![]() |
Leptonica
1.83.1
Image processing and image analysis suite
|
#include <string.h>
#include "allheaders.h"
Go to the source code of this file.
Functions | |
static l_int32 | lqueueExtendArray (L_QUEUE *lq) |
L_QUEUE * | lqueueCreate (l_int32 nalloc) |
void | lqueueDestroy (L_QUEUE **plq, l_int32 freeflag) |
l_ok | lqueueAdd (L_QUEUE *lq, void *item) |
void * | lqueueRemove (L_QUEUE *lq) |
l_int32 | lqueueGetCount (L_QUEUE *lq) |
l_ok | lqueuePrint (FILE *fp, L_QUEUE *lq) |
Variables | |
static const l_int32 | MIN_BUFFER_SIZE = 20 |
static const l_int32 | INITIAL_BUFFER_ARRAYSIZE = 1024 |
Create/Destroy L_Queue L_QUEUE *lqueueCreate() void *lqueueDestroy() Operations to add/remove to/from a L_Queue l_int32 lqueueAdd() static l_int32 lqueueExtendArray() void *lqueueRemove() Accessors l_int32 lqueueGetCount() Debug output l_int32 lqueuePrint() The lqueue 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 buffer nelem: number of ptr elements stored in the queue 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 buffer, all the pointers are shifted to the left, so that the head is at the beginning of the array. If the buffer becomes more than 3/4 full, it doubles in size. [A circular queue would allow us to skip the shifting and to resize only when the buffer is full. For most applications, the extra work we do for a linear queue is not significant.]
Definition in file queue.c.
l_ok lqueueAdd | ( | L_QUEUE * | lq, |
void * | item | ||
) |
[in] | lq | lqueue |
[in] | item | to be added to the tail of the queue |
Notes: (1) The algorithm is as follows. If the queue is populated to the end of the allocated array, shift all ptrs toward the beginning of the array, so that the head of the queue is at the beginning of the array. Then, if the array is more than 0.75 full, realloc with double the array size. Finally, add the item to the tail of the queue.
Definition at line 184 of file queue.c.
References L_Queue::array, lqueueExtendArray(), L_Queue::nalloc, L_Queue::nelem, and L_Queue::nhead.
Referenced by seedfillGrayInvLow(), and seedfillGrayLow().
L_QUEUE* lqueueCreate | ( | l_int32 | nalloc | ) |
[in] | nalloc | size of ptr array to be alloc'd; 0 for default |
Notes: (1) Allocates a ptr array of given size, and initializes counters.
Definition at line 93 of file queue.c.
Referenced by identifyWatershedBasin(), pixSearchBinaryMaze(), seedfillGrayInvLow(), and seedfillGrayLow().
void lqueueDestroy | ( | L_QUEUE ** | plq, |
l_int32 | freeflag | ||
) |
[in,out] | plq | will be set to null before returning |
[in] | freeflag | TRUE to free each remaining struct in the array |
Notes: (1) If freeflag is TRUE, frees each struct in the array. (2) If freeflag is FALSE but there are elements on the array, gives a warning and destroys the array. This will cause a memory leak of all the items that were on the queue. So if the items require their own destroy function, they must be destroyed before the queue. The same applies to the auxiliary stack, if it is used. (3) To destroy the L_Queue, we destroy the ptr array, then the lqueue, and then null the contents of the input ptr.
Definition at line 132 of file queue.c.
References L_Queue::array, lqueueRemove(), lstackDestroy(), L_Queue::nelem, and L_Queue::stack.
Referenced by seedfillGrayInvLow(), and seedfillGrayLow().
|
static |
[in] | lq | lqueue |
Definition at line 220 of file queue.c.
References L_Queue::array, L_Queue::nalloc, and reallocNew().
Referenced by lqueueAdd().
l_int32 lqueueGetCount | ( | L_QUEUE * | lq | ) |
[in] | lq | lqueue |
Definition at line 276 of file queue.c.
References L_Queue::nelem.
Referenced by seedfillGrayInvLow(), and seedfillGrayLow().
l_ok lqueuePrint | ( | FILE * | fp, |
L_QUEUE * | lq | ||
) |
[in] | fp | file stream |
[in] | lq | lqueue |
Definition at line 296 of file queue.c.
References L_Queue::array, L_Queue::nalloc, L_Queue::nelem, and L_Queue::nhead.
void* lqueueRemove | ( | L_QUEUE * | lq | ) |
[in] | lq | lqueue |
Notes: (1) If this is the last item on the queue, so that the queue becomes empty, nhead is reset to the beginning of the array.
Definition at line 249 of file queue.c.
References L_Queue::array, L_Queue::nelem, and L_Queue::nhead.
Referenced by lqueueDestroy(), seedfillGrayInvLow(), and seedfillGrayLow().