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Renamed bytestream2 to bytestream again, the previous implementation sucked anyway.

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Original commit message from CVS:
Renamed bytestream2 to bytestream again, the previous implementation
sucked anyway.
This commit is contained in:
Wim Taymans 2001-09-21 19:25:28 +00:00
parent f443469504
commit 73dbfbffe1
6 changed files with 315 additions and 505 deletions
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4
libs/bytestream/Makefile.am
View file

@ -2,10 +2,10 @@ filterdir = $(libdir)/gst
filter_LTLIBRARIES = libgstbytestream.la libgstbstest.la filter_LTLIBRARIES = libgstbytestream.la libgstbstest.la
libgstbytestream_la_SOURCES = gstbytestream.c gstbytestream2.c libgstbytestream_la_SOURCES = gstbytestream.c
libgstbstest_la_SOURCES = gstbstest.c libgstbstest_la_SOURCES = gstbstest.c
libgstbytestreamincludedir = $(includedir)/gst/libs/bytestream libgstbytestreamincludedir = $(includedir)/gst/libs/bytestream
libgstbytestreaminclude_HEADERS = gstbytestream.h gstbytestream2.h libgstbytestreaminclude_HEADERS = gstbytestream.h
# CFLAGS += -O2 $(FOMIT_FRAME_POINTER) -funroll-all-loops -finline-functions -ffast-math # CFLAGS += -O2 $(FOMIT_FRAME_POINTER) -funroll-all-loops -finline-functions -ffast-math

18
libs/bytestream/gstbstest.c
View file

@ -21,7 +21,7 @@
*/ */
#include <gst/gst.h> #include <gst/gst.h>
#include "gstbytestream2.h" #include "gstbytestream.h"
#define GST_TYPE_IDENTITY \ #define GST_TYPE_IDENTITY \
(gst_identity_get_type()) (gst_identity_get_type())
@ -43,7 +43,7 @@ struct _GstIdentity {
GstPad *sinkpad; GstPad *sinkpad;
GstPad *srcpad; GstPad *srcpad;
GstByteStream2 *bs; GstByteStream *bs;
gint byte_size; gint byte_size;
gint count; gint count;
}; };
@ -56,9 +56,9 @@ GType gst_identity_get_type(void);
GstElementDetails gst_identity_details = { GstElementDetails gst_identity_details = {
"ByteStream2Test", "ByteStreamTest",
"Filter", "Filter",
"Test for the GstByteStream2 code", "Test for the GstByteStream code",
VERSION, VERSION,
"Erik Walthinsen <omega@temple-baptist.com>", "Erik Walthinsen <omega@temple-baptist.com>",
"(C) 2001", "(C) 2001",
@ -166,7 +166,7 @@ gst_identity_init (GstIdentity *identity)
identity->byte_size = 384; identity->byte_size = 384;
identity->count = 5; identity->count = 5;
identity->bs = gst_bytestream2_new(identity->sinkpad); identity->bs = gst_bytestream_new(identity->sinkpad);
} }
static void static void
@ -187,12 +187,12 @@ gst_identity_loop (GstElement *element)
for (i=0;i<identity->count;i++) { for (i=0;i<identity->count;i++) {
// g_print("bstest: getting a buffer of %d bytes\n",identity->byte_size); // g_print("bstest: getting a buffer of %d bytes\n",identity->byte_size);
buf = gst_bytestream2_read(identity->bs,identity->byte_size); buf = gst_bytestream_read(identity->bs,identity->byte_size);
if (!buf) g_print("BUFFER IS BOGUS\n"); if (!buf) g_print("BUFFER IS BOGUS\n");
// g_print("pushing the buffer, %d bytes at %d\n",GST_BUFFER_SIZE(buf),GST_BUFFER_OFFSET(buf)); // g_print("pushing the buffer, %d bytes at %d\n",GST_BUFFER_SIZE(buf),GST_BUFFER_OFFSET(buf));
gst_pad_push(identity->srcpad,buf); gst_pad_push(identity->srcpad,buf);
// g_print("\n"); // g_print("\n");
gst_bytestream2_print_status(identity->bs); gst_bytestream_print_status(identity->bs);
// g_print("\n\n"); // g_print("\n\n");
} }
@ -205,11 +205,11 @@ gst_identity_loop (GstElement *element)
for (i=0;i<identity->count;i++) { for (i=0;i<identity->count;i++) {
buf = gst_buffer_new(); buf = gst_buffer_new();
// note that this is dangerous, as it does *NOT* refcount the data, it can go away!!! // note that this is dangerous, as it does *NOT* refcount the data, it can go away!!!
