Provided by: libczmq-dev_4.2.1-2build1_amd64 bug

NAME

       zhashx - Class for extended generic hash container

SYNOPSIS

       //  This is a stable class, and may not change except for emergencies. It
       //  is provided in stable builds.
       //  This class has draft methods, which may change over time. They are not
       //  in stable releases, by default. Use --enable-drafts to enable.
       // Destroy an item
       typedef void (zhashx_destructor_fn) (
           void **item);

       // Duplicate an item
       typedef void * (zhashx_duplicator_fn) (
           const void *item);

       // Compare two items, for sorting
       typedef int (zhashx_comparator_fn) (
           const void *item1, const void *item2);

       // Destroy an item.
       typedef void (zhashx_free_fn) (
           void *data);

       // Hash function for keys.
       typedef size_t (zhashx_hash_fn) (
           const void *key);

       // Serializes an item to a longstr.
       // The caller takes ownership of the newly created object.
       typedef char * (zhashx_serializer_fn) (
           const void *item);

       // Deserializes a longstr into an item.
       // The caller takes ownership of the newly created object.
       typedef void * (zhashx_deserializer_fn) (
           const char *item_str);

       //  Create a new, empty hash container
       CZMQ_EXPORT zhashx_t *
           zhashx_new (void);

       //  Unpack binary frame into a new hash table. Packed data must follow format
       //  defined by zhashx_pack. Hash table is set to autofree. An empty frame
       //  unpacks to an empty hash table.
       CZMQ_EXPORT zhashx_t *
           zhashx_unpack (zframe_t *frame);

       //  Destroy a hash container and all items in it
       CZMQ_EXPORT void
           zhashx_destroy (zhashx_t **self_p);

       //  Insert item into hash table with specified key and item.
       //  If key is already present returns -1 and leaves existing item unchanged
       //  Returns 0 on success.
       CZMQ_EXPORT int
           zhashx_insert (zhashx_t *self, const void *key, void *item);

       //  Update or insert item into hash table with specified key and item. If the
       //  key is already present, destroys old item and inserts new one. If you set
       //  a container item destructor, this is called on the old value. If the key
       //  was not already present, inserts a new item. Sets the hash cursor to the
       //  new item.
       CZMQ_EXPORT void
           zhashx_update (zhashx_t *self, const void *key, void *item);

       //  Remove an item specified by key from the hash table. If there was no such
       //  item, this function does nothing.
       CZMQ_EXPORT void
           zhashx_delete (zhashx_t *self, const void *key);

       //  Delete all items from the hash table. If the key destructor is
       //  set, calls it on every key. If the item destructor is set, calls
       //  it on every item.
       CZMQ_EXPORT void
           zhashx_purge (zhashx_t *self);

       //  Return the item at the specified key, or null
       CZMQ_EXPORT void *
           zhashx_lookup (zhashx_t *self, const void *key);

       //  Reindexes an item from an old key to a new key. If there was no such
       //  item, does nothing. Returns 0 if successful, else -1.
       CZMQ_EXPORT int
           zhashx_rename (zhashx_t *self, const void *old_key, const void *new_key);

       //  Set a free function for the specified hash table item. When the item is
       //  destroyed, the free function, if any, is called on that item.
       //  Use this when hash items are dynamically allocated, to ensure that
       //  you don't have memory leaks. You can pass 'free' or NULL as a free_fn.
       //  Returns the item, or NULL if there is no such item.
       CZMQ_EXPORT void *
           zhashx_freefn (zhashx_t *self, const void *key, zhashx_free_fn free_fn);

       //  Return the number of keys/items in the hash table
       CZMQ_EXPORT size_t
           zhashx_size (zhashx_t *self);

       //  Return a zlistx_t containing the keys for the items in the
       //  table. Uses the key_duplicator to duplicate all keys and sets the
       //  key_destructor as destructor for the list.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT zlistx_t *
           zhashx_keys (zhashx_t *self);

       //  Return a zlistx_t containing the values for the items in the
       //  table. Uses the duplicator to duplicate all items and sets the
       //  destructor as destructor for the list.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT zlistx_t *
           zhashx_values (zhashx_t *self);

       //  Simple iterator; returns first item in hash table, in no given order,
       //  or NULL if the table is empty. This method is simpler to use than the
       //  foreach() method, which is deprecated. To access the key for this item
       //  use zhashx_cursor(). NOTE: do NOT modify the table while iterating.
       CZMQ_EXPORT void *
           zhashx_first (zhashx_t *self);

