2010-08-23 Sebastian Huber <sebastian.huber@embedded-brains.de>

	PR 1673/cpukit
	* score/src/chainappendempty.c, score/src/chaingetempty.c,
	score/src/chainprependempty.c: New files.
	* score/Makefile.am: Reflect changes above.
	* score/include/rtems/score/chain.h: Declare
	_Chain_Append_with_empty_check(), _Chain_Prepend_with_empty_check(),
	and _Chain_Get_with_empty_check().
	* score/inline/rtems/score/chain.inl: Define
	_Chain_Append_with_empty_check_unprotected(),
	_Chain_Prepend_with_empty_check_unprotected(), and
	_Chain_Get_with_empty_check_unprotected().

7 files changed, 313 insertions, 9 deletions

diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog
index 26c11faa63..85e1423e26 100644
--- a/cpukit/ChangeLog
+++ b/cpukit/ChangeLog
@@ -1,5 +1,19 @@
 2010-08-23	Sebastian Huber <sebastian.huber@embedded-brains.de>
 
+	PR 1673/cpukit
+	* score/src/chainappendempty.c, score/src/chaingetempty.c,
+	score/src/chainprependempty.c: New files.
+	* score/Makefile.am: Reflect changes above.
+	* score/include/rtems/score/chain.h: Declare
+	_Chain_Append_with_empty_check(), _Chain_Prepend_with_empty_check(),
+	and _Chain_Get_with_empty_check().
+	* score/inline/rtems/score/chain.inl: Define
+	_Chain_Append_with_empty_check_unprotected(),
+	_Chain_Prepend_with_empty_check_unprotected(), and
+	_Chain_Get_with_empty_check_unprotected().
+
+2010-08-23	Sebastian Huber <sebastian.huber@embedded-brains.de>
+
 	PR 1671/cpukit
 	* libcsupport/include/rtems/gxx_wrappers.h: New file.
 	* libcsupport/Makefile.am, libcsupport/preinstall.am: Reflect change
diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index 43d53e0526..fd1f2a90e2 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -200,6 +200,7 @@ libscore_a_SOURCES += src/userextaddset.c \
 ## STD_C_FILES
 libscore_a_SOURCES += src/apiext.c src/chain.c src/chainappend.c \
     src/chainextract.c src/chainget.c src/chaininsert.c \
+    src/chainappendempty.c src/chainprependempty.c src/chaingetempty.c \
     src/interr.c src/isr.c src/wkspace.c
 
 EXTRA_DIST = src/Unlimited.txt
diff --git a/cpukit/score/include/rtems/score/chain.h b/cpukit/score/include/rtems/score/chain.h
index 3d18adf64f..4d298b3cd2 100644
--- a/cpukit/score/include/rtems/score/chain.h
+++ b/cpukit/score/include/rtems/score/chain.h
@@ -1,11 +1,14 @@
 /**
- *  @file  rtems/score/chain.h
+ * @file
  *
- *  This include file contains all the constants and structures associated
- *  with the Doubly-Linked Chain Handler.
+ * @ingroup ScoreChain
+ *
+ * @brief Chain Handler API.
  */
 
 /*
+ *  Copyright (c) 2010 embedded brains GmbH.
+ *
  *  COPYRIGHT (c) 1989-2006.
  *  On-Line Applications Research Corporation (OAR).
  *
@@ -22,6 +25,8 @@
 /**
  *  @defgroup ScoreChain Chain Handler
  *
+ *  @ingroup Score
+ *
  *  The Chain Handler is used to manage sets of entities.  This handler
  *  provides two data structures.  The Chain Node data structure is included
  *  as the first part of every data structure that will be placed on
@@ -185,6 +190,66 @@ void _Chain_Append(
   Chain_Node    *the_node
 );
 
