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added new gstfilesrc to replace disksrc eventually

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Original commit message from CVS:
added new gstfilesrc to replace disksrc eventually
This commit is contained in:
Erik Walthinsen 2001-08-22 04:30:27 +00:00
parent 12bbbd5c1e
commit 8f55a3b61f
6 changed files with 1108 additions and 0 deletions
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1
gst/elements/Makefile.am
View file

@ -15,6 +15,7 @@ libgstelements_la_SOURCES = \
gstidentity.c \
gstfakesink.c \
gstdisksrc.c \
gstfilesrc.c \
gstdisksink.c \
gstfdsrc.c \
gstfdsink.c \

6
gst/elements/gstelements.c
View file

@ -48,10 +48,16 @@ struct _elements_entry {
gboolean (*factoryinit) (GstElementFactory *factory);
};
extern GtkType gst_filesrc_get_type(void);
extern GstElementDetails *gst_filesrc_details;
static struct _elements_entry _elements[] = {
{ "fakesrc", gst_fakesrc_get_type, &gst_fakesrc_details, gst_fakesrc_factory_init },
{ "fakesink", gst_fakesink_get_type, &gst_fakesink_details, gst_fakesink_factory_init },
{ "disksrc", gst_disksrc_get_type, &gst_disksrc_details, NULL },
{ "filesrc", gst_filesrc_get_type, &gst_filesrc_details, NULL },
{ "disksink", gst_disksink_get_type, &gst_disksink_details, NULL },
{ "identity", gst_identity_get_type, &gst_identity_details, NULL },
{ "fdsink", gst_fdsink_get_type, &gst_fdsink_details, NULL },

547
gst/elements/gstfilesrc.c Normal file
View file

@ -0,0 +1,547 @@
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstfilesrc.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 <gst/gst.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
/**********************************************************************
* GStreamer Default File Source
* Theory of Operation
*
* This source uses mmap(2) to efficiently load data from a file.
* To do this without seriously polluting the applications' memory
* space, it must do so in smaller chunks, say 1-4MB at a time.
* Buffers are then subdivided from these mmap'd chunks, to directly
* make use of the mmap.
*
* To handle refcounting so that the mmap can be freed at the appropriate
* time, a buffer will be created for each mmap'd region, and all new
* buffers will be sub-buffers of this top-level buffer. As they are
* freed, the refcount goes down on the mmap'd buffer and its free()
* function is called, which will call munmap(2) on itself.
*
* If a buffer happens to cross the boundaries of an mmap'd region, we
* have to decide whether it's more efficient to copy the data into a
* new buffer, or mmap() just that buffer. There will have to be a
* breakpoint size to determine which will be done. The mmap() size
* has a lot to do with this as well, because you end up in double-
* jeopardy: the larger the outgoing buffer, the more data to copy when
* it overlaps, *and* the more frequently you'll have buffers that *do*
* overlap.
*
* Seeking is another tricky aspect to do efficiently. The initial
* implementation of this source won't make use of these features, however.
* The issue is that if an application seeks backwards in a file, *and*
* that region of the file is covered by an mmap that hasn't been fully
* deallocated, we really should re-use it. But keeping track of these
* regions is tricky because we have to lock the structure that holds
* them. We need to settle on a locking primitive (GMutex seems to be
* a really good option...), then we can do that.
*/
GstElementDetails gst_filesrc_details = {
"File Source",
"Source/File",
"Read from arbitrary point in a file",
VERSION,
"Erik Walthinsen <omega@cse.ogi.edu>",
"(C) 1999",
};
#define GST_TYPE_FILESRC \
(gst_filesrc_get_type())
#define GST_FILESRC(obj) \
(GTK_CHECK_CAST((obj),GST_TYPE_FILESRC,GstFileSrc))
#define GST_FILESRC_CLASS(klass) \
(GTK_CHECK_CLASS_CAST((klass),GST_TYPE_FILESRC,GstFileSrcClass))
#define GST_IS_FILESRC(obj) \
(GTK_CHECK_TYPE((obj),GST_TYPE_FILESRC))
#define GST_IS_FILESRC_CLASS(obj) \
(GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_FILESRC))
typedef enum {
GST_FILESRC_OPEN = GST_ELEMENT_FLAG_LAST,
GST_FILESRC_FLAG_LAST = GST_ELEMENT_FLAG_LAST + 2,
} GstFileSrcFlags;
typedef struct _GstFileSrc GstFileSrc;
typedef struct _GstFileSrcClass GstFileSrcClass;
struct _GstFileSrc {
GstElement element;
GstPad *srcpad;
gchar *filename; // filename
gint fd; // open file descriptor
off_t filelen; // what's the file length?
