<class name = "zlistx" state = "stable">
    <!--
    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/.
    -->
    extended generic list container

    <callback_type name = "destructor_fn">
        Destroy an item
        <argument name = "item" type = "anything" by_reference = "1" />
    </callback_type>

    <callback_type name = "duplicator_fn">
        Duplicate an item
        <argument name = "item" type = "anything" mutable = "0" />
        <return type = "anything" />
    </callback_type>

    <callback_type name = "comparator_fn">
        Compare two items, for sorting
        <argument name = "item1" type = "anything" mutable = "0" />
        <argument name = "item2" type = "anything" mutable = "0" />
        <return type = "integer" />
    </callback_type>

    <constructor>
        Create a new, empty list.
    </constructor>

    <destructor>
        Destroy a list. If an item destructor was specified, all items in the
        list are automatically destroyed as well.
    </destructor>

    <method name = "add_start">
        Add an item to the head of the list. Calls the item duplicator, if any,
        on the item. Resets cursor to list head. Returns an item handle on
        success, NULL if memory was exhausted.
        <argument name = "item" type = "anything" mutable = "1" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "add_end">
        Add an item to the tail of the list. Calls the item duplicator, if any,
        on the item. Resets cursor to list head. Returns an item handle on
        success, NULL if memory was exhausted.
        <argument name = "item" type = "anything" mutable = "1" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "size">
        Return the number of items in the list
        <return type = "size" />
    </method>

    <method name = "head">
        Return first item in the list, or null, leaves the cursor
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "tail">
        Return last item in the list, or null, leaves the cursor
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "first">
        Return the item at the head of list. If the list is empty, returns NULL.
        Leaves cursor pointing at the head item, or NULL if the list is empty.
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "next">
        Return the next item. At the end of the list (or in an empty list),
        returns NULL. Use repeated zlistx_next () calls to work through the list
        from zlistx_first (). First time, acts as zlistx_first().
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "prev">
        Return the previous item. At the start of the list (or in an empty list),
        returns NULL. Use repeated zlistx_prev () calls to work through the list
        backwards from zlistx_last (). First time, acts as zlistx_last().
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "last">
        Return the item at the tail of list. If the list is empty, returns NULL.
        Leaves cursor pointing at the tail item, or NULL if the list is empty.
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "item">
        Returns the value of the item at the cursor, or NULL if the cursor is
        not pointing to an item.
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "cursor">
        Returns the handle of the item at the cursor, or NULL if the cursor is
        not pointing to an item.
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "handle_item" singleton = "1">
        Returns the item associated with the given list handle, or NULL if passed
        in handle is NULL. Asserts that the passed in handle points to a list element.
        <argument name = "handle" type = "anything" mutable = "1" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "find">
        Find an item in the list, searching from the start. Uses the item
        comparator, if any, else compares item values directly. Returns the
        item handle found, or NULL. Sets the cursor to the found item, if any.
        <argument name = "item" type = "anything" mutable = "1" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "detach">
        Detach an item from the list, using its handle. The item is not modified,
        and the caller is responsible for destroying it if necessary. If handle is
        null, detaches the first item on the list. Returns item that was detached,
        or null if none was. If cursor was at item, moves cursor to previous item,
        so you can detach items while iterating forwards through a list.
        <argument name = "handle" type = "anything" mutable = "1" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "detach_cur">
        Detach item at the cursor, if any, from the list. The item is not modified,
        and the caller is responsible for destroying it as necessary. Returns item
        that was detached, or null if none was. Moves cursor to previous item, so
        you can detach items while iterating forwards through a list.
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "delete">
        Delete an item, using its handle. Calls the item destructor if any is
        set. If handle is null, deletes the first item on the list. Returns 0
        if an item was deleted, -1 if not. If cursor was at item, moves cursor
        to previous item, so you can delete items while iterating forwards
        through a list.
        <argument name = "handle" type = "anything" mutable = "1" />
        <return type = "integer" />
    </method>

    <method name = "move_start">
        Move an item to the start of the list, via its handle.
        <argument name = "handle" type = "anything" mutable = "1" />
    </method>

    <method name = "move_end">
        Move an item to the end of the list, via its handle.
        <argument name = "handle" type = "anything" mutable = "1" />
    </method>

    <method name = "purge">
        Remove all items from the list, and destroy them if the item destructor
        is set.
    </method>

    <method name = "sort">
        Sort the list. If an item comparator was set, calls that to compare
        items, otherwise compares on item value. The sort is not stable, so may
        reorder equal items.
    </method>

    <method name = "insert">
        Create a new node and insert it into a sorted list. Calls the item
        duplicator, if any, on the item. If low_value is true, starts searching
        from the start of the list, otherwise searches from the end. Use the item
        comparator, if any, to find where to place the new node. Returns a handle
        to the new node, or NULL if memory was exhausted. Resets the cursor to the
        list head.
        <argument name = "item" type = "anything" mutable = "1" />
        <argument name = "low_value" type = "boolean" />
        <return type = "anything" mutable = "1" />
    </method>

    <method name = "reorder">
        Move an item, specified by handle, into position in a sorted list. Uses
        the item comparator, if any, to determine the new location. If low_value
        is true, starts searching from the start of the list, otherwise searches
        from the end.
        <argument name = "handle" type = "anything" mutable = "1" />
        <argument name = "low_value" type = "boolean" />
    </method>

    <method name = "dup">
        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.
        <return type = "zlistx" fresh = "0" />
    </method>

    <method name = "set destructor">
        Set a user-defined deallocator for list items; by default items are not
        freed when the list is destroyed.
        <argument name = "destructor" type = "zlistx_destructor_fn" callback = "1" />
    </method>

    <method name = "set duplicator">
        Set a user-defined duplicator for list items; by default items are not
        copied when the list is duplicated.
        <argument name = "duplicator" type = "zlistx_duplicator_fn" callback = "1" />
    </method>

    <method name = "set comparator">
        Set a user-defined comparator for zlistx_find and zlistx_sort; the method
        must return -1, 0, or 1 depending on whether item1 is less than, equal to,
        or greater than, item2.
        <argument name = "comparator" type = "zlistx_comparator_fn" callback = "1" />
    </method>

   <method name = "pack" state = "draft">
        Serialize list to a binary frame that can be sent in a message.
        The packed format is compatible with the 'strings' type implemented by zproto:

           ; A list of strings
           list            = list-count *longstr
           list-count      = number-4

           ; Strings are always length + text contents
           longstr         = number-4 *VCHAR

           ; Numbers are unsigned integers in network byte order
           number-4        = 4OCTET

        <return type = "zframe" fresh = "1" />
    </method>

    <constructor name = "unpack" state = "draft">
        Unpack binary frame into a new list. Packed data must follow format
        defined by zlistx_pack. List is set to autofree. An empty frame
        unpacks to an empty list.
        <argument name = "frame" type = "zframe" />
    </constructor>
</class>
