remove NO_PEXTRA_STUFF

[lyx.git] / src / support / lyxsum.C

diff --git a/src/support/lyxsum.C b/src/support/lyxsum.C
index 930a7449d1fdf263b4db39b8afbb3d33bcf09b0e..213298cc0412cf7c4bc642359d6bee7ba69c65b1 100644 (file)
--- a/src/support/lyxsum.C
+++ b/src/support/lyxsum.C
@@ -1,6 +1,6 @@
 /* This file is part of
  * ======================================================
- * 
+ *
  *           LyX, The Document Processor
  *           Copyright 2001 The LyX Team.
  *
@@ -10,13 +10,67 @@
 
 #include <config.h>
 
-#include <fstream>
-#include <iterator>
+#include "support/lyxlib.h"
+#include "debug.h"
+
 #include <algorithm>
 #include <boost/crc.hpp>
 
-#include "support/lyxlib.h"
+using std::endl;
+
+// Various implementations of lyx::sum(), depending on what methods
+// are available. Order is faster to slowest.
+#if defined(HAVE_MMAP) && defined(HAVE_MUNMAP)
+
+// Make sure we get modern version of mmap and friends with void*,
+// not `compatibility' version with caddr_t.
+#define _POSIX_C_SOURCE 199506L
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+
+unsigned long lyx::sum(string const & file)
+{
+       lyxerr[Debug::FILES] << "lyx::sum() using mmap (lightning fast)"
+                            << endl;
+
+       int fd = open(file.c_str(), 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;
+}
+#else // No mmap
+
+#include <fstream>
+#include <iterator>
+
+using std::for_each;
 
 namespace {
 
@@ -25,29 +79,48 @@ inline
 unsigned long do_crc(InputIterator first, InputIterator last)
 {
        boost::crc_32_type crc;
-       crc = std::for_each(first, last, crc);
+       crc = for_each(first, last, crc);
        return crc.checksum();
 }
 
 } // namespace
 
+#if HAVE_DECL_ISTREAMBUF_ITERATOR
+using std::ifstream;
+using std::istreambuf_iterator;
 
-// And this would be the file interface.
 unsigned long lyx::sum(string const & file)
 {
-       std::ifstream ifs(file.c_str());
+       lyxerr[Debug::FILES] << "lyx::sum() using istreambuf_iterator (fast)"
+                            << endl;
+
+       ifstream ifs(file.c_str());
        if (!ifs) return 0;
-       
-#ifdef HAVE_DECL_ISTREAMBUF_ITERATOR
-       // This is a lot faster...
-       std::istreambuf_iterator<char> beg(ifs);
-       std::istreambuf_iterator<char> end;
+
+       istreambuf_iterator<char> beg(ifs);
+       istreambuf_iterator<char> end;
+
+       return do_crc(beg,end);
+}
 #else
-       // than this.
-       ifs.unsetf(std::ios::skipws);
-       std::istream_iterator<char> beg(ifs);
-       std::istream_iterator<char> end;
-#endif
 
-       return do_crc(beg, end);
+using std::istream_iterator;
+using std::ios;
+
+unsigned long lyx::sum(string const & file)
+{
+       lyxerr[Debug::FILES]
+               << "lyx::sum() using istream_iterator (slow as a snail)"
+               << endl;
+
+       ifstream ifs(file.c_str());
+       if (!ifs) return 0;
+
+       ifs.unsetf(ios::skipws);
+       istream_iterator<char> beg(ifs);
+       istream_iterator<char> end;
+
+       return do_crc(beg,end);
 }
+#endif
+#endif // mmap