off_t curoffset; // current offset in file
off_t block_size; // bytes per read
GstBuffer *mapbuf;
off_t mapsize;
GTree *map_regions;
GMutex *map_regions_lock;
};
struct _GstFileSrcClass {
GstElementClass parent_class;
};
/* FileSrc signals and args */
enum {
/* FILL ME */
LAST_SIGNAL
};
enum {
ARG_0,
ARG_LOCATION,
ARG_BLOCKSIZE,
ARG_OFFSET,
ARG_SIZE,
};
static void gst_filesrc_class_init (GstFileSrcClass *klass);
static void gst_filesrc_init (GstFileSrc *filesrc);
static void gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id);
static void gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id);
static GstBuffer * gst_filesrc_get (GstPad *pad);
static GstElementStateReturn gst_filesrc_change_state (GstElement *element);
static GstElementClass *parent_class = NULL;
//static guint gst_filesrc_signals[LAST_SIGNAL] = { 0 };
GtkType
gst_filesrc_get_type(void)
{
static GtkType filesrc_type = 0;
if (!filesrc_type) {
static const GtkTypeInfo filesrc_info = {
"GstFileSrc",
sizeof(GstFileSrc),
sizeof(GstFileSrcClass),
(GtkClassInitFunc)gst_filesrc_class_init,
(GtkObjectInitFunc)gst_filesrc_init,
(GtkArgSetFunc)gst_filesrc_set_arg,
(GtkArgGetFunc)gst_filesrc_get_arg,
(GtkClassInitFunc)NULL,
};
filesrc_type = gtk_type_unique (GST_TYPE_ELEMENT, &filesrc_info);
}
return filesrc_type;
}
static void
gst_filesrc_class_init (GstFileSrcClass *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 ("GstFileSrc::location", GST_TYPE_FILENAME,
GTK_ARG_READWRITE, ARG_LOCATION);
gtk_object_add_arg_type ("GstFileSrc::blocksize", GTK_TYPE_INT,
GTK_ARG_READWRITE, ARG_BLOCKSIZE);
gtk_object_add_arg_type ("GstFileSrc::offset", GTK_TYPE_LONG,
GTK_ARG_READWRITE, ARG_OFFSET);
gtk_object_add_arg_type ("GstFileSrc::size", GTK_TYPE_LONG,
GTK_ARG_READABLE, ARG_SIZE);
gtkobject_class->set_arg = gst_filesrc_set_arg;
gtkobject_class->get_arg = gst_filesrc_get_arg;
gstelement_class->change_state = gst_filesrc_change_state;
}
static gint
gst_filesrc_bufcmp (gconstpointer a, gconstpointer b)
{
// GstBuffer *bufa = (GstBuffer *)a, *bufb = (GstBuffer *)b;
// sort first by offset, then in reverse by size
if (GST_BUFFER_OFFSET(a) < GST_BUFFER_OFFSET(b)) return -1;
else if (GST_BUFFER_OFFSET(a) > GST_BUFFER_OFFSET(b)) return 1;
else if (GST_BUFFER_SIZE(a) > GST_BUFFER_SIZE(b)) return -1;
else if (GST_BUFFER_SIZE(a) < GST_BUFFER_SIZE(b)) return 1;
else return 0;
}
static void
gst_filesrc_init (GstFileSrc *src)
{
src->srcpad = gst_pad_new ("src", GST_PAD_SRC);
gst_pad_set_get_function (src->srcpad,gst_filesrc_get);
gst_element_add_pad (GST_ELEMENT (src), src->srcpad);
src->filename = NULL;
src->fd = 0;
src->filelen = 0;
src->curoffset = 0;
src->block_size = 9216;
src->mapbuf = NULL;
src->mapsize = 1 * 1024 * 1024; // default is 1MB
src->map_regions = g_tree_new(gst_filesrc_bufcmp);
src->map_regions_lock = g_mutex_new();
}
static void
gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstFileSrc *src;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_FILESRC (object));
src = GST_FILESRC (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_BLOCKSIZE:
src->block_size = GTK_VALUE_INT (*arg);
break;
case ARG_OFFSET:
src->curoffset = GTK_VALUE_LONG (*arg);
break;
default:
break;
}
}
static void
gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstFileSrc *src;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_FILESRC (object));
src = GST_FILESRC (object);
switch (id) {
case ARG_LOCATION:
GTK_VALUE_STRING (*arg) = src->filename;
break;
case ARG_BLOCKSIZE:
GTK_VALUE_INT (*arg) = src->block_size;
break;
case ARG_OFFSET:
GTK_VALUE_LONG (*arg) = src->curoffset;
break;
case ARG_SIZE:
GTK_VALUE_LONG (*arg) = src->filelen;
