78 lines
3.4 KiB
C
78 lines
3.4 KiB
C
/*====================================================================*
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- Copyright (C) 2001 Leptonica. All rights reserved.
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-
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- Redistribution and use in source and binary forms, with or without
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- modification, are permitted provided that the following conditions
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- are met:
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- 1. Redistributions of source code must retain the above copyright
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- notice, this list of conditions and the following disclaimer.
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- 2. Redistributions in binary form must reproduce the above
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- copyright notice, this list of conditions and the following
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- disclaimer in the documentation and/or other materials
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- provided with the distribution.
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-
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- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
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- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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- OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*====================================================================*/
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#ifndef LEPTONICA_QUEUE_H
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#define LEPTONICA_QUEUE_H
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/*!
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* \file queue.h
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*
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* <pre>
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* Expandable pointer queue for arbitrary void* data.
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*
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* The L_Queue is a fifo that implements a queue of void* pointers.
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* It can be used to hold a queue of any type of struct.
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*
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* Internally, it maintains two counters:
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* nhead: location of head (in ptrs) from the beginning
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* of the array.
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* nelem: number of ptr elements stored in the queue.
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*
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* The element at the head of the queue, which is the next to
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* be removed, is array[nhead]. The location at the tail of the
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* queue to which the next element will be added is
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* array[nhead + nelem].
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*
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* As items are added to the queue, nelem increases.
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* As items are removed, nhead increases and nelem decreases.
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* Any time the tail reaches the end of the allocated array,
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* all the pointers are shifted to the left, so that the head
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* is at the beginning of the array.
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* If the array becomes more than 3/4 full, it doubles in size.
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*
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* The auxiliary stack can be used in a wrapper for re-using
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* items popped from the queue. It is not made by default.
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*
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* For further implementation details, see queue.c.
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* </pre>
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*/
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/*! Expandable pointer queue for arbitrary void* data */
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struct L_Queue
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{
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l_int32 nalloc; /*!< size of allocated ptr array */
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l_int32 nhead; /*!< location of head (in ptrs) from the */
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/*!< beginning of the array */
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l_int32 nelem; /*!< number of elements stored in the queue */
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void **array; /*!< ptr array */
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struct L_Stack *stack; /*!< auxiliary stack */
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};
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typedef struct L_Queue L_QUEUE;
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#endif /* LEPTONICA_QUEUE_H */
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