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 <sys/types.h>
32 /**********************************************************************
33 * GStreamer Default File Source
36 * This source uses mmap(2) to efficiently load data from a file.
37 * To do this without seriously polluting the applications' memory
38 * space, it must do so in smaller chunks, say 1-4MB at a time.
39 * Buffers are then subdivided from these mmap'd chunks, to directly
40 * make use of the mmap.
42 * To handle refcounting so that the mmap can be freed at the appropriate
43 * time, a buffer will be created for each mmap'd region, and all new
44 * buffers will be sub-buffers of this top-level buffer. As they are
45 * freed, the refcount goes down on the mmap'd buffer and its free()
46 * function is called, which will call munmap(2) on itself.
48 * If a buffer happens to cross the boundaries of an mmap'd region, we
49 * have to decide whether it's more efficient to copy the data into a
50 * new buffer, or mmap() just that buffer. There will have to be a
51 * breakpoint size to determine which will be done. The mmap() size
52 * has a lot to do with this as well, because you end up in double-
53 * jeopardy: the larger the outgoing buffer, the more data to copy when
54 * it overlaps, *and* the more frequently you'll have buffers that *do*
57 * Seeking is another tricky aspect to do efficiently. The initial
58 * implementation of this source won't make use of these features, however.
59 * The issue is that if an application seeks backwards in a file, *and*
60 * that region of the file is covered by an mmap that hasn't been fully
61 * deallocated, we really should re-use it. But keeping track of these
62 * regions is tricky because we have to lock the structure that holds
63 * them. We need to settle on a locking primitive (GMutex seems to be
64 * a really good option...), then we can do that.
68 GstElementDetails gst_filesrc_details = {
71 "Read from arbitrary point in a file",
73 "Erik Walthinsen <omega@cse.ogi.edu>",
78 #define GST_TYPE_FILESRC \
79 (gst_filesrc_get_type())
80 #define GST_FILESRC(obj) \
81 (GTK_CHECK_CAST((obj),GST_TYPE_FILESRC,GstFileSrc))
82 #define GST_FILESRC_CLASS(klass) \
83 (GTK_CHECK_CLASS_CAST((klass),GST_TYPE_FILESRC,GstFileSrcClass))
84 #define GST_IS_FILESRC(obj) \
85 (GTK_CHECK_TYPE((obj),GST_TYPE_FILESRC))
86 #define GST_IS_FILESRC_CLASS(obj) \
87 (GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_FILESRC))
90 GST_FILESRC_OPEN = GST_ELEMENT_FLAG_LAST,
92 GST_FILESRC_FLAG_LAST = GST_ELEMENT_FLAG_LAST + 2,
95 typedef struct _GstFileSrc GstFileSrc;
96 typedef struct _GstFileSrcClass GstFileSrcClass;
102 gchar *filename; // filename
103 gint fd; // open file descriptor
104 off_t filelen; // what's the file length?
106 off_t curoffset; // current offset in file
107 off_t block_size; // bytes per read
113 GMutex *map_regions_lock;
116 struct _GstFileSrcClass {
117 GstElementClass parent_class;
121 /* FileSrc signals and args */
136 static void gst_filesrc_class_init (GstFileSrcClass *klass);
137 static void gst_filesrc_init (GstFileSrc *filesrc);
139 static void gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id);
140 static void gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id);
142 static GstBuffer * gst_filesrc_get (GstPad *pad);
144 static GstElementStateReturn gst_filesrc_change_state (GstElement *element);
147 static GstElementClass *parent_class = NULL;
