[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

How can I declare an "uint8 RowVector"?

From: Roberto Vidmar
Subject: How can I declare an "uint8 RowVector"?
Date: Mon, 16 Jan 2006 09:09:17 +0100
User-agent: Mozilla Thunderbird 1.0.2 (X11/20050317)

Hi to all,

I need to read and process a binary file made of 553 byte records. Every record contains many data and, among these, 3 arrays of uint8 values. First I wrote an octave function to store every record in an octave structure using fread and uint8 convertion funcion:

RpfRecord.ret2 = uint8(fread(rpfid, 220, 'uint8'));

...but this is far to slow for my purpouses so I tried to move the reading part into a dynamic loadable function written in C++ (but I'm NOT a C++ programmer, I know only non-object oriented languages).

My C++ function opens the file, reads it, and returns a structure, at preset just a single record not yet a vector. The code follows:

#include <octave/oct.h>
#include <octave/ov-struct.h>
#include <rpf-a.h>

DEFUN_DLD (readrpf, args, ,
"Read RPF file into RPF structure.\n\
Roberto Vidmar Jannuary 2006.\n\
Last Update: 20060111.")

octave_value_list  retval;
rpf_record_t       rpf_record;
RowVector t0(40); # I know this declares an array of double, but I'm not able to declare an uint8 array.....
FILE *             rpf_fp;
int                bytesread=0;

rpf_fp=fopen("outfile.rpf.recs", "r");
bytesread=fread(&rpf_record.gpstime, 1, sizeof(rpf_record.gpstime), rpf_fp); bytesread+=fread(&rpf_record.pulsecount, 1, sizeof(rpf_record.pulsecount), rpf_fp); bytesread+=fread(&rpf_record.range, 1, sizeof(rpf_record.range), rpf_fp); bytesread+=fread(&rpf_record.intensity, 1, sizeof(rpf_record.intensity), rpf_fp); bytesread+=fread(&rpf_record.scanangle, 1, sizeof(rpf_record.scanangle), rpf_fp); bytesread+=fread(&rpf_record.roll, 1, sizeof(rpf_record.roll), rpf_fp); bytesread+=fread(&rpf_record.pitch, 1, sizeof(rpf_record.pitch), rpf_fp); bytesread+=fread(&rpf_record.heading, 1, sizeof(rpf_record.heading), rpf_fp); bytesread+=fread(&rpf_record.aircraft_lat, 1, sizeof(rpf_record.aircraft_lat), rpf_fp); bytesread+=fread(&rpf_record.aircraft_lon, 1, sizeof(rpf_record.aircraft_lon), rpf_fp); bytesread+=fread(&rpf_record.aircraft_ele, 1, sizeof(rpf_record.aircraft_ele), rpf_fp); bytesread+=fread(&rpf_record.t1, 1, sizeof(rpf_record.t1), rpf_fp); bytesread+=fread(&rpf_record.t2, 1, sizeof(rpf_record.t2), rpf_fp); bytesread+=fread(&rpf_record.t0, 1, sizeof(rpf_record.t0), rpf_fp); bytesread+=fread(&rpf_record.ret1, 1, sizeof(rpf_record.ret1), rpf_fp); bytesread+=fread(&rpf_record.ret2, 1, sizeof(rpf_record.ret2), rpf_fp);
printf("----- bytesread=%d -----\n\n", bytesread);

Octave_map stru( "Field1" , "Filed1_value"); stru.assign("gpstime", rpf_record.gpstime);

stru.assign("pulsecount", rpf_record.pulsecount);
stru.assign("range", &rpf_record.range);
stru.assign("intensity", rpf_record.intensity);
stru.assign("scanangle", rpf_record.scanangle);
stru.assign("roll", rpf_record.roll);
stru.assign("pitch", rpf_record.pitch);
stru.assign("heading", rpf_record.heading);
stru.assign("aircraft_lat", rpf_record.aircraft_lat);
stru.assign("aircraft_lon", rpf_record.aircraft_lon);
stru.assign("aircraft_ele", rpf_record.aircraft_ele);
stru.assign("t1", rpf_record.t1);
stru.assign("t2", rpf_record.t2);
  int i;
  for (i=0; i<40; i++)
stru.assign("t0", t0);
return retval;

This works and returns the first record of the file in a structure. The problem is that t0 is a....

whos return_value.t0

*** local user variables:

Prot Name        Size                     Bytes  Class
==== ====        ====                     =====  =====
 rwd return_value.t0        1x40                       320  matrix

Total is 40 elements using 320 bytes

How can I declare t0 in a way that my function will return a 40 byte uint8 vector?
And is it possible to return directly an array of structures?

Any help will be appreciated

Roberto Vidmar

Roberto Vidmar ___ __ __ OCEANOGRAFIA
/  / /__ /__    GEOFISICA
/__/ /__/ __/    SPERIMENTALE
Istituto Nazionale di Oceanografia e
di Geofisica Sperimentale
34010 Sgonico (TS) ITALY

Research Group: CARS
(Cartography And Remote Sensing)
CARS Group is certified ISO 9001:2000

Tel. +39 040 2140 336 direct
Tel. +39 040 2140 1  operator

E-mail: address@hidden

Attachment: rvidmar.vcf
Description: Vcard

reply via email to

[Prev in Thread] Current Thread [Next in Thread]