+/*
+ * Copyright (C) 2009-2014 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file buffer_tree.c Buffer tree and buffer pool implementations. */
#include <regex.h>
-#include <stdbool.h>
#include "para.h"
#include "list.h"
int refcount;
/* NULL means no buffer pool but a malloced buffer. */
struct btr_pool *pool;
+ /* Only relevant if pool is NULL. */
+ bool dont_free;
};
struct btr_buffer_reference {
* Create a new buffer pool.
*
* \param name The name of the new buffer pool.
- *
- * \param area The size in bytes of the pool area.
+ * \param area_size The size in bytes of the pool area.
*
* \return An opaque pointer to the newly created buffer pool. It must be
* passed to btr_pool_free() after it is no longer used to deallocate all
}
/**
- * Dellocate resources used by a buffer pool.
+ * Deallocate resources used by a buffer pool.
*
* \param btrp A pointer obtained via btr_pool_new().
*/
return btrp->area_end - btrp->area_start;
}
-size_t btr_pool_filled(struct btr_pool *btrp)
+static size_t btr_pool_filled(struct btr_pool *btrp)
{
if (!btrp->whead)
return btr_pool_size(btrp);
* Return maximal size available for one read. This is
* smaller than the value returned by btr_pool_unused().
*/
-size_t btr_pool_available(struct btr_pool *btrp)
+static size_t btr_pool_available(struct btr_pool *btrp)
{
if (!btrp->whead)
return 0;
return btr_pool_available(btrp);
}
+/**
+ * Get references to buffers pointing to free space of the buffer pool area.
+ *
+ * \param btrp The buffer pool.
+ * \param iov The scatter array.
+ *
+ * \return Zero if the buffer pool is full, one if the free space of the buffer
+ * pool area is available as a single contiguous buffer, two if the free space
+ * consists of two buffers. If this function returns the value n, then n
+ * elements of \a iov are initialized.
+ */
+int btr_pool_get_buffers(struct btr_pool *btrp, struct iovec iov[2])
+{
+ size_t sz, unused;
+ char *buf;
+
+ sz = btr_pool_get_buffer(btrp, &buf);
+ if (sz == 0)
+ return 0;
+ iov[0].iov_len = sz;
+ iov[0].iov_base = buf;
+ unused = btr_pool_unused(btrp);
+ if (sz == unused)
+ return 1;
+ iov[1].iov_len = unused - sz;
+ iov[1].iov_base = btrp->area_start;
+ return 2;
+}
+
/**
* Mark a part of the buffer pool area as allocated.
*
*
* \param bnd Specifies how to create the new node.
*
- * This function always succeeds (or calls exit()). The returned pointer
- * must be freed using btr_free_node() after it has been removed from
- * the buffer tree via btr_remove_node().
+ * \return A pointer to the newly allocated node.
+ *
+ * This function always succeeds (or calls exit()). The returned pointer must
+ * be freed using btr_free_node() after the node has been removed from the
+ * buffer tree via btr_remove_node().
*/
struct btr_node *btr_new_node(struct btr_node_description *bnd)
{
bnd->child->parent = btrn;
goto out;
}
- PARA_EMERG_LOG("inserting internal nodes not yet supported.\n");
- exit(EXIT_FAILURE);
- assert(bnd->child->parent == bnd->parent);
+ list_add_tail(&btrn->node, &bnd->parent->children);
+ list_move(&bnd->child->node, &btrn->children);
+ bnd->child->parent = btrn;
+ PARA_INFO_LOG("added %s as internal node\n", bnd->name);
out:
return btrn;
}
{
if (btrb->pool)
btr_pool_deallocate(btrb->pool, btrb->size);
- else
+ else if (!btrb->dont_free)
free(btrb->buf);
}
{
struct btr_buffer *btrb;
- assert(size != 0);
+ if (size == 0)
+ return;
if (list_empty(&btrn->children)) {
free(buf);
return;
add_btrb_to_children(btrb, btrn, 0);
}
+/**
+ * Insert a buffer into the buffer tree, non-freeing variant.
+ *
+ * \param buf See \ref btr_add_output().
+ * \param size See \ref btr_add_output().
+ * \param btrn See \ref btr_add_output().
