/* -*-c-*-
*
- * $Id: darray.c,v 1.1 1999/10/22 22:37:26 mdw Exp $
+ * $Id: darray.c,v 1.3 1999/10/29 22:59:22 mdw Exp $
*
* Dynamically growing dense arrays
*
/*----- Revision history --------------------------------------------------*
*
* $Log: darray.c,v $
+ * Revision 1.3 1999/10/29 22:59:22 mdw
+ * New array adjustment macros for unsigned arguments.
+ *
+ * Revision 1.2 1999/10/28 22:05:28 mdw
+ * Modify and debug allocation routines.
+ *
* Revision 1.1 1999/10/22 22:37:26 mdw
* New dynamic array implementation replaces `dynarray.h'.
*
/*----- Magic numbers -----------------------------------------------------*/
-#define DA_INITSZ 64 /* Default size for new array */
+#define DA_INITSZ 16 /* Default size for new array */
#define DA_SLOTS 8 /* Number of preshifted slots */
/*----- Main code ---------------------------------------------------------*/
return (q);
}
- /* --- Reallocate the array --- */
+ /* --- Reallocate the array --- *
+ *
+ * If the offset isn't changing, it's sensible to use @realloc@ if
+ * available. Otherwise the overhead of copying all the data twice
+ * probably isn't worth it.
+ */
- nsz = v ? b->sz + b->off : DA_INITSZ;
+ nsz = v ? b->sz + b->off : (DA_INITSZ >> 1);
do nsz <<= 1; while (nsz < rq);
- q = xmalloc(nsz * sz);
- q += slots * sz;
- memcpy(q, p, b->len * sz);
- if (p)
- free(p - b->off * sz);
+ if (p && slots == b->off) {
+ q = xrealloc(p - b->off * sz, nsz * sz);
+ q += slots * sz;
+ } else {
+ q = xmalloc(nsz * sz);
+ q += slots * sz;
+ if (p) {
+ memcpy(q, p, b->len * sz);
+ free(p - b->off * sz);
+ }
+ }
b->off = slots;
b->sz = nsz - slots;
b->unshift = b->push = 0;
return (q);
}
- /* --- Reallocate the array --- */
+ /* --- Reallocate the array --- *
+ *
+ * The neat @realloc@ code doesn't need to be here: the offset changes
+ * almost all the time -- that's the whole point of this routine!
+ */
- nsz = v ? b->sz + b->off : DA_INITSZ;
+ nsz = v ? b->sz + b->off : (DA_INITSZ >> 1);
do nsz <<= 1; while (nsz < rq);
q = xmalloc(nsz * sz);
q += (nsz - slots) * sz;
- memcpy(q, p, b->len * sz);
- if (p)
+ if (p) {
+ memcpy(q, p, b->len * sz);
free(p - b->off * sz);
+ }
b->off = nsz - slots;
b->sz = slots;
b->unshift = b->push = 0;