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authorNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-07-13 02:16:54 +0200
committerNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-07-13 02:16:54 +0200
commit80399b01988dd002733248e0e2410b6a55be4576 (patch)
treee305d0fe1ad67695fba32c2b6d813026eb26c993
parent6a6e63de8f5f879b53e42fb70b769e991159798f (diff)
undelete
-rw-r--r--include/openbsc/v42bis.h147
-rw-r--r--include/openbsc/v42bis_private.h126
2 files changed, 273 insertions, 0 deletions
diff --git a/include/openbsc/v42bis.h b/include/openbsc/v42bis.h
new file mode 100644
index 00000000..607a58e5
--- /dev/null
+++ b/include/openbsc/v42bis.h
@@ -0,0 +1,147 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * v42bis.h
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2005, 2011 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*! \page v42bis_page V.42bis modem data compression
+\section v42bis_page_sec_1 What does it do?
+The v.42bis specification defines a data compression scheme, to work in
+conjunction with the error correction scheme defined in V.42.
+
+\section v42bis_page_sec_2 How does it work?
+*/
+
+#include <stdint.h>
+
+#if !defined(_SPANDSP_V42BIS_H_)
+#define _SPANDSP_V42BIS_H_
+
+#define SPAN_DECLARE(x) x
+
+#define V42BIS_MIN_STRING_SIZE 6
+#define V42BIS_MAX_STRING_SIZE 250
+#define V42BIS_MIN_DICTIONARY_SIZE 512
+#define V42BIS_MAX_BITS 12
+#define V42BIS_MAX_CODEWORDS 4096 /* 2^V42BIS_MAX_BITS */
+#define V42BIS_MAX_OUTPUT_LENGTH 1024
+
+enum
+{
+ V42BIS_P0_NEITHER_DIRECTION = 0,
+ V42BIS_P0_INITIATOR_RESPONDER,
+ V42BIS_P0_RESPONDER_INITIATOR,
+ V42BIS_P0_BOTH_DIRECTIONS
+};
+
+enum
+{
+ V42BIS_COMPRESSION_MODE_DYNAMIC = 0,
+ V42BIS_COMPRESSION_MODE_ALWAYS,
+ V42BIS_COMPRESSION_MODE_NEVER
+};
+
+typedef void (*put_msg_func_t)(void *user_data, const uint8_t *msg, int len);
+
+/*!
+ V.42bis compression/decompression descriptor. This defines the working state for a
+ single instance of V.42bis compress/decompression.
+*/
+typedef struct v42bis_state_s v42bis_state_t;
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+/*! Compress a block of octets.
+ \param s The V.42bis context.
+ \param buf The data to be compressed.
+ \param len The length of the data buffer.
+ \return 0 */
+SPAN_DECLARE(int) v42bis_compress(v42bis_state_t *s, const uint8_t buf[], int len);
+
+/*! Flush out any data remaining in a compression buffer.
+ \param s The V.42bis context.
+ \return 0 */
+SPAN_DECLARE(int) v42bis_compress_flush(v42bis_state_t *s);
+
+/*! Decompress a block of octets.
+ \param s The V.42bis context.
+ \param buf The data to be decompressed.
+ \param len The length of the data buffer.
+ \return 0 */
+SPAN_DECLARE(int) v42bis_decompress(v42bis_state_t *s, const uint8_t buf[], int len);
+
+/*! Flush out any data remaining in the decompression buffer.
+ \param s The V.42bis context.
+ \return 0 */
+SPAN_DECLARE(int) v42bis_decompress_flush(v42bis_state_t *s);
+
+/*! Set the compression mode.
+ \param s The V.42bis context.
+ \param mode One of the V.42bis compression modes -
+ V42BIS_COMPRESSION_MODE_DYNAMIC,
+ V42BIS_COMPRESSION_MODE_ALWAYS,
+ V42BIS_COMPRESSION_MODE_NEVER */
+SPAN_DECLARE(void) v42bis_compression_control(v42bis_state_t *s, int mode);
+
+/*! Initialise a V.42bis context.
+ \param s The V.42bis context.
+ \param negotiated_p0 The negotiated P0 parameter, from the V.42bis spec.
+ \param negotiated_p1 The negotiated P1 parameter, from the V.42bis spec.
+ \param negotiated_p2 The negotiated P2 parameter, from the V.42bis spec.
+ \param encode_handler Encode callback handler.
+ \param encode_user_data An opaque pointer passed to the encode callback handler.
+ \param max_encode_len The maximum length that should be passed to the encode handler.
+ \param decode_handler Decode callback handler.
+ \param decode_user_data An opaque pointer passed to the decode callback handler.
+ \param max_decode_len The maximum length that should be passed to the decode handler.