+ *
+ * This is similar to btr_add_output() but additionally sets the \p dont_free
+ * flag on \a buf. If the refcount for the buffer drops to zero, \a buf will
+ * not be deallocated if this flag is set.
+ *
+ * The \p dont_free bit also prevents the children of \a btrn from modifying
+ * the buffer contents inplace. Specifically, \ref btr_inplace_ok() returns
+ * false if there is any buffer in the input queue with the \p dont_free bit
+ * set.
+ */
+void btr_add_output_dont_free(const char *buf, size_t size, struct btr_node *btrn)
+{
+ struct btr_buffer *btrb;
+
+ if (size == 0)
+ return;
+ if (list_empty(&btrn->children))
+ return;
+ btrb = new_btrb((char *)buf, size);
+ btrb->dont_free = true;
+ add_btrb_to_children(btrb, btrn, 0);
+}
+
/**
* Feed data to child nodes of a buffer tree node.
*
char *buf;
size_t avail;
- assert(size != 0);
+ if (size == 0)
+ return;
if (list_empty(&btrn->children))
return;
avail = btr_pool_get_buffer(btrp, &buf);
btr_drop_buffer_reference(br);
}
+/**
+ * Feed all buffer references of the input queue through the output channel.
+ *
+ * \param btrn The node whose buffer references should be pushed down.
+ *
+ * This function is useful for filters that do not change the contents of the
+ * buffers at all, like the wav filter or the amp filter if no amplification
+ * was specified. This function is rather cheap.
+ *
+ * \sa \ref btr_pushdown_one().
+ */
void btr_pushdown(struct btr_node *btrn)
{
struct btr_buffer_reference *br, *tmp;
btr_pushdown_br(br, btrn);
}
-int btr_pushdown_one(struct btr_node *btrn)
+/**
+ * Feed the next buffer of the input queue through the output channel.
+ *
+ * \param btrn The node whose first input queue buffer should be pushed down.
+ *
+ * This works like \ref btr_pushdown() but pushes down only one buffer
+ * reference.
+ */
+void btr_pushdown_one(struct btr_node *btrn)
{
struct btr_buffer_reference *br;
if (list_empty(&btrn->input_queue))
- return 0;
+ return;
br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
btr_pushdown_br(br, btrn);
- return 1;
}
/*
}
/**
- * Find out whether a node is an orphan node.
+ * Find out whether a node is an orphan.
*
* \param btrn The buffer tree node.
*
* \return True if \a btrn has no parent.
*
- * This function will always return true for the root node. However in case
- * nodes have been removed from the tree, other nodes may become orphans too.
+ * This function returns true for the root node and false for any other node.
+ *
+ * After a (non-leaf) node was removed removed from the tree, the function
+ * returns true for all child nodes.
*/
bool btr_no_parent(struct btr_node *btrn)
{
return !btrn->parent;
}
+/**
+ * Find out whether it is OK to change an input buffer.
+ *
+ * \param btrn The buffer tree node to check.
+ *
+ * This is used by filters that produce exactly the same amount of output as
+ * there is input. The amp filter which multiplies each sample by some number
+ * is an example of such a filter. If there are no other nodes in the buffer
+ * tree that read the same input stream (i.e. if \a btrn has no siblings), a
+ * node may modify its input buffer directly and push down the modified buffer
+ * to its children, thereby avoiding to allocate a possibly large additional
+ * buffer.
+ *
+ * Since the buffer tree may change at any time, this function should be called
+ * during each post_select call.
+ *
+ * \return True if \a btrn has no siblings.
+ */
bool btr_inplace_ok(struct btr_node *btrn)
{
- if (!btrn->parent)
- return true;
- return list_is_singular(&btrn->parent->children);
+ struct btr_buffer_reference *br;
+ FOR_EACH_BUFFER_REF(br, btrn) {
+ struct btr_buffer *btrb = br->btrb;
+ if (btrb->refcount > 1)
+ return false;
+ if (btrb->dont_free == true)
+ return false;
+ }
+ return true;
}
static inline size_t br_available_bytes(struct btr_buffer_reference *br)
return br->btrb->size - br->consumed;
}
-size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
+static size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
{
if (buf)
*buf = br->btrb->buf + br->consumed;
}
/**
- * Obtain the next buffer of the input queue of a buffer tree node.
+ * Obtain the next buffer of the input queue, omitting data.
*
* \param btrn The node whose input queue is to be queried.
