Add zook's ZenUtils to SVN

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18010 a1c6a512-1295-4272-9138-f99709370657

utils/zenutils/source/shared/file.cpp

@@ -0,0 +1,106 @@
+/* zenutils - Utilities for working with creative firmwares.
+ * Copyright 2007 (c) Rasmus Ry <rasmus.ry{at}gmail.com>
+ *
+ * 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
+ */
+
+#include "file.h"
+#include <fstream>
+
+
+bool shared::read_file(const std::string& filename, bytes& buffer,
+                       std::streampos offset, std::streamsize count)
+{
+    std::ifstream ifs;
+    ifs.open(filename.c_str(), std::ios::binary);
+    if (!ifs)
+    {
+        return false;
+    }
+
+    std::ifstream::pos_type startpos = offset;
+    ifs.seekg(offset, std::ios::beg);
+    if (count == -1)
+        ifs.seekg(0, std::ios::end);
+    else
+        ifs.seekg(count, std::ios::cur);
+    std::ifstream::pos_type endpos = ifs.tellg();
+
+    buffer.resize(endpos-startpos);
+    ifs.seekg(offset, std::ios::beg);
+
+    ifs.read((char*)&buffer[0], endpos-startpos);
+
+    ifs.close();
+    return ifs.good();
+}
+
+
+bool shared::write_file(const std::string& filename, bytes& buffer,
+                        bool truncate, std::streampos offset,
+                        std::streamsize count)
+{
+    std::ios::openmode mode = std::ios::in|std::ios::out|std::ios::binary;
+    if (truncate)
+        mode |= std::ios::trunc;
+
+    std::fstream ofs;
+    ofs.open(filename.c_str(), mode);
+    if (!ofs)
+    {
+        return false;
+    }
+
+    if (count == -1)
+        count = buffer.size();
+    else if (count > buffer.size())
+        return false;
+
+    ofs.seekg(offset, std::ios::beg);
+
+    ofs.write((char*)&buffer[0], count);
+
+    ofs.close();
+    return ofs.good();
+}
+
+bool shared::file_exists(const std::string& filename)
+{
+    std::ifstream ifs;
+    ifs.open(filename.c_str(), std::ios::in);
+    if (ifs.is_open())
+    {
+        ifs.close();
+        return true;
+    }
+    return false;
+}
+
+bool shared::copy_file(const std::string& srcname, const std::string& dstname)
+{
+    bytes buffer;
+    if (!read_file(srcname, buffer))
+        return false;
+    return write_file(dstname, buffer, true);
+}
+
+bool shared::backup_file(const std::string& filename, bool force)
+{
+    std::string backupname = filename + ".bak";
+    if (!force)
+        if (file_exists(backupname))
+            return true;
+    return copy_file(filename, backupname);
+}