1 /****************************************************************************** 2 * 3 * Copyright (C) 2002 Jason Evans <jasone (at) canonware.com>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice(s), this list of conditions and the following disclaimer 11 * unmodified other than the allowable addition of one or more 12 * copyright notices. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice(s), this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 25 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 27 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 28 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 ******************************************************************************/ 31 32 /* Ring definitions. */ 33 #define qr(a_type) \ 34 struct { \ 35 a_type *qre_next; \ 36 a_type *qre_prev; \ 37 } 38 39 /* Ring functions. */ 40 #define qr_new(a_qr, a_field) do { \ 41 (a_qr)->a_field.qre_next = (a_qr); \ 42 (a_qr)->a_field.qre_prev = (a_qr); \ 43 } while (0) 44 45 #define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next) 46 47 #define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev) 48 49 #define qr_before_insert(a_qrelm, a_qr, a_field) do { \ 50 (a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev; \ 51 (a_qr)->a_field.qre_next = (a_qrelm); \ 52 (a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr); \ 53 (a_qrelm)->a_field.qre_prev = (a_qr); \ 54 } while (0) 55 56 #define qr_after_insert(a_qrelm, a_qr, a_field) \ 57 do \ 58 { \ 59 (a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next; \ 60 (a_qr)->a_field.qre_prev = (a_qrelm); \ 61 (a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr); \ 62 (a_qrelm)->a_field.qre_next = (a_qr); \ 63 } while (0) 64 65 #define qr_meld(a_qr_a, a_qr_b, a_field) do { \ 66 void *t; \ 67 (a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b); \ 68 (a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a); \ 69 t = (a_qr_a)->a_field.qre_prev; \ 70 (a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev; \ 71 (a_qr_b)->a_field.qre_prev = t; \ 72 } while (0) 73 74 /* qr_meld() and qr_split() are functionally equivalent, so there's no need to 75 * have two copies of the code. */ 76 #define qr_split(a_qr_a, a_qr_b, a_field) \ 77 qr_meld((a_qr_a), (a_qr_b), a_field) 78 79 #define qr_remove(a_qr, a_field) do { \ 80 (a_qr)->a_field.qre_prev->a_field.qre_next \ 81 = (a_qr)->a_field.qre_next; \ 82 (a_qr)->a_field.qre_next->a_field.qre_prev \ 83 = (a_qr)->a_field.qre_prev; \ 84 (a_qr)->a_field.qre_next = (a_qr); \ 85 (a_qr)->a_field.qre_prev = (a_qr); \ 86 } while (0) 87 88 #define qr_foreach(var, a_qr, a_field) \ 89 for ((var) = (a_qr); \ 90 (var) != NULL; \ 91 (var) = (((var)->a_field.qre_next != (a_qr)) \ 92 ? (var)->a_field.qre_next : NULL)) 93 94 #define qr_reverse_foreach(var, a_qr, a_field) \ 95 for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL; \ 96 (var) != NULL; \ 97 (var) = (((var) != (a_qr)) \ 98 ? (var)->a_field.qre_prev : NULL)) 99
