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comparison spandsp-0.0.6pre17/src/spandsp/private/t4_tx.h @ 4:26cd8f1ef0b1

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import spandsp-0.0.6pre17
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 15:50:58 +0200
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3:c6c5a16ce2f2 4:26cd8f1ef0b1
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * private/t4_tx.h - definitions for T.4 FAX transmit processing
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2003 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: t4_tx.h,v 1.7.2.4 2009/12/21 17:18:40 steveu Exp $
26 */
27
28 #if !defined(_SPANDSP_PRIVATE_T4_TX_H_)
29 #define _SPANDSP_PRIVATE_T4_TX_H_
30
31 typedef struct t4_t6_encode_state_s t4_t6_encode_state_t;
32
33 /*!
34 T.4 1D, T4 2D and T6 compressor state.
35 */
36 struct t4_t6_encode_state_s
37 {
38 /*! \brief The minimum number of encoded bits per row. This is a timing thing
39 for hardware FAX machines. */
40 int min_bits_per_row;
41 /*! \brief The current maximum contiguous rows that may be 2D encoded. */
42 int max_rows_to_next_1d_row;
43
44 /*! \brief The text which will be used in FAX page header. No text results
45 in no header line. */
46 const char *header_info;
47
48 /*! \brief Number of rows left that can be 2D encoded, before a 1D encoded row
49 must be used. */
50 int rows_to_next_1d_row;
51
52 /*! \brief The number of runs currently in the reference row. */
53 int ref_steps;
54
55 /*! \brief Pointer to the byte containing the next image bit to transmit. */
56 int bit_pos;
57 /*! \brief Pointer to the bit within the byte containing the next image bit to transmit. */
58 int bit_ptr;
59
60 /*! \brief Callback function to read a row of pixels from the image source. */
61 t4_row_read_handler_t row_read_handler;
62 /*! \brief Opaque pointer passed to row_read_handler. */
63 void *row_read_user_data;
64 };
65
66 /*!
67 T.4 FAX compression/decompression descriptor. This defines the working state
68 for a single instance of a T.4 FAX compression or decompression channel.
69 */
70 struct t4_state_s
71 {
72 /*! \brief The same structure is used for T.4 transmit and receive. This variable
73 records which mode is in progress. */
74 int rx;
75
76 /*! \brief The type of compression used between the FAX machines. */
77 int line_encoding;
78
79 /*! \brief The time at which handling of the current page began. */
80 time_t page_start_time;
81
82 /*! \brief The size of the compressed image on the line side, in bits. */
83 int line_image_size;
84
85 /*! \brief The current number of bytes per row of uncompressed image data. */
86 int bytes_per_row;
87 /*! \brief The size of the image in the image buffer, in bytes. */
88 int image_size;
89 /*! \brief The current size of the image buffer. */
90 int image_buffer_size;
91 /*! \brief A point to the image buffer. */
92 uint8_t *image_buffer;
93
94 /*! \brief The number of pages transferred to date. */
95 int current_page;
96 /*! \brief Column-to-column (X) resolution in pixels per metre. */
97 int x_resolution;
98 /*! \brief Row-to-row (Y) resolution in pixels per metre. */
99 int y_resolution;
100 /*! \brief Width of the current page, in pixels. */
101 int image_width;
102 /*! \brief Length of the current page, in pixels. */
103 int image_length;
104 /*! \brief Current pixel row number. */
105 int row;
106
107 /*! \brief This variable is set if we are treating the current row as a 2D encoded
108 one. */
109 int row_is_2d;
110 /*! \brief The current length of the current row. */
111 int row_len;
112
113 /*! \brief Black and white run-lengths for the current row. */
114 uint32_t *cur_runs;
115 /*! \brief Black and white run-lengths for the reference row. */
116 uint32_t *ref_runs;
117 /*! \brief Pointer to the buffer for the current pixel row. */
118 uint8_t *row_buf;
119
120 /*! \brief Encoded data bits buffer. */
121 uint32_t tx_bitstream;
122 /*! \brief The number of bits currently in tx_bitstream. */
123 int tx_bits;
124
125 /*! \brief The current number of bits in the current encoded row. */
126 int row_bits;
127 /*! \brief The minimum bits in any row of the current page. For monitoring only. */
128 int min_row_bits;
129 /*! \brief The maximum bits in any row of the current page. For monitoring only. */
130 int max_row_bits;
131
132 /*! \brief Error and flow logging control */
133 logging_state_t logging;
134
135 /*! \brief All TIFF file specific state information for the T.4 context. */
136 t4_tiff_state_t tiff;
137 t4_t6_decode_state_t t4_t6_rx;
138 t4_t6_encode_state_t t4_t6_tx;
139 };
140
141 #endif
142 /*- End of file ------------------------------------------------------------*/

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