commit ce36ca9ef5abab699353a7032c974e6872039339 Author: Laurence Withers Date: Mon Nov 8 15:18:07 2010 +0000 Import initial work diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..2156e01 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +obj +html +.*.swp diff --git a/COPYING b/COPYING new file mode 100644 index 0000000..94a9ed0 --- /dev/null +++ b/COPYING @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/README b/README new file mode 100644 index 0000000..4f79b99 --- /dev/null +++ b/README @@ -0,0 +1,24 @@ +libiir http://www.lwithers.me.uk/usr/src/libiir/ +======================================================================== +Copyright: ©2010, Laurence Withers. +Author: Laurence Withers +License: GPLv3 + +Original Butterworth IIR filter code, available under the exstrom/ +directory: + +Website: http://www.exstrom.com/journal/sigproc/ +Copyright: ©2007, Exstrom Laboratories LLC +License: GPLv2 or later + +Really Quick Instructions +------------------------- + +To build: ./make.sh +To install: ./make.sh install + +You might want to edit 'config' first. You might also want to set +'INSTALL_PREFIX', which is prepended onto the destination of any +installed file. + +See Doxygen documentation for details. diff --git a/config b/config new file mode 100644 index 0000000..f7f2910 --- /dev/null +++ b/config @@ -0,0 +1,36 @@ +# libiir/config +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# +# This file contains options used to build libiir. + + +# PREFIX is the most important option. Many other paths are derived from it, as follows: +# +# PREFIX | / | /usr | /usr/local | /opt/* +# ------------+-------------------+-------------------+-------------------+----------------- +# BINDIR | /bin | /usr/bin | /usr/local/bin | /opt/*/bin +# SBINDIR | /sbin | /usr/sbin | /usr/local/sbin | /opt/*/sbin +# LIBDIR | /lib | /usr/lib | /usr/local/lib | /opt/*/lib +# INCLUDEDIR | /usr/include | /usr/include | /usr/local/include| /opt/*/include +# CONFIGDIR | /etc | /etc | /usr/local/etc | /etc/opt/* +# VARDIR | /var | /var | /var | /var/opt/* +# SHAREDIR | /usr/share | /usr/share | /usr/local/share | /opt/*/share +# DOCSDIR | /usr/share/doc | /usr/share/doc | /usr/local/share/doc, /opt/*/doc +# WEBDIR | /srv/http | /srv/http | /srv/http | /opt/*/http +# +# Specific notes: +# When installing, all paths are prepended with INSTALL_PREFIX. +# Any parameter can be overridden by setting an environment variable. +# CGIDIR is set to ${WEBDIR}/cgi-bin . +# +[ -z "${PREFIX}" ] && PREFIX="/usr/local" +source "scripts/paths" + +# Project-specific variables below. +[ -z "${CC}" ] && CC="gcc" +[ -z "${CFLAGS}" ] && CFLAGS="-g -O2 -W -Wall" diff --git a/exstrom/iir.h b/exstrom/iir.h new file mode 100644 index 0000000..fd465d0 --- /dev/null +++ b/exstrom/iir.h @@ -0,0 +1,17 @@ +double *binomial_mult( int n, double *p ); +double *trinomial_mult( int n, double *b, double *c ); + +double *dcof_bwlp( int n, double fcf ); +double *dcof_bwhp( int n, double fcf ); +double *dcof_bwbp( int n, double f1f, double f2f ); +double *dcof_bwbs( int n, double f1f, double f2f ); + +int *ccof_bwlp( int n ); +int *ccof_bwhp( int n ); +int *ccof_bwbp( int n ); +double *ccof_bwbs( int n, double f1f, double f2f ); + +double sf_bwlp( int n, double fcf ); +double sf_bwhp( int n, double fcf ); +double sf_bwbp( int n, double f1f, double f2f ); +double sf_bwbs( int n, double f1f, double f2f ); diff --git a/exstrom/iir.txt b/exstrom/iir.txt new file mode 100644 index 0000000..f918b15 --- /dev/null +++ b/exstrom/iir.txt @@ -0,0 +1,264 @@ +IIR Digital Filter Functions +============================ + +An IIR filter is also known as a recursive digital filter because its output +is a function of previous outputs as well as the input. If x[n] represents the +nth input to the filter and y[n] is the nth output of the filter then a +general iir filter is implemented as follows: + +y[n] = c0*x[n] + c1*x[n-1] + ... + cM*x[n-M] - ( d1*y[n-1] + d2*y[n-2] + ... + dN*y[n-N]) + +This means that the nth output is a linear function of the nth input, the +previous M inputs, and the previous N outputs. The c and d coefficients are +calculated to give the filter a specific frequency response. The number of +coefficients, M and N, will vary depending on the type of filter. There are +many different kinds of iir filters and many different ways to calculate the +coefficients. Listed below are filter types (currently only Butterworth +filters) and the functions that can be used to calculate the c and d +coefficients for lowpass, highpass, bandpass, and bandstop implementations of +the filter. + +I. Butterworth Filters + ------------------- + + A Butterworth filter is also known as a maximally flat filter because its + frequency response is characterized by no ripple in the pass band and stop + band. + + A. Lowpass functions + + The example program that shows how to use all the lowpass functions is + bwlp. + + double *dcof_bwlp( int N, double fcf ); + + This fuction calculates the d coefficients for a Butterworth lowpass + filter. The coefficients are returned as an array of doubles. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + fcf = filter cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A pointer to an array of doubles is returned. The size of the + array is equal to N+1, one more than the filter order. The first + element of the array is d0, the coefficient of y[n], which will + always be equal to 1. The second element of the array is d1, the + coefficient of y[n-1], and so on. The calling program must free + the array when finished with it. + + + int *ccof_bwlp( int n ); + + This fuction calculates the c coefficients for a Butterworth lowpass + filter. The coefficients are returned as an array of integers. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + + Return value: + A pointer to an array of integers is returned. The size of the + array is equal to N+1, one more than the filter order. The first + element of the array is c0, the coefficient of x[n], which is the + current input to the filter. The second element of the array is + c1, the coefficient of x[n-1], and so on. The calling program + must free the array when finished with it. + + + double sf_bwlp( int n, double fcf ); + + This fuction calculates the scaling factor for a Butterworth lowpass + filter. The scaling factor is what the c coefficients must be + multiplied by so that the frequency response of the filter has a + maximum magnitude of 1. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + fcf = filter cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A double that is scaling factor. + + B. Highpass functions + + The example program that shows how to use all the highpass functions is + bwhp. + + double *dcof_bwhp( int N, double fcf ); + + This fuction calculates the d coefficients for a Butterworth highpass + filter. The coefficients are returned as an array of doubles. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + fcf = filter cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A pointer to an array of doubles is returned. The size of the + array is equal to N+1, one more than the filter order. The first + element of the array is d0, the coefficient of y[n], which will + always be equal to 1. The second element of the array is d1, the + coefficient of y[n-1], and so on. The calling program must free + the array when finished with it. + + + int *ccof_bwhp( int n ); + + This fuction calculates the c coefficients for a Butterworth highpass + filter. The coefficients are returned as an array of integers. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + + Return value: + A pointer to an array of integers is returned. The size of the + array is equal to N+1, one more than the filter order. The first + element of the array is c0, the coefficient of x[n], which is the + current input to the filter. The second element of the array is + c1, the coefficient of x[n-1], and so on. The calling program + must free the array when finished with it. + + + double sf_bwhp( int n, double fcf ); + + This fuction calculates the scaling factor for a Butterworth highpass + filter. The scaling factor is what the c coefficients must be + multiplied by so that the frequency response of the filter has a + maximum magnitude of 1. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + fcf = filter cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A double that is scaling factor. + + C. Bandpass functions + + The example program that shows how to use all the bandpass functions is + bwbp. + + double *dcof_bwbp( int n, double f1f, double f2f ); + + This fuction calculates the d coefficients for a Butterworth bandpass + filter. The coefficients are returned as an array of doubles. Note + that, although there is no upper limit on the filter order, if the + bandwidth, f2f - f1f, is very small, the coefficients returned may + not give the desired response due to numerical instability in the + calculation. This problem should not occure if the filter order is + kept less that or equal to 10. For very small bandwidths you should + always verify the frequency response using a program such as rffr. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + f1f = lower cutoff frequency as a fraction of pi. Range = [0,1]. + f2f = upper cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A pointer to an array of doubles is returned. The size of the + array is equal to 2N+1, one more than twice the filter order. The + first element of the array is d0, the coefficient of y[n], which + will always be equal to 1. The second element of the array is d1, + the coefficient of y[n-1], and so on. The calling program must + free the array when finished with it. + + + int *ccof_bwbp( int n ); + + This fuction calculates the c coefficients for a Butterworth bandpass + filter. The coefficients are returned as an array of integers. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + + Return value: + A pointer to an array of integers is returned. The size of the + array is equal to 2N+1, one more than twice the filter order. The + first element of the array is c0, the coefficient of x[n], which + is the current input to the filter. The second element of the + array is c1, the coefficient of x[n-1], and so on. The calling + program must free the array when finished with it. Note that ck + for all odd k, c1, c3, c5, and so on, will be equal to zero for + this filter. + + + double sf_bwbp( int n, double f1f, double f2f ); + + This fuction calculates the scaling factor for a Butterworth bandpass + filter. The scaling factor is what the c coefficients must be + multiplied by so that the frequency response of the filter has a + maximum magnitude of 1. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + f1f = lower cutoff frequency as a fraction of pi. Range = [0,1]. + f2f = upper cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A double that is scaling factor. + + D. Bandstop functions + + The example program that shows how to use all the bandstop functions is + bwbs. + + double *dcof_bwbs( int n, double f1f, double f2f ); + + This fuction calculates the d coefficients for a Butterworth bandstop + filter. The coefficients are returned as an array of doubles. Note + that, although there is no upper limit on the filter order, if the + bandwidth, f2f - f1f, is very small, the coefficients returned may + not give the desired response due to numerical instability in the + calculation. This problem should not occure if the filter order is + kept less that or equal to 10. For very small bandwidths you should + always verify the frequency response using a program such as rffr. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + f1f = lower cutoff frequency as a fraction of pi. Range = [0,1]. + f2f = upper cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A pointer to an array of doubles is returned. The size of the + array is equal to 2N+1, one more than twice the filter order. The + first element of the array is d0, the coefficient of y[n], which + will always be equal to 1. The second element of the array is d1, + the coefficient of y[n-1], and so on. The calling program must + free the array when finished with it. + + + double *ccof_bwbs( int n, double f1f, double f2f ); + + This fuction calculates the c coefficients for a Butterworth bandstop + filter. The coefficients are returned as an array of doubles. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + f1f = lower cutoff frequency as a fraction of pi. Range = [0,1]. + f2f = upper cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A pointer to an array of doubles is returned. The size of the + array is equal to 2N+1, one more than twice the filter order. The + first element of the array is c0, the coefficient of x[n], which + is the current input to the filter. The second element of the + array is c1, the coefficient of x[n-1], and so on. The calling + program must free the array when finished with it. Note that ck + for all odd k, c1, c3, c5, and so on, will be equal to zero for + this filter. + + + double sf_bwbs( int n, double f1f, double f2f ); + + This fuction calculates the scaling factor for a Butterworth bandstop + filter. The scaling factor is what the c coefficients must be + multiplied by so that the frequency response of the filter has a + maximum magnitude of 1. + + Parameters: + N = filter order. Range = [1, 20 or more] no fixed upper limit. + f1f = lower cutoff frequency as a fraction of pi. Range = [0,1]. + f2f = upper cutoff frequency as a fraction of pi. Range = [0,1]. + + Return value: + A double that is scaling factor. diff --git a/exstrom/liir.c b/exstrom/liir.c new file mode 100644 index 0000000..deba197 --- /dev/null +++ b/exstrom/liir.c @@ -0,0 +1,580 @@ +/* + * COPYRIGHT + * + * liir - Recursive digital filter functions + * Copyright (C) 2007 Exstrom Laboratories LLC + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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. + * + * A copy of the GNU General Public License is available on the internet at: + * + * http://www.gnu.org/copyleft/gpl.html + * + * or you can write to: + * + * The Free Software Foundation, Inc. + * 675 Mass Ave + * Cambridge, MA 02139, USA + * + * You can contact Exstrom Laboratories LLC via Email at: + * + * stefan(AT)exstrom.com + * + * or you can write to: + * + * Exstrom Laboratories LLC + * P.O. Box 7651 + * Longmont, CO 80501, USA + * + */ + +#include +#include +#include +#include +#include "iir.h" + +/********************************************************************** + binomial_mult - multiplies a series of binomials together and returns + the coefficients of the resulting polynomial. + + The multiplication has the following form: + + (x+p[0])*(x+p[1])*...