From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dedi548.your-server.de (dedi548.your-server.de [85.10.215.148]) by sourceware.org (Postfix) with ESMTPS id 20F00385840B for ; Tue, 5 Oct 2021 15:33:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 20F00385840B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=embedded-brains.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=embedded-brains.de Received: from sslproxy03.your-server.de ([88.198.220.132]) by dedi548.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1mXmRx-000Dk5-E4; Tue, 05 Oct 2021 17:33:49 +0200 Received: from [82.100.198.138] (helo=mail.embedded-brains.de) by sslproxy03.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mXmRx-000MSo-AS; Tue, 05 Oct 2021 17:33:49 +0200 Received: from localhost (localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id 0DB9048009C; Tue, 5 Oct 2021 17:33:49 +0200 (CEST) Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id ySyO1q5Hecz2; Tue, 5 Oct 2021 17:33:48 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id 9F4F74800FC; Tue, 5 Oct 2021 17:33:48 +0200 (CEST) X-Virus-Scanned: amavisd-new at zimbra.eb.localhost Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 45qYz2Fi7eYn; Tue, 5 Oct 2021 17:33:48 +0200 (CEST) Received: from zimbra.eb.localhost (unknown [192.168.96.242]) by mail.embedded-brains.de (Postfix) with ESMTPSA id 7C219480091; Tue, 5 Oct 2021 17:33:48 +0200 (CEST) From: Sebastian Huber To: newlib@sourceware.org Cc: devel@rtems.org Subject: [PATCH v2 4/4] sys/tree.h: Red child with black sibling rotations Date: Tue, 5 Oct 2021 17:33:44 +0200 Message-Id: <20211005153344.91266-6-sebastian.huber@embedded-brains.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20211005153344.91266-1-sebastian.huber@embedded-brains.de> References: <20211005153344.91266-1-sebastian.huber@embedded-brains.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Authenticated-Sender: smtp-embedded@poldinet.de X-Virus-Scanned: Clear (ClamAV 0.103.3/26313/Tue Oct 5 11:04:18 2021) X-Spam-Status: No, score=-11.2 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Oct 2021 15:33:52 -0000 Add specialized rotations RB_RED_ROTATE_LEFT() and RB_RED_ROTATE_RIGHT() = which may be used if we rotate a red child which has a black sibling. Such a r= ed node must have at least two child nodes so that the following red-black t= ree invariant is fulfilled: Every path from a given node to any of its descendant NULL nodes goes t= hrough the same number of black nodes. PARENT / \ BLACK RED / \ BLACK BLACK --- newlib/libc/include/sys/tree.h | 43 ++++++++++++++++++++++++++++++++-- 1 file changed, 41 insertions(+), 2 deletions(-) diff --git a/newlib/libc/include/sys/tree.h b/newlib/libc/include/sys/tre= e.h index f6190f7f4..7a3b55bdf 100644 --- a/newlib/libc/include/sys/tree.h +++ b/newlib/libc/include/sys/tree.h @@ -412,6 +412,45 @@ struct { \ RB_AUGMENT(right); \ } while (/*CONSTCOND*/ 0) =20 +/* + * The RB_RED_ROTATE_LEFT() and RB_RED_ROTATE_RIGHT() rotations are spec= ialized + * versions of RB_ROTATE_LEFT() and RB_ROTATE_RIGHT() which may be used = if we + * rotate a red child element which has a black sibling. Such a red nod= e must + * have at least two child nodes so that the following red-black tree in= variant + * is fulfilled: + * + * Every path from a given node to any of its descendant NULL nodes goe= s + * through the same number of black nodes. + * + * parent + * / \ + * BLACK RED (elm) + * / \ + * BLACK BLACK + */ + +#define RB_RED_ROTATE_LEFT(head, elm, tmp, field) do { \ + (tmp) =3D RB_RIGHT(elm, field); \ + RB_RIGHT(elm, field) =3D RB_LEFT(tmp, field); \ + RB_SET_PARENT(RB_RIGHT(elm, field), elm, field); \ + RB_SET_PARENT(tmp, RB_PARENT(elm, field), field); \ + RB_SWAP_CHILD(head, elm, tmp, field); \ + RB_LEFT(tmp, field) =3D (elm); \ + RB_SET_PARENT(elm, tmp, field); \ + RB_AUGMENT(elm); \ +} while (/*CONSTCOND*/ 0) + +#define RB_RED_ROTATE_RIGHT(head, elm, tmp, field) do { \ + (tmp) =3D RB_LEFT(elm, field); \ + RB_LEFT(elm, field) =3D RB_RIGHT(tmp, field); \ + RB_SET_PARENT(RB_LEFT(elm, field), elm, field); \ + RB_SET_PARENT(tmp, RB_PARENT(elm, field), field); \ + RB_SWAP_CHILD(head, elm, tmp, field); \ + RB_RIGHT(tmp, field) =3D (elm); \ + RB_SET_PARENT(elm, tmp, field); \ + RB_AUGMENT(elm); \ +} while (/*CONSTCOND*/ 0) + /* Generates prototypes and inline functions */ #define RB_PROTOTYPE(name, type, field, cmp) \ RB_PROTOTYPE_INTERNAL(name, type, field, cmp,) @@ -526,7 +565,7 @@ name##_RB_REMOVE_COLOR(struct name *head, struct type= *parent) \ tmp =3D RB_RIGHT(parent, field); \ if (RB_COLOR(tmp, field) =3D=3D RB_RED) { \ RB_SET_BLACKRED(tmp, parent, field); \ - RB_ROTATE_LEFT(head, parent, tmp, field);\ + RB_RED_ROTATE_LEFT(head, parent, tmp, field); \ tmp =3D RB_RIGHT(parent, field); \ } \ if (RB_ISRED(RB_RIGHT(tmp, field), field)) \ @@ -552,7 +591,7 @@ name##_RB_REMOVE_COLOR(struct name *head, struct type= *parent) \ tmp =3D RB_LEFT(parent, field); \ if (RB_COLOR(tmp, field) =3D=3D RB_RED) { \ RB_SET_BLACKRED(tmp, parent, field); \ - RB_ROTATE_RIGHT(head, parent, tmp, field);\ + RB_RED_ROTATE_RIGHT(head, parent, tmp, field); \ tmp =3D RB_LEFT(parent, field); \ } \ if (RB_ISRED(RB_LEFT(tmp, field), field)) \ --=20 2.26.2