hashtab.c (find_hash_table_entry): When returning a DELETED_ENTRY slot, change it to EMPTY_ENTRY first.

1999-10-23 08:51 -0700  Zack Weinberg  <zack@bitmover.com>

	* hashtab.c (find_hash_table_entry): When returning a
	DELETED_ENTRY slot, change it to EMPTY_ENTRY first.
	(clear_hash_table_slot): New function which deletes an entry
	by its position in the table, not its value.
	(traverse_hash_table): New function which calls a hook
	function for every live entry in the table.

	* hashtab.h: Give hash_table_t a struct tag.  Add prototypes
	for clear_hash_table_slot and traverse_hash_table.  Correct
	prototype of all_hash_table_collisions.

From-SVN: r30138

4 files changed, 59 insertions, 3 deletions

diff --git a/include/ChangeLog b/include/ChangeLog
index cfaab0a..545574f 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,9 @@
+1999-10-23 08:51 -0700  Zack Weinberg  <zack@bitmover.com>
+
+	* hashtab.h: Give hash_table_t a struct tag.  Add prototypes
+	for clear_hash_table_slot and traverse_hash_table.  Correct
+	prototype of all_hash_table_collisions.
+
 Fri Oct 15 01:47:51 1999  Vladimir Makarov  <vmakarov@loony.cygnus.com>
 
 	* hashtab.h: New file.
diff --git a/include/hashtab.h b/include/hashtab.h
index 67c37a2..3990c14 100644
--- a/include/hashtab.h
+++ b/include/hashtab.h
@@ -47,7 +47,7 @@ typedef const void *hash_table_entry_t;
    tables.  All work with hash table should be executed only through
    functions mentioned below. */
 
-typedef struct
+typedef struct hash_table
 {
   /* Current size (in entries) of the hash table */
   size_t size;
@@ -88,13 +88,19 @@ extern hash_table_entry_t *find_hash_table_entry
 extern void remove_element_from_hash_table_entry PARAMS ((hash_table_t,
 							  hash_table_entry_t));
 
+extern void clear_hash_table_slot PARAMS ((hash_table_t, hash_table_entry_t *));
+
+extern void traverse_hash_table PARAMS ((hash_table_t,
+					 int (*) (hash_table_entry_t, void *),
+					 void *));
+    
 extern size_t hash_table_size PARAMS ((hash_table_t));
 
 extern size_t hash_table_elements_number PARAMS ((hash_table_t));
 
 extern int hash_table_collisions PARAMS ((hash_table_t));
 
-extern int all_hash_table_collisions ();
+extern int all_hash_table_collisions PARAMS ((void));
 
 #ifdef __cplusplus
 }
diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index 78180af..829b70e 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,12 @@
+1999-10-23 08:51 -0700  Zack Weinberg  <zack@bitmover.com>
+
+	* hashtab.c (find_hash_table_entry): When returning a
+	DELETED_ENTRY slot, change it to EMPTY_ENTRY first.
+	(clear_hash_table_slot): New function which deletes an entry
+	by its position in the table, not its value.
+	(traverse_hash_table): New function which calls a hook
+	function for every live entry in the table.
+
 1999-10-19  Mark Mitchell  <mark@codesourcery.com>
 
 	* cplus-dem.c (INTBUF_SIZE): New macro.
diff --git a/libiberty/hashtab.c b/libiberty/hashtab.c
index 8137d77..9fce8cc 100644
--- a/libiberty/hashtab.c
+++ b/libiberty/hashtab.c
@@ -206,7 +206,7 @@ find_hash_table_entry (htab, element, reserve)
 	      if (first_deleted_entry_ptr != NULL)
 		{
 		  entry_ptr = first_deleted_entry_ptr;
-		  *entry_ptr = DELETED_ENTRY;
+		  *entry_ptr = EMPTY_ENTRY;
 		}
 	    }
           break;
@@ -242,6 +242,41 @@ remove_element_from_hash_table_entry (htab, element)
   htab->number_of_deleted_elements++;
 }
 
+/* This function clears a specified slot in a hash table.
+   It is useful when you've already done the lookup and don't want to
+   do it again.  */
+
+void
+clear_hash_table_slot (htab, slot)
+     hash_table_t htab;
+     hash_table_entry_t *slot;
+{
+  if (slot < htab->entries || slot >= htab->entries + htab->size
+      || *slot == EMPTY_ENTRY || *slot == DELETED_ENTRY)
+    abort ();
+  *slot = DELETED_ENTRY;
+  htab->number_of_deleted_elements++;
+}
+
+/* This function scans over the entire hash table calling
+   CALLBACK for each live entry.  If CALLBACK returns false,
+   the iteration stops.  INFO is passed as CALLBACK's second
+   argument.  */
+
+void
+traverse_hash_table (htab, callback, info)
+     hash_table_t htab;
+     int (*callback) (hash_table_entry_t, void *);
+     void *info;
+{
+  hash_table_entry_t *entry_ptr;
+  for (entry_ptr = htab->entries; entry_ptr < htab->entries + htab->size;
+       entry_ptr++)
+    if (*entry_ptr != EMPTY_ENTRY && *entry_ptr != DELETED_ENTRY)
+      if (!callback (*entry_ptr, info))
+	break;
+}
+
 /* The following function returns current size of given hash table. */
 
 size_t