MySQL  8.0.21
Source Code Documentation
queues.h
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22 
23 #ifndef QUEUES_INCLUDED
24 #define QUEUES_INCLUDED
25 
26 /**
27  @file storage/myisam/queues.h
28  Code for handling of priority queues.
29  Implementation of queues from "Algoritms in C" by Robert Sedgewick.
30 */
31 
32 #include <stddef.h>
33 #include <sys/types.h>
34 
35 #include "my_inttypes.h"
36 #include "mysql/psi/psi_memory.h"
37 
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41 
42 struct QUEUE {
47  uint offset_to_key; /* compare is done on element+offset */
48  int max_at_top; /* Normally 1, set to -1 if queue_top gives max */
49  int (*compare)(void *, uchar *, uchar *);
51 };
52 
53 void _downheap(QUEUE *queue, uint idx);
54 void queue_fix(QUEUE *queue);
55 
56 #define queue_top(queue) ((queue)->root[1])
57 #define queue_element(queue, index) ((queue)->root[index + 1])
58 #define queue_end(queue) ((queue)->root[(queue)->elements])
59 
60 static inline void queue_replaced(QUEUE *queue) { _downheap(queue, 1); }
61 
62 static inline void queue_set_max_at_top(QUEUE *queue, int set_arg) {
63  queue->max_at_top = set_arg ? -1 : 1;
64 }
65 
66 typedef int (*queue_compare)(void *, uchar *, uchar *);
67 
70  void *first_cmp_arg);
73  void *first_cmp_arg);
74 void delete_queue(QUEUE *queue);
75 void queue_insert(QUEUE *queue, uchar *element);
76 uchar *queue_remove(QUEUE *queue, uint idx);
77 
78 static inline void queue_remove_all(QUEUE *queue) { queue->elements = 0; }
79 
80 static inline bool queue_is_full(QUEUE *queue) {
81  return queue->elements == queue->max_elements;
82 }
83 
84 static inline bool is_queue_inited(QUEUE *queue) {
85  return queue->root != nullptr;
86 }
87 
88 #ifdef __cplusplus
89 }
90 #endif
91 
92 #endif // QUEUES_INCLUDED
unsigned char uchar
Definition: my_inttypes.h:51
void queue_fix(QUEUE *queue)
Definition: queues.cc:257
Some integer typedefs for easier portability.
static void queue_set_max_at_top(QUEUE *queue, int set_arg)
Definition: queues.h:62
static bool is_queue_inited(QUEUE *queue)
Definition: queues.h:84
static QUEUE queue
Definition: myisampack.cc:206
uint offset_to_key
Definition: queues.h:47
void queue_insert(QUEUE *queue, uchar *element)
Definition: queues.cc:181
static bool queue_is_full(QUEUE *queue)
Definition: queues.h:80
static void queue_remove_all(QUEUE *queue)
Definition: queues.h:78
unsigned int PSI_memory_key
Instrumented memory key.
Definition: psi_memory_bits.h:46
void * first_cmp_arg
Definition: queues.h:44
Definition: queues.h:42
static void queue_replaced(QUEUE *queue)
Definition: queues.h:60
uint auto_extent
Definition: queues.h:50
uchar ** root
Definition: queues.h:43
unsigned int uint
Definition: uca-dump.cc:29
void _downheap(QUEUE *queue, uint idx)
Definition: queues.cc:209
int max_at_top
Definition: queues.h:48
int reinit_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements, uint offset_to_key, bool max_at_top, queue_compare compare, void *first_cmp_arg)
uchar * queue_remove(QUEUE *queue, uint idx)
Definition: queues.cc:200
Performance schema instrumentation interface.
int(* compare)(void *, uchar *, uchar *)
Definition: queues.h:49
int(* queue_compare)(void *, uchar *, uchar *)
Definition: queues.h:66
int init_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements, uint offset_to_key, bool max_at_top, queue_compare compare, void *first_cmp_arg)
uint elements
Definition: queues.h:45
uint max_elements
Definition: queues.h:46
void delete_queue(QUEUE *queue)
Definition: queues.cc:173