1 files changed, 79 insertions, 0 deletions
diff --git a/src/libbio/bgetc.c b/src/libbio/bgetc.c
new file mode 100644
index 000000000..52ed241f9
--- /dev/null
+++ b/src/libbio/bgetc.c
@@ -0,0 +1,79 @@
+/*
+http://code.google.com/p/inferno-os/source/browse/libbio/bgetc.c
+
+	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+	Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com).  All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include	<u.h>
+#include	<libc.h>
+#include	<bio.h>
+
+int
+Bgetc(Biobuf *bp)
+{
+	int i;
+
+loop:
+	i = bp->icount;
+	if(i != 0) {
+		bp->icount = i+1;
+		return bp->ebuf[i];
+	}
+	if(bp->state != Bractive) {
+		if(bp->state == Bracteof)
+			bp->state = Bractive;
+		return Beof;
+	}
+	/*
+	 * get next buffer, try to keep Bungetsize
+	 * characters pre-catenated from the previous
+	 * buffer to allow that many ungets.
+	 */
+	memmove(bp->bbuf-Bungetsize, bp->ebuf-Bungetsize, Bungetsize);
+	i = read(bp->fid, bp->bbuf, bp->bsize);
+	bp->gbuf = bp->bbuf;
+	if(i <= 0) {
+		bp->state = Bracteof;
+		if(i < 0)
+			bp->state = Binactive;
+		return Beof;
+	}
+	if(i < bp->bsize) {
+		memmove(bp->ebuf-i-Bungetsize, bp->bbuf-Bungetsize, i+Bungetsize);
+		bp->gbuf = bp->ebuf-i;
+	}
+	bp->icount = -i;
+	bp->offset += i;
+	goto loop;
+}
+
+int
+Bungetc(Biobuf *bp)
+{
+
+	if(bp->state == Bracteof)
+		bp->state = Bractive;
+	if(bp->state != Bractive)
+		return Beof;
+	bp->icount--;
+	return 1;
+}