Coverage Report

Created: 2024-11-21 07:03

/src/boringssl/crypto/lhash/lhash.c
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Source (jump to first uncovered line)
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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 * All rights reserved.
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 *
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 * This package is an SSL implementation written
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 * by Eric Young (eay@cryptsoft.com).
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 * The implementation was written so as to conform with Netscapes SSL.
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 *
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 * This library is free for commercial and non-commercial use as long as
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 * the following conditions are aheared to.  The following conditions
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 * apply to all code found in this distribution, be it the RC4, RSA,
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 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
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 * included with this distribution is covered by the same copyright terms
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 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
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 *
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 * Copyright remains Eric Young's, and as such any Copyright notices in
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 * the code are not to be removed.
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 * If this package is used in a product, Eric Young should be given attribution
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 * as the author of the parts of the library used.
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 * This can be in the form of a textual message at program startup or
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 * in documentation (online or textual) provided with the package.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *    "This product includes cryptographic software written by
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 *     Eric Young (eay@cryptsoft.com)"
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 *    The word 'cryptographic' can be left out if the rouines from the library
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 *    being used are not cryptographic related :-).
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 * 4. If you include any Windows specific code (or a derivative thereof) from
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 *    the apps directory (application code) you must include an acknowledgement:
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 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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 *
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 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 * The licence and distribution terms for any publically available version or
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 * derivative of this code cannot be changed.  i.e. this code cannot simply be
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 * copied and put under another distribution licence
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 * [including the GNU Public Licence.] */
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#include <openssl/lhash.h>
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#include <assert.h>
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#include <limits.h>
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#include <string.h>
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#include <openssl/mem.h>
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#include "internal.h"
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#include "../internal.h"
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// kMinNumBuckets is the minimum size of the buckets array in an |_LHASH|.
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static const size_t kMinNumBuckets = 16;
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// kMaxAverageChainLength contains the maximum, average chain length. When the
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// average chain length exceeds this value, the hash table will be resized.
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static const size_t kMaxAverageChainLength = 2;
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static const size_t kMinAverageChainLength = 1;
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// lhash_item_st is an element of a hash chain. It points to the opaque data
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// for this element and to the next item in the chain. The linked-list is NULL
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// terminated.
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typedef struct lhash_item_st {
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  void *data;
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  struct lhash_item_st *next;
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  // hash contains the cached, hash value of |data|.
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  uint32_t hash;
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} LHASH_ITEM;
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struct lhash_st {
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  // num_items contains the total number of items in the hash table.
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  size_t num_items;
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  // buckets is an array of |num_buckets| pointers. Each points to the head of
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  // a chain of LHASH_ITEM objects that have the same hash value, mod
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  // |num_buckets|.
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  LHASH_ITEM **buckets;
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  // num_buckets contains the length of |buckets|. This value is always >=
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  // kMinNumBuckets.
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  size_t num_buckets;
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  // callback_depth contains the current depth of |lh_doall| or |lh_doall_arg|
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  // calls. If non-zero then this suppresses resizing of the |buckets| array,
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  // which would otherwise disrupt the iteration.
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  unsigned callback_depth;
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  lhash_cmp_func comp;
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  lhash_hash_func hash;
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};
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0
_LHASH *OPENSSL_lh_new(lhash_hash_func hash, lhash_cmp_func comp) {
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0
  _LHASH *ret = OPENSSL_zalloc(sizeof(_LHASH));
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0
  if (ret == NULL) {
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0
    return NULL;
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0
  }
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0
  ret->num_buckets = kMinNumBuckets;
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0
  ret->buckets = OPENSSL_calloc(ret->num_buckets, sizeof(LHASH_ITEM *));
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0
  if (ret->buckets == NULL) {
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0
    OPENSSL_free(ret);
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0
    return NULL;
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0
  }
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  ret->comp = comp;
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0
  ret->hash = hash;
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0
  return ret;
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0
}
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0
void OPENSSL_lh_free(_LHASH *lh) {
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0
  if (lh == NULL) {
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0
    return;
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0
  }
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0
  for (size_t i = 0; i < lh->num_buckets; i++) {
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0
    LHASH_ITEM *next;
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0
    for (LHASH_ITEM *n = lh->buckets[i]; n != NULL; n = next) {
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0
      next = n->next;
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      OPENSSL_free(n);
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0
    }
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0
  }
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  OPENSSL_free(lh->buckets);
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  OPENSSL_free(lh);
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0
}
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size_t OPENSSL_lh_num_items(const _LHASH *lh) { return lh->num_items; }
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// get_next_ptr_and_hash returns a pointer to the pointer that points to the
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// item equal to |data|. In other words, it searches for an item equal to |data|
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// and, if it's at the start of a chain, then it returns a pointer to an
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// element of |lh->buckets|, otherwise it returns a pointer to the |next|
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// element of the previous item in the chain. If an element equal to |data| is
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// not found, it returns a pointer that points to a NULL pointer. If |out_hash|
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// is not NULL, then it also puts the hash value of |data| in |*out_hash|.
