Change naming convention of POSIX emulation layer for Windows

Use prefix w32 instead of posix: Rename posixfile.c, posixio.c to
w32file.c, w32io.c.  Rename posix_accept(), posix_bind(),
posix_close(), posix_fd2socket(), posix_listen(), posix_mkdir(),
posix_setsockopt(), posix_shutdown(), posix_socket() to w32_accept(),
w32_bind(), w32_fd2socket(), w32_list(), w32_mkdir(),
w32_setsockopt(), w32_shutdown(), w32_socket().

src/lib/w32/w32io.c

@@ -0,0 +1,137 @@
+/*
+ *  Empire - A multi-player, client/server Internet based war game.
+ *  Copyright (C) 1986-2009, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *                           Ken Stevens, Steve McClure
+ *
+ *  This program 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 2 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  ---
+ *
+ *  See files README, COPYING and CREDITS in the root of the source
+ *  tree for related information and legal notices.  It is expected
+ *  that future projects/authors will amend these files as needed.
+ *
+ *  ---
+ *
+ *  w32io.c: POSIX I/O emulation layer for Windows
+ *
+ *  Known contributors to this file:
+ *     Ron Koenderink, 2007
+ *     Markus Armbruster, 2007-2009
+ */
+
+/*
+ * POSIX sockets are file descriptors.  Windows sockets are something
+ * else, with a separate set of functions to operate on them.  To
+ * present a more POSIX-like interface to our application code, we
+ * provide a compatibility layer that wraps file descriptors around
+ * sockets.
+ */
+
+#include <config.h>
+
+#include <errno.h>
+#include <io.h>
+#include <stdlib.h>
+#include <string.h>
+#include "misc.h"
+#include "sys/uio.h"
+
+int (*w32_close_function)(int) = _close;
+int (*w32_read_function)(int, void *, unsigned) = _read;
+int (*w32_write_function)(int, const void *, unsigned) = _write;
+
+/*
+ * POSIX equivalent for readv
+ * Modelled after the GNU's libc/sysdeps/posix/readv.c
+ */
+ssize_t
+readv(int fd, const struct iovec *iov, int iovcnt)
+{
+    int i;
+    unsigned char *buffer, *buffer_location;
+    size_t total_bytes = 0;
+    int bytes_read;
+    size_t bytes_left;
+
+    for (i = 0; i < iovcnt; i++) {
+	total_bytes += iov[i].iov_len;
+    }
+
+    buffer = malloc(total_bytes);
+    if (buffer == NULL && total_bytes != 0) {
+	errno = ENOMEM;
+	return -1;
+    }
+
+    bytes_read = read(fd, buffer, total_bytes);
+    if (bytes_read <= 0) {
+	free(buffer);
+	return -1;
+    }
+
+    bytes_left = bytes_read;
+    buffer_location = buffer;
+    for (i = 0; i < iovcnt; i++) {
+	size_t copy = MIN(iov[i].iov_len, bytes_left);
+
+	memcpy(iov[i].iov_base, buffer_location, copy);
+
+	buffer_location += copy;
+	bytes_left -= copy;
+	if (bytes_left == 0)
+	    break;
+    }
+
+    free(buffer);
+
+    return bytes_read;
+}
+
+/*
+ * POSIX equivalent for writev
+ * Modelled after the GNU's libc/sysdeps/posix/writev.c
+ */
+ssize_t
+writev(int fd, const struct iovec *iov, int iovcnt)
+{
+    int i;
+    unsigned char *buffer, *buffer_location;
+    size_t total_bytes = 0;
+    int bytes_written;
+
+    for (i = 0; i < iovcnt; i++)
+	total_bytes += iov[i].iov_len;
+
+    buffer = malloc(total_bytes);
+    if (buffer == NULL && total_bytes != 0) {
+	errno = ENOMEM;
+	return -1;
+    }
+
+    buffer_location = buffer;
+    for (i = 0; i < iovcnt; i++) {
+	memcpy(buffer_location, iov[i].iov_base, iov[i].iov_len);
+	buffer_location += iov[i].iov_len;
+    }
+
+    bytes_written = write(fd, buffer, total_bytes);
+
+    free(buffer);
+
+    if (bytes_written <= 0)
+	return -1;
+    return bytes_written;
+}