2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 #include "gstfilesrc.h"
35 /**********************************************************************
36 * GStreamer Default File Source
39 * This source uses mmap(2) to efficiently load data from a file.
40 * To do this without seriously polluting the applications' memory
41 * space, it must do so in smaller chunks, say 1-4MB at a time.
42 * Buffers are then subdivided from these mmap'd chunks, to directly
43 * make use of the mmap.
45 * To handle refcounting so that the mmap can be freed at the appropriate
46 * time, a buffer will be created for each mmap'd region, and all new
47 * buffers will be sub-buffers of this top-level buffer. As they are
48 * freed, the refcount goes down on the mmap'd buffer and its free()
49 * function is called, which will call munmap(2) on itself.
51 * If a buffer happens to cross the boundaries of an mmap'd region, we
52 * have to decide whether it's more efficient to copy the data into a
53 * new buffer, or mmap() just that buffer. There will have to be a
54 * breakpoint size to determine which will be done. The mmap() size
55 * has a lot to do with this as well, because you end up in double-
56 * jeopardy: the larger the outgoing buffer, the more data to copy when
57 * it overlaps, *and* the more frequently you'll have buffers that *do*
60 * Seeking is another tricky aspect to do efficiently. The initial
61 * implementation of this source won't make use of these features, however.
62 * The issue is that if an application seeks backwards in a file, *and*
63 * that region of the file is covered by an mmap that hasn't been fully
64 * deallocated, we really should re-use it. But keeping track of these
65 * regions is tricky because we have to lock the structure that holds
66 * them. We need to settle on a locking primitive (GMutex seems to be
67 * a really good option...), then we can do that.
71 GstElementDetails gst_filesrc_details = {
74 "Read from arbitrary point in a file",
76 "Erik Walthinsen <omega@cse.ogi.edu>",
80 //#define fs_print(format,args...) g_print(format, ## args)
81 #define fs_print(format,args...)
83 /* FileSrc signals and args */
101 static void gst_filesrc_class_init (GstFileSrcClass *klass);
102 static void gst_filesrc_init (GstFileSrc *filesrc);
104 static void gst_filesrc_set_property (GObject *object, guint prop_id,
105 const GValue *value, GParamSpec *pspec);
106 static void gst_filesrc_get_property (GObject *object, guint prop_id,
107 GValue *value, GParamSpec *pspec);
109 static GstBuffer * gst_filesrc_get (GstPad *pad);
110 static gboolean gst_filesrc_srcpad_event (GstPad *pad, GstEvent *event);
112 static GstElementStateReturn gst_filesrc_change_state (GstElement *element);
115 static GstElementClass *parent_class = NULL;
116 //static guint gst_filesrc_signals[LAST_SIGNAL] = { 0 };
119 gst_filesrc_get_type(void)
121 static GType filesrc_type = 0;
124 static const GTypeInfo filesrc_info = {
125 sizeof(GstFileSrcClass), NULL,
127 (GClassInitFunc)gst_filesrc_class_init,
132 (GInstanceInitFunc)gst_filesrc_init,
134 filesrc_type = g_type_register_static (GST_TYPE_ELEMENT, "GstFileSrc", &filesrc_info, 0);
140 gst_filesrc_class_init (GstFileSrcClass *klass)
142 GObjectClass *gobject_class;
143 GstElementClass *gstelement_class;
145 gobject_class = (GObjectClass*)klass;
146 gstelement_class = (GstElementClass*)klass;
148 parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
150 gst_element_install_std_props (
151 GST_ELEMENT_CLASS (klass),
152 "fd", ARG_FD, G_PARAM_READABLE,
153 "offset", ARG_OFFSET, G_PARAM_READWRITE,
154 "filesize", ARG_FILESIZE, G_PARAM_READABLE,
155 "location", ARG_LOCATION, G_PARAM_READWRITE,