GST_BUFFER_DATA(buf) = gst_bytestream2_peek_bytes(identity->bs,identity->byte_size); GST_BUFFER_DATA(buf) = gst_bytestream_peek_bytes(identity->bs,identity->byte_size);
GST_BUFFER_SIZE(buf) = identity->byte_size; GST_BUFFER_SIZE(buf) = identity->byte_size;
GST_BUFFER_FLAG_SET(buf,GST_BUFFER_DONTFREE); GST_BUFFER_FLAG_SET(buf,GST_BUFFER_DONTFREE);
gst_pad_push(identity->srcpad,buf); gst_pad_push(identity->srcpad,buf);
gst_bytestream2_flush(identity->bs,identity->byte_size); gst_bytestream_flush(identity->bs,identity->byte_size);
} }
exit(1); exit(1);

393
libs/bytestream/gstbytestream.c
View file

@ -1,25 +1,3 @@
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstbytestreams.c: Utility functions: gtk_get_property stuff, etc.
*
* 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 <stdio.h> #include <stdio.h>
#include <string.h> #include <string.h>
#include <stdlib.h> #include <stdlib.h>
@ -27,128 +5,343 @@
#include <gst/gstinfo.h> #include <gst/gstinfo.h>
#include "gstbytestream.h" #include "gstbytestream.h"
//#define bs_print(format,args...) g_print(format, ## args)
#define bs_print(format,args...)
//static void gst_bytestream_print_status(GstByteStream *bs);
guint8 *gst_bytestream_assemble (GstByteStream * bs, guint32 len);
/** /**
* gst_bytestream_new: * gst_bytestream_new:
* @pad: the pad to attach the bytstream to * @pad: the pad to attach the bytestream to
* *
* creates a bytestream from the given pad * creates a bytestream from the given pad
* *
* Returns: a new #GstByteStream object * Returns: a new #GstByteStream object
*/ */
GstByteStream* GstByteStream *
gst_bytestream_new (GstPad *pad) gst_bytestream_new (GstPad * pad)
{ {
GstByteStream *bs = g_new (GstByteStream, 1); GstByteStream *bs = g_new (GstByteStream, 1);
bs->pad = pad; bs->pad = pad;
bs->buffer = NULL;
bs->index = 0; bs->buflist = NULL;
bs->pos = 0; bs->headbufavail = 0;
bs->size = 0; bs->listavail = 0;
return bs; return bs;
} }
void void
gst_bytestream_destroy (GstByteStream *bs) gst_bytestream_destroy (GstByteStream * bs)
{ {
if (bs->buffer) { // FIXME lots of cleaning up to do here...
gst_buffer_unref (bs->buffer);
}
g_free (bs); g_free (bs);
} }
static inline guint64 // HOW THIS WORKS:
gst_bytestream_fill (GstByteStream *bs, guint64 len) //
// The fundamental structure is a singly-linked list of buffers. The
// buffer on the front is the oldest, and thus the first to read data
// from. The number of bytes left to be read in this buffer is stored
// in bs->headbufavail. The number of bytes available in the entire
// list (including the head buffer) is in bs->listavail.
//
// When a request is made for data (peek), _fill_bytes is called with
// the number of bytes needed, but only if the listavail indicates
// that there aren't already enough. This calls _get_next_buf until
// the listavail is sufficient to satisfy the demand.
//
// _get_next_buf pulls a buffer from the pad the bytestream is attached
// to, and shoves it in the list. There are actually two things it can
// do. If there's already a buffer in the list, and the _is_span_fast()
// test returns true, it will merge it with that last buffer. Otherwise
// it will simply tack it onto the end of the list.
//
// The _peek itself first checks the simple case of the request fitting
// within the head buffer, and if so creates a subbuffer and returns.
// Otherwise, it creates a new buffer and allocates space for the request
// and calls _assemble to fill it. We know we have to copy because this
// case only happens when the _merge wasn't feasible during _get_next_buf.
//
// The _flush method repeatedly inspects the head buffer and flushes as
// much data from it as it needs to, up to the size of the buffer. If
// the flush decimates the buffer, it's stripped, unref'd, and removed.