       //  Simple iterator; returns next item in hash table, in no given order,
       //  or NULL if the last item was already returned. Use this together with
       //  zhashx_first() to process all items in a hash table. If you need the
       //  items in sorted order, use zhashx_keys() and then zlistx_sort(). To
       //  access the key for this item use zhashx_cursor(). NOTE: do NOT modify
       //  the table while iterating.
       CZMQ_EXPORT void *
           zhashx_next (zhashx_t *self);

       //  After a successful first/next method, returns the key for the item that
       //  was returned. This is a constant string that you may not modify or
       //  deallocate, and which lasts as long as the item in the hash. After an
       //  unsuccessful first/next, returns NULL.
       CZMQ_EXPORT const void *
           zhashx_cursor (zhashx_t *self);

       //  Add a comment to hash table before saving to disk. You can add as many
       //  comment lines as you like. These comment lines are discarded when loading
       //  the file. If you use a null format, all comments are deleted.
       CZMQ_EXPORT void
           zhashx_comment (zhashx_t *self, const char *format, ...) CHECK_PRINTF (2);

       //  Save hash table to a text file in name=value format. Hash values must be
       //  printable strings; keys may not contain '=' character. Returns 0 if OK,
       //  else -1 if a file error occurred.
       CZMQ_EXPORT int
           zhashx_save (zhashx_t *self, const char *filename);

       //  Load hash table from a text file in name=value format; hash table must
       //  already exist. Hash values must printable strings; keys may not contain
       //  '=' character. Returns 0 if OK, else -1 if a file was not readable.
       CZMQ_EXPORT int
           zhashx_load (zhashx_t *self, const char *filename);

       //  When a hash table was loaded from a file by zhashx_load, this method will
       //  reload the file if it has been modified since, and is "stable", i.e. not
       //  still changing. Returns 0 if OK, -1 if there was an error reloading the
       //  file.
       CZMQ_EXPORT int
           zhashx_refresh (zhashx_t *self);

       //  Serialize hash table to a binary frame that can be sent in a message.
       //  The packed format is compatible with the 'dictionary' type defined in
       //  http://rfc.zeromq.org/spec:35/FILEMQ, and implemented by zproto:
       //
       //     ; A list of name/value pairs
       //     dictionary      = dict-count *( dict-name dict-value )
       //     dict-count      = number-4
       //     dict-value      = longstr
       //     dict-name       = string
       //
       //     ; Strings are always length + text contents
       //     longstr         = number-4 *VCHAR
       //     string          = number-1 *VCHAR
       //
       //     ; Numbers are unsigned integers in network byte order
       //     number-1        = 1OCTET
       //     number-4        = 4OCTET
       //
       //  Comments are not included in the packed data. Item values MUST be
       //  strings.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT zframe_t *
           zhashx_pack (zhashx_t *self);

       //  Make a copy of the list; items are duplicated if you set a duplicator
       //  for the list, otherwise not. Copying a null reference returns a null
       //  reference. Note that this method's behavior changed slightly for CZMQ
       //  v3.x, as it does not set nor respect autofree. It does however let you
       //  duplicate any hash table safely. The old behavior is in zhashx_dup_v2.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT zhashx_t *
           zhashx_dup (zhashx_t *self);

       //  Set a user-defined deallocator for hash items; by default items are not
       //  freed when the hash is destroyed.
       CZMQ_EXPORT void
           zhashx_set_destructor (zhashx_t *self, zhashx_destructor_fn destructor);

       //  Set a user-defined duplicator for hash items; by default items are not
       //  copied when the hash is duplicated.
       CZMQ_EXPORT void
           zhashx_set_duplicator (zhashx_t *self, zhashx_duplicator_fn duplicator);

       //  Set a user-defined deallocator for keys; by default keys are freed
       //  when the hash is destroyed using free().
       CZMQ_EXPORT void
           zhashx_set_key_destructor (zhashx_t *self, zhashx_destructor_fn destructor);

       //  Set a user-defined duplicator for keys; by default keys are duplicated
       //  using strdup.
       CZMQ_EXPORT void
           zhashx_set_key_duplicator (zhashx_t *self, zhashx_duplicator_fn duplicator);

