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Diffstat (limited to 'leptonica/src/queue.h')
| -rw-r--r-- | leptonica/src/queue.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/leptonica/src/queue.h b/leptonica/src/queue.h new file mode 100644 index 00000000..fd380e83 --- /dev/null +++ b/leptonica/src/queue.h @@ -0,0 +1,77 @@ +/*====================================================================* + - 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 + * + * <pre> + * 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. + * </pre> + */ + +/*! 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 */ |