man3/a64l.3

   1 .\" Copyright 2002 walter harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\" Distributed under GPL
   3 .\"
   4 .\" Corrected, aeb, 2002-05-30
   5 .\"
   6 .TH A64L 3 2002-02-15 "" "Linux Programmer's Manual"
   7 .SH NAME
   8 a64l, l64a \- convert between long and base-64
   9 .SH SYNOPSIS
  10 .B #include <stdlib.h>
  11 .sp
  12 .BI "long a64l(char *" str64 );
  13 .sp
  14 .BI "char *l64a(long " value );
  15 .SH DESCRIPTION
  16 These functions provide a conversion between 32-bit long integers
  17 and little-endian base-64 ASCII strings (of length zero to six).
  18 If the string used as argument for
  19 .BR a64l ()
  20 has length greater than six, only the first six bytes are used.
  21 If longs have more than 32 bits, then
  22 .BR l64a ()
  23 uses only the low order 32 bits of
  24 .IR value ,
  25 and
  26 .BR a64l ()
  27 sign-extends its 32-bit result.
  28 .LP
  29 The 64 digits in the base 64 system are:
  30 .RS
  31 .nf
  32
  33 \&'.'   represents a 0
  34 \&'/'   represents a 1
  35 0-9     represent  2-11
  36 A-Z     represent 12-37
  37 a-z     represent 38-63
  38
  39 .fi
  40 .RE
  41 So 123 = 59*64^0 + 1*64^1 = "v/".
  42 .SH NOTES
  43 The value returned by
  44 .BR a64l ()
  45 may be a pointer to a static buffer, possibly overwritten
  46 by later calls.
  47 .LP
  48 The behaviour of
  49 .BR l64a ()
  50 is undefined when
  51 .I value
  52 is negative.
  53 If
  54 .I value
  55 is zero, it returns an empty string.
  56 .LP
  57 These functions are broken in glibc before 2.2.5
  58 (puts most significant digit first).
  59 .LP
  60 This is not the encoding used by
  61 .BR uuencode (1).
  62 .SH "CONFORMING TO"
  63 POSIX.1-2001.
  64 .SH "SEE ALSO"
  65 .BR uuencode (1),
  66 .BR itoa (3),
  67 .BR strtoul (3)