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 represents 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 â€â€™.â€â€™ (dot) for 0, â€â€™/â€â€™ for 1, â€â€™0â€â€™ through
â€â€™9â€â€™ for [2,11], â€â€™Aâ€â€™ through â€â€™Zâ€â€™ for [12,37], and â€â€™aâ€â€™ through â€â€™zâ€â€™ 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 characters 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 corre-
sponding 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 con-
version 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 original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
POSIX 2003 A64L(P)
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