I'm trying to get familiar with boost::iostream, so in a example program
I'm writing, I want to read a text from a file and write it to file.
I would use my inherited class from file_source/file_sink as device to
read/write. In the read method, my class needs to add each character with
one and write method needs to subtract one from each character.
First of all, I want to make sure that the reading part of the program
works properly so you can see the code as follow:
#include <boost/iostreams/stream.hpp>#include <fstream>#include
"MyFileSource.h"#include <iostream>using namespace std;using namespace
boost::iostreams;int main(){
MyFileSource<char> fileSource("source.txt");
stream<MyFileSource<char>> myStream(fileSource);
std::cout << myStream.rdbuf();
fileSource.close();
}
and my inherited source device code is as follow:
template <typename charType>class MyFileSource : public
boost::iostreams::file_source
{public:
MyFileSource(const std::string& path) : boost::iostreams::file_source(path)
{
file_path = path;
if (!is_open())
open(path);
seek(0, ios::end);
sizeOfFile = seek(0, ios::cur);
seek(0, ios::beg);
buffer = new charType[sizeOfFile];
}
std::streamsize read(charType*, std::streamsize)
{
std::streamsize readCount =
boost::iostreams::file_source::read(buffer, sizeOfFile);
if (readCount > 0)
{
std::string result(buffer, readCount);
for (char& c : result)
c++;
finalResult = result;
}
return readCount;
}
private:
string file_path;
int sizeOfFile;
charType* buffer;
std::string finalResult;
};
unfortunately, the result of *std::cout << myStream.rdbuf()* with above
read method is nothing while if I delete the read method of MyFileSource
class to use the read method of parent, the result will be correct.
Any help will be appreciated.
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