//C- -*- C++ -*-
//C- -------------------------------------------------------------------
//C- DjVuLibre-3.5
//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.
//C- Copyright (c) 2001 AT&T
//C-
//C- This software is subject to, and may be distributed under, the
//C- GNU General Public License, either Version 2 of the license,
//C- or (at your option) any later version. The license should have
//C- accompanied the software or you may obtain a copy of the license
//C- from the Free Software Foundation at http://www.fsf.org .
//C-
//C- This program is distributed in the hope that it will be useful,
//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//C- GNU General Public License for more details.
//C-
//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library from
//C- Lizardtech Software. Lizardtech Software has authorized us to
//C- replace the original DjVu(r) Reference Library notice by the following
//C- text (see doc/lizard2002.djvu and doc/lizardtech2007.djvu):
//C-
//C- ------------------------------------------------------------------
//C- | DjVu (r) Reference Library (v. 3.5)
//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
//C- | The DjVu Reference Library is protected by U.S. Pat. No.
//C- | 6,058,214 and patents pending.
//C- |
//C- | This software is subject to, and may be distributed under, the
//C- | GNU General Public License, either Version 2 of the license,
//C- | or (at your option) any later version. The license should have
//C- | accompanied the software or you may obtain a copy of the license
//C- | from the Free Software Foundation at http://www.fsf.org .
//C- |
//C- | The computer code originally released by LizardTech under this
//C- | license and unmodified by other parties is deemed "the LIZARDTECH
//C- | ORIGINAL CODE." Subject to any third party intellectual property
//C- | claims, LizardTech grants recipient a worldwide, royalty-free,
//C- | non-exclusive license to make, use, sell, or otherwise dispose of
//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the
//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU
//C- | General Public License. This grant only confers the right to
//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to
//C- | the extent such infringement is reasonably necessary to enable
//C- | recipient to make, have made, practice, sell, or otherwise dispose
//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to
//C- | any greater extent that may be necessary to utilize further
//C- | modifications or combinations.
//C- |
//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
//C- +------------------------------------------------------------------
#ifndef _IFFBYTESTREAM_H_
#define _IFFBYTESTREAM_H_
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#if NEED_GNUG_PRAGMAS
# pragma interface
#endif
/** @name IFFByteStream.h
Files #"IFFByteStream.h"# and #"IFFByteStream.cpp"# implement a parser for
files structured according the Electronic Arts ``EA IFF 85 Interchange
File Format''. IFF files are composed of a sequence of data {\em chunks}.
Each chunk is identified by a four character {\em chunk identifier}
describing the type of the data stored in the chunk. A few special chunk
identifiers, for instance #"FORM"#, are reserved for {\em composite
chunks} which themselves contain a sequence of data chunks. This
conventions effectively provides IFF files with a convenient hierarchical
structure. Composite chunks are further identified by a secondary chunk
identifier.
We found convenient to define a {\em extended chunk identifier}. In the
case of a regular chunk, the extended chunk identifier is simply the
chunk identifier, as in #"PM44"#. In the case of a composite chunk, the
extended chunk identifier is composed by concatenating the main chunk
identifier, a colon, and the secondary chunk identifier, as in
#"FORM:DJVU"#.
Class \Ref{IFFByteStream} provides a way to read or write IFF structured
files. Member functions provide an easy mean to position the underlying
\Ref{ByteStream} at the beginning of each chunk and to read or write the
data until reaching the end of the chunk. The utility program
\Ref{djvuinfo} demonstrates how to use class #IFFByteStream#.
{\bf IFF Files and ZP-Coder} ---
Class #IFFByteStream# repositions the underlying ByteStream whenever a new
chunk is accessed. It is possible to code chunk data with the ZP-Coder
without worrying about the final file position. See class \Ref{ZPCodec}
for more details.
{\bf DjVu IFF Files} --- We had initially planned to exactly follow the
IFF specifications. Then we realized that certain versions of MSIE
recognize any IFF file as a Microsoft AIFF sound file and pop a message
box "Cannot play that sound". It appears that the structure of AIFF files
is entirely modeled after the IFF standard, with small variations
regarding the endianness of numbers and the padding rules. We eliminate
this problem by casting the octet protection spell. Our IFF files always
start with the four octets #0x41,0x54,0x26,0x54# followed by the fully
conformant IFF byte stream. Class #IFFByteStream# silently skips these
four octets when it encounters them.
