1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1985-2007 AT&T Knowledge Ventures * 5 * and is licensed under the * 6 * Common Public License, Version 1.0 * 7 * by AT&T Knowledge Ventures * 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 33 static char buf[16 * 1024]; 34 static char* nxt = buf; 35 static int lck = -1; 36 37 static char* big; 38 static size_t bigsiz; 39 40 char* 41 fmtbuf(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