1 /****************************************************************************** 2 * 3 * Copyright (C) 2002 Jason Evans <jasone@FreeBSD.org>. 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 #ifndef QR_H_ 33 #define QR_H_ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD: stable/9/lib/libc/stdlib/qr.h 203329 2010-01-31 23:16:10Z jasone $"); 37 38 /* Ring definitions. */ 39 #define qr(a_type) \ 40 struct { \ 41 a_type *qre_next; \ 42 a_type *qre_prev; \ 43 } 44 45 /* Ring functions. */ 46 #define qr_new(a_qr, a_field) do { \ 47 (a_qr)->a_field.qre_next = (a_qr); \ 48 (a_qr)->a_field.qre_prev = (a_qr); \ 49 } while (0) 50 51 #define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next) 52 53 #define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev) 54 55 #define qr_before_insert(a_qrelm, a_qr, a_field) do { \ 56 (a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev; \ 57 (a_qr)->a_field.qre_next = (a_qrelm); \ 58 (a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr); \ 59 (a_qrelm)->a_field.qre_prev = (a_qr); \ 60 } while (0) 61 62 #define qr_after_insert(a_qrelm, a_qr, a_field) \ 63 do \ 64 { \ 65 (a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next; \ 66 (a_qr)->a_field.qre_prev = (a_qrelm); \ 67 (a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr); \ 68 (a_qrelm)->a_field.qre_next = (a_qr); \ 69 } while (0) 70 71 #define qr_meld(a_qr_a, a_qr_b, a_field) do { \ 72 void *t; \ 73 (a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b); \ 74 (a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a); \ 75 t = (a_qr_a)->a_field.qre_prev; \ 76 (a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev; \ 77 (a_qr_b)->a_field.qre_prev = t; \ 78 } while (0) 79 80 /* qr_meld() and qr_split() are functionally equivalent, so there's no need to 81 * have two copies of the code. */ 82 #define qr_split(a_qr_a, a_qr_b, a_field) \ 83 qr_meld((a_qr_a), (a_qr_b), a_field) 84 85 #define qr_remove(a_qr, a_field) do { \ 86 (a_qr)->a_field.qre_prev->a_field.qre_next \ 87 = (a_qr)->a_field.qre_next; \ 88 (a_qr)->a_field.qre_next->a_field.qre_prev \ 89 = (a_qr)->a_field.qre_prev; \ 90 (a_qr)->a_field.qre_next = (a_qr); \ 91 (a_qr)->a_field.qre_prev = (a_qr); \ 92 } while (0) 93 94 #define qr_foreach(var, a_qr, a_field) \ 95 for ((var) = (a_qr); \ 96 (var) != NULL; \ 97 (var) = (((var)->a_field.qre_next != (a_qr)) \ 98 ? (var)->a_field.qre_next : NULL)) 99 100 #define qr_reverse_foreach(var, a_qr, a_field) \ 101 for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL; \ 102 (var) != NULL; \ 103 (var) = (((var) != (a_qr)) \ 104 ? (var)->a_field.qre_prev : NULL)) 105 106 #endif /* QR_H_ */ 107