7 #include "buffer_tree.h"
11 /* whead = NULL means area full */
23 /** The number of references to this buffer. */
25 /* NULL means no buffer pool but a malloced buffer. */
26 struct btr_pool
*pool
;
29 struct btr_buffer_reference
{
30 struct btr_buffer
*btrb
;
32 /* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
33 struct list_head node
;
39 struct btr_node
*parent
;
40 /* The position of this btr node in the buffer tree. */
41 struct list_head node
;
42 /* The children nodes of this btr node are linked together in a list. */
43 struct list_head children
;
44 /* Time of first data transfer. */
47 * The input queue is a list of references to btr buffers. Each item on
48 * the list represents an input buffer which has not been completely
49 * used by this btr node.
51 struct list_head input_queue
;
52 btr_command_handler execute
;
57 * Create a new buffer pool.
59 * \param name The name of the new buffer pool.
60 * \param area_size The size in bytes of the pool area.
62 * \return An opaque pointer to the newly created buffer pool. It must be
63 * passed to btr_pool_free() after it is no longer used to deallocate all
66 struct btr_pool
*btr_pool_new(const char *name
, size_t area_size
)
68 struct btr_pool
*btrp
;
70 PARA_INFO_LOG("%s, %zu bytes\n", name
, area_size
);
71 btrp
= para_malloc(sizeof(*btrp
));
72 btrp
->area_start
= para_malloc(area_size
);
73 btrp
->area_end
= btrp
->area_start
+ area_size
;
74 btrp
->rhead
= btrp
->area_start
;
75 btrp
->whead
= btrp
->area_start
;
76 btrp
->name
= para_strdup(name
);
81 * Deallocate resources used by a buffer pool.
83 * \param btrp A pointer obtained via btr_pool_new().
85 void btr_pool_free(struct btr_pool
*btrp
)
89 free(btrp
->area_start
);
95 * Return the size of the buffer pool area.
97 * \param btrp The buffer pool.
99 * \return The same value which was passed during creation time to
102 size_t btr_pool_size(struct btr_pool
*btrp
)
104 return btrp
->area_end
- btrp
->area_start
;
107 static size_t btr_pool_filled(struct btr_pool
*btrp
)
110 return btr_pool_size(btrp
);
111 if (btrp
->rhead
<= btrp
->whead
)
112 return btrp
->whead
- btrp
->rhead
;
113 return btr_pool_size(btrp
) - (btrp
->rhead
- btrp
->whead
);
117 * Get the number of unused bytes in the buffer pool.
119 * \param btrp The pool.
121 * \return The number of bytes that can currently be allocated.
123 * Note that in general the returned number of bytes is not available as a
124 * single contiguous buffer. Use btr_pool_available() to obtain the length of
125 * the largest contiguous buffer that can currently be allocated from the
128 size_t btr_pool_unused(struct btr_pool
*btrp
)
130 return btr_pool_size(btrp
) - btr_pool_filled(btrp
);
134 * Return maximal size available for one read. This is
135 * smaller than the value returned by btr_pool_unused().
137 static size_t btr_pool_available(struct btr_pool
*btrp
)
141 if (btrp
->rhead
<= btrp
->whead
)
142 return btrp
->area_end
- btrp
->whead
;
143 return btrp
->rhead
- btrp
->whead
;
147 * Obtain the current write head.
149 * \param btrp The buffer pool.
150 * \param result The write head is returned here.
152 * \return The maximal amount of bytes that may be written to the returned
155 size_t btr_pool_get_buffer(struct btr_pool
*btrp
, char **result
)
158 *result
= btrp
->whead
;
159 return btr_pool_available(btrp
);
163 * Get references to buffers pointing to free space of the buffer pool area.
165 * \param btrp The buffer pool.
166 * \param iov The scatter array.
168 * \return Zero if the buffer pool is full, one if the free space of the buffer
169 * pool area is available as a single contiguous buffer, two if the free space
170 * consists of two buffers. If this function returns the value n, then n
171 * elements of \a iov are initialized.