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static LHASH_ITEM **get_next_ptr_and_hash(const _LHASH *lh, uint32_t *out_hash,
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                                          const void *data,
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                                          lhash_hash_func_helper call_hash_func,
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0
                                          lhash_cmp_func_helper call_cmp_func) {
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0
  const uint32_t hash = call_hash_func(lh->hash, data);
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0
  if (out_hash != NULL) {
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0
    *out_hash = hash;
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0
  }
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  LHASH_ITEM **ret = &lh->buckets[hash % lh->num_buckets];
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0
  for (LHASH_ITEM *cur = *ret; cur != NULL; cur = *ret) {
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0
    if (call_cmp_func(lh->comp, cur->data, data) == 0) {
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0
      break;
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0
    }
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0
    ret = &cur->next;
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0
  }
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  return ret;
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0
}
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// get_next_ptr_by_key behaves like |get_next_ptr_and_hash| but takes a key
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// which may be a different type from the values stored in |lh|.
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static LHASH_ITEM **get_next_ptr_by_key(const _LHASH *lh, const void *key,
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                                        uint32_t key_hash,
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                                        int (*cmp_key)(const void *key,
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0
                                                       const void *value)) {
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0
  LHASH_ITEM **ret = &lh->buckets[key_hash % lh->num_buckets];
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0
  for (LHASH_ITEM *cur = *ret; cur != NULL; cur = *ret) {
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0
    if (cmp_key(key, cur->data) == 0) {
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0
      break;
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0
    }
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0
    ret = &cur->next;
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0
  }
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  return ret;
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0
}
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void *OPENSSL_lh_retrieve(const _LHASH *lh, const void *data,
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                          lhash_hash_func_helper call_hash_func,
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0
                          lhash_cmp_func_helper call_cmp_func) {
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0
  LHASH_ITEM **next_ptr =
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0
      get_next_ptr_and_hash(lh, NULL, data, call_hash_func, call_cmp_func);
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0
  return *next_ptr == NULL ? NULL : (*next_ptr)->data;
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0
}
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void *OPENSSL_lh_retrieve_key(const _LHASH *lh, const void *key,
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                              uint32_t key_hash,
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                              int (*cmp_key)(const void *key,
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0
                                             const void *value)) {
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0
  LHASH_ITEM **next_ptr = get_next_ptr_by_key(lh, key, key_hash, cmp_key);
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0
  return *next_ptr == NULL ? NULL : (*next_ptr)->data;
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0
}
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// lh_rebucket allocates a new array of |new_num_buckets| pointers and
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// redistributes the existing items into it before making it |lh->buckets| and
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// freeing the old array.
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0
static void lh_rebucket(_LHASH *lh, const size_t new_num_buckets) {
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0
  LHASH_ITEM **new_buckets, *cur, *next;
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0
  size_t i, alloc_size;
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0
  alloc_size = sizeof(LHASH_ITEM *) * new_num_buckets;
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0
  if (alloc_size / sizeof(LHASH_ITEM*) != new_num_buckets) {
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0
    return;
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0
  }
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0
  new_buckets = OPENSSL_zalloc(alloc_size);
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0
  if (new_buckets == NULL) {
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0
    return;
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0
  }
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0
  for (i = 0; i < lh->num_buckets; i++) {
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0
    for (cur = lh->buckets[i]; cur != NULL; cur = next) {
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0
      const size_t new_bucket = cur->hash % new_num_buckets;
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0
      next = cur->next;
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0
      cur->next = new_buckets[new_bucket];
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0
      new_buckets[new_bucket] = cur;
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0
    }
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0
  }
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0
  OPENSSL_free(lh->buckets);
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0
  lh->num_buckets = new_num_buckets;
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0
  lh->buckets = new_buckets;
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0
}
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// lh_maybe_resize resizes the |buckets| array if needed.
