fmtbuf.c revision 3e14f97f673e8a630f076077de35afdd43dc1587
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2010 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
#include <ast.h>
/*
* return small format buffer chunk of size n
* spin lock for thread access
* format buffers are short lived
* only one concurrent buffer with size > sizeof(buf)
*/
static char buf[16 * 1024];
static char* nxt = buf;
static int lck = -1;
static char* big;
static size_t bigsiz;
char*
fmtbuf(size_t n)
{
register char* cur;
while (++lck)
lck--;
if (n > (&buf[elementsof(buf)] - nxt))
{
if (n > elementsof(buf))
{
if (n > bigsiz)
{
bigsiz = roundof(n, 8 * 1024);
if (!(big = newof(big, char, bigsiz, 0)))
{
lck--;
return 0;
}
}
lck--;
return big;
}
nxt = buf;
}
cur = nxt;
nxt += n;
lck--;
return cur;
}