148 //static guint gst_filesrc_signals[LAST_SIGNAL] = { 0 };
151 gst_filesrc_get_type(void)
153 static GtkType filesrc_type = 0;
156 static const GtkTypeInfo filesrc_info = {
159 sizeof(GstFileSrcClass),
160 (GtkClassInitFunc)gst_filesrc_class_init,
161 (GtkObjectInitFunc)gst_filesrc_init,
162 (GtkArgSetFunc)gst_filesrc_set_arg,
163 (GtkArgGetFunc)gst_filesrc_get_arg,
164 (GtkClassInitFunc)NULL,
166 filesrc_type = gtk_type_unique (GST_TYPE_ELEMENT, &filesrc_info);
172 gst_filesrc_class_init (GstFileSrcClass *klass)
174 GtkObjectClass *gtkobject_class;
175 GstElementClass *gstelement_class;
177 gtkobject_class = (GtkObjectClass*)klass;
178 gstelement_class = (GstElementClass*)klass;
180 parent_class = gtk_type_class (GST_TYPE_ELEMENT);
182 gtk_object_add_arg_type ("GstFileSrc::location", GST_TYPE_FILENAME,
183 GTK_ARG_READWRITE, ARG_LOCATION);
184 gtk_object_add_arg_type ("GstFileSrc::blocksize", GTK_TYPE_INT,
185 GTK_ARG_READWRITE, ARG_BLOCKSIZE);
186 gtk_object_add_arg_type ("GstFileSrc::offset", GTK_TYPE_LONG,
187 GTK_ARG_READWRITE, ARG_OFFSET);
188 gtk_object_add_arg_type ("GstFileSrc::size", GTK_TYPE_LONG,
189 GTK_ARG_READABLE, ARG_SIZE);
191 gtkobject_class->set_arg = gst_filesrc_set_arg;
192 gtkobject_class->get_arg = gst_filesrc_get_arg;
194 gstelement_class->change_state = gst_filesrc_change_state;
198 gst_filesrc_bufcmp (gconstpointer a, gconstpointer b)
200 // GstBuffer *bufa = (GstBuffer *)a, *bufb = (GstBuffer *)b;
202 // sort first by offset, then in reverse by size
203 if (GST_BUFFER_OFFSET(a) < GST_BUFFER_OFFSET(b)) return -1;
204 else if (GST_BUFFER_OFFSET(a) > GST_BUFFER_OFFSET(b)) return 1;
205 else if (GST_BUFFER_SIZE(a) > GST_BUFFER_SIZE(b)) return -1;
206 else if (GST_BUFFER_SIZE(a) < GST_BUFFER_SIZE(b)) return 1;
211 gst_filesrc_init (GstFileSrc *src)
213 src->srcpad = gst_pad_new ("src", GST_PAD_SRC);
214 gst_pad_set_get_function (src->srcpad,gst_filesrc_get);
215 gst_element_add_pad (GST_ELEMENT (src), src->srcpad);
217 src->filename = NULL;
222 src->block_size = 9216;
225 src->mapsize = 1 * 1024 * 1024; // default is 1MB
227 src->map_regions = g_tree_new(gst_filesrc_bufcmp);
228 src->map_regions_lock = g_mutex_new();
233 gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id)
237 /* it's not null if we got it, but it might not be ours */
238 g_return_if_fail (GST_IS_FILESRC (object));
240 src = GST_FILESRC (object);
244 /* the element must be stopped in order to do this */
245 g_return_if_fail (GST_STATE (src) < GST_STATE_PLAYING);
247 if (src->filename) g_free (src->filename);
248 /* clear the filename if we get a NULL (is that possible?) */
249 if (GTK_VALUE_STRING (*arg) == NULL) {
250 gst_element_set_state (GST_ELEMENT (object), GST_STATE_NULL);
251 src->filename = NULL;
252 /* otherwise set the new filename */
254 src->filename = g_strdup (GTK_VALUE_STRING (*arg));
258 src->block_size = GTK_VALUE_INT (*arg);
261 src->curoffset = GTK_VALUE_LONG (*arg);
269 gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id)
273 /* it's not null if we got it, but it might not be ours */
274 g_return_if_fail (GST_IS_FILESRC (object));
276 src = GST_FILESRC (object);
280 GTK_VALUE_STRING (*arg) = src->filename;
283 GTK_VALUE_INT (*arg) = src->block_size;
286 GTK_VALUE_LONG (*arg) = src->curoffset;
289 GTK_VALUE_LONG (*arg) = src->filelen;
292 arg->type = GTK_TYPE_INVALID;
298 gst_filesrc_free_parent_mmap (GstBuffer *buf)
