Diff: FreeRTOS/Source/include/list.h

Revision:

0:d4960fcea8ff

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+++ b/FreeRTOS/Source/include/list.h	Sat Jan 01 11:17:45 2011 +0000
@@ -0,0 +1,305 @@
+/*
+    FreeRTOS V6.0.3 - Copyright (C) 2010 Real Time Engineers Ltd.
+
+    ***************************************************************************
+    *                                                                         *
+    * If you are:                                                             *
+    *                                                                         *
+    *    + New to FreeRTOS,                                                   *
+    *    + Wanting to learn FreeRTOS or multitasking in general quickly       *
+    *    + Looking for basic training,                                        *
+    *    + Wanting to improve your FreeRTOS skills and productivity           *
+    *                                                                         *
+    * then take a look at the FreeRTOS eBook                                  *
+    *                                                                         *
+    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
+    *                  http://www.FreeRTOS.org/Documentation                  *
+    *                                                                         *
+    * A pdf reference manual is also available.  Both are usually delivered   *
+    * to your inbox within 20 minutes to two hours when purchased between 8am *
+    * and 8pm GMT (although please allow up to 24 hours in case of            *
+    * exceptional circumstances).  Thank you for your support!                *
+    *                                                                         *
+    ***************************************************************************
+
+    This file is part of the FreeRTOS distribution.
+
+    FreeRTOS is free software; you can redistribute it and/or modify it under
+    the terms of the GNU General Public License (version 2) as published by the
+    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
+    ***NOTE*** The exception to the GPL is included to allow you to distribute
+    a combined work that includes FreeRTOS without being obliged to provide the
+    source code for proprietary components outside of the FreeRTOS kernel.
+    FreeRTOS 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 General Public License for
+    more details. You should have received a copy of the GNU General Public 
+    License and the FreeRTOS license exception along with FreeRTOS; if not it 
+    can be viewed here: http://www.freertos.org/a00114.html and also obtained 
+    by writing to Richard Barry, contact details for whom are available on the
+    FreeRTOS WEB site.
+
+    1 tab == 4 spaces!
+
+    http://www.FreeRTOS.org - Documentation, latest information, license and
+    contact details.
+
+    http://www.SafeRTOS.com - A version that is certified for use in safety
+    critical systems.
+
+    http://www.OpenRTOS.com - Commercial support, development, porting,
+    licensing and training services.
+*/
+
+/*
+ * This is the list implementation used by the scheduler.  While it is tailored
+ * heavily for the schedulers needs, it is also available for use by
+ * application code.
+ *
+ * xLists can only store pointers to xListItems.  Each xListItem contains a
+ * numeric value (xItemValue).  Most of the time the lists are sorted in
+ * descending item value order.
+ *
+ * Lists are created already containing one list item.  The value of this
+ * item is the maximum possible that can be stored, it is therefore always at
+ * the end of the list and acts as a marker.  The list member pxHead always
+ * points to this marker - even though it is at the tail of the list.  This
+ * is because the tail contains a wrap back pointer to the true head of
+ * the list.
+ *
+ * In addition to it's value, each list item contains a pointer to the next
+ * item in the list (pxNext), a pointer to the list it is in (pxContainer)
+ * and a pointer to back to the object that contains it.  These later two
+ * pointers are included for efficiency of list manipulation.  There is
+ * effectively a two way link between the object containing the list item and
+ * the list item itself.
+ *
+ *
+ * \page ListIntroduction List Implementation
+ * \ingroup FreeRTOSIntro
+ */
+
+/*
+    Changes from V4.3.1
+
+    + Included local const within listGET_OWNER_OF_NEXT_ENTRY() to assist
+      compiler with optimisation.  Thanks B.R.
+*/
+
+#ifndef LIST_H
+#define LIST_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Definition of the only type of object that a list can contain.
+ */
+struct xLIST_ITEM
+{
+    portTickType xItemValue;                /*< The value being listed.  In most cases this is used to sort the list in descending order. */
+    volatile struct xLIST_ITEM * pxNext;    /*< Pointer to the next xListItem in the list. */
+    volatile struct xLIST_ITEM * pxPrevious;/*< Pointer to the previous xListItem in the list. */
+    void * pvOwner;                            /*< Pointer to the object (normally a TCB) that contains the list item.  There is therefore a two way link between the object containing the list item and the list item itself. */
+    void * pvContainer;                        /*< Pointer to the list in which this list item is placed (if any). */
+};
+typedef struct xLIST_ITEM xListItem;        /* For some reason lint wants this as two separate definitions. */
+
+struct xMINI_LIST_ITEM
+{
+    portTickType xItemValue;
+    volatile struct xLIST_ITEM *pxNext;
+    volatile struct xLIST_ITEM *pxPrevious;
+};
+typedef struct xMINI_LIST_ITEM xMiniListItem;
+
+/*
+ * Definition of the type of queue used by the scheduler.
