/* GStreamer

 * Copyright (C) 2005 Wim Taymans <wim@fluendo.com>

 *

 * gstsegment.c: GstSegment subsystem

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#include "gst_private.h"

#include "gstutils.h"

#include "gstsegment.h"

/**

 * SECTION:gstsegment

 * @short_description: Structure describing the configured region of interest

 *                     in a media file.

 * @see_also: #GstEvent

 *

 * This helper structure holds the relevant values for tracking the region of

 * interest in a media file, called a segment. 

 *

 * The structure can be used for two purposes:

 * <itemizedlist>

 *   <listitem><para>performing seeks (handling seek events)</para></listitem>

 *   <listitem><para>tracking playback regions (handling newsegment events)</para></listitem>

 * </itemizedlist>

 *

 * The segment is usually configured by the application with a seek event which 

 * is propagated upstream and eventually handled by an element that performs the seek.

 *

 * The configured segment is then propagated back downstream with a newsegment event.

 * This information is then used to clip media to the segment boundaries.

 *

 * A segment structure is initialized with gst_segment_init(), which takes a #GstFormat

 * that will be used as the format of the segment values. The segment will be configured

 * with a start value of 0 and a stop/duration of -1, which is undefined. The default

 * rate and applied_rate is 1.0.

 *

 * If the segment is used for managing seeks, the segment duration should be set with

 * gst_segment_set_duration(). The public duration field contains the duration of the

 * segment. When using the segment for seeking, the start and time members should 

 * normally be left to their default 0 value. The stop position is left to -1 unless

 * explicitly configured to a different value after a seek event.

 *

 * The current position in the segment should be set with the gst_segment_set_last_stop().

 * The public last_stop field contains the last set stop position in the segment.

 *

 * For elements that perform seeks, the current segment should be updated with the

 * gst_segment_set_seek() and the values from the seek event. This method will update

 * all the segment fields. The last_stop field will contain the new playback position.

 * If the cur_type was different from GST_SEEK_TYPE_NONE, playback continues from

 * the last_stop position, possibly with updated flags or rate.

 *

 * For elements that want to use #GstSegment to track the playback region, use

 * gst_segment_set_newsegment() to update the segment fields with the information from

 * the newsegment event. The gst_segment_clip() method can be used to check and clip

 * the media data to the segment boundaries.

 *

 * For elements that want to synchronize to the pipeline clock, gst_segment_to_running_time()

 * can be used to convert a timestamp to a value that can be used to synchronize

 * to the clock. This function takes into account all accumulated segments as well as

 * any rate or applied_rate conversions.

 *

 * For elements that need to perform operations on media data in stream_time, 

 * gst_segment_to_stream_time() can be used to convert a timestamp and the segment

 * info to stream time (which is always between 0 and the duration of the stream).

 *

 * Last reviewed on 2007-05-17 (0.10.13)

 */

static GstSegment *

gst_segment_copy (GstSegment * segment)

{

  GstSegment *result = NULL;

  if (segment) {

    result = gst_segment_new ();

    memcpy (result, segment, sizeof (GstSegment));

  }

  return result;

}

#ifdef __SYMBIAN32__

EXPORT_C

#endif

GType

gst_segment_get_type (void)

{

  static GType gst_segment_type = 0;

  if (G_UNLIKELY (gst_segment_type == 0)) {

    gst_segment_type = g_boxed_type_register_static ("GstSegment",

        (GBoxedCopyFunc) gst_segment_copy, (GBoxedFreeFunc) gst_segment_free);

  }

  return gst_segment_type;

}

/**

 * gst_segment_new:

 *

 * Allocate a new #GstSegment structure and initialize it using 

 * gst_segment_init().

 *

 * Returns: a new #GstSegment, free with gst_segment_free().

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

GstSegment *

gst_segment_new (void)

{

  GstSegment *result;

  result = g_new0 (GstSegment, 1);

  gst_segment_init (result, GST_FORMAT_UNDEFINED);

  return result;

}

/**

 * gst_segment_free:

 * @segment: a #GstSegment

 *

 * Free the allocated segment @segment.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_free (GstSegment * segment)

{

  g_free (segment);

}

/**

 * gst_segment_init:

 * @segment: a #GstSegment structure.

 * @format: the format of the segment.

 *

 * The start/last_stop positions are set to 0 and the stop/duration

 * fields are set to -1 (unknown). The default rate of 1.0 and no

 * flags are set.

 *

 * Initialize @segment to its default values.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_init (GstSegment * segment, GstFormat format)

{

  g_return_if_fail (segment != NULL);

  segment->rate = 1.0;

  segment->abs_rate = 1.0;

  segment->applied_rate = 1.0;

  segment->format = format;

  segment->flags = 0;

  segment->start = 0;

  segment->stop = -1;

  segment->time = 0;

  segment->accum = 0;

  segment->last_stop = 0;

  segment->duration = -1;

}

/**

 * gst_segment_set_duration:

 * @segment: a #GstSegment structure.

