| /*====================================================================* |
| - 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_QUEUE_H |
| #define LEPTONICA_QUEUE_H |
| |
| /* |
| * 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. |
| */ |
| |
| 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 */ |