break;
default:
arg->type = GTK_TYPE_INVALID;
break;
}
}
static void
gst_filesrc_free_parent_mmap (GstBuffer *buf)
{
GstFileSrc *src = GST_FILESRC(GST_BUFFER_POOL_PRIVATE(buf));
// remove the buffer from the list of available mmap'd regions
g_mutex_lock(src->map_regions_lock);
g_tree_remove(src->map_regions,buf);
// check to see if the tree is empty
if (g_tree_nnodes(src->map_regions) == 0) {
// we have to free the bufferpool we don't have yet
}
g_mutex_unlock(src->map_regions_lock);
// now unmap the memory
munmap(GST_BUFFER_DATA(buf),GST_BUFFER_MAXSIZE(buf));
}
static GstBuffer *
gst_filesrc_map_region (GstFileSrc *src, off_t offset, off_t size)
{
GstBuffer *buf;
GST_DEBUG(0, "mapping region %d+%d from file into memory\n",offset,size);
// time to allocate a new mapbuf
buf = gst_buffer_new();
// mmap() the data into this new buffer
GST_BUFFER_DATA(buf) = mmap (NULL, size, PROT_READ, MAP_SHARED, src->fd, offset);
if (GST_BUFFER_DATA(buf) == NULL) {
fprintf(stderr, "ERROR: gstfilesrc couldn't map file!\n");
} else if (GST_BUFFER_DATA(buf) == -1) {
perror("gstfilesrc:mmap()");
}
// fill in the rest of the fields
GST_BUFFER_FLAGS(buf) = GST_BUFFER_READONLY | GST_BUFFER_ORIGINAL;
GST_BUFFER_SIZE(buf) = size;
GST_BUFFER_MAXSIZE(buf) = size;
GST_BUFFER_OFFSET(buf) = offset;
GST_BUFFER_TIMESTAMP(buf) = -1LL;
GST_BUFFER_POOL_PRIVATE(buf) = src;
GST_BUFFER_FREE_FUNC(buf) = gst_filesrc_free_parent_mmap;
g_mutex_lock(src->map_regions_lock);
g_tree_insert(src->map_regions,buf,buf);
g_mutex_unlock(src->map_regions_lock);
return buf;
}
static GstBuffer *
gst_filesrc_map_small_region (GstFileSrc *src, off_t offset, off_t size)
{
gint pagesize = getpagesize();
int mod, mapbase, mapsize;
GstBuffer *map;
// printf("attempting to map a small buffer at %d+%d\n",offset,size);
// if the offset starts at a non-page boundary, we have to special case
if ((mod = offset % pagesize)) {
mapbase = offset - mod;
mapsize = (((mapbase + size + mod) + (pagesize - 1)) / pagesize) * pagesize - mapbase;
// printf("not on page boundaries, resizing map to %d+%d\n",mapbase,mapsize);
map = gst_filesrc_map_region(src, mapbase, mapsize);
return gst_buffer_create_sub (map, offset - mapbase, size);
}
return gst_filesrc_map_region(src,offset,size);
}
typedef struct {
off_t offset;
off_t size;
} GstFileSrcRegion;
// This allows us to search for a potential mmap region.
static gint
gst_filesrc_search_region_match (gpointer a, gpointer b)
{
GstFileSrcRegion *r = (GstFileSrcRegion *)b;
// trying to walk b down the tree, current node is a
if (r->offset < GST_BUFFER_OFFSET(a)) return -1;
else if (r->offset >= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 1;
else if ((r->offset + r->size) <= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 0;
return -2;
}
/**
* gst_filesrc_get:
* @pad: #GstPad to push a buffer from
*
* Push a new buffer from the filesrc at the current offset.
*/
static GstBuffer *
gst_filesrc_get (GstPad *pad)
{
GstFileSrc *src;
GstBuffer *buf = NULL, *map;
off_t readend,mapstart,mapend;
GstFileSrcRegion region;
g_return_val_if_fail (pad != NULL, NULL);
src = GST_FILESRC (gst_pad_get_parent (pad));
g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN), NULL);
// calculate end poiters so we don't have to do so repeatedly later
readend = src->curoffset + src->block_size; // note this is the byte *after* the read
mapstart = GST_BUFFER_OFFSET(src->mapbuf);
mapend = mapstart + GST_BUFFER_SIZE(src->mapbuf); // note this is the byte *after* the map
// if the start is past the mapstart
if (src->curoffset >= mapstart) {
// if the end is before the mapend, the buffer is in current mmap region...