// get the next buffer
// if the buffer can be merged with the head buffer, do so
// else add it onto the head of the
static gboolean
gst_bytestream_get_next_buf (GstByteStream * bs)
{ {
GstBuffer *buf; GstBuffer *nextbuf, *lastbuf;
GSList *end;
g_print ("fill %08llx %08llx\n", len, bs->pos); bs_print ("get_next_buf: pulling buffer\n");
nextbuf = gst_pad_pull (bs->pad);
bs_print ("get_next_buf: got buffer of %d bytes\n", GST_BUFFER_SIZE (nextbuf));
while ((bs->index + len) > bs->size) { // first see if there are any buffers in the list at all
buf = gst_pad_pull (bs->pad); if (bs->buflist) {
bs_print ("gst_next_buf: there is at least one buffer in the list\n");
// now find the end of the list
end = g_slist_last (bs->buflist);
// get the buffer that's there
lastbuf = GST_BUFFER (end->data);
if (!bs->buffer) { // see if we can marge cheaply
bs->buffer = buf; if (gst_buffer_is_span_fast (lastbuf, nextbuf)) {
bs_print ("get_next_buf: merging new buffer with last buf on list\n");
// it is, let's merge them (this is really an append, but...)
end->data = gst_buffer_merge (lastbuf, nextbuf);
// add to the length of the list
bs->listavail += GST_BUFFER_SIZE (nextbuf);
// have to check to see if we merged with the head buffer
if (end == bs->buflist) {
bs->headbufavail += GST_BUFFER_SIZE (nextbuf);
}
// we can ditch the nextbuf then
gst_buffer_unref (nextbuf);
// if we can't, we just append this buffer
} }
else { else {
bs->buffer = gst_buffer_merge (bs->buffer, buf); bs_print ("get_next_buf: adding new buffer to the end of the list\n");
} end = g_slist_append (end, nextbuf);
bs->size = GST_BUFFER_SIZE (bs->buffer); // also need to increment length of list and buffer count
bs->listavail += GST_BUFFER_SIZE (nextbuf);
} }
return len; // if there are no buffers in the list
}
else {
bs_print ("get_next_buf: buflist is empty, adding new buffer to list\n");
// put this on the end of the list
bs->buflist = g_slist_append (bs->buflist, nextbuf);
// and increment the number of bytes in the list
bs->listavail = GST_BUFFER_SIZE (nextbuf);
// set the head buffer avail to the size
bs->headbufavail = GST_BUFFER_SIZE (nextbuf);
}
return TRUE;
} }
static inline void
gst_bytestream_shrink (GstByteStream *bs, guint64 len) static gboolean
gst_bytestream_fill_bytes (GstByteStream * bs, guint32 len)
{ {
GstBuffer *newbuf; // as long as we don't have enough, we get more buffers
while (bs->listavail < len) {
bs->index += len; bs_print ("fill_bytes: there are %d bytes in the list, we need %d\n", bs->listavail, len);
bs->pos += len; gst_bytestream_get_next_buf (bs);
if ((GST_BUFFER_SIZE (bs->buffer) - bs->index) > 1024 * 1024) {
g_print ("shrink%08llx %08llx, %08llx\n", len, bs->pos,
GST_BUFFER_SIZE (bs->buffer) - bs->index);
newbuf = gst_buffer_create_sub (bs->buffer, bs->index,
GST_BUFFER_SIZE (bs->buffer) - bs->index);
bs->size = GST_BUFFER_SIZE (newbuf);
gst_buffer_unref (bs->buffer);
bs->index = 0;
bs->buffer = newbuf;
} }
return TRUE;
} }
GstBuffer*
gst_bytestream_peek (GstByteStream *bs, guint64 len) GstBuffer *
gst_bytestream_peek (GstByteStream * bs, guint32 len)
{ {
GstBuffer *headbuf, *retbuf = NULL;
g_return_val_if_fail (bs != NULL, NULL);
g_return_val_if_fail (len > 0, NULL);
bs_print ("peek: asking for %d bytes\n", len);
// make sure we have enough
bs_print ("peek: there are %d bytes in the list\n", bs->listavail);
if (len > bs->listavail) {
gst_bytestream_fill_bytes (bs, len);
bs_print ("peek: there are now %d bytes in the list\n", bs->listavail);
}
gst_bytestream_print_status (bs);
// extract the head buffer
headbuf = GST_BUFFER (bs->buflist->data);
// if the requested bytes are in the current buffer
bs_print ("peek: headbufavail is %d\n", bs->headbufavail);
if (len <= bs->headbufavail) {