+ */
+typedef struct xLIST
+{
+    volatile unsigned portBASE_TYPE uxNumberOfItems;
+    volatile xListItem * pxIndex;            /*< Used to walk through the list.  Points to the last item returned by a call to pvListGetOwnerOfNextEntry (). */
+    volatile xMiniListItem xListEnd;        /*< List item that contains the maximum possible item value meaning it is always at the end of the list and is therefore used as a marker. */
+} xList;
+
+/*
+ * Access macro to set the owner of a list item.  The owner of a list item
+ * is the object (usually a TCB) that contains the list item.
+ *
+ * \page listSET_LIST_ITEM_OWNER listSET_LIST_ITEM_OWNER
+ * \ingroup LinkedList
+ */
+#define listSET_LIST_ITEM_OWNER( pxListItem, pxOwner )        ( pxListItem )->pvOwner = ( void * ) pxOwner
+
+/*
+ * Access macro to set the value of the list item.  In most cases the value is
+ * used to sort the list in descending order.
+ *
+ * \page listSET_LIST_ITEM_VALUE listSET_LIST_ITEM_VALUE
+ * \ingroup LinkedList
+ */
+#define listSET_LIST_ITEM_VALUE( pxListItem, xValue )        ( pxListItem )->xItemValue = xValue
+
+/*
+ * Access macro the retrieve the value of the list item.  The value can
+ * represent anything - for example a the priority of a task, or the time at
+ * which a task should be unblocked.
+ *
+ * \page listGET_LIST_ITEM_VALUE listGET_LIST_ITEM_VALUE
+ * \ingroup LinkedList
+ */
+#define listGET_LIST_ITEM_VALUE( pxListItem )                ( ( pxListItem )->xItemValue )
+
+/*
+ * Access macro to determine if a list contains any items.  The macro will
+ * only have the value true if the list is empty.
+ *
+ * \page listLIST_IS_EMPTY listLIST_IS_EMPTY
+ * \ingroup LinkedList
+ */
+#define listLIST_IS_EMPTY( pxList )                ( ( pxList )->uxNumberOfItems == ( unsigned portBASE_TYPE ) 0 )
+
+/*
+ * Access macro to return the number of items in the list.
+ */
+#define listCURRENT_LIST_LENGTH( pxList )        ( ( pxList )->uxNumberOfItems )
+
+/*
+ * Access function to obtain the owner of the next entry in a list.
+ *
+ * The list member pxIndex is used to walk through a list.  Calling
+ * listGET_OWNER_OF_NEXT_ENTRY increments pxIndex to the next item in the list
+ * and returns that entries pxOwner parameter.  Using multiple calls to this
+ * function it is therefore possible to move through every item contained in
+ * a list.
+ *
+ * The pxOwner parameter of a list item is a pointer to the object that owns
+ * the list item.  In the scheduler this is normally a task control block.
+ * The pxOwner parameter effectively creates a two way link between the list
+ * item and its owner.
+ *
+ * @param pxList The list from which the next item owner is to be returned.
+ *
+ * \page listGET_OWNER_OF_NEXT_ENTRY listGET_OWNER_OF_NEXT_ENTRY
+ * \ingroup LinkedList
+ */
+// Modified by  Kenji Arai / JH1PJL, October 31st,2010
+#define listGET_OWNER_OF_NEXT_ENTRY( pxTCB, pxList )                                    \
+{                                                                                        \
+xList * const pxConstList = pxList;                                                        \
+    /* Increment the index to the next item and return the item, ensuring */            \
+    /* we don't return the marker used at the end of the list.  */                        \
+    ( pxConstList )->pxIndex = ( pxConstList )->pxIndex->pxNext;                        \
+    if( ( pxConstList )->pxIndex == ( xListItem * ) &( ( pxConstList )->xListEnd ) )    \
+    {                                                                                    \
+        ( pxConstList )->pxIndex = ( pxConstList )->pxIndex->pxNext;                    \
+    }                                                                                    \
+    pxTCB = (tskTCB *)(( pxConstList )->pxIndex->pvOwner);                                \
+}
+
+/*
+ * Access function to obtain the owner of the first entry in a list.  Lists
+ * are normally sorted in ascending item value order.
