/* GStreamer
 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
 *
 * gstbufferstore.c: keep an easily accessible list of all buffers
 *
 * 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.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif
#include "gstbufferstore.h"
#include <gst/gstutils.h>
#include <string.h>

GST_DEBUG_CATEGORY_STATIC (gst_buffer_store_debug);
#define GST_CAT_DEFAULT gst_buffer_store_debug

enum
{
  CLEARED,
  BUFFER_ADDED,
  LAST_SIGNAL
};
enum
{
  ARG_0
};


static void gst_buffer_store_dispose (GObject * object);

static gboolean gst_buffer_store_add_buffer_func (GstBufferStore * store,
    GstBuffer * buffer);
static void gst_buffer_store_cleared_func (GstBufferStore * store);

static guint gst_buffer_store_signals[LAST_SIGNAL] = { 0 };

#define _do_init(bla) \
    GST_DEBUG_CATEGORY_INIT (gst_buffer_store_debug, "GstBufferStore", 0, "buffer store helper");

GST_BOILERPLATE_FULL (GstBufferStore, gst_buffer_store, GObject, G_TYPE_OBJECT,
    _do_init);


G_GNUC_UNUSED static void
debug_buffers (GstBufferStore * store)
{
  GList *walk = store->buffers;

  g_printerr ("BUFFERS in store:\n");
  while (walk) {
    g_print ("%15" G_GUINT64_FORMAT " - %7u\n", GST_BUFFER_OFFSET (walk->data),
        GST_BUFFER_SIZE (walk->data));
    walk = g_list_next (walk);
  }
  g_printerr ("\n");
}

static gboolean
continue_accu (GSignalInvocationHint * ihint, GValue * return_accu,
    const GValue * handler_return, gpointer data)
{
  gboolean do_continue = g_value_get_boolean (handler_return);

  g_value_set_boolean (return_accu, do_continue);

  return do_continue;
}
static void
gst_buffer_store_base_init (gpointer g_class)
{
}
static void
gst_buffer_store_class_init (GstBufferStoreClass * store_class)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (store_class);

  gobject_class->dispose = gst_buffer_store_dispose;

  gst_buffer_store_signals[CLEARED] = g_signal_new ("cleared",
      G_TYPE_FROM_CLASS (store_class), G_SIGNAL_RUN_LAST,
      G_STRUCT_OFFSET (GstBufferStoreClass, cleared), NULL, NULL,
      gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
  gst_buffer_store_signals[BUFFER_ADDED] = g_signal_new ("buffer-added",
      G_TYPE_FROM_CLASS (store_class), G_SIGNAL_RUN_LAST,
      G_STRUCT_OFFSET (GstBufferStoreClass, buffer_added), continue_accu, NULL,
      gst_marshal_BOOLEAN__POINTER, G_TYPE_BOOLEAN, 1, GST_TYPE_BUFFER);

  store_class->cleared = gst_buffer_store_cleared_func;
  store_class->buffer_added = gst_buffer_store_add_buffer_func;
}
static void
gst_buffer_store_init (GstBufferStore * store)
{
  store->buffers = NULL;
}
static void
gst_buffer_store_dispose (GObject * object)
{
  GstBufferStore *store = GST_BUFFER_STORE (object);

  gst_buffer_store_clear (store);

  parent_class->dispose (object);
}

static gboolean
gst_buffer_store_add_buffer_func (GstBufferStore * store, GstBuffer * buffer)
{
  g_assert (buffer != NULL);

  if (!GST_BUFFER_OFFSET_IS_VALID (buffer) &&
      store->buffers && GST_BUFFER_OFFSET_IS_VALID (store->buffers->data)) {
    /* we assumed valid offsets, but suddenly they are not anymore */
    GST_DEBUG_OBJECT (store,
        "attempting to add buffer %p with invalid offset to store with valid offset, abort",
        buffer);
    return FALSE;
  } else if (!store->buffers
      || !GST_BUFFER_OFFSET_IS_VALID (store->buffers->data)) {
    /* the starting buffer had an invalid offset, in that case we assume continuous buffers */
    GST_LOG_OBJECT (store, "adding buffer %p with invalid offset and size %u",
        buffer, GST_BUFFER_SIZE (buffer));
    gst_data_ref (GST_DATA (buffer));
    store->buffers = g_list_append (store->buffers, buffer);
    return TRUE;
  } else {
    /* both list and buffer have valid offsets, we can really go wild */
    GList *walk, *current_list = NULL;
    GstBuffer *current;

