include/asterisk/frame.h

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * 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 Asterisk internal frame definitions.
 * \arg For an explanation of frames, see \ref Def_Frame
 * \arg Frames are send of Asterisk channels, see \ref Def_Channel
 */

#ifndef _ASTERISK_FRAME_H
#define _ASTERISK_FRAME_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include <sys/time.h>

#include "asterisk/format.h"
#include "asterisk/endian.h"
#include "asterisk/linkedlists.h"

/*!
 * \page Def_Frame AST Multimedia and signalling frames
 * \section Def_AstFrame What is an ast_frame ?
 * A frame of data read used to communicate between
 * between channels and applications.
 * Frames are divided into frame types and subclasses.
 *
 * \par Frame types
 * \arg \b VOICE: Voice data, subclass is codec (AST_FORMAT_*)
 * \arg \b VIDEO: Video data, subclass is codec (AST_FORMAT_*)
 * \arg \b DTMF: A DTMF digit, subclass is the digit
 * \arg \b IMAGE: Image transport, mostly used in IAX
 * \arg \b TEXT: Text messages and character by character (real time text)
 * \arg \b TEXT_DATA: Text messages in an ast_msg_data structure
 * \arg \b HTML: URL's and web pages
 * \arg \b MODEM: Modulated data encodings, such as T.38 and V.150
 * \arg \b IAX: Private frame type for the IAX protocol
 * \arg \b CNG: Comfort noice frames
 * \arg \b CONTROL:A control frame, subclass defined as AST_CONTROL_
 * \arg \b NULL: Empty, useless frame
 *
 * \par Files
 * \arg frame.h Definitions
 * \arg frame.c Function library
 * \arg \ref Def_Channel Asterisk channels
 * \section Def_ControlFrame Control Frames
 * Control frames send signalling information between channels
 * and devices. They are prefixed with AST_CONTROL_, like AST_CONTROL_FRAME_HANGUP
 * \arg \b HANGUP The other end has hungup
 * \arg \b RING Local ring
 * \arg \b RINGING The other end is ringing
 * \arg \b ANSWER The other end has answered
 * \arg \b BUSY Remote end is busy
 * \arg \b TAKEOFFHOOK Make it go off hook (what's "it" ? )
 * \arg \b OFFHOOK Line is off hook
 * \arg \b CONGESTION Congestion (circuit is busy, not available)
 * \arg \b FLASH Other end sends flash hook
 * \arg \b WINK Other end sends wink
 * \arg \b OPTION Send low-level option
 * \arg \b RADIO_KEY Key radio (see app_rpt.c)
 * \arg \b RADIO_UNKEY Un-key radio (see app_rpt.c)
 * \arg \b PROGRESS Other end indicates call progress
 * \arg \b PROCEEDING Indicates proceeding
 * \arg \b HOLD Call is placed on hold
 * \arg \b UNHOLD Call is back from hold
 * \arg \b VIDUPDATE Video update requested
 * \arg \b SRCUPDATE The source of media has changed (RTP marker bit must change)
 * \arg \b SRCCHANGE Media source has changed (RTP marker bit and SSRC must change)
 * \arg \b CONNECTED_LINE Connected line has changed
 * \arg \b REDIRECTING Call redirecting information has changed.
 */

