Add tests for LOC record String() generation and fix small problems

Added tests for the cmToM function to make sure that it's output is
correct. Modified the way the Altitude is written to a string. Previously,
if the altitude was an exact number of meters it would always be reported
with two decimal places. This is not needed. Conversely if it was not
an exact number of meters the cm were removed.

parse_test.go

@@ -386,8 +386,8 @@ func TestNSEC(t *testing.T) {
 
 func TestParseLOC(t *testing.T) {
 	lt := map[string]string{
-		"SW1A2AA.find.me.uk.	LOC	51 30 12.748 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m": "SW1A2AA.find.me.uk.\t3600\tIN\tLOC\t51 30 12.748 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m",
+		"SW1A2AA.find.me.uk.	LOC	51 30 12.748 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m": "SW1A2AA.find.me.uk.\t3600\tIN\tLOC\t51 30 12.748 N 00 07 39.611 W 0m 0.00m 0.00m 0.00m",
-		"SW1A2AA.find.me.uk.	LOC	51 0 0.0 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m": "SW1A2AA.find.me.uk.\t3600\tIN\tLOC\t51 00 0.000 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m",
+		"SW1A2AA.find.me.uk.	LOC	51 0 0.0 N 00 07 39.611 W 0.00m 0.00m 0.00m 0.00m": "SW1A2AA.find.me.uk.\t3600\tIN\tLOC\t51 00 0.000 N 00 07 39.611 W 0m 0.00m 0.00m 0.00m",
 	}
 	for i, o := range lt {
 		rr, e := NewRR(i)

types.go

@@ -160,10 +160,14 @@ const (
 	_AD = 1 << 5  // authticated data
 	_CD = 1 << 4  // checking disabled
 
-)
+	LOC_EQUATOR       = 1 << 31 // RFC 1876, Section 2.
+	LOC_PRIMEMERIDIAN = 1 << 31 // RFC 1876, Section 2.
 
-// RFC 1876, Section 2
+	LOC_HOURS   = 60 * 1000
-const _LOC_EQUATOR = 1 << 31
+	LOC_DEGREES = 60 * LOC_HOURS
+
+	LOC_ALTITUDEBASE = 100000
+)
 
 // RFC 4398, Section 2.1
 const (
@@ -783,48 +787,69 @@ func (rr *LOC) copy() RR {
 	return &LOC{*rr.Hdr.copyHeader(), rr.Version, rr.Size, rr.HorizPre, rr.VertPre, rr.Latitude, rr.Longitude, rr.Altitude}
 }
 
+// cmToM takes a cm value expressed in RFC1876 SIZE mantissa/exponent
+// format and returns a string in m (two decimals for the cm)
+func cmToM(m, e uint8) string {
+	if e < 2 {
+		if e == 1 {
+			m *= 10
+		}
+
+		return fmt.Sprintf("0.%02d", m)
+	}
+
+	s := fmt.Sprintf("%d", m)
+	for e > 2 {
+		s += "0"
+		e -= 1
+	}
+	return s
+}
+
+// String returns a string version of a LOC
 func (rr *LOC) String() string {
 	s := rr.Hdr.String()
-	// Copied from ldns
-	// Latitude
-	lat := rr.Latitude
-	north := "N"
-	if lat > _LOC_EQUATOR {
-		lat = lat - _LOC_EQUATOR
-	} else {
-		north = "S"
-		lat = _LOC_EQUATOR - lat
-	}
-	h := lat / (1000 * 60 * 60)
-	lat = lat % (1000 * 60 * 60)
-	m := lat / (1000 * 60)
-	lat = lat % (1000 * 60)
-	s += fmt.Sprintf("%02d %02d %0.3f %s ", h, m, (float32(lat) / 1000), north)
-	// Longitude
-	lon := rr.Longitude
-	east := "E"
-	if lon > _LOC_EQUATOR {
-		lon = lon - _LOC_EQUATOR
-	} else {
-		east = "W"
-		lon = _LOC_EQUATOR - lon
-	}
-	h = lon / (1000 * 60 * 60)
-	lon = lon % (1000 * 60 * 60)
-	m = lon / (1000 * 60)
-	lon = lon % (1000 * 60)
-	s += fmt.Sprintf("%02d %02d %0.3f %s ", h, m, (float32(lon) / 1000), east)
 
