65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/* l64a - convert long to radix-64 ascii string
|
|
*
|
|
* Conversion is performed on at most 32-bits of input value starting
|
|
* from least significant bits to the most significant bits.
|
|
*
|
|
* The routine splits the input value into groups of 6 bits for up to
|
|
* 32 bits of input. This means that the last group may be 2 bits
|
|
* (bits 30 and 31).
|
|
*
|
|
* Each group of 6 bits forms a value from 0-63 which is converted into
|
|
* a character as follows:
|
|
* 0 = '.'
|
|
* 1 = '/'
|
|
* 2-11 = '0' to '9'
|
|
* 12-37 = 'A' to 'Z'
|
|
* 38-63 = 'a' to 'z'
|
|
*
|
|
* When the remaining bits are zero or all 32 bits have been translated,
|
|
* a nul terminator is appended to the resulting string. An input value of
|
|
* 0 results in an empty string.
|
|
*/
|
|
|
|
#include <_ansi.h>
|
|
#include <stdlib.h>
|
|
#include <reent.h>
|
|
|
|
static const char R64_ARRAY[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
|
|
|
|
char *
|
|
_DEFUN (l64a, (value),
|
|
long value)
|
|
{
|
|
return _l64a_r (_REENT, value);
|
|
}
|
|
|
|
char *
|
|
_DEFUN (_l64a_r, (rptr, value),
|
|
struct _reent *rptr _AND
|
|
long value)
|
|
{
|
|
char *ptr;
|
|
char *result;
|
|
int i, index;
|
|
unsigned long tmp = (unsigned long)value & 0xffffffff;
|
|
|
|
_REENT_CHECK_MISC(rptr);
|
|
result = _REENT_L64A_BUF(rptr);
|
|
ptr = result;
|
|
|
|
for (i = 0; i < 6; ++i)
|
|
{
|
|
if (tmp == 0)
|
|
{
|
|
*ptr = '\0';
|
|
break;
|
|
}
|
|
|
|
index = tmp & (64 - 1);
|
|
*ptr++ = R64_ARRAY[index];
|
|
tmp >>= 6;
|
|
}
|
|
|
|
return result;
|
|
}
|