/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * gstasyncdisksrc.c: 
 *
 * 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 <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>

//#define GST_DEBUG_ENABLED

#include "gstasyncdisksrc.h"


GstElementDetails gst_asyncdisksrc_details = {
  "Asynchronous Disk Source",
  "Source/File",
  "Read from arbitrary point in a file",
  VERSION,
  "Erik Walthinsen <omega@cse.ogi.edu>",
  "(C) 1999",
};


/* AsyncDiskSrc signals and args */
enum {
  /* FILL ME */
  LAST_SIGNAL
};

enum {
  ARG_0,
  ARG_LOCATION,
  ARG_BYTESPERREAD,
  ARG_OFFSET,
  ARG_SIZE,
};


static void 			gst_asyncdisksrc_class_init	(GstAsyncDiskSrcClass *klass);
static void 			gst_asyncdisksrc_init		(GstAsyncDiskSrc *asyncdisksrc);

static void 			gst_asyncdisksrc_set_arg	(GtkObject *object, GtkArg *arg, guint id);
static void 			gst_asyncdisksrc_get_arg	(GtkObject *object, GtkArg *arg, guint id);

static GstBuffer *		gst_asyncdisksrc_get		(GstPad *pad);
static GstBuffer *		gst_asyncdisksrc_get_region	(GstPad *pad, gulong offset, gulong size);

static GstElementStateReturn 	gst_asyncdisksrc_change_state	(GstElement *element);


static GstElementClass *parent_class = NULL;
//static guint gst_asyncdisksrc_signals[LAST_SIGNAL] = { 0 };

GtkType
gst_asyncdisksrc_get_type(void) 
{
  static GtkType asyncdisksrc_type = 0;

  if (!asyncdisksrc_type) {
    static const GtkTypeInfo asyncdisksrc_info = {
      "GstAsyncDiskSrc",
      sizeof(GstAsyncDiskSrc),
      sizeof(GstAsyncDiskSrcClass),
      (GtkClassInitFunc)gst_asyncdisksrc_class_init,
      (GtkObjectInitFunc)gst_asyncdisksrc_init,
      (GtkArgSetFunc)gst_asyncdisksrc_set_arg,
      (GtkArgGetFunc)gst_asyncdisksrc_get_arg,
      (GtkClassInitFunc)NULL,
    };
    asyncdisksrc_type = gtk_type_unique (GST_TYPE_ELEMENT, &asyncdisksrc_info);
  }
  return asyncdisksrc_type;
}

static void
gst_asyncdisksrc_class_init (GstAsyncDiskSrcClass *klass) 
{
  GtkObjectClass *gtkobject_class;
  GstElementClass *gstelement_class;

  gtkobject_class = (GtkObjectClass*)klass;
  gstelement_class = (GstElementClass*)klass;

  parent_class = gtk_type_class (GST_TYPE_ELEMENT);

  gtk_object_add_arg_type ("GstAsyncDiskSrc::location", GST_TYPE_FILENAME,
                           GTK_ARG_READWRITE, ARG_LOCATION);
  gtk_object_add_arg_type ("GstAsyncDiskSrc::bytesperread", GTK_TYPE_INT,
                           GTK_ARG_READWRITE, ARG_BYTESPERREAD);
  gtk_object_add_arg_type ("GstAsyncDiskSrc::offset", GTK_TYPE_LONG,
                           GTK_ARG_READWRITE, ARG_OFFSET);
  gtk_object_add_arg_type ("GstAsyncDiskSrc::size", GTK_TYPE_LONG,
                           GTK_ARG_READABLE, ARG_SIZE);

  gtkobject_class->set_arg = gst_asyncdisksrc_set_arg;
  gtkobject_class->get_arg = gst_asyncdisksrc_get_arg;

  gstelement_class->change_state = gst_asyncdisksrc_change_state;
}

static void 
gst_asyncdisksrc_init (GstAsyncDiskSrc *asyncdisksrc) 
{
//  GST_FLAG_SET (asyncdisksrc, GST_SRC_ASYNC);

  asyncdisksrc->srcpad = gst_pad_new ("src", GST_PAD_SRC);
  gst_pad_set_get_function (asyncdisksrc->srcpad,gst_asyncdisksrc_get);
  gst_pad_set_getregion_function (asyncdisksrc->srcpad,gst_asyncdisksrc_get_region);
  gst_element_add_pad (GST_ELEMENT (asyncdisksrc), asyncdisksrc->srcpad);

  asyncdisksrc->filename = NULL;
  asyncdisksrc->fd = 0;
  asyncdisksrc->size = 0;
  asyncdisksrc->map = NULL;
  asyncdisksrc->curoffset = 0;
  asyncdisksrc->bytes_per_read = 4096;
  asyncdisksrc->seq = 0;
  asyncdisksrc->new_seek = FALSE;
}


static void 
gst_asyncdisksrc_set_arg (GtkObject *object, GtkArg *arg, guint id) 
{
  GstAsyncDiskSrc *src;

