/**
* @file
*
* @ingroup ScoreChain
*
* @brief Chain Handler API.
*/
/*
* Copyright (c) 2010 embedded brains GmbH.
*
* COPYRIGHT (c) 1989-2006.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#ifndef _RTEMS_SCORE_CHAIN_H
# error "Never use <rtems/score/chain.inl> directly; include <rtems/score/chain.h> instead."
#endif
#ifndef _RTEMS_SCORE_CHAIN_INL
#define _RTEMS_SCORE_CHAIN_INL
/**
* @addtogroup ScoreChain
* @{
*/
/** @brief Set off chain
*
* This function sets the next and previous fields of the @a node to NULL
* indicating the @a node is not part of a chain.
*
* @param[in] node the node set to off chain.
*/
RTEMS_INLINE_ROUTINE void _Chain_Set_off_chain(
Chain_Node *node
)
{
node->next = node->previous = NULL;
}
/** @brief Is the Node off Chain
*
* This function returns true if the @a node is not on a chain. A @a node is
* off chain if the next and previous fields are set to NULL.
*
* @param[in] node is the node off chain.
*
* @return This function returns true if the @a node is off chain.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_node_off_chain(
const Chain_Node *node
)
{
return (node->next == NULL) && (node->previous == NULL);
}
/** @brief Are Two Nodes Equal
*
* This function returns true if @a left and @a right are equal,
* and false otherwise.
*
* @param[in] left is the node on the left hand side of the comparison.
* @param[in] right is the node on the left hand side of the comparison.
*
* @return This function returns true if @a left and @a right are equal,
* and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Are_nodes_equal(
const Chain_Node *left,
const Chain_Node *right
)
{
return left == right;
}
/** @brief Is this Chain Control Pointer Null
*
* This function returns true if the_chain is NULL and false otherwise.
*
* @param[in] the_chain is the chain to be checked for empty status.
*
* @return This method returns true if the_chain is NULL and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_null(
const Chain_Control *the_chain
)
{
return (the_chain == NULL);
}
/** @brief Is the Chain Node Pointer NULL
*
* This function returns true if the_node is NULL and false otherwise.
*
* @param[in] the_node is the node pointer to check.
*
* @return This method returns true if the_node is NULL and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_null_node(
const Chain_Node *the_node
)
{
return (the_node == NULL);
}
/** @brief Return pointer to Chain Head
*
* This function returns a pointer to the head node on the chain.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the permanent head node of the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Head(
Chain_Control *the_chain
)
{
return &the_chain->Head.Node;
}
/** @brief Return pointer to immutable Chain Head
*
* This function returns a pointer to the head node on the chain.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the permanent head node of the chain.
*/
RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_head(
const Chain_Control *the_chain
)
{
return &the_chain->Head.Node;
}
/** @brief Return pointer to Chain Tail
*
* This function returns a pointer to the last node on the chain.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the permanent tail node of the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Tail(
Chain_Control *the_chain
)
{
return &the_chain->Tail.Node;
}
/** @brief Return pointer to immutable Chain Tail
*
* This function returns a pointer to the last node on the chain.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the permanent tail node of the chain.
*/
RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_tail(
const Chain_Control *the_chain
)
{
return &the_chain->Tail.Node;
}
/** @brief Return pointer to Chain's First node
*
* This function returns a pointer to the first node on the chain after the
* head.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the first node of the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_First(
Chain_Control *the_chain
)
{
return _Chain_Head( the_chain )->next;
}
/** @brief Return pointer to immutable Chain's First node
*
* This function returns a pointer to the first node on the chain after the
* head.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the first node of the chain.
*/
RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_first(
const Chain_Control *the_chain
)
{
return _Chain_Immutable_head( the_chain )->next;
}
/** @brief Return pointer to Chain's Last node
*
* This function returns a pointer to the last node on the chain just before
* the tail.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the last node of the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Last(
Chain_Control *the_chain
)
{
return _Chain_Tail( the_chain )->previous;
}
/** @brief Return pointer to immutable Chain's Last node
*
* This function returns a pointer to the last node on the chain just before
* the tail.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This method returns the last node of the chain.
*/
RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_last(
const Chain_Control *the_chain
)
{
return _Chain_Immutable_tail( the_chain )->previous;
}
/** @brief Return pointer the next node from this node
*
* This function returns a pointer to the next node after this node.
*
* @param[in] the_node is the node to be operated upon.
