+2004-09-02 Gary V. Vaughan <gary@gnu.org>,
+ Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
+
+ * libltdl/slist.c, libltdl/slist.h: Merge in changes from latest
+ upstream. Mostly comments, formal item boxing, a sort function,
+ and const madness reduction.
+ (slist_new): Removed.
+ (slist_box, slist_unbox, slist_sort): New.
+ (SListCompare, SListCallback): Swapped!
+ (slist_remove, slist_find): Change order of parameters for
+ orthogonality with slist_foreach. Changed all callers.
+ * libltdl/lt_dlloader.c (loader_cmp): Renamed to...
+ (loader_callback): ...this. Return boxed item.
+ (lt_dlloader_remove): Adjust to new loader_callback semantics;
+ unbox each removed item before returning.
+ Remove unused variable.
+ Remove const from name parameter, since the slist API cannot
+ guarantee userdata const-ancy for its callback functions.
+ (lt_dlloader_find): Adjust to new loader_callback semantics; need
+ to return the contents of the boxed item.
+ Remove const from name parameter, since the slist API cannot
+ guarantee userdata const-ancy for its callback functions.
+ * libltdl/lt_dlloader.h (lt_dlloader_find, lt_dlloader_remove):
+ Adjust to new constless footprint.
+ * libltdl/ltdl.c (ltdl_exit): The global `loaders' list is changed
+ by `lt_dlloader_remove' while cleaning up, so the address in local
+ variable `loader' is invalidated. Since some loaders may be
+ resident modules that cannot be unloaded (though we have none
+ yet), we must save each `next' address before calling
+ `lt_dlloader_remove'.
+ * NEWS: Updated.
+ * THANKS: Added Ralf.
+
2004-09-01 Gary V. Vaughan <gary@gnu.org>
* libltdl/lt_dlloader.c (lt_dlloader_add): Handle malloc failure
#define RETURN_SUCCESS 0
#define RETURN_FAILURE 1
-static void * loader_cmp (const SList *node, const void *userdata);
+static void * loader_callback (SList *item, void *userdata);
-/* A list of all the dlloaders we know about, each stored in the
- USERDATA field of an SList node: */
+/* A list of all the dlloaders we know about, each stored as a boxed
+ SList item: */
static SList *loaders = 0;
-/* Return NULL, unless the loader in this NODE has a matching name,
- in which case we return the vtable from matching node so that its
- address is passed back out (for possible freeing) by slist_remove. */
+
+/* Return NULL, unless the loader in this ITEM has a matching name,
+ in which case we return the matching item so that its address is
+ passed back out (for possible freeing) by slist_remove. */
static void *
-loader_cmp (const SList *node, const void *userdata)
+loader_callback (SList *item, void *userdata)
{
- const lt_dlvtable *vtable = node->userdata;
+ const lt_dlvtable *vtable = item->userdata;
const char * name = userdata;
assert (vtable);
- return streq (vtable->name, name) ? (void *) vtable : 0;
+ return streq (vtable->name, name) ? (void *) item : 0;
}
int
lt_dlloader_add (const lt_dlvtable *vtable)
{
- SList *list;
+ SList *item;
if ((vtable == 0) /* diagnose invalid vtable fields */
|| (vtable->module_open == 0)
return RETURN_FAILURE;
}
- list = slist_new (vtable);
- if (!list)
+ item = slist_box (vtable);
+ if (!item)
{
(*lt__alloc_die) ();
if (vtable->priority == LT_DLLOADER_PREPEND)
{
- loaders = slist_cons (list, loaders);
+ loaders = slist_cons (item, loaders);
}
else
{
assert (vtable->priority == LT_DLLOADER_APPEND);
- loaders = slist_concat (loaders, list);
+ loaders = slist_concat (loaders, item);
}
return RETURN_SUCCESS;
lt_dlloader
lt_dlloader_next (lt_dlloader loader)
{
- SList *node = (SList *) loader;
- return (lt_dlloader) (node ? node->next : loaders);
+ SList *item = (SList *) loader;
+ return (lt_dlloader) (item ? item->next : loaders);
}
+/* Non-destructive unboxing of a loader. */
const lt_dlvtable *
lt_dlloader_get (lt_dlloader loader)
{
- return ((SList *) loader)->userdata;
+ return loader ? ((SList *) loader)->userdata : 0;
}
+
/* Return the contents of the first item in the global loader list
with a matching NAME after removing it from that list. If there
was no match, return NULL; if there is an error, return NULL and
- set an error for lt_dlerror; in either case the loader list is
- not changed. */
+ set an error for lt_dlerror; in either case, the loader list is
+ not changed if NULL is returned. */
lt_dlvtable *
-lt_dlloader_remove (const char *name)
+lt_dlloader_remove (char *name)
{
const lt_dlvtable * vtable = lt_dlloader_find (name);
lt__handle * handle = 0;
- int errors = 0;
if (!vtable)
{
}
/* If we got this far, remove the loader from our global list. */
- return slist_remove (&loaders, name, loader_cmp);
+ return slist_unbox (slist_remove (&loaders, loader_callback, name));
}
const lt_dlvtable *
-lt_dlloader_find (const char *name)
+lt_dlloader_find (char *name)
{
- return slist_find (loaders, name, loader_cmp);
+ return lt_dlloader_get (slist_find (loaders, loader_callback, name));
}
/* slist.h -- generalised singly linked lists
Copyright (C) 2000, 2004 Free Software Foundation, Inc.