173 int btr_pool_get_buffers(struct btr_pool
*btrp
, struct iovec iov
[2])
178 sz
= btr_pool_get_buffer(btrp
, &buf
);
182 iov
[0].iov_base
= buf
;
183 unused
= btr_pool_unused(btrp
);
186 iov
[1].iov_len
= unused
- sz
;
187 iov
[1].iov_base
= btrp
->area_start
;
192 * Mark a part of the buffer pool area as allocated.
194 * \param btrp The buffer pool.
195 * \param size The amount of bytes to be allocated.
197 * This is usually called after the caller wrote to the buffer obtained by
198 * btr_pool_get_buffer().
200 static void btr_pool_allocate(struct btr_pool
*btrp
, size_t size
)
206 assert(size
<= btr_pool_available(btrp
));
207 end
= btrp
->whead
+ size
;
208 assert(end
<= btrp
->area_end
);
210 if (end
== btrp
->area_end
) {
211 PARA_DEBUG_LOG("%s: end of pool area reached\n", btrp
->name
);
212 end
= btrp
->area_start
;
214 if (end
== btrp
->rhead
) {
215 PARA_DEBUG_LOG("%s btrp buffer full\n", btrp
->name
);
216 end
= NULL
; /* buffer full */
221 static void btr_pool_deallocate(struct btr_pool
*btrp
, size_t size
)
223 char *end
= btrp
->rhead
+ size
;
227 assert(end
<= btrp
->area_end
);
228 assert(size
<= btr_pool_filled(btrp
));
229 if (end
== btrp
->area_end
)
230 end
= btrp
->area_start
;
232 btrp
->whead
= btrp
->rhead
;
234 if (btrp
->rhead
== btrp
->whead
)
235 btrp
->rhead
= btrp
->whead
= btrp
->area_start
;
238 #define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
239 &((_btrn)->children), node)
240 #define FOR_EACH_CHILD_SAFE(_tn, _tmp, _btrn) \
241 list_for_each_entry_safe((_tn), (_tmp), &((_btrn)->children), node)
243 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
244 list_for_each_entry((_br), &(_btrn)->input_queue, node)
245 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
246 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
249 * Create a new buffer tree node.
251 * \param bnd Specifies how to create the new node.
253 * This function always succeeds (or calls exit()). The returned pointer must
254 * be freed using btr_free_node() after the node has been removed from the
255 * buffer tree via btr_remove_node().
257 struct btr_node
*btr_new_node(struct btr_node_description
*bnd
)
259 struct btr_node
*btrn
= para_malloc(sizeof(*btrn
));
261 btrn
->name
= para_strdup(bnd
->name
);
262 btrn
->parent
= bnd
->parent
;
263 btrn
->execute
= bnd
->handler
;
264 btrn
->context
= bnd
->context
;
265 btrn
->start
.tv_sec
= 0;
266 btrn
->start
.tv_usec
= 0;
267 INIT_LIST_HEAD(&btrn
->children
);
268 INIT_LIST_HEAD(&btrn
->input_queue
);
271 list_add_tail(&btrn
->node
, &bnd
->parent
->children
);
272 PARA_INFO_LOG("new leaf node: %s (child of %s)\n",
273 bnd
->name
, bnd
->parent
->name
);
275 PARA_INFO_LOG("added %s as btr root\n", bnd
->name
);
279 assert(!bnd
->child
->parent
);
280 PARA_INFO_LOG("new root: %s (was %s)\n",
281 bnd
->name
, bnd
->child
->name
);
283 list_add_tail(&bnd
->child
->node
, &btrn
->children
);
285 bnd
->child
->parent
= btrn
;
288 PARA_EMERG_LOG("inserting internal nodes not yet supported.\n");
290 assert(bnd
->child
->parent
== bnd
->parent
);
296 * Allocate a new btr buffer.
298 * The freshly allocated buffer will have a zero refcount and will
299 * not be associated with a btr pool.
