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      1 /*
      2  * Copyright 2005-2020 The OpenSSL Project Authors. All Rights Reserved.
      3  *
      4  * Licensed under the Apache License 2.0 (the "License").  You may not use
      5  * this file except in compliance with the License.  You can obtain a copy
      6  * in the file LICENSE in the source distribution or at
      7  * https://www.openssl.org/source/license.html
      8  */
      9 
     10 #include "ssl_local.h"
     11 #include <openssl/bn.h>
     12 
     13 struct pqueue_st {
     14     pitem *items;
     15     int count;
     16 };
     17 
     18 pitem *pitem_new(unsigned char *prio64be, void *data)
     19 {
     20     pitem *item = OPENSSL_malloc(sizeof(*item));
     21 
     22     if (item == NULL)
     23         return NULL;
     24 
     25     memcpy(item->priority, prio64be, sizeof(item->priority));
     26     item->data = data;
     27     item->next = NULL;
     28     return item;
     29 }
     30 
     31 void pitem_free(pitem *item)
     32 {
     33     OPENSSL_free(item);
     34 }
     35 
     36 pqueue *pqueue_new(void)
     37 {
     38     pqueue *pq = OPENSSL_zalloc(sizeof(*pq));
     39 
     40     return pq;
     41 }
     42 
     43 void pqueue_free(pqueue *pq)
     44 {
     45     OPENSSL_free(pq);
     46 }
     47 
     48 pitem *pqueue_insert(pqueue *pq, pitem *item)
     49 {
     50     pitem *curr, *next;
     51 
     52     if (pq->items == NULL) {
     53         pq->items = item;
     54         return item;
     55     }
     56 
     57     for (curr = NULL, next = pq->items;
     58         next != NULL; curr = next, next = next->next) {
     59         /*
     60          * we can compare 64-bit value in big-endian encoding with memcmp:-)
     61          */
     62         int cmp = memcmp(next->priority, item->priority, 8);
     63         if (cmp > 0) { /* next > item */
     64             item->next = next;
     65 
     66             if (curr == NULL)
     67                 pq->items = item;
     68             else
     69                 curr->next = item;
     70 
     71             return item;
     72         }
     73 
     74         else if (cmp == 0) /* duplicates not allowed */
     75             return NULL;
     76     }
     77 
     78     item->next = NULL;
     79     curr->next = item;
     80 
     81     return item;
     82 }
     83 
     84 pitem *pqueue_peek(pqueue *pq)
     85 {
     86     return pq->items;
     87 }
     88 
     89 pitem *pqueue_pop(pqueue *pq)
     90 {
     91     pitem *item = pq->items;
     92 
     93     if (pq->items != NULL)
     94         pq->items = pq->items->next;
     95 
     96     return item;
     97 }
     98 
     99 pitem *pqueue_find(pqueue *pq, unsigned char *prio64be)
    100 {
    101     pitem *next;
    102     pitem *found = NULL;
    103 
    104     if (pq->items == NULL)
    105         return NULL;
    106 
    107     for (next = pq->items; next->next != NULL; next = next->next) {
    108         if (memcmp(next->priority, prio64be, 8) == 0) {
    109             found = next;
    110             break;
    111         }
    112     }
    113 
    114     /* check the one last node */
    115     if (memcmp(next->priority, prio64be, 8) == 0)
    116         found = next;
    117 
    118     if (!found)
    119         return NULL;
    120 
    121     return found;
    122 }
    123 
    124 pitem *pqueue_iterator(pqueue *pq)
    125 {
    126     return pqueue_peek(pq);
    127 }
    128 
    129 pitem *pqueue_next(piterator *item)
    130 {
    131     pitem *ret;
    132 
    133     if (item == NULL || *item == NULL)
    134         return NULL;
    135 
    136     /* *item != NULL */
    137     ret = *item;
    138     *item = (*item)->next;
    139 
    140     return ret;
    141 }
    142 
    143 size_t pqueue_size(pqueue *pq)
    144 {
    145     pitem *item = pq->items;
    146     size_t count = 0;
    147 
    148     while (item != NULL) {
    149         count++;
    150         item = item->next;
    151     }
    152     return count;
    153 }
    154