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	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 .