- * \param bufp Result pointer.
+ * \param omit Number of bytes to be omitted.
+ * \param bufp Result pointer. It is OK to pass \p NULL here.
+ *
+ * If a buffer tree node needs more input data but can not consume the data it
+ * already has (because it might be needed again later) this function can be
+ * used instead of btr_next_buffer() to get a reference to the buffer obtained
+ * by skipping the given number of bytes. Skipped input bytes are not consumed.
+ *
+ * With a zero \a omit argument, this function is equivalent to \ref
+ * btr_next_buffer().
*
- * \return The number of bytes that can be read from buf. Zero if the input
- * buffer queue is empty. In this case the value of \a bufp is undefined.
+ * \return Number of bytes in \a bufp. If there are less than or equal to \a
+ * omit many bytes available in the input queue of the buffer tree node pointed
+ * to by \a btrn, the function returns zero and the value of \a bufp is
+ * undefined.
*/
-size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
+size_t btr_next_buffer_omit(struct btr_node *btrn, size_t omit, char **bufp)
{
struct btr_buffer_reference *br;
+ size_t wrap_count, sz, rv = 0;
char *buf, *result = NULL;
- size_t sz, rv = 0;
- FOR_EACH_BUFFER_REF(br, btrn) {
+ br = get_first_input_br(btrn);
+ if (!br)
+ return 0;
+ wrap_count = br->wrap_count;
+ if (wrap_count > 0) { /* we have a wrap buffer */
sz = btr_get_buffer_by_reference(br, &buf);
- if (!result) {
- result = buf;
- rv = sz;
- if (!br->btrb->pool)
- break;
- continue;
+ if (sz > omit) { /* and it's big enough */
+ result = buf + omit;
+ rv = sz - omit;
+ /*
+ * Wrap buffers are allocated by malloc(), so the next
+ * buffer ref will not align nicely, so we return the
+ * tail of the wrap buffer.
+ */
+ goto out;
}
- if (!br->btrb->pool)
- break;
- if (result + rv != buf)
- break;
- rv += sz;
+ /*
+ * The next wrap_count bytes exist twice, in the wrap buffer
+ * and as a buffer reference in the buffer tree pool.
+ */
+ omit += wrap_count;
+ }
+ /*
+ * For buffer tree pools, the buffers in the list align, i.e. the next
+ * buffer in the list starts directly at the end of its predecessor. In
+ * this case we merge adjacent buffers and return one larger buffer
+ * instead.
+ */
+ FOR_EACH_BUFFER_REF(br, btrn) {
+ sz = btr_get_buffer_by_reference(br, &buf);
+ if (result) {
+ if (result + rv != buf)
+ goto out;
+ rv += sz;
+ } else if (sz > omit) {
+ result = buf + omit;
+ rv = sz - omit;
+ } else
+ omit -= sz;
}
+ if (!result)
+ return 0;
+out:
if (bufp)
*bufp = result;
return rv;
}
+/**
+ * Obtain the next buffer of the input queue of a buffer tree node.
+ *
+ * \param btrn The node whose input queue is to be queried.
+ * \param bufp Result pointer.
+ *
+ * \return The number of bytes that can be read from buf.
+ *
+ * The call of this function is is equivalent to calling \ref
+ * btr_next_buffer_omit() with an \a omit value of zero.
+ */
+size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
+{
+ return btr_next_buffer_omit(btrn, 0, bufp);
+}
+
/**
* Deallocate the given number of bytes from the input queue.
*
*
* This function must be used to get rid of existing buffer references in the
* node's input queue. If no references to a buffer remain, the underlying
- * buffers are either freed (in the non-buffer tree case) or the read head of
+ * buffers are either freed (in the non-buffer pool case) or the read head of
* the buffer pool is being advanced.
*
* Note that \a numbytes may be smaller than the buffer size. In this case the
numbytes -= br->btrb->size - br->consumed;
btr_drop_buffer_reference(br);
}
- assert(true);
+ assert(false);
}
/*
* We have a wrap buffer, consume from it. If in total, i.e. including
return btr_consume(btrn, sz);
}
-static void flush_input_queue(struct btr_node *btrn)
+/**
+ * Clear the input queue of a buffer tree node.
+ *
+ * \param btrn The node whose input queue should be cleared.