bs_print ("peek: there are enough bytes in headbuf (need %d, have %d)\n", len, bs->headbufavail);
// create a sub-buffer of the headbuf
retbuf = gst_buffer_create_sub (headbuf, GST_BUFFER_SIZE (headbuf) - bs->headbufavail, len);
// otherwise we need to figure out how to assemble one
}
else {
bs_print ("peek: current buffer is not big enough for len %d\n", len);
retbuf = gst_buffer_new ();
GST_BUFFER_SIZE (retbuf) = len;
GST_BUFFER_DATA (retbuf) = gst_bytestream_assemble (bs, len);
if (GST_BUFFER_OFFSET (headbuf) != -1)
GST_BUFFER_OFFSET (retbuf) = GST_BUFFER_OFFSET (headbuf) + (GST_BUFFER_SIZE (headbuf) - bs->headbufavail);
}
return retbuf;
}
guint8 *
gst_bytestream_peek_bytes (GstByteStream * bs, guint32 len)
{
GstBuffer *headbuf;
guint8 *data = NULL;
g_return_val_if_fail (bs != NULL, NULL);
g_return_val_if_fail (len > 0, NULL);
bs_print ("peek_bytes: asking for %d bytes\n", len);
// make sure we have enough
bs_print ("peek_bytes: there are %d bytes in the list\n", bs->listavail);
if (len > bs->listavail) {
gst_bytestream_fill_bytes (bs, len);
bs_print ("peek_bytes: there are now %d bytes in the list\n", bs->listavail);
}
gst_bytestream_print_status (bs);
// extract the head buffer
headbuf = GST_BUFFER (bs->buflist->data);
// if the requested bytes are in the current buffer
bs_print ("peek_bytes: headbufavail is %d\n", bs->headbufavail);
if (len <= bs->headbufavail) {
bs_print ("peek_bytes: there are enough bytes in headbuf (need %d, have %d)\n", len, bs->headbufavail);
// create a sub-buffer of the headbuf
data = GST_BUFFER_DATA (headbuf) + (GST_BUFFER_SIZE (headbuf) - bs->headbufavail);
// otherwise we need to figure out how to assemble one
}
else {
bs_print ("peek_bytes: current buffer is not big enough for len %d\n", len);
data = gst_bytestream_assemble (bs, len);
}
return data;
}
guint8 *
gst_bytestream_assemble (GstByteStream * bs, guint32 len)
{
guint8 *data = g_malloc (len);
GSList *walk;
guint32 copied = 0;
GstBuffer *buf; GstBuffer *buf;
g_print ("peek %08llx %08llx\n", len, bs->pos); // copy the data from the curbuf
buf = GST_BUFFER (bs->buflist->data);
bs_print ("assemble: copying %d bytes from curbuf at %d to *data\n", bs->headbufavail,
GST_BUFFER_SIZE (buf) - bs->headbufavail);
memcpy (data, GST_BUFFER_DATA (buf) + GST_BUFFER_SIZE (buf) - bs->headbufavail, bs->headbufavail);
copied += bs->headbufavail;
len = gst_bytestream_fill (bs, len); // asumption is made that the buffers all exist in the list
walk = g_slist_next (bs->buflist);
while (copied < len) {
buf = GST_BUFFER (walk->data);
if (GST_BUFFER_SIZE (buf) < (len - copied)) {
bs_print ("assemble: copying %d bytes from buf to output offset %d\n", GST_BUFFER_SIZE (buf), copied);
memcpy (data + copied, GST_BUFFER_DATA (buf), GST_BUFFER_SIZE (buf));
copied += GST_BUFFER_SIZE (buf);
}
else {
bs_print ("assemble: copying %d bytes from buf to output offset %d\n", len - copied, copied);
memcpy (data + copied, GST_BUFFER_DATA (buf), len - copied);
copied = len;
}
walk = g_slist_next (walk);
}
buf = gst_buffer_create_sub (bs->buffer, bs->index, len); return data;
return buf;
}
GstBuffer*
gst_bytestream_read (GstByteStream *bs, guint64 len)
{
GstBuffer *buf;
g_print ("read %08llx %08llx\n", len, bs->pos);
buf = gst_bytestream_peek (bs, len);
gst_bytestream_shrink (bs, GST_BUFFER_SIZE (buf));
return buf;
} }
gboolean gboolean
gst_bytestream_seek (GstByteStream *bs, guint64 offset) gst_bytestream_flush (GstByteStream * bs, guint32 len)
{ {
return FALSE; GstBuffer *headbuf;
bs_print ("flush: flushing %d bytes\n", len);
// make sure we have enough
bs_print ("flush: there are %d bytes in the list\n", bs->listavail);
if (len > bs->listavail) {
gst_bytestream_fill_bytes (bs, len);
bs_print ("flush: there are now %d bytes in the list\n", bs->listavail);
}
// repeat until we've flushed enough data
