Line-Following-Robot/Input/Externals/raspicam-master/dependencies/mmal/mmal_buffer.h

/*
Copyright (c) 2012, Broadcom Europe Ltd
All rights reserved.

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modification, are permitted provided that the following conditions are met:
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      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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*/

#ifndef MMAL_BUFFER_H
#define MMAL_BUFFER_H

#ifdef __cplusplus
extern "C" {
#endif

/** \defgroup MmalBufferHeader Buffer headers
 * Definition of a buffer header and its associated API.
 * Buffer headers are the basic element used to pass data and information between different
 * parts of the system. They are passed to components via ports and sent back to the client
 * using a callback mechanism.
 */
/* @{ */

/** Specific data associated with video frames */
typedef struct {
   uint32_t planes;     /**< Number of planes composing the video frame */
   uint32_t offset[4];  /**< Offsets to the different planes. These must point within the
                             payload buffer */
   uint32_t pitch[4];   /**< Pitch (size in bytes of a line of a plane) of the different
                             planes */
   uint32_t flags;      /**< Flags describing video specific properties of a buffer header
                             (see \ref videobufferheaderflags "Video buffer header flags") */
   /* TBD stereoscopic support */
} MMAL_BUFFER_HEADER_VIDEO_SPECIFIC_T;

/** Type specific data that's associated with a payload buffer */
typedef union
{
   /** Specific data associated with video frames */
   MMAL_BUFFER_HEADER_VIDEO_SPECIFIC_T video;

} MMAL_BUFFER_HEADER_TYPE_SPECIFIC_T;

/** Definition of the buffer header structure.
 * A buffer header does not directly carry the data to be passed to a component but instead
 * it references the actual data using a pointer (and an associated length).
 * It also contains an internal area which can be used to store command or metadata to be
 * associated with the external data.
 */
typedef struct MMAL_BUFFER_HEADER_T
{
   struct MMAL_BUFFER_HEADER_T *next; /**< Used to link several buffer headers together */

   struct MMAL_BUFFER_HEADER_PRIVATE_T *priv; /**< Data private to the framework */

   uint32_t cmd;              /**< Defines what the buffer header contains. This is a FourCC
                                   with 0 as a special value meaning stream data */

   uint8_t  *data;            /**< Pointer to the start of the payload buffer (should not be
                                   changed by component) */
   uint32_t alloc_size;       /**< Allocated size in bytes of payload buffer */
   uint32_t length;           /**< Number of bytes currently used in the payload buffer (starting
                                   from offset) */
   uint32_t offset;           /**< Offset in bytes to the start of valid data in the payload buffer */

   uint32_t flags;            /**< Flags describing properties of a buffer header (see
                                   \ref bufferheaderflags "Buffer header flags") */

   int64_t  pts;              /**< Presentation timestamp in microseconds. \ref MMAL_TIME_UNKNOWN
                                   is used when the pts is unknown. */
   int64_t  dts;              /**< Decode timestamp in microseconds (dts = pts, except in the case
                                   of video streams with B frames). \ref MMAL_TIME_UNKNOWN
                                   is used when the dts is unknown. */

   /** Type specific data that's associated with a payload buffer */
   MMAL_BUFFER_HEADER_TYPE_SPECIFIC_T *type;

   void *user_data;           /**< Field reserved for use by the client */

} MMAL_BUFFER_HEADER_T;

/** \name Buffer header flags
 * \anchor bufferheaderflags
 * The following flags describe properties of a buffer header */
/* @{ */
/** Signals that the current payload is the end of the stream of data */
#define MMAL_BUFFER_HEADER_FLAG_EOS                    (1<<0)
/** Signals that the start of the current payload starts a frame */
#define MMAL_BUFFER_HEADER_FLAG_FRAME_START            (1<<1)
/** Signals that the end of the current payload ends a frame */
#define MMAL_BUFFER_HEADER_FLAG_FRAME_END              (1<<2)
/** Signals that the current payload contains only complete frames (1 or more) */
#define MMAL_BUFFER_HEADER_FLAG_FRAME                  (MMAL_BUFFER_HEADER_FLAG_FRAME_START|MMAL_BUFFER_HEADER_FLAG_FRAME_END)
/** Signals that the current payload is a keyframe (i.e. self decodable) */
#define MMAL_BUFFER_HEADER_FLAG_KEYFRAME               (1<<3)
/** Signals a discontinuity in the stream of data (e.g. after a seek).
 * Can be used for instance by a decoder to reset its state */
#define MMAL_BUFFER_HEADER_FLAG_DISCONTINUITY          (1<<4)
/** Signals a buffer containing some kind of config data for the component
 * (e.g. codec config data) */
#define MMAL_BUFFER_HEADER_FLAG_CONFIG                 (1<<5)
/** Signals an encrypted payload */
#define MMAL_BUFFER_HEADER_FLAG_ENCRYPTED              (1<<6)
/** Signals a buffer containing side information */
#define MMAL_BUFFER_HEADER_FLAG_CODECSIDEINFO          (1<<7)
/** Signals a buffer which is the snapshot/postview image from a stills capture */
#define MMAL_BUFFER_HEADER_FLAGS_SNAPSHOT              (1<<8)
/** Signals a buffer which contains data known to be corrupted */
#define MMAL_BUFFER_HEADER_FLAG_CORRUPTED              (1<<9)
/** Signals that a buffer failed to be transmitted */
#define MMAL_BUFFER_HEADER_FLAG_TRANSMISSION_FAILED    (1<<10)
/** Signals the output buffer won't be used, just update reference frames */
#define MMAL_BUFFER_HEADER_FLAG_DECODEONLY             (1<<11)
/** User flags - can be passed in and will get returned */
#define MMAL_BUFFER_HEADER_FLAG_USER0                  (1<<28)
#define MMAL_BUFFER_HEADER_FLAG_USER1                  (1<<29)
#define MMAL_BUFFER_HEADER_FLAG_USER2                  (1<<30)
#define MMAL_BUFFER_HEADER_FLAG_USER3                  (1<<31)
/* @} */