+ */
+void btr_drain(struct btr_node *btrn)
{
struct btr_buffer_reference *br, *tmp;
+
FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
btr_drop_buffer_reference(br);
}
-void btr_free_node(struct btr_node *btrn)
+static void btr_free_node(struct btr_node *btrn)
{
- if (!btrn)
- return;
free(btrn->name);
free(btrn);
}
-void btr_remove_node(struct btr_node *btrn)
+/**
+ * Remove a node from a buffer tree.
+ *
+ * \param btrnp Determines the node to remove.
+ *
+ * This orphans all children of the node given by \a btrnp and removes this
+ * node from the child list of its parent. Moreover, the input queue is flushed
+ * and the node pointer given by \a btrp is set to \p NULL.
+ *
+ * \sa \ref btr_splice_out_node.
+ */
+void btr_remove_node(struct btr_node **btrnp)
{
struct btr_node *ch;
+ struct btr_node *btrn;
- if (!btrn)
+ if (!btrnp)
return;
- PARA_NOTICE_LOG("removing btr node %s from buffer tree\n", btrn->name);
+ btrn = *btrnp;
+ if (!btrn)
+ goto out;
+ PARA_INFO_LOG("removing btr node %s from buffer tree\n", btrn->name);
FOR_EACH_CHILD(ch, btrn)
ch->parent = NULL;
- flush_input_queue(btrn);
+ btr_drain(btrn);
if (btrn->parent)
list_del(&btrn->node);
+ btr_free_node(btrn);
+out:
+ *btrnp = NULL;
}
/**
return size;
}
-void btr_splice_out_node(struct btr_node *btrn)
+/**
+ * Remove a node from the buffer tree, reconnecting parent and children.
+ *
+ * \param btrnp The node to splice out.
+ *
+ * This function is used by buffer tree nodes that do not exist during the
+ * whole lifetime of the buffer tree. Unlike btr_remove_node(), calling
+ * btr_splice_out_node() does not split the tree into disconnected components
+ * but reconnects the buffer tree by making all child nodes of \a btrn children
+ * of the parent of \a btrn.
+ */
+void btr_splice_out_node(struct btr_node **btrnp)
{
- struct btr_node *ch, *tmp;
+ struct btr_node *btrn = *btrnp, *ch, *tmp;
assert(btrn);
PARA_NOTICE_LOG("splicing out %s\n", btrn->name);
ch->parent = btrn->parent;
if (btrn->parent)
list_move(&ch->node, &btrn->parent->children);
+ else
+ list_del(&ch->node);
}
assert(list_empty(&btrn->children));
+ btr_free_node(btrn);
+ *btrnp = NULL;
}
/**
- * Return the size of the largest input queue.
+ * Return number of queued output bytes of a buffer tree node.
*
- * Iterates over all children of the given node.
+ * \param btrn The node whose output queue size should be computed.
+ *
+ * \return This function iterates over all children of the given node and
+ * returns the size of the largest input queue.
*/
-static size_t btr_bytes_pending(struct btr_node *btrn)
+size_t btr_get_output_queue_size(struct btr_node *btrn)
{
size_t max_size = 0;
struct btr_node *ch;
return max_size;
}
-int btr_exec(struct btr_node *btrn, const char *command, char **value_result)
-{
- if (!btrn)
- return -ERRNO_TO_PARA_ERROR(EINVAL);
- if (!btrn->execute)
- return -ERRNO_TO_PARA_ERROR(ENOTSUP);
- return btrn->execute(btrn, command, value_result);
-}
-
/**
- * Execute a inter-node command.
+ * Execute an inter-node command on the given node or on a parent node.
+ *
+ * \param btrn The node to start looking.
+ * \param command The command to execute.
+ * \param value_result Additional arguments and result value.
+ *
+ * This function traverses the buffer tree from \a btrn upwards and looks for
+ * the first node that understands \a command. On this node \a command is
+ * executed, and the result is stored in \a value_result.
+ *
+ * \return \p -ENOTSUP if no parent node of \a btrn understands \a command.
+ * Otherwise the return value of the command handler is returned.
+ *
+ * \sa \ref receiver::execute, filter::execute, writer::execute.
