1 /**
2 * @file lv_utils.c
3 *
4 */
5
6 /*********************
7 * INCLUDES
8 *********************/
9 #include <stddef.h>
10
11 #include "lv_utils.h"
12
13 /*********************
14 * DEFINES
15 *********************/
16
17 /**********************
18 * TYPEDEFS
19 **********************/
20
21 /**********************
22 * STATIC PROTOTYPES
23 **********************/
24
25 /**********************
26 * STATIC VARIABLES
27 **********************/
28
29 /**********************
30 * MACROS
31 **********************/
32
33 /**********************
34 * GLOBAL FUNCTIONS
35 **********************/
36
37 /** Searches base[0] to base[n - 1] for an item that matches *key.
38 *
39 * @note The function cmp must return negative if its first
40 * argument (the search key) is less than its second (a table entry),
41 * zero if equal, and positive if greater.
42 *
43 * @note Items in the array must be in ascending order.
44 *
45 * @param key Pointer to item being searched for
46 * @param base Pointer to first element to search
47 * @param n Number of elements
48 * @param size Size of each element
49 * @param cmp Pointer to comparison function (see #unicode_list_compare as a comparison function
50 * example)
51 *
52 * @return a pointer to a matching item, or NULL if none exists.
53 */
_lv_utils_bsearch(const void * key,const void * base,uint32_t n,uint32_t size,int32_t (* cmp)(const void * pRef,const void * pElement))54 void * _lv_utils_bsearch(const void * key, const void * base, uint32_t n, uint32_t size,
55 int32_t (*cmp)(const void * pRef, const void * pElement))
56 {
57 const char * middle;
58 int32_t c;
59
60 for(middle = base; n != 0;) {
61 middle += (n / 2) * size;
62 if((c = (*cmp)(key, middle)) > 0) {
63 n = (n / 2) - ((n & 1) == 0);
64 base = (middle += size);
65 }
66 else if(c < 0) {
67 n /= 2;
68 middle = base;
69 }
70 else {
71 return (char *)middle;
72 }
73 }
74 return NULL;
75 }
76
77 /**********************
78 * STATIC FUNCTIONS
79 **********************/
80