301 static struct btr_buffer
*new_btrb(char *buf
, size_t size
)
303 struct btr_buffer
*btrb
= para_calloc(sizeof(*btrb
));
310 static void dealloc_buffer(struct btr_buffer
*btrb
)
313 btr_pool_deallocate(btrb
->pool
, btrb
->size
);
318 static struct btr_buffer_reference
*get_first_input_br(struct btr_node
*btrn
)
320 if (list_empty(&btrn
->input_queue
))
322 return list_first_entry(&btrn
->input_queue
,
323 struct btr_buffer_reference
, node
);
327 * Deallocate the reference, release the resources if refcount drops to zero.
329 static void btr_drop_buffer_reference(struct btr_buffer_reference
*br
)
331 struct btr_buffer
*btrb
= br
->btrb
;
336 if (btrb
->refcount
== 0) {
337 dealloc_buffer(btrb
);
342 static void add_btrb_to_children(struct btr_buffer
*btrb
,
343 struct btr_node
*btrn
, size_t consumed
)
347 if (btrn
->start
.tv_sec
== 0)
349 FOR_EACH_CHILD(ch
, btrn
) {
350 struct btr_buffer_reference
*br
= para_calloc(sizeof(*br
));
352 br
->consumed
= consumed
;
353 list_add_tail(&br
->node
, &ch
->input_queue
);
355 if (ch
->start
.tv_sec
== 0)
361 * Insert a malloced buffer into the buffer tree.
363 * \param buf The buffer to insert.
364 * \param size The size of \a buf in bytes.
365 * \param btrn Position in the buffer tree to create the output.
367 * This creates references to \a buf and adds these references to each child of
368 * \a btrn. The buffer will be freed using standard free() once no buffer tree
369 * node is referencing it any more.
371 * Note that this function must not be used if \a buf was obtained from a
372 * buffer pool. Use btr_add_output_pool() in this case.
374 void btr_add_output(char *buf
, size_t size
, struct btr_node
*btrn
)
376 struct btr_buffer
*btrb
;
379 if (list_empty(&btrn
->children
)) {
383 btrb
= new_btrb(buf
, size
);
384 add_btrb_to_children(btrb
, btrn
, 0);
388 * Feed data to child nodes of a buffer tree node.
390 * \param btrp The buffer pool.
391 * \param size The number of bytes to be allocated and fed to each child.
392 * \param btrn The node whose children are to be fed.
394 * This function allocates the amount of bytes from the buffer pool area,
395 * starting at the current value of the write head, and creates buffer
396 * references to the resulting part of the buffer pool area, one for each child
397 * of \a btrn. The references are then fed into the input queue of each child.
399 void btr_add_output_pool(struct btr_pool
*btrp
, size_t size
,
400 struct btr_node
*btrn
)
402 struct btr_buffer
*btrb
;
407 if (list_empty(&btrn
->children
))
409 avail
= btr_pool_get_buffer(btrp
, &buf
);
410 assert(avail
>= size
);
411 btr_pool_allocate(btrp
, size
);
412 btrb
= new_btrb(buf
, size
);
414 add_btrb_to_children(btrb
, btrn
, 0);
418 * Copy data to write head of a buffer pool and feed it to all children nodes.
420 * \param src The source buffer.
421 * \param n The size of the source buffer in bytes.
422 * \param btrp The destination buffer pool.
423 * \param btrn Add the data as output of this node.
425 * This is expensive. The caller must make sure the data fits into the buffer
428 void btr_copy(const void *src
, size_t n
, struct btr_pool
*btrp
,
429 struct btr_node
*btrn
)
436 assert(n
<= btr_pool_unused(btrp
));
437 sz
= btr_pool_get_buffer(btrp
, &buf
);
438 copy
= PARA_MIN(sz
, n
);
439 memcpy(buf
, src
, copy
);
440 btr_add_output_pool(btrp
, copy
, btrn
);
443 sz
= btr_pool_get_buffer(btrp
, &buf
);
444 assert(sz
>= n
- copy
);
445 memcpy(buf
, src
+ copy
, n
- copy
);
446 btr_add_output_pool(btrp
, n
- copy
, btrn
);
449 static void btr_pushdown_br(struct btr_buffer_reference
*br
, struct btr_node
*btrn
)
451 add_btrb_to_children(br
->btrb
, btrn
, br
->consumed
);
452 btr_drop_buffer_reference(br
);
456 * Feed all buffer references of the input queue through the output channel.