*/
int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result)
{
int ret;
for (; btrn; btrn = btrn->parent) {
- struct btr_node *parent = btrn->parent;
- if (!parent)
- return -ERRNO_TO_PARA_ERROR(ENOTSUP);
- if (!parent->execute)
+ if (!btrn->execute)
continue;
- PARA_INFO_LOG("parent: %s, cmd: %s\n", parent->name, command);
- ret = parent->execute(parent, command, value_result);
+ PARA_INFO_LOG("executing %s on %s\n", command, btrn->name);
+ ret = btrn->execute(btrn, command, value_result);
if (ret == -ERRNO_TO_PARA_ERROR(ENOTSUP))
continue;
if (ret < 0)
return ret;
if (value_result && *value_result)
- PARA_NOTICE_LOG("%s(%s): %s\n", command, parent->name,
+ PARA_INFO_LOG("%s(%s): %s\n", command, btrn->name,
*value_result);
return 1;
}
return -ERRNO_TO_PARA_ERROR(ENOTSUP);
}
+/**
+ * Obtain the context of a buffer node tree.
+ *
+ * \param btrn The node whose output queue size should be computed.
+ *
+ * \return A pointer to the \a context address specified at node creation time.
+ *
+ * \sa btr_new_node(), struct \ref btr_node_description.
+ */
void *btr_context(struct btr_node *btrn)
{
return btrn->context;
struct btr_buffer_reference *br, *wbr = NULL;
int num_refs; /* including wrap buffer */
char *buf, *buf1 = NULL, *buf2 = NULL;
- size_t sz, sz1 = 0, sz2 = 0, wsz;
+ size_t sz, sz1 = 0, sz2 = 0, wb_consumed = 0;
br = get_first_input_br(btrn);
if (!br || br_available_bytes(br) >= dest_size)
wbr = br;
if (sz >= dest_size)
return;
+ wb_consumed = br->consumed;
continue;
}
if (!buf1) {
assert(buf2 + sz2 == buf);
sz2 += sz;
next:
- if (sz1 + sz2 >= dest_size)
+ if (sz1 + sz2 >= dest_size + wb_consumed)
break;
}
if (!buf2) /* nothing to do */
para_list_add(&br->node, &btrn->input_queue);
return;
}
- PARA_DEBUG_LOG("increasing wrap buffer, sz1: %zu, sz2: %zu\n", sz1, sz2);
/*
* We already have a wrap buffer, but it is too small. It might be
* partially used.
*/
- wsz = br_available_bytes(wbr);
if (wbr->wrap_count == sz1 && wbr->btrb->size >= sz1 + sz2) /* nothing we can do about it */
return;
sz = sz1 + sz2 - wbr->btrb->size; /* amount of new data */
+ PARA_DEBUG_LOG("increasing wrap buffer %zu -> %zu\n", wbr->btrb->size,
+ wbr->btrb->size + sz);
wbr->btrb->size += sz;
wbr->btrb->buf = para_realloc(wbr->btrb->buf, wbr->btrb->size);
/* copy the new data to the end of the reallocated buffer */
if (i == 2)
break;
}
+ assert(i == 2);
/* make a new btrb that combines the two buffers and a br to it. */
sz = szs[0] + szs[1];
buf = para_malloc(sz);
return 2;
}
+/**
+ * Combine input queue buffers.
+ *
+ * \param btrn The buffer tree node whose input should be merged.
+ * \param dest_size Stop merging if a buffer of at least this size exists.
+ *
+ * Used to combine as many buffers as needed into a single buffer whose size is
+ * at least \a dest_size. This function is rather cheap in case the parent node
+ * uses buffer pools and rather expensive otherwise.
+ *
+ * Note that if less than \a dest_size bytes are available in total, this
+ * function does nothing and subsequent calls to btr_next_buffer() will still
+ * return a buffer size less than \a dest_size.
+ */
void btr_merge(struct btr_node *btrn, size_t dest_size)
{
if (need_buffer_pool_merge(btrn))
}
}
-bool btr_eof(struct btr_node *btrn)
+static bool btr_eof(struct btr_node *btrn)
{
char *buf;
size_t len = btr_next_buffer(btrn, &buf);
return (len == 0 && btr_no_parent(btrn));
}
-void log_tree_recursively(struct btr_node *btrn, int loglevel, int depth)
+static void log_tree_recursively(struct btr_node *btrn, int loglevel, int depth)
{
struct btr_node *ch;
const char spaces[] = " ", *space = spaces + 16 - depth;
log_tree_recursively(ch, loglevel, depth + 1);
}
+/**
+ * Write the current buffer (sub-)tree to the log.