156 "blocksize", ARG_BLOCKSIZE, G_PARAM_READWRITE,
157 "mmapsize", ARG_MAPSIZE, G_PARAM_READWRITE,
158 "touch", ARG_TOUCH, G_PARAM_READWRITE,
161 gobject_class->set_property = gst_filesrc_set_property;
162 gobject_class->get_property = gst_filesrc_get_property;
164 gstelement_class->change_state = gst_filesrc_change_state;
168 gst_filesrc_bufcmp (gconstpointer a, gconstpointer b)
170 // GstBuffer *bufa = (GstBuffer *)a, *bufb = (GstBuffer *)b;
172 // sort first by offset, then in reverse by size
173 if (GST_BUFFER_OFFSET(a) < GST_BUFFER_OFFSET(b)) return -1;
174 else if (GST_BUFFER_OFFSET(a) > GST_BUFFER_OFFSET(b)) return 1;
175 else if (GST_BUFFER_SIZE(a) > GST_BUFFER_SIZE(b)) return -1;
176 else if (GST_BUFFER_SIZE(a) < GST_BUFFER_SIZE(b)) return 1;
181 gst_filesrc_init (GstFileSrc *src)
183 src->srcpad = gst_pad_new ("src", GST_PAD_SRC);
184 gst_pad_set_get_function (src->srcpad,gst_filesrc_get);
185 gst_pad_set_event_function (src->srcpad,gst_filesrc_srcpad_event);
186 gst_element_add_pad (GST_ELEMENT (src), src->srcpad);
188 src->pagesize = getpagesize();
190 src->filename = NULL;
195 src->block_size = 4096;
199 src->mapsize = 4 * 1024 * 1024; // default is 4MB
201 src->map_regions = g_tree_new(gst_filesrc_bufcmp);
202 src->map_regions_lock = g_mutex_new();
204 src->seek_happened = FALSE;
209 gst_filesrc_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
213 /* it's not null if we got it, but it might not be ours */
214 g_return_if_fail (GST_IS_FILESRC (object));
216 src = GST_FILESRC (object);
220 /* the element must be stopped in order to do this */
221 g_return_if_fail (GST_STATE (src) < GST_STATE_PLAYING);
223 if (src->filename) g_free (src->filename);
224 /* clear the filename if we get a NULL (is that possible?) */
225 if (g_value_get_string (value) == NULL) {
226 gst_element_set_state (GST_ELEMENT (object), GST_STATE_NULL);
227 src->filename = NULL;
228 /* otherwise set the new filename */
230 src->filename = g_strdup (g_value_get_string (value));
234 src->block_size = g_value_get_ulong (value);
237 src->curoffset = g_value_get_int64 (value);
240 if ((src->mapsize % src->pagesize) == 0)
241 src->mapsize = g_value_get_ulong (value);
243 GST_INFO(0, "invalid mapsize, must a multiple of pagesize, which is %d\n",src->pagesize);
246 src->touch = g_value_get_boolean (value);
254 gst_filesrc_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
258 /* it's not null if we got it, but it might not be ours */
259 g_return_if_fail (GST_IS_FILESRC (object));
261 src = GST_FILESRC (object);
265 g_value_set_string (value, src->filename);
268 g_value_set_int64 (value, src->filelen);
271 g_value_set_int (value, src->fd);
274 g_value_set_ulong (value, src->block_size);
277 g_value_set_int64 (value, src->curoffset);
280 g_value_set_ulong (value, src->mapsize);
283 g_value_set_boolean (value, src->touch);
286 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
292 gst_filesrc_free_parent_mmap (GstBuffer *buf)
294 GstFileSrc *src = GST_FILESRC(GST_BUFFER_POOL_PRIVATE(buf));
296 fs_print ("freeing mmap()d buffer at %d+%d\n",GST_BUFFER_OFFSET(buf),GST_BUFFER_SIZE(buf));
298 // remove the buffer from the list of available mmap'd regions
299 g_mutex_lock(src->map_regions_lock);
300 g_tree_remove(src->map_regions,buf);
301 // check to see if the tree is empty
302 if (g_tree_nnodes(src->map_regions) == 0) {
303 // we have to free the bufferpool we don't have yet
305 g_mutex_unlock(src->map_regions_lock);
308 // madvise to tell the kernel what to do with it
309 madvise(GST_BUFFER_DATA(buf),GST_BUFFER_SIZE(buf),MADV_DONTNEED);
311 // now unmap the memory
312 munmap(GST_BUFFER_DATA(buf),GST_BUFFER_MAXSIZE(buf));
316 gst_filesrc_map_region (GstFileSrc *src, off_t offset, size_t size)