/*!
 * \brief Frame types
 *
 * \note It is important that the values of each frame type are never changed,
 * because it will break backwards compatability with older versions.
 * This is because these constants are transmitted directly over IAX2.
 */
enum ast_frame_type {
 /*! DTMF end event, subclass is the digit */
 AST_FRAME_DTMF_END = 1,
 /*! Voice data, subclass is AST_FORMAT_* */
 AST_FRAME_VOICE,
 /*! Video frame, maybe?? :) */
 AST_FRAME_VIDEO,
 /*! A control frame, subclass is AST_CONTROL_* */
 AST_FRAME_CONTROL,
 /*! An empty, useless frame */
 AST_FRAME_NULL,
 /*! Inter Asterisk Exchange private frame type */
 AST_FRAME_IAX,
 /*! Text messages. The character data may not be zero-terminated, so
 * care should be taken when passing it to functions that expect a
 * zero-terminated string. The frame's datalen member should be used
 * as it indicates the actual number of bytes available. */
 AST_FRAME_TEXT,
 /*! Image Frames */
 AST_FRAME_IMAGE,
 /*! HTML Frame */
 AST_FRAME_HTML,
 /*! Comfort Noise frame (subclass is level of CNG in -dBov),
 body may include zero or more 8-bit quantization coefficients */
 AST_FRAME_CNG,
 /*! Modem-over-IP data streams */
 AST_FRAME_MODEM,
 /*! DTMF begin event, subclass is the digit */
 AST_FRAME_DTMF_BEGIN,
 /*! Internal bridge module action. */
 AST_FRAME_BRIDGE_ACTION,
 /*! Internal synchronous bridge module action.
 * Synchronous bridge actions may be queued onto bridge
 * channels, but they absolutely must not ever be written
 * directly into bridges.
 */
 AST_FRAME_BRIDGE_ACTION_SYNC,
 /*! RTCP feedback (the subclass will contain the payload type) */
 AST_FRAME_RTCP,
 /*! Text message in an ast_msg_data structure */
 AST_FRAME_TEXT_DATA,
};
#define AST_FRAME_DTMF AST_FRAME_DTMF_END

enum {
 /*! This frame contains valid timing information */
 AST_FRFLAG_HAS_TIMING_INFO = (1 << 0),
 /*! This frame has been requeued */
 AST_FRFLAG_REQUEUED = (1 << 1),
 /*! This frame contains a valid sequence number */
 AST_FRFLAG_HAS_SEQUENCE_NUMBER = (1 << 2),
};

struct ast_frame_subclass {
 /*! A frame specific code */
 int integer;
 union {
 /*! The asterisk media format */
 struct ast_format *format;
 /*! The asterisk stream topology */
 struct ast_stream_topology *topology;
 };
 /*! For video formats, an indication that a frame ended */
 unsigned int frame_ending;
};

/*! \brief Data structure associated with a single frame of data
 */
struct ast_frame {
 /*! Kind of frame */
 enum ast_frame_type frametype;
 /*! Subclass, frame dependent */
 struct ast_frame_subclass subclass;
 /*! Length of data */
 int datalen;
 /*! Number of samples in this frame */
 int samples;
 /*! Was the data malloc'd? i.e. should we free it when we discard the frame? */
 int mallocd;
 /*! The number of bytes allocated for a malloc'd frame header */
 size_t mallocd_hdr_len;
 /*! How many bytes exist _before_ "data" that can be used if needed */
 int offset;
 /*! Optional source of frame for debugging */
 const char *src;
 /*! Pointer to actual data */
 union { void *ptr; uint32_t uint32; char pad[8]; } data;
 /*! Global delivery time */
 struct timeval delivery;
 /*! For placing in a linked list */
 AST_LIST_ENTRY(ast_frame) frame_list;
 /*! Misc. frame flags */
 unsigned int flags;
 /*! Timestamp in milliseconds */
 long ts;
 /*! Length in milliseconds */
 long len;
 /*! Sequence number */
 int seqno;
 /*! Stream number the frame originated from */
 int stream_num;
};

/*!
 * Set the various field of a frame to point to a buffer.
 * Typically you set the base address of the buffer, the offset as
 * AST_FRIENDLY_OFFSET, and the datalen as the amount of bytes queued.
 * The remaining things (to be done manually) is set the number of
 * samples, which cannot be derived from the datalen unless you know
 * the number of bits per sample.
 */
#define AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen) \
 { \
 (fr)->data.ptr = (char *)_base + (_ofs); \
 (fr)->offset = (_ofs); \
 (fr)->datalen = (_datalen); \
 }

/*! Queueing a null frame is fairly common, so we declare a global null frame object
 for this purpose instead of having to declare one on the stack */
extern struct ast_frame ast_null_frame;