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0
static void lh_maybe_resize(_LHASH *lh) {
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0
  size_t avg_chain_length;
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0
  if (lh->callback_depth > 0) {
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    // Don't resize the hash if we are currently iterating over it.
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0
    return;
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0
  }
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0
  assert(lh->num_buckets >= kMinNumBuckets);
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0
  avg_chain_length = lh->num_items / lh->num_buckets;
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0
  if (avg_chain_length > kMaxAverageChainLength) {
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0
    const size_t new_num_buckets = lh->num_buckets * 2;
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0
    if (new_num_buckets > lh->num_buckets) {
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0
      lh_rebucket(lh, new_num_buckets);
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0
    }
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0
  } else if (avg_chain_length < kMinAverageChainLength &&
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0
             lh->num_buckets > kMinNumBuckets) {
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0
    size_t new_num_buckets = lh->num_buckets / 2;
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0
    if (new_num_buckets < kMinNumBuckets) {
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0
      new_num_buckets = kMinNumBuckets;
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0
    }
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0
    lh_rebucket(lh, new_num_buckets);
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0
  }
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0
}
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int OPENSSL_lh_insert(_LHASH *lh, void **old_data, void *data,
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                      lhash_hash_func_helper call_hash_func,
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0
                      lhash_cmp_func_helper call_cmp_func) {
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0
  uint32_t hash;
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0
  LHASH_ITEM **next_ptr, *item;
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0
  *old_data = NULL;
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0
  next_ptr =
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0
      get_next_ptr_and_hash(lh, &hash, data, call_hash_func, call_cmp_func);
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0
  if (*next_ptr != NULL) {
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    // An element equal to |data| already exists in the hash table. It will be
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    // replaced.
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0
    *old_data = (*next_ptr)->data;
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0
    (*next_ptr)->data = data;
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0
    return 1;
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0
  }
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  // An element equal to |data| doesn't exist in the hash table yet.
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0
  item = OPENSSL_malloc(sizeof(LHASH_ITEM));
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0
  if (item == NULL) {
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0
    return 0;
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0
  }
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0
  item->data = data;
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0
  item->hash = hash;
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0
  item->next = NULL;
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0
  *next_ptr = item;
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0
  lh->num_items++;
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0
  lh_maybe_resize(lh);
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0
  return 1;
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0
}
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void *OPENSSL_lh_delete(_LHASH *lh, const void *data,
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                        lhash_hash_func_helper call_hash_func,
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0
                        lhash_cmp_func_helper call_cmp_func) {
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0
  LHASH_ITEM **next_ptr, *item, *ret;
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305
0
  next_ptr =
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0
      get_next_ptr_and_hash(lh, NULL, data, call_hash_func, call_cmp_func);
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308
0
  if (*next_ptr == NULL) {
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    // No such element.
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0
    return NULL;
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0
  }
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0
  item = *next_ptr;
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0
  *next_ptr = item->next;
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0
  ret = item->data;
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0
  OPENSSL_free(item);
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0
  lh->num_items--;
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0
  lh_maybe_resize(lh);
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0
  return ret;
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0
}
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0
void OPENSSL_lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), void *arg) {
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0
  if (lh == NULL) {
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0
    return;
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0
  }
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329
0
  if (lh->callback_depth < UINT_MAX) {
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    // |callback_depth| is a saturating counter.
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0
    lh->callback_depth++;
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0
  }
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334
0
  for (size_t i = 0; i < lh->num_buckets; i++) {
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0
    LHASH_ITEM *next;
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0
    for (LHASH_ITEM *cur = lh->buckets[i]; cur != NULL; cur = next) {
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0
      next = cur->next;
338
0
      func(cur->data, arg);
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0
    }
340
0
  }
341
342
0
  if (lh->callback_depth < UINT_MAX) {
343
0
    lh->callback_depth--;
344
0
  }
345
346
  // The callback may have added or removed elements and the non-zero value of
347
  // |callback_depth| will have suppressed any resizing. Thus any needed
348
  // resizing is done here.
349
0
  lh_maybe_resize(lh);
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0
}