  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_ASYNCDISKSRC (object));
  
  src = GST_ASYNCDISKSRC (object);

  switch(id) {
    case ARG_LOCATION:
      /* the element must be stopped in order to do this */
      g_return_if_fail (GST_STATE (src) < GST_STATE_PLAYING);

      if (src->filename) g_free (src->filename);
      /* clear the filename if we get a NULL (is that possible?) */
      if (GTK_VALUE_STRING (*arg) == NULL) {
        gst_element_set_state (GST_ELEMENT (object), GST_STATE_NULL);
        src->filename = NULL;
      /* otherwise set the new filename */
      } else {
        src->filename = g_strdup (GTK_VALUE_STRING (*arg));
      }
      break;
    case ARG_BYTESPERREAD:
      src->bytes_per_read = GTK_VALUE_INT (*arg);
      break;
    case ARG_OFFSET:
      src->curoffset = GTK_VALUE_LONG (*arg);
      src->new_seek = TRUE;
      break;
    default:
      break;
  }
}

static void 
gst_asyncdisksrc_get_arg (GtkObject *object, GtkArg *arg, guint id) 
{
  GstAsyncDiskSrc *src;

  /* it's not null if we got it, but it might not be ours */
  g_return_if_fail (GST_IS_ASYNCDISKSRC (object));
  
  src = GST_ASYNCDISKSRC (object);

  switch (id) {
    case ARG_LOCATION:
      GTK_VALUE_STRING (*arg) = src->filename;
      break;
    case ARG_BYTESPERREAD:
      GTK_VALUE_INT (*arg) = src->bytes_per_read;
      break;
    case ARG_OFFSET:
      GTK_VALUE_LONG (*arg) = src->curoffset;
      break;
    case ARG_SIZE:
      GTK_VALUE_LONG (*arg) = src->size;
      break;
    default:
      arg->type = GTK_TYPE_INVALID;
      break;
  }
}

/**
 * gst_asyncdisksrc_get:
 * @pad: #GstPad to push a buffer from
 *
 * Push a new buffer from the asyncdisksrc at the current offset.
 */
static GstBuffer *
gst_asyncdisksrc_get (GstPad *pad) 
{
  GstAsyncDiskSrc *src;
  GstBuffer *buf;

  g_return_val_if_fail (pad != NULL, NULL);
  src = GST_ASYNCDISKSRC (gst_pad_get_parent(pad));
  g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_ASYNCDISKSRC_OPEN), NULL);

  /* deal with EOF state */
  if (src->curoffset >= src->size) {
    gst_element_signal_eos (GST_ELEMENT (src));
    return NULL;
  }

  /* create the buffer */
  // FIXME: should eventually use a bufferpool for this
  buf = gst_buffer_new ();

  g_return_val_if_fail (buf != NULL, NULL);

  /* simply set the buffer to point to the correct region of the file */
  GST_BUFFER_DATA (buf) = src->map + src->curoffset;
  GST_BUFFER_OFFSET (buf) = src->curoffset;
  GST_BUFFER_FLAG_SET (buf, GST_BUFFER_DONTFREE);

  if ((src->curoffset + src->bytes_per_read) > src->size) {
    GST_BUFFER_SIZE (buf) = src->size - src->curoffset;
    // FIXME: set the buffer's EOF bit here
  } else
    GST_BUFFER_SIZE (buf) = src->bytes_per_read;

  GST_DEBUG (0,"map %p, offset %ld, size %d\n", src->map, src->curoffset, GST_BUFFER_SIZE (buf));

  //gst_util_dump_mem (GST_BUFFER_DATA (buf), GST_BUFFER_SIZE (buf));

  src->curoffset += GST_BUFFER_SIZE (buf);

  if (src->new_seek) {
    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLUSH);
    GST_DEBUG (0,"new seek\n");
    src->new_seek = FALSE;
  }

