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/** @file
* codecs interface 2007 Tomas Kukosa
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifndef _CODECS_H_
#define _CODECS_H_
#include "ws_symbol_export.h"
#include "ws_attributes.h"
#include <stdbool.h>
#include "wsutil/wmem/wmem_map.h"
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
typedef struct {
void (*register_codec_module)(void); /* routine to call to register a codec */
} codecs_plugin;
WS_DLL_PUBLIC void codecs_register_plugin(const codecs_plugin *plug);
/**
* For all built-in codecs and codec plugins, call their register routines.
*/
WS_DLL_PUBLIC void codecs_init(void);
WS_DLL_PUBLIC void codecs_cleanup(void);
/**
* Get compile-time information for libraries used by libwscodecs.
*/
WS_DLL_PUBLIC void codec_get_compiled_version_info(GString *str);
struct codec_handle;
typedef struct codec_handle *codec_handle_t;
typedef struct _codec_context_t {
unsigned sample_rate;
unsigned channels;
wmem_map_t *fmtp_map;
void *priv; /* Private state set by the decoder */
} codec_context_t;
/*****************************************************************************/
/* Interface which must be implemented by a codec */
/* Codec decodes bytes to samples. Sample is 2 bytes! Codec writer must
* be careful when API refers bytes and when samples and its counts.
*/
/*****************************************************************************/
/** Initialize context of codec.
* Context can contain any information required by codec to pass between calls
* Note: There is just one codec context in runtime therefore no RTP stream
* related information should be stored in the context!
*
* @return Pointer to codec context
*/
typedef void *(*codec_init_fn)(codec_context_t *context);
/** Destroy context of codec
*
* @param context Pointer to codec context
*/
typedef void (*codec_release_fn)(codec_context_t *context);
/** Get count of channels provided by the codec
*
* @param context Pointer to codec context
*
* @return Count of channels (e.g. 1)
*/
typedef unsigned (*codec_get_channels_fn)(codec_context_t *context);
/** Get frequency/rate provided by the codec
*
* @param context Pointer to codec context
*
* @return Frequency (e.g. 8000)
*/
typedef unsigned (*codec_get_frequency_fn)(codec_context_t *context);
/** Decode one frame of payload
* Function is called twice, with different values of parameters:
* (1) To query size of required buffer in bytes for decoded samples
* pointed by inputBytes:
* outputSamples or outputSamplesSize must be set NULL
* (2) To decode samples:
* outputSamples points to allocated memory, outputSamplesSize is set to
* value returned in step (1)
*
* @param context Pointer to codec context
* @param inputBytes Pointer to input frame
* @param inputBytesSize Length of input frame in bytes
* (count of bytes to decode)
* @param outputSamples Pointer to output buffer with samples
* @param outputSamplesSize Length of output buffer in bytes (not samples!)
* Function can override this value. All codecs set it to same value as it returns in (2) when (2) is called.
*
* @return Count of reqired bytes (!not samples) to allocate in (1) or
* Count of decoded bytes (!not samples) in (2)
*/
typedef size_t (*codec_decode_fn)(codec_context_t *context,
const void *inputBytes, size_t inputBytesSize,
void *outputSamples, size_t *outputSamplesSize);
/*****************************************************************************/
/* Codec registering interface */
/*****************************************************************************/
WS_DLL_PUBLIC bool register_codec(const char *name, codec_init_fn init_fn,
codec_release_fn release_fn, codec_get_channels_fn channels_fn,
codec_get_frequency_fn frequency_fn, codec_decode_fn decode_fn);
WS_DLL_PUBLIC bool deregister_codec(const char *name);
WS_DLL_PUBLIC codec_handle_t find_codec(const char *name);
WS_DLL_PUBLIC void *codec_init(codec_handle_t codec, codec_context_t *context);
WS_DLL_PUBLIC void codec_release(codec_handle_t codec, codec_context_t *context);
WS_DLL_PUBLIC unsigned codec_get_channels(codec_handle_t codec, codec_context_t *context);
WS_DLL_PUBLIC unsigned codec_get_frequency(codec_handle_t codec, codec_context_t *context);
WS_DLL_PUBLIC size_t codec_decode(codec_handle_t codec, codec_context_t *context,
const void *inputBytes, size_t inputBytesSize,
void *outputSamples, size_t *outputSamplesSize);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _CODECS_H_ */
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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