/*! \brief Offset into a frame's data buffer.
 *
 * By providing some "empty" space prior to the actual data of an ast_frame,
 * this gives any consumer of the frame ample space to prepend other necessary
 * information without having to create a new buffer.
 *
 * As an example, RTP can use the data from an ast_frame and simply prepend the
 * RTP header information into the space provided by AST_FRIENDLY_OFFSET instead
 * of having to create a new buffer with the necessary space allocated.
 */
#define AST_FRIENDLY_OFFSET 64
#define AST_MIN_OFFSET 32 /*! Make sure we keep at least this much handy */

/*! Need the header be free'd? */
#define AST_MALLOCD_HDR (1 << 0)
/*! Need the data be free'd? */
#define AST_MALLOCD_DATA (1 << 1)
/*! Need the source be free'd? (haha!) */
#define AST_MALLOCD_SRC (1 << 2)

/* MODEM subclasses */
/*! T.38 Fax-over-IP */
#define AST_MODEM_T38 1
/*! V.150 Modem-over-IP */
#define AST_MODEM_V150 2

/* HTML subclasses */
/*! Sending a URL */
#define AST_HTML_URL 1
/*! Data frame */
#define AST_HTML_DATA 2
/*! Beginning frame */
#define AST_HTML_BEGIN 4
/*! End frame */
#define AST_HTML_END 8
/*! Load is complete */
#define AST_HTML_LDCOMPLETE 16
/*! Peer is unable to support HTML */
#define AST_HTML_NOSUPPORT 17
/*! Send URL, and track */
#define AST_HTML_LINKURL 18
/*! No more HTML linkage */
#define AST_HTML_UNLINK 19
/*! Reject link request */
#define AST_HTML_LINKREJECT 20

/*!
 * \brief Internal control frame subtype field values.
 *
 * \warning
 * IAX2 sends these values out over the wire. To prevent future
 * incompatibilities, pick the next value in the enum from whatever
 * is on the current trunk. If you lose the merge race you need to
 * fix the previous branches to match what is on trunk. In addition
 * you need to change chan_iax2 to explicitly allow the control
 * frame over the wire if it makes sense for the frame to be passed
 * to another Asterisk instance.
 */
enum ast_control_frame_type {
 AST_CONTROL_HANGUP = 1, /*!< Other end has hungup */
 AST_CONTROL_RING = 2, /*!< Local ring */
 AST_CONTROL_RINGING = 3, /*!< Remote end is ringing */
 AST_CONTROL_ANSWER = 4, /*!< Remote end has answered */
 AST_CONTROL_BUSY = 5, /*!< Remote end is busy */
 AST_CONTROL_TAKEOFFHOOK = 6, /*!< Make it go off hook */
 AST_CONTROL_OFFHOOK = 7, /*!< Line is off hook */
 AST_CONTROL_CONGESTION = 8, /*!< Congestion (circuits busy) */
 AST_CONTROL_FLASH = 9, /*!< Flash hook */
 AST_CONTROL_WINK = 10, /*!< Wink */
 AST_CONTROL_OPTION = 11, /*!< Set a low-level option */
 AST_CONTROL_RADIO_KEY = 12, /*!< Key Radio */
 AST_CONTROL_RADIO_UNKEY = 13, /*!< Un-Key Radio */
 AST_CONTROL_PROGRESS = 14, /*!< Indicate PROGRESS */
 AST_CONTROL_PROCEEDING = 15, /*!< Indicate CALL PROCEEDING */
 AST_CONTROL_HOLD = 16, /*!< Indicate call is placed on hold */
 AST_CONTROL_UNHOLD = 17, /*!< Indicate call is left from hold */
 AST_CONTROL_VIDUPDATE = 18, /*!< Indicate video frame update */
 _XXX_AST_CONTROL_T38 = 19, /*!< T38 state change request/notification \deprecated This is no longer supported. Use AST_CONTROL_T38_PARAMETERS instead. */
 AST_CONTROL_SRCUPDATE = 20, /*!< Indicate source of media has changed */
 AST_CONTROL_TRANSFER = 21, /*!< Indicate status of a transfer request */
 AST_CONTROL_CONNECTED_LINE = 22,/*!< Indicate connected line has changed */
 AST_CONTROL_REDIRECTING = 23, /*!< Indicate redirecting id has changed */
 AST_CONTROL_T38_PARAMETERS = 24,/*!< T38 state change request/notification with parameters */
 AST_CONTROL_CC = 25, /*!< Indication that Call completion service is possible */
 AST_CONTROL_SRCCHANGE = 26, /*!< Media source has changed and requires a new RTP SSRC */
 AST_CONTROL_READ_ACTION = 27, /*!< Tell ast_read to take a specific action */
 AST_CONTROL_AOC = 28, /*!< Advice of Charge with encoded generic AOC payload */
 AST_CONTROL_END_OF_Q = 29, /*!< Indicate that this position was the end of the channel queue for a softhangup. */
 AST_CONTROL_INCOMPLETE = 30, /*!< Indication that the extension dialed is incomplete */
 AST_CONTROL_MCID = 31, /*!< Indicate that the caller is being malicious. */
 AST_CONTROL_UPDATE_RTP_PEER = 32, /*!< Interrupt the bridge and have it update the peer */
 AST_CONTROL_PVT_CAUSE_CODE = 33, /*!< Contains an update to the protocol-specific cause-code stored for branching dials */
 AST_CONTROL_MASQUERADE_NOTIFY = 34, /*!< A masquerade is about to begin/end. (Never sent as a frame but directly with ast_indicate_data().) */
 AST_CONTROL_STREAM_TOPOLOGY_REQUEST_CHANGE = 35, /*!< Channel indication that a stream topology change has been requested */
 AST_CONTROL_STREAM_TOPOLOGY_CHANGED = 36, /*!< Channel indication that a stream topology change has occurred */
 AST_CONTROL_STREAM_TOPOLOGY_SOURCE_CHANGED = 37, /*!< Channel indication that one of the source streams has changed its source */

