C++ Time Library and Octave .oct files - c++

Question

I am trying to write an Octave C++ .oct function that uses the linasm-1.13 library but I cannot seem to get even basic loading of tzdata from /usr/share/zoneinfo/ to work. My simple test function so far is
#include <octave/oct.h>
#include <Time.h> // the linasm-1.13 library
DEFUN_DLD ( tz, args, nargout,
"-*- texinfo -*-\n\
#deftypefn {Function File} {} tz (#var{YYYYMMDDHHMMSS})\n\
\n\
#end deftypefn" )
{
octave_value_list retval_list ;
unsigned int tz ;
const char *ny_time = "/usr/share/zoneinfo/America/New_York" ;
tz = Time::LoadTimeZone( ny_time ) ;
return retval_list ;
which, on compiling with mkoctfile, gives this error
>> mkoctfile tz.cc
tz.cc: In function ‘octave_value_list Ftz(const octave_value_list&, int)’:
tz.cc:24:34: error: cannot call member function ‘unsigned int Time::LoadTimeZone(const char*)’ without object
tz = Time::LoadTimeZone( ny_time ) ;
^
warning: mkoctfile: building exited with failure status
My understanding of this is that ny_time is not an object that is recognised, but I have tried casting ny_time as a string literal as detailed in this accepted SO answer.
I am doing things this way because the input for LoadTimeZone according to the linasm page should be a "path to tzfile, which describes required time zone." Where am I going wrong?

Answer 1

I think you have to #include "source.cc" files also, not just the #include "header.h" files. In your case, I guess you should add: #include "Time.cc" or something like that. I don't know why but this worked for me when working with Rafat's Hussain wavemin library, but I had only 4 files, it must be incredibly tedious with lots of files.
This is what I did (it's a modified version of the test code provided by Rafat with his library).
#include "wavemin.h"
#include "waveaux.h"
#include "wavemin.cc"
#include "waveaux.cc"
#include <octave/oct.h>
double ensayo();
double absmax(double *array, int N);
DEFUN_DLD(helloctave2, argv, , "Usage: hello()"){
wave_object obj;
wt_object wt;
double *inp, *out, *diff;
int N, i, J;
char *name = "db4";
obj = wave_init(name);// Initialize the wavelet
N = 14; //Length of Signal
inp = (double*)malloc(sizeof(double)* N); //Input signal
out = (double*)malloc(sizeof(double)* N);
diff = (double*)malloc(sizeof(double)* N);
//wmean = mean(temp, N);
for (i = 0; i < N; ++i) {
inp[i] = i;
}
J = 1; //Decomposition Levels
wt = wt_init(obj, "dwt", N, J);// Initialize the wavelet transform object
setDWTExtension(wt, "sym");// Options are "per" and "sym". Symmetric is the default option
setWTConv(wt, "direct");
dwt(wt, inp);// Perform DWT
//DWT output can be accessed using wt->output vector. Use wt_summary to find out how to extract appx and detail coefficients
for (i = 0; i < wt->outlength; ++i) {
octave_stdout << wt->output[i];
octave_stdout << "\n";
}
idwt(wt, out);// Perform IDWT (if needed)
// Test Reconstruction
for (i = 0; i < wt->siglength; ++i) {
diff[i] = out[i] - inp[i];
}
octave_stdout << absmax(diff, wt->siglength);
octave_stdout << "\n";
octave_value_list retval;
return retval;
}
double
absmax(double *array, int N) {
double max;
int i;
max = 0.0;
for (i = 0; i < N; ++i) {
if (fabs(array[i]) >= max) {
max = fabs(array[i]);
}
}
return max;
}