       //  Set a user-defined comparator for keys; by default keys are
       //  compared using strcmp.
       //  The callback function should return zero (0) on matching
       //  items.
       CZMQ_EXPORT void
           zhashx_set_key_comparator (zhashx_t *self, zhashx_comparator_fn comparator);

       //  Set a user-defined hash function for keys; by default keys are
       //  hashed by a modified Bernstein hashing function.
       CZMQ_EXPORT void
           zhashx_set_key_hasher (zhashx_t *self, zhashx_hash_fn hasher);

       //  Make copy of hash table; if supplied table is null, returns null.
       //  Does not copy items themselves. Rebuilds new table so may be slow on
       //  very large tables. NOTE: only works with item values that are strings
       //  since there's no other way to know how to duplicate the item value.
       CZMQ_EXPORT zhashx_t *
           zhashx_dup_v2 (zhashx_t *self);

       //  Self test of this class.
       CZMQ_EXPORT void
           zhashx_test (bool verbose);

       #ifdef CZMQ_BUILD_DRAFT_API
       //  *** Draft method, for development use, may change without warning ***
       //  Same as unpack but uses a user-defined deserializer function to convert
       //  a longstr back into item format.
       CZMQ_EXPORT zhashx_t *
           zhashx_unpack_own (zframe_t *frame, zhashx_deserializer_fn deserializer);

       //  *** Draft method, for development use, may change without warning ***
       //  Same as pack but uses a user-defined serializer function to convert items
       //  into longstr.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT zframe_t *
           zhashx_pack_own (zhashx_t *self, zhashx_serializer_fn serializer);

       #endif // CZMQ_BUILD_DRAFT_API
       Please add '@interface' section in './../src/zhashx.c'.

DESCRIPTION

       zhashx is an extended hash table container with more functionality than zhash, its simpler
       cousin.

       The hash table always has a size that is prime and roughly doubles its size when 75% full.
       In case of hash collisions items are chained in a linked list. The hash table size is
       increased slightly (up to 5 times before roughly doubling the size) when an overly long
       chain (between 1 and 63 items depending on table size) is detected.

EXAMPLE

       From zhashx_test method.

           zhashx_t *hash = zhashx_new ();
           assert (hash);
           assert (zhashx_size (hash) == 0);
           assert (zhashx_first (hash) == NULL);
           assert (zhashx_cursor (hash) == NULL);

           //  Insert some items
           int rc;
           rc = zhashx_insert (hash, "DEADBEEF", "dead beef");
           char *item = (char *) zhashx_first (hash);
           assert (streq ((char *) zhashx_cursor (hash), "DEADBEEF"));
           assert (streq (item, "dead beef"));
           assert (rc == 0);
           rc = zhashx_insert (hash, "ABADCAFE", "a bad cafe");
           assert (rc == 0);
           rc = zhashx_insert (hash, "C0DEDBAD", "coded bad");
           assert (rc == 0);
           rc = zhashx_insert (hash, "DEADF00D", "dead food");
           assert (rc == 0);
           assert (zhashx_size (hash) == 4);

           //  Look for existing items
           item = (char *) zhashx_lookup (hash, "DEADBEEF");
           assert (streq (item, "dead beef"));
           item = (char *) zhashx_lookup (hash, "ABADCAFE");
           assert (streq (item, "a bad cafe"));
           item = (char *) zhashx_lookup (hash, "C0DEDBAD");
           assert (streq (item, "coded bad"));
           item = (char *) zhashx_lookup (hash, "DEADF00D");
           assert (streq (item, "dead food"));

           //  Look for non-existent items
           item = (char *) zhashx_lookup (hash, "foo");
           assert (item == NULL);

           //  Try to insert duplicate items
           rc = zhashx_insert (hash, "DEADBEEF", "foo");
           assert (rc == -1);
           item = (char *) zhashx_lookup (hash, "DEADBEEF");
           assert (streq (item, "dead beef"));

           //  Some rename tests

           //  Valid rename, key is now LIVEBEEF
           rc = zhashx_rename (hash, "DEADBEEF", "LIVEBEEF");
           assert (rc == 0);
           item = (char *) zhashx_lookup (hash, "LIVEBEEF");
           assert (streq (item, "dead beef"));

           //  Trying to rename an unknown item to a non-existent key
           rc = zhashx_rename (hash, "WHATBEEF", "NONESUCH");
           assert (rc == -1);