*(x+p[n-1]) + + The p[i] coefficients are assumed to be complex and are passed to the + function as a pointer to an array of doubles of length 2n. + + The resulting polynomial has the following form: + + x^n + a[0]*x^n-1 + a[1]*x^n-2 + ... +a[n-2]*x + a[n-1] + + The a[i] coefficients can in general be complex but should in most + cases turn out to be real. The a[i] coefficients are returned by the + function as a pointer to an array of doubles of length 2n. Storage + for the array is allocated by the function and should be freed by the + calling program when no longer needed. + + Function arguments: + + n - The number of binomials to multiply + p - Pointer to an array of doubles where p[2i] (i=0...n-1) is + assumed to be the real part of the coefficient of the ith binomial + and p[2i+1] is assumed to be the imaginary part. The overall size + of the array is then 2n. +*/ + +double *binomial_mult( int n, double *p ) +{ + int i, j; + double *a; + + a = (double *)calloc( 2 * n, sizeof(double) ); + if( a == NULL ) return( NULL ); + + for( i = 0; i < n; ++i ) + { + for( j = i; j > 0; --j ) + { + a[2*j] += p[2*i] * a[2*(j-1)] - p[2*i+1] * a[2*(j-1)+1]; + a[2*j+1] += p[2*i] * a[2*(j-1)+1] + p[2*i+1] * a[2*(j-1)]; + } + a[0] += p[2*i]; + a[1] += p[2*i+1]; + } + return( a ); +} + + +/********************************************************************** + trinomial_mult - multiplies a series of trinomials together and returns + the coefficients of the resulting polynomial. + + The multiplication has the following form: + + (x^2 + b[0]x + c[0])*(x^2 + b[1]x + c[1])*...*(x^2 + b[n-1]x + c[n-1]) + + The b[i] and c[i] coefficients are assumed to be complex and are passed + to the function as a pointers to arrays of doubles of length 2n. The real + part of the coefficients are stored in the even numbered elements of the + array and the imaginary parts are stored in the odd numbered elements. + + The resulting polynomial has the following form: + + x^2n + a[0]*x^2n-1 + a[1]*x^2n-2 + ... +a[2n-2]*x + a[2n-1] + + The a[i] coefficients can in general be complex but should in most cases + turn out to be real. The a[i] coefficients are returned by the function as + a pointer to an array of doubles of length 4n. The real and imaginary + parts are stored, respectively, in the even and odd elements of the array. + Storage for the array is allocated by the function and should be freed by + the calling program when no longer needed. + + Function arguments: + + n - The number of trinomials to multiply + b - Pointer to an array of doubles of length 2n. + c - Pointer to an array of doubles of length 2n. +*/ + +double *trinomial_mult( int n, double *b, double *c ) +{ + int i, j; + double *a; + + a = (double *)calloc( 4 * n, sizeof(double) ); + if( a == NULL ) return( NULL ); + + a[2] = c[0]; + a[3] = c[1]; + a[0] = b[0]; + a[1] = b[1]; + + for( i = 1; i < n; ++i ) + { + a[2*(2*i+1)] += c[2*i]*a[2*(2*i-1)] - c[2*i+1]*a[2*(2*i-1)+1]; + a[2*(2*i+1)+1] += c[2*i]*a[2*(2*i-1)+1] + c[2*i+1]*a[2*(2*i-1)]; + + for( j = 2*i; j > 1; --j ) + { + a[2*j] += b[2*i] * a[2*(j-1)] - b[2*i+1] * a[2*(j-1)+1] + + c[2*i] * a[2*(j-2)] - c[2*i+1] * a[2*(j-2)+1]; + a[2*j+1] += b[2*i] * a[2*(j-1)+1] + b[2*i+1] * a[2*(j-1)] + + c[2*i] * a[2*(j-2)+1] + c[2*i+1] * a[2*(j-2)]; + } + + a[2] += b[2*i] * a[0] - b[2*i+1] * a[1] + c[2*i]; + a[3] += b[2*i] * a[1] + b[2*i+1] * a[0] + c[2*i+1]; + a[0] += b[2*i]; + a[1] += b[2*i+1]; + } + + return( a ); +} + + +/********************************************************************** + dcof_bwlp - calculates the d coefficients for a butterworth lowpass + filter. The coefficients are returned as an array of doubles. + +*/ + +double *dcof_bwlp( int n, double fcf ) +{ + int k; // loop variables + double theta; // M_PI * fcf / 2.0 + double st; // sine of theta + double ct; // cosine of theta + double parg; // pole angle + double sparg; // sine of the pole angle + double cparg; // cosine of the pole angle + double a; // workspace variable + double *rcof; // binomial coefficients + double *dcof; // dk coefficients + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + if( rcof == NULL ) return( NULL ); + + theta = M_PI * fcf; + st = sin(theta); + ct = cos(theta); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + st*sparg; + rcof[2*k] = -ct/a; + rcof[2*k+1] = -st*cparg/a; + } + + dcof = binomial_mult( n, rcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + dcof_bwhp - calculates the d coefficients for a butterworth highpass + filter. The coefficients are returned as an array of doubles. + +*/ + +double *dcof_bwhp( int n, double fcf ) +{ + return( dcof_bwlp( n, fcf ) ); +} + + +/********************************************************************** + dcof_bwbp - calculates the d coefficients for a butterworth bandpass + filter. The coefficients are returned as an array of doubles. + +*/ + +double *dcof_bwbp( int n, double f1f, double f2f ) +{ + int k; // loop variables + double theta; // M_PI * (f2f - f1f) / 2.0 + double cp; // cosine of phi + double st; // sine of theta + double ct; // cosine of theta + double s2t; // sine of 2*theta + double c2t; // cosine 0f 2*theta + double *rcof; // z^-2 coefficients + double *tcof; // z^-1 coefficients + double *dcof; // dk coefficients + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a; // workspace variables + + cp = cos(M_PI * (f2f + f1f) / 2.0); + theta = M_PI * (f2f - f1f) / 2.0; + st = sin(theta); + ct = cos(theta); + s2t = 2.0*st*ct; // sine of 2*theta + c2t = 2.0*ct*ct - 1.0; // cosine of 2*theta + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + tcof = (double *)calloc( 2 * n, sizeof(double) ); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + s2t*sparg; + rcof[2*k] = c2t/a; + rcof[2*k+1] = s2t*cparg/a; + tcof[2*k] = -2.0*cp*(ct+st*sparg)/a; + tcof[2*k+1] = -2.0*cp*st*cparg/a; + } + + dcof = trinomial_mult( n, tcof, rcof ); + free( tcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= 2*n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + dcof_bwbs - calculates the d coefficients for a butterworth bandstop + filter. The coefficients are returned as an array of doubles. + +*/ + +double *dcof_bwbs( int n, double f1f, double f2f ) +{ + int k; // loop variables + double theta; // M_PI * (f2f - f1f) / 2.0 + double cp; // cosine of phi + double st; // sine of theta + double ct; // cosine of theta + double s2t; // sine of 2*theta + double c2t; // cosine 0f 2*theta + double *rcof; // z^-2 coefficients + double *tcof; // z^-1 coefficients + double *dcof; // dk coefficients + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a; // workspace variables + + cp = cos(M_PI * (f2f + f1f) / 2.0); + theta = M_PI * (f2f - f1f) / 2.0; + st = sin(theta); + ct = cos(theta); + s2t = 2.0*st*ct; // sine of 2*theta + c2t = 2.0*ct*ct - 1.0; // cosine 0f 2*theta + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + tcof = (double *)calloc( 2 * n, sizeof(double) ); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + s2t*sparg; + rcof[2*k] = c2t/a; + rcof[2*k+1] = -s2t*cparg/a; + tcof[2*k] = -2.0*cp*(ct+st*sparg)/a; + tcof[2*k+1] = 2.0*cp*st*cparg/a; + } + + dcof = trinomial_mult( n, tcof, rcof ); + free( tcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= 2*n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + ccof_bwlp - calculates the c coefficients for a butterworth lowpass + filter. The coefficients are returned as an array of integers. + +*/ + +int *ccof_bwlp( int n ) +{ + int *ccof; + int m; + int i; + + ccof = (int *)calloc( n+1, sizeof(int) ); + if( ccof == NULL ) return( NULL ); + + ccof[0] = 1; + ccof[1] = n; + m = n/2; + for( i=2; i <= m; ++i) + { + ccof[i] = (n-i+1)*ccof[i-1]/i; + ccof[n-i]= ccof[i]; + } + ccof[n-1] = n; + ccof[n] = 1; + + return( ccof ); +} + +/********************************************************************** + ccof_bwhp - calculates the c coefficients for a butterworth highpass + filter. The coefficients are returned as an array of integers. + +*/ + +int *ccof_bwhp( int n ) +{ + int *ccof; + int i; + + ccof = ccof_bwlp( n ); + if( ccof == NULL ) return( NULL ); + + for( i = 0; i <= n; ++i) + if( i % 2 ) ccof[i] = -ccof[i]; + + return( ccof ); +} + +/********************************************************************** + ccof_bwbp - calculates the c coefficients for a butterworth bandpass + filter. The coefficients are returned as an array of integers. + +*/ + +int *ccof_bwbp( int n ) +{ + int *tcof; + int *ccof; + int i; + + ccof = (int *)calloc( 2*n+1, sizeof(int) ); + if( ccof == NULL ) return( NULL ); + + tcof = ccof_bwhp(n); + if( tcof == NULL ) return( NULL ); + + for( i = 0; i < n; ++i) + { + ccof[2*i] = tcof[i]; + ccof[2*i+1] = 0.0; + } + ccof[2*n] = tcof[n]; + + free( tcof ); + return( ccof ); +} + +/********************************************************************** + ccof_bwbs - calculates the c coefficients for a butterworth bandstop + filter. The coefficients are returned as an array of integers. + +*/ + +double *ccof_bwbs( int n, double f1f, double f2f ) +{ + double alpha; + double *ccof; + int i, j; + + alpha = -2.0 * cos(M_PI * (f2f + f1f) / 2.0) / cos(M_PI * (f2f - f1f) / 2.0); + + ccof = (double *)calloc( 2*n+1, sizeof(double) ); + + ccof[0] = 1.0; + + ccof[2] = 1.0; + ccof[1] = alpha; + + for( i = 1; i < n; ++i ) + { + ccof[2*i+2] += ccof[2*i]; + for( j = 2*i; j > 1; --j ) + ccof[j+1] += alpha * ccof[j] + ccof[j-1]; + + ccof[2] += alpha * ccof[1] + 1.0; + ccof[1] += alpha; + } + + return( ccof ); +} + +/********************************************************************** + sf_bwlp - calculates the scaling factor for a butterworth lowpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +double sf_bwlp( int n, double fcf ) +{ + int m, k; // loop variables + double omega; // M_PI * fcf + double fomega; // function of omega + double parg0; // zeroth pole angle + double sf; // scaling factor + + omega = M_PI * fcf; + fomega = sin(omega); + parg0 = M_PI / (double)(2*n); + + m = n / 2; + sf = 1.0; + for( k = 0; k < n/2; ++k ) + sf *= 1.0 + fomega * sin((double)(2*k+1)*parg0); + + fomega = sin(omega / 2.0); + + if( n % 2 ) sf *= fomega + cos(omega / 2.0); + sf = pow( fomega, n ) / sf; + + return(sf); +} + +/********************************************************************** + sf_bwhp - calculates the scaling factor for a butterworth highpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +double sf_bwhp( int n, double fcf ) +{ + int m, k; // loop variables + double omega; // M_PI * fcf + double fomega; // function of omega + double parg0; // zeroth pole angle + double sf; // scaling factor + + omega = M_PI * fcf; + fomega = sin(omega); + parg0 = M_PI / (double)(2*n); + + m = n / 2; + sf = 1.0; + for( k = 0; k < n/2; ++k ) + sf *= 1.0 + fomega * sin((double)(2*k+1)*parg0); + + fomega = cos(omega / 2.0); + + if( n % 2 ) sf *= fomega + sin(omega / 2.0); + sf = pow( fomega, n ) / sf; + + return(sf); +} + +/********************************************************************** + sf_bwbp - calculates the scaling factor for a butterworth bandpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +double sf_bwbp( int n, double f1f, double f2f ) +{ + int k; // loop variables + double ctt; // cotangent of theta + double sfr, sfi; // real and imaginary parts of the scaling factor + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a, b, c; // workspace variables + + ctt = 1.0 / tan(M_PI * (f2f - f1f) / 2.0); + sfr = 1.0; + sfi = 0.0; + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = ctt + sin(parg); + cparg = cos(parg); + a = (sfr + sfi)*(sparg - cparg); + b = sfr * sparg; + c = -sfi * cparg; + sfr = b - c; + sfi = a - b - c; + } + + return( 1.0 / sfr ); +} + +/********************************************************************** + sf_bwbs - calculates the scaling factor for a butterworth bandstop filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +double sf_bwbs( int n, double f1f, double f2f ) +{ + int k; // loop variables + double tt; // tangent of theta + double sfr, sfi; // real and imaginary parts of the scaling factor + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a, b, c; // workspace variables + + tt = tan(M_PI * (f2f - f1f) / 2.0); + sfr = 1.0; + sfi = 0.0; + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = tt + sin(parg); + cparg = cos(parg); + a = (sfr + sfi)*(sparg - cparg); + b = sfr * sparg; + c = -sfi * cparg; + sfr = b - c; + sfi = a - b - c; + } + + return( 1.0 / sfr ); +} diff --git a/make.sh b/make.sh new file mode 100755 index 0000000..174b746 --- /dev/null +++ b/make.sh @@ -0,0 +1,296 @@ +#!/bin/bash +# libiir/make.sh +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# + + +# This file is the script used to build libiir. There are some +# options that can be edited; these are set in the file 'config' (or you +# can pass them in as environment variables). +if [ ! -e "config" ] +then + echo "Configuration file not found???" + exit 1 +fi +source "./config" # don't fail on error, since last command in config might return false + + + +# Get version information +source "./version" || exit 1 +VERSION="${VERMAJOR}.${VERMINOR}.