458 * \param btrn The node whose buffer references should be pushed down.
460 * This function is useful for filters that do not change the contents of the
461 * buffers at all, like the wav filter or the amp filter if no amplification
462 * was specified. This function is rather cheap.
464 * \sa \ref btr_pushdown_one().
466 void btr_pushdown(struct btr_node
*btrn
)
468 struct btr_buffer_reference
*br
, *tmp
;
470 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
471 btr_pushdown_br(br
, btrn
);
475 * Feed the next buffer of the input queue through the output channel.
477 * \param btrn The node whose first input queue buffer should be pushed down.
479 * This works like \ref btr_pushdown() but pushes down only one buffer
482 void btr_pushdown_one(struct btr_node
*btrn
)
484 struct btr_buffer_reference
*br
;
486 if (list_empty(&btrn
->input_queue
))
488 br
= list_first_entry(&btrn
->input_queue
, struct btr_buffer_reference
, node
);
489 btr_pushdown_br(br
, btrn
);
493 * Find out whether a node is a leaf node.
495 * \param btrn The node to check.
497 * \return True if this node has no children. False otherwise.
499 static bool btr_no_children(struct btr_node
*btrn
)
501 return list_empty(&btrn
->children
);
505 * Find out whether a node is an orphan node.
507 * \param btrn The buffer tree node.
509 * \return True if \a btrn has no parent.
511 * This function will always return true for the root node. However in case
512 * nodes have been removed from the tree, other nodes may become orphans too.
514 bool btr_no_parent(struct btr_node
*btrn
)
516 return !btrn
->parent
;
520 * Find out whether it is OK to change an input buffer.
522 * \param btrn The buffer tree node to check.
524 * This is used by filters that produce exactly the same amount of output as
525 * there is input. The amp filter which multiplies each sample by some number
526 * is an example of such a filter. If there are no other nodes in the buffer
527 * tree that read the same input stream (i.e. if \a btrn has no siblings), a
528 * node may modify its input buffer directly and push down the modified buffer
529 * to its children, thereby avoiding to allocate a possibly large additional
532 * Since the buffer tree may change at any time, this function should be called
533 * during each post_select call.
535 * \return True if \a btrn has no siblings.
537 bool btr_inplace_ok(struct btr_node
*btrn
)
541 return list_is_singular(&btrn
->parent
->children
);
544 static inline size_t br_available_bytes(struct btr_buffer_reference
*br
)
546 return br
->btrb
->size
- br
->consumed
;
549 static size_t btr_get_buffer_by_reference(struct btr_buffer_reference
*br
, char **buf
)
552 *buf
= br
->btrb
->buf
+ br
->consumed
;
553 return br_available_bytes(br
);
557 * Obtain the next buffer of the input queue of a buffer tree node.
559 * \param btrn The node whose input queue is to be queried.
560 * \param bufp Result pointer.
562 * \return The number of bytes that can be read from buf. Zero if the input
563 * buffer queue is empty. In this case the value of \a bufp is undefined.
565 size_t btr_next_buffer(struct btr_node
*btrn
, char **bufp
)
567 struct btr_buffer_reference
*br
;
568 char *buf
, *result
= NULL
;
571 FOR_EACH_BUFFER_REF(br
, btrn
) {
572 sz
= btr_get_buffer_by_reference(br
, &buf
);
582 if (result
+ rv
!= buf
)
592 * Deallocate the given number of bytes from the input queue.
594 * \param btrn The buffer tree node.
595 * \param numbytes The number of bytes to be deallocated.
597 * This function must be used to get rid of existing buffer references in the
598 * node's input queue. If no references to a buffer remain, the underlying
599 * buffers are either freed (in the non-buffer tree case) or the read head of
600 * the buffer pool is being advanced.
