tesseract/include/list.h
theraysmith 530fa19672 Changes to include for 3.00
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@295 d0cd1f9f-072b-0410-8dd7-cf729c803f20
2009-07-11 02:24:22 +00:00

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C
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/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
- This software is distributed in the hope that it will be
- useful, but with NO WARRANTY OF ANY KIND.
- No author or distributor accepts responsibility to anyone for the
- consequences of using this software, or for whether it serves any
- particular purpose or works at all, unless he or she says so in
- writing. Everyone is granted permission to copy, modify and
- redistribute this source code, for commercial or non-commercial
- purposes, with the following restrictions: (1) the origin of this
- source code must not be misrepresented; (2) modified versions must
- be plainly marked as such; and (3) this notice may not be removed
- or altered from any source or modified source distribution.
*====================================================================*/
#ifndef LEPTONICA_LIST_H
#define LEPTONICA_LIST_H
/*
* list.h
*
* Cell for double-linked lists
*
* This allows composition of a list of cells with
* prev, next and data pointers. Generic data
* structures hang on the list cell data pointers.
*
* The list is not circular because that would add much
* complexity in traversing the list under general
* conditions where list cells can be added and removed.
* The only disadvantage of not having the head point to
* the last cell is that the list must be traversed to
* find its tail. However, this traversal is fast, and
* the listRemoveFromTail() function updates the tail
* so there is no searching overhead with repeated use.
*
* The list macros are used to run through a list, and their
* use is encouraged. They are invoked, e.g., as
*
* DLLIST *head, *elem;
* ...
* L_BEGIN_LIST_FORWARD(head, elem)
* <do something with elem and/or elem->data >
* L_END_LIST
*
*/
struct DoubleLinkedList
{
struct DoubleLinkedList *prev;
struct DoubleLinkedList *next;
void *data;
};
typedef struct DoubleLinkedList DLLIST;
/* Simple list traverse macros */
#define L_BEGIN_LIST_FORWARD(head, element) \
{ \
DLLIST *_leptvar_nextelem_; \
for ((element) = (head); (element); (element) = _leptvar_nextelem_) { \
_leptvar_nextelem_ = (element)->next;
#define L_BEGIN_LIST_REVERSE(tail, element) \
{ \
DLLIST *_leptvar_prevelem_; \
for ((element) = (tail); (element); (element) = _leptvar_prevelem_) { \
_leptvar_prevelem_ = (element)->prev;
#define L_END_LIST }}
#endif /* LEPTONICA_LIST_H */