1<?php
2
3/**
4 * Hoa
5 *
6 *
7 * @license
8 *
9 * New BSD License
10 *
11 * Copyright © 2007-2017, Hoa community. All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions are met:
15 *     * Redistributions of source code must retain the above copyright
16 *       notice, this list of conditions and the following disclaimer.
17 *     * Redistributions in binary form must reproduce the above copyright
18 *       notice, this list of conditions and the following disclaimer in the
19 *       documentation and/or other materials provided with the distribution.
20 *     * Neither the name of the Hoa nor the names of its contributors may be
21 *       used to endorse or promote products derived from this software without
22 *       specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36
37namespace Hoa\Iterator;
38
39/**
40 * Class \Hoa\Iterator\Counter.
41 *
42 * A counter.
43 *
44 * @copyright  Copyright © 2007-2017 Hoa community
45 * @license    New BSD License
46 */
47class Counter implements Iterator
48{
49    /**
50     * From (lower bound).
51     *
52     * @var int
53     */
54    protected $_from = 0;
55
56    /**
57     * Current key.
58     *
59     * @var int
60     */
61    protected $_key  = 0;
62
63    /**
64     * Current index.
65     *
66     * @var int
67     */
68    protected $_i    = 0;
69
70    /**
71     * To (upper bound).
72     *
73     * @var int
74     */
75    protected $_to   = 0;
76
77    /**
78     * Step.
79     *
80     * @var int
81     */
82    protected $_step = 0;
83
84
85
86    /**
87     * Constructor.
88     * Equivalent to:
89     *     for($i = $from; $i < $to; $i += $step)
90     *
91     * @param   int  $from    Start value.
92     * @param   int  $to      Maximum value.
93     * @param   int  $step    Step.
94     * @throws  \Hoa\Iterator\Exception
95     */
96    public function __construct($from, $to, $step)
97    {
98        if ($step <= 0) {
99            throw new Exception(
100                'The step must be non-negative; given %d.',
101                0,
102                $step
103            );
104        }
105
106        $this->_from = $from;
107        $this->_to   = $to;
108        $this->_step = $step;
109
110        return;
111    }
112
113    /**
114     * Return the current element.
115     *
116     * @return  int
117     */
118    public function current()
119    {
120        return $this->_i;
121    }
122
123    /**
124     * Return the key of the current element.
125     *
126     * @return  int
127     */
128    public function key()
129    {
130        return $this->_key;
131    }
132
133    /**
134     * Move forward to next element.
135     *
136     * @return  void
137     */
138    public function next()
139    {
140        ++$this->_key;
141        $this->_i += $this->_step;
142
143        return;
144    }
145
146    /**
147     * Rewind the iterator to the first element.
148     *
149     * @return  void
150     */
151    public function rewind()
152    {
153        $this->_key = 0;
154        $this->_i   = $this->_from;
155
156        return;
157    }
158
159    /**
160     * Check if current position is valid.
161     *
162     * @return  bool
163     */
164    public function valid()
165    {
166        return $this->_i < $this->_to;
167    }
168}
169