    g_assert (GST_BUFFER_OFFSET_IS_VALID (buffer));
    GST_LOG_OBJECT (store,
        "attempting to add buffer %p with offset %" G_GUINT64_FORMAT
        " and size %u", buffer, GST_BUFFER_OFFSET (buffer),
        GST_BUFFER_SIZE (buffer));
    /* we keep a sorted list of non-overlapping buffers */
    walk = store->buffers;
    while (walk) {
      current = GST_BUFFER (walk->data);
      current_list = walk;
      walk = g_list_next (walk);
      if (GST_BUFFER_OFFSET (current) < GST_BUFFER_OFFSET (buffer)) {
        continue;
      } else if (GST_BUFFER_OFFSET (current) == GST_BUFFER_OFFSET (buffer)) {
        guint needed_size;

        if (walk) {
          needed_size = MIN (GST_BUFFER_SIZE (buffer),
              GST_BUFFER_OFFSET (walk->data) - GST_BUFFER_OFFSET (current));
        } else {
          needed_size = GST_BUFFER_SIZE (buffer);
        }
        if (needed_size <= GST_BUFFER_SIZE (current)) {
          buffer = NULL;
          break;
        } else {
          if (needed_size < GST_BUFFER_SIZE (buffer)) {
            /* need to create subbuffer to not have overlapping data */
            GstBuffer *sub = gst_buffer_create_sub (buffer, 0, needed_size);

            g_assert (sub);
            buffer = sub;
          } else {
            gst_data_ref (GST_DATA (buffer));
          }
          /* replace current buffer with new one */
          GST_INFO_OBJECT (store,
              "replacing buffer %p with buffer %p with offset %" G_GINT64_FORMAT
              " and size %u", current_list->data, buffer,
              GST_BUFFER_OFFSET (buffer), GST_BUFFER_SIZE (buffer));
          gst_data_unref (GST_DATA (current_list->data));
          current_list->data = buffer;
          buffer = NULL;
          break;
        }
      } else if (GST_BUFFER_OFFSET (current) > GST_BUFFER_OFFSET (buffer)) {
        GList *previous = g_list_previous (current_list);
        guint64 start_offset = previous ?
            GST_BUFFER_OFFSET (previous->data) +
            GST_BUFFER_SIZE (previous->data) : 0;

        if (start_offset == GST_BUFFER_OFFSET (current)) {
          buffer = NULL;
          break;
        } else {
          /* we have data to insert */
          if (start_offset > GST_BUFFER_OFFSET (buffer) ||
              GST_BUFFER_OFFSET (buffer) + GST_BUFFER_SIZE (buffer) >
              GST_BUFFER_OFFSET (current)) {
            GstBuffer *sub;