  /* we're done, return the buffer */
  return buf;
}

/**
 * gst_asyncdisksrc_get_region:
 * @src: #GstSrc to push a buffer from
 * @offset: offset in file
 * @size: number of bytes
 *
 * Push a new buffer from the asyncdisksrc of given size at given offset.
 */
static GstBuffer *
gst_asyncdisksrc_get_region (GstPad *pad, gulong offset, gulong size) 
{
  GstAsyncDiskSrc *src;
  GstBuffer *buf;

  g_return_val_if_fail (pad != NULL, NULL);

  src = GST_ASYNCDISKSRC (gst_pad_get_parent(pad));

  g_return_val_if_fail (GST_IS_ASYNCDISKSRC (src), NULL);
  g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_ASYNCDISKSRC_OPEN), NULL);
  
  /* deal with EOF state */
  if (offset >= src->size) {
    gst_element_signal_eos (GST_ELEMENT (src));
    return NULL;
  }

  /* create the buffer */
  // FIXME: should eventually use a bufferpool for this
  buf = gst_buffer_new ();
  g_return_val_if_fail (buf != NULL, NULL);

  /* simply set the buffer to point to the correct region of the file */
  GST_BUFFER_DATA (buf) = src->map + offset;
  GST_BUFFER_OFFSET (buf) = offset;
  GST_BUFFER_FLAG_SET (buf, GST_BUFFER_DONTFREE);

  if ((offset + size) > src->size) {
    GST_BUFFER_SIZE (buf) = src->size - offset;
    // FIXME: set the buffer's EOF bit here
  } else
    GST_BUFFER_SIZE (buf) = size;

  GST_DEBUG (0,"map %p, offset %ld, size %d\n", src->map, offset, GST_BUFFER_SIZE (buf));

  /* we're done, return the buffer off now */
  return buf;
}


/* open the file and mmap it, necessary to go to READY state */
static 
gboolean gst_asyncdisksrc_open_file (GstAsyncDiskSrc *src) 
{
  g_return_val_if_fail (!GST_FLAG_IS_SET (src ,GST_ASYNCDISKSRC_OPEN), FALSE);

  /* open the file */
  src->fd = open (src->filename, O_RDONLY);
  if (src->fd < 0) {
    perror ("open");
    gst_element_error (GST_ELEMENT (src), g_strconcat("opening file \"", src->filename, "\"", NULL));
    return FALSE;
  } else {
    /* find the file length */
    src->size = lseek (src->fd, 0, SEEK_END);
    lseek (src->fd, 0, SEEK_SET);
    /* map the file into memory */
    src->map = mmap (NULL, src->size, PROT_READ, MAP_SHARED, src->fd, 0);
    madvise (src->map,src->size, 2);
    /* collapse state if that failed */
    if (src->map == NULL) {
      close (src->fd);
      gst_element_error (GST_ELEMENT (src),"mmapping file");
      return FALSE;
    }
    GST_FLAG_SET (src, GST_ASYNCDISKSRC_OPEN);
    src->new_seek = TRUE;
  }
  return TRUE;
}

/* unmap and close the file */
static void 
gst_asyncdisksrc_close_file (GstAsyncDiskSrc *src) 
{
  g_return_if_fail (GST_FLAG_IS_SET (src, GST_ASYNCDISKSRC_OPEN));

  /* unmap the file from memory */
  munmap (src->map, src->size);
  /* close the file */
  close (src->fd);

  /* zero out a lot of our state */
  src->fd = 0;
  src->size = 0;
  src->map = NULL;
  src->curoffset = 0;
  src->seq = 0;
  src->new_seek = FALSE;

  GST_FLAG_UNSET (src, GST_ASYNCDISKSRC_OPEN);
}


static GstElementStateReturn 
gst_asyncdisksrc_change_state (GstElement *element) 
{
  g_return_val_if_fail (GST_IS_ASYNCDISKSRC (element), GST_STATE_FAILURE);

  if (GST_STATE_PENDING (element) == GST_STATE_NULL) {
    if (GST_FLAG_IS_SET (element, GST_ASYNCDISKSRC_OPEN))
      gst_asyncdisksrc_close_file (GST_ASYNCDISKSRC (element));
  } else {
    if (!GST_FLAG_IS_SET (element, GST_ASYNCDISKSRC_OPEN)) {
      if (!gst_asyncdisksrc_open_file (GST_ASYNCDISKSRC (element))) 
        return GST_STATE_FAILURE;
    }
  }

  if (GST_ELEMENT_CLASS (parent_class)->change_state)
    return GST_ELEMENT_CLASS (parent_class)->change_state (element);

  return GST_STATE_SUCCESS;
}