stdlib/a64l.3

   1 .\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
   2 .\" All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. The name of the author may not be used to endorse or promote products
  13 .\"    derived from this software without specific prior written permission.
  14 .\"
  15 .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  16 .\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  17 .\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
  18 .\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19 .\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20 .\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  21 .\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  22 .\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  23 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  24 .\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25 .\"
  26 .\" $OpenBSD: a64l.3,v 1.5 2000/04/20 13:50:01 aaron Exp $
  27 .\"
  28 .Dd August 17, 1997
  29 .Dt A64L 3
  30 .Os
  31 .Sh NAME
  32 .Nm a64l ,
  33 .Nm l64a
  34 .Nd convert between 32-bit integer and radix-64 ASCII string
  35 .Sh SYNOPSIS
  36 .Fd #include <stdlib.h>
  37 .Ft long
  38 .Fn a64l "const char *s"
  39 .Ft char *
  40 .Fn l64a "long value"
  41 .Sh DESCRIPTION
  42 The
  43 .Fn a64l
  44 and
  45 .Fn l64a
  46 functions are used to maintain numbers stored in radix-64
  47 .Tn ASCII
  48 characters.
  49 This is a notation by which 32-bit integers
  50 can be represented by up to six characters; each character represents a
  51 .Dq digit
  52 in a radix-64 notation.
  53 .Pp
  54 The characters used to represent digits are
  55 .Ql \&.
  56 for 0,
  57 .Ql /
  58 for 1,
  59 .Ql 0
  60 through
  61 .Ql 9
  62 for 2-11,
  63 .Ql A
  64 through
  65 .Ql Z
  66 for 12-37, and
  67 .Ql a
  68 through
  69 .Ql z
  70 for 38-63.
  71 .Pp
  72 The
  73 .Fn a64l
  74 function takes a pointer to a null-terminated radix-64 representation
  75 and returns a corresponding 32-bit value.
  76 If the string pointed to by
  77 .Fa s
  78 contains more than six characters,
  79 .Fn a64l
  80 will use the first six.
  81 .Fn a64l
  82 scans the character string from left to right, decoding
  83 each character as a 6-bit radix-64 number.
  84 If a long integer is
  85 larger than 32 bits, the return value will be sign-extended.
  86 .Pp
  87 .Fn l64a
  88 takes a long integer argument
  89 .Fa value
  90 and returns a pointer to the corresponding radix-64 representation.
  91 .Sh RETURN VALUES
  92 On success,
  93 .Fn a64l
  94 returns a 32-bit representation of
  95 .Fa s .
  96 If
  97 .Fa s
  98 is a null pointer or if it contains digits other than those described above.
  99 .Fn a64l
 100 returns \-1 and sets the global variable
 101 .Va errno
 102 to
 103 .Er EINVAL .
 104 .Pp
 105 On success,
 106 .Fn l64a
 107 returns a pointer to a string containing the radix-64 representation of
 108 .Fa value .
 109 If
 110 .Fa value
 111 is 0,
 112 .Fn l64a
 113 returns a pointer to the empty string.
 114 If
 115 .Fa value
 116 is negative,
 117 .Fn l64a
 118 returns a null pointer and sets the global variable
 119 .Va errno
 120 to
 121 .Er EINVAL .
 122 .Sh WARNINGS
 123 The value returned by
 124 .Fn l64a
 125 is a pointer into a static buffer, the contents of which
 126 will be overwritten by subsequent calls.
 127 .Pp
 128 The value returned by
 129 .Fn a64l
 130 may be incorrect if the value is too large; for that reason, only strings
 131 that resulted from a call to
 132 .Fn l64a
 133 should be used to call
 134 .Fn a64l .
 135 .Pp
 136 If a long integer is larger than 32 bits, only the low-order
 137 32 bits are used.
 138 .Sh STANDARDS
 139 The
 140 .Fn a64l
 141 and
 142 .Fn l64a
 143 functions conform to
 144 .St -xpg4.2 .