// ('cause by definition if readend is in the buffer, so's readstart)
if (readend <= mapend) {
// printf("read buf %d+%d lives in current mapbuf %d+%d, creating subbuffer of mapbuf\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf),
src->block_size);
// if the start actually is within the current mmap region, map an overlap buffer
} else if (src->curoffset < mapend) {
// printf("read buf %d+%d starts in mapbuf %d+%d but ends outside, creating new mmap\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
}
// the only other option is that buffer is totally outside, which means we search for it
// now we can assume that the start is *before* the current mmap region
// if the readend is past mapstart, we have two options
} else if (readend >= mapstart) {
// either the read buffer overlaps the start of the mmap region
// or the read buffer fully contains the current mmap region
// either way, it's really not relevant, we just create a new region anyway
// printf("read buf %d+%d starts before mapbuf %d+%d, but overlaps it\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
}
// then deal with the case where the read buffer is totally outside
if (buf == NULL) {
// first check to see if there's a map that covers the right region already
// printf("searching for mapbuf to cover %d+%d\n",src->curoffset,src->block_size);
region.offset = src->curoffset;
region.size = src->block_size;
map = g_tree_search(src->map_regions,gst_filesrc_search_region_match,&region);
// if we found an exact match, subbuffer it
if (map != NULL) {
// printf("found mapbuf at %d+%d, creating subbuffer\n",GST_BUFFER_OFFSET(map),GST_BUFFER_SIZE(map));
buf = gst_buffer_create_sub (map, src->curoffset - GST_BUFFER_OFFSET(map), src->block_size);
// otherwise we need to create something out of thin air
} else {
// if the read buffer crosses a mmap region boundary, create a one-off region
if ((src->curoffset / src->mapsize) != ((src->curoffset + src->block_size) / src->mapsize)) {
// printf("read buf %d+%d crosses a %d-byte boundary, creating a one-off\n",
// src->curoffset,src->block_size,src->mapsize);
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
// otherwise we will create a new mmap region and set it to the default
} else {
off_t nextmap = src->curoffset - (src->curoffset % src->mapsize);
// printf("read buf %d+%d in new mapbuf at %d+%d, mapping and subbuffering\n",
// src->curoffset,src->block_size,nextmap,src->mapsize);
// first, we're done with the old mapbuf
gst_buffer_unref(src->mapbuf);
// create a new one
src->mapbuf = gst_filesrc_map_region (src, nextmap, src->mapsize);
// subbuffer it
buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf), src->block_size);
}
}
}
/* we're done, return the buffer */
src->curoffset += GST_BUFFER_SIZE(buf);
return buf;
}
/* open the file and mmap it, necessary to go to READY state */
static gboolean
gst_filesrc_open_file (GstFileSrc *src)
{
g_return_val_if_fail (!GST_FLAG_IS_SET (src ,GST_FILESRC_OPEN), FALSE);
GST_DEBUG(0, "opening file %s\n",src->filename);
/* 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->filelen = lseek (src->fd, 0, SEEK_END);
lseek (src->fd, 0, SEEK_SET);
// allocate the first mmap'd region
src->mapbuf = gst_filesrc_map_region (src, 0, src->mapsize);
src->curoffset = 0;
GST_FLAG_SET (src, GST_FILESRC_OPEN);
}
return TRUE;
}
/* unmap and close the file */
static void
gst_filesrc_close_file (GstFileSrc *src)
{
g_return_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN));
/* close the file */
close (src->fd);
/* zero out a lot of our state */
src->fd = 0;
src->filelen = 0;
src->curoffset = 0;
GST_FLAG_UNSET (src, GST_FILESRC_OPEN);
}
static GstElementStateReturn
gst_filesrc_change_state (GstElement *element)
{
g_return_val_if_fail (GST_IS_FILESRC (element), GST_STATE_FAILURE);
if (GST_STATE_PENDING (element) == GST_STATE_NULL) {
if (GST_FLAG_IS_SET (element, GST_FILESRC_OPEN))
gst_filesrc_close_file (GST_FILESRC (element));
} else {
if (!GST_FLAG_IS_SET (element, GST_FILESRC_OPEN)) {