${VERMICRO}" + + + +# Get standard functions +[ -z "${VERBOSE}" ] && VERBOSE="0" +source "./scripts/functions.sh" || exit 1 + + +# List of directories which will be emptied by clean. +OUTPUT_DIRS="obj html" + + + +# This function makes a monolithic file out of several source files. Its +# first argument is the name of the output file, and the second is the +# format of monolithic file to create (for example, "C" will cause the +# inclusion of "#line" directives at the top of each included file). +# +# It also examines the following variables: +# MONOLITHIC_TESTS if any file mentioned in this list is newer +# than the output file, then we recreate it +# MONOLITHIC_SOURCE a list (in order) of the source files +# MONOLITHIC_OPTIONS will #define the options to match the respective +# environment variables. +# +# Recognised formats are: +# none no special processing happens before each file +# C #line directives are inserted before each file +# and VERSION, VERMAJOR etc. are #defined +# Ch Like C, but for header files (no VERSION #defines) +# +make_monolithic() { + if [ $# -ne 2 ] + then + print_failure "make_monolithic() called with wrong number of arguments" + print_failure "(expecting 2, got $#)" + return 1 + fi + + MONOLITHIC_OUT=$1 + + # extract options + HASHLINE=0 + VERDEFINE=0 + HASHDEFINE=0 + if [ "$2" == "C" ] + then + HASHLINE=1 + VERDEFINE=1 + HASHDEFINE=1 + elif [ "$2" == "Ch" ] + then + HASHLINE=1 + HASHDEFINE=1 + elif [ "$2" == "none" ] + then + HASHLINE=0 # dummy command + else + print_failure "make_monolithic() called with unknown format $2" + return 1 + fi + + echo " Building monolithic file '${MONOLITHIC_OUT}'..." + + MODIFIED=0 + for FILE in ${MONOLITHIC_TESTS} ${MONOLITHIC_SOURCE} + do + if [ ! -e "${FILE}" ] + then + print_failure "'${FILE}' does not exist" + return 1 + fi + + if [ "${FILE}" -nt ${MONOLITHIC_OUT} ] + then + MODIFIED=1 + break + fi + done + + if [ ${MODIFIED} -ne 0 ] + then + do_cmd mkdir -p $(dirname ${MONOLITHIC_OUT}) + do_cmd rm -f ${MONOLITHIC_OUT} || exit 1 + + if [ ${VERDEFINE} -ne 0 ] + then + do_cmd_redir ${MONOLITHIC_OUT} echo "#define VERSION \"${VERSION}\"" || return 1 + do_cmd_redir ${MONOLITHIC_OUT} echo "#define VERMAJOR ${VERMAJOR}" || return 1 + do_cmd_redir ${MONOLITHIC_OUT} echo "#define VERMINOR ${VERMINOR}" || return 1 + do_cmd_redir ${MONOLITHIC_OUT} echo "#define VERMICRO ${VERMICRO}" || return 1 + do_cmd_redir ${MONOLITHIC_OUT} echo "#define VEREXTRA \"${VEREXTRA}\"" || return 1 + fi + + if [ ${HASHDEFINE} -ne 0 ] + then + for opt in ${MONOLITHIC_OPTIONS} + do + do_cmd_redir ${MONOLITHIC_OUT} echo "#define ${opt} ${!opt}" || return 1 + done + fi + + for FILE in ${MONOLITHIC_SOURCE} + do + if [ ${HASHLINE} -ne 0 ] + then + do_cmd_redir ${MONOLITHIC_OUT} echo "#line 1 \"${FILE}\"" || return 1 + fi + do_cmd_redir ${MONOLITHIC_OUT} cat "${FILE}" || return 1 + done + print_success "Done" + else + print_success "Up to date" + fi +} + + + +# This will build a directory tree, if required, with mode 0755. The +# argument is the directory to build. +build_dir_tree() { + # sanity check + if [ $# -ne 1 ] + then + print_failure "build_dir_tree() called with wrong number of arguments" + print_failure "(expecting 1, got $#)" + return 1 + fi + + build_dir_tree_recurse "${INSTALL_PREFIX}$1" +} + +build_dir_tree_recurse() { + local DIR="$1" + + # if the directory already exists, return success + [ -d "${DIR}" ] && return 0 + + # if something with this name already exists, but not a directory, + # then fail + if [ -e "${DIR}" ] + then + print_failure "Failed to create directory '${DIR}'" + return 1 + fi + + # build the directory, but if it fails, recurse a level (and handle + # the case where recursion fails) + mkdir "${DIR}" >& /dev/null + if [ $? -ne 0 ] + then + build_dir_tree_recurse $(dirname "${DIR}") || return 1 + echo " Creating directory '${DIR}'" + do_cmd mkdir "${DIR}" + if [ $? -ne 0 ] + then + print_failure "Failed to create directory '${DIR}'" + return 1 + fi + fi + + # set permissions on newly-created dir and return + chmod 0755 "${DIR}" + return 0 +} + + + +# This will install a file. The first parameter is the source, and the +# second is the destination. The third is the octal mode. +install_file() { + # figure out if $2 is a directory or not + DEST_FILE="${INSTALL_PREFIX}$2" + [ -d "${DEST_FILE}" ] && DEST_FILE="${INSTALL_PREFIX}$2/$(basename $1)" + + echo " Installing: '$1' -> '${DEST_FILE}'" + do_cmd cp -fP "$1" "${DEST_FILE}" || return 1 + do_cmd chmod "$3" "${DEST_FILE}" || return 1 + + return 0 +} + + + +# This will install a header file. It is basically similar to +# install_file(), only we strip out the #line directives. +install_header() { + DEST_FILE="${INSTALL_PREFIX}$2" + [ -d "${DEST_FILE}" ] && DEST_FILE="${INSTALL_PREFIX}$2/$(basename $1)" + + echo " Installing: '$1' -> '${DEST_FILE}'" + do_cmd rm -f ${DEST_FILE} || exit 1 + do_cmd_redir ${DEST_FILE} sed -e "s,^#line.*,," $1 || exit 1 + do_cmd chmod "$3" "${DEST_FILE}" || return 1 + + return 0 +} + + + +# This installs a symlink. The first argument is the symlink's name; the +# second the symlink's source filename, and the third is the directory +# in which to create the symlink. +install_symlink() { + echo " Installing symlink: '${INSTALL_PREFIX}$3/$1' -> '$2'" + + ( do_cmd ln -sf $2 ${INSTALL_PREFIX}$3/$1 ) || return 1 + + return 0 +} + + + +build_target() { + ITEMS="src/$1/build.default" + if [ ! -e "${ITEMS}" ] + then + ITEMS="$(find src -type f -name build.$1)" + fi + + if [ -z "${ITEMS}" ] + then + print_failure "Unrecognised target '$1'" + return 1 + fi + + for item in ${ITEMS} + do + do_cmd source ${item} || exit 1 + done + return 0 +} + + + +######################################################################## +# Main script +######################################################################## + +if [ $# -eq 0 ] +then + targets="default" +else + targets="$@" +fi + +for func in ${targets} +do + case ${func} in + clean) + echo "Cleaning..." + rm -rf ${OUTPUT_DIRS} + print_success "Done" + true + ;; + + # bad Kdevelop! bad! + -j1) + ;; + -k) + ;; + + *) + build_target ${func} || exit 1 + ;; + esac +done + +exit 0 + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: expandtab:ts=4:sw=4 diff --git a/run-test.sh b/run-test.sh new file mode 100755 index 0000000..b18a468 --- /dev/null +++ b/run-test.sh @@ -0,0 +1,54 @@ +#!/bin/bash +# libiir/test.sh +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# + +# Running this script on its own will display a summary of all the +# available tests; running it with arguments runs the relevant test. + + + +# This runs a test, setting the correct library path. +run_test() { + EXE=obj/tests/$1 + shift + if [ ! -x ${EXE} ] + then + echo "No such test '${EXE}'" + return 1 + fi + + LD_LIBRARY_PATH="obj:${LD_LIBRARY_PATH}" "${EXE}" "$@" || return 1 + return 0 +} + + + +# This prints summary output from each test app. +print_tests() { + echo "Available tests" + echo "---------------------------------------------------------------------" + for EXE in obj/tests/* + do + [ -x "${EXE}" ] || continue + NAME="$(echo "${EXE}" | sed 's,obj/tests/,,')" + echo -ne "${NAME}\t" + LD_LIBRARY_PATH="obj:${LD_LIBRARY_PATH}" "${EXE}" --print-summary + done +} + + +# Main script +if [ $# -eq 0 ] +then + print_tests + exit 0 +fi + +run_test $* + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: expandtab:ts=4:sw=4 diff --git a/scripts/.gitignore b/scripts/.gitignore new file mode 100644 index 0000000..edcbbeb --- /dev/null +++ b/scripts/.gitignore @@ -0,0 +1,20 @@ +build.app.c +build.app.c++ +build.app.c++-qt +build.app.sh +build.docs.doxygen +build.docs.none +build.files.none +build.firmware.gpasm +build.firmware.sdcc +build.lib.c +build.lib.c++ +build.make.none +build.module.c +build.tests.c +build.tests.c++ + +config-printflags.sh +module-create.sh +release.sh +version.sh diff --git a/scripts/functions.sh b/scripts/functions.sh new file mode 100644 index 0000000..29cc196 --- /dev/null +++ b/scripts/functions.sh @@ -0,0 +1,67 @@ +# libiir/scripts/functions.sh +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# + +# Common functions + + + +# Print a success message +print_success() { + if [ -z "${TERM}" -o "${TERM}" == "dumb" ] + then + echo -n " - " + else + (echo -n -e " \E[32m* "; tput sgr0) + fi + echo $* +} + + + +# Print a failure message +print_failure() { + if [ -z "${TERM}" -o "${TERM}" == "dumb" ] + then + echo -n " *** " + else + (echo -n -e " \E[31m*** "; tput sgr0) + fi + echo $* +} + + + +# This function carries out a command, but reports its failure if +# necessary. +do_cmd() { + [ "${VERBOSE}" != "0" ] && echo "$@" + "$@" + if [ $? -ne 0 ] + then + print_failure "'$@' failed." + return 1 + fi +} + + + +# This function carries out a command, but reports its failure if +# necessary. +do_cmd_redir() { + DEST=$1 + shift + [ "${VERBOSE}" != "0" ] && echo "$@ >> ${DEST}" + "$@" >> ${DEST} + if [ $? -ne 0 ] + then + print_failure "'$@' failed." + return 1 + fi +} + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: expandtab:ts=4:sw=4 diff --git a/scripts/paths b/scripts/paths new file mode 100644 index 0000000..43109bb --- /dev/null +++ b/scripts/paths @@ -0,0 +1,64 @@ +# libiir/scripts/paths +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# +# Default path setup. Not meant for editing; use environment variables +# to override values if needed. +# + +MY_PREFIX="${PREFIX}" +[ "${MY_PREFIX}" == "/" ] && MY_PREFIX="" + +[ -z "${BINDIR}" ] && BINDIR="${PREFIX}/bin" +[ -z "${SBINDIR}" ] && SBINDIR="${PREFIX}/sbin" +[ -z "${LIBDIR}" ] && LIBDIR="${PREFIX}/lib" + +if [ -z "${INCLUDEDIR}" ] +then + case "${PREFIX}" in + /) INCLUDEDIR="/usr/include" ;; + *) INCLUDEDIR="${PREFIX}/include" ;; + esac +fi + +if [ -z "${CONFIGDIR}" ] +then + case "${PREFIX}" in + / | /usr) CONFIGDIR="/etc" ;; + /opt*) CONFIGDIR="/etc${PREFIX}" ;; + *) CONFIGDIR="${PREFIX}/etc" ;; + esac +fi + +if [ -z "${VARDIR}" ] +then + case "${PREFIX}" in + / | /usr | /usr/local) VARDIR="/var" ;; + /opt*) VARDIR="/var${PREFIX}" ;; + *) VARDIR="${PREFIX}/var" ;; + esac +fi + +if [ -z "${SHAREDIR}" ] +then + case "${PREFIX}" in + /) SHAREDIR="/usr/share" ;; + *) SHAREDIR="${PREFIX}/share" ;; + esac +fi +[ -z "${DOCSDIR}" ] && DOCSDIR="${SHAREDIR}/doc" + +if [ -z "${SRVDIR}" ] +then + case "${PREFIX}" in + / | /usr | /usr/local) SRVDIR="/srv" ;; + *) SRVDIR="${PREFIX}/srv" ;; + esac +fi +[ -z "${WEBDIR}" ] && WEBDIR="${SRVDIR}/http" +[ -z "${CGIDIR}" ] && CGIDIR="${WEBDIR}/cgi-bin" + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/docs/.params b/src/docs/.params new file mode 100644 index 0000000..30ca609 --- /dev/null +++ b/src/docs/.params @@ -0,0 +1 @@ +docs doxygen docs diff --git a/src/docs/Doxyfile.in b/src/docs/Doxyfile.in new file mode 100644 index 0000000..b8624f3 --- /dev/null +++ b/src/docs/Doxyfile.in @@ -0,0 +1,207 @@ +# libiir/src/docs/Doxyfile.in +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# + +DOXYFILE_ENCODING = UTF-8 +PROJECT_NAME = libiir +OUTPUT_DIRECTORY = +CREATE_SUBDIRS = NO +OUTPUT_LANGUAGE = English +BRIEF_MEMBER_DESC = YES +REPEAT_BRIEF = YES +ABBREVIATE_BRIEF = +ALWAYS_DETAILED_SEC = NO +INLINE_INHERITED_MEMB = YES +FULL_PATH_NAMES = NO +STRIP_FROM_PATH = +STRIP_FROM_INC_PATH = +SHORT_NAMES = NO +JAVADOC_AUTOBRIEF = NO +QT_AUTOBRIEF = NO +MULTILINE_CPP_IS_BRIEF = YES +INHERIT_DOCS = YES +SEPARATE_MEMBER_PAGES = NO +TAB_SIZE = 4 +ALIASES = +OPTIMIZE_OUTPUT_FOR_C = YES +OPTIMIZE_OUTPUT_JAVA = NO +OPTIMIZE_FOR_FORTRAN = NO +OPTIMIZE_OUTPUT_VHDL = NO +BUILTIN_STL_SUPPORT = NO +CPP_CLI_SUPPORT = NO +SIP_SUPPORT = NO +IDL_PROPERTY_SUPPORT = NO +DISTRIBUTE_GROUP_DOC = NO +SUBGROUPING = YES +TYPEDEF_HIDES_STRUCT = NO +SYMBOL_CACHE_SIZE = 0 +EXTRACT_ALL = NO +EXTRACT_PRIVATE = NO +EXTRACT_STATIC = NO +EXTRACT_LOCAL_CLASSES = NO +EXTRACT_LOCAL_METHODS = NO +EXTRACT_ANON_NSPACES = NO +HIDE_UNDOC_MEMBERS = NO +HIDE_UNDOC_CLASSES = NO +HIDE_FRIEND_COMPOUNDS = YES +HIDE_IN_BODY_DOCS = NO +INTERNAL_DOCS = NO +CASE_SENSE_NAMES = YES +HIDE_SCOPE_NAMES = NO +SHOW_INCLUDE_FILES = NO +INLINE_INFO = YES +SORT_MEMBER_DOCS = NO +SORT_BRIEF_DOCS = NO +SORT_GROUP_NAMES = NO +SORT_BY_SCOPE_NAME = NO +GENERATE_TODOLIST = YES +GENERATE_TESTLIST = YES +GENERATE_BUGLIST = YES +GENERATE_DEPRECATEDLIST= YES +ENABLED_SECTIONS = +MAX_INITIALIZER_LINES = 30 +SHOW_USED_FILES = NO +SHOW_DIRECTORIES = NO +SHOW_FILES = NO +SHOW_NAMESPACES = YES +FILE_VERSION_FILTER = +LAYOUT_FILE = +QUIET = YES +WARNINGS = YES +WARN_IF_UNDOCUMENTED = YES +WARN_IF_DOC_ERROR = YES +WARN_NO_PARAMDOC = YES +WARN_FORMAT = "$file:$line: $text" +WARN_LOGFILE = +INPUT = +INPUT_ENCODING = UTF-8 +FILE_PATTERNS = +RECURSIVE = NO +EXCLUDE = +EXCLUDE_SYMLINKS = NO +EXCLUDE_PATTERNS = +EXCLUDE_SYMBOLS = +EXAMPLE_PATH = +EXAMPLE_PATTERNS = +EXAMPLE_RECURSIVE = NO +IMAGE_PATH = src/docs +INPUT_FILTER = +FILTER_PATTERNS = +FILTER_SOURCE_FILES = NO +SOURCE_BROWSER = NO +INLINE_SOURCES = NO +STRIP_CODE_COMMENTS = YES +REFERENCED_BY_RELATION = YES +REFERENCES_RELATION = YES +REFERENCES_LINK_SOURCE = YES +USE_HTAGS = NO +VERBATIM_HEADERS = NO +ALPHABETICAL_INDEX = YES +COLS_IN_ALPHA_INDEX = 5 +IGNORE_PREFIX = +GENERATE_HTML = YES +HTML_OUTPUT = html +HTML_FILE_EXTENSION = .html +HTML_HEADER = +HTML_FOOTER = +HTML_STYLESHEET = +HTML_ALIGN_MEMBERS = YES +HTML_DYNAMIC_SECTIONS = YES +GENERATE_DOCSET = NO +DOCSET_FEEDNAME = "Doxygen generated docs" +DOCSET_BUNDLE_ID = org.doxygen.Project +GENERATE_HTMLHELP = NO +CHM_FILE = +HHC_LOCATION = +GENERATE_CHI = NO +CHM_INDEX_ENCODING = +BINARY_TOC = NO +TOC_EXPAND = NO +GENERATE_QHP = NO +QCH_FILE = +QHP_NAMESPACE = org.doxygen.Project +QHP_VIRTUAL_FOLDER = doc +QHG_LOCATION = +DISABLE_INDEX = NO +ENUM_VALUES_PER_LINE = 4 +GENERATE_TREEVIEW = NO +TREEVIEW_WIDTH = 250 +FORMULA_FONTSIZE = 10 +GENERATE_LATEX = NO +LATEX_OUTPUT = latex +LATEX_CMD_NAME = latex +MAKEINDEX_CMD_NAME = makeindex +COMPACT_LATEX = NO +PAPER_TYPE = a4wide +EXTRA_PACKAGES = +LATEX_HEADER = +PDF_HYPERLINKS = NO +USE_PDFLATEX = NO +LATEX_BATCHMODE = NO +LATEX_HIDE_INDICES = NO +GENERATE_RTF = NO +RTF_OUTPUT = rtf +COMPACT_RTF = NO +RTF_HYPERLINKS = NO +RTF_STYLESHEET_FILE = +RTF_EXTENSIONS_FILE = +GENERATE_MAN = NO +MAN_OUTPUT = man +MAN_EXTENSION = .3 +MAN_LINKS = NO +GENERATE_XML = NO +XML_OUTPUT = xml +XML_SCHEMA = +XML_DTD = +XML_PROGRAMLISTING = YES +GENERATE_AUTOGEN_DEF = NO +GENERATE_PERLMOD = NO +PERLMOD_LATEX = NO +PERLMOD_PRETTY = YES +PERLMOD_MAKEVAR_PREFIX = +ENABLE_PREPROCESSING = YES +MACRO_EXPANSION = YES +EXPAND_ONLY_PREDEF = YES +SEARCH_INCLUDES = YES +INCLUDE_PATH = +INCLUDE_FILE_PATTERNS = +PREDEFINED = DOXYGEN \ + __attribute__()= +EXPAND_AS_DEFINED = +SKIP_FUNCTION_MACROS = YES +TAGFILES = +GENERATE_TAGFILE = +ALLEXTERNALS = NO +EXTERNAL_GROUPS = YES +PERL_PATH = /usr/bin/perl +CLASS_DIAGRAMS = YES +MSCGEN_PATH = +HIDE_UNDOC_RELATIONS = YES +HAVE_DOT = YES +DOT_FONTNAME = FreeSans +DOT_FONTSIZE = 10 +DOT_FONTPATH = +CLASS_GRAPH = YES +COLLABORATION_GRAPH = YES +GROUP_GRAPHS = NO +UML_LOOK = NO +TEMPLATE_RELATIONS = NO +INCLUDE_GRAPH = NO +INCLUDED_BY_GRAPH = NO +CALL_GRAPH = NO +CALLER_GRAPH = NO +GRAPHICAL_HIERARCHY = YES +DIRECTORY_GRAPH = NO +DOT_IMAGE_FORMAT = png +DOT_PATH = +DOTFILE_DIRS = +DOT_GRAPH_MAX_NODES = 50 +MAX_DOT_GRAPH_DEPTH = 0 +DOT_TRANSPARENT = YES +DOT_MULTI_TARGETS = YES +GENERATE_LEGEND = YES +DOT_CLEANUP = YES +SEARCHENGINE = NO diff --git a/src/docs/MainPage.dox b/src/docs/MainPage.dox new file mode 100644 index 0000000..f915aae --- /dev/null +++ b/src/docs/MainPage.dox @@ -0,0 +1,55 @@ +/* libiir/src/docs/MainPage.dox + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +/*! \mainpage + +This library allows the implementation of arbitrary IIR filters in C. It has +functions for generating and manipulating filters in terms of coefficients, for +chaining arbitrary filters together, and for generating coefficients for some +common types of filter. See \ref iir_structure for a definition of the IIR +filter equation. + +\section creation Filter creation + +At a high level, filters may be specified as strings. See \ref string_desc for +the required format and \ref iir_parse() for a C function returning a filter +instance from such a string. + +Otherwise, the library user must first create a set of coefficients using +\ref iir_coeff_new(). Any number of filters can then be instantiated using that +set of coefficients with \ref iir_filter_new(), or the coefficients can be +chained on to the end of an existing filter instance with +\ref iir_filter_chain(). See \ref common_filters for functions to generate +coefficients. + +\section operation Filter operation + +The function \ref iir_filter() will actually process an input sample through the +coefficient chain and produce the output sample. Effectively it produces +y(t) given x(t). + +A filter may be copied, possibly including its state (for initial conditions), +using the function \ref iir_filter_copy(). + +\section tools Tools + +In the tests directory are some simple tools for examining and +experimenting with filters. run_filter takes a stream of input +samples x(t) and produces the filtered output samples +y(t). + +Perhaps more interesting is plot_filter (requires GNUplot to be +installed) which will generate a Bode plot for a given filter chain. Note the +phase response can be a little rough due to the simplistic time-domain analysis +of the output signal's phase. + +*/ + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=doxygen +*/ diff --git a/src/docs/build.default b/src/docs/build.default new file mode 100644 index 0000000..ca22639 --- /dev/null +++ b/src/docs/build.default @@ -0,0 +1 @@ +source src/docs/build.docs diff --git a/src/docs/build.docs b/src/docs/build.docs new file mode 100644 index 0000000..98d0570 --- /dev/null +++ b/src/docs/build.docs @@ -0,0 +1,43 @@ +# These are external variables, and shouldn't clash with anything else +# docs_BUILT +# + +MONOLITHIC_DOC="${MONOLITHIC_DOC} $(echo src/docs/*.dox)" +build_target monolithic + +if [ -z ${docs_BUILT} ] +then + echo "Building documentation with Doxygen..." + + DOXYFILE=obj/Doxyfile.docs + + if [ ! -e ${DOXYFILE} ] + then + do_cmd cp src/docs/Doxyfile.in ${DOXYFILE} || return 1 + echo "INPUT = ${MONOLITHIC_DOC}" >> ${DOXYFILE} + echo "PROJECT_NUMBER = ${VERSION}" >> ${DOXYFILE} + fi + + MODIFIED=0 + for file in ${MONOLITHIC_DOC} + do + if [ ${file} -nt html/index.html ] + then + MODIFIED=1 + break + fi + done + + if [ ${MODIFIED} -ne 0 ] + then + do_cmd doxygen ${DOXYFILE} || return 1 + print_success "Documentation built" + else + print_success "Documentation is up to date" + fi + + docs_BUILT=1 +fi + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/docs/build.install b/src/docs/build.install new file mode 100644 index 0000000..016c75c --- /dev/null +++ b/src/docs/build.install @@ -0,0 +1 @@ +source src/docs/build.install-docs diff --git a/src/docs/build.install-docs b/src/docs/build.install-docs new file mode 100644 index 0000000..28f5f18 --- /dev/null +++ b/src/docs/build.install-docs @@ -0,0 +1,21 @@ +build_target docs + +# create documentation directories +echo "Installing documentation into ${DOCSDIR}" +build_dir_tree "${DOCSDIR}/html" || return 1 + +# copy across the Doxygen-generated documentation +for file in html/* +do + install_file ${file} ${DOCSDIR}/html 0644 || return 1 +done + +# copy across the generic files +for file in COPYING README +do + install_file ${file} ${DOCSDIR} 0644 || return 1 +done + +print_success "Documentation installed" +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/docs/iir_structure.dox b/src/docs/iir_structure.dox new file mode 100644 index 0000000..08af02e --- /dev/null +++ b/src/docs/iir_structure.dox @@ -0,0 +1,29 @@ +/* libiir/src/docs/iir_structure.dox + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +/*! \page iir_structure Structure of IIR filter + +For the purposes of this library, the following notation is used: + +\li x(t): value of input function at time \a t (\a t = 0, 1, 2, …) +\li y(t): value of output at time \a t +\li c[n]: array of \c x(t) coefficients +\li d[n]: array of \c y(t) coefficients + +This leads to a general IIR filter equation: + +y(t) = x(t).c[0] + x(t-1).c[1] + … + x(t-N).c[N] - y(t-1).d[0] - y(t-2).d[1] - … - y(t-1-M).d[M] + +For initial conditions, the library sets y(t) for t < 0 to 0, +and x(t) for t < 0 to x(0). + +*/ + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=doxygen +*/ diff --git a/src/docs/string_desc.dox b/src/docs/string_desc.dox new file mode 100644 index 0000000..3161afb --- /dev/null +++ b/src/docs/string_desc.dox @@ -0,0 +1,59 @@ +/* libiir/src/docs/string_desc.dox + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +/*! \page string_desc Describing IIR filters as strings + +This library allows the user to describe an IIR filter chain as a string, which +is useful to allow configurable filtering using e.g. a configuration file. This +page describes the format of such strings. + +The string is first split into individual IIR filters. Each filter is written as +\c type(params) and separated by whitespace. The string must contain at least +one filter but may contain an arbitrary number. + + + +\section string_desc_types Description of filter types + + + +\subsection string_desc_coeff Raw coefficients + +An IIR filter may be specified as raw coefficients, in which case the \c type +is \c raw and the \c params consists of a string: + +c[0],c[1],…,c[n]/d[0],d[1]…d[n] + +The coefficients c[0]…c[i] and d[0]…d[i] are written +in standard C floating-point notation. They are separated by commas, except the +transition between \c c and \c d coefficients, which is separated by a slash. + + + +\subsection string_desc_bwlp Butterworth filters + +For a low-pass filter, type is \c butterworth_lowpass. For a high-pass filter, +type is \c butterworth_highpass. Parameters as per +\ref iir_butterworth_lowpass(), i.e.: + +order,gain,corner + +For band-pass filters, type is \c butterworth_bandpass. For band-stop filters, +type is \c butterworth_bandstop. Parameters as per +\ref iir_butterworth_bandpass(), i.e.: + +order,gain,low_corner,high_corner + +Anything greater than 4th order will be split into multiple 4th-order (or less) +segments. Note however this will lead to the corner frequencies being off. + +*/ + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=doxygen +*/ diff --git a/src/libiir/.params b/src/libiir/.params new file mode 100644 index 0000000..8b7ab75 --- /dev/null +++ b/src/libiir/.params @@ -0,0 +1 @@ +lib c libiir iir.h diff --git a/src/libiir/000_TopHeader.h b/src/libiir/000_TopHeader.h new file mode 100644 index 0000000..b5a678e --- /dev/null +++ b/src/libiir/000_TopHeader.h @@ -0,0 +1,16 @@ +/* libiir/src/libiir/000_TopHeader.h + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#ifndef HEADER_libiir +#define HEADER_libiir + +/* standard includes, or includes needed for type declarations */ + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/000_TopSource.c b/src/libiir/000_TopSource.c new file mode 100644 index 0000000..ce5ca2d --- /dev/null +++ b/src/libiir/000_TopSource.c @@ -0,0 +1,20 @@ +/* libiir/src/libiir/000_TopSource.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#include "iir.h" + +/* Below are all the includes used throughout the library. */ +#include +#include +#include +#include +#include + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/src/libiir/200_iir.c b/src/libiir/200_iir.c new file mode 100644 index 0000000..91db516 --- /dev/null +++ b/src/libiir/200_iir.c @@ -0,0 +1,248 @@ +/* libiir/src/libiir/200_iir.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/* struct iir_coeff_t + * Holds a general IIR filter (i.e. the set of coefficients that define it). + * nc >= 1 and nd >= 1. + */ +struct iir_coeff_t { + int nc, nd; + double* c, * d; +}; + + + +/* iir_coeff_new() + * Allocates a new set of coefficient objects. + */ +struct iir_coeff_t* +iir_coeff_new(int nc, double* c, int nd, double* d) +{ + struct iir_coeff_t* coeff; + + if(nc < 1 || nd < 1) { + errno = EINVAL; + return 0; + } + + coeff = malloc(sizeof(struct iir_coeff_t)); + coeff->nc = nc; + coeff->nd = nd; + coeff->c = malloc(sizeof(double) * nc); + coeff->d = malloc(sizeof(double) * nd); + memcpy(coeff->c, c, sizeof(double) * nc); + memcpy(coeff->d, d, sizeof(double) * nd); + + return coeff; +} + + + +/* iir_coeff_free() + * Frees memory associated with ‘coeff’. + */ +void +iir_coeff_free(struct iir_coeff_t* coeff) +{ + if(!coeff) return; + free(coeff->c); + free(coeff->d); + free(coeff); +} + + + +/* struct iir_filter_t + * An instantiated IIR filter. This is actually a linked list node, so that we + * can create chains of filters. It also has a copy of the coefficients so that + * the library user doesn't need to keep the struct iir_coeff_t instances + * around. + */ +struct iir_filter_t { + /* pointer to next stage */ + struct iir_filter_t* next; + + /* coefficients for this stage */ + int nc, nd; + double* c, * d; + + /* state for this stage */ + int ready; /* if clear, first sample is used to set initial conditions */ + double* x, * y; + int xpos, ypos; +}; + + + +/* iir_filter_new() + * Allocates a new IIR filter instance object, copying the coefficients out of + * ‘coeff’. + */ +struct iir_filter_t* +iir_filter_new(const struct iir_coeff_t* coeff) +{ + struct iir_filter_t* fi; + + fi = malloc(sizeof(struct iir_filter_t)); + fi->next = 0; + fi->ready = fi->xpos = fi->ypos = 0; + + /* copy in the coefficients */ + fi->nc = coeff->nc; + fi->nd = coeff->nd; + fi->c = malloc(sizeof(double) * fi->nc); + fi->d = malloc(sizeof(double) * fi->nd); + memcpy(fi->c, coeff->c, sizeof(double) * fi->nc); + memcpy(fi->d, coeff->d, sizeof(double) * fi->nd); + + /* allocate space for state */ + fi->x = malloc(sizeof(double) * fi->nc); + fi->y = malloc(sizeof(double) * fi->nd); + memset(fi->y, 0, sizeof(double) * fi->nd); + + return fi; +} + + + +/* iir_filter_free() + * Frees a filter chain. + */ +void +iir_filter_free(struct iir_filter_t* fi) +{ + struct iir_filter_t* next; + + while(fi) { + next = fi->next; + free(fi->c); + free(fi->d); + free(fi->x); + free(fi->y); + free(fi); + fi = next; + } +} + + + +/* iir_filter_chain() + * Extends an IIR filter instance with another filter. + */ +void +iir_filter_chain(struct iir_filter_t* fi, const struct iir_coeff_t* coeff) +{ + /* go to end of linked list */ + while(fi->next) fi = fi->next; + + /* add to end of chain */ + fi->next = iir_filter_new(coeff); +} + + + +/* iir_filter_copy() + * Performs a deep copy of a filter instance chain. + */ +struct iir_filter_t* iir_filter_copy(const struct iir_filter_t* fi, int state) +{ + struct iir_filter_t* head = 0, * tail = 0, * copy; + + while(fi) { + copy = malloc(sizeof(struct iir_filter_t)); + copy->next = 0; + copy->nc = fi->nc; + copy->nd = fi->nd; + copy->c = malloc(sizeof(double) * fi->nc); + copy->x = malloc(sizeof(double) * fi->nc); + copy->d = malloc(sizeof(double) * fi->nd); + copy->y = malloc(sizeof(double) * fi->nd); + memcpy(copy->c, fi->c, sizeof(double) * fi->nc); + memcpy(copy->d, fi->d, sizeof(double) * fi->nd); + + if(state) { + copy->ready = 1; + memcpy(copy->x, fi->x, sizeof(double) * fi->nc); + memcpy(copy->y, fi->y, sizeof(double) * fi->nd); + copy->xpos = fi->xpos; + copy->ypos = fi->ypos; + } else { + memset(copy->y, 0, sizeof(double) * fi->nd); + copy->ready = copy->xpos = copy->ypos = 0; + } + + if(!head) { + head = tail = copy; + } else { + tail->next = copy; + tail = copy; + } + + fi = fi->next; + } + + return head; +} + + + +/* iir_filter() + * Processes a sample, possibly dispatching it down the chain. + */ +static double +iir_get_xy(const double* xy, int pos, int max, int step) +{ + pos -= step + 1; + if(pos < 0) pos += max; + return xy[pos]; +} + +double +iir_filter(struct iir_filter_t* fi, double samp) +{ + int i; + + while(fi) { + if(!fi->ready) { + /* initial conditions */ + for(i = 0; i < fi->nc; ++i) fi->x[i] = samp; + fi->ready = 1; + } + + /* update input array with sample x(t) */ + fi->x[fi->xpos] = samp; + if(++fi->xpos == fi->nc) fi->xpos = 0; + samp = 0; + + /* sum of c[i].x(t-i) */ + for(i = 0; i < fi->nc; ++i) { + samp += fi->c[i] * iir_get_xy(fi->x, fi->xpos, fi->nc, i); + } + + /* sum of d[i].y(t-i-1) */ + for(i = 0; i < fi->nd; ++i) { + samp -= fi->d[i] * iir_get_xy(fi->y, fi->ypos, fi->nd, i); + } + + /* update output array with new result y(t) */ + fi->y[fi->ypos] = samp; + if(++fi->ypos == fi->nd) fi->ypos = 0; + + fi = fi->next; + } + + return samp; +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/src/libiir/200_iir.h b/src/libiir/200_iir.h new file mode 100644 index 0000000..53e2629 --- /dev/null +++ b/src/libiir/200_iir.h @@ -0,0 +1,169 @@ +/* libiir/src/libiir/200_iir.h + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/*! \defgroup iir Basic IIR filtering + +The functions in this module present a basic interface for representing IIR +filters, creating instances of (possibly chained) IIR filters, and filtering an +input sample. + +A general IIR filter consists of a set of coefficients, and may be created +through \ref iir_coeff_new(). The filter object (the opaque struct +iir_coeff_t) is then used to instantiate specific filters (the opaque +struct iir_filter_t) through \ref iir_filter_new(). Each filter +instance may have an arbitrary further number of IIR filters chained on to it +through \ref iir_filter_chain(). The filter processes one sample at a time +through \ref iir_filter(). + +*/ +/*!