MySQL 8.4.3
Source Code Documentation
queues.h
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23
24#ifndef QUEUES_INCLUDED
25#define QUEUES_INCLUDED
26
27/**
28 @file storage/myisam/queues.h
29 Code for handling of priority queues.
30 Implementation of queues from "Algorithms in C" by Robert Sedgewick.
31*/
32
33#include <stddef.h>
34#include <sys/types.h>
35
36#include "my_inttypes.h"
38
39#ifdef __cplusplus
40extern "C" {
41#endif
42
43struct QUEUE {
48 uint offset_to_key; /* compare is done on element+offset */
49 int max_at_top; /* Normally 1, set to -1 if queue_top gives max */
50 int (*compare)(void *, uchar *, uchar *);
52};
53
54void _downheap(QUEUE *queue, uint idx);
55void queue_fix(QUEUE *queue);
56
57#define queue_top(queue) ((queue)->root[1])
58#define queue_element(queue, index) ((queue)->root[index + 1])
59#define queue_end(queue) ((queue)->root[(queue)->elements])
60
61static inline void queue_replaced(QUEUE *queue) { _downheap(queue, 1); }
62
63static inline void queue_set_max_at_top(QUEUE *queue, int set_arg) {
64 queue->max_at_top = set_arg ? -1 : 1;
65}
66
67typedef int (*queue_compare)(void *, uchar *, uchar *);
68
69int init_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements,
70 uint offset_to_key, bool max_at_top, queue_compare compare,
71 void *first_cmp_arg);
72int reinit_queue(QUEUE *queue, PSI_memory_key psi_key, uint max_elements,
73 uint offset_to_key, bool max_at_top, queue_compare compare,
74 void *first_cmp_arg);
76void queue_insert(QUEUE *queue, uchar *element);
77uchar *queue_remove(QUEUE *queue, uint idx);
78
79static inline void queue_remove_all(QUEUE *queue) { queue->elements = 0; }
80
81static inline bool queue_is_full(QUEUE *queue) {
82 return queue->elements == queue->max_elements;
83}
84
85static inline bool is_queue_inited(QUEUE *queue) {
86 return queue->root != nullptr;
87}
88
89#ifdef __cplusplus
90}
91#endif
92
93#endif // QUEUES_INCLUDED
unsigned int PSI_memory_key
Instrumented memory key.
Definition: psi_memory_bits.h:49
Some integer typedefs for easier portability.
unsigned char uchar
Definition: my_inttypes.h:52
static QUEUE queue
Definition: myisampack.cc:210
Performance schema instrumentation interface.
static bool queue_is_full(QUEUE *queue)
Definition: queues.h:81
static bool is_queue_inited(QUEUE *queue)
Definition: queues.h:85
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)
void _downheap(QUEUE *queue, uint idx)
Definition: queues.cc:210
uchar * queue_remove(QUEUE *queue, uint idx)
Definition: queues.cc:201
void delete_queue(QUEUE *queue)
Definition: queues.cc:174
void queue_fix(QUEUE *queue)
Definition: queues.cc:258
static void queue_replaced(QUEUE *queue)
Definition: queues.h:61
void queue_insert(QUEUE *queue, uchar *element)
Definition: queues.cc:182
int(* queue_compare)(void *, uchar *, uchar *)
Definition: queues.h:67
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)
static void queue_remove_all(QUEUE *queue)
Definition: queues.h:79
static void queue_set_max_at_top(QUEUE *queue, int set_arg)
Definition: queues.h:63
static int compare(size_t a, size_t b)
Function to compare two size_t integers for their relative order.
Definition: rpl_utility.cc:107
Definition: queues.h:43
uint auto_extent
Definition: queues.h:51
uchar ** root
Definition: queues.h:44
int(* compare)(void *, uchar *, uchar *)
Definition: queues.h:50
void * first_cmp_arg
Definition: queues.h:45
int max_at_top
Definition: queues.h:49
uint max_elements
Definition: queues.h:47
uint elements
Definition: queues.h:46
uint offset_to_key
Definition: queues.h:48