text_diff.cpp

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//
//  Copyright (c) 2005 João Abecasis
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//

#include <fstream>
#include <iostream>
#include <iterator>

#include <boost/spirit/core/scanner/scanner.hpp>
#include <boost/spirit/core/primitives/primitives.hpp>

namespace spirit = boost::spirit;

typedef std::istream_iterator<char, char> iterator;
typedef spirit::scanner<iterator> scanner;

int main(int argc, char * argv[])
{
    if (argc != 3)
    {
        std::cerr << "ERROR: Wrong number of arguments." << std::endl;
        std::cout << "Usage:\n\t" << argv[0] << " file1 file2" << std::endl;

        return 1;
    }

    std::ifstream
        file1(argv[1], std::ios_base::binary | std::ios_base::in),
        file2(argv[2], std::ios_base::binary | std::ios_base::in);

    if (!file1 || !file2)
    {
        std::cerr << "ERROR: Unable to open one or both files." << std::endl;
        return 2;
    }

    file1.unsetf(std::ios_base::skipws);
    file2.unsetf(std::ios_base::skipws);

    iterator
        iter_file1(file1),
        iter_file2(file2);

    scanner
        scan1(iter_file1, iterator()),
        scan2(iter_file2, iterator());

    std::size_t line = 1, column = 1;

    while (!scan1.at_end() && !scan2.at_end())
    {
        if (spirit::eol_p.parse(scan1))
        {
            if (!spirit::eol_p.parse(scan2))
            {
                std::cout << "Files differ at line " << line << ", column " <<
                    column << '.' << std::endl;
                return 3;
            }

            ++line, column = 1;
            continue;
        }

        if (*scan1 != *scan2)
        {
            std::cout << "Files differ at line " << line << ", column " <<
                column << '.' << std::endl;
            return 4;
        }

        ++scan1, ++scan2, ++column;
    }

    if (scan1.at_end() != scan2.at_end())
    {
        std::cout << "Files differ in length." << std::endl;
        return 5;
    }
}