@{*/ + + + +/* opaque structure */ +struct iir_coeff_t; + + + +/*! \brief Create general IIR filter + +\param nc Number of \a c coefficients. +\param c Array of \a c coefficients. +\param nd Number of \a d coefficients. +\param d Array of \a d coefficients. +\returns Pointer to new general IIR filter object. + +This function creates a new general IIR filter object which may be used to +create filter instances through \ref iir_filter_new() or chained on to existing +instances through \ref iir_filter(). + +See \ref iir_structure for a full explanation of the parameters. + +*/ +struct iir_coeff_t* iir_coeff_new(int nc, double* c, int nd, double* d) +#ifndef DOXYGEN + __attribute__((malloc,nonnull)) +#endif +; + + + +/*! \brief Free general IIR filter + +\param coeff Pointer to IIR filter object. May be 0. + +Frees a set of IIR filter coefficients previously allocated through +\ref iir_coeff_new(). Can be called on a null pointer without consequences. +Note that \ref iir_filter_new() and \ref iir_filter_chain() actually store a +copy of the coefficients, so it is possible to free \a coeff even if existing +filters are still using its coefficient values. + +*/ +void iir_coeff_free(struct iir_coeff_t* coeff); + + + +/* opaque structure */ +struct iir_filter_t; + + + +/*! \brief Create IIR filter instance + +\param coeff Filter coefficients to use. +\returns Pointer to new instance of IIR filter. + +Creates a new instance of a general IIR filter. The set of coefficients \a coeff +is copied into the returned structure, meaning the coefficients can be freed +after this function returns if they will not be needed again. + +The first sample passed through \ref iir_filter() will be used to set initial +conditions. + +An arbitrary number of further filters may be chained on to the end of this +instance through \ref iir_filter_chain(). + +*/ +struct iir_filter_t* iir_filter_new(const struct iir_coeff_t* coeff) +#ifndef DOXYGEN + __attribute__((malloc,nonnull)) +#endif +; + + + +/*! \brief Free IIR filter instance + +\param fi Filter object to free. May be 0. + +Frees a previously-allocated IIR filter instance. Can be called on a null +pointer without consequences. + +*/ +void iir_filter_free(struct iir_filter_t* fi); + + + +/*! \brief Add a further IIR filter to a filter instance + +\param fi Filter instance to chain onto. +\param coeff New IIR filter coefficients to add to chain. + +Extends an existing IIR filter by chaining a new set of coefficients onto the +end. This can be used for >4th order Butterworth filters, for example. This +copies the set of coefficients from \a coeff so the coefficients can be freed +after this function returns if they are no longer required. + +*/ +void iir_filter_chain(struct iir_filter_t* fi, const struct iir_coeff_t* coeff) +#ifndef DOXYGEN + __attribute__((nonnull)) +#endif +; + + + +/*! \brief Create a deep copy of an IIR filter instance + +\param fi Filter instance to copy. +\param state Non-zero to copy state as well. +\returns Pointer to newly-allocated filter instance. + +Performs a deep copy of the filter instance \a fi. If \a state is non-zero, +then the internal state of \a fi is copied as well (otherwise it is as treated +as a brand new instance). + +*/ +struct iir_filter_t* iir_filter_copy(const struct iir_filter_t* fi, int state) +#ifndef DOXYGEN + __attribute__((malloc,nonnull)) +#endif +; + + + +/*! \brief Process a sample + +\param fi Filter object to run. +\param samp Input sample \c x(t). +\returns Filtered output sample \c y(t). + +Given the input sample \c x(t) (the parameter \a samp), runs the filter chain in +\a fi and produces the output sample \c y(t), which it returns. + +*/ +double iir_filter(struct iir_filter_t* fi, double samp); + + + +/*!@}*/ +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/300_common_filters.h b/src/libiir/300_common_filters.h new file mode 100644 index 0000000..897827b --- /dev/null +++ b/src/libiir/300_common_filters.h @@ -0,0 +1,161 @@ +/* libiir/src/libiir/300_common_filters.h + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/*! \defgroup common_filters Common types of IIR filter + +Functions to create coefficients for various common types of IIR filter. The +coefficient structures which are returned may be used to instantiate IIR +filters using \ref iir_filter_new(). + +The Butterworth filter code comes from the Exstrom Labs LLC code available under +GPLv2 or later and published at http://www.exstrom.com/journal/sigproc/ . There +is a copy of the original code available in the top level of this project. + +*/ +/*!@{*/ + + + +/*! \brief nth-order Butterworth low-pass + +\param order Order of filter (≥1). +\param gain Linear gain of filter. +\param corner Corner frequency expressed as a fraction of Nyquist + (0 ≤ \a corner ≤ 1) +\returns Newly-allocated IIR filter coefficients. + +Uses the Exstrom labs code to compute the coefficients of an nth-order (param +\a order) Butterworth-type low pass filter with gain \a gain and corner +frequency \a corner. + +Note it is recommended to chain multiple filters together to build anything +greater than a 4th-order filter. This function won't do that directly for you. +\a gain will usually be set to be 1.0. + +The corner frequency \a corner is expressed as a fraction of the sampling +frequency (which is of course not known by the IIR code). It should lie between +0 (0Hz) and 1 (the Nyquist frequency, or ½ the sampling frequency). + +*/ +struct iir_coeff_t* iir_butterworth_lowpass(int order, + double gain, + double corner) +#ifndef DOXYGEN + __attribute__((nonnull)) +#endif +; + + + +/*! \brief nth-order Butterworth high-pass + +\param order Order of filter (≥1). +\param gain Linear gain of filter. +\param corner Corner frequency expressed as a fraction of Nyquist + (0 ≤ \a corner ≤ 1) +\returns Newly-allocated IIR filter coefficients. + +Uses the Exstrom labs code to compute the coefficients of an nth-order (param +\a order) Butterworth-type high pass filter with gain \a gain and corner +frequency \a corner. + +Note it is recommended to chain multiple filters together to build anything +greater than a 4th-order filter. This function won't do that directly for you. +\a gain will usually be set to be 1.0. + +The corner frequency \a corner is expressed as a fraction of the sampling +frequency (which is of course not known by the IIR code). It should lie between +0 (0Hz) and 1 (the Nyquist frequency, or ½ the sampling frequency). + +*/ +struct iir_coeff_t* iir_butterworth_highpass(int order, + double gain, + double corner) +#ifndef DOXYGEN + __attribute__((nonnull)) +#endif +; + + + +/*! \brief nth-order Butterworth band-pass + +\param order Order of filter (≥1). +\param gain Linear gain of filter. +\param c1 Low corner frequency expressed as a fraction of Nyquist + (0 ≤ \a c1 ≤ 1) +\param c2 High corner frequency expressed as a fraction of Nyquist + (0 ≤ \a c2 ≤ 1, and \a c1 < \a c2) +\returns Newly-allocated IIR filter coefficients. + +Uses the Exstrom labs code to compute the coefficients of an nth-order (param +\a order) Butterworth-type band pass filter with gain \a gain and corner +frequencies \a c1 and \a c2. + +Note it is recommended to chain multiple filters together to build anything +greater than a 4th-order filter. This function won't do that directly for you. +\a gain will usually be set to be 1.0. + +The corner frequencies \a c1 and \a c2 are expressed as a fraction of the +sampling frequency (which is of course not known by the IIR code). They should +lie between 0 (0Hz) and 1 (the Nyquist frequency, or ½ the sampling frequency), +and \a c2 should be greater than \a c1. + +*/ +struct iir_coeff_t* iir_butterworth_bandpass(int order, + double gain, + double c1, + double c2) +#ifndef DOXYGEN + __attribute__((nonnull)) +#endif +; + + + +/*! \brief nth-order Butterworth band-stop + +\param order Order of filter (≥1). +\param gain Linear gain of filter. +\param c1 Low corner frequency expressed as a fraction of Nyquist + (0 ≤ \a c1 ≤ 1) +\param c2 High corner frequency expressed as a fraction of Nyquist + (0 ≤ \a c2 ≤ 1, and \a c1 < \a c2) +\returns Newly-allocated IIR filter coefficients. + +Uses the Exstrom labs code to compute the coefficients of an nth-order (param +\a order) Butterworth-type band stop filter with gain \a gain and corner +frequencies \a c1 and \a c2. + +Note it is recommended to chain multiple filters together to build anything +greater than a 4th-order filter. This function won't do that directly for you. +\a gain will usually be set to be 1.0. + +The corner frequencies \a c1 and \a c2 are expressed as a fraction of the +sampling frequency (which is of course not known by the IIR code). They should +lie between 0 (0Hz) and 1 (the Nyquist frequency, or ½ the sampling frequency), +and \a c2 should be greater than \a c1. + +*/ +struct iir_coeff_t* iir_butterworth_bandstop(int order, + double gain, + double c1, + double c2) +#ifndef DOXYGEN + __attribute__((nonnull)) +#endif +; + + + +/*!@}*/ +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/300_common_filters/000_exstrom_butterworth.c b/src/libiir/300_common_filters/000_exstrom_butterworth.c new file mode 100644 index 0000000..134ca8b --- /dev/null +++ b/src/libiir/300_common_filters/000_exstrom_butterworth.c @@ -0,0 +1,600 @@ +/* Modifications for libiir: + * · added ‘static’ qualifiers to all functions + * · removed #include lines, they are covered by 000_TopSource.c + * + * These changes are: + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 + */ + + +/* + * COPYRIGHT + * + * liir - Recursive digital filter functions + * Copyright (C) 2007 Exstrom Laboratories LLC + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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. + * + * A copy of the GNU General Public License is available on the internet at: + * + * http://www.gnu.org/copyleft/gpl.html + * + * or you can write to: + * + * The Free Software Foundation, Inc. + * 675 Mass Ave + * Cambridge, MA 02139, USA + * + * You can contact Exstrom Laboratories LLC via Email at: + * + * stefan(AT)exstrom.com + * + * or you can write to: + * + * Exstrom Laboratories LLC + * P.O. Box 7651 + * Longmont, CO 80501, USA + * + */ + + +/********************************************************************** + binomial_mult - multiplies a series of binomials together and returns + the coefficients of the resulting polynomial. + + The multiplication has the following form: + + (x+p[0])*(x+p[1])*...*(x+p[n-1]) + + The p[i] coefficients are assumed to be complex and are passed to the + function as a pointer to an array of doubles of length 2n. + + The resulting polynomial has the following form: + + x^n + a[0]*x^n-1 + a[1]*x^n-2 + ... +a[n-2]*x + a[n-1] + + The a[i] coefficients can in general be complex but should in most + cases turn out to be real. The a[i] coefficients are returned by the + function as a pointer to an array of doubles of length 2n. Storage + for the array is allocated by the function and should be freed by the + calling program when no longer needed. + + Function arguments: + + n - The number of binomials to multiply + p - Pointer to an array of doubles where p[2i] (i=0...n-1) is + assumed to be the real part of the coefficient of the ith binomial + and p[2i+1] is assumed to be the imaginary part. The overall size + of the array is then 2n. +*/ + +static double * +binomial_mult( int n, double *p ) +{ + int i, j; + double *a; + + a = (double *)calloc( 2 * n, sizeof(double) ); + if( a == NULL ) return( NULL ); + + for( i = 0; i < n; ++i ) + { + for( j = i; j > 0; --j ) + { + a[2*j] += p[2*i] * a[2*(j-1)] - p[2*i+1] * a[2*(j-1)+1]; + a[2*j+1] += p[2*i] * a[2*(j-1)+1] + p[2*i+1] * a[2*(j-1)]; + } + a[0] += p[2*i]; + a[1] += p[2*i+1]; + } + return( a ); +} + + +/********************************************************************** + trinomial_mult - multiplies a series of trinomials together and returns + the coefficients of the resulting polynomial. + + The multiplication has the following form: + + (x^2 + b[0]x + c[0])*(x^2 + b[1]x + c[1])*...