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#pragma once
#include "itextstream.h"
#include <stdio.h>
// A wrapper around a file input stream opened for reading in text mode. Similar to std::ifstream.
class TextFileInputStream :
public TextInputStream
{
private:
FILE* _file;
public:
TextFileInputStream(const std::string& name) :
_file(!name.empty() ? fopen(name.c_str(), "rt") : NULL)
{}
virtual ~TextFileInputStream()
{
if (!failed())
{
fclose(_file);
}
}
bool failed() const
{
return _file == 0;
}
std::size_t read(char* buffer, std::size_t length) override
{
return fread(buffer, 1, length, _file);
}
// greebo: Override default std::streambuf::seekoff() method to provide buffer positioning capabilities
virtual std::streampos seekoff(std::streamoff off,
std::ios_base::seekdir way,
std::ios_base::openmode which = std::ios_base::in | std::ios_base::out) override
{
if (way == std::ios_base::beg)
{
// Invalidate the buffer of our base class to force an underflow
setg(_buffer, _buffer, _buffer);
if (fseek(_file, static_cast<long>(off), SEEK_SET))
{
return std::streampos(-1); // error
}
}
else if (way == std::ios_base::cur)
{
if (fseek(_file, static_cast<long>(off), SEEK_CUR))
{
return std::streampos(-1); // error
}
else
{
// success, check if we need to invalidate our controlled input sequence
if (gptr() + off > egptr() || gptr() + off < eback())
{
setg(_buffer, _buffer, _buffer);
}
}
}
else if (way == std::ios_base::end)
{
// Invalidate the buffer of our base class to force an underflow
setg(_buffer, _buffer, _buffer);
if (fseek(_file, static_cast<long>(off), SEEK_END))
{
return std::streampos(-1); // error
}
}
return std::streampos(ftell(_file));
}
};
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