writefile.cpp

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/* xoreos - A reimplementation of BioWare's Aurora engine
 *
 * xoreos is the legal property of its developers, whose names
 * can be found in the AUTHORS file distributed with this source
 * distribution.
 *
 * xoreos 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.
 *
 * xoreos 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 xoreos. If not, see <http://www.gnu.org/licenses/>.
 */

#include <cassert>

#include "src/common/writefile.h"
#include "src/common/error.h"
#include "src/common/ustring.h"
#include "src/common/platform.h"
#include "src/common/filepath.h"

namespace Common {

WriteFile::WriteFile() : _handle(0), _size(0) {
}

WriteFile::WriteFile(const UString &fileName) : _handle(0), _size(0) {
    if (!open(fileName))
        throw Exception("Can't open file \"%s\" for writing", fileName.c_str());
}

WriteFile::~WriteFile() {
    try {
        close();
    } catch (...) {
    }
}

bool WriteFile::open(const UString &fileName) {
    close();

    UString path = FilePath::normalize(fileName);
    if (path.empty())
        return false;

    try {
        FilePath::createDirectories(FilePath::getDirectory(path));
    } catch (...) {
        return false;
    }

    if (!(_handle = Platform::openFile(path, Platform::kFileModeWrite)))
        return false;

    return true;
}

void WriteFile::close() {
    flush();

    if (_handle)
        std::fclose(_handle);

    _handle = 0;
    _size   = 0;
}

bool WriteFile::isOpen() const {
    return _handle != 0;
}

void WriteFile::flush() {
    if (!_handle)
        return;

    if (std::fflush(_handle) != 0)
        throw Exception(kWriteError);
}

size_t WriteFile::write(const void *dataPtr, size_t dataSize) {
    if (!_handle)
        return 0;

    assert(dataPtr);

    const ptrdiff_t oldPos = pos();
    const ptrdiff_t written = std::fwrite(dataPtr, 1, dataSize, _handle);
    _size += MAX<ptrdiff_t>(0, -static_cast<ptrdiff_t>(size()) + oldPos + written);

    return written;
}

size_t WriteFile::size() const {
    return _size;
}

size_t WriteFile::pos() const {
    return std::ftell(_handle);
}

size_t WriteFile::seek(ptrdiff_t offset, SeekableWriteStream::Origin whence) {
    const size_t oldPos = pos();
    const size_t newPos = evalSeek(offset, whence, pos(), 0, size());

    if (newPos > _size)
        throw Exception(kSeekError);

    if (std::fseek(_handle, newPos, SEEK_SET))
        throw Exception(kSeekError);

    return oldPos;
}

} // End of namespace Common