it's the length of the dynarr, not really a pointer to a "current insertion point". Use type_checking_assert() instead of just assert() in some places. Add additional assertions (Dynarr_verify*()) to check that we're being given positions within range. Use them in Dynarr_at, Dynarr_atp, etc. New Dynarr_atp_allow_end() for retrieving a pointer to a position that might be the element past the last one. New Dynarr_past_lastp() to retrieve a pointer to the position past the last one, using Dynarr_atp_allow_end(). Change code appropriately to use it. Rename Dynarr_end() to Dynarr_lastp() (pointer to the last element) for clarity, and change code appropriately to use it. Change code appropriately to use Dynarr_begin(). Rewrite Dynarr_add_many(). New version can accept a NULL pointer to mean "reserve space but don't put anything in it". Used by stack_like_malloc().
author Ben Wing <ben@xemacs.org>
date Wed, 13 Jan 2010 04:07:42 -0600
parents 229bd619740a
children 19a72041c5ed
line wrap: on
line diff
--- a/src/dynarr.c	Wed Jan 13 03:01:43 2010 -0600
+++ b/src/dynarr.c	Wed Jan 13 04:07:42 2010 -0600
@@ -1,6 +1,6 @@
 /* Support for dynamic arrays.
    Copyright (C) 1993 Sun Microsystems, Inc.
-   Copyright (C) 2002, 2003, 2004 Ben Wing.
+   Copyright (C) 2002, 2003, 2004, 2005 Ben Wing.
 
 This file is part of XEmacs.
 
@@ -98,7 +98,8 @@
 
    int Dynarr_largest(d)
       [MACRO] Return the maximum value that Dynarr_length(d) would
-      ever have returned.
+      ever have returned.  This is used esp. in the redisplay code,
+      which reuses dynarrs for performance reasons.
 
    type Dynarr_at(d, i)
       [MACRO] Return the element at the specified index (no bounds checking
@@ -217,30 +218,33 @@
 {
   Dynarr *dy = (Dynarr *) Dynarr_verify (d);
   
-  Dynarr_resize (dy, dy->cur+len);
+  if (dy->len + len > dy->max)
+    Dynarr_resize (dy, dy->len + len);
 #if 0
   /* WTF? We should be catching these problems. */
   /* Silently adjust start to be valid. */
-  if (start > dy->cur)
-    start = dy->cur;
+  if (start > dy->len)
+    start = dy->len;
   else if (start < 0)
     start = 0;
 #else
-  assert (start >= 0 && start <= dy->cur);
+  /* #### This could conceivably be wrong, if code wants to access stuff
+     between len and largest. */
+  type_checking_assert (start >= 0 && start <= dy->len);
 #endif
 
-  if (start != dy->cur)
+  if (start != dy->len)
     {
       memmove ((char *) dy->base + (start + len)*dy->elsize,
 	       (char *) dy->base + start*dy->elsize,
-	       (dy->cur - start)*dy->elsize);
+	       (dy->len - start)*dy->elsize);
     }
   if (el)
     memcpy ((char *) dy->base + start*dy->elsize, el, len*dy->elsize);
-  dy->cur += len;
+  dy->len += len;
 
-  if (dy->cur > dy->largest)
-    dy->largest = dy->cur;
+  if (dy->len > dy->largest)
+    dy->largest = dy->len;
 }
 
 void
@@ -248,11 +252,11 @@
 {
   Dynarr *dy = (Dynarr *) Dynarr_verify (d);
 
-  assert (start >= 0 && len >= 0 && start + len <= dy->cur);
+  type_checking_assert (start >= 0 && len >= 0 && start + len <= dy->len);
   memmove ((char *) dy->base + start*dy->elsize,
 	   (char *) dy->base + (start + len)*dy->elsize,
-	   (dy->cur - start - len)*dy->elsize);
-  dy->cur -= len;
+	   (dy->len - start - len)*dy->elsize);
+  dy->len -= len;
 }
 
 void
@@ -304,7 +308,7 @@
       Bytecount 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. */
+	 prefer that we use dy->len instead of dy->largest here. */
       Bytecount was_requested = dy->elsize * dy->largest;
       Bytecount dynarr_overhead = dy->elsize * (dy->max - dy->largest);
 
@@ -353,7 +357,8 @@
   else
     this_one = Dynarr_new (char);
   Dynarr_add (stack_like_in_use_list, this_one);
-  Dynarr_resize (this_one, size);
+  Dynarr_reset (this_one);
+  Dynarr_add_many (this_one, 0, size);
   return Dynarr_atp (this_one, 0);
 }