/** \name Video buffer header flags
 * \anchor videobufferheaderflags
 * The following flags describe properties of a video buffer header */
/* @{ */
/** Signals an interlaced video frame */
#define MMAL_BUFFER_HEADER_VIDEO_FLAG_INTERLACED       (1<<0)
/** Signals that the top field of the current interlaced frame should be displayed first */
#define MMAL_BUFFER_HEADER_VIDEO_FLAG_TOP_FIELD_FIRST  (1<<2)
/** Signals that the buffer should be displayed on external display if attached. */
#define MMAL_BUFFER_HEADER_VIDEO_FLAG_DISPLAY_EXTERNAL (1<<3)
/** Signals that contents of the buffer requires copy protection. */
#define MMAL_BUFFER_HEADER_VIDEO_FLAG_PROTECTED        (1<<4)
/* @} */

/** Acquire a buffer header.
 * Acquiring a buffer header increases a reference counter on it and makes sure that the
 * buffer header won't be recycled until all the references to it are gone.
 * This is useful for instance if a component needs to return a buffer header but still needs
 * access to it for some internal processing (e.g. reference frames in video codecs).
 *
 * @param header buffer header to acquire
 */
void mmal_buffer_header_acquire(MMAL_BUFFER_HEADER_T *header);

/** Reset a buffer header.
 * Resets all header variables to default values.
 *
 * @param header buffer header to reset
 */
void mmal_buffer_header_reset(MMAL_BUFFER_HEADER_T *header);

/** Release a buffer header.
 * Releasing a buffer header will decrease its reference counter and when no more references
 * are left, the buffer header will be recycled by calling its 'release' callback function.
 *
 * If a pre-release callback is set (\ref MMAL_BH_PRE_RELEASE_CB_T), this will be invoked
 * before calling the buffer's release callback and potentially postpone buffer recycling.
 * Once pre-release is complete the buffer header is recycled with
 * \ref mmal_buffer_header_release_continue.
 *
 * @param header buffer header to release
 */
void mmal_buffer_header_release(MMAL_BUFFER_HEADER_T *header);

/** Continue the buffer header release process.
 * This should be called to complete buffer header recycling once all pre-release activity
 * has been completed.
 *
 * @param header buffer header to release
 */
void mmal_buffer_header_release_continue(MMAL_BUFFER_HEADER_T *header);

/** Buffer header pre-release callback.
 * The callback is invoked just before a buffer is released back into a
 * pool. This is used by clients who need to trigger additional actions
 * before the buffer can finally be released (e.g. wait for a bulk transfer
 * to complete).
 *
 * The callback should return TRUE if the buffer release need to be post-poned.
 *
 * @param header   buffer header about to be released
 * @param userdata user-specific data
 *
 * @return TRUE if the buffer should not be released
 */
typedef MMAL_BOOL_T (*MMAL_BH_PRE_RELEASE_CB_T)(MMAL_BUFFER_HEADER_T *header, void *userdata);

/** Set a buffer header pre-release callback.
 * If the callback is NULL, the buffer will be released back into the pool
 * immediately as usual.
 *
 * @param header   buffer header to associate callback with
 * @param cb       pre-release callback to invoke
 * @param userdata user-specific data
 */
void mmal_buffer_header_pre_release_cb_set(MMAL_BUFFER_HEADER_T *header, MMAL_BH_PRE_RELEASE_CB_T cb, void *userdata);

/** Replicate a buffer header into another one.
 * Replicating a buffer header will not only do an exact copy of all the public fields of the
 * buffer header (including data and alloc_size), but it will also acquire a reference to the
 * source buffer header which will only be released once the replicate has been released.
 *
 * @param dest buffer header into which to replicate
 * @param src buffer header to use as the source for the replication
 * @return MMAL_SUCCESS on success
 */
MMAL_STATUS_T mmal_buffer_header_replicate(MMAL_BUFFER_HEADER_T *dest, MMAL_BUFFER_HEADER_T *src);

/** Lock the data buffer contained in the buffer header in memory.
 * This call does nothing on all platforms except VideoCore where it is needed to pin a
 * buffer in memory before any access to it.
 *
 * @param header buffer header to lock
 */
MMAL_STATUS_T mmal_buffer_header_mem_lock(MMAL_BUFFER_HEADER_T *header);

/** Unlock the data buffer contained in the buffer header.
 * This call does nothing on all platforms except VideoCore where it is needed to un-pin a
 * buffer in memory after any access to it.
 *
 * @param header buffer header to unlock
 */
void mmal_buffer_header_mem_unlock(MMAL_BUFFER_HEADER_T *header);

/* @} */

#ifdef __cplusplus
}
#endif

#endif /* MMAL_BUFFER_H */