75 lines
1.4 KiB
C
75 lines
1.4 KiB
C
/*
|
|
FUNCTION
|
|
<<utoa>>---unsigned integer to string
|
|
|
|
INDEX
|
|
utoa
|
|
|
|
SYNOPSIS
|
|
#include <stdlib.h>
|
|
char *utoa(unsigned <[value]>, char *<[str]>, int <[base]>);
|
|
char *__utoa(unsigned <[value]>, char *<[str]>, int <[base]>);
|
|
|
|
DESCRIPTION
|
|
<<utoa>> converts the unsigned integer [<value>] to a null-terminated string
|
|
using the specified base, which must be between 2 and 36, inclusive.
|
|
<[str]> should be an array long enough to contain the converted
|
|
value, which in the worst case is sizeof(int)*8+1 bytes.
|
|
|
|
RETURNS
|
|
A pointer to the string, <[str]>, or NULL if <[base]> is invalid.
|
|
|
|
PORTABILITY
|
|
<<utoa>> is non-ANSI.
|
|
|
|
No supporting OS subroutine calls are required.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
|
|
char *
|
|
__utoa (unsigned value,
|
|
char *str,
|
|
int base)
|
|
{
|
|
const char digits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
|
|
int i, j;
|
|
unsigned remainder;
|
|
char c;
|
|
|
|
/* Check base is supported. */
|
|
if ((base < 2) || (base > 36))
|
|
{
|
|
str[0] = '\0';
|
|
return NULL;
|
|
}
|
|
|
|
/* Convert to string. Digits are in reverse order. */
|
|
i = 0;
|
|
do
|
|
{
|
|
remainder = value % base;
|
|
str[i++] = digits[remainder];
|
|
value = value / base;
|
|
} while (value != 0);
|
|
str[i] = '\0';
|
|
|
|
/* Reverse string. */
|
|
for (j = 0, i--; j < i; j++, i--)
|
|
{
|
|
c = str[j];
|
|
str[j] = str[i];
|
|
str[i] = c;
|
|
}
|
|
|
|
return str;
|
|
}
|
|
|
|
char *
|
|
utoa (unsigned value,
|
|
char *str,
|
|
int base)
|
|
{
|
|
return __utoa (value, str, base);
|
|
}
|