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authorLudovic Courtès <ludo@gnu.org>2008-11-30 17:48:06 +0100
committerLudovic Courtès <ludo@gnu.org>2008-11-30 18:11:47 +0100
commit9b36a80c79c6c26e8e3016eb5d88ea86f66de368 (patch)
treeda03e867d45c2fe705f6fbcb7e727be1a93e5fd4 /lib/full-write.c
parentaa7a939cbfffcb9afefee45ec51834971e4e9787 (diff)
downloadguile-9b36a80c79c6c26e8e3016eb5d88ea86f66de368.tar.gz
Use Gnulib's `full-write' and `full-read' modules.
Diffstat (limited to 'lib/full-write.c')
-rw-r--r--lib/full-write.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/lib/full-write.c b/lib/full-write.c
new file mode 100644
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--- /dev/null
+++ b/lib/full-write.c
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+/* An interface to read and write that retries (if necessary) until complete.
+
+ Copyright (C) 1993, 1994, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
+ 2004, 2005, 2006 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#ifdef FULL_READ
+# include "full-read.h"
+#else
+# include "full-write.h"
+#endif
+
+#include <errno.h>
+
+#ifdef FULL_READ
+# include "safe-read.h"
+# define safe_rw safe_read
+# define full_rw full_read
+# undef const
+# define const /* empty */
+#else
+# include "safe-write.h"
+# define safe_rw safe_write
+# define full_rw full_write
+#endif
+
+#ifdef FULL_READ
+/* Set errno to zero upon EOF. */
+# define ZERO_BYTE_TRANSFER_ERRNO 0
+#else
+/* Some buggy drivers return 0 when one tries to write beyond
+ a device's end. (Example: Linux 1.2.13 on /dev/fd0.)
+ Set errno to ENOSPC so they get a sensible diagnostic. */
+# define ZERO_BYTE_TRANSFER_ERRNO ENOSPC
+#endif
+
+/* Write(read) COUNT bytes at BUF to(from) descriptor FD, retrying if
+ interrupted or if a partial write(read) occurs. Return the number
+ of bytes transferred.
+ When writing, set errno if fewer than COUNT bytes are written.
+ When reading, if fewer than COUNT bytes are read, you must examine
+ errno to distinguish failure from EOF (errno == 0). */
+size_t
+full_rw (int fd, const void *buf, size_t count)
+{
+ size_t total = 0;
+ const char *ptr = (const char *) buf;
+
+ while (count > 0)
+ {
+ size_t n_rw = safe_rw (fd, ptr, count);
+ if (n_rw == (size_t) -1)
+ break;
+ if (n_rw == 0)
+ {
+ errno = ZERO_BYTE_TRANSFER_ERRNO;
+ break;
+ }
+ total += n_rw;
+ ptr += n_rw;
+ count -= n_rw;
+ }
+
+ return total;
+}