PersonalVotingMachine/extended-setup/components/lvgl/src/lv_misc/lv_utils.c
2020-12-22 14:30:09 +02:00

116 lines
2.7 KiB
C

/**
* @file lv_utils.c
*
*/
/*********************
* INCLUDES
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#include <stdbool.h>
#include "lv_utils.h"
#include "lv_math.h"
/*********************
* DEFINES
*********************/
/**********************
* TYPEDEFS
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/**********************
* STATIC PROTOTYPES
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/**********************
* STATIC VARIABLES
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/**********************
* MACROS
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/**********************
* GLOBAL FUNCTIONS
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/**
* Convert a number to string
* @param num a number
* @param buf pointer to a `char` buffer. The result will be stored here (max 10 elements)
* @return same as `buf` (just for convenience)
*/
char * lv_utils_num_to_str(int32_t num, char * buf)
{
if(num == 0) {
buf[0] = '0';
buf[1] = '\0';
return buf;
}
int8_t digitCount = 0;
int8_t i = 0;
if(num < 0) {
buf[digitCount++] = '-';
num = LV_MATH_ABS(num);
++i;
}
while(num) {
char digit = num % 10;
buf[digitCount++] = digit + 48;
num /= 10;
}
buf[digitCount] = '\0';
digitCount--;
while(digitCount > i) {
char temp = buf[i];
buf[i] = buf[digitCount];
buf[digitCount] = temp;
digitCount--;
i++;
}
return buf;
}
/** Searches base[0] to base[n - 1] for an item that matches *key.
*
* @note The function cmp must return negative if its first
* argument (the search key) is less that its second (a table entry),
* zero if equal, and positive if greater.
*
* @note Items in the array must be in ascending order.
*
* @param key Pointer to item being searched for
* @param base Pointer to first element to search
* @param n Number of elements
* @param size Size of each element
* @param cmp Pointer to comparison function (see #lv_font_codeCompare as a comparison function
* example)
*
* @return a pointer to a matching item, or NULL if none exists.
*/
void * lv_utils_bsearch(const void * key, const void * base, uint32_t n, uint32_t size,
int32_t (*cmp)(const void * pRef, const void * pElement))
{
const char * middle;
int32_t c;
for(middle = base; n != 0;) {
middle += (n / 2) * size;
if((c = (*cmp)(key, middle)) > 0) {
n = (n / 2) - ((n & 1) == 0);
base = (middle += size);
} else if(c < 0) {
n /= 2;
middle = base;
} else {
return (char *)middle;
}
}
return NULL;
}
/**********************
* STATIC FUNCTIONS
**********************/