300 GstFileSrc *src = GST_FILESRC(GST_BUFFER_POOL_PRIVATE(buf));
302 // remove the buffer from the list of available mmap'd regions
303 g_mutex_lock(src->map_regions_lock);
304 g_tree_remove(src->map_regions,buf);
305 // check to see if the tree is empty
306 if (g_tree_nnodes(src->map_regions) == 0) {
307 // we have to free the bufferpool we don't have yet
309 g_mutex_unlock(src->map_regions_lock);
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, off_t size)
320 GST_DEBUG(0, "mapping region %d+%d from file into memory\n",offset,size);
322 // time to allocate a new mapbuf
323 buf = gst_buffer_new();
324 // mmap() the data into this new buffer
325 GST_BUFFER_DATA(buf) = mmap (NULL, size, PROT_READ, MAP_SHARED, src->fd, offset);
326 if (GST_BUFFER_DATA(buf) == NULL) {
327 fprintf(stderr, "ERROR: gstfilesrc couldn't map file!\n");
328 } else if (GST_BUFFER_DATA(buf) == -1) {
329 perror("gstfilesrc:mmap()");
331 // fill in the rest of the fields
332 GST_BUFFER_FLAGS(buf) = GST_BUFFER_READONLY | GST_BUFFER_ORIGINAL;
333 GST_BUFFER_SIZE(buf) = size;
334 GST_BUFFER_MAXSIZE(buf) = size;
335 GST_BUFFER_OFFSET(buf) = offset;
336 GST_BUFFER_TIMESTAMP(buf) = -1LL;
337 GST_BUFFER_POOL_PRIVATE(buf) = src;
338 GST_BUFFER_FREE_FUNC(buf) = gst_filesrc_free_parent_mmap;
340 g_mutex_lock(src->map_regions_lock);
341 g_tree_insert(src->map_regions,buf,buf);
342 g_mutex_unlock(src->map_regions_lock);
348 gst_filesrc_map_small_region (GstFileSrc *src, off_t offset, off_t size)
350 gint pagesize = getpagesize();
351 int mod, mapbase, mapsize;
354 // printf("attempting to map a small buffer at %d+%d\n",offset,size);
356 // if the offset starts at a non-page boundary, we have to special case
357 if ((mod = offset % pagesize)) {
358 mapbase = offset - mod;
359 mapsize = (((mapbase + size + mod) + (pagesize - 1)) / pagesize) * pagesize - mapbase;
360 // printf("not on page boundaries, resizing map to %d+%d\n",mapbase,mapsize);
361 map = gst_filesrc_map_region(src, mapbase, mapsize);
362 return gst_buffer_create_sub (map, offset - mapbase, size);
365 return gst_filesrc_map_region(src,offset,size);
373 // This allows us to search for a potential mmap region.
375 gst_filesrc_search_region_match (gpointer a, gpointer b)
377 GstFileSrcRegion *r = (GstFileSrcRegion *)b;
379 // trying to walk b down the tree, current node is a
380 if (r->offset < GST_BUFFER_OFFSET(a)) return -1;
381 else if (r->offset >= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 1;
382 else if ((r->offset + r->size) <= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 0;
389 * @pad: #GstPad to push a buffer from
391 * Push a new buffer from the filesrc at the current offset.
394 gst_filesrc_get (GstPad *pad)
397 GstBuffer *buf = NULL, *map;
398 off_t readend,mapstart,mapend;
399 GstFileSrcRegion region;
401 g_return_val_if_fail (pad != NULL, NULL);
402 src = GST_FILESRC (gst_pad_get_parent (pad));
403 g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN), NULL);
405 // calculate end poiters so we don't have to do so repeatedly later
406 readend = src->curoffset + src->block_size; // note this is the byte *after* the read
407 mapstart = GST_BUFFER_OFFSET(src->mapbuf);
408 mapend = mapstart + GST_BUFFER_SIZE(src->mapbuf); // note this is the byte *after* the map
410 // if the start is past the mapstart
411 if (src->curoffset >= mapstart) {
412 // if the end is before the mapend, the buffer is in current mmap region...