 /*
 * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
 *
 * IAX2 sends these values out over the wire. To prevent future
 * incompatibilities, pick the next value in the enum from whatever
 * is on the current trunk. If you lose the merge race you need to
 * fix the previous branches to match what is on trunk. In addition
 * you need to change chan_iax2 to explicitly allow the control
 * frame over the wire if it makes sense for the frame to be passed
 * to another Asterisk instance.
 *
 * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
 */

 /* Control frames used to manipulate a stream on a channel. The values for these
 * must be greater than the allowed value for a 8-bit char, so that they avoid
 * conflicts with DTMF values. */
 AST_CONTROL_STREAM_STOP = 1000, /*!< Indicate to a channel in playback to stop the stream */
 AST_CONTROL_STREAM_SUSPEND = 1001, /*!< Indicate to a channel in playback to suspend the stream */
 AST_CONTROL_STREAM_RESTART = 1002, /*!< Indicate to a channel in playback to restart the stream */
 AST_CONTROL_STREAM_REVERSE = 1003, /*!< Indicate to a channel in playback to rewind */
 AST_CONTROL_STREAM_FORWARD = 1004, /*!< Indicate to a channel in playback to fast forward */
 /* Control frames to manipulate recording on a channel. */
 AST_CONTROL_RECORD_CANCEL = 1100, /*!< Indicated to a channel in record to stop recording and discard the file */
 AST_CONTROL_RECORD_STOP = 1101, /*!< Indicated to a channel in record to stop recording */
 AST_CONTROL_RECORD_SUSPEND = 1102, /*!< Indicated to a channel in record to suspend/unsuspend recording */
 AST_CONTROL_RECORD_MUTE = 1103, /*!< Indicated to a channel in record to mute/unmute (i.e. write silence) recording */
};

