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 /* SPDX-License-Identifier: BSD-2-Clause */
 
 /**
  * @file
  * 
  * @ingroup RTEMSAPIClassicChains
  *
  * @brief This header file provides the Chains API.
  */
 
 /*
  *  Copyright (C) 2010, 2014 embedded brains GmbH & Co. KG
  *
  *  COPYRIGHT (c) 1989-2008.
  *  On-Line Applications Research Corporation (OAR).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef _RTEMS_CHAIN_H
 #define _RTEMS_CHAIN_H
 
 #include <rtems/score/chainimpl.h>
 #include <rtems/rtems/event.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /**
  * @defgroup RTEMSAPIClassicChains Chains
  *
  * @ingroup RTEMSAPIClassic
  *
  * @brief The chain container provides data structures and directives to manage
  *   user-defined data structures in doubly-linked lists.
  *
  * @{
  */
 
 typedef Chain_Node rtems_chain_node;
 
 typedef Chain_Control rtems_chain_control;
 
 /**
  *  @brief Chain initializer for an empty chain with designator @a name.
  */
 #define RTEMS_CHAIN_INITIALIZER_EMPTY( name ) \
   CHAIN_INITIALIZER_EMPTY( name )
 
 /**
  *  @brief Chain initializer for a chain with one @a node.
  *
  *  @see RTEMS_CHAIN_NODE_INITIALIZER_ONE_NODE_CHAIN().
  */
 #define RTEMS_CHAIN_INITIALIZER_ONE_NODE( node ) \
   CHAIN_INITIALIZER_ONE_NODE( node )
 
 /**
  *  @brief Chain node initializer for a @a chain containing exactly this node.
  *
  *  @see RTEMS_CHAIN_INITIALIZER_ONE_NODE().
  */
 #define RTEMS_CHAIN_NODE_INITIALIZER_ONE_NODE_CHAIN( chain ) \
   CHAIN_NODE_INITIALIZER_ONE_NODE_CHAIN( chain )
 
 /**
  *  @brief Chain definition for an empty chain with designator @a name.
  */
 #define RTEMS_CHAIN_DEFINE_EMPTY( name ) \
   rtems_chain_control name = RTEMS_CHAIN_INITIALIZER_EMPTY( name )
 
 /**
  * @brief Appends the @a node to the @a chain and sends the @a events to the
  * @a task if the @a chain was empty before the append.
  *
  * @see rtems_chain_append_with_empty_check() and rtems_event_send().
  *
  * @retval RTEMS_SUCCESSFUL Successful operation.
  * @retval RTEMS_INVALID_ID No such task.
  */
 rtems_status_code rtems_chain_append_with_notification(
   rtems_chain_control *chain,
   rtems_chain_node *node,
   rtems_id task,
   rtems_event_set events
 );
 
 /**
  * @brief Prepends the @a node to the @a chain and sends the @a events to the
  * @a task if the @a chain was empty before the prepend.
  *
  * @see rtems_chain_prepend_with_empty_check() and rtems_event_send().
  *
  * @retval RTEMS_SUCCESSFUL Successful operation.
  * @retval RTEMS_INVALID_ID No such task.
  */
 rtems_status_code rtems_chain_prepend_with_notification(
   rtems_chain_control *chain,
   rtems_chain_node *node,
   rtems_id task,
   rtems_event_set events
 );
 
 /**
  * @brief Gets the first @a node of the @a chain and sends the @a events to the
  * @a task if the @a chain is empty after the get.
  *
  * @see rtems_chain_get_with_empty_check() and rtems_event_send().
  *
  * @retval RTEMS_SUCCESSFUL Successful operation.
  * @retval RTEMS_INVALID_ID No such task.
  */
 rtems_status_code rtems_chain_get_with_notification(
   rtems_chain_control *chain,
   rtems_id task,
   rtems_event_set events,
   rtems_chain_node **node
 );
 
