+/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
+ * Junior University
+ *
+ * We are making the OpenFlow specification and associated documentation
+ * (Software) available for public use and benefit with the expectation
+ * that others will use, modify and enhance the Software and contribute
+ * those enhancements back to the community. However, since we would
+ * like to make the Software available for broadest use, with as few
+ * restrictions as possible permission is hereby granted, free of
+ * charge, to any person obtaining a copy of this Software to deal in
+ * the Software under the copyrights without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * The name and trademarks of copyright holder(s) may NOT be used in
+ * advertising or publicity pertaining to the Software or any
+ * derivatives without specific, written prior permission.
+ */
+
+#include <config.h>
+#include "port-array.h"
+
+static struct port_array_l2 l2_sentinel;
+static struct port_array_l3 l3_sentinel;
+static bool inited;
+
+/* Initializes 'pa' as an empty port_array. */
+void
+port_array_init(struct port_array *pa)
+{
+ size_t i;
+ if (!inited) {
+ inited = true;
+ for (i = 0; i < PORT_ARRAY_L2_SIZE; i++) {
+ l2_sentinel.l2[i] = &l3_sentinel;
+ }
+ }
+ for (i = 0; i < PORT_ARRAY_L1_SIZE; i++) {
+ pa->l1[i] = &l2_sentinel;
+ }
+}
+
+/* Sets 'pa' element numbered 'idx' to 'p'. */
+void
+port_array_set(struct port_array *pa, uint16_t idx, void *p)
+{
+ struct port_array_l2 **l2p, *l2;
+ struct port_array_l3 **l3p, *l3;
+
+ /* Traverse level 1. */
+ l2p = &pa->l1[PORT_ARRAY_L1(idx)];
+ if (*l2p == &l2_sentinel) {
+ *l2p = xmemdup(&l2_sentinel, sizeof l2_sentinel);
+ }
+ l2 = *l2p;
+
+ /* Traverse level 2. */
+ l3p = &l2->l2[PORT_ARRAY_L2(idx)];
+ if (*l3p == &l3_sentinel) {
+ *l3p = xmemdup(&l3_sentinel, sizeof l3_sentinel);
+ }
+ l3 = *l3p;
+
+ /* Set level 3. */
+ l3->l3[PORT_ARRAY_L3(idx)] = p;
+}
+
+static void *
+next(const struct port_array *pa, unsigned int *idxp)
+{
+ unsigned int idx = *idxp;
+
+ /* Using shift-right directly here, instead of PORT_ARRAY_L1(idx), ensures
+ * that with an initially too-big value of '*idxp' we will skip the outer
+ * loop and return NULL. */
+ unsigned int l1_idx = idx >> PORT_ARRAY_L1_SHIFT;
+ unsigned int l2_idx = PORT_ARRAY_L2(idx);
+ unsigned int l3_idx = PORT_ARRAY_L3(idx);
+ while (l1_idx < PORT_ARRAY_L1_SIZE) {
+ struct port_array_l2 *l2 = pa->l1[l1_idx];
+ if (l2 != &l2_sentinel) {
+ while (l2_idx < PORT_ARRAY_L2_SIZE) {
+ struct port_array_l3 *l3 = l2->l2[l2_idx];
+ if (l3 != &l3_sentinel) {
+ while (l3_idx < PORT_ARRAY_L3_SIZE) {
+ void *p = l3->l3[l3_idx];
+ if (p) {
+ *idxp = ((l1_idx << PORT_ARRAY_L1_SHIFT)
+ | (l2_idx << PORT_ARRAY_L2_SHIFT)
+ | (l3_idx << PORT_ARRAY_L3_SHIFT));
+ return p;
+ }
+ l3_idx++;
+ }
+ }
+ l2_idx++;
+ l3_idx = 0;
+ }
+ }
+ l1_idx++;
+ l2_idx = 0;
+ l3_idx = 0;
+ }
+ *idxp = PORT_ARRAY_SIZE;
+ return NULL;
+}
+
+/* Returns the value of the lowest-numbered non-empty element of 'pa', and sets
+ * '*idxp' to that element's index. If 'pa' is entirely empty, returns a null
+ * pointer and sets '*idxp' to 65536. */
+void *
+port_array_first(const struct port_array *pa, unsigned int *idxp)
+{
+ *idxp = 0;
+ return next(pa, idxp);
+}
+
+/* Returns the value of the lowest-numbered non-empty element of 'pa' greater
+ * than the initial value of '*idxp', and sets '*idxp' to that element's index.
+ * If 'pa' contains no non-empty elements with indexes greater than the initial
+ * value of '*idxp', returns a null pointer and sets '*idxp' to 65536. */
+void *
+port_array_next(const struct port_array *pa, unsigned int *idxp)
+{
+ ++*idxp;
+ return next(pa, idxp);
+}