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/*
	WARNING: This file was generated by dkct.
	Changes you make here will be lost if dkct is run again!
	You should modify the original source and run dkct on it.
	Original source: dk4lzwe.ctr
*/

/*
Copyright (C) 2016-2017, Dirk Krause

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above opyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of the author nor the names of contributors may be used
  to endorse or promote products derived from this software without specific
  prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef DK4LZWE_H_INCLUDED
/** Avoid multiple inclusions. */
#define DK4LZWE_H_INCLUDED 1


#line 8 "dk4lzwe.ctr"

/**	@file	dk4lzwe.h	LZW encoder to produce PS level 2 output.

- The unit length (input data length) is 8 bits.
- Code 256 is used for table cleanup, 257 is the end of data marker.
- EarlyChange is in use: the number of bits per code is increased after
  creating table entries for codes 511, 1023 and 2047.
- Table entries are created for codes up to 4093. Instead of generating
  an entry for 4094, the table is cleared.
*/

#ifndef DK4ERROR_H_INCLUDED
#include <dk4error.h>
#endif

#ifndef	DK4BITSH_H_INCLUDED
#include <dk4bitsh.h>
#endif



/**	Table size.
	The table must be large enough to keep 4096 entries. Adding
	25 percent size significantly decreases the number of lookups.
	A prime number is required to ensure traversal of the entire
	table if necessary.
*/
enum {
	LZW_TABLE_SIZE = 5147	/**< Size of LZW compression table. */
};



/**	One table entry for LZW compression.
*/
typedef struct {
	unsigned short	os;		/**< Current (old) state or code. */
	unsigned short	ns;		/**< New state after applying input. */
	unsigned char	in;		/**< Input byte. */
} dk4_lzw_cell_t;



/**	LZW encoder structure.
*/
typedef struct {
	unsigned char	 ob[8];	/**< Output buffer. */
	dk4_bit_shift_t	 bs;	/**< Bit shifter. */
	dk4_lzw_cell_t	*p_tbl;	/**< Pointer to dynamically allocated table. */
	size_t			 obu;	/**< Used bytes in output buffer. */
	int				 mret;	/**< Flag: Must retrieve output data. */
	int				 hst;	/**< Flag: Have internal state. */
	unsigned short	 bits;	/**< Number of bits to use for output. */
	unsigned short	 cs;	/**< Current state. */
	unsigned short	 ns;	/**< Next state for new table entry. */
} dk4_lzwe_t;

#ifdef	__cplusplus
extern "C" {
#endif


/**	Initialize LZW encoder, allocate memory for resources.
	@param	lzwptr	Encoder to initialize.
	@param	erp		Error report, may be NULL.
	@return	1 on success, 0 on error.

	Error codes:
	- DK4_E_INVALID_ARGUMENTS<br>
	  if lzwptr is NULL,
	- DK4_E_MATH_OVERFLOW<br>
	  on numeric overflow when calculating the
	  product of elsize and nelem,
	- DK4_E_MEMORY_ALLOCATION_FAILED<br>
	  with mem.elsize and mem.nelem
	  set if there is not enough memory available,
	- DK4_E_BUG<br>
	  if the dk4bit_shift_add() call indicates an error
	  (should not happen as we provide a valid address to the function),
	- DK4_E_BUFFER_TOO_SMALL<br>
	  if the output buffer is already full. Typically this means
	  that output was not retrieved as expected by the library.
*/

int
dk4lzwe_init(
	dk4_lzwe_t	*lzwptr,
	dk4_er_t	*erp
);


/**	Add one byte to the encoder.
	@param	lzwptr	Encoder to use.
	@param	uc		Byte to add.
	@param	erp		Error report, may be NULL.
	@return	Operation result, one from:
	- DK4_EDSTM_ACCEPT<br>
	  if the input byte was successfully stored in the internal data
	  structures without completing a run. No further action
	  necessary.
	- DK4_EDSTM_FINISHED<br>
	  if output was created. Use dk4lzwe_output() to obtain the
	  output data.
	- DK4_EDSTM_ERROR<br>
	  if an error occured.
*/

int
dk4lzwe_add(
	dk4_lzwe_t		*lzwptr,
	unsigned char	 uc,
	dk4_er_t		*erp
);


/**	Finish encoded data stream, flush internal state and bits from
	the bit shifter to output buffer and release dynamic memory.
	@param	lzwptr	Encoder to use.
	@param	erp		Error report, may be NULL.
	@return	Operation result, one from:
	- DK4_EDSTM_ACCEPT<br>
	  if the input byte was successfully stored in the internal data
	  structures without completing a run. No further action
	  necessary.
	- DK4_EDSTM_FINISHED<br>
	  if output was created. Use dk4lzwe_output() to obtain the
	  output data.
	- DK4_EDSTM_ERROR<br>
	  if an error occured.
	
	Error codes:
	- DK4_E_INVALID_ARGUMENTS<br>
	  if lzwptr is NULL or lzwptr->s_tbl or lzwptr->i_tbl is NULL,
	- DK4_E_BUG<br>
	  if the dk4bit_shift_add() call indicates an error
	  (should not happen as we provide a valid address to the function),
	- DK4_E_BUFFER_TOO_SMALL<br>
	  if the output buffer is already full. Typically this means
	  that output was not retrieved as expected by the library.
*/

int
dk4lzwe_finish(
	dk4_lzwe_t		*lzwptr,
	dk4_er_t		*erp
);


/**	Retrieve output from encoder.
	@param	dptr	Address of result pointer.
	@param	szptr	Address of result size variable.
	@param	lzwptr	Encoder to use.
	@param	erp		Error report, may be NULL.
	@return	1 if data available, 0 otherwise.
*/

int
dk4lzwe_output(
	const unsigned char	**dptr,
	size_t				 *szptr,
	dk4_lzwe_t			 *lzwptr,
	dk4_er_t			 *erp
);


#ifdef	__cplusplus
}
#endif

/* vim: set ai sw=4 ts=4 : */

#endif