A64L(P) A64L(P)
NAME
a64l, l64a - convert between a 32-bit integer and a radix-64 ASCII string
SYNOPSIS
#include <stdlib.h>
long a64l(const char *s);
char *l64a(long value);
DESCRIPTION
These functions maintain numbers stored in radix-64 ASCII characters. This is a notation
by which 32-bit integers can be represented by up to six characters; each character repre-
sents a digit in radix-64 notation. If the type long contains more than 32 bits, only the
low-order 32 bits shall be used for these operations.
The characters used to represent digits are '.' (dot) for 0, '/' for 1, '0' through '9'
for [2,11], 'A' through 'Z' for [12,37], and 'a' through 'z' for [38,63].
The a64l() function shall take a pointer to a radix-64 representation, in which the first
digit is the least significant, and return the corresponding long value. If the string
pointed to by s contains more than six characters, a64l() shall use the first six. If the
first six characters of the string contain a null terminator, a64l() shall use only char-
acters preceding the null terminator. The a64l() function shall scan the character string
from left to right with the least significant digit on the left, decoding each character
as a 6-bit radix-64 number. If the type long contains more than 32 bits, the resulting
value is sign-extended. The behavior of a64l() is unspecified if s is a null pointer or
the string pointed to by s was not generated by a previous call to l64a().
The l64a() function shall take a long argument and return a pointer to the corresponding
radix-64 representation. The behavior of l64a() is unspecified if value is negative.
The value returned by l64a() may be a pointer into a static buffer. Subsequent calls to
l64a() may overwrite the buffer.
The l64a() function need not be reentrant. A function that is not required to be reentrant
is not required to be thread-safe.
RETURN VALUE
Upon successful completion, a64l() shall return the long value resulting from conversion
of the input string. If a string pointed to by s is an empty string, a64l() shall return
0L.
The l64a() function shall return a pointer to the radix-64 representation. If value is
0L, l64a() shall return a pointer to an empty string.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
If the type long contains more than 32 bits, the result of a64l(l64a(x)) is x in the low-
order 32 bits.
RATIONALE
This is not the same encoding as used by either encoding variant of the uuencode utility.
FUTURE DIRECTIONS
None.
SEE ALSO
strtoul() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>, the Shell and
Utilities volume of IEEE Std 1003.1-2001, uuencode
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
POSIX 2003 A64L(P)
|