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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:18:56 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:18:56 +0000
commitb7c15c31519dc44c1f691e0466badd556ffe9423 (patch)
treef944572f288bab482a615e09af627d9a2b6727d8 /src/util/vbuf.c
parentInitial commit. (diff)
downloadpostfix-b7c15c31519dc44c1f691e0466badd556ffe9423.tar.xz
postfix-b7c15c31519dc44c1f691e0466badd556ffe9423.zip
Adding upstream version 3.7.10.upstream/3.7.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/util/vbuf.c')
-rw-r--r--src/util/vbuf.c238
1 files changed, 238 insertions, 0 deletions
diff --git a/src/util/vbuf.c b/src/util/vbuf.c
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+/*++
+/* 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
+}