-	s1 := rr.Altitude / 100.00
+	lat := rr.Latitude
-	s1 -= 100000
+	ns := "N"
-	if rr.Altitude%100 == 0 {
+	if lat > LOC_EQUATOR {
-		s += fmt.Sprintf("%.2fm ", float32(s1))
+		lat = lat - LOC_EQUATOR
 	} else {
-		s += fmt.Sprintf("%.0fm ", float32(s1))
+		ns = "S"
+		lat = LOC_EQUATOR - lat
 	}
-	s += cmToString((rr.Size&0xf0)>>4, rr.Size&0x0f) + "m "
+	h := lat / LOC_DEGREES
-	s += cmToString((rr.HorizPre&0xf0)>>4, rr.HorizPre&0x0f) + "m "
+	lat = lat % LOC_DEGREES
-	s += cmToString((rr.VertPre&0xf0)>>4, rr.VertPre&0x0f) + "m"
+	m := lat / LOC_HOURS
+	lat = lat % LOC_HOURS
+	s += fmt.Sprintf("%02d %02d %0.3f %s ", h, m, (float64(lat) / 1000), ns)
+
+	lon := rr.Longitude
+	ew := "E"
+	if lon > LOC_PRIMEMERIDIAN {
+		lon = lon - LOC_PRIMEMERIDIAN
+	} else {
+		ew = "W"
+		lon = LOC_PRIMEMERIDIAN - lon
+	}
+	h = lon / LOC_DEGREES
+	lon = lon % LOC_DEGREES
+	m = lon / LOC_HOURS
+	lon = lon % LOC_HOURS
+	s += fmt.Sprintf("%02d %02d %0.3f %s ", h, m, (float64(lon) / 1000), ew)
+
+	var alt float64 = float64(rr.Altitude) / 100
+	alt -= LOC_ALTITUDEBASE
+	if rr.Altitude%100 != 0 {
+		s += fmt.Sprintf("%.2fm ", alt)
+	} else {
+		s += fmt.Sprintf("%.0fm ", alt)
+	}
+
+	s += cmToM((rr.Size&0xf0)>>4, rr.Size&0x0f) + "m "
+	s += cmToM((rr.HorizPre&0xf0)>>4, rr.HorizPre&0x0f) + "m "
+	s += cmToM((rr.VertPre&0xf0)>>4, rr.VertPre&0x0f) + "m"
+
 	return s
 }
 
@@ -1580,23 +1605,6 @@ func saltToString(s string) string {
 	return strings.ToUpper(s)
 }
 
-func cmToString(mantissa, exponent uint8) string {
-	switch exponent {
-	case 0, 1:
-		if exponent == 1 {
-			mantissa *= 10
-		}
-		return fmt.Sprintf("%.02f", float32(mantissa))
-	default:
-		s := fmt.Sprintf("%d", mantissa)
-		for i := uint8(0); i < exponent-2; i++ {
-			s += "0"
-		}
-		return s
-	}
-	panic("dns: not reached")
-}
-
 func euiToString(eui uint64, bits int) (hex string) {
 	switch bits {
 	case 64:

types_test.go

@@ -0,0 +1,42 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestCmToM(t *testing.T) {
+	s := cmToM(0, 0)
+	if s != "0.00" {
+		t.Error("0, 0")
+	}
+
+	s = cmToM(1, 0)
+	if s != "0.01" {
+		t.Error("1, 0")
+	}
+
+	s = cmToM(3, 1)
+	if s != "0.30" {
+		t.Error("3, 1")
+	}
+
+	s = cmToM(4, 2)
+	if s != "4" {
+		t.Error("4, 2")
+	}
+
+	s = cmToM(5, 3)
+	if s != "50" {
+		t.Error("5, 3")
+	}
+
+	s = cmToM(7, 5)
+	if s != "7000" {
+		t.Error("7, 5")
+	}
+
+	s = cmToM(9, 9)
+	if s != "90000000" {
+		t.Error("9, 9")
+	}
+}

zscan.go

@@ -899,9 +899,9 @@ func appendOrigin(name, origin string) string {
 func locCheckNorth(token string, latitude uint32) (uint32, bool) {
 	switch token {
 	case "n", "N":
-		return _LOC_EQUATOR + latitude, true
+		return LOC_EQUATOR + latitude, true
 	case "s", "S":
-		return _LOC_EQUATOR - latitude, true
+		return LOC_EQUATOR - latitude, true
 	}
 	return latitude, false
 }
@@ -910,9 +910,9 @@ func locCheckNorth(token string, latitude uint32) (uint32, bool) {
 func locCheckEast(token string, longitude uint32) (uint32, bool) {
 	switch token {
 	case "e", "E":
-		return _LOC_EQUATOR + longitude, true
+		return LOC_EQUATOR + longitude, true
 	case "w", "W":
-		return _LOC_EQUATOR - longitude, true
+		return LOC_EQUATOR - longitude, true
 	}
 	return longitude, false
 }