ucx: src/cx/iterator.h@d4baf4dd55c3 (annotated)

src/cx/iterator.h@d4baf4dd55c3 (annotated)

src/cx/iterator.h

Thu, 23 May 2024 19:29:14 +0200

author: Mike Becker <universe@uap-core.de>
date: Thu, 23 May 2024 19:29:14 +0200
changeset 853: d4baf4dd55c3
parent 852: 16e2a3391e88
child 854: fe0d69d72bcd
permissions: -rw-r--r--

simplify iterator structures

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *   1. Redistributions of source code must retain the above copyright
  *      notice, this list of conditions and the following disclaimer.
  *
  *   2. Redistributions in binary form must reproduce the above copyright
  *      notice, this list of conditions and the following disclaimer in the
  *      documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /**
  * \file iterator.h
  * \brief Interface for iterator implementations.
  * \author Mike Becker
  * \author Olaf Wintermann
  * \copyright 2-Clause BSD License
  */
 #ifndef UCX_ITERATOR_H
 #define UCX_ITERATOR_H
 #include "common.h"
 #define CX_ITERATOR_BASE \
     /** \
      * True iff the iterator points to valid data. \
      */ \
     __attribute__ ((__nonnull__)) \
     bool (*valid)(void const *); \
     /** \
      * Returns a pointer to the current element. \
      * \
      * When valid returns false, the behavior of this function is undefined. \
      */ \
     __attribute__ ((__nonnull__)) \
     void *(*current)(void const *); \
     /** \
      * Original implementation in case the function needs to be wrapped. \
      */ \
     __attribute__ ((__nonnull__)) \
     void *(*current_impl)(void const *); \
     /** \
      * Advances the iterator. \
      * \
      * When valid returns false, the behavior of this function is undefined. \
      */ \
     __attribute__ ((__nonnull__)) \
     void (*next)(void *); \
     /** \
      * Indicates whether this iterator may remove elements. \
      */ \
     bool mutating; \
     /** \
      * Internal flag for removing the current element when advancing. \
      */ \
     bool remove;
 /**
  * Internal iterator struct - use CxIterator.
  */
 struct cx_iterator_s {
     CX_ITERATOR_BASE
     /**
      * Handle for the current element.
      */
     void *elem_handle;
     /**
      * Handle for the source collection, if any.
      */
     union {
         /**
          * Access for mutating iterators.
          */
         void *m;
         /**
          * Access for normal iterators.
          */
         void const *c;
     } src_handle;
     /**
      * Field for storing a key-value pair.
      * May be used by iterators that iterate over k/v-collections.
      */
     struct {
         /**
          * A pointer to the key.
          */
         void const *key;
         /**
          * A pointer to the value.
          */
         void *value;
     } kv_data;
     /**
      * Field for storing a slot number.
      * May be used by iterators that iterate over multi-bucket collections.
      */
     size_t slot;
     /**
      * If the iterator is position-aware, contains the index of the element in the underlying collection.
      * Otherwise, this field is usually uninitialized.
      */
     size_t index;
     /**
      * The size of an individual element.
      */
     size_t elem_size;
     /**
      * May contain the total number of elements, if known.
      * Shall be set to \c SIZE_MAX when the total number is unknown during iteration.
      */
     size_t elem_count;
 };
 /**
  * Iterator type.
  *
  * An iterator points to a certain element in a (possibly unbounded) chain of elements.
  * Iterators that are based on collections (which have a defined "first" element), are supposed
  * to be "position-aware", which means that they keep track of the current index within the collection.
  *
  * @note Objects that are pointed to by an iterator are always mutable through that iterator. However,
  * any concurrent mutation of the collection other than by this iterator makes this iterator invalid
  * and it must not be used anymore.
  */
 typedef struct cx_iterator_s CxIterator;
 /**
  * Checks if the iterator points to valid data.
  *
  * This is especially false for past-the-end iterators.
  *
  * @param iter the iterator
  * @return true iff the iterator points to valid data
  */
 #define cxIteratorValid(iter) (iter).valid(&(iter))
 /**
  * Returns a pointer to the current element.
  *
  * The behavior is undefined if this iterator is invalid.
  *
  * @param iter the iterator
  * @return a pointer to the current element
  */
 #define cxIteratorCurrent(iter) (iter).current(&iter)
 /**
  * Advances the iterator to the next element.
  *
  * @param iter the iterator
  */
 #define cxIteratorNext(iter) (iter).next(&iter)
 /**
  * Flags the current element for removal, if this iterator is mutating.
  *
  * @param iter the iterator
  */
 #define cxIteratorFlagRemoval(iter) (iter).remove |= (iter).mutating
 /**
  * Loops over an iterator.
  * @param type the type of the elements
  * @param elem the name of the iteration variable
  * @param iter the iterator
  */
 #define cx_foreach(type, elem, iter) \
 for (type elem; cxIteratorValid(iter) && (elem = (type)cxIteratorCurrent(iter)) != NULL ; cxIteratorNext(iter))
 /**
  * Creates an iterator for the specified plain array.
  *
  * The \p array can be \c NULL in which case the iterator will be immediately
  * initialized such that #cxIteratorValid() returns \c false.
  *
  *
  * @param array a pointer to the array (can be \c NULL)
  * @param elem_size the size of one array element
  * @param elem_count the number of elements in the array
  * @return an iterator for the specified array
  */
 __attribute__((__warn_unused_result__))
 CxIterator cxIterator(
         void const *array,
         size_t elem_size,
         size_t elem_count
 );
 /**
  * Creates a mutating iterator for the specified plain array.
  *
  * While the iterator is in use, the array may only be altered by removing
  * elements through #cxIteratorFlagRemoval(). Every other change to the array
  * will bring this iterator to an undefined state.
  *
  * When \p remove_keeps_order is set to \c false, removing an element will only
  * move the last element to the position of the removed element, instead of
  * moving all subsequent elements by one. Usually, when the order of elements is
  * not important, this parameter should be set to \c false.
  *
  * The \p array can be \c NULL in which case the iterator will be immediately
  * initialized such that #cxIteratorValid() returns \c false.
  *
  *
  * @param array a pointer to the array (can be \c NULL)
  * @param elem_size the size of one array element
  * @param elem_count the number of elements in the array
  * @param remove_keeps_order \c true if the order of elements must be preserved
  * when removing an element
  * @return an iterator for the specified array
  */
 __attribute__((__warn_unused_result__))
 CxIterator cxMutIterator(
         void *array,
         size_t elem_size,
         size_t elem_count,
         bool remove_keeps_order
 );
 #endif // UCX_ITERATOR_H

Mercurial > hg > ucx / annotate

src/cx/iterator.h@d4baf4dd55c3 (annotated)

src/cx/iterator.h