if (!gst_filesrc_open_file (GST_FILESRC (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;
}

1
plugins/elements/Makefile.am
View file

@ -15,6 +15,7 @@ libgstelements_la_SOURCES = \
gstidentity.c \
gstfakesink.c \
gstdisksrc.c \
gstfilesrc.c \
gstdisksink.c \
gstfdsrc.c \
gstfdsink.c \

6
plugins/elements/gstelements.c
View file

@ -48,10 +48,16 @@ struct _elements_entry {
gboolean (*factoryinit) (GstElementFactory *factory);
};
extern GtkType gst_filesrc_get_type(void);
extern GstElementDetails *gst_filesrc_details;
static struct _elements_entry _elements[] = {
{ "fakesrc", gst_fakesrc_get_type, &gst_fakesrc_details, gst_fakesrc_factory_init },
{ "fakesink", gst_fakesink_get_type, &gst_fakesink_details, gst_fakesink_factory_init },
{ "disksrc", gst_disksrc_get_type, &gst_disksrc_details, NULL },
{ "filesrc", gst_filesrc_get_type, &gst_filesrc_details, NULL },
{ "disksink", gst_disksink_get_type, &gst_disksink_details, NULL },
{ "identity", gst_identity_get_type, &gst_identity_details, NULL },
{ "fdsink", gst_fdsink_get_type, &gst_fdsink_details, NULL },

547
plugins/elements/gstfilesrc.c Normal file
View file

@ -0,0 +1,547 @@
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstfilesrc.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 <gst/gst.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
/**********************************************************************
* GStreamer Default File Source
* Theory of Operation
*
* This source uses mmap(2) to efficiently load data from a file.
* To do this without seriously polluting the applications' memory
* space, it must do so in smaller chunks, say 1-4MB at a time.
* Buffers are then subdivided from these mmap'd chunks, to directly
* make use of the mmap.
*
* To handle refcounting so that the mmap can be freed at the appropriate
* time, a buffer will be created for each mmap'd region, and all new
* buffers will be sub-buffers of this top-level buffer. As they are
* freed, the refcount goes down on the mmap'd buffer and its free()
* function is called, which will call munmap(2) on itself.
*
* If a buffer happens to cross the boundaries of an mmap'd region, we
* have to decide whether it's more efficient to copy the data into a
* new buffer, or mmap() just that buffer. There will have to be a
* breakpoint size to determine which will be done. The mmap() size
* has a lot to do with this as well, because you end up in double-
* jeopardy: the larger the outgoing buffer, the more data to copy when
* it overlaps, *and* the more frequently you'll have buffers that *do*
* overlap.
*
* Seeking is another tricky aspect to do efficiently. The initial
* implementation of this source won't make use of these features, however.
* The issue is that if an application seeks backwards in a file, *and*
* that region of the file is covered by an mmap that hasn't been fully
* deallocated, we really should re-use it. But keeping track of these
* regions is tricky because we have to lock the structure that holds
* them. We need to settle on a locking primitive (GMutex seems to be
* a really good option...), then we can do that.
*/
GstElementDetails gst_filesrc_details = {
"File Source",
"Source/File",
"Read from arbitrary point in a file",
VERSION,
"Erik Walthinsen <omega@cse.ogi.edu>",
"(C) 1999",
};
#define GST_TYPE_FILESRC \
(gst_filesrc_get_type())
#define GST_FILESRC(obj) \
(GTK_CHECK_CAST((obj),GST_TYPE_FILESRC,GstFileSrc))
#define GST_FILESRC_CLASS(klass) \
(GTK_CHECK_CLASS_CAST((klass),GST_TYPE_FILESRC,GstFileSrcClass))
#define GST_IS_FILESRC(obj) \
(GTK_CHECK_TYPE((obj),GST_TYPE_FILESRC))
#define GST_IS_FILESRC_CLASS(obj) \
(GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_FILESRC))
typedef enum {
GST_FILESRC_OPEN = GST_ELEMENT_FLAG_LAST,
GST_FILESRC_FLAG_LAST = GST_ELEMENT_FLAG_LAST + 2,
} GstFileSrcFlags;
typedef struct _GstFileSrc GstFileSrc;
typedef struct _GstFileSrcClass GstFileSrcClass;
struct _GstFileSrc {
GstElement element;
GstPad *srcpad;
gchar *filename; // filename
gint fd; // open file descriptor
off_t filelen; // what's the file length?
