Fixes for the Maidehead locator code, and a better regression test.

6 files changed, 58 insertions, 58 deletions

diff --git a/.gitignore b/.gitignore
index b3304335..96f1aa15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,7 +28,6 @@ test_geoid
 test_json
 test_trig
 test_libgps
-test_maidenhead_locator
 # Other generated files
 gps.html
 gpscat.html
diff --git a/SConstruct b/SConstruct
index 99a5a421..4f573f71 100644
--- a/SConstruct
+++ b/SConstruct
@@ -726,7 +726,6 @@ if ncurseslibs:
 # Test programs
 test_float = env.Program('test_float', ['test_float.c'])
 test_geoid = env.Program('test_geoid', ['test_geoid.c'], parse_flags=gpslibs)
-test_maidenhead_locator = env.Program('test_maidenhead_locator', ['test_maidenhead_locator.c'], parse_flags=gpslibs)
 test_json = env.Program('test_json', ['test_json.c'], parse_flags=gpslibs)
 test_mkgmtime = env.Program('test_mkgmtime', ['test_mkgmtime.c'], parse_flags=gpslibs)
 test_trig = env.Program('test_trig', ['test_trig.c'], parse_flags=["-lm"])
@@ -735,7 +734,7 @@ test_bits = env.Program('test_bits', ['test_bits.c', "bits.c"])
 test_gpsmm = env.Program('test_gpsmm', ['test_gpsmm.cpp'], parse_flags=gpslibs)
 test_libgps = env.Program('test_libgps', ['test_libgps.c'], parse_flags=gpslibs)
 testprogs = [test_float, test_trig, test_bits, test_packet,
-             test_mkgmtime, test_geoid, test_maidenhead_locator, test_json, test_libgps]
+             test_mkgmtime, test_geoid, test_json, test_libgps]
 if cxx and env["libgpsmm"]:
     testprogs.append(test_gpsmm)
 
@@ -1009,7 +1008,6 @@ splint_table = [
     ('splint-test_packet',['test_packet.c'],'test_packet test harness', ['']),
     ('splint-test_mkgmtime',['test_mkgmtime.c'],'test_mkgmtime test harness', ['']),
     ('splint-test_geoid',['test_geoid.c'],'test_geoid test harness', ['']),
-    ('splint-test_maidenhead_locator',['test_maidenhead_locator.c'],'test_maidenhead_locator test harness', ['']),
     ('splint-test_json',['test_json.c'],'test_json test harness', ['']),
     ]
 
@@ -1128,14 +1126,10 @@ geoid_regress = Utility('geoid-regress', [test_geoid], [
     '$SRCDIR/test_geoid 37.371192 122.014965 | diff -u $SRCDIR/test/geoid.test.chk -',
     ])
 
-# Rebuild the Maidenhead Locator test
-Utility('maidenhead-locator-makeregress', [test_maidenhead_locator], [
-    '$SRCDIR/test_maidenhead_locator 37.371192 122.014965 >$SRCDIR/test/maidenhead_locator.test.chk'])
-
 # Regression-test the Maidenhead Locator
-maidenhead_locator_regress = Utility('maidenhead-locator-regress', [test_maidenhead_locator], [
-    '@echo "Testing the Maidenhead Locator..."',
-    '$SRCDIR/test_maidenhead_locator 37.371192 122.014965 | diff -u $SRCDIR/test/maidenhead_locator.test.chk -',
+maidenhead_locator_regress = Utility('maidenhead-locator-regress', [], [
+    '@echo "Testing the Maidenhead Locator conversion..."',
+    '$SRCDIR/test_maidenhead.py',
     ])
 
 # Regression-test the calendar functions
diff --git a/gpsdclient.c b/gpsdclient.c
index 5b49c0f7..d202bf3e 100644
--- a/gpsdclient.c
+++ b/gpsdclient.c
@@ -176,28 +176,45 @@ void gpsd_source_spec(const char *arg, struct fixsource_t *source)
 /*@ +observertrans -statictrans +mustfreeonly +branchstate +kepttrans @*/
 
