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#define XERR
#include "mapbase.ih"
bool MapBase::map(int protection) // PROT_READ, PROT_WRITE or both
{
if (not d_writing and d_absPos >= d_orgSize) // nothing to map at EOF
return false; // when reading
unmap();
// WIP:
if (not d_absolute)
d_absPos = d_offset + pptr() - pbase();
d_offset = d_absPos / s_pageSize * s_pageSize; // d_offset <= d_absPos
if (d_writing)
writingMapLength();
else if (not readingMapLength()) // set the reading mapLength
return true; // no length: don't mmap
//xerr("absPos = " << d_absPos << ", offset " << d_offset <<\X=========
//", length: " << d_mapLength << ", enlarged size: " << d_enlargedSize);
int fd = open(d_fname.c_str(),
protection == PROT_READ ? O_RDONLY : O_RDWR);
if (fd == -1) // file can't be opened
throw Exception{} << "can't open " << d_fname;
// d_mapLength may exceed the file's size
d_cp = static_cast<char *>( // mmap the required buffer
mmap(0, d_mapLength, protection, MAP_SHARED, fd, d_offset)
);
close(fd);
if (d_cp == MAP_FAILED) // mapping failed
throw Exception{} << "mmap for " << d_fname << " failed";
d_mMapped = true;
// no set{pg} because they're called by {io}mapbuf
return true;
}
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