libs/regex/example/jgrep/jgrep.cpp
/*
*
* Copyright (c) 1998-2002
* Dr John Maddock
*
* Use, modification and distribution are subject to 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)
*
*/
/*
* FILE jgrep.cpp
* VERSION see <boost/version.hpp>
*/
#include <stdio.h>
#include <algorithm>
#include <boost/regex.hpp>
#ifdef JM_OLD_IOSTREAM
#include <iostream.h>
#else
#include <iostream>
using std::cout;
using std::cin;
using std::cerr;
using std::endl;
#endif
#ifdef __BORLANDC__
# pragma hrdstop
#endif
#ifdef BOOST_REGEX_V3
#include <boost/regex/v3/fileiter.hpp>
#else
#include <boost/regex/v4/fileiter.hpp>
#endif
#include "jgrep.h"
#ifndef BOOST_REGEX_NO_FILEITER
//
// class ogrep_predicate
// outputs the results of regex_grep to screen:
template <class iterator, class Allocator >
class ogrep_predicate
{
unsigned int& lines;
const char* filename;
unsigned int last_line;
iterator end_of_storage, last_line_start;
public:
ogrep_predicate(unsigned int& i, const char* p, iterator start, iterator end) : lines(i), filename(p), last_line(-1), end_of_storage(end), last_line_start(start) {}
ogrep_predicate(const ogrep_predicate& o) : lines(o.lines), filename(o.filename), last_line(o.last_line), end_of_storage(o.end_of_storage), last_line_start(o.last_line_start) {}
bool operator () (const boost::match_results<iterator, Allocator>& i);
};
// ideally we'd ignor the allocator type and use a template member function
// to deel with the allocator type passed to regex_grep, unfortunately most
// compilers don't support this feature yet, so we'll have to be sure that
// the allocator passed to instances of this class match that used in our
// regular expression classes.
template <class iterator, class Allocator>
bool ogrep_predicate<iterator, Allocator>::operator()(const boost::match_results<iterator, Allocator>& i)
{
// if we haven't printed the filename yet, then do it now:
if(last_line == (unsigned int)-1)
{
cout << "File " << filename << ":" << endl;
last_line = 0;
}
// calculate which line we are on, by adding the number of newlines
// we've skipped in the last search:
unsigned int current_line = last_line + std::count(last_line_start, end_of_storage, '\n');
// if we haven't already printed this line out, then do it now:
if(last_line != current_line)
{
++lines;
last_line = current_line;
if(count_only == 0)
{
if(show_lines)
cout << current_line << "\t";
const char* nls = "\n";
iterator ptr = std::find_end(last_line_start, i[0].first, nls, nls+1);
++ptr;
iterator ptr2 = ptr;
while((ptr2 != end_of_storage) && (*ptr2 != '\n'))++ptr2;
while(ptr != ptr2)
{
cout.put(*ptr);
++ptr;
}
cout << endl;
}
}
// set the last line seen to the start of the current match:
last_line_start = i[0].first;
return true;
}
using namespace boost;
void process_grep(const char* file)
{
try{
mapfile f(file);
unsigned int count = 0;
ogrep_predicate<mapfile::iterator, boost::match_results<mapfile::iterator>::allocator_type> oi(count, file, f.begin(), f.end());
if(files_only)
{
bool ok;
boost::match_results<mapfile::iterator> m;
ok = regex_search(f.begin(), f.end(), m, e, match_not_dot_newline | match_not_dot_null);
if(ok)
cout << "File " << file << endl;
}
else
{
regex_grep(oi, f.begin(), f.end(), e, match_not_dot_newline | match_not_dot_null);
if(count)
{
if(verbose || count_only)
{
cout << count << " lines match" << endl;
return;
}
}
else if(verbose)
{
cout << "File " << file << "(" << f.size() << "bytes):" << endl << "0 lines match" << endl;
}
}
}
catch(const std::exception& e)
{
std::cerr << std::endl << e.what() << std::endl;
}
catch(...)
{
}
}
#endif