array_it.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
#ifndef ARRAY_IT_H
#define ARRAY_IT_H
 
#include <cassert>
#include <tuple>
#include <aleph.H>
#include <ahDefs.H>
#include <htlist.H>
#include <ah-errors.H>
 
namespace Aleph {
 
template <typename T>
class Array_Container;
 
template <class T>
class Array_Iterator
{
  T *ptr = nullptr;
  long dim = 0;
  long num_items = 0;
  long idx = 0;
  long first = 0;
  long last = 0;
  long pos = 0;
 
  static void ensure_base_pointer(T *p, const size_t sz)
  {
    ah_invalid_argument_if(sz > 0 and p == nullptr)
      << "Array_Iterator(): ptr == nullptr with dim > 0";
  }
 
  static void ensure_num_items(size_t sz, size_t n)
  {
    ah_domain_error_if(n > sz) << "Array_Iterator(): num_items greater than dim";
  }
 
  static void ensure_index_in_range(const size_t sz, const long value, const char *msg)
  {
    ah_domain_error_if(value < 0 or static_cast<size_t>(value) >= sz) << msg;
  }
 
  static long compute_last_index(const size_t n) noexcept
  {
    return n == 0 ? 0 : static_cast<long>(n - 1);
  }
 
public:
  using Item_Type = T;
 
  T *get_base() noexcept
  {
    return ptr;
  }
 
  [[nodiscard]] constexpr const T *get_base() const noexcept
  {
    return ptr;
  }
 
  Array_Iterator() = default;
 
  Array_Iterator(T *p, const size_t sz, const size_t n)
    : ptr(p), dim(sz), num_items(n), last(compute_last_index(n))
  {
    ensure_base_pointer(ptr, sz);
    ensure_num_items(sz, n);
  }
 
  Array_Iterator(NoExceptionCtor, T *p, const size_t sz, const size_t n)
    : ptr(p), dim(sz), num_items(n), last(compute_last_index(n))
  {
    assert(ptr);
    assert(num_items <= dim);
  }
 
  Array_Iterator(T *p, const size_t sz, const size_t n, const long f, const long l)
    : ptr(p), dim(sz), num_items(n), idx(f), first(f), last(n == 0 ? f : l)
  {
    ensure_base_pointer(ptr, sz);
    ensure_num_items(sz, n);
    ah_domain_error_if(dim == 0 and num_items > 0)
      << "Array_Iterator(): dim == 0 but num_items > 0";
    if (dim > 0)
      {
        ensure_index_in_range(dim, first, "Array_Iterator(): first >= dim");
        ensure_index_in_range(dim, last, "Array_Iterator(): last >= dim");
      }
  }
 
  Array_Iterator(NoExceptionCtor, T *p, const size_t sz, const size_t n, const long f, const long l)
    : ptr(p), dim(sz), num_items(n), idx(f), first(f), last(n == 0 ? f : l)
  {
    assert(ptr);
    assert(num_items <= dim);
    assert(dim == 0 or (first >= 0 and first < dim));
    assert(dim == 0 or (last >= 0 and last < dim));
  }
 
  explicit Array_Iterator(const Array_Container<T> &c)
    : Array_Iterator(c.get_base(), c.capacity(), c.size())
  {}
 
  [[nodiscard]] bool has_curr() const noexcept
  {
    return pos >= 0 and pos < num_items;
  }
 
  [[nodiscard]] bool is_last() const noexcept
  {
    return has_curr() and pos == num_items - 1;
  }
 
  [[nodiscard]] constexpr long get_pos() const noexcept
  {
    return pos;
  }
 
  T &get_curr_ne() const noexcept
  {
    return ptr[idx];
  }
 
  T &get_curr() const
  {
    ah_underflow_error_if(pos < 0) << "Array_Iterator::get_curr(): no current item";
 
    ah_overflow_error_if(pos >= num_items) << "Array_Iterator::get_curr(): no current item";
 
    return ptr[idx];
  }
 
  void next_ne() noexcept
  {
    if (++idx == dim)
      idx = 0;
    ++pos;
  }
 
  void next()
  {
    ah_overflow_error_if(num_items == 0 or pos >= num_items)
      << "Array_Iterator::next(): no current item";
    next_ne();
  }
 
  void prev_ne() noexcept
  {
    if (--idx < 0)
      idx = dim - 1;
    --pos;
  }
 
  void prev()
  {
    ah_underflow_error_if(num_items == 0 or pos < 0) << "Array_Iterator::prev(): no current item";
    prev_ne();
  }
 
  void reset() noexcept
  {
    idx = first;
    pos = 0;
  }
 
  void reset_first() noexcept
  {
    reset();
  }
 
  void reset_last() noexcept
  {
    idx = last;
    pos = num_items - 1;
  }
 
  void set_pos(const long new_pos) noexcept
  {
    pos = new_pos;
    if (dim > 0)
      idx = (first + new_pos) % dim;
  }
 
  void end() noexcept
  {
    set_pos(num_items);
  }
};
 
template <typename T>
[[nodiscard]] inline Array_Iterator<T> get_array_it(const T *array, size_t n)
{
  return Array_Iterator<T>(const_cast<T *>(array), n, n);
}
 
template <typename T>
[[nodiscard]] inline Array_Container<T> make_array_container(T *array, size_t n)
{
  return Array_Container<T>(array, n);
}
 
template <typename T>
class Array_Container : public GenericTraverse<Array_Container<T>>,
                        public LocateFunctions<Array_Container<T>, T>,
                        public FunctionalMethods<Array_Container<T>, T>,
                        public GenericKeys<Array_Container<T>, T>,
                        public EqualToMethod<Array_Container<T>>,
                        public StlAlephIterator<Array_Container<T>>
{
  T *base = nullptr;
  size_t n = 0;
 
public:
  using Item_Type = T;
 
  T *get_base() const noexcept
  {
    return base;
  }
 
  Array_Container(T *base_ptr, const size_t d) : base(base_ptr), n(d)
  {
    // empty
  }
 
  [[nodiscard]] constexpr bool is_empty() const noexcept
  {
    return n == 0;
  }
 
  [[nodiscard]] constexpr size_t size() const noexcept
  {
    return n;
  }
 
  [[nodiscard]] constexpr size_t capacity() const noexcept
  {
    return n;
  }
 
  T &get_first() const
  {
    ah_underflow_error_if(n == 0) << "Array_Container::get_first(): n == 0";
    return base[0];
  }
 
  T &get_last() const
  {
    ah_underflow_error_if(n == 0) << "Array_Container::get_last(): n == 0";
    return base[n - 1];
  }
 
  struct Iterator : public Array_Iterator<T>
  {
    Iterator(const Array_Container &c) : Array_Iterator<T>(c.base, c.n, c.n) {}
  };
 
  Iterator get_it() const
  {
    return Iterator(*this);
  }
};
 
}  // end namespace Aleph
 
#endif  // ARRAY_IT_H