+ *
+ * This function returns the pxOwner member of the first item in the list.
+ * The pxOwner parameter of a list item is a pointer to the object that owns
+ * the list item.  In the scheduler this is normally a task control block.
+ * The pxOwner parameter effectively creates a two way link between the list
+ * item and its owner.
+ *
+ * @param pxList The list from which the owner of the head item is to be
+ * returned.
+ *
+ * \page listGET_OWNER_OF_HEAD_ENTRY listGET_OWNER_OF_HEAD_ENTRY
+ * \ingroup LinkedList
+ */
+#define listGET_OWNER_OF_HEAD_ENTRY( pxList )  ( ( pxList->uxNumberOfItems != ( unsigned portBASE_TYPE ) 0 ) ? ( (&( pxList->xListEnd ))->pxNext->pvOwner ) : ( NULL ) )
+
+/*
+ * Check to see if a list item is within a list.  The list item maintains a
+ * "container" pointer that points to the list it is in.  All this macro does
+ * is check to see if the container and the list match.
+ *
+ * @param pxList The list we want to know if the list item is within.
+ * @param pxListItem The list item we want to know if is in the list.
+ * @return pdTRUE is the list item is in the list, otherwise pdFALSE.
+ * pointer against
+ */
+#define listIS_CONTAINED_WITHIN( pxList, pxListItem ) ( ( pxListItem )->pvContainer == ( void * ) pxList )
+
+/*
+ * Must be called before a list is used!  This initialises all the members
+ * of the list structure and inserts the xListEnd item into the list as a
+ * marker to the back of the list.
+ *
+ * @param pxList Pointer to the list being initialised.
+ *
+ * \page vListInitialise vListInitialise
+ * \ingroup LinkedList
+ */
+void vListInitialise( xList *pxList );
+
+/*
+ * Must be called before a list item is used.  This sets the list container to
+ * null so the item does not think that it is already contained in a list.
+ *
+ * @param pxItem Pointer to the list item being initialised.
+ *
+ * \page vListInitialiseItem vListInitialiseItem
+ * \ingroup LinkedList
+ */
+void vListInitialiseItem( xListItem *pxItem );
+
+/*
+ * Insert a list item into a list.  The item will be inserted into the list in
+ * a position determined by its item value (descending item value order).
+ *
+ * @param pxList The list into which the item is to be inserted.
+ *
+ * @param pxNewListItem The item to that is to be placed in the list.
+ *
+ * \page vListInsert vListInsert
+ * \ingroup LinkedList
+ */
+void vListInsert( xList *pxList, xListItem *pxNewListItem );
+
+/*
+ * Insert a list item into a list.  The item will be inserted in a position
+ * such that it will be the last item within the list returned by multiple
+ * calls to listGET_OWNER_OF_NEXT_ENTRY.
+ *
+ * The list member pvIndex is used to walk through a list.  Calling
+ * listGET_OWNER_OF_NEXT_ENTRY increments pvIndex to the next item in the list.
+ * Placing an item in a list using vListInsertEnd effectively places the item
+ * in the list position pointed to by pvIndex.  This means that every other
+ * item within the list will be returned by listGET_OWNER_OF_NEXT_ENTRY before
+ * the pvIndex parameter again points to the item being inserted.
+ *
+ * @param pxList The list into which the item is to be inserted.
+ *
+ * @param pxNewListItem The list item to be inserted into the list.
+ *
+ * \page vListInsertEnd vListInsertEnd
+ * \ingroup LinkedList
+ */
+void vListInsertEnd( xList *pxList, xListItem *pxNewListItem );
+
+/*
+ * Remove an item from a list.  The list item has a pointer to the list that
+ * it is in, so only the list item need be passed into the function.
+ *
+ * @param vListRemove The item to be removed.  The item will remove itself from
+ * the list pointed to by it's pxContainer parameter.
+ *
+ * \page vListRemove vListRemove
+ * \ingroup LinkedList
+ */
+void vListRemove( xListItem *pxItemToRemove );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+