file.cpp

MySQL源码文件5.X系列, 可自已编译到服务器

/*
   Copyright (C) 2000-2007 MySQL AB

   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; version 2 of the License.

   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; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
   MA  02110-1301  USA.
*/

/* file.cpp implements File Sources and Sinks
*/

#include "runtime.hpp"
#include "file.hpp"


namespace TaoCrypt {


FileSource::FileSource(const char* fname, Source& source)
{
    file_ = fopen(fname, "rb");
    if (file_) get(source);
}


FileSource::~FileSource()
{
    if (file_)
        fclose(file_);
}



// return size of source from beginning or current position
word32 FileSource::size(bool use_current)
{
    long current = ftell(file_);
    long begin   = current;

    if (!use_current) {
        fseek(file_, 0, SEEK_SET);
        begin = ftell(file_);
    }

    fseek(file_, 0, SEEK_END);
    long end = ftell(file_);

    fseek(file_, current, SEEK_SET);

    return end - begin;
}


word32 FileSource::size_left()
{
    return size(true);
}


// fill file source from source
word32 FileSource::get(Source& source)
{
    word32 sz(size());
    if (source.size() < sz)
        source.grow(sz);

    size_t bytes = fread(source.buffer_.get_buffer(), 1, sz, file_);

    if (bytes == 1)
        return sz;
    else
        return 0;
}


FileSink::FileSink(const char* fname, Source& source)
{
    file_ = fopen(fname, "wb");
    if (file_) put(source);
}


FileSink::~FileSink()
{
    if (file_)
        fclose(file_);
}


// fill source from file sink
void FileSink::put(Source& source)
{
    fwrite(source.get_buffer(), 1, source.size(), file_);
}


// swap with other and reset to beginning
void Source::reset(ByteBlock& otherBlock)
{
    buffer_.Swap(otherBlock);   
    current_ = 0;
}


}  // namespace