1 /*
2  * Copyright 1987 by MIT Student Information Processing Board
3  *
4  * Permission to use, copy, modify, and distribute this software and
5  * its documentation for any purpose is hereby granted, provided that
6  * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
7  * advertising or publicity pertaining to distribution of the software
8  * without specific, written prior permission.  M.I.T. and the
9  * M.I.T. S.I.P.B. make no representations about the suitability of
10  * this software for any purpose.  It is provided "as is" without
11  * express or implied warranty.
12  */
13 
14 #include "com_err.h"
15 #include "error_table.h"
16 #include "internal.h"
17 
18 static const char char_set[] =
19 	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_";
20 
21 static char buf[6];
22 
error_table_name(errcode_t num)23 const char * error_table_name(errcode_t num)
24 {
25     int ch;
26     int i;
27     char *p;
28 
29     /* num = aa aaa abb bbb bcc ccc cdd ddd d?? ??? ??? */
30     p = buf;
31     num >>= ERRCODE_RANGE;
32     /* num = ?? ??? ??? aaa aaa bbb bbb ccc ccc ddd ddd */
33     num &= 077777777L;
34     /* num = 00 000 000 aaa aaa bbb bbb ccc ccc ddd ddd */
35     for (i = 4; i >= 0; i--) {
36 	ch = (int)((num >> BITS_PER_CHAR * i) & ((1 << BITS_PER_CHAR) - 1));
37 	if (ch != 0)
38 	    *p++ = char_set[ch-1];
39     }
40     *p = '\0';
41     return(buf);
42 }
43