 * @format: the format of the segment.

 * @duration: the duration of the segment info or -1 if unknown.

 *

 * Set the duration of the segment to @duration. This function is mainly

 * used by elements that perform seeking and know the total duration of the

 * segment. 

 * 

 * This field should be set to allow seeking requests relative to the

 * duration.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_set_duration (GstSegment * segment, GstFormat format,

    gint64 duration)

{

  g_return_if_fail (segment != NULL);

  if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))

    segment->format = format;

  else

    g_return_if_fail (segment->format == format);

  segment->duration = duration;

}

/**

 * gst_segment_set_last_stop:

 * @segment: a #GstSegment structure.

 * @format: the format of the segment.

 * @position: the position 

 *

 * Set the last observed stop position in the segment to @position.

 *

 * This field should be set to allow seeking requests relative to the

 * current playing position.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_set_last_stop (GstSegment * segment, GstFormat format,

    gint64 position)

{

  g_return_if_fail (segment != NULL);

  if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))

    segment->format = format;

  else

    g_return_if_fail (segment->format == format);

  segment->last_stop = MAX (segment->start, position);

}

/**

 * gst_segment_set_seek:

 * @segment: a #GstSegment structure.

 * @rate: the rate of the segment.

 * @format: the format of the segment.

 * @flags: the seek flags for the segment

 * @start_type: the seek method

 * @start: the seek start value

 * @stop_type: the seek method

 * @stop: the seek stop value

 * @update: boolean holding whether last_stop was updated.

 *

 * Update the segment structure with the field values of a seek event (see

 * gst_event_new_seek()).

 *

 * After calling this method, the segment field last_stop and time will

 * contain the requested new position in the segment. The new requested

 * position in the segment depends on @rate and @start_type and @stop_type. 

 *

 * For positive @rate, the new position in the segment is the new @segment

 * start field when it was updated with a @start_type different from

 * #GST_SEEK_TYPE_NONE. If no update was performed on @segment start position

 * (#GST_SEEK_TYPE_NONE), @start is ignored and @segment last_stop is

 * unmodified.

 *

 * For negative @rate, the new position in the segment is the new @segment

 * stop field when it was updated with a @stop_type different from

 * #GST_SEEK_TYPE_NONE. If no stop was previously configured in the segment, the

 * duration of the segment will be used to update the stop position.

 * If no update was performed on @segment stop position (#GST_SEEK_TYPE_NONE),

 * @stop is ignored and @segment last_stop is unmodified.

 *

 * The applied rate of the segment will be set to 1.0 by default.

 * If the caller can apply a rate change, it should update @segment

 * rate and applied_rate after calling this function.

 *

 * @update will be set to TRUE if a seek should be performed to the segment 

 * last_stop field. This field can be FALSE if, for example, only the @rate

 * has been changed but not the playback position.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_set_seek (GstSegment * segment, gdouble rate,

    GstFormat format, GstSeekFlags flags,

    GstSeekType start_type, gint64 start,

    GstSeekType stop_type, gint64 stop, gboolean * update)

{

  gboolean update_stop, update_start;

  gint64 last_stop;

  g_return_if_fail (rate != 0.0);

  g_return_if_fail (segment != NULL);

  if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))

    segment->format = format;

  update_start = update_stop = TRUE;

  /* segment->start is never invalid */

  switch (start_type) {

    case GST_SEEK_TYPE_NONE:

      /* no update to segment, take previous start */

      start = segment->start;

      update_start = FALSE;

      break;

    case GST_SEEK_TYPE_SET:

      /* start holds desired position, map -1 to the start */

      if (start == -1)

        start = 0;

      /* start must be 0 or the formats must match */

      g_return_if_fail (start == 0 || segment->format == format);

      break;

    case GST_SEEK_TYPE_CUR:

      g_return_if_fail (start == 0 || segment->format == format);

      /* add start to currently configured segment */

      start = segment->start + start;

      break;

    case GST_SEEK_TYPE_END:

      if (segment->duration != -1) {

        g_return_if_fail (start == 0 || segment->format == format);

        /* add start to total length */

        start = segment->duration + start;

      } else {

        /* no update if duration unknown */

        start = segment->start;

        update_start = FALSE;

      }

      break;

  }

  /* bring in sane range */

  if (segment->duration != -1)

    start = CLAMP (start, 0, segment->duration);

  else

    start = MAX (start, 0);

  /* stop can be -1 if we have not configured a stop. */

  switch (stop_type) {

    case GST_SEEK_TYPE_NONE:

      stop = segment->stop;

      update_stop = FALSE;

      break;

    case GST_SEEK_TYPE_SET:

