spandsp 0.0.6
private/t4_t6_encode.h
00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * private/t4_t6_encode.h - definitions for T.4/T.6 fax compression
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2003 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU Lesser General Public License version 2.1,
00014  * as published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  */
00025 
00026 #if !defined(_SPANDSP_PRIVATE_T4_T6_ENCODE_H_)
00027 #define _SPANDSP_PRIVATE_T4_T6_ENCODE_H_
00028 
00029 /*!
00030     T.4 1D, T4 2D and T6 compressor state.
00031 */
00032 struct t4_t6_encode_state_s
00033 {
00034     /*! \brief The minimum number of encoded bits per row. This is a timing thing
00035                for hardware FAX machines. */
00036     int min_bits_per_row;
00037     /*! \brief The current maximum contiguous rows that may be 2D encoded. */
00038     int max_rows_to_next_1d_row;
00039 
00040     /*! \brief Number of rows left that can be 2D encoded, before a 1D encoded row
00041                must be used. */
00042     int rows_to_next_1d_row;
00043 
00044     /*! \brief The number of runs currently in the reference row. */
00045     int ref_steps;
00046 
00047     /*! \brief Pointer to the byte containing the next image bit to transmit. */
00048     int bit_pos;
00049     /*! \brief Pointer to the bit within the byte containing the next image bit to transmit. */
00050     int bit_ptr;
00051 
00052     /*! \brief Callback function to read a row of pixels from the image source. */
00053     t4_row_read_handler_t row_read_handler;
00054     /*! \brief Opaque pointer passed to row_read_handler. */
00055     void *row_read_user_data;
00056 };
00057 
00058 #endif
00059 /*- End of file ------------------------------------------------------------*/