 char *maidenhead(double n, double e)
-/* lat/lon to Maidenhead (from QGrid - http://users.pandora.be/on4qz/qgrid/) */
+/* lat/lon to Maidenhead */
 {
+    /*
+     * Specification at
+     * http://en.wikipedia.org/wiki/Maidenhead_Locator_System
+     *
+     * There's a fair amount of slop in how Maidenhead converters operate
+     * that can make it look like this one is wrong.  
+     *
+     * 1. Many return caps for paces 5 and 6 when according to the spwec
+     *    they should return smalls.
+     *
+     * 2. Some converters, including QGrid from which this code was originally
+     *    derived, add an 0.5 offset to the divided e and n just before it
+     *    is cast to integer and used for places 5 and 6. This appears to be 
+     *    intended as a round-to-nearest hack (as opposed to the implicit
+     *    round down from the cast). If I'm reading the spec right it
+     *    is not correct to do this.
+     */
     static char buf[7];
 
     int t1;
     e=e+180.0;
     t1=(int)(e/20);
-    buf[0]=(char)t1+'@';
+    buf[0]=(char)t1+'A';
     e-=(float)t1*20.0;
     t1=(int)e/2;
-    buf[2]=(char)t1+'/';
+    buf[2]=(char)t1+'0';
     e-=(float)t1*2;
-    buf[4]=(char)(int)(e*12.0+0.5)+'`';
+    buf[4]=(char)(int)(e*12.0)+'a';
 
     n=n+90.0;
     t1=(int)(n/10.0);
-    buf[1]=(char)t1+'@';
+    buf[1]=(char)t1+'A';
     n-=(float)t1*10.0;
-    buf[3]=(char)n+'/';
+    buf[3]=(char)n+'0';
     n-=(int)n;
     n*=24; // convert to 24 division
-    buf[5]=(char)(int)(n+0.5)+'`';
+    buf[5]=(char)(int)(n)+'a';
     buf[6] = '\0';
  
     return buf;
diff --git a/test/maidenhead_locator.test.chk b/test/maidenhead_locator.test.chk
deleted file mode 100644
index bea4d550..00000000
--- a/test/maidenhead_locator.test.chk
+++ /dev/null
@@ -1 +0,0 @@
- lat= 37.371192 lon= 122.014965 locator= OL06`i
diff --git a/test_maidenhead.py b/test_maidenhead.py
new file mode 100755
index 00000000..39010b62
--- /dev/null
+++ b/test_maidenhead.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+#
+# Test grid locator conversion.
+#
+# Midenhead specification at
+#       http://en.wikipedia.org/wiki/Maidenhead_Locator_System
+# Test conversions generated using
+#       http://f6fvy.free.fr/qthLocator/
+
+import sys, gps.clienthelpers
+
+errors = 0
+for (lat, lon, maidenhead, location) in [
+    (48.86471,  2.37305, "JN18eu", "Paris"),
+    (41.93498, 12.43652, "JN61fw", "Rome"),
+    (39.9771,  -75.1685, "FM29jx", "Philadelphia"),
+    (-23.4028, -50.9766, "GG46mo", "Sao Paulo"),
+    ]:
+    converted = gps.clienthelpers.maidenhead(lat, lon)
+    if converted != maidenhead:
+        print >>sys.stderr, "maidenhead test: from %s %s (%s) expected %s got %s" \
+              % (lat, lon, location, maidenhead, converted)
+    else:
+        print "%s OK" % location
+
+if errors:
+    sys.exit(1)
+else:
+    sys.exit(0)
+
diff --git a/test_maidenhead_locator.c b/test_maidenhead_locator.c
deleted file mode 100644
index ea60fa00..00000000
--- a/test_maidenhead_locator.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* test driver for the ECEF to Maidenhead Locator
- *
- * This file is Copyright (c) 2011 by the GPSD project
- * BSD terms apply: see the file COPYING in the distribution root for details. 
- *
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "gpsdclient.h"
-
-int main(int argc, char **argv)
-{
-    double lat, lon;
-
-    if (argc != 3) {
-	fprintf(stderr, "Usage: %s lat lon\n", argv[0]);
-	return 1;
-    }
-
-    lat = atof(argv[1]);
-    lon = atof(argv[2]);
-
-    if (lat > 90. || lat < -90.) {
-	fprintf(stderr, " -90 <= lat=%s(%.f) <= 90 ?\n", argv[1], lat);
-	return 1;
-    }
-
-    if (lon > 180. || lat < -180.) {
-	fprintf(stderr, " -180 <= lon=%s(%.f) <= 180 ?\n", argv[2], lon);
-	return 1;
-    }
-
-    printf(" lat= %f lon= %f locator= %s\n",
-	   lat, lon, maidenhead(lat, lon));
-
-    return 0;
-}