removed the limitation of the next field

modules/src/alloc/alloc.3

@@ -67,8 +67,7 @@ All these routines use \fImalloc\fR and \fIrealloc\fR.
 \fIFree\fR can be used on pointers returned by these routines.
 .PP
 \fISt_alloc\fR and \fIst_free\fR provide a mechanism for maintaining free lists
-of structures, whose first field is a pointer called \fBnext\fR.
+of structures.
-This field is used to chain free structures together.
 \fISt_alloc\fR takes three parameters: \fIphead\fR is a pointer to a field
 containing the head of the free list, \fIsize\fR contains the size of the
 structures, and \fIcount\fR indicates how many new structures must be allocated
@@ -93,3 +92,12 @@ malloc(3)
 call a routine \fINo_Mem\fR if there is no memory available. This routine
 is not supposed to return. A default one, that
 gives an error message and stops execution, is provided.
+.SH BUGS
+The
+.I st_alloc
+mechanism only works for structures that are large enough to contain one
+pointer.
+Also,
+.I st_free
+actually is a macro, and references its arguments more than once, so they
+better not have side-effects.

modules/src/alloc/alloc.h

@@ -20,9 +20,17 @@ extern char *malloc(), *realloc();
 
 /*	S T R U C T U R E - S T O R A G E  D E F I N I T I O N S	*/
 
+typedef struct _ALLOC_ {
+	struct _ALLOC_ *_A_next;
+} *_PALLOC_;
+
+#define	_A_st_free(ptr, phead, size)	(((_PALLOC_)ptr)->_A_next = \
+						(_PALLOC_)(*phead), \
+					 *((_PALLOC_ *)phead) = \
+						(_PALLOC_) ptr)
 #ifndef	BOTCH_FREE
-#define	st_free(ptr, phead, size)	(ptr->next = *phead, *phead = ptr)
+#define st_free(ptr, phead, size)	_A_st_free(ptr, phead, size)
 #else	def BOTCH_FREE
 #define	st_free(ptr, phead, size)	(botch((char *)(ptr), size), \
-						ptr->next = *phead, *phead = ptr)
+						_A_st_free(ptr, phead, size))
 #endif	BOTCH_FREE

modules/src/alloc/st_alloc.c

@@ -4,18 +4,12 @@
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
 /*	st_alloc - get a structure from a free list. If no structures left,
-		create new ones. The structures for which this works are
+		create new ones.
-		supposed to have as their first tag the string "next", which
-		should be a pointer type.
 		The counterpart, st_free, is a macro, defined in alloc.h
 */
 
 #include	"alloc.h"
 
-struct xxx	{
-	char *next;
-};
-
 char *
 st_alloc(phead, size, count)
 	char **phead;
@@ -28,15 +22,15 @@ st_alloc(phead, size, count)
 	if (*phead == 0)	{
 
 		p = Malloc(size * count);
-		((struct xxx *) p)->next = 0;
+		((_PALLOC_) p)->_A_next = 0;
 		while (--count) {
 			p += size;
-			((struct xxx *) p)->next = p - size;
+			((_PALLOC_) p)->_A_next = p - size;
 		}
 		*phead = p;
 	}
 	else	p = *phead;
-	*phead = ((struct xxx *)p)->next;
+	*phead = ((_PALLOC_)p)->_A_next;
 	retval = p;
 	if (size >= sizeof(long)) {
 		q = (long *) p;

modules/src/alloc/std_alloc.c

@@ -4,18 +4,12 @@
  * See the copyright notice in the ACK home directory, in the file "Copyright".
  */
 /*	st_alloc - get a structure from a free list. If no structures left,
-		create new ones. The structures for which this works are
+		create new ones.
-		supposed to have as their first tag the string "next", which
-		should be a pointer type.
 		The counterpart, st_free, is a macro, defined in alloc.h
 */
 
 #include	"alloc.h"
 
-struct xxx	{
-	char *next;
-};
-
 char *
 std_alloc(phead, size, count, pcnt)
 	char **phead;
@@ -28,15 +22,15 @@ std_alloc(phead, size, count, pcnt)
 
 		p = Malloc(size * count);
 		*pcnt += count;
-		((struct xxx *) p)->next = 0;
+		((_PALLOC_) p)->_A_next = 0;
 		while (--count) {
 			p += size;
-			((struct xxx *) p)->next = p - size;
+			((_PALLOC_) p)->_A_next = p - size;
 		}
 		*phead = p;
 	}
 	else p = *phead;
-	*phead = ((struct xxx *) p)->next;
+	*phead = ((_PALLOC_) p)->_A_next;
 	p += size;
 	while (size--) *--p = 0;
 	return p;