{\bf References} --- EA IFF 85 Interchange File Format specification:\\
\URL{http://www.cica.indiana.edu/graphics/image_specs/ilbm.format.txt} or
\URL{http://www.tnt.uni-hannover.de/soft/compgraph/fileformats/docs/iff.pre}
@memo
IFF file parser.
@author
L\'eon Bottou <leonb@research.att.com>
// From: Leon Bottou, 1/31/2002
// This has been changed by Lizardtech to fit better
// with their re-implementation of ByteStreams.
*/
//@{
#include "DjVuGlobal.h"
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "GException.h"
#include "GString.h"
#include "ByteStream.h"
#ifdef HAVE_NAMESPACES
namespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode
}
#endif
#endif
/** ByteStream interface for an IFF file.
Class #IFFByteStream# augments the #ByteStream# interface with
functions for navigating from chunk to chunk. It works in relation
with a ByteStream specified at construction time.
{\bf Reading an IFF file} --- You can read an IFF file by constructing an
#IFFByteStream# object attached to the ByteStream containing the IFF file.
Calling function \Ref{get_chunk} positions the file pointer at the
beginning of the first chunk. You can then use \Ref{ByteStream::read} to
access the chunk data. Function #read# will return #0# if you attempt to
read past the end of the chunk, just as if you were trying to read past
the end of a file. You can at any time call function \Ref{close_chunk} to
terminate reading data in this chunk. The following chunks can be
accessed by calling #get_chunk# and #close_chunk# repeatedly until you
reach the end of the file. Function #read# is not very useful when
accessing a composite chunk. You can instead make nested calls to
functions #get_chunk# and #close_chunk# in order to access the chunks
located inside the composite chunk.
{\bf Writing an IFF file} --- You can write an IFF file by constructing an
#IFFByteStream# object attached to the seekable ByteStream object that
will contain the IFF file. Calling function \Ref{put_chunk} creates a
first chunk header and positions the file pointer at the beginning of the
chunk. You can then use \Ref{ByteStream::write} to store the chunk data.
Calling function \Ref{close_chunk} terminates the current chunk. You can
append more chunks by calling #put_chunk# and #close_chunk# repeatedly.
Function #write# is not very useful for writing a composite chunk. You
can instead make nested calls to function #put_chunk# and #close_chunk# in
order to create chunks located inside the composite chunk.
Writing an IFF file requires a seekable ByteStream (see
\Ref{ByteStream::is_seekable}). This is not much of a problem because you
can always create the IFF file into a \Ref{MemoryByteStream} and then use
\Ref{ByteStream::copy} to transfer the IFF file into a non seekable
ByteStream. */
class DJVUAPI IFFByteStream : protected ByteStream::Wrapper
{
protected:
IFFByteStream(const GP<ByteStream> &bs, const int pos);
public:
/** Constructs an IFFByteStream object attached to ByteStream #bs#.
Any ByteStream can be used when reading an IFF file. Writing
an IFF file however requires a seekable ByteStream. */
static GP<IFFByteStream> create(const GP<ByteStream> &bs);
// --- BYTESTREAM INTERFACE
~IFFByteStream();
virtual size_t read(void *buffer, size_t size);
virtual size_t write(const void *buffer, size_t size);
virtual long tell(void) const;
// -- NAVIGATING CHUNKS
/** Enters a chunk for reading. Function #get_chunk# returns zero when the
last chunk has already been accessed. Otherwise it parses a chunk
header, positions the IFFByteStream at the beginning of the chunk data,
stores the extended chunk identifier into string #chkid#, and returns
the non zero chunk size. The file offset of the chunk data may be
retrieved using function #tell#. The chunk data can then be read using
function #read# until reaching the end of the chunk. Advanced users may
supply two pointers to integer variables using arguments #rawoffsetptr#
and #rawsizeptr#. These variables will be overwritten with the offset
and the length of the file segment containing both the chunk header and
the chunk data. */
int get_chunk(GUTF8String &chkid, int *rawoffsetptr=0, int *rawsizeptr=0);
/** Enters a chunk for writing. Function #put_chunk# prepares a chunk
header and positions the IFFByteStream at the beginning of the chunk
data. Argument #chkid# defines a extended chunk identifier for this