413 // ('cause by definition if readend is in the buffer, so's readstart)
414 if (readend <= mapend) {
415 // printf("read buf %d+%d lives in current mapbuf %d+%d, creating subbuffer of mapbuf\n",
416 // src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
417 buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf),
420 // if the start actually is within the current mmap region, map an overlap buffer
421 } else if (src->curoffset < mapend) {
422 // printf("read buf %d+%d starts in mapbuf %d+%d but ends outside, creating new mmap\n",
423 // src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
424 buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
427 // the only other option is that buffer is totally outside, which means we search for it
429 // now we can assume that the start is *before* the current mmap region
430 // if the readend is past mapstart, we have two options
431 } else if (readend >= mapstart) {
432 // either the read buffer overlaps the start of the mmap region
433 // or the read buffer fully contains the current mmap region
434 // either way, it's really not relevant, we just create a new region anyway
435 // printf("read buf %d+%d starts before mapbuf %d+%d, but overlaps it\n",
436 // src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
437 buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
440 // then deal with the case where the read buffer is totally outside
442 // first check to see if there's a map that covers the right region already
443 // printf("searching for mapbuf to cover %d+%d\n",src->curoffset,src->block_size);
444 region.offset = src->curoffset;
445 region.size = src->block_size;
446 map = g_tree_search(src->map_regions,gst_filesrc_search_region_match,®ion);
448 // if we found an exact match, subbuffer it
450 // printf("found mapbuf at %d+%d, creating subbuffer\n",GST_BUFFER_OFFSET(map),GST_BUFFER_SIZE(map));
451 buf = gst_buffer_create_sub (map, src->curoffset - GST_BUFFER_OFFSET(map), src->block_size);
453 // otherwise we need to create something out of thin air
455 // if the read buffer crosses a mmap region boundary, create a one-off region
456 if ((src->curoffset / src->mapsize) != ((src->curoffset + src->block_size) / src->mapsize)) {
457 // printf("read buf %d+%d crosses a %d-byte boundary, creating a one-off\n",
458 // src->curoffset,src->block_size,src->mapsize);
459 buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
461 // otherwise we will create a new mmap region and set it to the default
463 off_t nextmap = src->curoffset - (src->curoffset % src->mapsize);
464 // printf("read buf %d+%d in new mapbuf at %d+%d, mapping and subbuffering\n",
465 // src->curoffset,src->block_size,nextmap,src->mapsize);
466 // first, we're done with the old mapbuf
467 gst_buffer_unref(src->mapbuf);
469 src->mapbuf = gst_filesrc_map_region (src, nextmap, src->mapsize);
471 buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf), src->block_size);
476 /* we're done, return the buffer */
477 src->curoffset += GST_BUFFER_SIZE(buf);
481 /* open the file and mmap it, necessary to go to READY state */
483 gst_filesrc_open_file (GstFileSrc *src)
485 g_return_val_if_fail (!GST_FLAG_IS_SET (src ,GST_FILESRC_OPEN), FALSE);
487 GST_DEBUG(0, "opening file %s\n",src->filename);
490 src->fd = open (src->filename, O_RDONLY);
493 gst_element_error (GST_ELEMENT (src), g_strconcat("opening file \"", src->filename, "\"", NULL));
496 /* find the file length */
497 src->filelen = lseek (src->fd, 0, SEEK_END);
498 lseek (src->fd, 0, SEEK_SET);
500 // allocate the first mmap'd region
501 src->mapbuf = gst_filesrc_map_region (src, 0, src->mapsize);
505 GST_FLAG_SET (src, GST_FILESRC_OPEN);
510 /* unmap and close the file */
512 gst_filesrc_close_file (GstFileSrc *src)
514 g_return_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN));
519 /* zero out a lot of our state */
524 GST_FLAG_UNSET (src, GST_FILESRC_OPEN);
528 static GstElementStateReturn
529 gst_filesrc_change_state (GstElement *element)
531 g_return_val_if_fail (GST_IS_FILESRC (element), GST_STATE_FAILURE);
533 if (GST_STATE_PENDING (element) == GST_STATE_NULL) {
534 if (GST_FLAG_IS_SET (element, GST_FILESRC_OPEN))
535 gst_filesrc_close_file (GST_FILESRC (element));
537 if (!GST_FLAG_IS_SET (element, GST_FILESRC_OPEN)) {
538 if (!gst_filesrc_open_file (GST_FILESRC (element)))
539 return GST_STATE_FAILURE;
543 if (GST_ELEMENT_CLASS (parent_class)->change_state)
544 return GST_ELEMENT_CLASS (parent_class)->change_state (element);
546 return GST_STATE_SUCCESS;