MdePkg: introduce OrderedCollectionLib library class

This library class provides a set of APIs to manage an ordered collection
of items:
- Init(),
- UnInit(),
- Insert(),
- Delete(),
- IsEmpty(),
- Next(),
- Prev(),
- Min(),
- Max(),
- Find(),
- UserStruct().

There are many ways to implement an ordered collection. Depending on the
frequency of the different actions, different internal implementations may
have different performance, memory overhead, or code size.

Developers can select the library instance for a platform or module in
their DSC files that meets the needs of that platform or module.

Commit-message-from: "Kinney, Michael D" <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15790 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 434 insertions, 0 deletions

diff --git a/MdePkg/Include/Library/OrderedCollectionLib.h b/MdePkg/Include/Library/OrderedCollectionLib.h
new file mode 100644
index 0000000000..fc45d6dab7
--- /dev/null
+++ b/MdePkg/Include/Library/OrderedCollectionLib.h
@@ -0,0 +1,425 @@
+/** @file

+  An ordered collection library interface.

+

+  The library class provides a set of APIs to manage an ordered collection of

+  items.

+

+  Copyright (C) 2014, Red Hat, Inc.

+

+  This program and the accompanying materials are licensed and made available

+  under the terms and conditions of the BSD License that accompanies this

+  distribution. The full text of the license may be found at

+  http://opensource.org/licenses/bsd-license.php.

+

+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT

+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

+**/

+

+#ifndef __ORDERED_COLLECTION_LIB__

+#define __ORDERED_COLLECTION_LIB__

+

+#include <Base.h>

+

+//

+// Opaque structure for a collection.

+//

+typedef struct ORDERED_COLLECTION ORDERED_COLLECTION;

+

+//

+// Opaque structure for collection entries.

+//

+// Collection entries do not take ownership of the associated user structures,

+// they only link them. This makes it easy to link the same user structure into

+// several collections. If reference counting is required, the caller is

+// responsible for implementing it, as part of the user structure.

+//

+// A pointer-to-ORDERED_COLLECTION_ENTRY is considered an "iterator". Multiple,

+// simultaneous iterations are supported.

+//

+typedef struct ORDERED_COLLECTION_ENTRY ORDERED_COLLECTION_ENTRY;

+

+//

+// Altering the key field of an in-collection user structure (ie. the portion

+// of the user structure that ORDERED_COLLECTION_USER_COMPARE and

+// ORDERED_COLLECTION_KEY_COMPARE, below, read) is not allowed in-place. The

+// caller is responsible for bracketing the key change with the deletion and

+// the reinsertion of the user structure, so that the changed key value is

+// reflected in the collection.

+//

+

+/**

+  Comparator function type for two user structures.

+

+  @param[in] UserStruct1  Pointer to the first user structure.

+

+  @param[in] UserStruct2  Pointer to the second user structure.

+

+  @retval <0  If UserStruct1 compares less than UserStruct2.

+

+  @retval  0  If UserStruct1 compares equal to UserStruct2.

+

+  @retval >0  If UserStruct1 compares greater than UserStruct2.

+**/

+typedef

+INTN

+(EFIAPI *ORDERED_COLLECTION_USER_COMPARE)(

+  IN CONST VOID *UserStruct1,

+  IN CONST VOID *UserStruct2

+  );

+

+/**

+  Compare a standalone key against a user structure containing an embedded key.

+

+  @param[in] StandaloneKey  Pointer to the bare key.

+

+  @param[in] UserStruct     Pointer to the user structure with the embedded

+                            key.

+

+  @retval <0  If StandaloneKey compares less than UserStruct's key.

+

+  @retval  0  If StandaloneKey compares equal to UserStruct's key.

+

+  @retval >0  If StandaloneKey compares greater than UserStruct's key.

+**/

+typedef

+INTN

+(EFIAPI *ORDERED_COLLECTION_KEY_COMPARE)(

+  IN CONST VOID *StandaloneKey,

+  IN CONST VOID *UserStruct

+  );

+

+

+//

+// Some functions below are read-only, while others are read-write. If any

+// write operation is expected to run concurrently with any other operation on

+// the same collection, then the caller is responsible for implementing locking

+// for the whole collection.

