1/***********************************************************************
2*                                                                      *
3*               This software is part of the ast package               *
4*          Copyright (c) 1985-2010 AT&T Intellectual Property          *
5*                      and is licensed under the                       *
6*                  Common Public License, Version 1.0                  *
7*                    by AT&T Intellectual Property                     *
8*                                                                      *
9*                A copy of the License is available at                 *
10*            http://www.opensource.org/licenses/cpl1.0.txt             *
11*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12*                                                                      *
13*              Information and Software Systems Research               *
14*                            AT&T Research                             *
15*                           Florham Park NJ                            *
16*                                                                      *
17*                 Glenn Fowler <gsf@research.att.com>                  *
18*                  David Korn <dgk@research.att.com>                   *
19*                   Phong Vo <kpv@research.att.com>                    *
20*                                                                      *
21***********************************************************************/
22#pragma prototyped
23
24#include <ast.h>
25
26/*
27 * return small format buffer chunk of size n
28 * spin lock for thread access
29 * format buffers are short lived
30 * only one concurrent buffer with size > sizeof(buf)
31 */
32
33static char		buf[16 * 1024];
34static char*		nxt = buf;
35static int		lck = -1;
36
37static char*		big;
38static size_t		bigsiz;
39
40char*
41fmtbuf(size_t n)
42{
43	register char*	cur;
44
45	while (++lck)
46		lck--;
47	if (n > (&buf[elementsof(buf)] - nxt))
48	{
49		if (n > elementsof(buf))
50		{
51			if (n > bigsiz)
52			{
53				bigsiz = roundof(n, 8 * 1024);
54				if (!(big = newof(big, char, bigsiz, 0)))
55				{
56					lck--;
57					return 0;
58				}
59			}
60			lck--;
61			return big;
62		}
63		nxt = buf;
64	}
65	cur = nxt;
66	nxt += n;
67	lck--;
68	return cur;
69}
70