asterisk/channels/iax2/include/codec_pref.h

151 lines
5.4 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2014, Digium, Inc.
*
* Joshua Colp <jcolp@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*!
* \file
* \brief Media Format Bitfield Compatibility API
*
* \author Joshua Colp <jcolp@digium.com>
*/
#ifndef _IAX2_CODEC_PREF_H_
#define _IAX2_CODEC_PREF_H_
struct ast_format;
struct ast_codec;
struct ast_format_cap;
#define IAX2_CODEC_PREF_SIZE 64
struct iax2_codec_pref {
/*! Array is ordered by preference. Contains the iax2_supported_formats[] index + 1. */
char order[IAX2_CODEC_PREF_SIZE];
/*! Framing size of the codec */
unsigned int framing[IAX2_CODEC_PREF_SIZE];
};
/*!
* \brief Convert an iax2_codec_pref order value into a format bitfield
*
* \param order_value value being converted
*
* \return the bitfield value of the order_value format
*/
uint64_t iax2_codec_pref_order_value_to_format_bitfield(int order_value);
/*!
* \brief Convert a format bitfield into an iax2_codec_pref order value
*
* \param bitfield value being converted
*
* \return the iax2_codec_pref order value of the most significant format
* in the bitfield.
*
* \note This is really meant to be used on single format bitfields.
* It will work with multiformat bitfields, but it can only return the
* index of the most significant one if that is the case.
*/
int iax2_codec_pref_format_bitfield_to_order_value(uint64_t bitfield);
/*!
* \brief Codec located at a particular place in the preference index.
* \param pref preference structure to get the codec out of
* \param index to retrieve from
* \param result ast_format structure to store the index value in
* \return pointer to input ast_format on success, NULL on failure
*/
struct ast_format *iax2_codec_pref_index(struct iax2_codec_pref *pref, int index, struct ast_format **result);
/*!
* \brief Convert a preference structure to a capabilities structure.
*
* \param pref Formats in preference order to build the capabilities.
* \param cap Capabilities structure to place formats into
*
* \retval 0 on success.
* \retval -1 on error.
*
* \note If failure occurs the capabilities structure may contain a partial set of formats
*/
int iax2_codec_pref_to_cap(struct iax2_codec_pref *pref, struct ast_format_cap *cap);
/*!
* \brief Convert a bitfield to a format capabilities structure in the "best" order.
*
* \param bitfield The bitfield for the media formats
* \param prefs Format preference order to use as a guide. (May be NULL)
* \param cap Capabilities structure to place formats into
*
* \retval 0 on success.
* \retval -1 on error.
*
* \note If failure occurs the capabilities structure may contain a partial set of formats
*/
int iax2_codec_pref_best_bitfield2cap(uint64_t bitfield, struct iax2_codec_pref *prefs, struct ast_format_cap *cap);
/*! \brief Removes format from the pref list that aren't in the bitfield */
void iax2_codec_pref_remove_missing(struct iax2_codec_pref *pref, uint64_t bitfield);
/*!
* \brief Dump audio codec preference list into a string
*
* \param pref preference structure to dump string representation of order for
* \param buf character buffer to put string into
* \param size size of the character buffer
*
* \return -1 on error. Otherwise returns the remaining spaaaaaace in the buffer.
*
* \note Format is (codec1|codec2|codec3|...) -- if the list is too long for the
* size of the buffer, codecs will be written until they exceed the length
* remaining in which case the list will be closed with '...)' after the last
* writable codec.
*/
int iax2_codec_pref_string(struct iax2_codec_pref *pref, char *buf, size_t size);
/*! \brief Append a audio codec to a preference list, removing it first if it was already there
*/
void iax2_codec_pref_append(struct iax2_codec_pref *pref, struct ast_format *format, unsigned int framing);
/*! \brief Prepend an audio codec to a preference list, removing it first if it was already there
*/
void iax2_codec_pref_prepend(struct iax2_codec_pref *pref, struct ast_format *format, unsigned int framing,
int only_if_existing);
/*! \brief Shift an audio codec preference list up or down 65 bytes so that it becomes an ASCII string
* \note Due to a misunderstanding in how codec preferences are stored, this
* list starts at 'B', not 'A'. For backwards compatibility reasons, this
* cannot change.
* \param pref A codec preference list structure
* \param buf A string denoting codec preference, appropriate for use in line transmission
* \param size Size of \a buf
* \param right Boolean: if 0, convert from \a buf to \a pref; if 1, convert from \a pref to \a buf.
*/
void iax2_codec_pref_convert(struct iax2_codec_pref *pref, char *buf, size_t size, int right);
/*!
* \brief Create codec preference list from the given bitfield formats.
* \since 13.0.0
*
* \param pref Codec preference list to setup from the given bitfield.
* \param bitfield Format bitfield to guide preference list creation.
*
* \return Updated bitfield with any bits not mapped to a format cleared.
*/
uint64_t iax2_codec_pref_from_bitfield(struct iax2_codec_pref *pref, uint64_t bitfield);
#endif /* _IAX2_CODEC_PREF_H_ */