+ \return The V.42bis context. */
+SPAN_DECLARE(v42bis_state_t *) v42bis_init(const void *ctx,
+ v42bis_state_t *s,
+ int negotiated_p0,
+ int negotiated_p1,
+ int negotiated_p2,
+ put_msg_func_t encode_handler,
+ void *encode_user_data,
+ int max_encode_len,
+ put_msg_func_t decode_handler,
+ void *decode_user_data,
+ int max_decode_len);
+
+/*! Release a V.42bis context.
+ \param s The V.42bis context.
+ \return 0 if OK */
+SPAN_DECLARE(int) v42bis_release(v42bis_state_t *s);
+
+/*! Free a V.42bis context.
+ \param s The V.42bis context.
+ \return 0 if OK */
+SPAN_DECLARE(int) v42bis_free(v42bis_state_t *s);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/
diff --git a/include/openbsc/v42bis_private.h b/include/openbsc/v42bis_private.h
new file mode 100644
index 00000000..daa5ea31
--- /dev/null
+++ b/include/openbsc/v42bis_private.h
@@ -0,0 +1,126 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * private/v42bis.h
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2005 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#if !defined(_SPANDSP_PRIVATE_V42BIS_H_)
+#define _SPANDSP_PRIVATE_V42BIS_H_
+
+/*!
+ V.42bis dictionary node.
+ Note that 0 is not a valid node to point to (0 is always a control code), so 0 is used
+ as a "no such value" marker in this structure.
+*/
+typedef struct
+{
+ /*! \brief The value of the octet represented by the current dictionary node */
+ uint8_t node_octet;
+ /*! \brief The parent of this node */
+ uint16_t parent;
+ /*! \brief The first child of this node */
+ uint16_t child;
+ /*! \brief The next node at the same depth */
+ uint16_t next;
+} v42bis_dict_node_t;
+
+/*!
+ V.42bis compression or decompression. This defines the working state for a single instance
+ of V.42bis compression or decompression.
+*/
+typedef struct
+{
+ /*! \brief Compression enabled. */
+ int v42bis_parm_p0;
+ /*! \brief Compression mode. */
+ int compression_mode;
+ /*! \brief Callback function to handle output data. */
+ put_msg_func_t handler;
+ /*! \brief An opaque pointer passed in calls to the data handler. */
+ void *user_data;
+ /*! \brief The maximum amount to be passed to the data handler. */
+ int max_output_len;
+
+ /*! \brief TRUE if we are in transparent (i.e. uncompressable) mode */
+ int transparent;
+ /*! \brief Next empty dictionary entry */
+ uint16_t v42bis_parm_c1;
+ /*! \brief Current codeword size */
+ uint16_t v42bis_parm_c2;
+ /*! \brief Threshold for codeword size change */
+ uint16_t v42bis_parm_c3;
+ /*! \brief The current update point in the dictionary */
+ uint16_t update_at;
+ /*! \brief The last entry matched in the dictionary */
+ uint16_t last_matched;
+ /*! \brief The last entry added to the dictionary */
+ uint16_t last_added;
+ /*! \brief Total number of codewords in the dictionary */
+ int v42bis_parm_n2;
+ /*! \brief Maximum permitted string length */
+ int v42bis_parm_n7;
+ /*! \brief The dictionary */
+ v42bis_dict_node_t dict[V42BIS_MAX_CODEWORDS];
+
+ /*! \brief The octet string in progress */
+ uint8_t string[V42BIS_MAX_STRING_SIZE];
+ /*! \brief The current length of the octet string in progress */
+ int string_length;
+ /*! \brief The amount of the octet string in progress which has already
+ been flushed out of the buffer */
+ int flushed_length;
+
+ /*! \brief Compression performance metric */
+ uint16_t compression_performance;
+
+ /*! \brief Outgoing bit buffer (compression), or incoming bit buffer (decompression) */
+ uint32_t bit_buffer;
+ /*! \brief Outgoing bit count (compression), or incoming bit count (decompression) */
+ int bit_count;
+
+ /*! \brief The output composition buffer */
+ uint8_t output_buf[V42BIS_MAX_OUTPUT_LENGTH];
+ /*! \brief The length of the contents of the output composition buffer */
+ int output_octet_count;
+
+ /*! \brief The current value of the escape code */
+ uint8_t escape_code;
+ /*! \brief TRUE if we just hit an escape code, and are waiting for the following octet */
+ int escaped;
+} v42bis_comp_state_t;
+
+/*!
+ V.42bis compression/decompression descriptor. This defines the working state for a
+ single instance of V.42bis compress/decompression.
+*/
+struct v42bis_state_s
+{
+ /*! \brief Compression state. */
+ v42bis_comp_state_t compress;
+ /*! \brief Decompression state. */
+ v42bis_comp_state_t decompress;
+
+ /*! \brief Error and flow logging control */
+};
+
+#endif
+/*- End of file ------------------------------------------------------------*/