while (len > 0) {
headbuf = GST_BUFFER (bs->buflist->data);
bs_print ("flush: analyzing buffer that's %d bytes long, offset %d\n", GST_BUFFER_SIZE (headbuf),
GST_BUFFER_OFFSET (headbuf));
// if there's enough to complete the flush
if (bs->headbufavail > len) {
// just trim it off
bs_print ("flush: trimming %d bytes off end of headbuf\n", len);
bs->headbufavail -= len;
bs->listavail -= len;
len = 0;
// otherwise we have to trim the whole buffer
}
else {
bs_print ("flush: removing head buffer completely\n");
// remove it from the list
bs->buflist = g_slist_delete_link (bs->buflist, bs->buflist);
// trim it from the avail size
bs->listavail -= bs->headbufavail;
// record that we've trimmed this many bytes
len -= bs->headbufavail;
// unref it
gst_buffer_unref (headbuf);
// record the new headbufavail
if (bs->buflist) {
bs->headbufavail = GST_BUFFER_SIZE (GST_BUFFER (bs->buflist->data));
bs_print ("flush: next headbuf is %d bytes\n", bs->headbufavail);
}
else {
bs_print ("flush: no more bytes at all\n");
}
}
bs_print ("flush: bottom of while(), len is now %d\n", len);
}
return TRUE;
} }
gint64 GstBuffer *
gst_bytestream_flush (GstByteStream *bs, guint64 len) gst_bytestream_read (GstByteStream * bs, guint32 len)
{ {
guint64 outlen; GstBuffer *buf = gst_bytestream_peek (bs, len);
gst_bytestream_flush (bs, len);
g_print ("flush %08llx %08llx\n", len, bs->pos); return buf;
}
if (len == 0)
return len; void
gst_bytestream_print_status (GstByteStream * bs)
outlen = gst_bytestream_fill (bs, len); {
GSList *walk;
gst_bytestream_shrink (bs, outlen); GstBuffer *buf;
return outlen; bs_print ("STATUS: head buffer has %d bytes available\n", bs->headbufavail);
bs_print ("STATUS: list has %d bytes available\n", bs->listavail);
walk = bs->buflist;
while (walk) {
buf = GST_BUFFER (walk->data);
walk = g_slist_next (walk);
bs_print ("STATUS: buffer starts at %d and is %d bytes long\n", GST_BUFFER_OFFSET (buf), GST_BUFFER_SIZE (buf));
}
} }

47
libs/bytestream/gstbytestream.h
View file

@ -1,26 +1,3 @@
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstbytestream.h: Header for various utility functions
*
* 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.
*/
#ifndef __GST_BYTESTREAM_H__ #ifndef __GST_BYTESTREAM_H__
#define __GST_BYTESTREAM_H__ #define __GST_BYTESTREAM_H__
@ -32,26 +9,22 @@ extern "C" {
typedef struct _GstByteStream GstByteStream; typedef struct _GstByteStream GstByteStream;
struct _GstByteStream struct _GstByteStream {
{
GstPad *pad; GstPad *pad;
GstBuffer *buffer;
guint64 index; GSList *buflist;
guint64 pos; guint32 headbufavail;
guint64 size; guint32 listavail;
}; };
GstByteStream* gst_bytestream_new (GstPad *pad); GstByteStream* gst_bytestream_new (GstPad *pad);
void gst_bytestream_destroy (GstByteStream *bs); void gst_bytestream_destroy (GstByteStream *bs);
GstBuffer* gst_bytestream_peek (GstByteStream *bs, guint64 len); GstBuffer* gst_bytestream_read (GstByteStream *bs, guint32 len);
GstBuffer* gst_bytestream_read (GstByteStream *bs, guint64 len); GstBuffer* gst_bytestream_peek (GstByteStream *bs, guint32 len);
gboolean gst_bytestream_seek (GstByteStream *bs, guint64 offset); guint8* gst_bytestream_peek_bytes (GstByteStream *bs, guint32 len);
gint64 gst_bytestream_flush (GstByteStream *bs, guint64 len); gboolean gst_bytestream_flush (GstByteStream *bs, guint32 len);
void gst_bytestream_print_status (GstByteStream *bs);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* __GST_BYTESTREAM_H__ */ #endif /* __GST_BYTESTREAM_H__ */

327
libs/bytestream/gstbytestream2.c
View file

@ -1,327 +0,0 @@
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <gst/gstinfo.h>
#include "gstbytestream2.h"
//#define bs_print(format,args...) g_print(format, ## args)
#define bs_print(format,args...)
