ocat: NEW feature: print last N (--limit)

ocat.c

@@ -9,13 +9,6 @@
 #include "util.h"
 #include "misc.h"
 
-typedef enum {
-	GEOJSON = 0,
-	CSV,
-	JSON,
-	RAW,
-} output_type;
-
 /*
  * Print the value in a single JSON node. If string, easy. If number account for
  * what we call 'integer' types which shouldn't be printed as floats.
@@ -111,6 +104,7 @@ void usage(char *prog)
 	printf("                               YYYY-MM-DDTHH\n");
 	printf("                               YYYY-MM-DD\n");
 	printf("                               YYYY-MM\n");
+	printf("  --limit <number>	-N     last <number> points\n");
 	printf("  --format json    	-f     output format (default: JSON)\n");
 	printf("           csv                 (overrides $OCAT_FORMAT\n");
 	printf("           geojson\n");
@@ -127,7 +121,7 @@ int main(int argc, char **argv)
 {
 	char *progname = *argv, *p;
 	int c;
-	int list = 0, killdata = 0, last = 0;
+	int list = 0, killdata = 0, last = 0, limit = 0;
 	char *username = NULL, *device = NULL, *time_from = NULL, *time_to = NULL;
 	JsonNode *json, *obj, *locs;
 	time_t now, s_lo, s_hi;
@@ -164,6 +158,7 @@ int main(int argc, char **argv)
 			{ "device",	required_argument, 0, 	'd'},
 			{ "from",	required_argument, 0, 	'F'},
 			{ "to",		required_argument, 0, 	'T'},
+			{ "limit",	required_argument, 0, 	'N'},
 			{ "format",	required_argument, 0, 	'f'},
 			{ "storage",	required_argument, 0, 	'S'},
 			{ "last",	no_argument, 0, 	'L'},
@@ -173,7 +168,7 @@ int main(int argc, char **argv)
 		  };
 		int optindex = 0;
 
-		c = getopt_long(argc, argv, "hlu:d:F:T:f:KLS:", long_options, &optindex);
+		c = getopt_long(argc, argv, "hlu:d:F:T:f:KLS:N:", long_options, &optindex);
 		if (c == -1)
 			break;
 
@@ -194,6 +189,9 @@ int main(int argc, char **argv)
 			case 'F':
 				time_from = strdup(optarg);
 				break;
+			case 'N':
+				limit = atoi(optarg);
+				break;
 			case 'S':
 				strcpy(STORAGEDIR, optarg);
 				break;
@@ -277,6 +275,11 @@ int main(int argc, char **argv)
 		return (-2);
 	}
 
+	/* If no from time specified but limit, set from to this month */
+	if (limit) {
+		time_from = strdup(yyyymm(now));
+	}
+
 	if (make_times(time_from, &s_lo, time_to, &s_hi) != 1) {
 		fprintf(stderr, "%s: bad time(s) specified\n", progname);
 		return (-2);
@@ -345,6 +348,21 @@ int main(int argc, char **argv)
 		 * process each and build the JSON `obj' with an array of locations.
 		 */
 
+		if (limit) {
+			/* get a list of .rec files from lister() without time limits,
+			 * process them in reverse order */
+
+			printf("*** LIMIT %d\n", limit);
+			if ((json = lister(username, device, s_lo, s_hi)) != NULL) {
+				if ((arr = json_find_member(json, "results")) != NULL) { // get array
+					json_foreach(f, arr) {
+						reverse_locations(f->string_, obj, locs, s_lo, s_hi, (otype == RAW) ? 1 : 0, limit);
+					}
+				}
+				json_delete(json);
+			}
+		} else {
+
 			if ((json = lister(username, device, s_lo, s_hi)) != NULL) {
 				if ((arr = json_find_member(json, "results")) != NULL) { // get array
 					json_foreach(f, arr) {
@@ -355,6 +373,7 @@ int main(int argc, char **argv)
 				json_delete(json);
 			}
 		}
+	}
 
 	json_append_member(obj, "locations", locs);
 

storage.c

@@ -396,6 +396,123 @@ JsonNode *lister(char *user, char *device, time_t s_lo, time_t s_hi)
 	return (json);
 }
 