*(x^2 + b[n-1]x + c[n-1]) + + The b[i] and c[i] coefficients are assumed to be complex and are passed + to the function as a pointers to arrays of doubles of length 2n. The real + part of the coefficients are stored in the even numbered elements of the + array and the imaginary parts are stored in the odd numbered elements. + + The resulting polynomial has the following form: + + x^2n + a[0]*x^2n-1 + a[1]*x^2n-2 + ... +a[2n-2]*x + a[2n-1] + + The a[i] coefficients can in general be complex but should in most cases + turn out to be real. The a[i] coefficients are returned by the function as + a pointer to an array of doubles of length 4n. The real and imaginary + parts are stored, respectively, in the even and odd elements of the array. + Storage for the array is allocated by the function and should be freed by + the calling program when no longer needed. + + Function arguments: + + n - The number of trinomials to multiply + b - Pointer to an array of doubles of length 2n. + c - Pointer to an array of doubles of length 2n. +*/ + +static double * +trinomial_mult( int n, double *b, double *c ) +{ + int i, j; + double *a; + + a = (double *)calloc( 4 * n, sizeof(double) ); + if( a == NULL ) return( NULL ); + + a[2] = c[0]; + a[3] = c[1]; + a[0] = b[0]; + a[1] = b[1]; + + for( i = 1; i < n; ++i ) + { + a[2*(2*i+1)] += c[2*i]*a[2*(2*i-1)] - c[2*i+1]*a[2*(2*i-1)+1]; + a[2*(2*i+1)+1] += c[2*i]*a[2*(2*i-1)+1] + c[2*i+1]*a[2*(2*i-1)]; + + for( j = 2*i; j > 1; --j ) + { + a[2*j] += b[2*i] * a[2*(j-1)] - b[2*i+1] * a[2*(j-1)+1] + + c[2*i] * a[2*(j-2)] - c[2*i+1] * a[2*(j-2)+1]; + a[2*j+1] += b[2*i] * a[2*(j-1)+1] + b[2*i+1] * a[2*(j-1)] + + c[2*i] * a[2*(j-2)+1] + c[2*i+1] * a[2*(j-2)]; + } + + a[2] += b[2*i] * a[0] - b[2*i+1] * a[1] + c[2*i]; + a[3] += b[2*i] * a[1] + b[2*i+1] * a[0] + c[2*i+1]; + a[0] += b[2*i]; + a[1] += b[2*i+1]; + } + + return( a ); +} + + +/********************************************************************** + dcof_bwlp - calculates the d coefficients for a butterworth lowpass + filter. The coefficients are returned as an array of doubles. + +*/ + +static double * +dcof_bwlp( int n, double fcf ) +{ + int k; // loop variables + double theta; // M_PI * fcf / 2.0 + double st; // sine of theta + double ct; // cosine of theta + double parg; // pole angle + double sparg; // sine of the pole angle + double cparg; // cosine of the pole angle + double a; // workspace variable + double *rcof; // binomial coefficients + double *dcof; // dk coefficients + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + if( rcof == NULL ) return( NULL ); + + theta = M_PI * fcf; + st = sin(theta); + ct = cos(theta); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + st*sparg; + rcof[2*k] = -ct/a; + rcof[2*k+1] = -st*cparg/a; + } + + dcof = binomial_mult( n, rcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + dcof_bwhp - calculates the d coefficients for a butterworth highpass + filter. The coefficients are returned as an array of doubles. + +*/ + +static double * +dcof_bwhp( int n, double fcf ) +{ + return( dcof_bwlp( n, fcf ) ); +} + + +/********************************************************************** + dcof_bwbp - calculates the d coefficients for a butterworth bandpass + filter. The coefficients are returned as an array of doubles. + +*/ + +static double * +dcof_bwbp( int n, double f1f, double f2f ) +{ + int k; // loop variables + double theta; // M_PI * (f2f - f1f) / 2.0 + double cp; // cosine of phi + double st; // sine of theta + double ct; // cosine of theta + double s2t; // sine of 2*theta + double c2t; // cosine 0f 2*theta + double *rcof; // z^-2 coefficients + double *tcof; // z^-1 coefficients + double *dcof; // dk coefficients + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a; // workspace variables + + cp = cos(M_PI * (f2f + f1f) / 2.0); + theta = M_PI * (f2f - f1f) / 2.0; + st = sin(theta); + ct = cos(theta); + s2t = 2.0*st*ct; // sine of 2*theta + c2t = 2.0*ct*ct - 1.0; // cosine of 2*theta + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + tcof = (double *)calloc( 2 * n, sizeof(double) ); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + s2t*sparg; + rcof[2*k] = c2t/a; + rcof[2*k+1] = s2t*cparg/a; + tcof[2*k] = -2.0*cp*(ct+st*sparg)/a; + tcof[2*k+1] = -2.0*cp*st*cparg/a; + } + + dcof = trinomial_mult( n, tcof, rcof ); + free( tcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= 2*n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + dcof_bwbs - calculates the d coefficients for a butterworth bandstop + filter. The coefficients are returned as an array of doubles. + +*/ + +static double * +dcof_bwbs( int n, double f1f, double f2f ) +{ + int k; // loop variables + double theta; // M_PI * (f2f - f1f) / 2.0 + double cp; // cosine of phi + double st; // sine of theta + double ct; // cosine of theta + double s2t; // sine of 2*theta + double c2t; // cosine 0f 2*theta + double *rcof; // z^-2 coefficients + double *tcof; // z^-1 coefficients + double *dcof; // dk coefficients + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a; // workspace variables + + cp = cos(M_PI * (f2f + f1f) / 2.0); + theta = M_PI * (f2f - f1f) / 2.0; + st = sin(theta); + ct = cos(theta); + s2t = 2.0*st*ct; // sine of 2*theta + c2t = 2.0*ct*ct - 1.0; // cosine 0f 2*theta + + rcof = (double *)calloc( 2 * n, sizeof(double) ); + tcof = (double *)calloc( 2 * n, sizeof(double) ); + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = sin(parg); + cparg = cos(parg); + a = 1.0 + s2t*sparg; + rcof[2*k] = c2t/a; + rcof[2*k+1] = -s2t*cparg/a; + tcof[2*k] = -2.0*cp*(ct+st*sparg)/a; + tcof[2*k+1] = 2.0*cp*st*cparg/a; + } + + dcof = trinomial_mult( n, tcof, rcof ); + free( tcof ); + free( rcof ); + + dcof[1] = dcof[0]; + dcof[0] = 1.0; + for( k = 3; k <= 2*n; ++k ) + dcof[k] = dcof[2*k-2]; + return( dcof ); +} + +/********************************************************************** + ccof_bwlp - calculates the c coefficients for a butterworth lowpass + filter. The coefficients are returned as an array of integers. + +*/ + +static int * +ccof_bwlp( int n ) +{ + int *ccof; + int m; + int i; + + ccof = (int *)calloc( n+1, sizeof(int) ); + if( ccof == NULL ) return( NULL ); + + ccof[0] = 1; + ccof[1] = n; + m = n/2; + for( i=2; i <= m; ++i) + { + ccof[i] = (n-i+1)*ccof[i-1]/i; + ccof[n-i]= ccof[i]; + } + ccof[n-1] = n; + ccof[n] = 1; + + return( ccof ); +} + +/********************************************************************** + ccof_bwhp - calculates the c coefficients for a butterworth highpass + filter. The coefficients are returned as an array of integers. + +*/ + +static int * +ccof_bwhp( int n ) +{ + int *ccof; + int i; + + ccof = ccof_bwlp( n ); + if( ccof == NULL ) return( NULL ); + + for( i = 0; i <= n; ++i) + if( i % 2 ) ccof[i] = -ccof[i]; + + return( ccof ); +} + +/********************************************************************** + ccof_bwbp - calculates the c coefficients for a butterworth bandpass + filter. The coefficients are returned as an array of integers. + +*/ + +static int * +ccof_bwbp( int n ) +{ + int *tcof; + int *ccof; + int i; + + ccof = (int *)calloc( 2*n+1, sizeof(int) ); + if( ccof == NULL ) return( NULL ); + + tcof = ccof_bwhp(n); + if( tcof == NULL ) return( NULL ); + + for( i = 0; i < n; ++i) + { + ccof[2*i] = tcof[i]; + ccof[2*i+1] = 0.0; + } + ccof[2*n] = tcof[n]; + + free( tcof ); + return( ccof ); +} + +/********************************************************************** + ccof_bwbs - calculates the c coefficients for a butterworth bandstop + filter. The coefficients are returned as an array of integers. + +*/ + +static double * +ccof_bwbs( int n, double f1f, double f2f ) +{ + double alpha; + double *ccof; + int i, j; + + alpha = -2.0 * cos(M_PI * (f2f + f1f) / 2.0) / cos(M_PI * (f2f - f1f) / 2.0); + + ccof = (double *)calloc( 2*n+1, sizeof(double) ); + + ccof[0] = 1.0; + + ccof[2] = 1.0; + ccof[1] = alpha; + + for( i = 1; i < n; ++i ) + { + ccof[2*i+2] += ccof[2*i]; + for( j = 2*i; j > 1; --j ) + ccof[j+1] += alpha * ccof[j] + ccof[j-1]; + + ccof[2] += alpha * ccof[1] + 1.0; + ccof[1] += alpha; + } + + return( ccof ); +} + +/********************************************************************** + sf_bwlp - calculates the scaling factor for a butterworth lowpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +static double +sf_bwlp( int n, double fcf ) +{ + int m, k; // loop variables + double omega; // M_PI * fcf + double fomega; // function of omega + double parg0; // zeroth pole angle + double sf; // scaling factor + + omega = M_PI * fcf; + fomega = sin(omega); + parg0 = M_PI / (double)(2*n); + + m = n / 2; + sf = 1.0; + for( k = 0; k < n/2; ++k ) + sf *= 1.0 + fomega * sin((double)(2*k+1)*parg0); + + fomega = sin(omega / 2.0); + + if( n % 2 ) sf *= fomega + cos(omega / 2.0); + sf = pow( fomega, n ) / sf; + + return(sf); +} + +/********************************************************************** + sf_bwhp - calculates the scaling factor for a butterworth highpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +static double +sf_bwhp( int n, double fcf ) +{ + int m, k; // loop variables + double omega; // M_PI * fcf + double fomega; // function of omega + double parg0; // zeroth pole angle + double sf; // scaling factor + + omega = M_PI * fcf; + fomega = sin(omega); + parg0 = M_PI / (double)(2*n); + + m = n / 2; + sf = 1.0; + for( k = 0; k < n/2; ++k ) + sf *= 1.0 + fomega * sin((double)(2*k+1)*parg0); + + fomega = cos(omega / 2.0); + + if( n % 2 ) sf *= fomega + sin(omega / 2.0); + sf = pow( fomega, n ) / sf; + + return(sf); +} + +/********************************************************************** + sf_bwbp - calculates the scaling factor for a butterworth bandpass filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +static double +sf_bwbp( int n, double f1f, double f2f ) +{ + int k; // loop variables + double ctt; // cotangent of theta + double sfr, sfi; // real and imaginary parts of the scaling factor + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a, b, c; // workspace variables + + ctt = 1.0 / tan(M_PI * (f2f - f1f) / 2.0); + sfr = 1.0; + sfi = 0.0; + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = ctt + sin(parg); + cparg = cos(parg); + a = (sfr + sfi)*(sparg - cparg); + b = sfr * sparg; + c = -sfi * cparg; + sfr = b - c; + sfi = a - b - c; + } + + return( 1.0 / sfr ); +} + +/********************************************************************** + sf_bwbs - calculates the scaling factor for a butterworth bandstop filter. + The scaling factor is what the c coefficients must be multiplied by so + that the filter response has a maximum value of 1. + +*/ + +static double +sf_bwbs( int n, double f1f, double f2f ) +{ + int k; // loop variables + double tt; // tangent of theta + double sfr, sfi; // real and imaginary parts of the scaling factor + double parg; // pole angle + double sparg; // sine of pole angle + double cparg; // cosine of pole angle + double a, b, c; // workspace variables + + tt = tan(M_PI * (f2f - f1f) / 2.0); + sfr = 1.0; + sfi = 0.0; + + for( k = 0; k < n; ++k ) + { + parg = M_PI * (double)(2*k+1)/(double)(2*n); + sparg = tt + sin(parg); + cparg = cos(parg); + a = (sfr + sfi)*(sparg - cparg); + b = sfr * sparg; + c = -sfi * cparg; + sfr = b - c; + sfi = a - b - c; + } + + return( 1.0 / sfr ); +} diff --git a/src/libiir/300_common_filters/100_butterworth.c b/src/libiir/300_common_filters/100_butterworth.c new file mode 100644 index 0000000..dcd740a --- /dev/null +++ b/src/libiir/300_common_filters/100_butterworth.c @@ -0,0 +1,178 @@ +/* libiir/src/libiir/300_common_filters/100_butterworth.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/* Each of the functions below is an impedance-matching layer between the + * Exstrom code (in 000_exstrom_butterworth.c) and libiir. Although there is a + * fair bit of code duplication, there are just enough subtle differences in the + * interface and implementation of the Exstrom code to make abstracting these + * four functions into one more effort than it is worth. + */ + + + +struct iir_coeff_t* iir_butterworth_lowpass(int order, + double gain, + double corner) +{ + int i, nc, nd, * ci; + double* d, * c; + struct iir_coeff_t* coeff; + + if(order < 1 || corner < 0 || corner > 1) { + errno = EINVAL; + return 0; + } + + /* get coefficients from Exstrom code */ + d = dcof_bwlp(order, corner); + nd = order + 1; + ci = ccof_bwlp(order); + nc = order + 1; + gain *= sf_bwlp(order, corner); + + /* compute scaled ‘c’ coefficients */ + c = malloc(sizeof(double) * nc); + for(i = 0; i < nc; ++i) c[i] = ci[i] * gain; + + /* Instantiate filter structure. Note in Exstrom code that d[0] is always + * 1.0 and not used; the Güralp code doesn't represent it, hence the shift + * by 1. */ + coeff = iir_coeff_new(nc, c, nd - 1, d + 1); + + /* clean up */ + free(ci); + free(c); + free(d); + + return coeff; +} + + + +struct iir_coeff_t* iir_butterworth_highpass(int order, + double gain, + double corner) +{ + int i, nc, nd, * ci; + double* d, * c; + struct iir_coeff_t* coeff; + + if(order < 1 || corner < 0 || corner > 1) { + errno = EINVAL; + return 0; + } + + /* get coefficients from Exstrom code */ + d = dcof_bwhp(order, corner); + nd = order + 1; + ci = ccof_bwhp(order); + nc = order + 1; + gain *= sf_bwhp(order, corner); + + /* compute scaled ‘c’ coefficients */ + c = malloc(sizeof(double) * nc); + for(i = 0; i < nc; ++i) c[i] = ci[i] * gain; + + /* Instantiate filter structure. Note in Exstrom code that d[0] is always + * 1.0 and not used; the Güralp code doesn't represent it, hence the shift + * by 1. */ + coeff = iir_coeff_new(nc, c, nd - 1, d + 1); + + /* clean up */ + free(ci); + free(c); + free(d); + + return coeff; +} + + + +struct iir_coeff_t* iir_butterworth_bandpass(int order, + double gain, + double c1, + double c2) +{ + int i, nc, nd, * ci; + double* d, * c; + struct iir_coeff_t* coeff; + + if(order < 1 || c1 < 0 || c1 > c2 || c2 > 1) { + errno = EINVAL; + return 0; + } + + /* get coefficients from Exstrom code */ + d = dcof_bwbp(order, c1, c2); + nd = 2 * order + 1; + ci = ccof_bwbp(order); + nc = 2 * order + 1; + gain *= sf_bwbp(order, c1, c2); + + /* compute scaled ‘c’ coefficients */ + c = malloc(sizeof(double) * nc); + for(i = 0; i < nc; ++i) c[i] = ci[i] * gain; + + /* Instantiate filter structure. Note in Exstrom code that d[0] is always + * 1.0 and not used; the Güralp code doesn't represent it, hence the shift + * by 1. */ + coeff = iir_coeff_new(nc, c, nd - 1, d + 1); + + /* clean up */ + free(ci); + free(c); + free(d); + + return coeff; +} + + + +struct iir_coeff_t* iir_butterworth_bandstop(int order, + double gain, + double c1, + double c2) +{ + int i, nc, nd; + double* d, * c; + struct iir_coeff_t* coeff; + + if(order < 1 || c1 < 0 || c1 > c2 || c2 > 1) { + errno = EINVAL; + return 0; + } + + /* get coefficients from Exstrom code */ + d = dcof_bwbs(order, c1, c2); + nd = 2 * order + 1; + c = ccof_bwbs(order, c1, c2); + nc = 2 * order + 1; + gain *= sf_bwbs(order, c1, c2); + + /* compute scaled ‘c’ coefficients */ + for(i = 0; i < nc; ++i) c[i] *= gain; + + /* Instantiate filter structure. Note in Exstrom code that d[0] is always + * 1.0 and not used; the Güralp code doesn't represent it, hence the shift + * by 1. */ + coeff = iir_coeff_new(nc, c, nd - 1, d + 1); + + /* clean up */ + free(c); + free(d); + + return coeff; +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/src/libiir/400_parser.c b/src/libiir/400_parser.c new file mode 100644 index 0000000..45b44da --- /dev/null +++ b/src/libiir/400_parser.c @@ -0,0 +1,395 @@ +/* libiir/src/libiir/400_parser.