libdspl-2.0/dspl/src/array/flipip.c

/*
* Copyright (c) 2015-2020 Sergey Bakhurin
* Digital Signal Processing Library [http://dsplib.org]
*
* This file is part of libdspl-2.0.
*
* is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser    General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DSPL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.    See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Foobar.    If not, see <http://www.gnu.org/licenses/>.
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dspl.h"



#ifdef DOXYGEN_ENGLISH
/*! ****************************************************************************
\ingroup ARRAY_GROUP
\fn int flipip(double* x, int n)
\brief
Flip real vector `x` in place

Function flips real vector `x` length `n` in the memory. \n
For example real vector `x` length 6:\n
\verbatim
x = [0, 1, 2, 3, 4, 5]
\endverbatim
After flipping it will be as follow:
\verbatim
x = [5, 4, 3, 2, 1, 0]
\endverbatim

\param[in, out] x
Pointer to the real vector `x`. \n
Vector size is `[n x 1]`. \n
Flipped vector will be on the same address. \n
\n

\param[in] n
Length of the vector `x`. \n
\n

\return
`RES_OK` if function returns successfully. \n
 Else \ref ERROR_CODE_GROUP "error code".

Example:
\code{.cpp}
double x[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
int i;
for(i = 0; i < 5; i++)
    printf("%6.1f    ", x[i]);
flipip(x, 5);
printf("\n");
for(i = 0; i < 5; i++)
    printf("%6.1f    ", x[i]);
\endcode
\n
Program result:
\verbatim
     0.0         1.0         2.0         3.0         4.0
     4.0         3.0         2.0         1.0         0.0
\endverbatim

\author Sergey Bakhurin www.dsplib.org
***************************************************************************** */
#endif
#ifdef DOXYGEN_RUSSIAN
/*! ****************************************************************************
\ingroup ARRAY_GROUP
\fn int flipip(double* x, int n)
\brief Функция отражения вещественного вектора `x`

Функция производит отражение вещественного вектора длины `n`
в памяти данных. \n
Например исходный вектор `x`    длины 6: \n
\verbatim
x = [0, 1, 2, 3, 4, 5]
\endverbatim
После отражения вектор `x` будет иметь вид:
\verbatim
x = [5, 4, 3, 2, 1, 0]
\endverbatim

\param[in, out] x
Указатель на вещественный вектор `x`. \n
Размер вектора `[n x 1]`. \n
Результат отражения будет помещен по этому же адресу. \n

\param[in] n
Размер вектора `x`. \n \n

\return
`RES_OK` если функция выполнена успешно. \n
В противном случае \ref ERROR_CODE_GROUP "код ошибки".

Пример:
\code{.cpp}
double x[5] = {0.0, 1.0, 2.0, 3.0, 4.0};
int i;
for(i = 0; i < 5; i++)
    printf("%6.1f    ", x[i]);
flipip(x, 5);
printf("\n");
for(i = 0; i < 5; i++)
    printf("%6.1f    ", x[i]);
\endcode
\n
Результат выполнения:
\verbatim
     0.0         1.0         2.0         3.0         4.0
     4.0         3.0         2.0         1.0         0.0
\endverbatim

\author
Бахурин Сергей
www.dsplib.org
***************************************************************************** */
#endif
int DSPL_API flipip(double* x, int n)
{
    int k;
    double tmp;
    if(!x)
        return ERROR_PTR;
    if(n<1)
        return ERROR_SIZE;

    for(k = 0; k < n/2; k++)
    {
        tmp = x[k];
        x[k] = x[n-1-k];
        x[n-1-k] = tmp;
    }
    return RES_OK;

}