602 * Note that \a numbytes may be smaller than the buffer size. In this case the
603 * buffer is not deallocated and subsequent calls to btr_next_buffer() return
604 * the remaining part of the buffer.
606 void btr_consume(struct btr_node
*btrn
, size_t numbytes
)
608 struct btr_buffer_reference
*br
, *tmp
;
613 br
= get_first_input_br(btrn
);
616 if (br
->wrap_count
== 0) {
618 * No wrap buffer. Drop buffer references whose buffer
619 * has been fully used. */
620 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
) {
621 if (br
->consumed
+ numbytes
<= br
->btrb
->size
) {
622 br
->consumed
+= numbytes
;
623 if (br
->consumed
== br
->btrb
->size
)
624 btr_drop_buffer_reference(br
);
627 numbytes
-= br
->btrb
->size
- br
->consumed
;
628 btr_drop_buffer_reference(br
);
633 * We have a wrap buffer, consume from it. If in total, i.e. including
634 * previous calls to brt_consume(), less than wrap_count has been
635 * consumed, there's nothing more we can do.
637 * Otherwise we drop the wrap buffer and consume from subsequent
638 * buffers of the input queue the correct amount of bytes. This is the
639 * total number of bytes that have been consumed from the wrap buffer.
641 PARA_DEBUG_LOG("consuming %zu/%zu bytes from wrap buffer\n", numbytes
,
642 br_available_bytes(br
));
644 assert(numbytes
<= br_available_bytes(br
));
645 if (br
->consumed
+ numbytes
< br
->wrap_count
) {
646 br
->consumed
+= numbytes
;
649 PARA_DEBUG_LOG("dropping wrap buffer (%zu bytes)\n", br
->btrb
->size
);
650 /* get rid of the wrap buffer */
651 sz
= br
->consumed
+ numbytes
;
652 btr_drop_buffer_reference(br
);
653 return btr_consume(btrn
, sz
);
656 static void flush_input_queue(struct btr_node
*btrn
)
658 struct btr_buffer_reference
*br
, *tmp
;
659 FOR_EACH_BUFFER_REF_SAFE(br
, tmp
, btrn
)
660 btr_drop_buffer_reference(br
);
664 * Free all resources allocated by btr_new_node().
666 * Like free(3), it is OK to call this with a \p NULL pointer argument.
668 void btr_free_node(struct btr_node
*btrn
)
677 * Remove a node from a buffer tree.
679 * \param btrn The node to remove.
681 * This makes all child nodes of \a btrn orphans and removes \a btrn from the
682 * list of children of its parent. Moreover, the input queue of \a btrn is
683 * flushed if it is not empty.
685 * \sa \ref btr_splice_out_node.
687 void btr_remove_node(struct btr_node
*btrn
)
693 PARA_NOTICE_LOG("removing btr node %s from buffer tree\n", btrn
->name
);
694 FOR_EACH_CHILD(ch
, btrn
)
696 flush_input_queue(btrn
);
698 list_del(&btrn
->node
);
702 * Return the amount of available input bytes of a buffer tree node.
704 * \param btrn The node whose input size should be computed.
706 * \return The total number of bytes available in the node's input
709 * This simply iterates over all buffer references in the input queue and
710 * returns the sum of the sizes of all references.
712 size_t btr_get_input_queue_size(struct btr_node
*btrn
)
714 struct btr_buffer_reference
*br
;
715 size_t size
= 0, wrap_consumed
= 0;
717 FOR_EACH_BUFFER_REF(br
, btrn
) {
718 if (br
->wrap_count
!= 0) {
719 wrap_consumed
= br
->consumed
;
722 size
+= br_available_bytes(br
);
724 assert(wrap_consumed
<= size
);
725 size
-= wrap_consumed
;
730 * Remove a node from the buffer tree, reconnecting parent and children.
732 * \param btrn The node to splice out.