           //  Trying to rename an unknown item to an existing key
           rc = zhashx_rename (hash, "WHATBEEF", "LIVEBEEF");
           assert (rc == -1);
           item = (char *) zhashx_lookup (hash, "LIVEBEEF");
           assert (streq (item, "dead beef"));

           //  Trying to rename an existing item to another existing item
           rc = zhashx_rename (hash, "LIVEBEEF", "ABADCAFE");
           assert (rc == -1);
           item = (char *) zhashx_lookup (hash, "LIVEBEEF");
           assert (streq (item, "dead beef"));
           item = (char *) zhashx_lookup (hash, "ABADCAFE");
           assert (streq (item, "a bad cafe"));

           //  Test keys method
           zlistx_t *keys = zhashx_keys (hash);
           assert (zlistx_size (keys) == 4);
           zlistx_destroy (&keys);

           zlistx_t *values = zhashx_values (hash);
           assert (zlistx_size (values) == 4);
           zlistx_destroy (&values);

           //  Test dup method
           zhashx_t *copy = zhashx_dup (hash);
           assert (zhashx_size (copy) == 4);
           item = (char *) zhashx_lookup (copy, "LIVEBEEF");
           assert (item);
           assert (streq (item, "dead beef"));
           zhashx_destroy (&copy);

           //  Test pack/unpack methods
           zframe_t *frame = zhashx_pack (hash);
           copy = zhashx_unpack (frame);
           zframe_destroy (&frame);
           assert (zhashx_size (copy) == 4);
           item = (char *) zhashx_lookup (copy, "LIVEBEEF");
           assert (item);
           assert (streq (item, "dead beef"));
           zhashx_destroy (&copy);

           #ifdef CZMQ_BUILD_DRAFT_API
           //  Test own pack/unpack methods
           zhashx_t *own_hash = zhashx_new ();
           zhashx_set_destructor (own_hash, s_test_destroy_int);
           assert (own_hash);
           int *val1 = (int *) zmalloc (sizeof (int));
           int *val2 = (int *) zmalloc (sizeof (int));
           *val1 = 25;
           *val2 = 100;
           zhashx_insert (own_hash, "val1", val1);
           zhashx_insert (own_hash, "val2", val2);
           frame = zhashx_pack_own (own_hash, s_test_serialize_int);
           copy = zhashx_unpack_own (frame, s_test_deserialze_int);
           zhashx_set_destructor (copy, s_test_destroy_int);
           zframe_destroy (&frame);
           assert (zhashx_size (copy) == 2);
           assert (*((int *) zhashx_lookup (copy, "val1")) == 25);
           assert (*((int *) zhashx_lookup (copy, "val2")) == 100);
           zhashx_destroy (&copy);
           zhashx_destroy (&own_hash);
           #endif // CZMQ_BUILD_DRAFT_API

           //  Test save and load
           zhashx_comment (hash, "This is a test file");
           zhashx_comment (hash, "Created by %s", "czmq_selftest");
           zhashx_save (hash, ".cache");
           copy = zhashx_new ();
           assert (copy);
           zhashx_load (copy, ".cache");
           item = (char *) zhashx_lookup (copy, "LIVEBEEF");
           assert (item);
           assert (streq (item, "dead beef"));
           zhashx_destroy (&copy);
           zsys_file_delete (".cache");

           //  Delete a item
           zhashx_delete (hash, "LIVEBEEF");
           item = (char *) zhashx_lookup (hash, "LIVEBEEF");
           assert (item == NULL);
           assert (zhashx_size (hash) == 3);

           //  Check that the queue is robust against random usage
           struct {
               char name [100];
               bool exists;
           } testset [200];
           memset (testset, 0, sizeof (testset));
           int testmax = 200, testnbr, iteration;

           srandom ((unsigned) time (NULL));
           for (iteration = 0; iteration < 25000; iteration++) {
               testnbr = randof (testmax);
               assert (testnbr != testmax);
               assert (testnbr < testmax);
               if (testset [testnbr].exists) {
                   item = (char *) zhashx_lookup (hash, testset [testnbr].name);
                   assert (item);
                   zhashx_delete (hash, testset [testnbr].name);
                   testset [testnbr].exists = false;
               }
               else {
                   sprintf (testset [testnbr].name, "%x-%x", rand (), rand ());
                   if (zhashx_insert (hash, testset [testnbr].name, "") == 0)
                       testset [testnbr].exists = true;
               }
           }
           //  Test 10K lookups
           for (iteration = 0; iteration < 10000; iteration++)
               item = (char *) zhashx_lookup (hash, "DEADBEEFABADCAFE");

