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/*
* Copyright (C) 2012 Jamie Bullock
*
* 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.
*
*/
/** \file xtract_helper.h: helper functions for making life with libxtract a bit more bearable */
#ifndef XTRACT_HELPER_H
#define XTRACT_HELPER_H
#ifdef __cplusplus
extern "C" {
#endif
#ifdef _MSC_VER
#ifndef __cplusplus
typedef int bool;
#define false 0
#define true 1
#endif
#else
#include <stdbool.h>
#endif
/**
* \defgroup helper helper functions
*
* Declares helper functions, and their parameters.
*
* \note These functions don't necessarily conform to the prototype used in xtract_scalar.h and xtract_vector.h etc, and as such are intended to be called 'directly' rather than via the xtract[] function pointer array (libxtract.h)
*
* @{
*/
/** \brief Apply a window function to an array of length N
*
* \param *data a pointer to an array of doubles
* \param N the number of elements in the array pointed to by *data
* \param *argv a pointer to a window function as returned by xtract_make_window()
* \param *result a pointer to the first element an array containing the windowed data
*
* It is up to the caller to generate and free the array containing the window, and to allocate and free memory of size N to hold the data pointed to by *result
*
*/
int xtract_windowed(const double *data, const int N, const void *argv, double *result);
/** \brief Divides the array pointed to by *data into two subframes, and applies a given feature to each subframe, returning them in a single array pointed to by result
*
* \param *data an array of doubles
* \param N the number of elements in the array pointed by *data
* \param feature an integer representing the feature to be applied to each subframe in data. This will be a value as given in the enumeration xtract_features_ (libxtract.h)
* \param *argv a pointer to the argument vector to be passed to the feature extraction function as determined by feature
* \param *result a pointer to the 'packed' results of the feature calculation. This may be passed in as *data to xtract_features_from_subframes() to calculate further features on the subframes, or xtract_difference_vector(), to get the difference between the subframes.
*
*
* It is important to ensure that any _init_*() functions that are called in preparation for functions that are called on subframes are given the subframe size as 'N', and not the frame size. i.e. if xtract_features_from_subframes() is called with N=64, and feature=XTRACT_SPECTRUM, then xtract_init_fft() should be called with N=32.
*
*/
int xtract_features_from_subframes(const double *data, const int N, const int feature, const void *argv, double *result);
/** \brief Test whether a number is denormal */
int xtract_is_denormal(double const d);
/** \brief Test whether a number is a power of two */
bool xtract_is_poweroftwo(unsigned int x);
/** \brief Smooth a vector
*
* \param *data a pointer to an array of doubles
* \param N the number of elements in the array pointed to by *data to be smoothed
* \param *argv a pointer to a double giving the smoothing gain
* \param *result a pointer to the first element an array containing the smoothed data
*
* \note if passing in a spectrum e.g. *result from xtract_spectrum(), then N for xtract_smoothed() should be N / 2 with respect to the N for xtract_spectrum() so only amplitude components are smoothed, not frequencies!
*
*/
int xtract_smoothed(const double *data, const int N, const void *argv, double *result);
/** @} */
#ifdef __cplusplus
}
#endif
#endif
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