+//

+

+/**

+  Retrieve the user structure linked by the specified collection entry.

+

+  Read-only operation.

+

+  @param[in] Entry  Pointer to the collection entry whose associated user

+                    structure we want to retrieve. The caller is responsible

+                    for passing a non-NULL argument.

+

+  @return  Pointer to user structure linked by Entry.

+**/

+VOID *

+EFIAPI

+OrderedCollectionUserStruct (

+  IN CONST ORDERED_COLLECTION_ENTRY *Entry

+  );

+

+

+/**

+  Allocate and initialize the ORDERED_COLLECTION structure.

+

+  @param[in]  UserStructCompare  This caller-provided function will be used to

+                                 order two user structures linked into the

+                                 collection, during the insertion procedure.

+

+  @param[in]  KeyCompare         This caller-provided function will be used to

+                                 order the standalone search key against user

+                                 structures linked into the collection, during

+                                 the lookup procedure.

+

+  @retval NULL  If allocation failed.

+

+  @return       Pointer to the allocated, initialized ORDERED_COLLECTION

+                structure, otherwise.

+**/

+ORDERED_COLLECTION *

+EFIAPI

+OrderedCollectionInit (

+  IN ORDERED_COLLECTION_USER_COMPARE UserStructCompare,

+  IN ORDERED_COLLECTION_KEY_COMPARE  KeyCompare

+  );

+

+

+/**

+  Check whether the collection is empty (has no entries).

+

+  Read-only operation.

+

+  @param[in] Collection  The collection to check for emptiness.

+

+  @retval TRUE   The collection is empty.

+

+  @retval FALSE  The collection is not empty.

+**/

+BOOLEAN

+EFIAPI

+OrderedCollectionIsEmpty (

+  IN CONST ORDERED_COLLECTION *Collection

+  );

+

+

+/**

+  Uninitialize and release an empty ORDERED_COLLECTION structure.

+

+  Read-write operation.

+

+  It is the caller's responsibility to delete all entries from the collection

+  before calling this function.

+

+  @param[in] Collection  The empty collection to uninitialize and release.

+**/

+VOID

+EFIAPI

+OrderedCollectionUninit (

+  IN ORDERED_COLLECTION *Collection

+  );

+

+

+/**

+  Look up the collection entry that links the user structure that matches the

+  specified standalone key.

+

+  Read-only operation.

+

+  @param[in] Collection     The collection to search for StandaloneKey.

+

+  @param[in] StandaloneKey  The key to locate among the user structures linked

+                            into Collection. StandaloneKey will be passed to

+                            ORDERED_COLLECTION_KEY_COMPARE.

+

+  @retval NULL  StandaloneKey could not be found.

+

+  @return       The collection entry that links to the user structure matching

+                StandaloneKey, otherwise.

+**/

+ORDERED_COLLECTION_ENTRY *

+EFIAPI

+OrderedCollectionFind (

+  IN CONST ORDERED_COLLECTION *Collection,

+  IN CONST VOID               *StandaloneKey

+  );

+

+

+/**

+  Find the collection entry of the minimum user structure stored in the

+  collection.

+

+  Read-only operation.

+

+  @param[in] Collection  The collection to return the minimum entry of. The

+                         user structure linked by the minimum entry compares

+                         less than all other user structures in the collection.

+

+  @retval NULL  If Collection is empty.

+

+  @return       The collection entry that links the minimum user structure,

+                otherwise.

+**/

+ORDERED_COLLECTION_ENTRY *

+EFIAPI

+OrderedCollectionMin (

+  IN CONST ORDERED_COLLECTION *Collection

+  );

+

+

+/**

+  Find the collection entry of the maximum user structure stored in the

+  collection.

+

+  Read-only operation.

+

+  @param[in] Collection  The collection to return the maximum entry of. The

+                         user structure linked by the maximum entry compares

+                         greater than all other user structures in the

+                         collection.

