1 files changed, 238 insertions, 0 deletions
diff --git a/src/util/vbuf.c b/src/util/vbuf.c
new file mode 100644
index 0000000..924e230
--- /dev/null
+++ b/src/util/vbuf.c
@@ -0,0 +1,238 @@
+/*++
+/* NAME
+/*	vbuf 3
+/* SUMMARY
+/*	generic buffer package
+/* SYNOPSIS
+/*	#include <vbuf.h>
+/*
+/*	int	VBUF_GET(bp)
+/*	VBUF	*bp;
+/*
+/*	int	VBUF_PUT(bp, ch)
+/*	VBUF	*bp;
+/*	int	ch;
+/*
+/*	int	VBUF_SPACE(bp, len)
+/*	VBUF	*bp;
+/*	ssize_t	len;
+/*
+/*	int	vbuf_unget(bp, ch)
+/*	VBUF	*bp;
+/*	int	ch;
+/*
+/*	ssize_t	vbuf_read(bp, buf, len)
+/*	VBUF	*bp;
+/*	void	*buf;
+/*	ssize_t	len;
+/*
+/*	ssize_t	vbuf_write(bp, buf, len)
+/*	VBUF	*bp;
+/*	const void *buf;
+/*	ssize_t	len;
+/*
+/*	int	vbuf_err(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_eof(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_timeout(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_clearerr(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_rd_err(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_wr_err(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_rd_timeout(bp)
+/*	VBUF	*bp;
+/*
+/*	int	vbuf_wr_timeout(bp)
+/*	VBUF	*bp;
+/* DESCRIPTION
+/*	This module implements a buffer with read/write primitives that
+/*	automatically handle buffer-empty or buffer-full conditions.
+/*	The application is expected to provide callback routines that run
+/*	when the read-write primitives detect a buffer-empty/full condition.
+/*
+/*	VBUF buffers provide primitives to store and retrieve characters,
+/*	and to look up buffer status information.
+/*	By design, VBUF buffers provide no explicit primitives for buffer
+/*	memory management. This is left to the application to avoid any bias
+/*	toward specific management models. The application is free to use
+/*	whatever strategy suits best: memory-resident buffer, memory mapped
+/*	file, or stdio-like window to an open file.
+/*
+/*	VBUF_GET() returns the next character from the specified buffer,
+/*	or VBUF_EOF when none is available. VBUF_GET() is an unsafe macro
+/*	that evaluates its argument more than once.
+/*
+/*	VBUF_PUT() stores one character into the specified buffer. The result
+/*	is the stored character, or VBUF_EOF in case of problems. VBUF_PUT()
+/*	is an unsafe macro that evaluates its arguments more than once.
+/*
+/*	VBUF_SPACE() requests that the requested amount of buffer space be
+/*	made available, so that it can be accessed without using VBUF_PUT().
+/*	The result value is 0 for success, VBUF_EOF for problems.
+/*	VBUF_SPACE() is an unsafe macro that evaluates its arguments more
+/*	than once. VBUF_SPACE() does not support read-only streams.
+/*
+/*	vbuf_unget() provides at least one character of pushback, and returns
+/*	the pushed back character, or VBUF_EOF in case of problems. It is
+/*	an error to call vbuf_unget() on a buffer before reading any data
+/*	from it. vbuf_unget() clears the buffer's end-of-file indicator upon
+/*	success, and sets the buffer's error indicator when an attempt is
+/*	made to push back a non-character value.
+/*
+/*	vbuf_read() and vbuf_write() do bulk I/O. The result value is the
+/*	number of bytes transferred. A short count is returned in case of
+/*	an error.
+/*
+/*	vbuf_timeout() is a macro that returns non-zero if a timeout error
+/*	condition was detected while reading or writing the buffer. The
+/*	error status can be reset by calling vbuf_clearerr().
+/*
+/*	vbuf_err() is a macro that returns non-zero if a non-EOF error
+/*	(including timeout) condition was detected while reading or writing
+/*	the buffer. The error status can be reset by calling vbuf_clearerr().
