/**
* relative seek
**/
::std::streampos seekoff(::std::streamoff off, ::std::ios_base::seekdir way, ::std::ios_base::openmode which)
{
// absolute seek
if ( way == ::std::ios_base::beg )
{
return seekpos(off,which);
}
// seek relative to current position
else if ( way == ::std::ios_base::cur )
{
if ( which == std::ios_base::in )
{
return seekpos(readpos + (gptr()-eback()),which);
}
else if ( which == std::ios_base::out )
{
return seekpos(writepos + (pptr()-pbase()),which);
}
else
{
return -1;
}
}
// seek relative to end of file
else if ( way == ::std::ios_base::end )
{
off_t const endoff = fd->getFileSize();
return seekpos(endoff+off,which);
}
else
{
return -1;
}
}
// seek
off_t doSeek(int64_t const p, int const whence)
{
off_t off = static_cast<off_t>(-1);
while ( (off=fd->lseek(p,whence)) == static_cast<off_t>(-1) )
{
int const error = errno;
switch ( error )
{
case EINTR:
case EAGAIN:
// try again
break;
default:
{
libmaus2::exception::LibMausException se;
se.getStream() << "PosixInputOutputStreamBuffer::doSeek(): seek() failed: " << strerror(error) << std::endl;
se.finish();
throw se;
}
}
}
return off;
}
size_t doRead(char * buffer, size_t count)
{
ssize_t r = -1;
while ( (r=fd->read(buffer,count)) < 0 )
{
int const error = errno;
switch ( error )
{
case EINTR:
case EAGAIN:
// try again
break;
default:
{
libmaus2::exception::LibMausException se;
se.getStream() << "PosixInputOutputStreamBuffer::doRead(): read() failed: " << strerror(error) << std::endl;
se.finish();
throw se;
}
}
}
return r;
}
void init(bool const repos)
{
// set empty buffer
setgchecked(buffer.end(), buffer.end(), buffer.end());
// seek
if ( repos )
fd->lseek(symsread,SEEK_SET);
}
MemoryInputStreamBuffer(
std::string const & rfn,
int64_t const rblocksize,
uint64_t const rputbackspace = 0
)
:
fd(doOpen(rfn)),
filesize(fd->getFileSize()),
blocksize((rblocksize < 0) ? getDefaultBlockSize() : rblocksize),
putbackspace(rputbackspace),
buffer(putbackspace + blocksize,false),
symsread(0)
{
init(false);
}
// write buffer contents
void doSync()
{
uint64_t n = pptr()-pbase();
pbump(-n);
char * p = pbase();
while ( n )
{
ssize_t const w = fd->write(p,n);
if ( w < 0 )
{
int const error = errno;
switch ( error )
{
case EINTR:
case EAGAIN:
break;
default:
{
libmaus2::exception::LibMausException se;
se.getStream() << "PosixInputOutputStreamBuffer::doSync(): write() failed: " << strerror(error) << std::endl;
se.finish();
throw se;
}
}
}
else
{
assert ( w <= static_cast<int64_t>(n) );
n -= w;
writepos += w;
}
}
assert ( ! n );
}
int_type underflow()
{
// if there is still data, then return it
if ( gptr() < egptr() )
return static_cast<int_type>(*uptr());
assert ( gptr() == egptr() );
// number of bytes for putback buffer
uint64_t const putbackcopy = std::min(
static_cast<uint64_t>(gptr() - eback()),
putbackspace
);
// copy bytes
std::copy(
gptr()-putbackcopy,
gptr(),
buffer.begin() + putbackspace - putbackcopy
);
// load data
uint64_t const uncompressedsize = fd->read(
buffer.begin()+putbackspace,
buffer.size()-putbackspace
);
// set buffer pointers
setgchecked(
buffer.begin()+putbackspace-putbackcopy,
buffer.begin()+putbackspace,
buffer.begin()+putbackspace+uncompressedsize);
symsread += uncompressedsize;
if ( uncompressedsize )
return static_cast<int_type>(*uptr());
else
return traits_type::eof();
}