+

+  @retval NULL  If Collection is empty.

+

+  @return       The collection entry that links the maximum user structure,

+                otherwise.

+**/

+ORDERED_COLLECTION_ENTRY *

+EFIAPI

+OrderedCollectionMax (

+  IN CONST ORDERED_COLLECTION *Collection

+  );

+

+

+/**

+  Get the collection entry of the least user structure that is greater than the

+  one linked by Entry.

+

+  Read-only operation.

+

+  @param[in] Entry  The entry to get the successor entry of.

+

+  @retval NULL  If Entry is NULL, or Entry is the maximum entry of its

+                containing collection (ie. Entry has no successor entry).

+

+  @return       The collection entry linking the least user structure that is

+                greater than the one linked by Entry, otherwise.

+**/

+ORDERED_COLLECTION_ENTRY *

+EFIAPI

+OrderedCollectionNext (

+  IN CONST ORDERED_COLLECTION_ENTRY *Entry

+  );

+

+

+/**

+  Get the collection entry of the greatest user structure that is less than the

+  one linked by Entry.

+

+  Read-only operation.

+

+  @param[in] Entry  The entry to get the predecessor entry of.

+

+  @retval NULL  If Entry is NULL, or Entry is the minimum entry of its

+                containing collection (ie. Entry has no predecessor entry).

+

+  @return       The collection entry linking the greatest user structure that

+                is less than the one linked by Entry, otherwise.

+**/

+ORDERED_COLLECTION_ENTRY *

+EFIAPI

+OrderedCollectionPrev (

+  IN CONST ORDERED_COLLECTION_ENTRY *Entry

+  );

+

+

+/**

+  Insert (link) a user structure into the collection, allocating a new

+  collection entry.

+

+  Read-write operation.

+

+  @param[in,out] Collection  The collection to insert UserStruct into.

+

+  @param[out]    Entry       The meaning of this optional, output-only

+                             parameter depends on the return value of the

+                             function.

+

+                             When insertion is successful (RETURN_SUCCESS),

+                             Entry is set on output to the new collection entry

+                             that now links UserStruct.

+

+                             When insertion fails due to lack of memory

+                             (RETURN_OUT_OF_RESOURCES), Entry is not changed.

+

+                             When insertion fails due to key collision (ie.

+                             another user structure is already in the

+                             collection that compares equal to UserStruct),

+                             with return value RETURN_ALREADY_STARTED, then

+                             Entry is set on output to the entry that links the

+                             colliding user structure. This enables

+                             "find-or-insert" in one function call, or helps

+                             with later removal of the colliding element.

+

+  @param[in]     UserStruct  The user structure to link into the collection.

+                             UserStruct is ordered against in-collection user

+                             structures with the

+                             ORDERED_COLLECTION_USER_COMPARE function.

+

+  @retval RETURN_SUCCESS           Insertion successful. A new collection entry

+                                   has been allocated, linking UserStruct. The

+                                   new collection entry is reported back in

+                                   Entry (if the caller requested it).

+

+                                   Existing ORDERED_COLLECTION_ENTRY pointers

+                                   into Collection remain valid. For example,

+                                   on-going iterations in the caller can

+                                   continue with OrderedCollectionNext() /

+                                   OrderedCollectionPrev(), and they will

+                                   return the new entry at some point if user

+                                   structure order dictates it.

+

+  @retval RETURN_OUT_OF_RESOURCES  The function failed to allocate memory for

+                                   the new collection entry. The collection has

+                                   not been changed. Existing

+                                   ORDERED_COLLECTION_ENTRY pointers into

+                                   Collection remain valid.

+

+  @retval RETURN_ALREADY_STARTED   A user structure has been found in the

+                                   collection that compares equal to

+                                   UserStruct. The entry linking the colliding

+                                   user structure is reported back in Entry (if

+                                   the caller requested it). The collection has

+                                   not been changed. Existing

+                                   ORDERED_COLLECTION_ENTRY pointers into

+                                   Collection remain valid.

