lyx_mirror/src/support/lyxsum.cpp
Abdelrazak Younes 6d24433cc5 cosmetics.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@21902 a592a061-630c-0410-9148-cb99ea01b6c8
2007-12-02 08:09:16 +00:00

143 lines
3.0 KiB
C++

/**
* \file lyxsum.cpp
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Lars Gullik Bjønnes
*
* Full author contact details are available in file CREDITS.
*/
#include <config.h>
#include "support/lyxlib.h"
#include "support/debug.h"
#include "support/FileName.h"
#include <boost/crc.hpp>
#include <algorithm>
#include <iomanip>
using std::endl;
using std::string;
// OK, this is ugly, but it is the only workaround I found to compile
// with gcc (any version) on a system which uses a non-GNU toolchain.
// The problem is that gcc uses a weak symbol for a particular
// instantiation and that the system linker usually does not
// understand those weak symbols (seen on HP-UX, tru64, AIX and
// others). Thus we force an explicit instanciation of this particular
// template (JMarc)
template struct boost::detail::crc_table_t<32, 0x04C11DB7, true>;
// Various implementations of lyx::sum(), depending on what methods
// are available. Order is faster to slowest.
#if defined(HAVE_MMAP) && defined(HAVE_MUNMAP)
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <sys/mman.h>
namespace lyx {
namespace support {
unsigned long sum(char const * file)
{
//LYXERR(Debug::FILES, "lyx::sum() using mmap (lightning fast)");
int fd = open(file, O_RDONLY);
if (!fd)
return 0;
struct stat info;
fstat(fd, &info);
void * mm = mmap(0, info.st_size, PROT_READ,
MAP_PRIVATE, fd, 0);
// Some platforms have the wrong type for MAP_FAILED (compaq cxx).
if (mm == reinterpret_cast<void*>(MAP_FAILED)) {
close(fd);
return 0;
}
char * beg = static_cast<char*>(mm);
char * end = beg + info.st_size;
boost::crc_32_type crc;
crc.process_block(beg, end);
unsigned long result = crc.checksum();
munmap(mm, info.st_size);
close(fd);
return result;
}
} // namespace support
} // namespace lyx
#else // No mmap
#include <fstream>
#include <iterator>
namespace {
template<typename InputIterator>
inline
unsigned long do_crc(InputIterator first, InputIterator last)
{
boost::crc_32_type crc;
crc = std::for_each(first, last, crc);
return crc.checksum();
}
} // namespace anon
namespace lyx {
namespace support {
using std::ifstream;
using std::istreambuf_iterator;
using std::istream_iterator;
using std::ios;
using std::ios_base;
unsigned long sum(char const * file)
{
ifstream ifs(file, ios_base::in | ios_base::binary);
if (!ifs)
return 0;
#if HAVE_DECL_ISTREAMBUF_ITERATOR
//LYXERR(Debug::FILES, "lyx::sum() using istreambuf_iterator (fast)");
istreambuf_iterator<char> beg(ifs);
istreambuf_iterator<char> end;
#else
//LYXERR(Debug::FILES, "lyx::sum() using istream_iterator (slow as a snail)");
ifs.unsetf(ios::skipws);
istream_iterator<char> beg(ifs);
istream_iterator<char> end;
#endif
return do_crc(beg,end);
}
} // namespace support
} // namespace lyx
#endif // mmap