//static void gst_bytestream2_print_status(GstByteStream2 *bs);
guint8 *gst_bytestream2_assemble(GstByteStream2 *bs, guint32 len);
/**
* gst_bytestream_new:
* @pad: the pad to attach the bytestream to
*
* creates a bytestream from the given pad
*
* Returns: a new #GstByteStream object
*/
GstByteStream2*
gst_bytestream2_new (GstPad *pad)
{
GstByteStream2 *bs = g_new (GstByteStream2, 1);
bs->pad = pad;
bs->buflist = NULL;
bs->headbufavail = 0;
bs->listavail = 0;
return bs;
}
// HOW THIS WORKS:
//
// The fundamental structure is a singly-linked list of buffers. The
// buffer on the front is the oldest, and thus the first to read data
// from. The number of bytes left to be read in this buffer is stored
// in bs->headbufavail. The number of bytes available in the entire
// list (including the head buffer) is in bs->listavail.
//
// When a request is made for data (peek), _fill_bytes is called with
// the number of bytes needed, but only if the listavail indicates
// that there aren't already enough. This calls _get_next_buf until
// the listavail is sufficient to satisfy the demand.
//
// _get_next_buf pulls a buffer from the pad the bytestream is attached
// to, and shoves it in the list. There are actually two things it can
// do. If there's already a buffer in the list, and the _is_span_fast()
// test returns true, it will merge it with that last buffer. Otherwise
// it will simply tack it onto the end of the list.
//
// The _peek itself first checks the simple case of the request fitting
// within the head buffer, and if so creates a subbuffer and returns.
// Otherwise, it creates a new buffer and allocates space for the request
// and calls _assemble to fill it. We know we have to copy because this
// case only happens when the _merge wasn't feasible during _get_next_buf.
//
// The _flush method repeatedly inspects the head buffer and flushes as
// much data from it as it needs to, up to the size of the buffer. If
// the flush decimates the buffer, it's stripped, unref'd, and removed.
// get the next buffer
// if the buffer can be merged with the head buffer, do so
// else add it onto the head of the
static gboolean
gst_bytestream2_get_next_buf(GstByteStream2 *bs) {
GstBuffer *nextbuf, *lastbuf;
GSList *end;
bs_print("get_next_buf: pulling buffer\n");
nextbuf = gst_pad_pull(bs->pad);
bs_print("get_next_buf: got buffer of %d bytes\n",GST_BUFFER_SIZE(nextbuf));
// first see if there are any buffers in the list at all
if (bs->buflist) {
bs_print("gst_next_buf: there is at least one buffer in the list\n");
// now find the end of the list
end = g_slist_last(bs->buflist);
// get the buffer that's there
lastbuf = GST_BUFFER(end->data);
// see if we can marge cheaply
if (gst_buffer_is_span_fast(lastbuf,nextbuf)) {
bs_print("get_next_buf: merging new buffer with last buf on list\n");
// it is, let's merge them (this is really an append, but...)