- Originally by Gary V. Vaughan <gary@gnu.org>
+ Written by Gary V. Vaughan <gary@gnu.org>
NOTE: The canonical source of this file is maintained with the
GNU Libtool package. Report bugs to bug-libtool@gnu.org.
#include "slist.h"
+static SList * slist_sort_merge (SList *left, SList *right,
+ SListCompare *compare, void *userdata);
-SList *
-slist_new (const void *userdata)
-{
- SList *node = malloc (sizeof *node);
- if (node)
- {
- node->next = 0;
- node->userdata = userdata;
- }
+/* Call DELETE repeatedly on each element of HEAD.
- return node;
-}
+ CAVEAT: If you call this when HEAD is the start of a list of boxed
+ items, you must remember that each item passed back to your
+ DELETE function will be a boxed item must be slist_unbox()ed
+ before operating on its contents.
+ e.g. void boxed_delete (void *item) { item_free (slist_unbox (item)); }
+ ...
+ slist = slist_delete (slist, boxed_delete);
+ ...
+*/
SList *
-slist_delete (SList *head, void (*delete) (void *data))
+slist_delete (SList *head, void (*delete) (void *item))
{
assert (delete);
return 0;
}
-/* Call Find repeatedly with MATCH and each element of *PHEAD, until
+/* Call FIND repeatedly with MATCHDATA and each item of *PHEAD, until
FIND returns non-NULL, or the list is exhausted. If a match is found
- the matching element is removed from *PHEAD, and the value returned
- by the matching call to FIND is returned.
+ the matching item is destructively removed from *PHEAD, and the value
+ returned by the matching call to FIND is returned.
- To avoid memory leaks, unless you already have the address of the
- stale element, you should probably return that from FIND if it makes
- a successful match. */
+ CAVEAT: To avoid memory leaks, unless you already have the address of
+ the stale item, you should probably return that from FIND if
+ it makes a successful match. Don't forget to slist_unbox()
+ every item in a boxed list before operating on its contents. */
void *
-slist_remove (SList **phead, const void *match, SListCompare *find)
+slist_remove (SList **phead, SListCallback *find, void *matchdata)
{
SList *stale = 0;
void *result = 0;
return 0;
/* Does the head of the passed list match? */
- result = (*find) (*phead, match);
+ result = (*find) (*phead, matchdata);
if (result)
{
stale = *phead;
SList *head;
for (head = *phead; head->next; head = head->next)
{
- result = (*find) (head->next, match);
+ result = (*find) (head->next, matchdata);
if (result)
{
stale = head->next;
return result;
}
+/* Call FIND repeatedly with each element of SLIST and MATCHDATA, until
+ FIND returns non-NULL, or the list is exhausted. If a match is found
+ the value returned by the matching call to FIND is returned. */
+void *
+slist_find (SList *slist, SListCallback *find, void *matchdata)
+{
+ void *result = 0;
+
+ assert (find);
+
+ for (; slist; slist = slist->next)
+ {
+ result = (*find) (slist, matchdata);
+ if (result)
+ break;
+ }
+
+ return result;
+}
+
+/* Return a single list, composed by destructively concatenating the
+ items in HEAD and TAIL. The values of HEAD and TAIL are undefined
+ after calling this function.
+
+ CAVEAT: Don't mix boxed and unboxed items in a single list.
+
+ e.g. slist1 = slist_concat (slist1, slist2); */
SList *
slist_concat (SList *head, SList *tail)
{
return head;
}
+/* Return a single list, composed by destructively appending all of
+ the items in SLIST to ITEM. The values of ITEM and SLIST are undefined
+ after calling this function.
+
+ CAVEAT: Don't mix boxed and unboxed items in a single list.
