Using libsierraecg

How to use the C/C++ Library

Introduction

Using the libsierraecg C/C++ library requires more work than the other language bindings, however, it is relatively straightforward. Public methods exist to read an ECG from a file and to preprocess the XML.

Prerequisites

libsierraecg uses libxml2, and compiles on Windows, Linux, and Mac OS X. In order to ensure libxml2 is used properly, users must call sierraecg_init and sierraecg_cleanup prior to and after they use the library.

#include <sierraecg.h>

int main(int argc, char* argv[])
{
   /* local variables ... */

   /* Allow the library to initialize */
   if (sierraecg_init()) abort();

   /* use the library routines sierraecg_*() */

   /* Allow the library to cleanup its dependencies */
   sierraecg_cleanup();

   return 0;
}

Preprocessing Sierra ECG XML Files

Preprocessing Sierra ECG XML files requires only one call to sierraecg_decompress:

#include <sierraecg.h>

int main(int argc, char* argv[])
{
   char output[260];
   int i;

   /* Allow the library to initialize */
   if (sierraecg_init()) abort();

   for (i = 1; i < argc; ++i) {
      memset(output, 0, sizeof(output));
      sprintf(output, "%s.decoded.xml", argv[i]);

      /* sierraecg_decompress(input, output) */
      if (sierraecg_decompress(argv[i], output)) {
         fprintf(stderr, "Errors preprocessing Sierra ECG file: %s\n",
            argv[i]);
      }
   }

   /* Allow the library to cleanup its dependencies */
   sierraecg_cleanup();

   return 0;
}

Extracting Lead Data

Extracting lead data from a Sierra ECG XML file is done like so:

#include <sierraecg.h>

int main(int argc, char* argv[])
{
   int i;

   /* Allow the library to initialize */
   if (sierraecg_init()) abort();

   for (i = 1; i < argc; ++i) {
      ecg_t ecg;

      /* sierraecg_read(input, ecg data) */
      if (sierraecg_read(argv[i], &ecg)) {
         fprintf(stderr, "Errors parsing Sierra ECG file: %s\n",
            argv[i]);
      }
      else {
         /*
          * ecg.version(char[8]):  Version, i.e. 1.03 or 1.04
          * ecg.leads(lead_t[16]): Retrieved lead data
          * ecg.valid(size_t): How many valid leads were read
          */
         int lead;
         for (lead = 0; lead < valid; ++lead) {
            /*
             * lead.name(char*): e.g. I, II, III
             * lead.samples(short[]): Lead sample data
             * lead.count(size_t): Number of samples
             * lead.duration(size_t): Total msec of the recording
             */
            fprintf(stdout, "Lead %s (%d samples, %d ms)\n",
               ecg.leads[lead].name,
               ecg.leads[lead].count,
               ecg.leads[lead].duration);
         }

         /* cleanup the ECG itself */
         sierraecg_free(&ecg);
      }
   }

   /* Allow the library to cleanup its dependencies */
   sierraecg_cleanup();

   return 0;
}