+/*
+/*	The vbuf_rd_mumble() and vbuf_wr_mumble() macros report on
+/*	read and write error conditions, respectively.
+/*
+/*	vbuf_eof() is a macro that returns non-zero if an end-of-file
+/*	condition was detected while reading or writing the buffer. The error
+/*	status can be reset by calling vbuf_clearerr().
+/* APPLICATION CALLBACK SYNOPSIS
+/*	int	get_ready(bp)
+/*	VBUF	*bp;
+/*
+/*	int	put_ready(bp)
+/*	VBUF	*bp;
+/*
+/*	int	space(bp, len)
+/*	VBUF	*bp;
+/*	ssize_t	len;
+/* APPLICATION CALLBACK DESCRIPTION
+/* .ad
+/* .fi
+/*	get_ready() is called when VBUF_GET() detects a buffer-empty condition.
+/*	The result is zero when more data could be read, VBUF_EOF otherwise.
+/*
+/*	put_ready() is called when VBUF_PUT() detects a buffer-full condition.
+/*	The result is zero when the buffer could be flushed, VBUF_EOF otherwise.
+/*
+/*	space() performs whatever magic necessary to make at least \fIlen\fR
+/*	bytes available for access without using VBUF_PUT(). The result is 0
+/*	in case of success, VBUF_EOF otherwise.
+/* SEE ALSO
+/*	vbuf(3h) layout of the VBUF data structure.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include "sys_defs.h"
+#include <string.h>
+
+/* Utility library. */
+
+#include "vbuf.h"
+
+/* vbuf_unget - implement at least one character pushback */
+
+int     vbuf_unget(VBUF *bp, int ch)
+{
+    if ((ch & 0xff) != ch || -bp->cnt >= bp->len) {
+	bp->flags |= VBUF_FLAG_RD_ERR;	/* This error affects reads! */
+	return (VBUF_EOF);
+    } else {
+	bp->cnt--;
+	bp->flags &= ~VBUF_FLAG_EOF;
+	return (*--bp->ptr = ch);
+    }
+}
+
+/* vbuf_get - handle read buffer empty condition */
+
+int     vbuf_get(VBUF *bp)
+{
+    return (bp->get_ready(bp) ?
+	((bp->flags |= VBUF_FLAG_EOF), VBUF_EOF) : VBUF_GET(bp));
+}
+
+/* vbuf_put - handle write buffer full condition */
+
+int     vbuf_put(VBUF *bp, int ch)
+{
+    return (bp->put_ready(bp) ? VBUF_EOF : VBUF_PUT(bp, ch));
+}
+
+/* vbuf_read - bulk read from buffer */
+
+ssize_t vbuf_read(VBUF *bp, void *buf, ssize_t len)
+{
+    ssize_t count;
+    void   *cp;
+    ssize_t n;
+
+#if 0
+    for (count = 0; count < len; count++)
+	if ((buf[count] = VBUF_GET(bp)) < 0)
+	    break;
+    return (count);
+#else
+    for (cp = buf, count = len; count > 0; cp += n, count -= n) {
+	if (bp->cnt >= 0 && bp->get_ready(bp))
+	    break;
+	n = (count < -bp->cnt ? count : -bp->cnt);
+	memcpy(cp, bp->ptr, n);
+	bp->ptr += n;
+	bp->cnt += n;
+    }
+    return (len - count);
+#endif
+}
+
+/* vbuf_write - bulk write to buffer */
+
+ssize_t vbuf_write(VBUF *bp, const void *buf, ssize_t len)
+{
+    ssize_t count;
+    const void *cp;
+    ssize_t n;
+
+#if 0
+    for (count = 0; count < len; count++)
+	if (VBUF_PUT(bp, buf[count]) < 0)
+	    break;
+    return (count);
+#else
+    for (cp = buf, count = len; count > 0; cp += n, count -= n) {
+	if (bp->cnt <= 0 && bp->put_ready(bp) != 0)
+	    break;
+	n = (count < bp->cnt ? count : bp->cnt);
+	memcpy(bp->ptr, cp, n);
+	bp->ptr += n;
+	bp->cnt -= n;
+    }
+    return (len - count);
+#endif
+}