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+/*  list.c -- A poor implementation of a linked list
+ *  Copyright (C) 2008  SEIKO EPSON CORPORATION
+ *
+ *  License: GPLv2+|iscan
+ *  Authors: AVASYS CORPORATION
+ *
+ *  This file is part of the SANE backend distributed with Image Scan!
+ *
+ *  Image Scan!'s SANE backend is free software.
+ *  You can redistribute it and/or modify it under the terms of the GNU
+ *  General Public License as published by the Free Software Foundation;
+ *  either version 2 of the License or at your option any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *  You ought to have received a copy of the GNU General Public License
+ *  along with this package.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ *  Linking Image Scan!'s SANE backend statically or dynamically with
+ *  other modules is making a combined work based on this SANE backend.
+ *  Thus, the terms and conditions of the GNU General Public License
+ *  cover the whole combination.
+ *
+ *  As a special exception, the copyright holders of Image Scan!'s SANE
+ *  backend give you permission to link Image Scan!'s SANE backend with
+ *  SANE frontends that communicate with Image Scan!'s SANE backend
+ *  solely through the SANE Application Programming Interface,
+ *  regardless of the license terms of these SANE frontends, and to
+ *  copy and distribute the resulting combined work under terms of your
+ *  choice, provided that every copy of the combined work is
+ *  accompanied by a complete copy of the source code of Image Scan!'s
+ *  SANE backend (the version of Image Scan!'s SANE backend used to
+ *  produce the combined work), being distributed under the terms of
+ *  the GNU General Public License plus this exception.  An independent
+ *  module is a module which is not derived from or based on Image
+ *  Scan!'s SANE backend.
+ *
+ *  As a special exception, the copyright holders of Image Scan!'s SANE
+ *  backend give you permission to link Image Scan!'s SANE backend with
+ *  independent modules that communicate with Image Scan!'s SANE
+ *  backend solely through the "Interpreter" interface, regardless of
+ *  the license terms of these independent modules, and to copy and
+ *  distribute the resulting combined work under terms of your choice,
+ *  provided that every copy of the combined work is accompanied by a
+ *  complete copy of the source code of Image Scan!'s SANE backend (the
+ *  version of Image Scan!'s SANE backend used to produce the combined
+ *  work), being distributed under the terms of the GNU General Public
+ *  License plus this exception.  An independent module is a module
+ *  which is not derived from or based on Image Scan!'s SANE backend.
+ *
+ *  Note that people who make modified versions of Image Scan!'s SANE
+ *  backend are not obligated to grant special exceptions for their
+ *  modified versions; it is their choice whether to do so.  The GNU
+ *  General Public License gives permission to release a modified
+ *  version without this exception; this exception also makes it
+ *  possible to release a modified version which carries forward this
+ *  exception.
+ */
+
+
+/*! \file
+    \brief  Implements a linked list.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "list.h"
+
+#include <string.h>
+
+/*! Create a new list.
+ */
+list* list_create ()
+{
+  list* lst = 0;
+  
+  lst = t_calloc (1, list);
+  return lst;
+}
+
+/*! Destroy a list.
+ *  Deletes the list related structures, and the contained data with the
+ *  given destructor function. If a destructor is not provided the data is
+ *  left as is.
+ */
+void list_destroy (list* lst, void (*dtor)(void*))
+{
+  if (!lst) return;
+
+  list_entry* entry = lst->head;
+  list_entry* tmp;
+
+  while (entry != NULL)
+  {
+    if (dtor && entry->data)
+      (*dtor) (entry->data);
+    
+    tmp = entry->next;
+    delete (entry);
+    entry = tmp;
+  }
+
+  delete (lst);
+}
+
+/*! Adds a new element to the end of the list.
+ *  Does *not* make a copy.
+ */
+bool list_append (list* lst, void* new_data)
+{
+  if (!lst) return false;
+
+  list_entry* entry = 0;
+
+  entry = t_calloc (1, list_entry);
+  if (!entry) return false;
+
+  entry->data = new_data;
+
+  if (0 == lst->num_entries)
+    {
+      lst->head = entry;
+      lst->tail = entry;
+      lst->cur = entry;
+    }
+  else
+    {
+      lst->tail->next = entry;
+      lst->tail = entry;
+    }
+
+  lst->num_entries += 1;
+  return true;
+}
+
+/*! Creates a NULL terminated array of pointers to list entries.
+ */
+void** list_normalize (const list *lst)
+{
+  void **nlst;
+
+  if (!lst) return NULL;
+
+  nlst = t_malloc (lst->num_entries + 1, void *);
+  if (nlst)
+    {
+      list *p = (list *) lst;
+      list_entry *cur = p->cur;
+
+      void *entry;
+      int i = 0;
+
+      list_reset (p);
+      while ((entry = list_next (p)))
+        {
+          nlst[i++] = entry;
+        }
+      nlst[i++] = NULL;
+      p->cur = cur;
+    }
+  return nlst;
+}
+
+/*! Obtain the number of elements in the list
+ */
+size_t list_size (list* lst)
+{
+  if (!lst) return 0;
+  return lst->num_entries;
+}
+
+/*! Reset iteration to start from the beginning of the list
+ */
+void list_reset (list* lst)
+{
+  if (!lst) return;
+
+  lst->cur = lst->head;
+}
+
+/*! Proceed to the next element in the list.
+ *  Used to iterate over the list items.
+ */
+void* list_next (list* lst)
+{
+  if (!lst || !lst->cur) return 0;
+
+  void* rv = lst->cur->data;
+  lst->cur = lst->cur->next;
+
+  return rv;
+}