+struct jparam {
+	JsonNode *obj;
+	JsonNode *locs;
+};
+
+/*
+ * line is a single valid '*' line from a .rec file. Turn it into a JSON object.
+ * objectorize it. Is that a word? :)
+ */
+
+static JsonNode *line_to_location(char *line)
+{
+	JsonNode *json, *o, *j;
+	char *ghash;
+	char tstamp[64], *bp;
+	double lat, lon;
+	long tst;
+
+	snprintf(tstamp, 21, "%s", line);
+
+	if ((bp = strchr(line, '{')) == NULL)
+		return (NULL);
+
+	if ((json = json_decode(bp)) == NULL) {
+		return (NULL);
+	}
+
+	o = json_mkobject();
+
+	if (json_copy_to_object(o, json, FALSE) == FALSE) {
+		json_delete(o);
+		return (NULL);
+	}
+
+	lat = lon = 0.0;
+	if ((j = json_find_member(o, "lat")) != NULL) {
+		lat = j->number_;
+	}
+	if ((j = json_find_member(o, "lon")) != NULL) {
+		lon = j->number_;
+	}
+
+	ghash = geohash_encode(lat, lon, GEOHASH_PREC);
+	json_append_member(o, "ghash", json_mkstring(ghash));
+	json_append_member(o, "isorcv", json_mkstring(tstamp));
+
+	tst = 0L;
+	if ((j = json_find_member(o, "tst")) != NULL) {
+		tst = j->number_;
+	}
+	json_append_member(o, "isotst", json_mkstring(isotime(tst)));
+
+	get_geo(o, ghash);
+
+	return (o);
+}
+
+/*
+ * Invoked via tac() and cat(). Verify that line is indeed a location
+ * line from a .rec file. Then objectorize it and add to the locations
+ * JSON array and update the counter in our JSON object.
+ */
+
+static int candidate_line(char *line, void *param)
+{
+	long counter = 0L;
+	JsonNode *j, *obj, *locs, *o;
+	struct jparam *jarg = (struct jparam*)param;
+	char *bp;
+
+	obj = jarg->obj;
+	locs = jarg->locs;
+
+	if (obj == NULL || obj->tag != JSON_OBJECT)
+		return (-1);
+
+	/* Do we have candidate lines? */
+	if ((bp = strstr(line, "Z\t* ")) == NULL) {	/* Not a location line */
+		return (0);
+	}
+
+	if ((bp = strrchr(bp, '\t')) == NULL) {
+		return (0);
+	}
+
+	/* Initialize our counter to what the JSON obj currently has */
+	if ((j = json_find_member(obj, "count")) != NULL) {
+		counter = j->number_;
+		json_delete(j);
+	}
+
+	// fprintf(stderr, "-->[%s]\n", line);
+
+	if ((o = line_to_location(line)) != NULL) {
+		json_append_element(locs, o);
+		++counter;
+	}
+
+	/* Add the (possibly) incremented counter back into `obj' */
+	json_append_member(obj, "count", json_mknumber(counter));
+	return (1);
+}
+
+void reverse_locations(char *filename, JsonNode *obj, JsonNode *arr, time_t s_lo, time_t s_hi, int rawmode, int limit)
+{
+	int rc;
+	struct jparam jarg;
+
+	if (obj == NULL || obj->tag != JSON_OBJECT)
+		return;
+
+	jarg.obj = obj;
+	jarg.locs = arr;
+
+	rc = tac(filename, limit, candidate_line, &jarg);
+}
+
 /*
  * Read the file at `filename' (- is stdin) and store location
  * objects at the JSON array `arr`. `obj' is a JSON object which

storage.h

@@ -4,9 +4,16 @@
 #include <time.h>
 #include "json.h"
 
+typedef enum {
+	GEOJSON = 0,
+	CSV,
+	JSON,
+	RAW,
+} output_type;
 
 JsonNode *lister(char *username, char *device, time_t s_lo, time_t s_hi);
 void locations(char *filename, JsonNode *obj, JsonNode *arr, time_t s_lo, time_t s_hi, int rawmode);
+void reverse_locations(char *filename, JsonNode *obj, JsonNode *arr, time_t s_lo, time_t s_hi, int rawmode, int limit);
 int make_times(char *time_from, time_t *s_lo, char *time_to, time_t *s_to);
 JsonNode *geo_json(JsonNode *json);
 JsonNode *kill_datastore(char *username, char *device);