1 /* 2 * CDDL HEADER START 3 * 4 * This file and its contents are supplied under the terms of the 5 * Common Development and Distribution License ("CDDL"), version 1.0. 6 * You may only use this file in accordance with the terms of version 7 * 1.0 of the CDDL. 8 * 9 * A full copy of the text of the CDDL should have accompanied this 10 * source. A copy of the CDDL is also available via the Internet at 11 * http://www.illumos.org/license/CDDL. 12 * 13 * CDDL HEADER END 14 */ 15 16 /* 17 * Copyright (c) 2012 by Delphix. All rights reserved. 18 */ 19 20 #include <dtrace.h> 21 #include <dt_impl.h> 22 #include <dt_pq.h> 23 #include <assert.h> 24 25 /* 26 * Create a new priority queue. 27 * 28 * size is the maximum number of items that will be stored in the priority 29 * queue at one time. 30 */ 31 dt_pq_t * 32 dt_pq_init(dtrace_hdl_t *dtp, uint_t size, dt_pq_value_f value_cb, void *cb_arg) 33 { 34 dt_pq_t *p; 35 assert(size > 1); 36 37 if ((p = dt_zalloc(dtp, sizeof (dt_pq_t))) == NULL) 38 return (NULL); 39 40 p->dtpq_items = dt_zalloc(dtp, size * sizeof (p->dtpq_items[0])); 41 if (p->dtpq_items == NULL) { 42 dt_free(dtp, p); 43 return (NULL); 44 } 45 46 p->dtpq_hdl = dtp; 47 p->dtpq_size = size; 48 p->dtpq_last = 1; 49 p->dtpq_value = value_cb; 50 p->dtpq_arg = cb_arg; 51 52 return (p); 53 } 54 55 void 56 dt_pq_fini(dt_pq_t *p) 57 { 58 dtrace_hdl_t *dtp = p->dtpq_hdl; 59 60 dt_free(dtp, p->dtpq_items); 61 dt_free(dtp, p); 62 } 63 64 static uint64_t 65 dt_pq_getvalue(dt_pq_t *p, uint_t index) 66 { 67 void *item = p->dtpq_items[index]; 68 return (p->dtpq_value(item, p->dtpq_arg)); 69 } 70 71 void 72 dt_pq_insert(dt_pq_t *p, void *item) 73 { 74 uint_t i; 75 76 assert(p->dtpq_last < p->dtpq_size); 77 78 i = p->dtpq_last++; 79 p->dtpq_items[i] = item; 80 81 while (i > 1 && dt_pq_getvalue(p, i) < dt_pq_getvalue(p, i / 2)) { 82 void *tmp = p->dtpq_items[i]; 83 p->dtpq_items[i] = p->dtpq_items[i / 2]; 84 p->dtpq_items[i / 2] = tmp; 85 i /= 2; 86 } 87 } 88 89 /* 90 * Return elements from the priority queue. *cookie should be zero when first 91 * called. Returns NULL when there are no more elements. 92 */ 93 void * 94 dt_pq_walk(dt_pq_t *p, uint_t *cookie) 95 { 96 (*cookie)++; 97 if (*cookie >= p->dtpq_last) 98 return (NULL); 99 100 return (p->dtpq_items[*cookie]); 101 } 102 103 void * 104 dt_pq_pop(dt_pq_t *p) 105 { 106 uint_t i = 1; 107 void *ret; 108 109 assert(p->dtpq_last > 0); 110 111 if (p->dtpq_last == 1) 112 return (NULL); 113 114 ret = p->dtpq_items[1]; 115 116 p->dtpq_last--; 117 p->dtpq_items[1] = p->dtpq_items[p->dtpq_last]; 118 p->dtpq_items[p->dtpq_last] = NULL; 119 120 for (;;) { 121 uint_t lc = i * 2; 122 uint_t rc = i * 2 + 1; 123 uint_t c; 124 uint64_t v; 125 void *tmp; 126 127 if (lc >= p->dtpq_last) 128 break; 129 130 if (rc >= p->dtpq_last) { 131 c = lc; 132 v = dt_pq_getvalue(p, lc); 133 } else { 134 uint64_t lv = dt_pq_getvalue(p, lc); 135 uint64_t rv = dt_pq_getvalue(p, rc); 136 137 if (lv < rv) { 138 c = lc; 139 v = lv; 140 } else { 141 c = rc; 142 v = rv; 143 } 144 } 145 146 if (v >= dt_pq_getvalue(p, i)) 147 break; 148 149 tmp = p->dtpq_items[i]; 150 p->dtpq_items[i] = p->dtpq_items[c]; 151 p->dtpq_items[c] = tmp; 152 153 i = c; 154 } 155 156 return (ret); 157 } 158