 /**
  * @brief Gets the first @a node of the @a chain and sends the @a events to the
  * @a task if the @a chain is empty afterwards.
  *
  * @see rtems_chain_get() and rtems_event_receive().
  *
  * @retval RTEMS_SUCCESSFUL Successful operation.
  * @retval RTEMS_TIMEOUT Timeout.
  */
 rtems_status_code rtems_chain_get_with_wait(
   rtems_chain_control *chain,
   rtems_event_set events,
   rtems_interval timeout,
   rtems_chain_node **node
 );
 
 /**
  * @brief Initialize a chain Header.
  *
  * This routine initializes @a the_chain structure to manage the
  * contiguous array of @a number_nodes nodes which starts at
  * @a starting_address.  Each node is of @a node_size bytes.
  *
  * @param[in] the_chain specifies the chain to initialize
  * @param[in] starting_address is the starting address of the array
  *        of elements
  * @param[in] number_nodes is the number of nodes that will be in the chain
  * @param[in] node_size is the size of each node
  */
 static inline void rtems_chain_initialize(
   rtems_chain_control *the_chain,
   void                *starting_address,
   size_t               number_nodes,
   size_t               node_size
 )
 {
   _Chain_Initialize(
     the_chain,
     starting_address,
     number_nodes,
     node_size
   );
 }
 
 /**
  * @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.
  */
 static inline void rtems_chain_initialize_empty(
   rtems_chain_control *the_chain
 )
 {
   _Chain_Initialize_empty( the_chain );
 }
 
 /**
  * @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.
  */
 static inline void rtems_chain_set_off_chain(
   rtems_chain_node *node
 )
 {
   _Chain_Set_off_chain( node );
 }
 
 /**
  * @brief Initializes a chain node.
  *
  * In debug configurations, the node is set off chain.  In all other
  * configurations, this function does nothing.
  *
  * @param[in] the_node The chain node to initialize.
  */
 static inline void rtems_chain_initialize_node(
   rtems_chain_node *node
 )
 {
   _Chain_Initialize_node( node );
 }
 
 /**
  * @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.
  *
  * @retval true The node is off chain.
  * @retval false The node is not off chain.
  */
 static inline bool rtems_chain_is_node_off_chain(
   const rtems_chain_node *node
 )
 {
   return _Chain_Is_node_off_chain( node );
 }
 
 /**
  * @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.
  * 
  * @retval true The chain node pointer is NULL.
  * @retval false The chain node pointer is not NULL.
  */
 static inline bool rtems_chain_is_null_node(
   const rtems_chain_node *the_node
 )
 {
   return the_node == NULL;
 }
 
 /**
  * @brief Return pointer to Chain Head
  *
  * This function returns a pointer to the first node on the chain.
  *
  * @param[in] the_chain is the chain to be operated upon.
  *
  * @return This method returns the permanent node of the chain.
  */
 static inline rtems_chain_node *rtems_chain_head(
   rtems_chain_control *the_chain
 )
 {
   return _Chain_Head( the_chain );
 }
 
 /**
  * @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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_head(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Immutable_head( the_chain );
 }
 
 /**
  * @brief Return pointer to Chain Tail
  *
  * This function returns a pointer to the tail 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.
  */
 static inline rtems_chain_node *rtems_chain_tail(
   rtems_chain_control *the_chain
 )
 {
   return _Chain_Tail( the_chain );
 }
 
 /** 
  * @brief Return pointer to immutable Chain Tail
  *
  * This function returns a pointer to the tail 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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_tail(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Immutable_tail( the_chain );
 }
 
 /**
  * @brief Return pointer to Chain's First node after the permanent head.
  *
  * 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.
  */
 static inline rtems_chain_node *rtems_chain_first(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_First( the_chain );
 }
 
 /** 
  * @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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_first(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Immutable_first( the_chain );
 }
 
 /**
  * @brief Return pointer to Chain's Last node before the permanent tail.
  *
  * 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.
  */
 static inline rtems_chain_node *rtems_chain_last(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Last( the_chain );
 }
 
 /**
  * @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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_last(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Immutable_last( the_chain );
 }
 