734 * This function is used by buffer tree nodes that do not exist during the
735 * whole lifetime of the buffer tree. Unlike btr_remove_node(), calling
736 * btr_splice_out_node() does not split the tree into disconnected components
737 * but reconnects the buffer tree by making all child nodes of \a btrn children
738 * of the parent of \a btrn.
740 void btr_splice_out_node(struct btr_node
*btrn
)
742 struct btr_node
*ch
, *tmp
;
745 PARA_NOTICE_LOG("splicing out %s\n", btrn
->name
);
748 list_del(&btrn
->node
);
749 FOR_EACH_CHILD_SAFE(ch
, tmp
, btrn
) {
750 PARA_INFO_LOG("parent(%s): %s\n", ch
->name
,
751 btrn
->parent
? btrn
->parent
->name
: "NULL");
752 ch
->parent
= btrn
->parent
;
754 list_move(&ch
->node
, &btrn
->parent
->children
);
756 assert(list_empty(&btrn
->children
));
760 * Return the size of the largest input queue.
762 * Iterates over all children of the given node.
764 static size_t btr_bytes_pending(struct btr_node
*btrn
)
769 FOR_EACH_CHILD(ch
, btrn
) {
770 size_t size
= btr_get_input_queue_size(ch
);
771 max_size
= PARA_MAX(max_size
, size
);
776 int btr_exec(struct btr_node
*btrn
, const char *command
, char **value_result
)
779 return -ERRNO_TO_PARA_ERROR(EINVAL
);
781 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
782 return btrn
->execute(btrn
, command
, value_result
);
786 * Execute a inter-node command on a parent node.
788 * \param btrn The node to start looking.
789 * \param command The command to execute.
790 * \param value_result Additional arguments and result value.
792 * This function traverses the buffer tree upwards and looks for parent nodes
793 * of \a btrn that understands \a command. On the first such node the command
794 * is executed, and the result is stored in \a value_result.
796 * \return \p -ENOTSUP if no parent node of \a btrn understands \a command.
797 * Otherwise the return value of the command handler is returned.
799 int btr_exec_up(struct btr_node
*btrn
, const char *command
, char **value_result
)
803 for (; btrn
; btrn
= btrn
->parent
) {
804 struct btr_node
*parent
= btrn
->parent
;
806 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
807 if (!parent
->execute
)
809 PARA_INFO_LOG("parent: %s, cmd: %s\n", parent
->name
, command
);
810 ret
= parent
->execute(parent
, command
, value_result
);
811 if (ret
== -ERRNO_TO_PARA_ERROR(ENOTSUP
))
815 if (value_result
&& *value_result
)
816 PARA_NOTICE_LOG("%s(%s): %s\n", command
, parent
->name
,
820 return -ERRNO_TO_PARA_ERROR(ENOTSUP
);
824 * Obtain the context of a buffer node tree.
826 * The returned pointer equals the context pointer used at creation time of the
829 * \sa btr_new_node(), struct \ref btr_node_description.
831 void *btr_context(struct btr_node
*btrn
)
833 return btrn
->context
;
836 static bool need_buffer_pool_merge(struct btr_node
*btrn
)
838 struct btr_buffer_reference
*br
= get_first_input_br(btrn
);
842 if (br
->wrap_count
!= 0)
849 static void merge_input_pool(struct btr_node
*btrn
, size_t dest_size
)
851 struct btr_buffer_reference
*br
, *wbr
= NULL
;
852 int num_refs
; /* including wrap buffer */
853 char *buf
, *buf1
= NULL
, *buf2
= NULL
;
854 size_t sz
, sz1
= 0, sz2
= 0, wsz
;
856 br
= get_first_input_br(btrn
);
857 if (!br
|| br_available_bytes(br
) >= dest_size
)
860 FOR_EACH_BUFFER_REF(br
, btrn
) {
862 sz
= btr_get_buffer_by_reference(br
, &buf
);
865 if (br
->wrap_count
!= 0) {
867 assert(num_refs
== 1);
878 if (buf1
+ sz1
== buf
) {
887 assert(buf2
+ sz2
== buf
);
890 if (sz1
+ sz2
>= dest_size
)
893 if (!buf2
) /* nothing to do */
895 assert(buf1
&& sz2
> 0);
897 * If the second buffer is large, we only take the first part of it to
898 * avoid having to memcpy() huge buffers.