+**/

+RETURN_STATUS

+EFIAPI

+OrderedCollectionInsert (

+  IN OUT ORDERED_COLLECTION       *Collection,

+  OUT    ORDERED_COLLECTION_ENTRY **Entry      OPTIONAL,

+  IN     VOID                     *UserStruct

+  );

+

+

+/**

+  Delete an entry from the collection, unlinking the associated user structure.

+

+  Read-write operation.

+

+  @param[in,out] Collection  The collection to delete Entry from.

+

+  @param[in]     Entry       The collection entry to delete from Collection.

+                             The caller is responsible for ensuring that Entry

+                             belongs to Collection, and that Entry is non-NULL

+                             and valid. Entry is typically an earlier return

+                             value, or output parameter, of:

+

+                             - OrderedCollectionFind(), for deleting an entry

+                               by user structure key,

+

+                             - OrderedCollectionMin() / OrderedCollectionMax(),

+                               for deleting the minimum / maximum entry,

+

+                             - OrderedCollectionNext() /

+                               OrderedCollectionPrev(), for deleting an entry

+                               found during an iteration,

+

+                             - OrderedCollectionInsert() with return value

+                               RETURN_ALREADY_STARTED, for deleting an entry

+                               whose linked user structure caused collision

+                               during insertion.

+

+                             Existing ORDERED_COLLECTION_ENTRY pointers (ie.

+                             iterators) *different* from Entry remain valid.

+                             For example:

+

+                             - OrderedCollectionNext() /

+                               OrderedCollectionPrev() iterations in the caller

+                               can be continued from Entry, if

+                               OrderedCollectionNext() or

+                               OrderedCollectionPrev() is called on Entry

+                               *before* OrderedCollectionDelete() is. That is,

+                               fetch the successor / predecessor entry first,

+                               then delete Entry.

+

+                             - On-going iterations in the caller that would

+                               have otherwise returned Entry at some point, as

+                               dictated by user structure order, will correctly

+                               reflect the absence of Entry after

+                               OrderedCollectionDelete() is called

+                               mid-iteration.

+

+  @param[out]    UserStruct  If the caller provides this optional output-only

+                             parameter, then on output it is set to the user

+                             structure originally linked by Entry (which is now

+                             freed).

+

+                             This is a convenience that may save the caller a

+                             OrderedCollectionUserStruct() invocation before

+                             calling OrderedCollectionDelete(), in order to

+                             retrieve the user structure being unlinked.

+**/

+VOID

+EFIAPI

+OrderedCollectionDelete (

+  IN OUT ORDERED_COLLECTION       *Collection,

+  IN     ORDERED_COLLECTION_ENTRY *Entry,

+  OUT    VOID                     **UserStruct OPTIONAL

+  );

+

+#endif

diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 4daf3e6a75..bd5ce07269 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -100,6 +100,9 @@
   ##

   PrintLib|Include/Library/PrintLib.h

 

+  ##  @libraryclass  Provides an ordered collection data structure.

+  OrderedCollectionLib|Include/Library/OrderedCollectionLib.h

+

   ##  @libraryclass  Provides services to send progress/error codes to a POST card.

   PostCodeLib|Include/Library/PostCodeLib.h

 

@@ -1387,6 +1390,12 @@
   #  SwapListEntries()

   gEfiMdePkgTokenSpaceGuid.PcdVerifyNodeInList|FALSE|BOOLEAN|0x00000028

 

+  ## If TRUE, OrderedCollectionLib is instructed to validate the

+  #  ORDERED_COLLECTION structure at the end of such operations (typically

+  #  structure modifications) that justify validation of the structure for unit

+  #  testing purposes.

+  gEfiMdePkgTokenSpaceGuid.PcdValidateOrderedCollection|FALSE|BOOLEAN|0x0000002a

+

 [PcdsFixedAtBuild]

   ## Indicates the maximum length of unicode string

   gEfiMdePkgTokenSpaceGuid.PcdMaximumUnicodeStringLength|1000000|UINT32|0x00000001