 /**
  * @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.
  */
 static inline rtems_chain_node *rtems_chain_next(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Next( the_node );
 }
 
 /** 
  * @brief Return pointer the immutable 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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_next(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Immutable_next( the_node );
 }
 
 /**
  * @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.
  */
 static inline rtems_chain_node *rtems_chain_previous(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Previous( the_node );
 }
 
 /**
  * @brief Return pointer the immutable 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.
  */
 static inline const rtems_chain_node *rtems_chain_immutable_previous(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Immutable_previous( the_node );
 }
 
 /**
  * @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.
  *
  * @retval true @a left is equal to @a right.
  * @retval false @a left is not equal to @a right
  */
 static inline bool rtems_chain_are_nodes_equal(
   const rtems_chain_node *left,
   const rtems_chain_node *right
 )
 {
   return _Chain_Are_nodes_equal( left, right );
 }
 
 /**
  * @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.
  *
  * @retval true The chain is empty.
  * @retval false The chain is not empty.
  */
 static inline bool rtems_chain_is_empty(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Is_empty( 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.
  *
  * @retval true @a the_node is the first node on a chain.
  * @retval false @a the_node is not the first node on a chain.
  */
 static inline bool rtems_chain_is_first(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Is_first( the_node );
 }
 
 /**
  * @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.
  *
  * @retval true @a the_node is the last node on a chain.
  * @retval false @a the_node is not the last node on a chain
  */
 static inline bool rtems_chain_is_last(
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Is_last( the_node );
 }
 
 /**
  * @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.
  *
  * @retval true The chain has only one node.
  * @retval false The chain has more than one nodes.
  */
 static inline bool rtems_chain_has_only_one_node(
   const rtems_chain_control *the_chain
 )
 {
   return _Chain_Has_only_one_node( 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.
  *
  * @retval true @a the_node is the head of @a the_chain.
  * @retval false @a the_node is not the head of @a the_chain.
  */
 static inline bool rtems_chain_is_head(
   const rtems_chain_control *the_chain,
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Is_head( the_chain, the_node );
 }
 
 /**
  * @brief Is this node the chain 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.
  * 
  * @retval true @a the_node is the tail of @a the_chain.
  * @retval false @a the_node is not the tail of @a the_chain.
  */
 static inline bool rtems_chain_is_tail(
   const rtems_chain_control *the_chain,
   const rtems_chain_node *the_node
 )
 {
   return _Chain_Is_tail( the_chain, the_node );
 }
 
 /**
  * @brief Extract the specified node from a chain.
  *
  * This routine extracts @a the_node from the chain on which it resides.
  * It disables interrupts to ensure the atomicity of the
  * extract operation.
  *
  * @arg the_node specifies the node to extract
  */
 void rtems_chain_extract(
   rtems_chain_node *the_node
 );
 
 /**
  * @brief Extract the specified node from a chain (unprotected).
  *
  * This routine extracts @a the_node from the chain on which it resides.
  *
  * NOTE: It does NOT disable interrupts to ensure the atomicity of the
  * append operation.
  */
 static inline void rtems_chain_extract_unprotected(
   rtems_chain_node *the_node
 )
 {
   _Chain_Extract_unprotected( the_node );
 }
 
 /**
  * @brief Obtain the first node on a chain.
  *
  * This function removes the first node from @a the_chain and returns
  * a pointer to that node.  If @a the_chain is empty, then NULL is returned.
  *
  * @return This method returns a pointer a node.  If a node was removed,
  *         then a pointer to that node is returned.  If @a the_chain was
  *         empty, then NULL is returned.
  *
  *  NOTE: It disables interrupts to ensure the atomicity of the get operation.
  */
 rtems_chain_node *rtems_chain_get(
   rtems_chain_control *the_chain
 );
 
 /**
  * @brief See _Chain_Get_unprotected().
  */
 static inline rtems_chain_node *rtems_chain_get_unprotected(
   rtems_chain_control *the_chain
 )
 {
   return _Chain_Get_unprotected( the_chain );
 }
 