+/**
+ * @brief Append a node and check if the chain was empty before.
+ *
+ * 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 disables 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.
+ */
+bool _Chain_Append_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+);
+
+/**
+ * @brief Prepend a node and check if the chain was empty before.
+ *
+ * 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 append
+ * operation.
+ *
+ * @retval true The chain was empty before.
+ * @retval false The chain contained at least one node before.
+ */
+bool _Chain_Prepend_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+);
+
+/**
+ * @brief Get the first node and check if the chain is empty afterwards.
+ *
+ * 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 disables interrupts to ensure the atomicity of the append
+ * operation.
+ *
+ * @retval true The chain is empty now.
+ * @retval false The chain contains at least one node now.
+ */
+bool _Chain_Get_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node **the_node
+);
+
 #ifndef __RTEMS_APPLICATION__
 #include <rtems/score/chain.inl>
 #endif
diff --git a/cpukit/score/inline/rtems/score/chain.inl b/cpukit/score/inline/rtems/score/chain.inl
index 3bde7fb229..ae1b6e4024 100644
--- a/cpukit/score/inline/rtems/score/chain.inl
+++ b/cpukit/score/inline/rtems/score/chain.inl
@@ -1,15 +1,14 @@
 /**
- *  @file  rtems/score/chain.inl
+ * @file
  *
- *  This include file contains the bodies of the routines which are
- *  associated with doubly linked chains and inlined.
+ * @ingroup ScoreChain
  *
- *  @note  The routines in this file are ordered from simple
- *         to complex.  No other Chain Handler routine is referenced
- *         unless it has already been defined.
+ * @brief Chain Handler API.
  */
 
 /*
+ *  Copyright (c) 2010 embedded brains GmbH.
+ *
  *  COPYRIGHT (c) 1989-2006.
  *  On-Line Applications Research Corporation (OAR).
  *
@@ -481,6 +480,99 @@ RTEMS_INLINE_ROUTINE void _Chain_Prepend(
   _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 *first = the_chain->first;
+
+  if ( first != _Chain_Tail( the_chain ) ) {
+    Chain_Node *new_first = first->next;
+
+    the_chain->first = new_first;
+    new_first->previous = _Chain_Head( the_chain );
+
+    *the_node = first;
+
+    is_empty_now = new_first == _Chain_Tail( the_chain );
+  } else
+    *the_node = NULL;
+
+  return is_empty_now;
+}
+
 /**@}*/
 
 #endif
diff --git a/cpukit/score/src/chainappendempty.c b/cpukit/score/src/chainappendempty.c
new file mode 100644
index 0000000000..33033df8ed
--- /dev/null
+++ b/cpukit/score/src/chainappendempty.c
@@ -0,0 +1,44 @@
+/**
+ * @file
+ *
+ * @ingroup ScoreChain
+ *
+ * @brief _Chain_Append_with_empty_check() implementation.
+ */
+
+/*
+ * Copyright (c) 2010 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * 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.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/chain.h>
+#include <rtems/score/isr.h>
+
+bool _Chain_Append_with_empty_check(
+  Chain_Control *chain,
+  Chain_Node *node
+)
+{
+  ISR_Level level;
+  bool was_empty;
+
+  _ISR_Disable( level );
+  was_empty = _Chain_Append_with_empty_check_unprotected( chain, node );
+  _ISR_Enable( level );
+
+  return was_empty;
+}
diff --git a/cpukit/score/src/chaingetempty.c b/cpukit/score/src/chaingetempty.c
new file mode 100644
index 0000000000..3f9be4de5b
--- /dev/null
+++ b/cpukit/score/src/chaingetempty.c
@@ -0,0 +1,44 @@
+/**
+ * @file
+ *
+ * @ingroup ScoreChain
+ *
+ * @brief _Chain_Get_with_empty_check() implementation.
+ */
+
+/*
+ * Copyright (c) 2010 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * 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.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/chain.h>
+#include <rtems/score/isr.h>
+
+bool _Chain_Get_with_empty_check(
+  Chain_Control *chain,
+  Chain_Node **node
+)
+{
+  ISR_Level level;
+  bool is_empty_now;
+
+  _ISR_Disable( level );
+  is_empty_now = _Chain_Get_with_empty_check_unprotected( chain, node );
+  _ISR_Enable( level );
+
+  return is_empty_now;
+}
diff --git a/cpukit/score/src/chainprependempty.c b/cpukit/score/src/chainprependempty.c
new file mode 100644
index 0000000000..9dfd9a653f
--- /dev/null
+++ b/cpukit/score/src/chainprependempty.c
@@ -0,0 +1,44 @@
+/**
+ * @file
+ *
+ * @ingroup ScoreChain
+ *
+ * @brief _Chain_Prepend_with_empty_check() implementation.
+ */
+
+/*
+ * Copyright (c) 2010 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * 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.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/system.h>
+#include <rtems/score/chain.h>
+#include <rtems/score/isr.h>
+
+bool _Chain_Prepend_with_empty_check(
+  Chain_Control *chain,
+  Chain_Node *node
+)
+{
+  ISR_Level level;
+  bool was_empty;
+
+  _ISR_Disable( level );
+  was_empty = _Chain_Prepend_with_empty_check_unprotected( chain, node );
+  _ISR_Enable( level );
+
+  return was_empty;
+}