/*====================================================================* - 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_QUEUE_H #define LEPTONICA_QUEUE_H /*! * \file queue.h * *
* Expandable pointer queue for arbitrary void* data. * * The L_Queue is a fifo that implements a queue of void* pointers. * It can be used to hold a queue of any type of struct. * * Internally, it maintains two counters: * nhead: location of head (in ptrs) from the beginning * of the array. * nelem: number of ptr elements stored in the queue. * * The element at the head of the queue, which is the next to * be removed, is array[nhead]. The location at the tail of the * queue to which the next element will be added is * array[nhead + nelem]. * * As items are added to the queue, nelem increases. * As items are removed, nhead increases and nelem decreases. * Any time the tail reaches the end of the allocated array, * all the pointers are shifted to the left, so that the head * is at the beginning of the array. * If the array becomes more than 3/4 full, it doubles in size. * * The auxiliary stack can be used in a wrapper for re-using * items popped from the queue. It is not made by default. * * For further implementation details, see queue.c. **/ /*! Expandable pointer queue for arbitrary void* data */ struct L_Queue { l_int32 nalloc; /*!< size of allocated ptr array */ l_int32 nhead; /*!< location of head (in ptrs) from the */ /*!< beginning of the array */ l_int32 nelem; /*!< number of elements stored in the queue */ void **array; /*!< ptr array */ struct L_Stack *stack; /*!< auxiliary stack */ }; typedef struct L_Queue L_QUEUE; #endif /* LEPTONICA_QUEUE_H */