1 files changed, 112 insertions, 0 deletions
diff --git a/lib/pnmstream.cc b/lib/pnmstream.cc
new file mode 100644
index 0000000..0f4ee6b
--- /dev/null
+++ b/lib/pnmstream.cc
@@ -0,0 +1,112 @@
+//  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