/*!
 * \brief Actions to indicate to, and be handled on channel read
 *
 * The subtype to specify for an AST_CONTROL_READ_ACTION frame. These
 * frames are then to be enacted on within a channel's read thread.
 */
enum ast_frame_read_action {
 AST_FRAME_READ_ACTION_CONNECTED_LINE_MACRO,
 AST_FRAME_READ_ACTION_SEND_TEXT,
 AST_FRAME_READ_ACTION_SEND_TEXT_DATA,
};

struct ast_control_read_action_payload {
 /* An indicator to ast_read of what action to
 * take with the frame;
 */
 enum ast_frame_read_action action;
 /* The size of the frame's payload
 */
 size_t payload_size;
 /* A payload for the frame.
 */
 unsigned char payload[0];
};

enum ast_control_t38 {
 AST_T38_REQUEST_NEGOTIATE = 1, /*!< Request T38 on a channel (voice to fax) */
 AST_T38_REQUEST_TERMINATE, /*!< Terminate T38 on a channel (fax to voice) */
 AST_T38_NEGOTIATED, /*!< T38 negotiated (fax mode) */
 AST_T38_TERMINATED, /*!< T38 terminated (back to voice) */
 AST_T38_REFUSED, /*!< T38 refused for some reason (usually rejected by remote end) */
 AST_T38_REQUEST_PARMS, /*!< request far end T.38 parameters for a channel in 'negotiating' state */
};

enum ast_control_t38_rate {
 AST_T38_RATE_2400 = 1,
 AST_T38_RATE_4800,
 AST_T38_RATE_7200,
 AST_T38_RATE_9600,
 AST_T38_RATE_12000,
 /* Set to 0 so it's taken as default when unspecified.
 * See ITU-T T.38 Implementors' Guide (11 May 2012),
 * Table H.2: if the T38MaxBitRate attribute is omitted
 * it should use a default of 14400. */
 AST_T38_RATE_14400 = 0,
};

enum ast_control_t38_rate_management {
 AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF = 0,
 AST_T38_RATE_MANAGEMENT_LOCAL_TCF,
};

struct ast_control_t38_parameters {
 enum ast_control_t38 request_response; /*!< Request or response of the T38 control frame */
 unsigned int version; /*!< Supported T.38 version */
 unsigned int max_ifp; /*!< Maximum IFP size supported */
 enum ast_control_t38_rate rate; /*!< Maximum fax rate supported */
 enum ast_control_t38_rate_management rate_management; /*!< Rate management setting */
 unsigned int fill_bit_removal:1; /*!< Set if fill bit removal can be used */
 unsigned int transcoding_mmr:1; /*!< Set if MMR transcoding can be used */
 unsigned int transcoding_jbig:1; /*!< Set if JBIG transcoding can be used */
};

enum ast_control_transfer {
 AST_TRANSFER_SUCCESS = 0, /*!< Transfer request on the channel worked */
 AST_TRANSFER_FAILED, /*!< Transfer request on the channel failed */
};

struct ast_control_pvt_cause_code {
 char chan_name[AST_CHANNEL_NAME]; /*!< Name of the channel that originated the cause information */
 unsigned int emulate_sip_cause:1; /*!< Indicates whether this should be used to emulate SIP_CAUSE support */
 int ast_cause; /*!< Asterisk cause code associated with this message */
 char code[1]; /*!< Tech-specific cause code information, beginning with the name of the tech */
};

/* Option identifiers and flags */
#define AST_OPTION_FLAG_REQUEST 0
#define AST_OPTION_FLAG_ACCEPT 1
#define AST_OPTION_FLAG_REJECT 2
#define AST_OPTION_FLAG_QUERY 4
#define AST_OPTION_FLAG_ANSWER 5
#define AST_OPTION_FLAG_WTF 6

/*! Verify touchtones by muting audio transmission
 * (and reception) and verify the tone is still present
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_TONE_VERIFY 1

/*! Put a compatible channel into TDD (TTY for the hearing-impared) mode
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_TDD 2

/*! Relax the parameters for DTMF reception (mainly for radio use)
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_RELAXDTMF 3

/*! Set (or clear) Audio (Not-Clear) Mode
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_AUDIO_MODE 4

