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// pnmstream.cc -- image streams producing PNM files
// Copyright (C) 2008 SEIKO EPSON CORPORATION
//
// This file is part of the 'iscan' program.
//
// The 'iscan' program is free-ish software.
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation;
// either version 2 of the License or at your option any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of FITNESS
// FOR A PARTICULAR PURPOSE or MERCHANTABILITY.
// See the GNU General Public License for more details.
//
// You should have received a verbatim copy of the GNU General Public
// License along with this program; if not, write to:
//
// Free Software Foundation, Inc.
// 59 Temple Place, Suite 330
// Boston, MA 02111-1307 USA
//
// As a special exception, the copyright holders give permission
// to link the code of this program with the esmod library and
// distribute linked combinations including the two. You must obey
// the GNU General Public License in all respects for all of the
// code used other then esmod.
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "pnmstream.hh"
#include <ios>
namespace iscan
{
pnmstream::pnmstream (FILE *fp, const string& name)
: _stream (fp), _header (false)
{
if (!_stream) throw std::invalid_argument ("invalid file handle");
}
pnmstream::~pnmstream (void)
{
fflush (_stream);
}
basic_imgstream&
pnmstream::write (const byte_type *line, size_type n)
{
if (!line || 0 == n) return *this;
if (!_header)
{
write_header ();
}
size_t rv = fwrite (line, sizeof (byte_type), n, _stream);
if (n != rv) throw std::ios_base::failure ("write error");
return *this;
}
bool
pnmstream::is_usable (void)
{
return true;
}
basic_imgstream&
pnmstream::write_header (void)
{
check_consistency ();
string magic;
if (mono == _cspc) magic = "P4";
if (grey == _cspc) magic = "P5";
if (RGB == _cspc) magic = "P6";
int rv;
rv = fprintf (_stream, "%s\n%zd %zd\n", magic.c_str (), _h_sz, _v_sz);
if (0 > rv) throw std::ios_base::failure ("write error");
if ("P4" != magic)
{
rv = fprintf (_stream, "%d\n", (1 << _bits) - 1);
if (0 > rv) throw std::ios_base::failure ("write error");
}
_header = true;
return *this;
}
void
pnmstream::check_consistency (void) const
{
if (!(mono == _cspc || grey == _cspc || RGB == _cspc))
{
throw std::logic_error ("unsupported colour space");
}
if (_bits > 16)
{
throw std::logic_error ("maximum bit depth exceeded");
}
if (grey == _cspc || RGB == _cspc)
{
if (8 != _bits && 16 != _bits)
{
throw std::invalid_argument ("bit depth/colour space mismatch");
}
}
}
} // namespace iscan
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