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/* Copyright (c) 2002 Jeff Johnston <jjohnstn@redhat.com> */
/* 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.
*/
#define _DEFAULT_SOURCE
#include <stdlib.h>
static const char R64_ARRAY[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
char *
l64a(long value)
{
char *ptr;
char *result;
int i, index;
unsigned long tmp = (unsigned long)value & 0xffffffff;
static __THREAD_LOCAL char _l64a_buf[8];
result = _l64a_buf;
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;
}
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