/*! Set channel transmit gain
 * Option data is a single signed char representing number of decibels (dB)
 * to set gain to (on top of any gain specified in channel driver) */
#define AST_OPTION_TXGAIN 5

/*! Set channel receive gain
 * Option data is a single signed char representing number of decibels (dB)
 * to set gain to (on top of any gain specified in channel driver) */
#define AST_OPTION_RXGAIN 6

/* set channel into "Operator Services" mode
 * Option data is a struct oprmode
 *
 * \note This option should never be sent over the network */
#define AST_OPTION_OPRMODE 7

/*! Explicitly enable or disable echo cancelation for the given channel
 * Option data is a single signed char value 0 or 1
 *
 * \note This option appears to be unused in the code. It is handled, but never
 * set or queried. */
#define AST_OPTION_ECHOCAN 8

/*! \brief Handle channel write data
 * If a channel needs to process the data from a func_channel write operation
 * after func_channel_write executes, it can define the setoption callback
 * and process this option. A pointer to an ast_chan_write_info_t will be passed.
 *
 * \note This option should never be passed over the network. */
#define AST_OPTION_CHANNEL_WRITE 9

/* !
 * Read-only. Allows query current status of T38 on the channel.
 * data: ast_t38state
 */
#define AST_OPTION_T38_STATE 10

/*! Request that the channel driver deliver frames in a specific format
 * Option data is a format_t */
#define AST_OPTION_FORMAT_READ 11

/*! Request that the channel driver be prepared to accept frames in a specific format
 * Option data is a format_t */
#define AST_OPTION_FORMAT_WRITE 12

/*! Request that the channel driver make two channels of the same tech type compatible if possible
 * Option data is an ast_channel
 *
 * \note This option should never be passed over the network */
#define AST_OPTION_MAKE_COMPATIBLE 13

/*! Get or set the digit detection state of the channel
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_DIGIT_DETECT 14

/*! Get or set the fax tone detection state of the channel
 * Option data is a single signed char value 0 or 1 */
#define AST_OPTION_FAX_DETECT 15

/*! Get the device name from the channel (Read only)
 * Option data is a character buffer of suitable length */
#define AST_OPTION_DEVICE_NAME 16

/*! Get the CC agent type from the channel (Read only)
 * Option data is a character buffer of suitable length */
#define AST_OPTION_CC_AGENT_TYPE 17

/*! Get or set the security options on a channel
 * Option data is an integer value of 0 or 1 */
#define AST_OPTION_SECURE_SIGNALING 18
#define AST_OPTION_SECURE_MEDIA 19

struct oprmode {
 struct ast_channel *peer;
 int mode;
} ;

struct ast_option_header {
 /* Always keep in network byte order */
#if __BYTE_ORDER == __BIG_ENDIAN
 uint16_t flag:3;
 uint16_t option:13;
#else
#if __BYTE_ORDER == __LITTLE_ENDIAN
 uint16_t option:13;
 uint16_t flag:3;
#else
#error Byte order not defined
#endif
#endif
 uint8_t data[0];
};

/*! \brief Requests a frame to be allocated
 *
 * \param source
 * Request a frame be allocated. source is an optional source of the frame,
 * len is the requested length, or "0" if the caller will supply the buffer
 */
#if 0 /* Unimplemented */
struct ast_frame *ast_fralloc(char *source, int len);
#endif

/*!
 * \brief Frees a frame or list of frames
 *
 * \param fr Frame to free, or head of list to free
 * \param cache Whether to consider this frame for frame caching
 */
void ast_frame_free(struct ast_frame *fr, int cache);

#define ast_frfree(fr) ast_frame_free(fr, 1)

/*!
 * \brief NULL-safe wrapper for \ref ast_frfree, good for \ref RAII_VAR.
 * \param frame Frame to free, or head of list to free.
 */
void ast_frame_dtor(struct ast_frame *frame);