      /* stop holds required value, if it's not -1, it must be of the same

       * format as the segment. */

      g_return_if_fail (stop == -1 || segment->format == format);

      break;

    case GST_SEEK_TYPE_CUR:

      if (segment->stop != -1) {

        /* only add compatible formats or 0 */

        g_return_if_fail (stop == 0 || segment->format == format);

        stop = segment->stop + stop;

      } else

        stop = -1;

      break;

    case GST_SEEK_TYPE_END:

      if (segment->duration != -1) {

        /* only add compatible formats or 0 */

        g_return_if_fail (stop == 0 || segment->format == format);

        stop = segment->duration + stop;

      } else {

        stop = segment->stop;

        update_stop = FALSE;

      }

      break;

  }

  /* if we have a valid stop time, make sure it is clipped */

  if (stop != -1) {

    if (segment->duration != -1)

      stop = CLAMP (stop, 0, segment->duration);

    else

      stop = MAX (stop, 0);

  }

  /* we can't have stop before start */

  if (stop != -1)

    g_return_if_fail (start <= stop);

  segment->rate = rate;

  segment->abs_rate = ABS (rate);

  segment->applied_rate = 1.0;

  segment->flags = flags;

  segment->start = start;

  segment->stop = stop;

  segment->time = start;

  last_stop = segment->last_stop;

  if (update_start && rate > 0.0) {

    last_stop = start;

  }

  if (update_stop && rate < 0.0) {

    if (stop != -1)

      last_stop = stop;

    else {

      if (segment->duration != -1)

        last_stop = segment->duration;

      else

        last_stop = 0;

    }

  }

  /* set update arg to reflect update of last_stop */

  if (update)

    *update = last_stop != segment->last_stop;

  /* update new position */

  segment->last_stop = last_stop;

}

/**

 * gst_segment_set_newsegment:

 * @segment: a #GstSegment structure.

 * @update: flag indicating a new segment is started or updated

 * @rate: the rate of the segment.

 * @format: the format of the segment.

 * @start: the new start value

 * @stop: the new stop value

 * @time: the new stream time

 *

 * Update the segment structure with the field values of a new segment event and

 * with a default applied_rate of 1.0.

 *

 * Since: 0.10.6

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_set_newsegment (GstSegment * segment, gboolean update, gdouble rate,

    GstFormat format, gint64 start, gint64 stop, gint64 time)

{

  gst_segment_set_newsegment_full (segment, update, rate, 1.0, format, start,

      stop, time);

}

/**

 * gst_segment_set_newsegment_full:

 * @segment: a #GstSegment structure.

 * @update: flag indicating a new segment is started or updated

 * @rate: the rate of the segment.

 * @applied_rate: the applied rate of the segment.

 * @format: the format of the segment.

 * @start: the new start value

 * @stop: the new stop value

 * @time: the new stream time

 *

 * Update the segment structure with the field values of a new segment event.

 */

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

gst_segment_set_newsegment_full (GstSegment * segment, gboolean update,

    gdouble rate, gdouble applied_rate, GstFormat format, gint64 start,

    gint64 stop, gint64 time)

{

  gint64 duration;

  g_return_if_fail (rate != 0.0);

  g_return_if_fail (applied_rate != 0.0);

  g_return_if_fail (segment != NULL);

  if (G_UNLIKELY (segment->format == GST_FORMAT_UNDEFINED))

    segment->format = format;

  /* any other format with 0 also gives time 0, the other values are

   * invalid in the format though. */

  if (format != segment->format && start == 0) {

    format = segment->format;

    if (stop != 0)

      stop = -1;

    if (time != 0)

      time = -1;

  }

  g_return_if_fail (segment->format == format);

  if (update) {

    if (segment->rate > 0.0) {

      /* an update to the current segment is done, elapsed time is

       * difference between the old start and new start. */

      if (start > segment->start)

        duration = start - segment->start;

      else

        duration = 0;

    } else {

      /* for negative rates, the elapsed duration is the diff between the stop

       * positions */

      if (stop != -1 && stop < segment->stop)

        duration = segment->stop - stop;

      else

        duration = 0;

    }

  } else {

    /* the new segment has to be aligned with the old segment.

     * We first update the accumulated time of the previous

     * segment. the accumulated time is used when syncing to the

     * clock. 

     */

    if (segment->stop != -1) {

      duration = segment->stop - segment->start;

    } else if (segment->last_stop != -1) {

      /* else use last seen timestamp as segment stop */

      duration = segment->last_stop - segment->start;

    } else {

      /* else we don't know and throw a warning.. really, this should

       * be fixed in the element. */

      g_warning ("closing segment of unknown duration, assuming duration of 0");

      duration = 0;

    }

  }

  /* use previous rate to calculate duration */

  if (segment->abs_rate != 1.0)

    duration /= segment->abs_rate;

  /* accumulate duration */

  segment->accum += duration;