Repository: jerryscript-project/jerryscript
File: jerry-math/include/math.h (C/C++)

Code before:
/* Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef JERRY_MATH_H
#define JERRY_MATH_H

#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */

/* General Constants. */
#define INFINITY    (1e+300 * 1e+300) /* 1e+300*1e+300 must overflow */
#define NAN         (INFINITY * 0.0)
#define HUGE_VAL    INFINITY

#define isnan(x)    ((x) != (x))
#define isinf(x)    ((x) == INFINITY ? 1 : (x) == -INFINITY ? -1 : 0)
#define isfinite(x) (!isinf(x) && !isnan(x))

/* Exponential and Logarithmic constants. */
#define M_E        2.7182818284590452353602874713526625
#define M_SQRT2    1.4142135623730950488016887242096981
#define M_SQRT1_2  0.7071067811865475244008443621048490
#define M_LOG2E    1.4426950408889634073599246810018921
#define M_LOG10E   0.4342944819032518276511289189166051
#define M_LN2      0.6931471805599453094172321214581765
#define M_LN10     2.3025850929940456840179914546843642

/* Trigonometric Constants. */
#define M_PI       3.1415926535897932384626433832795029
#define M_PI_2     1.5707963267948966192313216916397514
#define M_PI_4     0.7853981633974483096156608458198757
#define M_1_PI     0.3183098861837906715377675267450287
#define M_2_PI     0.6366197723675813430755350534900574
#define M_2_SQRTPI 1.1283791670955125738961589031215452

/* Trigonometric functions. */
double cos (double);

Review comment (bug):
So, I did my homework. And it just turned out that (a) I did not know precisely how the standard specifies infinity and NaN, and (b) jerry-math's math.h was incorrect all along.

According to the specs:
- `INFINITY` and `NAN` are _float_ constant expressions, and
- `HUGE_VAL` is a _double_ constant expression (that evaluates to infinity).

Therefore, I suggest to have these macros as suggested _for the Windows/MSVC configuration_, but also keep a slightly updated version of the existing macros for other configs. That is:
```c
#ifdef _MSC_VER
#define INFINITY    ((float) (1e+300 * 1e+300))
#define NAN         ((float) (INFINITY * 0.0f))
#else
#define INFINITY    ((float) (1.0/0.0))
#define NAN         ((float) (0.0/0.0))
#endif
#define HUGE_VAL    ((double) INFINITY)
```


Code after:
/* Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef JERRY_MATH_H
#define JERRY_MATH_H

#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */

/* General Constants. */
#ifdef _MSC_VER
#define INFINITY    ((float) (1e+300 * 1e+300)) /* 1e+300*1e+300 must overflow */
#define NAN         ((float) (INFINITY * 0.0f))
#else /* !_MSC_VER */
#define INFINITY    ((float) (1.0 / 0.0))
#define NAN         ((float) (0.0 / 0.0))
#endif /* _MSC_VER */
#define HUGE_VAL    ((double) INFINITY)

#define isnan(x)    ((x) != (x))
#define isinf(x)    ((x) == INFINITY ? 1 : (x) == -INFINITY ? -1 : 0)
#define isfinite(x) (!isinf(x) && !isnan(x))

/* Exponential and Logarithmic constants. */
#define M_E        2.7182818284590452353602874713526625
#define M_SQRT2    1.4142135623730950488016887242096981
#define M_SQRT1_2  0.7071067811865475244008443621048490
#define M_LOG2E    1.4426950408889634073599246810018921
#define M_LOG10E   0.4342944819032518276511289189166051
#define M_LN2      0.6931471805599453094172321214581765
#define M_LN10     2.3025850929940456840179914546843642

/* Trigonometric Constants. */
#define M_PI       3.1415926535897932384626433832795029
#define M_PI_2     1.5707963267948966192313216916397514
#define M_PI_4     0.7853981633974483096156608458198757
#define M_1_PI     0.3183098861837906715377675267450287