/*! \brief Makes a frame independent of any static storage
 * \param fr frame to act upon
 * Take a frame, and if it's not been malloc'd, make a malloc'd copy
 * and if the data hasn't been malloced then make the
 * data malloc'd. If you need to store frames, say for queueing, then
 * you should call this function.
 * \return Returns a frame on success, NULL on error
 * \note This function may modify the frame passed to it, so you must
 * not assume the frame will be intact after the isolated frame has
 * been produced. In other words, calling this function on a frame
 * should be the last operation you do with that frame before freeing
 * it (or exiting the block, if the frame is on the stack.)
 */
#define ast_frisolate(fr) __ast_frisolate(fr, __FILE__, __LINE__, __PRETTY_FUNCTION__)
struct ast_frame *__ast_frisolate(struct ast_frame *fr, const char *file, int line, const char *func);

/*! \brief Copies a frame
 * \param fr frame to copy
 * Duplicates a frame -- should only rarely be used, typically frisolate is good enough
 * \return Returns a frame on success, NULL on error
 */
#define ast_frdup(fr) __ast_frdup(fr, __FILE__, __LINE__, __PRETTY_FUNCTION__)
struct ast_frame *__ast_frdup(const struct ast_frame *fr, const char *file, int line, const char *func);

void ast_swapcopy_samples(void *dst, const void *src, int samples);

/* Helpers for byteswapping native samples to/from
 little-endian and big-endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define ast_frame_byteswap_le(fr) do { ; } while(0)
#define ast_frame_byteswap_be(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data.ptr, __f->data.ptr, __f->samples); } while(0)
#else
#define ast_frame_byteswap_le(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data.ptr, __f->data.ptr, __f->samples); } while(0)
#define ast_frame_byteswap_be(fr) do { ; } while(0)
#endif

void ast_frame_dump(const char *name, struct ast_frame *f, char *prefix);

/*! \brief Appends a frame to the end of a list of frames, truncating the maximum length of the list */
struct ast_frame *ast_frame_enqueue(struct ast_frame *head, struct ast_frame *f, int maxlen, int dupe);

/*!
 \brief Adjusts the volume of the audio samples contained in a frame.
 \param f The frame containing the samples (must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR)
 \param adjustment The number of dB to adjust up or down.
 \return 0 for success, non-zero for an error
 */
int ast_frame_adjust_volume(struct ast_frame *f, int adjustment);

/*!
 \brief Adjusts the volume of the audio samples contained in a frame.
 \param f The frame containing the samples (must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR)
 \param adjustment The number of dB to adjust up or down.
 \return 0 for success, non-zero for an error
 */
int ast_frame_adjust_volume_float(struct ast_frame *f, float adjustment);

/*!
 \brief Sums two frames of audio samples.
 \param f1 The first frame (which will contain the result)
 \param f2 The second frame
 \return 0 for success, non-zero for an error

 The frames must be AST_FRAME_VOICE and must contain AST_FORMAT_SLINEAR samples,
 and must contain the same number of samples.
 */
int ast_frame_slinear_sum(struct ast_frame *f1, struct ast_frame *f2);

/*!
 * \brief Clear all audio samples from an ast_frame. The frame must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR
 */
int ast_frame_clear(struct ast_frame *frame);

/*!
 * \brief Copy the discription of a frame's subclass into the provided string
 *
 * \param f The frame to get the information from
 * \param subclass Buffer to fill with subclass information
 * \param slen Length of subclass buffer
 * \param moreinfo Buffer to fill with additional information
 * \param mlen Length of moreinfo buffer
 * \return Pointer to subclass
 * \since 11
 */
char *ast_frame_subclass2str(struct ast_frame *f, char *subclass, size_t slen, char *moreinfo, size_t mlen);

/*!
 * \brief Copy the discription of a frame type into the provided string
 *
 * \param frame_type The frame type to be described
 * \param ftype Buffer to fill with frame type description
 * \param len Length of subclass buffer
 * \return Pointer to ftype
 * \since 11
 */
char *ast_frame_type2str(enum ast_frame_type frame_type, char *ftype, size_t len);

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif /* _ASTERISK_FRAME_H */