*
* @return This method returns the next node on the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Next(
Chain_Node *the_node
)
{
return the_node->next;
}
/** @brief Return pointer the previous node from this node
*
* This function returns a pointer to the previous node on this chain.
*
* @param[in] the_node is the node to be operated upon.
*
* @return This method returns the previous node on the chain.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Previous(
Chain_Node *the_node
)
{
return the_node->previous;
}
/** @brief Is the Chain Empty
*
* This function returns true if there a no nodes on @a the_chain and
* false otherwise.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This function returns true if there a no nodes on @a the_chain and
* false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_empty(
const Chain_Control *the_chain
)
{
return _Chain_Immutable_first( the_chain )
== _Chain_Immutable_tail( the_chain );
}
/** @brief Is this the First Node on the Chain
*
* This function returns true if the_node is the first node on a chain and
* false otherwise.
*
* @param[in] the_node is the node the caller wants to know if it is
* the first node on a chain.
*
* @return This function returns true if @a the_node is the first node on
* a chain and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_first(
const Chain_Node *the_node
)
{
return (the_node->previous->previous == NULL);
}
/** @brief Is this the Last Node on the Chain
*
* This function returns true if @a the_node is the last node on a chain and
* false otherwise.
*
* @param[in] the_node is the node to check as the last node.
*
* @return This function returns true if @a the_node is the last node on
* a chain and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_last(
const Chain_Node *the_node
)
{
return (the_node->next->next == NULL);
}
/** @brief Does this Chain have only One Node
*
* This function returns true if there is only one node on @a the_chain and
* false otherwise.
*
* @param[in] the_chain is the chain to be operated upon.
*
* @return This function returns true if there is only one node on
* @a the_chain and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Has_only_one_node(
const Chain_Control *the_chain
)
{
return _Chain_Immutable_first( the_chain )
== _Chain_Immutable_last( the_chain );
}
/** @brief Is this Node the Chain Head
*
* This function returns true if @a the_node is the head of the_chain and
* false otherwise.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to check for being the Chain Head.
*
* @return This function returns true if @a the_node is the head of
* @a the_chain and false otherwise.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_head(
Chain_Control *the_chain,
const Chain_Node *the_node
)
{
return (the_node == _Chain_Head(the_chain));
}
/** @brief Is this Node the Chail Tail
*
* This function returns true if the_node is the tail of the_chain and
* false otherwise.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to check for being the Chain Tail.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Is_tail(
Chain_Control *the_chain,
const Chain_Node *the_node
)
{
return (the_node == _Chain_Tail(the_chain));
}
/** @brief Initialize this Chain as Empty
*
* This routine initializes the specified chain to contain zero nodes.
*
* @param[in] the_chain is the chain to be initialized.
*/
RTEMS_INLINE_ROUTINE void _Chain_Initialize_empty(
Chain_Control *the_chain
)
{
Chain_Node *head = _Chain_Head( the_chain );
Chain_Node *tail = _Chain_Tail( the_chain );
head->next = tail;
head->previous = NULL;
tail->previous = head;
}
/** @brief Extract this Node (unprotected)
*
* This routine extracts the_node from the chain on which it resides.
* It does NOT disable interrupts to ensure the atomicity of the
* extract operation.
*
* @param[in] the_node is the node to be extracted.
*/
RTEMS_INLINE_ROUTINE void _Chain_Extract_unprotected(
Chain_Node *the_node
)
{
Chain_Node *next;
Chain_Node *previous;
next = the_node->next;
previous = the_node->previous;
next->previous = previous;
previous->next = next;
}
/** @brief Get the First Node (unprotected)
*
* This function removes the first node from the_chain and returns
* a pointer to that node. It does NOT disable interrupts to ensure
* the atomicity of the get operation.
*
* @param[in] the_chain is the chain to attempt to get the first node from.
*
* @return This method returns the first node on the chain even if it is
* the Chain Tail.
*
* @note This routine assumes that there is at least one node on the chain
* and always returns a node even if it is the Chain Tail.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_first_unprotected(
Chain_Control *the_chain
)
{
Chain_Node *head = _Chain_Head( the_chain );
Chain_Node *old_first = head->next;
Chain_Node *new_first = old_first->next;
head->next = new_first;
new_first->previous = head;
return old_first;
}
/** @brief Get the First Node (unprotected)
*
* This function removes the first node from the_chain and returns
* a pointer to that node. If the_chain is empty, then NULL is returned.
*
* @param[in] the_chain is the chain to attempt to get the first node from.
*
* @return This method returns the first node on the chain or NULL if the
* chain is empty.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* get operation.