chunk. The chunk data can then be written using function #write#. The
chunk is terminated by a matching call to function #close_chunk#. When
#insertmagic# is non zero, function #put_chunk# inserts the bytes:
0x41, 0x54, 0x26, 0x54 before the chunk header, as discussed in
\Ref{IFFByteStream.h}. */
void put_chunk(const char *chkid, int insertmagic=0);
/** Leaves the current chunk. This function leaves the chunk previously
entered by a matching call to #get_chunk# and #put_chunk#. The
IFFByteStream is then ready to process the next chunk at the same
hierarchical level. */
void close_chunk();
/** This is identical to the above, plus it adds a seek to the start of
the next chunk. This way we catch EOF errors with the current chunk.*/
void seek_close_chunk();
/** Returns true when it is legal to call #read# or #write#. */
int ready();
/** Returns true when the current chunk is a composite chunk. */
int composite();
/** Returns the current chunk identifier of the current chunk. String
#chkid# is overwritten with the {\em extended chunk identifier} of the
current chunk. The extended chunk identifier of a regular chunk is
simply the chunk identifier, as in #"PM44"#. The extended chunk
identifier of a composite chunk is the concatenation of the chunk
identifier, of a semicolon #":"#, and of the secondary chunk identifier,
as in #"FORM:DJVU"#. */
void short_id(GUTF8String &chkid);
/** Returns the qualified chunk identifier of the current chunk. String
#chkid# is overwritten with the {\em qualified chunk identifier} of the
current chunk. The qualified chunk identifier of a composite chunk is
equal to the extended chunk identifier. The qualified chunk identifier
of a regular chunk is composed by concatenating the secondary chunk
identifier of the closest #"FORM"# or #"PROP"# composite chunk
containing the current chunk, a dot #"."#, and the current chunk
identifier, as in #"DJVU.INFO"#. According to the EA IFF 85 identifier
scoping rules, the qualified chunk identifier uniquely defines how the
chunk data should be interpreted. */
void full_id(GUTF8String &chkid);
/** Checks a potential chunk identifier. This function categorizes the
chunk identifier formed by the first four characters of string #chkid#.
It returns #0# if this is a legal identifier for a regular chunk. It
returns #+1# if this is a reserved composite chunk identifier. It
returns #-1# if this is an illegal or otherwise reserved identifier
which should not be used. */
static int check_id(const char *id);
GP<ByteStream> get_bytestream(void) {return this;}
/** Copy data from another ByteStream. A maximum of #size# bytes are read
from the ByteStream #bsfrom# and are written to the ByteStream #*this#
at the current position. Less than #size# bytes may be written if an
end-of-file mark is reached on #bsfrom#. This function returns the
total number of bytes copied. Setting argument #size# to zero (the
default value) has a special meaning: the copying process will continue
until reaching the end-of-file mark on ByteStream #bsfrom#, regardless
of the number of bytes transferred. */
size_t copy(ByteStream &bsfrom, size_t size=0)
{ return get_bytestream()->copy(bsfrom,size); }
/** Flushes all buffers in the ByteStream. Calling this function
guarantees that pending data have been actually written (i.e. passed to
the operating system). Class #ByteStream# provides a default
implementation which does nothing. */
virtual void flush(void)
{ ByteStream::Wrapper::flush(); }
/** This is a simple compare method. The IFFByteStream may be read for
the sake of the comparison. Since IFFByteStreams are non-seekable,
the stream is not valid for use after comparing, regardless of the
result. */
bool compare(IFFByteStream &iff);
/** #has_magic_att# is true if the stream has
the DjVu magic 'AT&T' marker. */
bool has_magic_att;
/** #has_magic_sdjv# is true if the stream has
the Celartem magic 'SDJV' marker. */
bool has_magic_sdjv;
private:
// private datatype
struct IFFContext
{
IFFContext *next;
long offStart;
long offEnd;
char idOne[4];
char idTwo[4];
char bComposite;
};
// Implementation
IFFContext *ctx;
long offset;
long seekto;
int dir;
// Cancel C++ default stuff
IFFByteStream(const IFFByteStream &);
IFFByteStream & operator=(const IFFByteStream &);
static GP<IFFByteStream> create(ByteStream *bs);
};
//@}
#ifdef HAVE_NAMESPACES
}
# ifndef NOT_USING_DJVU_NAMESPACE
using namespace DJVU;
# endif
#endif
#endif