xref: /illumos-gate/usr/src/lib/libc/port/gen/l64a.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * convert long int to base 64 ascii
32  * char set is [./0-9A-Za-z]
33  * two's complement negatives are assumed,
34  * but no assumptions are made about sign propagation on right shift
35  *
36  */
37 
38 #include "lint.h"
39 #include "mtlib.h"
40 #include "libc.h"
41 #include <values.h>
42 #include <synch.h>
43 #include <thread.h>
44 #include <stdlib.h>
45 #include <sys/types.h>
46 #include "tsd.h"
47 
48 #define	BITSPERCHAR	6 /* to hold entire character set */
49 #define	BITSUSED	(BITSPERBYTE * sizeof (int))
50 #define	NMAX		((BITSUSED + BITSPERCHAR - 1)/BITSPERCHAR)
51 #define	SIGN		(-(1 << (BITSUSED - BITSPERCHAR - 1)))
52 #define	CHARMASK	((1 << BITSPERCHAR) - 1)
53 #define	WORDMASK	((1 << ((NMAX - 1) * BITSPERCHAR)) - 1)
54 
55 char *
56 l64a(long value)
57 {
58 	/* XPG4: only the lower 32 bits are used */
59 	int lg = (int)value;
60 	char *buf = tsdalloc(_T_L64A, NMAX + 1, NULL);
61 	char *s = buf;
62 
63 	if (buf == NULL)
64 		return (NULL);
65 
66 	while (lg != 0) {
67 
68 		int c = (lg & CHARMASK) + ('0' - 2);
69 
70 		if (c > '9')
71 			c += 'A' - '9' - 1;
72 		if (c > 'Z')
73 			c += 'a' - 'Z' - 1;
74 		*s++ = (char)c;
75 		/* fill high-order CHAR if negative */
76 		/* but suppress sign propagation */
77 		lg = ((lg < 0) ? (lg >> BITSPERCHAR) | SIGN :
78 		    lg >> BITSPERCHAR) & WORDMASK;
79 	}
80 	*s = '\0';
81 	return (buf);
82 }
83