Refactor headers

[wimlib] / src / file_io.c

diff --git a/src/file_io.c b/src/file_io.c
new file mode 100644 (file)
index 0000000..7a36732
--- /dev/null
+++ b/src/file_io.c
@@ -0,0 +1,168 @@
+/*
+ * file_io.c - Helper functions for reading and writing to file descriptors.
+ */
+
+/*
+ * Copyright (C) 2013 Eric Biggers
+ *
+ * This file is part of wimlib, a library for working with WIM files.
+ *
+ * wimlib is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * wimlib 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 General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include "wimlib/file_io.h"
+#ifdef __WIN32__
+#  include "wimlib/win32.h" /* For pread(), pwrite() replacements */
+#else
+#  include <sys/uio.h> /* for writev() and `struct iovec' */
+#endif
+
+#include <errno.h>
+#include <unistd.h>
+
+
+/* Like read(), but keep trying until everything has been written or we know for
+ * sure that there was an error (or end-of-file). */
+size_t
+full_read(int fd, void *buf, size_t count)
+{
+       ssize_t bytes_read;
+       size_t bytes_remaining;
+
+       for (bytes_remaining = count;
+            bytes_remaining != 0;
+            bytes_remaining -= bytes_read, buf += bytes_read)
+       {
+               bytes_read = read(fd, buf, bytes_remaining);
+               if (bytes_read <= 0) {
+                       if (bytes_read == 0)
+                               errno = EIO;
+                       else if (errno == EINTR)
+                               continue;
+                       break;
+               }
+       }
+       return count - bytes_remaining;
+}
+
+/* Like write(), but keep trying until everything has been written or we know
+ * for sure that there was an error. */
+size_t
+full_write(int fd, const void *buf, size_t count)
+{
+       ssize_t bytes_written;
+       size_t bytes_remaining;
+
+       for (bytes_remaining = count;
+            bytes_remaining != 0;
+            bytes_remaining -= bytes_written, buf += bytes_written)
+       {
+               bytes_written = write(fd, buf, bytes_remaining);
+               if (bytes_written < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       break;
+               }
+       }
+       return count - bytes_remaining;
+}
+
+/* Like pread(), but keep trying until everything has been read or we know for
+ * sure that there was an error (or end-of-file) */
+size_t
+full_pread(int fd, void *buf, size_t count, off_t offset)
+{
+       ssize_t bytes_read;
+       size_t bytes_remaining;
+
+       for (bytes_remaining = count;
+            bytes_remaining != 0;
+            bytes_remaining -= bytes_read, buf += bytes_read,
+               offset += bytes_read)
+       {
+               bytes_read = pread(fd, buf, bytes_remaining, offset);
+               if (bytes_read <= 0) {
+                       if (bytes_read == 0)
+                               errno = EIO;
+                       else if (errno == EINTR)
+                               continue;
+                       break;
+               }
+       }
+       return count - bytes_remaining;
+}
+
+/* Like pwrite(), but keep trying until everything has been written or we know
+ * for sure that there was an error. */
+size_t
+full_pwrite(int fd, const void *buf, size_t count, off_t offset)
+{
+       ssize_t bytes_written;
+       size_t bytes_remaining;
+
+       for (bytes_remaining = count;
+            bytes_remaining != 0;
+            bytes_remaining -= bytes_written, buf += bytes_written,
+               offset += bytes_written)
+       {
+               bytes_written = pwrite(fd, buf, bytes_remaining, offset);
+               if (bytes_written < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       break;
+               }
+       }
+       return count - bytes_remaining;
+}
+
+/* Like writev(), but keep trying until everything has been written or we know
+ * for sure that there was an error. */
+size_t
+full_writev(int fd, struct iovec *iov, int iovcnt)
+{
+       size_t total_bytes_written = 0;
+       while (iovcnt > 0) {
+               ssize_t bytes_written;
+
+               bytes_written = writev(fd, iov, iovcnt);
+               if (bytes_written < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       break;
+               }
+               total_bytes_written += bytes_written;
+               while (bytes_written) {
+                       if (bytes_written >= iov[0].iov_len) {
+                               bytes_written -= iov[0].iov_len;
+                               iov++;
+                               iovcnt--;
+                       } else {
+                               iov[0].iov_base += bytes_written;
+                               iov[0].iov_len -= bytes_written;
+                               bytes_written = 0;
+                       }
+               }
+       }
+       return total_bytes_written;
+}
+
+off_t
+filedes_offset(int fd)
+{
+       return lseek(fd, 0, SEEK_CUR);
+}