321 g_return_val_if_fail (offset >= 0, NULL);
323 fs_print ("mapping region %08lx+%08lx from file into memory\n",offset,size);
325 // time to allocate a new mapbuf
326 buf = gst_buffer_new();
327 // mmap() the data into this new buffer
328 GST_BUFFER_DATA(buf) = mmap (NULL, size, PROT_READ, MAP_SHARED, src->fd, offset);
329 if (GST_BUFFER_DATA(buf) == NULL) {
330 fprintf (stderr, "ERROR: gstfilesrc couldn't map file!\n");
331 } else if (GST_BUFFER_DATA(buf) == MAP_FAILED) {
332 g_error ("gstfilesrc mmap(0x%x, %d, 0x%llx) : %s",
333 size, src->fd, offset, sys_errlist[errno]);
335 #ifdef MADV_SEQUENTIAL
336 // madvise to tell the kernel what to do with it
337 retval = madvise(GST_BUFFER_DATA(buf),GST_BUFFER_SIZE(buf),MADV_SEQUENTIAL);
339 // fill in the rest of the fields
340 GST_BUFFER_FLAGS(buf) = GST_BUFFER_READONLY | GST_BUFFER_ORIGINAL;
341 GST_BUFFER_SIZE(buf) = size;
342 GST_BUFFER_MAXSIZE(buf) = size;
343 GST_BUFFER_OFFSET(buf) = offset;
344 GST_BUFFER_TIMESTAMP(buf) = -1LL;
345 GST_BUFFER_POOL_PRIVATE(buf) = src;
346 GST_BUFFER_FREE_FUNC(buf) = gst_filesrc_free_parent_mmap;
348 g_mutex_lock(src->map_regions_lock);
349 g_tree_insert(src->map_regions,buf,buf);
350 g_mutex_unlock(src->map_regions_lock);
356 gst_filesrc_map_small_region (GstFileSrc *src, off_t offset, size_t size)
362 // printf("attempting to map a small buffer at %d+%d\n",offset,size);
364 // if the offset starts at a non-page boundary, we have to special case
365 if ((mod = offset % src->pagesize)) {
368 mapbase = offset - mod;
369 mapsize = ((size + mod + src->pagesize - 1) / src->pagesize) * src->pagesize;
370 // printf("not on page boundaries, resizing map to %d+%d\n",mapbase,mapsize);
371 map = gst_filesrc_map_region(src, mapbase, mapsize);
372 ret = gst_buffer_create_sub (map, offset - mapbase, size);
374 gst_buffer_unref (map);
379 return gst_filesrc_map_region(src,offset,size);
387 // This allows us to search for a potential mmap region.
389 gst_filesrc_search_region_match (gpointer a, gpointer b)
391 GstFileSrcRegion *r = (GstFileSrcRegion *)b;
393 // trying to walk b down the tree, current node is a
394 if (r->offset < GST_BUFFER_OFFSET(a)) return -1;
395 else if (r->offset >= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 1;
396 else if ((r->offset + r->size) <= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 0;
403 * @pad: #GstPad to push a buffer from
405 * Push a new buffer from the filesrc at the current offset.
408 gst_filesrc_get (GstPad *pad)
411 GstBuffer *buf = NULL, *map;
413 off_t readend,mapstart,mapend;
414 GstFileSrcRegion region;
417 g_return_val_if_fail (pad != NULL, NULL);
418 src = GST_FILESRC (gst_pad_get_parent (pad));
419 g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN), NULL);
422 if (src->seek_happened) {
423 src->seek_happened = FALSE;
424 return GST_BUFFER (gst_event_new(GST_EVENT_DISCONTINUOUS));
428 if (src->curoffset == src->filelen) {
429 gst_element_set_state (GST_ELEMENT (src), GST_STATE_PAUSED);
430 return GST_BUFFER (gst_event_new(GST_EVENT_EOS));
433 // calculate end pointers so we don't have to do so repeatedly later
434 readsize = src->block_size;
435 readend = src->curoffset + src->block_size; // note this is the byte *after* the read
436 mapstart = GST_BUFFER_OFFSET(src->mapbuf);
437 mapend = mapstart + GST_BUFFER_SIZE(src->mapbuf); // note this is the byte *after* the map
439 // check to see if we're going to overflow the end of the file
440 if (readend > src->filelen) {
441 readsize = src->filelen - src->curoffset;
442 readend = src->curoffset;
445 // if the start is past the mapstart
446 if (src->curoffset >= mapstart) {
447 // if the end is before the mapend, the buffer is in current mmap region...