            /* need a subbuffer */
            start_offset = GST_BUFFER_OFFSET (buffer) > start_offset ? 0 :
                start_offset - GST_BUFFER_OFFSET (buffer);
            sub = gst_buffer_create_sub (buffer, start_offset,
                MIN (GST_BUFFER_SIZE (buffer),
                    GST_BUFFER_OFFSET (current) - start_offset -
                    GST_BUFFER_OFFSET (buffer)));
            g_assert (sub);
            GST_BUFFER_OFFSET (sub) = start_offset + GST_BUFFER_OFFSET (buffer);
            buffer = sub;
          } else {
            gst_data_ref (GST_DATA (buffer));
          }
          GST_INFO_OBJECT (store,
              "adding buffer %p with offset %" G_GINT64_FORMAT " and size %u",
              buffer, GST_BUFFER_OFFSET (buffer), GST_BUFFER_SIZE (buffer));
          store->buffers =
              g_list_insert_before (store->buffers, current_list, buffer);
          buffer = NULL;
          break;
        }
      }
    }
    if (buffer) {
      gst_data_ref (GST_DATA (buffer));
      GST_INFO_OBJECT (store,
          "adding buffer %p with offset %" G_GINT64_FORMAT " and size %u",
          buffer, GST_BUFFER_OFFSET (buffer), GST_BUFFER_SIZE (buffer));
      if (current_list) {
        g_list_append (current_list, buffer);
      } else {
        g_assert (store->buffers == NULL);
        store->buffers = g_list_prepend (NULL, buffer);
      }
    }
    return TRUE;
  }
}
static void
gst_buffer_store_cleared_func (GstBufferStore * store)
{
  g_list_foreach (store->buffers, (GFunc) gst_data_unref, NULL);
  g_list_free (store->buffers);
  store->buffers = NULL;
}

/**
 * gst_buffer_store_new:
 *
 * Creates a new bufferstore.
 *
 * Returns: the new bufferstore.
 */
GstBufferStore *
gst_buffer_store_new (void)
{
  return GST_BUFFER_STORE (g_object_new (GST_TYPE_BUFFER_STORE, NULL));
}

/**
 * gst_buffer_store_clear:
 * @store: a bufferstore
 *
 * Clears the buffer store. All buffers are removed and the buffer store
 * behaves like it was just created.
 */
/* FIXME: call this function _reset ? */
void
gst_buffer_store_clear (GstBufferStore * store)
{
  g_return_if_fail (GST_IS_BUFFER_STORE (store));

  g_signal_emit (store, gst_buffer_store_signals[CLEARED], 0, NULL);
}

/**
 * gst_buffer_store_add_buffer:
 * @store: a bufferstore
 * @buffer: the buffer to add
 *
 * Adds a buffer to the buffer store. 
 *
 * Returns: TRUE, if the buffer was added, FALSE if an error occured.
 */
gboolean
gst_buffer_store_add_buffer (GstBufferStore * store, GstBuffer * buffer)
{
  gboolean ret;

  g_return_val_if_fail (GST_IS_BUFFER_STORE (store), FALSE);
  g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);

  if (store->buffers &&
      GST_BUFFER_OFFSET_IS_VALID (store->buffers->data) &&
      !GST_BUFFER_OFFSET_IS_VALID (buffer))
    return FALSE;

  g_signal_emit (store, gst_buffer_store_signals[BUFFER_ADDED], 0, buffer,
      &ret);

  return ret;
}

/**
 * gst_buffer_store_get_buffer:
 * @store: a bufferstore
 * @offset: starting offset of returned buffer
 * @size: size of returned buffer
 *
 * Returns a buffer that corresponds to the given area of data. If part of the
 * data is not available inside the store, NULL is returned. You have to unref
 * the buffer after use.
 *
 * Returns: a buffer with the requested data or NULL if the data was not 
 *          available.
 */
GstBuffer *
gst_buffer_store_get_buffer (GstBufferStore * store, guint64 offset, guint size)
{
  GstBuffer *current;
  GList *walk;
  guint8 *data;
  guint tmp;
  gboolean have_offset;
  guint64 cur_offset = 0;
  GstBuffer *ret = NULL;

  g_return_val_if_fail (GST_IS_BUFFER_STORE (store), NULL);

