lsearch(3) is just lfind(3) + append. If we write it that way we
shrink lsearch.c. The third function, linear_base(), is just added
complexity. The indirection buys us nothing.
I don't think we need to keep the historical comment, either.
lsearch(3) is pure computation, it does not set errno: The End.
The spec defines no errors, either.
libc housekeeping:
- lfind becomes PROTO_NORMAL because we're now using it internally.
- lfind then needs DEF_WEAK because it is not ISO C.
Unsure if I'm missing other libc housekeeping.
If not, ok?
Index: stdlib/lsearch.c
===================================================================
RCS file: /cvs/src/lib/libc/stdlib/lsearch.c,v
retrieving revision 1.6
diff -u -p -r1.6 lsearch.c
--- stdlib/lsearch.c 7 Dec 2021 04:01:45 -0000 1.6
+++ stdlib/lsearch.c 7 Dec 2021 04:32:34 -0000
@@ -37,53 +37,34 @@
#include <search.h>
typedef int (*cmp_fn_t)(const void *, const void *);
-static void *linear_base(const void *, const void *, size_t *, size_t,
- cmp_fn_t, int);
void *
lsearch(const void *key, void *base, size_t *nelp, size_t width,
cmp_fn_t compar)
{
+ void *element = lfind(key, base, nelp, width, compar);
- return(linear_base(key, base, nelp, width, compar, 1));
+ /*
+ * Use memmove(3) to ensure the key is copied cleanly into the
+ * array, even if the key overlaps with the end of the array.
+ */
+ if (element == NULL) {
+ element = memmove((char *)base + *nelp * width, key, width);
+ *nelp += 1;
+ }
+ return element;
}
void *
lfind(const void *key, const void *base, size_t *nelp, size_t width,
cmp_fn_t compar)
{
- return(linear_base(key, base, nelp, width, compar, 0));
-}
-
-static void *
-linear_base(const void *key, const void *base, size_t *nelp, size_t width,
- cmp_fn_t compar, int add_flag)
-{
const char *element, *end;
end = (const char *)base + *nelp * width;
for (element = base; element < end; element += width)
if (!compar(key, element)) /* key found */
return((void *)element);
-
- if (!add_flag) /* key not found */
- return(NULL);
-
- /*
- * The UNIX System User's Manual, 1986 edition claims that
- * a NULL pointer is returned by lsearch with errno set
- * appropriately, if there is not enough room in the table
- * to add a new item. This can't be done as none of these
- * routines have any method of determining the size of the
- * table. This comment isn't in the 1986-87 System V
- * manual.
- */
- ++*nelp;
-
- /*
- * Use memmove(3) to ensure the key is copied cleanly into the
- * array, even if the key overlaps with the end of the array.
- */
- memmove((void *)end, key, width);
- return((void *)end);
+ return NULL;
}
+DEF_WEAK(lfind);
Index: hidden/search.h
===================================================================
RCS file: /cvs/src/lib/libc/hidden/search.h,v
retrieving revision 1.1
diff -u -p -r1.1 search.h
--- hidden/search.h 4 Oct 2015 08:36:57 -0000 1.1
+++ hidden/search.h 7 Dec 2021 04:32:34 -0000
@@ -24,7 +24,7 @@ PROTO_DEPRECATED(hcreate);
PROTO_DEPRECATED(hdestroy);
PROTO_DEPRECATED(hsearch);
PROTO_DEPRECATED(insque);
-PROTO_DEPRECATED(lfind);
+PROTO_NORMAL(lfind);
PROTO_DEPRECATED(lsearch);
PROTO_DEPRECATED(remque);
PROTO_DEPRECATED(tdelete);
