1 files changed, 69 insertions, 0 deletions
diff --git a/usr/src/lib/libast/common/string/fmtbuf.c b/usr/src/lib/libast/common/string/fmtbuf.c
new file mode 100644
index 0000000000..3035fb5612
--- /dev/null
+++ b/usr/src/lib/libast/common/string/fmtbuf.c
@@ -0,0 +1,69 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*           Copyright (c) 1985-2007 AT&T Knowledge Ventures            *
+*                      and is licensed under the                       *
+*                  Common Public License, Version 1.0                  *
+*                      by AT&T Knowledge Ventures                      *
+*                                                                      *
+*                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;
+}