+
+ e.g. slist1 = slist_cons (slist_box (data), slist1); */
SList *
-slist_cons (SList *head, SList *tail)
+slist_cons (SList *item, SList *slist)
{
- if (!head)
+ if (!item)
{
- return tail;
+ return slist;
}
- head->next = tail;
- return head;
+ item->next = slist;
+ return item;
}
+/* Return a list starting at the second item of SLIST. */
SList *
-slist_tail (SList *head)
+slist_tail (SList *slist)
{
- return head ? head->next : 0;
+ return slist ? slist->next : 0;
}
+/* Return a list starting at the Nth item of SLIST. If SLIST is less
+ than N items long, NULL is returned. Just to be confusing, list items
+ are counted from 1, to get the 2nd element of slist:
+
+ e.g. shared_list = slist_nth (slist, 2); */
SList *
-slist_nth (SList *head, size_t n)
+slist_nth (SList *slist, size_t n)
{
- for (;n > 1 && head; n--)
- head = head->next;
+ for (;n > 1 && slist; n--)
+ slist = slist->next;
- return head;
+ return slist;
}
-/* Call FIND repeatedly with SEARCH and each element of HEAD, until
- FIND returns non-NULL, or the list is exhausted. If a match is found
- the value returned by the matching call to FIND is returned. */
+/* Return the number of items in SLIST. We start counting from 1, so
+ the length of a list with no items is 0, and so on. */
+size_t
+slist_length (SList *slist)
+{
+ size_t n;
+
+ for (n = 0; slist; ++n)
+ slist = slist->next;
+
+ return n;
+}
+
+/* Destructively reverse the order of items in SLIST. The value of SLIST
+ is undefined after calling this function.
+
+ CAVEAT: You must stare the result of this function, or you might not
+ be able to get all the items except the first one back again.
+
+ e.g. slist = slist_reverse (slist); */
+SList *
+slist_reverse (SList *slist)
+{
+ SList *result = 0;
+ SList *next;
+
+ while (slist)
+ {
+ next = slist->next;
+ slist->next = result;
+ result = slist;
+ slist = next;
+ }
+
+ return result;
+}
+
+/* Call FOREACH once for each item in SLIST, passing both the item and
+ USERDATA on each call. */
void *
-slist_find (SList *head, const void *match, SListCompare *find)
+slist_foreach (SList *slist, SListCallback *foreach, void *userdata)
{
void *result = 0;
- assert (find);
+ assert (foreach);
- for (; head; head = head->next)
+ while (slist)
{
- result = (*find) (head, match);
+ SList *next = slist->next;
+ void *result = (*foreach) (slist, userdata);
+
if (result)
break;
+
+ slist = next;
}
return result;
}
-size_t
-slist_length (SList *head)
+/* Destructively merge the items of two ordered lists LEFT and RIGHT,
+ returning a single sorted list containing the items of both -- Part of
+ the quicksort algorithm. The values of LEFT and RIGHT are undefined
+ after calling this function.
+
+ At each iteration, add another item to the merged list by taking the
+ lowest valued item from the head of either LEFT or RIGHT, determined
+ by passing those items and USERDATA to COMPARE. COMPARE should return
+ less than 0 if the head of LEFT has the lower value, greater than 0 if
+ the head of RIGHT has the lower value, otherwise 0. */
+static SList *
+slist_sort_merge (SList *left, SList *right, SListCompare *compare,
+ void *userdata)
{
- size_t n;
+ SList merged, *insert;
- for (n = 0; head; ++n)
- head = head->next;
+ insert = &merged;
- return n;
+ while (left && right)
+ {
+ if ((*compare) (left, right, userdata) <= 0)
+ {
+ insert = insert->next = left;
+ left = left->next;
+ }
+ else
+ {
+ insert = insert->next = right;
+ right = right->next;
+ }
+ }
+
+ insert->next = left ? left : right;
+
+ return merged.next;
}
+/* Perform a destructive quicksort on the items in SLIST, by repeatedly
+ calling COMPARE with a pair of items from SLIST along with USERDATA
+ at every iteration. COMPARE is a function as defined above for
+ slist_sort_merge(). The value of SLIST is undefined after calling
+ this function.