*/
RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_unprotected(
Chain_Control *the_chain
)
{
if ( !_Chain_Is_empty(the_chain))
return _Chain_Get_first_unprotected(the_chain);
else
return NULL;
}
/** @brief Insert a Node (unprotected)
*
* This routine inserts the_node on a chain immediately following
* after_node.
*
* @param[in] after_node is the node which will precede @a the_node on the
* chain.
* @param[in] the_node is the node to be inserted.
*
* @note It does NOT disable interrupts to ensure the atomicity
* of the extract operation.
*/
RTEMS_INLINE_ROUTINE void _Chain_Insert_unprotected(
Chain_Node *after_node,
Chain_Node *the_node
)
{
Chain_Node *before_node;
the_node->previous = after_node;
before_node = after_node->next;
after_node->next = the_node;
the_node->next = before_node;
before_node->previous = the_node;
}
/** @brief Append a Node (unprotected)
*
* This routine appends the_node onto the end of the_chain.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to be appended.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* append operation.
*/
RTEMS_INLINE_ROUTINE void _Chain_Append_unprotected(
Chain_Control *the_chain,
Chain_Node *the_node
)
{
Chain_Node *tail = _Chain_Tail( the_chain );
Chain_Node *old_last = tail->previous;
the_node->next = tail;
tail->previous = the_node;
old_last->next = the_node;
the_node->previous = old_last;
}
/** @brief Prepend a Node (unprotected)
*
* This routine prepends the_node onto the front of the_chain.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to be prepended.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* prepend operation.
*/
RTEMS_INLINE_ROUTINE void _Chain_Prepend_unprotected(
Chain_Control *the_chain,
Chain_Node *the_node
)
{
_Chain_Insert_unprotected(_Chain_Head(the_chain), the_node);
}
/** @brief Prepend a Node (protected)
*
* This routine prepends the_node onto the front of the_chain.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to be prepended.
*
* @note It disables interrupts to ensure the atomicity of the
* prepend operation.
*/
RTEMS_INLINE_ROUTINE void _Chain_Prepend(
Chain_Control *the_chain,
Chain_Node *the_node
)
{
_Chain_Insert(_Chain_Head(the_chain), the_node);
}
/**
* @brief Append a node and check if the chain was empty before (unprotected).
*
* This routine appends the_node onto the end of the_chain.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to be appended.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* append operation.
*
* @retval true The chain was empty before.
* @retval false The chain contained at least one node before.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Append_with_empty_check_unprotected(
Chain_Control *the_chain,
Chain_Node *the_node
)
{
bool was_empty = _Chain_Is_empty( the_chain );
_Chain_Append_unprotected( the_chain, the_node );
return was_empty;
}
/**
* @brief Prepend a node and check if the chain was empty before (unprotected).
*
* This routine prepends the_node onto the front of the_chain.
*
* @param[in] the_chain is the chain to be operated upon.
* @param[in] the_node is the node to be prepended.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* prepend operation.
*
* @retval true The chain was empty before.
* @retval false The chain contained at least one node before.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Prepend_with_empty_check_unprotected(
Chain_Control *the_chain,
Chain_Node *the_node
)
{
bool was_empty = _Chain_Is_empty( the_chain );
_Chain_Prepend_unprotected( the_chain, the_node );
return was_empty;
}
/**
* @brief Get the first node and check if the chain is empty afterwards
* (unprotected).
*
* This function removes the first node from the_chain and returns
* a pointer to that node in @a the_node. If the_chain is empty, then NULL is
* returned.
*
* @param[in] the_chain is the chain to attempt to get the first node from.
* @param[out] the_node is the first node on the chain or NULL if the chain is
* empty.
*
* @note It does NOT disable interrupts to ensure the atomicity of the
* get operation.
*
* @retval true The chain is empty now.
* @retval false The chain contains at least one node now.
*/
RTEMS_INLINE_ROUTINE bool _Chain_Get_with_empty_check_unprotected(
Chain_Control *the_chain,
Chain_Node **the_node
)
{
bool is_empty_now = true;
Chain_Node *head = _Chain_Head( the_chain );
Chain_Node *tail = _Chain_Tail( the_chain );
Chain_Node *old_first = head->next;
if ( old_first != tail ) {
Chain_Node *new_first = old_first->next;
head->next = new_first;
new_first->previous = head;
*the_node = old_first;
is_empty_now = new_first == tail;
} else
*the_node = NULL;
return is_empty_now;
}
/**@}*/
#endif
/* end of include file */