end->data = gst_buffer_merge(lastbuf,nextbuf);
// add to the length of the list
bs->listavail += GST_BUFFER_SIZE(nextbuf);
// have to check to see if we merged with the head buffer
if (end == bs->buflist) {
bs->headbufavail += GST_BUFFER_SIZE(nextbuf);
}
// we can ditch the nextbuf then
gst_buffer_unref(nextbuf);
// if we can't, we just append this buffer
} else {
bs_print("get_next_buf: adding new buffer to the end of the list\n");
end = g_slist_append(end,nextbuf);
// also need to increment length of list and buffer count
bs->listavail += GST_BUFFER_SIZE(nextbuf);
}
// if there are no buffers in the list
} else {
bs_print("get_next_buf: buflist is empty, adding new buffer to list\n");
// put this on the end of the list
bs->buflist = g_slist_append(bs->buflist,nextbuf);
// and increment the number of bytes in the list
bs->listavail = GST_BUFFER_SIZE(nextbuf);
// set the head buffer avail to the size
bs->headbufavail = GST_BUFFER_SIZE(nextbuf);
}
return TRUE;
}
static gboolean
gst_bytestream2_fill_bytes(GstByteStream2 *bs, guint32 len) {
// as long as we don't have enough, we get more buffers
while (bs->listavail < len) {
bs_print("fill_bytes: there are %d bytes in the list, we need %d\n",bs->listavail,len);
gst_bytestream2_get_next_buf(bs);
}
return TRUE;
}
GstBuffer *
gst_bytestream2_peek (GstByteStream2 *bs, guint32 len) {
GstBuffer *headbuf, *retbuf = NULL;
g_return_val_if_fail(bs != NULL, NULL);
g_return_val_if_fail(len > 0, NULL);
bs_print("peek: asking for %d bytes\n",len);
// make sure we have enough
bs_print("peek: there are %d bytes in the list\n",bs->listavail);
if (len > bs->listavail) {
gst_bytestream2_fill_bytes(bs,len);
bs_print("peek: there are now %d bytes in the list\n",bs->listavail);
}
gst_bytestream2_print_status(bs);
// extract the head buffer
headbuf = GST_BUFFER(bs->buflist->data);
// if the requested bytes are in the current buffer
bs_print("peek: headbufavail is %d\n",bs->headbufavail);
if (len <= bs->headbufavail) {
bs_print("peek: there are enough bytes in headbuf (need %d, have %d)\n",len,bs->headbufavail);
// create a sub-buffer of the headbuf
retbuf = gst_buffer_create_sub(headbuf, GST_BUFFER_SIZE(headbuf) - bs->headbufavail, len);
// otherwise we need to figure out how to assemble one
} else {
bs_print("peek: current buffer is not big enough for len %d\n",len);
retbuf = gst_buffer_new();
GST_BUFFER_SIZE(retbuf) = len;
GST_BUFFER_DATA(retbuf) = gst_bytestream2_assemble(bs,len);
if (GST_BUFFER_OFFSET(headbuf) != -1)
GST_BUFFER_OFFSET(retbuf) = GST_BUFFER_OFFSET(headbuf) + (GST_BUFFER_SIZE(headbuf) - bs->headbufavail);
}
return retbuf;
}
guint8 *
gst_bytestream2_peek_bytes (GstByteStream2 *bs, guint32 len) {
GstBuffer *headbuf;
guint8 *data = NULL;
g_return_val_if_fail(bs != NULL, NULL);
g_return_val_if_fail(len > 0, NULL);
bs_print("peek_bytes: asking for %d bytes\n",len);
// make sure we have enough
bs_print("peek_bytes: there are %d bytes in the list\n",bs->listavail);
if (len > bs->listavail) {
gst_bytestream2_fill_bytes(bs,len);
bs_print("peek_bytes: there are now %d bytes in the list\n",bs->listavail);
}
gst_bytestream2_print_status(bs);
// extract the head buffer
headbuf = GST_BUFFER(bs->buflist->data);
// if the requested bytes are in the current buffer
bs_print("peek_bytes: headbufavail is %d\n",bs->headbufavail);
if (len <= bs->headbufavail) {
bs_print("peek_bytes: there are enough bytes in headbuf (need %d, have %d)\n",len,bs->headbufavail);
// create a sub-buffer of the headbuf
data = GST_BUFFER_DATA(headbuf) + (GST_BUFFER_SIZE(headbuf) - bs->headbufavail);
// otherwise we need to figure out how to assemble one
} else {
bs_print("peek_bytes: current buffer is not big enough for len %d\n",len);
data = gst_bytestream2_assemble(bs,len);
}
return data;
}
guint8 *
gst_bytestream2_assemble(GstByteStream2 *bs, guint32 len)
{
guint8 *data = g_malloc(len);
GSList *walk;