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/* IIR_PARSER_CHAIN() + * In the parser functions below, we are passed a pointer to the pointer to the + * IIR filter structure. The pointed-to pointer must be set if we are parsing + * the very first set of coefficients, or chained otherwise. (This structure is + * necessary as some of the parser functions result in multiple coefficient + * sets). This macro handles that. ‘_fi’ is of type ‘struct iir_filter_t**’. + */ +#define IIR_PARSER_CHAIN(_fi, _coeff) do { \ + if(*_fi) iir_filter_chain(*_fi, _coeff); \ + else *_fi = iir_filter_new(_coeff); \ +}while(0) + + + +/* iir_parser_raw() + * Parses raw coefficients and adds a filter to the chain ‘fi’. ‘desc’ should + * point at the parameter string; a '/' character splits the c and d + * coefficients, and a ')' character marks the end of the parameters. The aux + * function allocates and parses an array of doubles with each value separated + * by a ',' character and the array terminated by an arbitrary character + * ‘endc’. + */ +static double* +iir_parser_raw_aux(int* nout, const char** desc, char endc) +{ + int n = 0, sz = 16; + double* c, x; + char* endp; + + c = malloc(sizeof(double) * sz); + + while(1) { + /* parse a single coefficient, taking care with strtod(3) */ + errno = 0; + endp = 0; + x = strtod(*desc, &endp); + if(errno || !endp || endp == *desc) goto fail; + *desc = endp + 1; + + /* add to array */ + if(n == sz) { + sz <<= 1; + c = realloc(c, sizeof(double) * sz); + } + c[n++] = x; + + /* check for ',' or end-of-list char */ + if(*endp == ',') continue; + if(*endp != endc) goto fail; + break; + } + + /* done */ + *nout = n; + return c; + + fail: + free(c); + return 0; +} + +static int +iir_parser_raw(struct iir_filter_t** fi, const char* desc) +{ + int nc, nd; + double* c, * d; + struct iir_coeff_t* coeff; + + /* allocate and parse two arrays of double */ + c = iir_parser_raw_aux(&nc, &desc, '/'); + if(!c) return -1; + d = iir_parser_raw_aux(&nd, &desc, ')'); + if(!d) { + free(c); + return -1; + } + + /* HACK: rather than calling iir_coeff_new(), save time by not creating a + * redundant copy and just fill the structure directly */ + coeff = malloc(sizeof(struct iir_coeff_t)); + coeff->nc = nc; + coeff->nd = nd; + coeff->c = c; + coeff->d = d; + + IIR_PARSER_CHAIN(fi, coeff); + iir_coeff_free(coeff); + return 0; +} + + + +/* IIR_PARSER_BW_MAX_ORDER + * The maximum order in any single Butterworth-type filter. If the given order + * exceeds this, we split the resulting filter up into multiple sets of + * coefficients of this order or less. + */ +#define IIR_PARSER_BW_MAX_ORDER (4) + + + +/* iir_parser_bw_aux() + * Parses the Butterworth-type parameter string. ‘c2’ may be passed as null if + * the filter only has one corner frequency (low or high pass). + */ +static int +iir_parser_bw_aux(const char* desc, + int* order, + double* gain, + double* c1, + double* c2) +{ + char* endp; + + /* parse order,gain,c1 */ + errno = 0; + endp = 0; + *order = strtol(desc, &endp, 0); + if(errno || !endp || endp == desc || *endp != ',') return -1; + desc = endp + 1; + + endp = 0; + *gain = strtod(desc, &endp); + if(errno || !endp || endp == desc || *endp != ',') return -1; + desc = endp + 1; + + endp = 0; + *c1 = strtod(desc, &endp); + if(errno || !endp || endp == desc) return -1; + desc = endp + 1; + + /* if c2 is requested, parse that as well */ + if(c2) { + if(*endp != ',') return -1; + endp = 0; + *c2 = strtod(desc, &endp); + if(errno || !endp || endp == desc) return -1; + } + + /* check we used the entire parameter string */ + return *endp != ')'; +} + + + +/* iir_parser_bw_aux2() + * Instantiates a low/high pass type filter with a single corner frequency + * using the function ‘bw’. Splits into multiple filters if the order exceeds + * the threshold in IIR_PARSER_BW_MAX_ORDER. + */ +static int +iir_parser_bw_aux2(struct iir_filter_t** fi, + struct iir_coeff_t* (*bw)(int, double, double), + int order, + double gain, + double corner) +{ + struct iir_coeff_t* coeff; + + /* split into segments of 4th order or less */ + if(order >= IIR_PARSER_BW_MAX_ORDER) { + coeff = bw(IIR_PARSER_BW_MAX_ORDER, gain, corner); + if(!coeff) return -1; + while(order >= IIR_PARSER_BW_MAX_ORDER) { + IIR_PARSER_CHAIN(fi, coeff); + order -= IIR_PARSER_BW_MAX_ORDER; + } + iir_coeff_free(coeff); + if(!order) return 0; + /* add a <4th order segment */ + } + + coeff = bw(order, gain, corner); + if(!coeff) return -1; + IIR_PARSER_CHAIN(fi, coeff); + iir_coeff_free(coeff); + + return 0; +} + + + +/* iir_parser_bw_aux3() + * Instantiates a band pass/stop type filter with two corner frequencies + * using the function ‘bw’. Splits into multiple filters if the order exceeds + * the threshold in IIR_PARSER_BW_MAX_ORDER. + */ +static int +iir_parser_bw_aux3(struct iir_filter_t** fi, + struct iir_coeff_t* (*bw)(int, double, double, double), + int order, + double gain, + double c1, + double c2) +{ + struct iir_coeff_t* coeff; + + /* split into segments of 4th order or less */ + if(order >= IIR_PARSER_BW_MAX_ORDER) { + coeff = bw(IIR_PARSER_BW_MAX_ORDER, gain, c1, c2); + if(!coeff) return -1; + while(order >= IIR_PARSER_BW_MAX_ORDER) { + IIR_PARSER_CHAIN(fi, coeff); + order -= IIR_PARSER_BW_MAX_ORDER; + } + iir_coeff_free(coeff); + if(!order) return 0; + /* add a <4th order segment */ + } + + coeff = bw(order, gain, c1, c2); + if(!coeff) return -1; + IIR_PARSER_CHAIN(fi, coeff); + iir_coeff_free(coeff); + + return 0; +} + + + +/* iir_parser_bw*() + * Various Butterworth-type parsers, built out of the aux blocks above. + */ +static int +iir_parser_bwlp(struct iir_filter_t** fi, const char* desc) +{ + int order; + double gain, corner; + + /* parse order,gain,corner */ + if(iir_parser_bw_aux(desc, &order, &gain, &corner, 0)) return -1; + + /* instantiate and associate coefficients */ + return iir_parser_bw_aux2(fi, iir_butterworth_lowpass, order, gain, corner); +} + +static int +iir_parser_bwhp(struct iir_filter_t** fi, const char* desc) +{ + int order; + double gain, corner; + + /* parse order,gain,corner */ + if(iir_parser_bw_aux(desc, &order, &gain, &corner, 0)) return -1; + + /* instantiate and associate coefficients */ + return iir_parser_bw_aux2(fi, iir_butterworth_highpass, order, gain, corner); +} + +static int +iir_parser_bwbp(struct iir_filter_t** fi, const char* desc) +{ + int order; + double gain, c1, c2; + + /* parse order,gain,corner */ + if(iir_parser_bw_aux(desc, &order, &gain, &c1, &c2)) return -1; + + /* instantiate and associate coefficients */ + return iir_parser_bw_aux3(fi, iir_butterworth_bandpass, order, gain, c1, c2); +} + +static int +iir_parser_bwbs(struct iir_filter_t** fi, const char* desc) +{ + int order; + double gain, c1, c2; + + /* parse order,gain,corner */ + if(iir_parser_bw_aux(desc, &order, &gain, &c1, &c2)) return -1; + + /* instantiate and associate coefficients */ + return iir_parser_bw_aux3(fi, iir_butterworth_bandstop, order, gain, c1, c2); +} + + + +struct iir_parser_t { + const char* type; + int (*parse)(struct iir_filter_t** fi, const char* desc); +}; + +static struct iir_parser_t iir_parsers[] = { + { + .type = "raw", + .parse = iir_parser_raw, + }, + { + .type = "butterworth_lowpass", + .parse = iir_parser_bwlp, + }, + { + .type = "butterworth_highpass", + .parse = iir_parser_bwhp, + }, + { + .type = "butterworth_bandpass", + .parse = iir_parser_bwbp, + }, + { + .type = "butterworth_bandstop", + .parse = iir_parser_bwbs, + }, + { + .type = 0, + } +}; + + + +struct iir_filter_t* +iir_parse(const char* desc) +{ + const char* p, * q; + int i; + struct iir_filter_t* fi = 0; + + while(*desc) { + /* move to next filter in chain */ + if(isspace(*desc)) { + ++desc; + continue; + } + + /* verify type(args) layout */ + p = strchr(desc, '('); + q = strchr(desc, ')'); + if(!p || !q || q < p) goto fail; + + /* find matching parser function */ + for(i = 0; iir_parsers[i].type; ++i) { + if((long)strlen(iir_parsers[i].type) != p - desc) continue; + if(memcmp(iir_parsers[i].type, desc, p - desc)) continue; + break; + } + if(!iir_parsers[i].type) goto fail; + + /* parse description, add to chain */ + if(iir_parsers[i].parse(&fi, p + 1)) goto fail; + + /* consume this filter description from string */ + desc = q + 1; + } + + /* finish up */ + if(!fi) { + errno = EINVAL; + return 0; + } + return fi; + + fail: + iir_filter_free(fi); + errno = EINVAL; + return 0; +} + + + +struct iir_filter_t** +iir_parse_n(const char* desc, int n) +{ + struct iir_filter_t* fi, ** a; + int i; + + if(n < 1) { + errno = EINVAL; + return 0; + } + + fi = iir_parse(desc); + if(!fi) return 0; + + a = malloc(sizeof(struct iir_filter_t*) * n); + a[0] = fi; + for(i = 1; i < n; ++i) a[n] = iir_filter_copy(fi, 0); + + return a; +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/400_parser.h b/src/libiir/400_parser.h new file mode 100644 index 0000000..0c0c099 --- /dev/null +++ b/src/libiir/400_parser.h @@ -0,0 +1,71 @@ +/* libiir/src/libiir/400_parser.h + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + + + +/*! \defgroup parser Parser for user-specified IIR filters + +This is a high-level interface that can instantiate a set of IIR filters based +on a user-specified, human-readable string. The intention of this interface is +to allow IIR filters to be specified in configuration files so that they can be +easily modified by the user and easily understood/parsed by the system. + +See \ref string_desc for details on the string description format. + +*/ +/*!@{*/ + + + +/*! \brief Instantiate an IIR filter based on a string description + +\param desc IIR filter description. +\returns Pointer to newly-allocated IIR filter instance. +\retval 0 on error. + +Parses the human-readable description of an IIR filter chain in \a desc, +instantiating an IIR filter object to match. Returns the new filter. If \a desc +cannot be parsed correctly, returns 0 and sets \a errno to \c EINVAL. + +*/ +struct iir_filter_t* iir_parse(const char* desc) +#ifndef DOXYGEN + __attribute__((malloc,nonnull)) +#endif +; + + + +/*! \brief Instantiate a set of IIR filters based on a string description + +\param desc IIR filter description. +\param n Number of instances to allocate. +\returns Pointer to array of \a n newly-allocated IIR filter instances. +\retval 0 on error. + +Parses the human-readable description of an IIR filter chain in \a desc, +instantiating a set of \a n identical IIR filter objects to match. Returns a +pointer to an array of new filters. If \a desc cannot be parsed correctly, +returns 0 and sets \a errno to \c EINVAL. + +The user is responsible for freeing both the array elements (with +\ref iir_filter_free()) and the array itself (with \c free(3)). + +*/ +struct iir_filter_t** iir_parse_n(const char* desc, int n) +#ifndef DOXYGEN + __attribute__((malloc,nonnull)) +#endif +; + + + +/*!@}*/ +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/999_BottomHeader.h b/src/libiir/999_BottomHeader.h new file mode 100644 index 0000000..731ec5a --- /dev/null +++ b/src/libiir/999_BottomHeader.h @@ -0,0 +1,13 @@ +/* libiir/src/libiir/999_BottomHeader.h + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#endif + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4:syntax=c.doxygen +*/ diff --git a/src/libiir/build.default b/src/libiir/build.default new file mode 100644 index 0000000..2d07df4 --- /dev/null +++ b/src/libiir/build.default @@ -0,0 +1 @@ +source src/libiir/build.lib diff --git a/src/libiir/build.install b/src/libiir/build.install new file mode 100644 index 0000000..5c74ee3 --- /dev/null +++ b/src/libiir/build.install @@ -0,0 +1 @@ +source src/libiir/build.install-lib diff --git a/src/libiir/build.install-lib b/src/libiir/build.install-lib new file mode 100644 index 0000000..de4fa1e --- /dev/null +++ b/src/libiir/build.install-lib @@ -0,0 +1,38 @@ +build_target libiir + +# make paths (this is for Gentoo in particular) +build_dir_tree "${LIBDIR}" || return 1 +build_dir_tree "${BINDIR}" || return 1 +build_dir_tree "${INCLUDEDIR}" || return 1 + +# install library +echo "Installing libraries into '${LIBDIR}'" +source src/libiir/soversion +install_file ${libiir} ${LIBDIR} 0755 || return 1 +BASE="${libiir_BASE}.so" +MAJOR="${BASE}.${SOMAJOR}" +MICRO="${MAJOR}.