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Diffstat (limited to 'leptonica/src/list.h')
| -rw-r--r-- | leptonica/src/list.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/leptonica/src/list.h b/leptonica/src/list.h new file mode 100644 index 00000000..d207e79f --- /dev/null +++ b/leptonica/src/list.h @@ -0,0 +1,90 @@ +/*====================================================================* + - Copyright (C) 2001 Leptonica. All rights reserved. + - + - Redistribution and use in source and binary forms, with or without + - modification, are permitted provided that the following conditions + - are met: + - 1. Redistributions of source code must retain the above copyright + - notice, this list of conditions and the following disclaimer. + - 2. Redistributions in binary form must reproduce the above + - copyright notice, this list of conditions and the following + - disclaimer in the documentation and/or other materials + - provided with the distribution. + - + - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY + - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + - OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + *====================================================================*/ + + +#ifndef LEPTONICA_LIST_H +#define LEPTONICA_LIST_H + +/*! + * \file list.h + * + * <pre> + * 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 + * </pre> + */ + +struct DoubleLinkedList +{ + struct DoubleLinkedList *prev; + struct DoubleLinkedList *next; + void *data; +}; +typedef struct DoubleLinkedList DLLIST; + + + /*! Simple list traverse macro - forward */ +#define L_BEGIN_LIST_FORWARD(head, element) \ + { \ + DLLIST *_leptvar_nextelem_; \ + for ((element) = (head); (element); (element) = _leptvar_nextelem_) { \ + _leptvar_nextelem_ = (element)->next; + + + /*! Simple list traverse macro - reverse */ +#define L_BEGIN_LIST_REVERSE(tail, element) \ + { \ + DLLIST *_leptvar_prevelem_; \ + for ((element) = (tail); (element); (element) = _leptvar_prevelem_) { \ + _leptvar_prevelem_ = (element)->prev; + + + /*! Simple list traverse macro - end of a list traverse */ +#define L_END_LIST }} + + +#endif /* LEPTONICA_LIST_H */ |