900 sz2
= PARA_MIN(sz2
, (size_t)(64 * 1024));
902 /* Make a new wrap buffer combining buf1 and buf2. */
904 buf
= para_malloc(sz
);
905 PARA_DEBUG_LOG("merging input buffers: (%p:%zu, %p:%zu) -> %p:%zu\n",
906 buf1
, sz1
, buf2
, sz2
, buf
, sz
);
907 memcpy(buf
, buf1
, sz1
);
908 memcpy(buf
+ sz1
, buf2
, sz2
);
909 br
= para_calloc(sizeof(*br
));
910 br
->btrb
= new_btrb(buf
, sz
);
911 br
->btrb
->refcount
= 1;
913 /* This is a wrap buffer */
914 br
->wrap_count
= sz1
;
915 para_list_add(&br
->node
, &btrn
->input_queue
);
919 * We already have a wrap buffer, but it is too small. It might be
922 wsz
= br_available_bytes(wbr
);
923 if (wbr
->wrap_count
== sz1
&& wbr
->btrb
->size
>= sz1
+ sz2
) /* nothing we can do about it */
925 sz
= sz1
+ sz2
- wbr
->btrb
->size
; /* amount of new data */
926 PARA_DEBUG_LOG("increasing wrap buffer %zu -> %zu\n", wbr
->btrb
->size
,
927 wbr
->btrb
->size
+ sz
);
928 wbr
->btrb
->size
+= sz
;
929 wbr
->btrb
->buf
= para_realloc(wbr
->btrb
->buf
, wbr
->btrb
->size
);
930 /* copy the new data to the end of the reallocated buffer */
932 memcpy(wbr
->btrb
->buf
+ wbr
->btrb
->size
- sz
, buf2
+ sz2
- sz
, sz
);
936 * Merge the first two input buffers into one.
938 * This is a quite expensive operation.
940 * \return The number of buffers that have been available (zero, one or two).
942 static int merge_input(struct btr_node
*btrn
)
944 struct btr_buffer_reference
*brs
[2], *br
;
949 if (list_empty(&btrn
->input_queue
))
951 if (list_is_singular(&btrn
->input_queue
))
954 /* get references to the first two buffers */
955 FOR_EACH_BUFFER_REF(br
, btrn
) {
957 szs
[i
] = btr_get_buffer_by_reference(brs
[i
], bufs
+ i
);
963 /* make a new btrb that combines the two buffers and a br to it. */
964 sz
= szs
[0] + szs
[1];
965 buf
= para_malloc(sz
);
966 PARA_DEBUG_LOG("%s: memory merging input buffers: (%zu, %zu) -> %zu\n",
967 btrn
->name
, szs
[0], szs
[1], sz
);
968 memcpy(buf
, bufs
[0], szs
[0]);
969 memcpy(buf
+ szs
[0], bufs
[1], szs
[1]);
971 br
= para_calloc(sizeof(*br
));
972 br
->btrb
= new_btrb(buf
, sz
);
973 br
->btrb
->refcount
= 1;
975 /* replace the first two refs by the new one */
976 btr_drop_buffer_reference(brs
[0]);
977 btr_drop_buffer_reference(brs
[1]);
978 para_list_add(&br
->node
, &btrn
->input_queue
);
983 * Combine input queue buffers.
985 * \param btrn The buffer tree node whose input should be merged.
986 * \param dest_size Stop merging if a buffer of at least this size exists.
988 * Used to combine as many buffers as needed into a single buffer whose size is
989 * at least \a dest_size. This function is rather cheap in case the parent node
990 * uses buffer pools and rather expensive otherwise.
992 * Note that if less than \a dest_size bytes are available in total, this
993 * function does nothing and subsequent calls to btr_next_buffer() will still
994 * return a buffer size less than \a dest_size.