  walk = store->buffers;
  if (!walk)
    return NULL;
  if (GST_BUFFER_OFFSET_IS_VALID (walk->data)) {
    have_offset = TRUE;
  } else {
    have_offset = FALSE;
  }
  while (walk) {
    current = GST_BUFFER (walk->data);
    if (have_offset) {
      cur_offset = GST_BUFFER_OFFSET (current);
    }
    walk = g_list_next (walk);
    if (cur_offset > offset) {
      /* #include <windows.h>
         do_nothing_loop (); */
    } else if (cur_offset == offset && GST_BUFFER_SIZE (current) == size) {
      GST_LOG_OBJECT (store,
          "found matching buffer %p for offset %" G_GUINT64_FORMAT
          " and size %u", current, offset, size);
      ret = current;
      gst_data_ref (GST_DATA (ret));
      GST_LOG_OBJECT (store, "refcount %d", GST_DATA_REFCOUNT_VALUE (ret));
      break;
    } else if (cur_offset + GST_BUFFER_SIZE (current) > offset) {
      if (cur_offset + GST_BUFFER_SIZE (current) >= offset + size) {
        ret = gst_buffer_create_sub (current, offset - cur_offset, size);
        GST_LOG_OBJECT (store,
            "created subbuffer %p from buffer %p for offset %llu and size %u",
            ret, current, offset, size);
        break;
      }
      /* uh, the requested data spans some buffers */
      ret = gst_buffer_new_and_alloc (size);
      GST_BUFFER_OFFSET (ret) = offset;
      GST_LOG_OBJECT (store, "created buffer %p for offset %" G_GUINT64_FORMAT
          " and size %u, will fill with data now", ret, offset, size);
      data = GST_BUFFER_DATA (ret);
      tmp = GST_BUFFER_SIZE (current) - offset + cur_offset;
      memcpy (data, GST_BUFFER_DATA (current) + offset - cur_offset, tmp);
      data += tmp;
      size -= tmp;
      while (size) {
        if (walk == NULL ||
            (have_offset &&
                GST_BUFFER_OFFSET (current) + GST_BUFFER_SIZE (current) !=
                GST_BUFFER_OFFSET (walk->data))) {
          GST_DEBUG_OBJECT (store,
              "not all data for offset %" G_GUINT64_FORMAT
              " and remaining size %u available, aborting", offset, size);
          gst_data_unref (GST_DATA (ret));
          ret = NULL;
          goto out;
        }
        current = GST_BUFFER (walk->data);
        walk = g_list_next (walk);
        tmp = MIN (GST_BUFFER_SIZE (current), size);
        memcpy (data, GST_BUFFER_DATA (current), tmp);
        data += tmp;
        size -= tmp;
      }
    }
    if (!have_offset) {
      cur_offset += GST_BUFFER_SIZE (current);
    }
  }
out:

  return ret;
}

/**
 * gst_buffer_store_get_size:
 * @store: a bufferstore
 * @offset: desired offset
 *
 * Calculates the number of bytes available starting from offset. This allows
 * to query a buffer with the returned size.
 *
 * Returns: the number of continuous bytes in the bufferstore starting at
 *          offset.
 */
guint
gst_buffer_store_get_size (GstBufferStore * store, guint64 offset)
{
  GList *walk;
  gboolean have_offset;
  gboolean counting = FALSE;
  guint64 cur_offset = 0;
  GstBuffer *current = NULL;
  guint ret = 0;

  g_return_val_if_fail (GST_IS_BUFFER_STORE (store), 0);

  walk = store->buffers;
  if (!walk)
    return 0;
  if (GST_BUFFER_OFFSET_IS_VALID (walk->data)) {
    have_offset = TRUE;
  } else {
    have_offset = FALSE;
  }
  while (walk) {
    if (have_offset && counting &&
        cur_offset + GST_BUFFER_SIZE (current) !=
        GST_BUFFER_OFFSET (walk->data)) {
      break;
    }
    current = GST_BUFFER (walk->data);
    if (have_offset) {
      cur_offset = GST_BUFFER_OFFSET (current);
    }
    walk = g_list_next (walk);
    if (counting) {
      ret += GST_BUFFER_SIZE (current);
    } else {
      if (cur_offset > offset)
        return 0;
      if (cur_offset + GST_BUFFER_SIZE (current) > offset) {
        /* we have at least some bytes */
        ret = cur_offset + GST_BUFFER_SIZE (current) - offset;
        counting = TRUE;
      }
    }
    if (!have_offset) {
      cur_offset += GST_BUFFER_SIZE (current);
    }
  }

  return ret;
}