${SOMICRO}" +install_symlink "${BASE}" "${MICRO}" "${LIBDIR}" + +# install header +echo "Installing header file '${libiir_HEADER}' into ${INCLUDEDIR}" +install_header ${libiir_HEADER} ${INCLUDEDIR} 0644 || return 1 + +# install config script +echo "Installing config script into ${BINDIR}" +CONFFILE="${INSTALL_PREFIX}${BINDIR}/libiir-config" + +do_cmd rm -f "${CONFFILE}" +do_cmd_redir "${CONFFILE}" sed \ + -e "s,@VERSION@,${VERSION}," \ + -e "s,@DEP_CFLAGS@,${libiir_DEP_CFLAGS}," \ + -e "s,@DEP_LIBS@,${libiir_DEP_LIBS}," \ + -e "s,@LIB_DIR@,${LIBDIR}," \ + -e "s,@INCLUDE_DIR@,${INCLUDEDIR}," \ + src/libiir/config-script + +do_cmd chmod 0755 "${CONFFILE}" +print_success "Done" + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/libiir/build.lib b/src/libiir/build.lib new file mode 100644 index 0000000..ba62338 --- /dev/null +++ b/src/libiir/build.lib @@ -0,0 +1,57 @@ +# These are external variables, and shouldn't clash with anything else +# libiir +# libiir_BUILT +# libiir_HEADER +# libiir_BASE +# libiir_DEP_CFLAGS +# libiir_DEP_LIBS + +if [ -z ${libiir_BUILT} ] +then + libiir_BASE=libiir + source src/libiir/soversion + + libiir="obj/${libiir_BASE}.so.${SOMAJOR}.${SOMICRO}" + libiir_DEP_CFLAGS="" + libiir_DEP_LIBS="-lm" + SO_EXTRA="-std=gnu99 -D_GNU_SOURCE \ + ${libiir_DEP_CFLAGS} ${libiir_DEP_LIBS} -lc" + + echo "Building library ${libiir}..." + + do_cmd source src/libiir/build.monolithic || return 1 + + MODIFIED=0 + for test in ${MONOLITHIC_TESTS} ${HDR} ${SRC} + do + if [ ${test} -nt ${libiir} ] + then + MODIFIED=1 + break + fi + done + + if [ ${MODIFIED} -ne 0 ] + then + echo " Compiling" + + SONAME="${libiir_BASE}.so.${SOMAJOR}" + do_cmd ${CC} ${CFLAGS} -Iobj -shared -fpic -o "${libiir}" \ + -Wl,-soname,${SONAME} \ + ${SRC} ${SO_EXTRA} || return 1 + + # make tests and linking work + do_cmd ln -sf "$(basename "${libiir}")" "obj/${SONAME}" || return 1 + do_cmd ln -sf "$(basename "${libiir}")" "obj/${libiir_BASE}.so" || return 1 + + print_success "Library built" + else + print_success "Library up to date" + fi + + libiir_BUILT=1 + libiir_HEADER=${HDR} + +fi +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/libiir/build.monolithic b/src/libiir/build.monolithic new file mode 100644 index 0000000..ea201b6 --- /dev/null +++ b/src/libiir/build.monolithic @@ -0,0 +1,21 @@ +# These are external variables, and shouldn't clash with anything else +# libiir_MONOLITHIC + +SRC="obj/libiir.c" +HDR="obj/iir.h" + +MONOLITHIC_TESTS="src/libiir/build.lib src/libiir/build.monolithic" + +if [ -z "${libiir_MONOLITHIC}" ] +then + MONOLITHIC_SOURCE="$(find src/libiir/ -name '*.h' | sort)" + make_monolithic ${HDR} Ch || return 1 + + MONOLITHIC_SOURCE="$(find src/libiir/ -name '*.c' | sort)" + make_monolithic ${SRC} C || return 1 + + libiir_MONOLITHIC=1 + MONOLITHIC_DOC="${MONOLITHIC_DOC} ${HDR}" +fi +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/libiir/config-script b/src/libiir/config-script new file mode 100644 index 0000000..00fa4f1 --- /dev/null +++ b/src/libiir/config-script @@ -0,0 +1,98 @@ +#!/bin/bash +# libiir/src/libiir/config-script +# +# libiir-config template. Variables are finalised at install time. +# +dep_cflags="@DEP_CFLAGS@" +dep_libs="@DEP_LIBS@" +include_dir="@INCLUDE_DIR@" +include_dir_set="no" +lib_dir="@LIB_DIR@" +lib_dir_set="no" + + + +usage() { + cat <&2 + + + +while [ $# -gt 0 ] +do + case "$1" in + -*=*) + optarg="$(echo "$1" | sed 's/[-_a-zA-Z0-9]*=//')" + ;; + + *) + optarg="" + ;; + esac + + case "$1" in + --libdir=*) + lib_dir="${optarg}" + lib_dir_set="yes" + ;; + + --libdir) + echo_lib_dir="yes" + ;; + + --includedir=*) + include_dir="${optarg}" + include_dir_set="yes" + ;; + + --includedir) + echo_include_dir="yes" + ;; + + --version) + echo "@VERSION@" + exit 0 + ;; + + --cflags) + [ "${include_dir}" != "/usr/include" ] && includes="-I${include_dir}" + echo_cflags="yes" + ;; + + --libs) + echo_libs="yes" + ;; + + *) + usage 1 1>&2 + ;; + esac + + shift +done + + + +[ "${echo_prefix}" == "yes" ] && echo "${prefix}" +[ "${echo_exec_prefix}" == "yes" ] && echo "${exec_prefix}" +[ "${echo_cflags}" == "yes" ] && echo "${dep_cflags} ${includes}" +[ "${echo_libs}" == "yes" ] && echo "${dep_libs} -L${lib_dir} -liir" +true + + + +# vim: syntax=sh:expandtab:ts=4:sw=4 +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; diff --git a/src/libiir/soversion b/src/libiir/soversion new file mode 100644 index 0000000..49d4c4d --- /dev/null +++ b/src/libiir/soversion @@ -0,0 +1,15 @@ +# libiir/src/libiir/soversion +# +# (c)2010, Laurence Withers, . +# Released under the GNU GPLv3. See file COPYING or +# http://www.gnu.org/copyleft/gpl.html for details. +# + + + +# SOMAJOR is included in the library's soname, and needs to be bumped +# after a binary-incompatible release. It is a single integer. +SOMAJOR=0 + +# SOMICRO is bumped every time there is a binary-compatible release. +SOMICRO=0 diff --git a/src/tests/.params b/src/tests/.params new file mode 100644 index 0000000..5bf14b4 --- /dev/null +++ b/src/tests/.params @@ -0,0 +1 @@ +tests c tests libiir diff --git a/src/tests/build.default b/src/tests/build.default new file mode 100644 index 0000000..1f0ae49 --- /dev/null +++ b/src/tests/build.default @@ -0,0 +1,3 @@ +source src/tests/build.tests +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/tests/build.tests b/src/tests/build.tests new file mode 100644 index 0000000..f5aa706 --- /dev/null +++ b/src/tests/build.tests @@ -0,0 +1,43 @@ +# These are external variables, and shouldn't clash with anything else +# tests_BUILT +# + +build_target libiir || return 1 + +if [ -z ${tests_BUILT} ] +then + LIBS="${libiir} ${libiir_DEP_CFLAGS} ${libiir_DEP_LIBS} " + EXTRAS="-D_GNU_SOURCE -std=gnu99" + + echo "Building test programs..." + do_cmd mkdir -p obj/tests || return 1 + + for SRC in src/tests/*.c + do + TEST="obj/tests/$(basename "${SRC}" ".c")" + MODIFIED=0 + for file in ${LIBS} ${SRC} src/tests/build.tests + do + if [ ${file} -nt ${TEST} ] + then + MODIFIED=1 + break + fi + done + + if [ ${MODIFIED} -ne 0 ] + then + do_cmd ${CC} -Iobj ${CFLAGS} -o ${TEST} ${SRC} ${LIBS} ${EXTRAS} || return 1 + print_success "Built ${TEST}" + else + print_success "${TEST} is up to date" + fi + done + + print_success "All tests built" + + tests_BUILT=1 +fi + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: syntax=sh:expandtab:ts=4:sw=4 diff --git a/src/tests/plot_filter.c b/src/tests/plot_filter.c new file mode 100644 index 0000000..fdba6a3 --- /dev/null +++ b/src/tests/plot_filter.c @@ -0,0 +1,271 @@ +/* libiir/src/tests/plot_filter.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#include "iir.h" + +#include +#include +#include +#include +#include +#include +#include + + + +#define NPOINTS (1000) +#define STEADY_STATE_CYCLES (20) + + + +char* tmp_fname; +void +unlink_tmpfile(void) +{ + unlink(tmp_fname); +} + + + +int +do_plot(const char* filter_desc, double samp_rat, const char* png_filename) +{ + int fd, ret; + FILE* fp; + char cmd_file[] = "/tmp/libiir-plot_filter.cmd.XXXXXX", + cmd[200]; + + fd = mkstemp(cmd_file); + if(fd == -1) { + perror("mkstemp"); + return -1; + } + + fp = fdopen(fd, "w"); + fprintf(fp, "set terminal png size 1000,1000\n" + "set output '%s'\n" + "set multiplot layout 2,1 title \"Bode plot for filter '", + png_filename); + ret = 0; + while(*filter_desc) { + if(isspace(*filter_desc)) { + if(!ret) { + ret = 1; + putc('\n', fp); + } + } else { + putc(*filter_desc, fp); + } + ++filter_desc; + } + fprintf(fp, "' at %fHz\"\n" + "set grid\n" + "set logscale\n" + "set ytics add ('-3dB' %f)\n" + "set xlabel 'Frequency (Hz)'\n" + "set ylabel 'Gain'\n" + "plot '%s' using 1:2 notitle\n" + "unset logscale y\n" + "set yrange [-180:180]\n" + "set ytics -180,45,180\n" + "set ylabel 'Phase (degrees)'\n" + "plot '%s' using 1:3 notitle\n", + samp_rat, + pow(10, -3.0/20), + tmp_fname, + tmp_fname); + fclose(fp); + + snprintf(cmd, sizeof(cmd), "gnuplot %s", cmd_file); + ret = system(cmd); + unlink(cmd_file); + + return ret; +} + + + +double +compute_magnitude(double* y, int nsamp) +{ + int samp; + double max, min; + + max = min = y[0]; + + for(samp = 1; samp < nsamp; ++samp) { + if(y[samp] > max) max = y[samp]; + if(y[samp] < min) min = y[samp]; + } + return (max - min) / 2; +} + + + +double +compute_phase_deg(double* x, double* y, int nsamp) +{ + int samp, xphase = 0, yphase = 0; + double xmax, ymax, phase; + + xmax = x[0]; + ymax = y[0]; + + for(samp = 1; samp < nsamp; ++samp) { + if(x[samp] > xmax) { + xmax = x[samp]; + xphase = samp; + } + + if(y[samp] > ymax) { + ymax = y[samp]; + yphase = samp; + } + } + + phase = (xphase - yphase) * 360.0 / nsamp; + if(phase > 180) phase -= 360; + if(phase <= -180) phase += 360; + + return phase; +} + + + +double +interp(int step, int max, double start, double end) +{ + return start + step * ((end - start) / (max - 1)); +} + +void +calc_response(FILE* fp, + struct iir_filter_t* orig_fi, + double samp_rat, + double start_freq, + double end_freq) +{ + int step, samp, cycle_len; + double freq; + struct iir_filter_t* fi; + static double* x = 0, * y = 0; + + for(step = 0; step < NPOINTS; ++step) { + freq = exp(interp(step, NPOINTS, log(start_freq), log(end_freq))); + cycle_len = samp_rat / freq + 1; + + /* HACK: allocate persistent buffer; first call must have lowest freq */ + if(!x) { + x = malloc(sizeof(double) * cycle_len); + y = malloc(sizeof(double) * cycle_len); + } + + /* HACK: build steady-state filter response */ + fi = iir_filter_copy(orig_fi, 0); + for(samp = 0; samp < cycle_len * STEADY_STATE_CYCLES; ++samp) { + iir_filter(fi, sin(2 * M_PI * freq / samp_rat * samp)); + } + + /* run and record one complete cycle */ + for(samp = 0; samp < cycle_len; ++samp) { + x[samp] = sin(2 * M_PI * freq / samp_rat * + (samp + cycle_len * STEADY_STATE_CYCLES)); + y[samp] = iir_filter(fi, x[samp]); + } + + iir_filter_free(fi); + fprintf(fp, "%e\t%e\t% 6.2f\n", + freq, + compute_magnitude(y, cycle_len), + compute_phase_deg(x, y, cycle_len)); + } +} + + + +int +safe_strtod(const char* str, double* d) +{ + char* endp = 0; + errno = 0; + *d = strtod(str, &endp); + if(errno || !endp || *endp) return -1; + return 0; +} + + + +int +main(int argc, char* argv[]) +{ + int fd; + double samp_rat, start_freq, end_freq; + FILE* fp; + struct iir_filter_t* fi; + + /* process commandline arguments */ + if(argc == 2 && !strcmp(argv[1], "--print-summary")) { + fputs("Generates Bode plot for a filter.\n", stdout); + return 0; + } + + if(argc != 6) { + fputs("Usage: plot_filter 'filter_desc' samp_rat start_freq end_freq out.png\n", + stderr); + return 1; + } + + fi = iir_parse(argv[1]); + if(!fi) { + fputs("Invalid filter description string.\n", stderr); + return 1; + } + + if(safe_strtod(argv[2], &samp_rat) || samp_rat < 1e-6) { + fputs("Invalid sample rate. Positive float in Hz.\n", stderr); + return 1; + } + + if(safe_strtod(argv[3], &start_freq) || start_freq < 1e-6) { + fputs("Invalid start frequency. Positive float in Hz.\n", stderr); + return 1; + } + + if(safe_strtod(argv[4], &end_freq) || end_freq < 1e-6 + || end_freq > samp_rat || end_freq < start_freq) + { + fputs("Invalid end frequency. Positive float in Hz, less than sample\n" + "rate, but greater than start frequency.\n", stderr); + return 1; + } + + /* create temporary file for results; gnuplot will use this */ + tmp_fname = strdup("/tmp/libiir-plot_filter.data.XXXXXX"); + fd = mkstemp(tmp_fname); + if(fd == -1) { + perror("mkstemp"); + return 1; + } + atexit(unlink_tmpfile); + + fp = fdopen(fd, "w"); + calc_response(fp, fi, samp_rat, start_freq, end_freq); + fclose(fp); + + /* clean up (for valgrind) */ + iir_filter_free(fi); + + /* draw the plot */ + return do_plot(argv[1], samp_rat, argv[5]); +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/src/tests/run_filter.c b/src/tests/run_filter.c new file mode 100644 index 0000000..05d22a8 --- /dev/null +++ b/src/tests/run_filter.c @@ -0,0 +1,77 @@ +/* libiir/src/tests/run_filter.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#include "iir.h" + +#include +#include + + + +int +main(int argc, char* argv[]) +{ + FILE* outf, * inf; + struct iir_filter_t* iir; + double samp; + + outf = stdout; + inf = stdin; + + /* process commandline arguments */ + if(argc == 2 && !strcmp(argv[1], "--print-summary")) { + fputs("Runs an IIR filter on an input stream.\n", stdout); + return 0; + } + + switch(argc) { + case 4: + outf = fopen(argv[3], "w"); + if(!outf) { + perror(argv[3]); + return 1; + } + /* fall through */ + case 3: + inf = fopen(argv[2], "r"); + if(!inf) { + perror(argv[2]); + return 1; + } + /* fall through */ + case 2: + iir = iir_parse(argv[1]); + if(!iir) { + fputs("Invalid filter description string.\n", stderr); + return 1; + } + break; + + default: + fputs("Usage: run_filter 'filter desc' [infile [outfile]]\n", stdout); + return 1; + } + + /* run filter on our input */ + while(fscanf(inf, " %lf", &samp) == 1) { + fprintf(outf, "%f\n", iir_filter(iir, samp)); + } + + /* clean up (for valgrind) */ + if(outf != stdout) fclose(outf); + if(inf != stdin) fclose(inf); + iir_filter_free(iir); + + return 0; +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/src/tests/template b/src/tests/template new file mode 100644 index 0000000..5bee414 --- /dev/null +++ b/src/tests/template @@ -0,0 +1,39 @@ +/* libiir/src/tests/???.c + * + * Copyright: ©2010, Laurence Withers. + * Author: Laurence Withers + * License: GPLv3 +*/ + +#include "iir.h" + +#include +#include + + + +int +main(int argc, char* argv[]) +{ + int ret = 0; + + if(argc == 2 && !strcmp(argv[1], "--print-summary")) { + fputs("One line summary.\n", stdout); + return 0; + } + + if(argc == 1) { + /* empty argument list */ + } + + /* TODO */ + + return ret; +} + + + +/* options for text editors +kate: replace-trailing-space-save true; space-indent true; tab-width 4; +vim: expandtab:ts=4:sw=4 +*/ diff --git a/version b/version new file mode 100644 index 0000000..d0db080 --- /dev/null +++ b/version @@ -0,0 +1,17 @@ +# libiir/version +# +# Copyright: ©2010, Laurence Withers. +# Author: Laurence Withers +# License: GPLv3 +# + + + +# VERSION contains the full version number of the library, which is +# expected to be in 'major.minor.micro' format. +VERMAJOR=0 +VERMINOR=0 +VERMICRO=0 + +# kate: replace-trailing-space-save true; space-indent true; tab-width 4; +# vim: expandtab:ts=4:sw=4:syntax=sh