битовое целое число и строка ASCII с основанием системы счисления-64 (bit integer and a radix-64 ASCII string)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
a64l, l64a — convert between a 32-bit integer and a radix-64
ASCII string
Синопсис (Synopsis)
#include <stdlib.h>
long a64l(const char *s);
char *l64a(long value);
Описание (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 '.' (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
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 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 thread-safe.
Возвращаемое значение (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.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (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.
Обоснование (Rationale)
This is not the same encoding as used by either encoding variant
of the uuencode utility.
Будущие направления (Future directions)
None.
Смотри также (See also)
strtoul(3p)
The Base Definitions volume of POSIX.1‐2017, stdlib.h(0p)
The Shell and Utilities volume of POSIX.1‐2017, uuencode(1p)