           //  Destructor should be safe to call twice
           zhashx_destroy (&hash);
           zhashx_destroy (&hash);
           assert (hash == NULL);

           //  Test randof() limits - should be within (0..testmax)
           //  and randomness distribution - should not have (many) zero-counts
           //  If there are - maybe the ZSYS_RANDOF_MAX is too big for this platform
           //  Note: This test can take a while on systems with weak floating point HW
           testmax = 999;
           size_t rndcnt[999];
           assert ((sizeof (rndcnt)/sizeof(rndcnt[0])) == testmax);
           memset (rndcnt, 0, sizeof (rndcnt));
           for (iteration = 0; iteration < 10000000; iteration++) {
               testnbr = randof (testmax);
               assert (testnbr != testmax);
               assert (testnbr < testmax);
               assert (testnbr >= 0);
               rndcnt[testnbr]++;
           }
           int rndmisses = 0;
           for (iteration = 0; iteration < testmax; iteration++) {
               if (rndcnt[iteration] == 0) {
                   zsys_warning("zhashx_test() : random distribution fault : got 0 hits for %d/%d",
                       iteration, testmax);
                   rndmisses++;
               }
           }
           //  Too many misses are suspicious... we can lose half the entries
           //  for each bit not used in the assumed ZSYS_RANDOF_MAX...
           assert ( (rndmisses < (testmax / 3 )) );

           //  Test destructor; automatically copies and frees string values
           hash = zhashx_new ();
           assert (hash);
           zhashx_set_destructor (hash, (zhashx_destructor_fn *) zstr_free);
           zhashx_set_duplicator (hash, (zhashx_duplicator_fn *) strdup);
           char value [255];
           strcpy (value, "This is a string");
           rc = zhashx_insert (hash, "key1", value);
           assert (rc == 0);
           strcpy (value, "Ring a ding ding");
           rc = zhashx_insert (hash, "key2", value);
           assert (rc == 0);
           assert (streq ((char *) zhashx_lookup (hash, "key1"), "This is a string"));
           assert (streq ((char *) zhashx_lookup (hash, "key2"), "Ring a ding ding"));
           zhashx_destroy (&hash);

           //  Test purger and shrinker: no data should end up unreferenced in valgrind
           hash = zhashx_new ();
           assert (hash);
           zhashx_set_destructor (hash, (zhashx_destructor_fn *) zstr_free);
           zhashx_set_duplicator (hash, (zhashx_duplicator_fn *) strdup);
           char valuep [255];
           strcpy (valuep, "This is a string");
           rc = zhashx_insert (hash, "key1", valuep);
           assert (rc == 0);
           strcpy (valuep, "Ring a ding ding");
           rc = zhashx_insert (hash, "key2", valuep);
           assert (rc == 0);
           strcpy (valuep, "Cartahena delenda est");
           rc = zhashx_insert (hash, "key3", valuep);
           assert (rc == 0);
           strcpy (valuep, "So say we all!");
           rc = zhashx_insert (hash, "key4", valuep);
           assert (rc == 0);
           assert (streq ((char *) zhashx_lookup (hash, "key1"), "This is a string"));
           assert (streq ((char *) zhashx_lookup (hash, "key2"), "Ring a ding ding"));
           assert (streq ((char *) zhashx_lookup (hash, "key3"), "Cartahena delenda est"));
           assert (streq ((char *) zhashx_lookup (hash, "key4"), "So say we all!"));
           zhashx_purge (hash);
           zhashx_destroy (&hash);

           #if defined (__WINDOWS__)
           zsys_shutdown();
           #endif

AUTHORS

       The czmq manual was written by the authors in the AUTHORS file.

RESOURCES

       Main web site:

       Report bugs to the email <zeromq-dev@lists.zeromq.org[1]>

COPYRIGHT

       Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ,
       the high-level C binding for 0MQ: http://czmq.zeromq.org. This Source Code Form is subject
       to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not
       distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE
       included with the czmq distribution.

NOTES

        1. zeromq-dev@lists.zeromq.org
           mailto:zeromq-dev@lists.zeromq.org