1*4887Schin /***********************************************************************
2*4887Schin *                                                                      *
3*4887Schin *               This software is part of the ast package               *
4*4887Schin *           Copyright (c) 1985-2007 AT&T Knowledge Ventures            *
5*4887Schin *                      and is licensed under the                       *
6*4887Schin *                  Common Public License, Version 1.0                  *
7*4887Schin *                      by AT&T Knowledge Ventures                      *
8*4887Schin *                                                                      *
9*4887Schin *                A copy of the License is available at                 *
10*4887Schin *            http://www.opensource.org/licenses/cpl1.0.txt             *
11*4887Schin *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12*4887Schin *                                                                      *
13*4887Schin *              Information and Software Systems Research               *
14*4887Schin *                            AT&T Research                             *
15*4887Schin *                           Florham Park NJ                            *
16*4887Schin *                                                                      *
17*4887Schin *                 Glenn Fowler <gsf@research.att.com>                  *
18*4887Schin *                  David Korn <dgk@research.att.com>                   *
19*4887Schin *                   Phong Vo <kpv@research.att.com>                    *
20*4887Schin *                                                                      *
21*4887Schin ***********************************************************************/
22*4887Schin #pragma prototyped
23*4887Schin 
24*4887Schin #include <ast.h>
25*4887Schin 
26*4887Schin /*
27*4887Schin  * return small format buffer chunk of size n
28*4887Schin  * spin lock for thread access
29*4887Schin  * format buffers are short lived
30*4887Schin  * only one concurrent buffer with size > sizeof(buf)
31*4887Schin  */
32*4887Schin 
33*4887Schin static char		buf[16 * 1024];
34*4887Schin static char*		nxt = buf;
35*4887Schin static int		lck = -1;
36*4887Schin 
37*4887Schin static char*		big;
38*4887Schin static size_t		bigsiz;
39*4887Schin 
40*4887Schin char*
41*4887Schin fmtbuf(size_t n)
42*4887Schin {
43*4887Schin 	register char*	cur;
44*4887Schin 
45*4887Schin 	while (++lck)
46*4887Schin 		lck--;
47*4887Schin 	if (n > (&buf[elementsof(buf)] - nxt))
48*4887Schin 	{
49*4887Schin 		if (n > elementsof(buf))
50*4887Schin 		{
51*4887Schin 			if (n > bigsiz)
52*4887Schin 			{
53*4887Schin 				bigsiz = roundof(n, 8 * 1024);
54*4887Schin 				if (!(big = newof(big, char, bigsiz, 0)))
55*4887Schin 				{
56*4887Schin 					lck--;
57*4887Schin 					return 0;
58*4887Schin 				}
59*4887Schin 			}
60*4887Schin 			lck--;
61*4887Schin 			return big;
62*4887Schin 		}
63*4887Schin 		nxt = buf;
64*4887Schin 	}
65*4887Schin 	cur = nxt;
66*4887Schin 	nxt += n;
67*4887Schin 	lck--;
68*4887Schin 	return cur;
69*4887Schin }
70