off_t curoffset; // current offset in file
off_t block_size; // bytes per read
GstBuffer *mapbuf;
off_t mapsize;
GTree *map_regions;
GMutex *map_regions_lock;
};
struct _GstFileSrcClass {
GstElementClass parent_class;
};
/* FileSrc signals and args */
enum {
/* FILL ME */
LAST_SIGNAL
};
enum {
ARG_0,
ARG_LOCATION,
ARG_BLOCKSIZE,
ARG_OFFSET,
ARG_SIZE,
};
static void gst_filesrc_class_init (GstFileSrcClass *klass);
static void gst_filesrc_init (GstFileSrc *filesrc);
static void gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id);
static void gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id);
static GstBuffer * gst_filesrc_get (GstPad *pad);
static GstElementStateReturn gst_filesrc_change_state (GstElement *element);
static GstElementClass *parent_class = NULL;
//static guint gst_filesrc_signals[LAST_SIGNAL] = { 0 };
GtkType
gst_filesrc_get_type(void)
{
static GtkType filesrc_type = 0;
if (!filesrc_type) {
static const GtkTypeInfo filesrc_info = {
"GstFileSrc",
sizeof(GstFileSrc),
sizeof(GstFileSrcClass),
(GtkClassInitFunc)gst_filesrc_class_init,
(GtkObjectInitFunc)gst_filesrc_init,
(GtkArgSetFunc)gst_filesrc_set_arg,
(GtkArgGetFunc)gst_filesrc_get_arg,
(GtkClassInitFunc)NULL,
};
filesrc_type = gtk_type_unique (GST_TYPE_ELEMENT, &filesrc_info);
}
return filesrc_type;
}
static void
gst_filesrc_class_init (GstFileSrcClass *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 ("GstFileSrc::location", GST_TYPE_FILENAME,
GTK_ARG_READWRITE, ARG_LOCATION);
gtk_object_add_arg_type ("GstFileSrc::blocksize", GTK_TYPE_INT,
GTK_ARG_READWRITE, ARG_BLOCKSIZE);
gtk_object_add_arg_type ("GstFileSrc::offset", GTK_TYPE_LONG,
GTK_ARG_READWRITE, ARG_OFFSET);
gtk_object_add_arg_type ("GstFileSrc::size", GTK_TYPE_LONG,
GTK_ARG_READABLE, ARG_SIZE);
gtkobject_class->set_arg = gst_filesrc_set_arg;
gtkobject_class->get_arg = gst_filesrc_get_arg;
gstelement_class->change_state = gst_filesrc_change_state;
}
static gint
gst_filesrc_bufcmp (gconstpointer a, gconstpointer b)
{
// GstBuffer *bufa = (GstBuffer *)a, *bufb = (GstBuffer *)b;
// sort first by offset, then in reverse by size
if (GST_BUFFER_OFFSET(a) < GST_BUFFER_OFFSET(b)) return -1;
else if (GST_BUFFER_OFFSET(a) > GST_BUFFER_OFFSET(b)) return 1;
else if (GST_BUFFER_SIZE(a) > GST_BUFFER_SIZE(b)) return -1;
else if (GST_BUFFER_SIZE(a) < GST_BUFFER_SIZE(b)) return 1;
else return 0;
}
static void
gst_filesrc_init (GstFileSrc *src)
{
src->srcpad = gst_pad_new ("src", GST_PAD_SRC);
gst_pad_set_get_function (src->srcpad,gst_filesrc_get);
gst_element_add_pad (GST_ELEMENT (src), src->srcpad);
src->filename = NULL;
src->fd = 0;
src->filelen = 0;
src->curoffset = 0;
src->block_size = 9216;
src->mapbuf = NULL;
src->mapsize = 1 * 1024 * 1024; // default is 1MB
src->map_regions = g_tree_new(gst_filesrc_bufcmp);
src->map_regions_lock = g_mutex_new();
}
static void
gst_filesrc_set_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstFileSrc *src;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_FILESRC (object));
src = GST_FILESRC (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_BLOCKSIZE:
src->block_size = GTK_VALUE_INT (*arg);
break;
case ARG_OFFSET:
src->curoffset = GTK_VALUE_LONG (*arg);
break;
default:
break;
}
}
static void
gst_filesrc_get_arg (GtkObject *object, GtkArg *arg, guint id)
{
GstFileSrc *src;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail (GST_IS_FILESRC (object));
src = GST_FILESRC (object);
switch (id) {
case ARG_LOCATION:
GTK_VALUE_STRING (*arg) = src->filename;
break;
case ARG_BLOCKSIZE:
GTK_VALUE_INT (*arg) = src->block_size;
break;
case ARG_OFFSET:
GTK_VALUE_LONG (*arg) = src->curoffset;
break;
case ARG_SIZE:
GTK_VALUE_LONG (*arg) = src->filelen;
break;
default:
arg->type = GTK_TYPE_INVALID;
break;
}
}
static void
gst_filesrc_free_parent_mmap (GstBuffer *buf)
{
GstFileSrc *src = GST_FILESRC(GST_BUFFER_POOL_PRIVATE(buf));
// remove the buffer from the list of available mmap'd regions
g_mutex_lock(src->map_regions_lock);
g_tree_remove(src->map_regions,buf);
// check to see if the tree is empty
if (g_tree_nnodes(src->map_regions) == 0) {
// we have to free the bufferpool we don't have yet
}
g_mutex_unlock(src->map_regions_lock);
// now unmap the memory
munmap(GST_BUFFER_DATA(buf),GST_BUFFER_MAXSIZE(buf));
}
static GstBuffer *
gst_filesrc_map_region (GstFileSrc *src, off_t offset, off_t size)
{
GstBuffer *buf;
GST_DEBUG(0, "mapping region %d+%d from file into memory\n",offset,size);
// time to allocate a new mapbuf
buf = gst_buffer_new();
// mmap() the data into this new buffer
GST_BUFFER_DATA(buf) = mmap (NULL, size, PROT_READ, MAP_SHARED, src->fd, offset);
if (GST_BUFFER_DATA(buf) == NULL) {
fprintf(stderr, "ERROR: gstfilesrc couldn't map file!\n");
} else if (GST_BUFFER_DATA(buf) == -1) {
perror("gstfilesrc:mmap()");
}
// fill in the rest of the fields
GST_BUFFER_FLAGS(buf) = GST_BUFFER_READONLY | GST_BUFFER_ORIGINAL;
GST_BUFFER_SIZE(buf) = size;
GST_BUFFER_MAXSIZE(buf) = size;
GST_BUFFER_OFFSET(buf) = offset;
GST_BUFFER_TIMESTAMP(buf) = -1LL;
GST_BUFFER_POOL_PRIVATE(buf) = src;
GST_BUFFER_FREE_FUNC(buf) = gst_filesrc_free_parent_mmap;
g_mutex_lock(src->map_regions_lock);
g_tree_insert(src->map_regions,buf,buf);
g_mutex_unlock(src->map_regions_lock);
return buf;
}
static GstBuffer *
gst_filesrc_map_small_region (GstFileSrc *src, off_t offset, off_t size)
{
gint pagesize = getpagesize();
int mod, mapbase, mapsize;
GstBuffer *map;
// printf("attempting to map a small buffer at %d+%d\n",offset,size);
// if the offset starts at a non-page boundary, we have to special case
if ((mod = offset % pagesize)) {
mapbase = offset - mod;
mapsize = (((mapbase + size + mod) + (pagesize - 1)) / pagesize) * pagesize - mapbase;
// printf("not on page boundaries, resizing map to %d+%d\n",mapbase,mapsize);
map = gst_filesrc_map_region(src, mapbase, mapsize);
return gst_buffer_create_sub (map, offset - mapbase, size);
}
return gst_filesrc_map_region(src,offset,size);
}
typedef struct {
off_t offset;
off_t size;
} GstFileSrcRegion;
// This allows us to search for a potential mmap region.
static gint
gst_filesrc_search_region_match (gpointer a, gpointer b)
{
GstFileSrcRegion *r = (GstFileSrcRegion *)b;
// trying to walk b down the tree, current node is a
if (r->offset < GST_BUFFER_OFFSET(a)) return -1;
else if (r->offset >= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 1;
else if ((r->offset + r->size) <= (GST_BUFFER_OFFSET(a) + GST_BUFFER_SIZE(a))) return 0;
return -2;
}
/**
* gst_filesrc_get:
* @pad: #GstPad to push a buffer from
*
* Push a new buffer from the filesrc at the current offset.
*/
static GstBuffer *
gst_filesrc_get (GstPad *pad)
{
GstFileSrc *src;
GstBuffer *buf = NULL, *map;
off_t readend,mapstart,mapend;
GstFileSrcRegion region;
g_return_val_if_fail (pad != NULL, NULL);
src = GST_FILESRC (gst_pad_get_parent (pad));
g_return_val_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN), NULL);
// calculate end poiters so we don't have to do so repeatedly later
readend = src->curoffset + src->block_size; // note this is the byte *after* the read
mapstart = GST_BUFFER_OFFSET(src->mapbuf);
mapend = mapstart + GST_BUFFER_SIZE(src->mapbuf); // note this is the byte *after* the map
// if the start is past the mapstart
if (src->curoffset >= mapstart) {
// if the end is before the mapend, the buffer is in current mmap region...