 /**
  * @brief See _Chain_Get_first_unprotected().
  */
 static inline rtems_chain_node *rtems_chain_get_first_unprotected(
   rtems_chain_control *the_chain
 )
 {
   return _Chain_Get_first_unprotected( the_chain );
 }
 
 /**
  * @brief Insert a node on a chain
  *
  * This routine inserts @a the_node on a chain immediately following
  * @a after_node.  
  *
  * NOTE: It disables interrupts to ensure the atomicity
  * of the extract operation.
  */
 void rtems_chain_insert(
   rtems_chain_node *after_node,
   rtems_chain_node *the_node
 );
 
 /**
  * @brief See _Chain_Insert_unprotected().
  */
 static inline void rtems_chain_insert_unprotected(
   rtems_chain_node *after_node,
   rtems_chain_node *the_node
 )
 {
   _Chain_Insert_unprotected( after_node, the_node );
 }
 
 /**
  * @brief Append a node on the end of a chain.
  *
  * This routine appends @a the_node onto the end of @a the_chain.
  *
  * NOTE: It disables interrupts to ensure the atomicity of the
  * append operation.
  */
 void rtems_chain_append(
   rtems_chain_control *the_chain,
   rtems_chain_node    *the_node
 );
 
 /**
  * @brief Append a node on the end of a chain (unprotected).
  *
  * This routine appends @a the_node onto the end of @a the_chain.
  *
  * NOTE: It does NOT disable interrupts to ensure the atomicity of the
  * append operation.
  */
 static inline void rtems_chain_append_unprotected(
   rtems_chain_control *the_chain,
   rtems_chain_node    *the_node
 )
 {
   _Chain_Append_unprotected( the_chain, the_node );
 }
 
 /** 
  * @brief Prepend a node.
  *
  * 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.
  */
 void rtems_chain_prepend(
   rtems_chain_control *the_chain,
   rtems_chain_node    *the_node
 );
 
 /** 
  * @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.
  */
 static inline void rtems_chain_prepend_unprotected(
   rtems_chain_control *the_chain,
   rtems_chain_node    *the_node
 )
 {
   _Chain_Prepend_unprotected( the_chain, the_node );
 }
 
 /**
  * @brief Checks if the @a chain is empty and appends the @a node.
  *
  * Interrupts are disabled to ensure the atomicity of the operation.
  *
  * @retval true The chain was empty before the append.
  * @retval false The chain contained at least one node before the append.
  */
 bool rtems_chain_append_with_empty_check(
   rtems_chain_control *chain,
   rtems_chain_node *node
 );
 
 /**
  * @brief Checks if the @a chain is empty and prepends the @a node.
  *
  * Interrupts are disabled to ensure the atomicity of the operation.
  *
  * @retval true The chain was empty before the prepend.
  * @retval false The chain contained at least one node before the prepend.
  */
 bool rtems_chain_prepend_with_empty_check(
   rtems_chain_control *chain,
   rtems_chain_node *node
 );
 
 /**
  * @brief Tries to get the first @a node and check if the @a chain is empty
  * afterwards.
  *
  * This function removes the first node from the @a chain and returns a pointer
  * to that node in @a node.  If the @a chain is empty, then @c NULL is returned.
  *
  * Interrupts are disabled to ensure the atomicity of the operation.
  *
  * @retval true The chain is empty after the node removal.
  * @retval false The chain contained at least one node after the node removal.
  */
 bool rtems_chain_get_with_empty_check(
   rtems_chain_control *chain,
   rtems_chain_node **node
 );
 
 /**
  * @brief Returns the node count of the chain.
  *
  * @param[in] chain The chain.
  *
  * @note It does NOT disable interrupts to ensure the atomicity of the
  * operation.
  *
  * @return The node count of the chain.
  */
 static inline size_t rtems_chain_node_count_unprotected(
   const rtems_chain_control *chain
 )
 {
   return _Chain_Node_count_unprotected( chain );
 }
 
 /** @} */
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif
 /* end of include file */

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