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#include <fstream>
#include <string>
#include <iostream>
#include "pnm.h"
using namespace std;
namespace pnm
{
bool read_header(std::ifstream& istr, Format& type, unsigned int& width, unsigned int& height)
{
// check magic
if (istr.get() != 'P' )
{
return false;
}
char c_type = static_cast<char>(istr.get());
if (c_type == '6')
{
type = Format::PPM;
}
else if (c_type == '5')
{
type = Format::PGM;
}
else
{
cerr << "Invalid PNM format." << endl;
return false;
}
if (istr.get() != '\n')
{
return false;
}
// skip comments
while (istr.peek() == '#')
{
std::string line;
std::getline(istr, line);
}
// get size
istr >> width >> height;
if (width == 0 || height == 0)
{
return false;
}
// get maxvalue
if (istr.get() != '\n')
{
return false;
}
int max_value = -1;
istr >> max_value;
if (max_value > 255)
{
return false;
}
if (istr.get() != '\n')
{
return false;
}
return true;
}
bool write_header(std::ofstream& ostr, Format type, unsigned int width, unsigned int height)
{
if (type == Format::PGM)
ostr << "P5" << endl;
if (type == Format::PPM)
ostr << "P6" << endl;
ostr << width << " " << height << endl;
ostr << "255" << endl;
return true;
}
} // end of namespace pnm