// ('cause by definition if readend is in the buffer, so's readstart)
if (readend <= mapend) {
// printf("read buf %d+%d lives in current mapbuf %d+%d, creating subbuffer of mapbuf\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf),
src->block_size);
// if the start actually is within the current mmap region, map an overlap buffer
} else if (src->curoffset < mapend) {
// printf("read buf %d+%d starts in mapbuf %d+%d but ends outside, creating new mmap\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
}
// the only other option is that buffer is totally outside, which means we search for it
// now we can assume that the start is *before* the current mmap region
// if the readend is past mapstart, we have two options
} else if (readend >= mapstart) {
// either the read buffer overlaps the start of the mmap region
// or the read buffer fully contains the current mmap region
// either way, it's really not relevant, we just create a new region anyway
// printf("read buf %d+%d starts before mapbuf %d+%d, but overlaps it\n",
// src->curoffset,src->block_size,GST_BUFFER_OFFSET(src->mapbuf),GST_BUFFER_SIZE(src->mapbuf));
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
}
// then deal with the case where the read buffer is totally outside
if (buf == NULL) {
// first check to see if there's a map that covers the right region already
// printf("searching for mapbuf to cover %d+%d\n",src->curoffset,src->block_size);
region.offset = src->curoffset;
region.size = src->block_size;
map = g_tree_search(src->map_regions,gst_filesrc_search_region_match,&region);
// if we found an exact match, subbuffer it
if (map != NULL) {
// printf("found mapbuf at %d+%d, creating subbuffer\n",GST_BUFFER_OFFSET(map),GST_BUFFER_SIZE(map));
buf = gst_buffer_create_sub (map, src->curoffset - GST_BUFFER_OFFSET(map), src->block_size);
// otherwise we need to create something out of thin air
} else {
// if the read buffer crosses a mmap region boundary, create a one-off region
if ((src->curoffset / src->mapsize) != ((src->curoffset + src->block_size) / src->mapsize)) {
// printf("read buf %d+%d crosses a %d-byte boundary, creating a one-off\n",
// src->curoffset,src->block_size,src->mapsize);
buf = gst_filesrc_map_small_region (src, src->curoffset, src->block_size);
// otherwise we will create a new mmap region and set it to the default
} else {
off_t nextmap = src->curoffset - (src->curoffset % src->mapsize);
// printf("read buf %d+%d in new mapbuf at %d+%d, mapping and subbuffering\n",
// src->curoffset,src->block_size,nextmap,src->mapsize);
// first, we're done with the old mapbuf
gst_buffer_unref(src->mapbuf);
// create a new one
src->mapbuf = gst_filesrc_map_region (src, nextmap, src->mapsize);
// subbuffer it
buf = gst_buffer_create_sub (src->mapbuf, src->curoffset - GST_BUFFER_OFFSET(src->mapbuf), src->block_size);
}
}
}
/* we're done, return the buffer */
src->curoffset += GST_BUFFER_SIZE(buf);
return buf;
}
/* open the file and mmap it, necessary to go to READY state */
static gboolean
gst_filesrc_open_file (GstFileSrc *src)
{
g_return_val_if_fail (!GST_FLAG_IS_SET (src ,GST_FILESRC_OPEN), FALSE);
GST_DEBUG(0, "opening file %s\n",src->filename);
/* 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->filelen = lseek (src->fd, 0, SEEK_END);
lseek (src->fd, 0, SEEK_SET);
// allocate the first mmap'd region
src->mapbuf = gst_filesrc_map_region (src, 0, src->mapsize);
src->curoffset = 0;
GST_FLAG_SET (src, GST_FILESRC_OPEN);
}
return TRUE;
}
/* unmap and close the file */
static void
gst_filesrc_close_file (GstFileSrc *src)
{
g_return_if_fail (GST_FLAG_IS_SET (src, GST_FILESRC_OPEN));
/* close the file */
close (src->fd);
/* zero out a lot of our state */
src->fd = 0;
src->filelen = 0;
src->curoffset = 0;
GST_FLAG_UNSET (src, GST_FILESRC_OPEN);
}
static GstElementStateReturn
gst_filesrc_change_state (GstElement *element)
{
g_return_val_if_fail (GST_IS_FILESRC (element), GST_STATE_FAILURE);
if (GST_STATE_PENDING (element) == GST_STATE_NULL) {
if (GST_FLAG_IS_SET (element, GST_FILESRC_OPEN))
gst_filesrc_close_file (GST_FILESRC (element));
} else {
if (!GST_FLAG_IS_SET (element, GST_FILESRC_OPEN)) {
if (!gst_filesrc_open_file (GST_FILESRC (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;
}