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\Math;
38
39/**
40 * Class \Hoa\Math\Context.
41 *
42 * @copyright  Copyright © 2007-2017 Hoa community
43 * @license    New BSD License
44 */
45class Context
46{
47    /**
48     * List of supported functions: identifier => values as callable.
49     *
50     * @var \ArrayObject
51     */
52    protected $_functions = null;
53
54    /**
55     * List of supported constants: identifier => values.
56     *
57     * @var \ArrayObject
58     */
59    protected $_constants = null;
60
61    /**
62     * List of supported variables: identifier => values as callable.
63     *
64     * @var \ArrayObject
65     */
66    protected $_variables = null;
67
68
69
70    /**
71     * Initialize constants and functions.
72     *
73     */
74    public function __construct()
75    {
76        $this->initializeConstants();
77        $this->initializeFunctions();
78        $this->initializeVariables();
79
80        return;
81    }
82
83    /**
84     * Add a constant.
85     *
86     * @param   string  $name     Constant name.
87     * @param   mixed   $value    Value.
88     * @return  void
89     * @throws  \Hoa\Math\Exception\AlreadyDefinedConstant
90     */
91    public function addConstant($name, $value)
92    {
93        if (true === $this->_constants->offsetExists($name)) {
94            throw new Exception\AlreadyDefinedConstant(
95                'Constant %s is already defined.',
96                0,
97                $name
98            );
99        }
100
101        $this->_constants[$name] = $value;
102
103        return;
104    }
105
106    /**
107     * Get a constant.
108     *
109     * @param   string  $name    Constant name.
110     * @return  mixed
111     * @throws  \Hoa\Math\Exception\UnknownConstant
112     */
113    public function getConstant($name)
114    {
115        if (false === $this->_constants->offsetExists($name)) {
116            throw new Exception\UnknownConstant(
117                'Constant %s does not exist.',
118                1,
119                $name
120            );
121        }
122
123        return $this->_constants[$name];
124    }
125
126    /**
127     * Get constants.
128     *
129     * @return  \ArrayObject
130     */
131    public function getConstants()
132    {
133        return $this->_constants;
134    }
135
136    /**
137     * Add a function.
138     *
139     * @param   string  $name        Function name.
140     * @param   mixed   $callable    Callable.
141     * @return  void
142     * @throws  \Hoa\Math\Exception\UnknownFunction
143     */
144    public function addFunction($name, $callable = null)
145    {
146        if (null === $callable) {
147            if (false === function_exists($name)) {
148                throw new Exception\UnknownFunction(
149                    'Function %s does not exist, cannot add it.',
150                    2,
151                    $name
152                );
153            }
154
155            $callable = $name;
156        }
157
158        $this->_functions[$name] = xcallable($callable);
159
160        return;
161    }
162
163    /**
164     * Get a function.
165     *
166     * @param   string  $name    Function name.
167     * @return  \Hoa\Consistency\Xcallable
168     * @throws  \Hoa\Math\Exception\UnknownFunction
169     */
170    public function getFunction($name)
171    {
172        if (false === $this->_functions->offsetExists($name)) {
173            throw new Exception\UnknownFunction(
174                'Function %s does not exist.',
175                3,
176                $name
177            );
178        }
179
180        return $this->_functions[$name];
181    }
182
183    /**
184     * Get functions.
185     *
186     * @return  \ArrayObject
187     */
188    public function getFunctions()
189    {
190        return $this->_functions;
191    }
192
193    /**
194     * Add a variable.
195     *
196     * @param   string    $name        Variable name.
197     * @param   callable  $callable    Callable.
198     * @return  void
199     */
200    public function addVariable($name, callable $callable)
201    {
202        $this->_variables[$name] = xcallable($callable);
203
204        return;
205    }
206
207    /**
208     * Get a variable.
209     *
210     * @param   string   $name    Variable name.
211     * @return  callable
212     * @throws  \Hoa\Math\Exception\UnknownVariable
213     */
214    public function getVariable($name)
215    {
216        if (false === $this->_variables->offsetExists($name)) {
217            throw new Exception\UnknownVariable(
218                'Variable %s does not exist.',
219                4,
220                $name
221            );
222        }
223
224        return $this->_variables[$name]($this);
225    }
226
227    /**
228     * Get variables.
229     *
230     * @return \ArrayObject
231     */
232    public function getVariables()
233    {
234        return $this->_variables;
235    }
236
237    /**
238     * Initialize constants mapping.
239     *
240     * @return void
241     */
242    protected function initializeConstants()
243    {
244        static $_constants = null;
245
246        if (null === $_constants) {
247            $_constants = new \ArrayObject([
248                'PI'               => M_PI,
249                'PI_2'             => M_PI_2,
250                'PI_4'             => M_PI_4,
251                'E'                => M_E,
252                'SQRT_PI'          => M_SQRTPI,
253                'SQRT_2'           => M_SQRT2,
254                'SQRT_3'           => M_SQRT3,
255                'LN_PI'            => M_LNPI,
256                'LOG_2E'           => M_LOG2E,
257                'LOG_10E'          => M_LOG10E,
258                'LN_2'             => M_LN2,
259                'LN_10'            => M_LN10,
260                'ONE_OVER_PI'      => M_1_PI,
261                'TWO_OVER_PI'      => M_2_PI,
262                'TWO_OVER_SQRT_PI' => M_2_SQRTPI,
263                'ONE_OVER_SQRT_2'  => M_SQRT1_2,
264                'EULER'            => M_EULER,
265                'INFINITE'         => INF
266            ]);
267        }
268
269        $this->_constants = $_constants;
270
271        return;
272    }
273
274    /**
275     * Initialize functions mapping.
276     *
277     * @return void
278     */
279    protected function initializeFunctions()
280    {
281        static $_functions = null;
282
283        if (null === $_functions) {
284            $average = function () {
285                $arguments = func_get_args();
286
287                return array_sum($arguments) / count($arguments);
288            };
289
290            $_functions = new \ArrayObject([
291                'abs'     => xcallable('abs'),
292                'acos'    => xcallable('acos'),
293                'asin'    => xcallable('asin'),
294                'atan'    => xcallable('atan'),
295                'average' => xcallable($average),
296                'avg'     => xcallable($average),
297                'ceil'    => xcallable('ceil'),
298                'cos'     => xcallable('cos'),
299                'count'   => xcallable(function () { return count(func_get_args()); }),
300                'deg2rad' => xcallable('deg2rad'),
301                'exp'     => xcallable('exp'),
302                'floor'   => xcallable('floor'),
303                'ln'      => xcallable('log'),
304                'log'     => xcallable(function ($value, $base = 10) { return log($value, $base); }),
305                'max'     => xcallable('max'),
306                'min'     => xcallable('min'),
307                'pow'     => xcallable('pow'),
308                'rad2deg' => xcallable('rad2deg'),
309                'round'   => xcallable(function ($value, $precision = 0) { return round($value, $precision); }),
310                'sin'     => xcallable('sin'),
311                'sqrt'    => xcallable('sqrt'),
312                'sum'     => xcallable(function () { return array_sum(func_get_args()); }),
313                'tan'     => xcallable('tan')
314            ]);
315        }
316
317        $this->_functions = $_functions;
318
319        return;
320    }
321
322    /**
323     * Initialize variables mapping.
324     *
325     * @return void
326     */
327    protected function initializeVariables()
328    {
329        if (null === $this->_variables) {
330            $this->_variables = new \ArrayObject();
331        }
332
333        return;
334    }
335}
336