+ *
+ * \param btrn Start logging at this node.
+ * \param loglevel Set severity with which the tree should be logged.
+ */
void btr_log_tree(struct btr_node *btrn, int loglevel)
{
return log_tree_recursively(btrn, loglevel, 0);
}
-/*
- * \return \a root if \a name is \p NULL.
+/**
+ * Find the node with the given name in the buffer tree.
+ *
+ * \param name The name of the node to search.
+ * \param root Where to start the search.
+ *
+ * \return A pointer to the node with the given name on success. If \a name is
+ * \p NULL, the function returns \a root. If there is no node with the given
+ * name, \p NULL is returned.
*/
struct btr_node *btr_search_node(const char *name, struct btr_node *root)
{
}
/** 640K ought to be enough for everybody ;) */
-#define BTRN_MAX_PENDING (640 * 1024)
+#define BTRN_MAX_PENDING (96 * 1024)
+/**
+ * Return the current state of a buffer tree node.
+ *
+ * \param btrn The node whose state should be queried.
+ * \param min_iqs The minimal input queue size.
+ * \param type The supposed type of \a btrn.
+ *
+ * Most users of the buffer tree subsystem call this function from both
+ * their pre_select and the post_select methods.
+ *
+ * \return Negative if an error condition was detected, zero if there
+ * is nothing to do and positive otherwise.
+ *
+ * Examples:
+ *
+ * - If a non-root node has no parent and an empty input queue, the function
+ * returns \p -E_BTR_EOF. Similarly, if a non-leaf node has no children, \p
+ * -E_BTR_NO_CHILD is returned.
+ *
+ * - If less than \a min_iqs many bytes are available in the input queue and no
+ * EOF condition was detected, the function returns zero.
+ *
+ * - If there's plenty of data left in the input queue of the children of \a
+ * btrn, the function also returns zero in order to bound the memory usage of
+ * the buffer tree.
+ */
int btr_node_status(struct btr_node *btrn, size_t min_iqs,
enum btr_node_type type)
{
size_t iqs;
assert(btrn);
- if (type != BTR_NT_LEAF) {
- if (btr_no_children(btrn))
- return -E_BTR_NO_CHILD;
- if (btr_bytes_pending(btrn) > BTRN_MAX_PENDING)
- return 0;
- }
- if (type != BTR_NT_ROOT) {
- if (btr_eof(btrn))
- return -E_BTR_EOF;
- iqs = btr_get_input_queue_size(btrn);
- if (iqs == 0) /* we have a parent, because not eof */
- return 0;
- if (iqs < min_iqs && !btr_no_parent(btrn))
- return 0;
- }
+ if (type != BTR_NT_LEAF && btr_no_children(btrn))
+ return -E_BTR_NO_CHILD;
+ if (type != BTR_NT_ROOT && btr_eof(btrn))
+ return -E_BTR_EOF;
+
+ if (btr_get_output_queue_size(btrn) > BTRN_MAX_PENDING)
+ return 0;
+ if (type == BTR_NT_ROOT)
+ return 1;
+ iqs = btr_get_input_queue_size(btrn);
+ if (iqs == 0) /* we have a parent, because not eof */
+ return 0;
+ if (iqs < min_iqs && !btr_no_parent(btrn))
+ return 0;
return 1;
}
+/**
+ * Get the time of the first I/O for a buffer tree node.
+ *
+ * \param btrn The node whose I/O time should be obtained.
+ * \param tv Result pointer.
+ *
+ * Mainly useful for the time display of para_audiod.
+ */
void btr_get_node_start(struct btr_node *btrn, struct timeval *tv)
{
*tv = btrn->start;
}
+
+/**
+ * Get the parent node of a buffer tree node.
+ *
+ * \param btrn The node whose parent should be returned.
+ *
+ * \a btrn must not be \p NULL.
+ *
+ * \return The parent of \a btrn, or \p NULL if \a btrn is the
+ * root node of the buffer tree.
+ */
+struct btr_node *btr_parent(struct btr_node *btrn)
+{
+ return btrn->parent;
+}
projects / paraslash.git / blobdiff