guint32 copied = 0;
GstBuffer *buf;
// copy the data from the curbuf
buf = GST_BUFFER(bs->buflist->data);
bs_print("assemble: copying %d bytes from curbuf at %d to *data\n",bs->headbufavail,
GST_BUFFER_SIZE(buf) - bs->headbufavail);
memcpy(data,GST_BUFFER_DATA(buf) + GST_BUFFER_SIZE(buf) - bs->headbufavail,
bs->headbufavail);
copied += bs->headbufavail;
// asumption is made that the buffers all exist in the list
walk = g_slist_next(bs->buflist);
while (copied < len) {
buf = GST_BUFFER(walk->data);
if (GST_BUFFER_SIZE(buf) < (len-copied)) {
bs_print("assemble: copying %d bytes from buf to output offset %d\n",GST_BUFFER_SIZE(buf),copied);
memcpy(data+copied,GST_BUFFER_DATA(buf),GST_BUFFER_SIZE(buf));
copied += GST_BUFFER_SIZE(buf);
} else {
bs_print("assemble: copying %d bytes from buf to output offset %d\n",len-copied,copied);
memcpy(data+copied,GST_BUFFER_DATA(buf),len-copied);
copied = len;
}
walk = g_slist_next(walk);
}
return data;
}
gboolean
gst_bytestream2_flush(GstByteStream2 *bs, guint32 len)
{
GstBuffer *headbuf;
bs_print("flush: flushing %d bytes\n",len);
// make sure we have enough
bs_print("flush: there are %d bytes in the list\n",bs->listavail);
if (len > bs->listavail) {
gst_bytestream2_fill_bytes(bs,len);
bs_print("flush: there are now %d bytes in the list\n",bs->listavail);
}
// repeat until we've flushed enough data
while (len > 0) {
headbuf = GST_BUFFER(bs->buflist->data);
bs_print("flush: analyzing buffer that's %d bytes long, offset %d\n",GST_BUFFER_SIZE(headbuf),GST_BUFFER_OFFSET(headbuf));
// if there's enough to complete the flush
if (bs->headbufavail > len) {
// just trim it off
bs_print("flush: trimming %d bytes off end of headbuf\n",len);
bs->headbufavail -= len;
bs->listavail -= len;
len = 0;
// otherwise we have to trim the whole buffer
} else {
bs_print("flush: removing head buffer completely\n");
// remove it from the list
bs->buflist = g_slist_delete_link(bs->buflist,bs->buflist);
// trim it from the avail size
bs->listavail -= bs->headbufavail;
// record that we've trimmed this many bytes
len -= bs->headbufavail;
// unref it
gst_buffer_unref(headbuf);
// record the new headbufavail
if (bs->buflist) {
bs->headbufavail = GST_BUFFER_SIZE(GST_BUFFER(bs->buflist->data));
bs_print("flush: next headbuf is %d bytes\n",bs->headbufavail);
} else {
bs_print("flush: no more bytes at all\n");
}
}
bs_print("flush: bottom of while(), len is now %d\n",len);
}
}
GstBuffer *
gst_bytestream2_read(GstByteStream2 *bs, guint32 len)
{
GstBuffer *buf = gst_bytestream2_peek(bs,len);
gst_bytestream2_flush(bs,len);
return buf;
}
void
gst_bytestream2_print_status(GstByteStream2 *bs) {
GSList *walk;
GstBuffer *buf;
bs_print("STATUS: head buffer has %d bytes available\n",bs->headbufavail);
bs_print("STATUS: list has %d bytes available\n",bs->listavail);
walk = bs->buflist;
while (walk) {
buf = GST_BUFFER(walk->data);
walk = g_slist_next(walk);
bs_print("STATUS: buffer starts at %d and is %d bytes long\n",GST_BUFFER_OFFSET(buf),GST_BUFFER_SIZE(buf));
}
}

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libs/bytestream/gstbytestream2.h
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@ -1,29 +0,0 @@
#ifndef __GST_BYTESTREAM2_H__
#define __GST_BYTESTREAM2_H__
#include <gst/gstpad.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
typedef struct _GstByteStream2 GstByteStream2;
struct _GstByteStream2 {
GstPad *pad;
GSList *buflist;
guint32 headbufavail;
guint32 listavail;
};
GstByteStream2 * gst_bytestream2_new (GstPad *pad);
GstBuffer * gst_bytestream2_read (GstByteStream2 *bs, guint32 len);
GstBuffer * gst_bytestream2_peek (GstByteStream2 *bs, guint32 len);
guint8 * gst_bytestream2_peek_bytes (GstByteStream2 *bs, guint32 len);
gboolean gst_bytestream2_flush (GstByteStream2 *bs, guint32 len);
void gst_bytestream2_print_status(GstByteStream2 *bs);
#endif /* __GST_BYTESTREAM2_H__ */