996 void btr_merge(struct btr_node
*btrn
, size_t dest_size
)
998 if (need_buffer_pool_merge(btrn
))
999 return merge_input_pool(btrn
, dest_size
);
1002 size_t len
= btr_next_buffer(btrn
, &buf
);
1003 if (len
>= dest_size
)
1005 PARA_DEBUG_LOG("input size = %zu < %zu = dest\n", len
, dest_size
);
1006 if (merge_input(btrn
) < 2)
1011 static bool btr_eof(struct btr_node
*btrn
)
1014 size_t len
= btr_next_buffer(btrn
, &buf
);
1016 return (len
== 0 && btr_no_parent(btrn
));
1019 static void log_tree_recursively(struct btr_node
*btrn
, int loglevel
, int depth
)
1021 struct btr_node
*ch
;
1022 const char spaces
[] = " ", *space
= spaces
+ 16 - depth
;
1026 para_log(loglevel
, "%s%s\n", space
, btrn
->name
);
1027 FOR_EACH_CHILD(ch
, btrn
)
1028 log_tree_recursively(ch
, loglevel
, depth
+ 1);
1032 * Write the current buffer (sub-)tree to the log.
1034 * \param btrn Start logging at this node.
1035 * \param loglevel Set severity with which the tree should be logged.
1037 void btr_log_tree(struct btr_node
*btrn
, int loglevel
)
1039 return log_tree_recursively(btrn
, loglevel
, 0);
1043 * Find the node with the given name in the buffer tree.
1045 * \param name The name of the node to search.
1046 * \param root Where to start the search.
1048 * \return A pointer to the node with the given name on success. If \a name is
1049 * \p NULL, the function returns \a root. If there is no node with the given
1050 * name, \p NULL is returned.
1052 struct btr_node
*btr_search_node(const char *name
, struct btr_node
*root
)
1054 struct btr_node
*ch
;
1058 if (!strcmp(root
->name
, name
))
1060 FOR_EACH_CHILD(ch
, root
) {
1061 struct btr_node
*result
= btr_search_node(name
, ch
);
1068 /** 640K ought to be enough for everybody ;) */
1069 #define BTRN_MAX_PENDING (640 * 1024)
1072 * Return the current state of a buffer tree node.
1074 * \param btrn The node whose state should be queried.
1075 * \param min_iqs The minimal input queue size.
1076 * \param type The supposed type of \a btrn.
1078 * Most users of the buffer tree subsystem call this function from both
1079 * their pre_select and the post_select methods.
1081 * \return Negative if an error condition was detected, zero if there
1082 * is nothing to do and positive otherwise.
1086 * - If a non-root node has no parent and an empty input queue, the function
1087 * returns \p -E_BTR_EOF. Similarly, if a non-leaf node has no children, \p
1088 * -E_BTR_NO_CHILD is returned.
1090 * - If less than \a min_iqs many bytes are available in the input queue and no
1091 * EOF condition was detected, the function returns zero.
1093 * - If there's plenty of data left in the input queue of the children of \a
1094 * btrn, the function also returns zero in order to bound the memory usage of
1097 int btr_node_status(struct btr_node
*btrn
, size_t min_iqs
,
1098 enum btr_node_type type
)
1103 if (type
!= BTR_NT_LEAF
) {
1104 if (btr_no_children(btrn
))
1105 return -E_BTR_NO_CHILD
;
1106 if (btr_bytes_pending(btrn
) > BTRN_MAX_PENDING
)
1109 if (type
!= BTR_NT_ROOT
) {
1112 iqs
= btr_get_input_queue_size(btrn
);
1113 if (iqs
== 0) /* we have a parent, because not eof */
1115 if (iqs
< min_iqs
&& !btr_no_parent(btrn
))
1122 * Get the time of the first I/O for a buffer tree node.
1124 * \param btrn The node whose I/O time should be obtained.
1125 * \param tv Result pointer.
1127 * Mainly useful for the time display of para_audiod.
1129 void btr_get_node_start(struct btr_node
*btrn
, struct timeval
*tv
)