+
+ e.g. slist = slist_sort (slist, compare, 0); */
SList *
-slist_reverse (SList *head)
+slist_sort (SList *slist, SListCompare *compare, void *userdata)
{
- SList *result = 0;
- SList *next;
+ SList *left, *right;
- while (head)
+ if (!slist)
+ return slist;
+
+ /* Be sure that LEFT and RIGHT never contain the same item. */
+ left = slist;
+ right = slist->next;
+
+ /* Skip two items with RIGHT and one with SLIST, until RIGHT falls off
+ the end. SLIST must be about half way along. */
+ while (right && (right = right->next))
{
- next = head->next;
- head->next = result;
- result = head;
- head = next;
+ if (!right || !(right = right->next))
+ break;
+ slist = slist->next;
}
+ right = slist->next;
+ slist->next = 0;
- return result;
+ /* Sort LEFT and RIGHT, then merge the two. */
+ return slist_sort_merge (slist_sort (left, compare, userdata),
+ slist_sort (right, compare, userdata),
+ compare, userdata);
}
-int
-slist_foreach (SList *head, SListCallback *foreach, const void *userdata)
+
+/* Aside from using the functions above to manage chained structures of
+ any type that has a NEXT pointer as its first field, SLISTs can
+ be comprised of boxed items. The boxes are chained together in
+ that case, so there is no need for a NEXT field in the item proper.
+ Some care must be taken to slist_box and slist_unbox each item in
+ a boxed list at the appropriate points to avoid leaking the memory
+ used for the boxes. It us usually a very bad idea to mix boxed and
+ non-boxed items in a single list. */
+
+/* Return a `boxed' freshly mallocated 1 element list containing
+ USERDATA. */
+SList *
+slist_box (const void *userdata)
{
- assert (foreach);
+ SList *item = malloc (sizeof *item);
- for (; head; head = head->next)
- if ((*foreach) (head, userdata) < 0)
- return -1;
+ if (item)
+ {
+ item->next = 0;
+ item->userdata = userdata;
+ }
- return 0;
+ return item;
+}
+
+/* Return the contents of a `boxed' ITEM, recycling the box itself. */
+void *
+slist_unbox (SList *item)
+{
+ void *userdata = 0;
+
+ if (item)
+ {
+ /* Strip the const, because responsibility for this memory
+ passes to the caller on return. */
+ userdata = (void *) item->userdata;
+ free (item);
+ }
+
+ return userdata;
}
/* slist.h -- generalised singly linked lists
Copyright (C) 2000, 2004 Free Software Foundation, Inc.
- Originally by Gary V. Vaughan <gary@gnu.org>
+ Written by Gary V. Vaughan <gary@gnu.org>
NOTE: The canonical source of this file is maintained with the
GNU Libtool package. Report bugs to bug-libtool@gnu.org.
typedef struct slist {
struct slist *next; /* chain forward pointer*/
- const void * userdata; /* incase you want to use raw `SList's */
+ const void *userdata; /* for boxed `SList' item */
} SList;
-typedef void * SListCompare (const SList *node, const void *userdata);
-typedef int SListCallback (const SList *node, const void *userdata);
+typedef void * SListCallback (SList *item, void *userdata);
+typedef int SListCompare (const SList *item1, const SList *item2,
+ void *userdata);
-LT_SCOPE SList *slist_new (const void *userdata);
-LT_SCOPE SList *slist_delete (SList *head, void (*delete) (void *data));
-LT_SCOPE void * slist_remove (SList **phead, const void *match,
- SListCompare *find);
LT_SCOPE SList *slist_concat (SList *head, SList *tail);
-LT_SCOPE SList *slist_cons (SList *head, SList *tail);
-LT_SCOPE SList *slist_tail (SList *head);
-LT_SCOPE SList *slist_nth (SList *head, size_t n);
-LT_SCOPE void * slist_find (SList *head, const void *match,
- SListCompare *find);
-LT_SCOPE size_t slist_length (SList *head);
-LT_SCOPE SList *slist_reverse (SList *head);
-LT_SCOPE int slist_foreach (SList *head, SListCallback *foreach,
- const void *userdata);
+LT_SCOPE SList *slist_cons (SList *item, SList *slist);
+
+LT_SCOPE SList *slist_delete (SList *slist, void (*delete) (void *item));
+LT_SCOPE void * slist_remove (SList **phead, SListCallback *find,
+ void *matchdata);
+LT_SCOPE SList *slist_reverse (SList *slist);
+LT_SCOPE SList *slist_sort (SList *slist, SListCompare *compare,
+ void *userdata);
+
+LT_SCOPE SList *slist_tail (SList *slist);
+LT_SCOPE SList *slist_nth (SList *slist, size_t n);
+LT_SCOPE void * slist_find (SList *slist, SListCallback *find,
+ void *matchdata);
+LT_SCOPE size_t slist_length (SList *slist);
+
+LT_SCOPE void * slist_foreach (SList *slist, SListCallback *foreach,
+ void *userdata);
+
+LT_SCOPE SList *slist_box (const void *userdata);
+LT_SCOPE void * slist_unbox (SList *item);
LT_END_C_DECLS
projects / thirdparty / libtool.git / commitdiff
