Reads both a WFDB record and annotation file at once, pairing sample amplitude to a annotation.

annot_amplitude.c

#include <stdio.h>
// #include <malloc.h>
#include <wfdb/wfdb.h>


#define USE_FMT "%s <record> :: Extracts annotations + " \
                "amplitude at annotation for a record\n"


int main (int argc, char *argv[], char **envp) {
	int sig_count, exit_code = 0;
	WFDB_Anninfo a;
	WFDB_Annotation annot, last_annot = {0};
	WFDB_Sample *v = NULL;
	WFDB_Siginfo *s = NULL;

	/******************** Initialization ********************/

	// Print environment variables
	for (char **env = envp; *env != NULL; ++env) {
		printf("%s\n", *env);
	}

	// Check argument count
	if (argc != 2) {
		fprintf(stderr, USE_FMT, argv[0]);
		exit_code = -1; goto cleanup;
	}

	// Check for signal file (get record count)
	if ((sig_count = isigopen(argv[1], NULL, 0)) < 1) {
		fprintf(stderr, "Bad return code for isigopen(%s)\n", argv[1]);
		exit_code = -1; goto cleanup;
	}

	// Allocate record size
	s = (WFDB_Siginfo *)malloc(sig_count * sizeof(WFDB_Siginfo));
	if (isigopen(argv[1], s, sig_count) != sig_count) {
		fprintf(stderr, "Couldn't extract %d records from %s sig file!\n",
			sig_count, argv[1]);
		exit_code = -1; goto cleanup;
	}

	// Allocate samples to store vectors
	v = (WFDB_Sample *)malloc(sig_count * sizeof(WFDB_Sample));

	// Configure the attribute file extension
	a.name = "atr"; a.stat = WFDB_READ;

	// Attempt to open the attribute file
	if (annopen(argv[1], &a, 1) < 0) {
		fprintf(stderr, "Couldn't open annotation file for %s\n", argv[1]);
		exit_code = -1; goto cleanup;
	}


	/******************** Parsing ********************/

	// Print column headers
	printf("Time\tSample(#)\tType\tAmplitude\tElapsed\n");

	// Move through records
	long sample_offset = 0;

	// For each annotation
	while (getann(0, &annot) == 0) {

		// Extract the timestamp (sample number)
		long timestamp = annot.time;

		// Move up to the sample at this timestamp
		while (sample_offset < timestamp) {
			if (getvec(v) < 0) {
				fprintf(stderr, "Ran out of samples before timestamp!\n");
				exit_code = -1; goto cleanup;
			}
			sample_offset++;
		}

		// Print annotation and peak
		printf("%s\t%ld\t%s", mstimstr(-(annot.time)), annot.time, annstr(annot.anntyp));

		// Extract the channel
		int channel = annot.chan;

		// Print signal in that channel
		printf("\t%8d", v[channel]);

		// Print elapsed time since last peak (hopefully the last peak was annotated)
		printf("\t%s\n", mstimstr(-(annot.time - last_annot.time)));

		last_annot = annot;
	}


cleanup:
	/* Free only defined if initialized to NULL */
	free(v); free(s);
	return exit_code;
}