448 // ('cause by definition if readend is in the buffer, so's readstart)
449 if (readend <= mapend) {
450 fs_print ("read buf %d+%d lives in current mapbuf %d+%d, creating subbuffer of mapbuf\n",
451 src->curoffset,readsize,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
452 buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf),
455 // if the start actually is within the current mmap region, map an overlap buffer
456 } else if (src->curoffset < mapend) {
457 fs_print ("read buf %d+%d starts in mapbuf %d+%d but ends outside, creating new mmap\n",
458 src->curoffset,readsize,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
459 buf = gst_filesrc_map_small_region (src, src->curoffset, readsize);
462 // the only other option is that buffer is totally outside, which means we search for it
464 // now we can assume that the start is *before* the current mmap region
465 // if the readend is past mapstart, we have two options
466 } else if (readend >= mapstart) {
467 // either the read buffer overlaps the start of the mmap region
468 // or the read buffer fully contains the current mmap region
469 // either way, it's really not relevant, we just create a new region anyway
470 fs_print ("read buf %d+%d starts before mapbuf %d+%d, but overlaps it\n",
471 src->curoffset,readsize,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
472 buf = gst_filesrc_map_small_region (src, src->curoffset, readsize);
475 // then deal with the case where the read buffer is totally outside
477 // first check to see if there's a map that covers the right region already
478 fs_print ("searching for mapbuf to cover %d+%d\n",src->curoffset,readsize);
479 region.offset = src->curoffset;
480 region.size = readsize;
481 map = g_tree_search (src->map_regions,
482 (GCompareFunc) gst_filesrc_search_region_match,
485 // if we found an exact match, subbuffer it
487 fs_print ("found mapbuf at %d+%d, creating subbuffer\n",GST_BUFFER_OFFSET(map),GST_BUFFER_SIZE(map));
488 buf = gst_buffer_create_sub (map, src->curoffset - GST_BUFFER_OFFSET(map), readsize);
490 // otherwise we need to create something out of thin air
492 // if the read buffer crosses a mmap region boundary, create a one-off region
493 if ((src->curoffset / src->mapsize) != (readend / src->mapsize)) {
494 fs_print ("read buf %d+%d crosses a %d-byte boundary, creating a one-off\n",
495 src->curoffset,readsize,src->mapsize);
496 buf = gst_filesrc_map_small_region (src, src->curoffset, readsize);
498 // otherwise we will create a new mmap region and set it to the default
500 off_t nextmap = src->curoffset - (src->curoffset % src->mapsize);
501 fs_print ("read buf %d+%d in new mapbuf at %d+%d, mapping and subbuffering\n",
502 src->curoffset,readsize,nextmap,src->mapsize);
503 // first, we're done with the old mapbuf
504 gst_buffer_unref(src->mapbuf);
506 src->mapbuf = gst_filesrc_map_region (src, nextmap, src->mapsize);
508 buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf), readsize);
513 /* if we need to touch the buffer (to bring it into memory), do so */
515 volatile guchar *p = GST_BUFFER_DATA (buf), c;
516 for (i=0;i<GST_BUFFER_SIZE(buf);i+=src->pagesize)
520 /* we're done, return the buffer */
521 src->curoffset += GST_BUFFER_SIZE(buf);
525 /* open the file and mmap it, necessary to go to READY state */
527 gst_filesrc_open_file (GstFileSrc *src)
529 g_return_val_if_fail (!GST_FLAG_IS_SET (src ,GST_FILESRC_OPEN), FALSE);
531 GST_DEBUG(0, "opening file %s\n",src->filename);
534 src->fd = open (src->filename, O_RDONLY);
537 gst_element_error (GST_ELEMENT (src), g_strconcat("opening file \"", src->filename, "\"", NULL));
540 /* find the file length */
541 src->filelen = lseek (src->fd, 0, SEEK_END);
542 lseek (src->fd, 0, SEEK_SET);
544 // allocate the first mmap'd region
545 src->mapbuf = gst_filesrc_map_region (src, 0, src->mapsize);
549 GST_FLAG_SET (src, GST_FILESRC_OPEN);
554 /* unmap and close the file */
556 gst_filesrc_close_file (GstFileSrc *src)
558 g_return_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN));
564 /* zero out a lot of our state */
569 GST_FLAG_UNSET (src, GST_FILESRC_OPEN);
573 static GstElementStateReturn
574 gst_filesrc_change_state (GstElement *element)
576 g_return_val_if_fail (GST_IS_FILESRC (element), GST_STATE_FAILURE);
578 if (GST_STATE_PENDING (element) == GST_STATE_NULL) {
579 if (GST_FLAG_IS_SET (element, GST_FILESRC_OPEN))
580 gst_filesrc_close_file (GST_FILESRC (element));
582 if (!GST_FLAG_IS_SET (element, GST_FILESRC_OPEN)) {
583 if (!gst_filesrc_open_file (GST_FILESRC (element)))
584 return GST_STATE_FAILURE;
588 if (GST_ELEMENT_CLASS (parent_class)->change_state)
589 return GST_ELEMENT_CLASS (parent_class)->change_state (element);
591 return GST_STATE_SUCCESS;
595 gst_filesrc_srcpad_event (GstPad *pad, GstEvent *event)
597 GstFileSrc *src = GST_FILESRC(GST_PAD_PARENT(pad));
599 switch (GST_EVENT_TYPE (event)) {
601 src->curoffset = (guint64) GST_EVENT_SEEK_OFFSET (event);
602 src->seek_happened = TRUE;
603 gst_event_free (event);
604 // push a discontinuous event?