Add IPToBinarySlice function (#17)

This commmit adds IPToBinarySlice. Given a net.IP, it will return a
[]byte whose values are the binary representation of the IP.

Author: ryanfolsom

iplib.go

@@ -378,6 +378,22 @@ func IPToBigint(ip net.IP) *big.Int {
 	return z
 }
 
+// IPToBinarySlice returns the given net.IP as a []byte whose
+// values are the binary representation of the IP
+func IPToBinarySlice(ip net.IP) []byte {
+	var bits []byte
+	if EffectiveVersion(ip) == 4 {
+		ip = ForceIP4(ip)
+	}
+	for _, octet := range ip {
+		for i := 7; i >= 0; i-- {
+			bit := (octet >> i) & 1
+			bits = append(bits, bit)
+		}
+	}
+	return bits
+}
+
 // IPToBinaryString returns the given net.IP as a binary string
 func IPToBinaryString(ip net.IP) string {
 	var sa []string

iplib_test.go

@@ -1,6 +1,7 @@
 package iplib
 
 import (
+	"bytes"
 	"math/big"
 	"net"
 	"reflect"
@@ -22,13 +23,14 @@ func TestCopyIP(t *testing.T) {
 }
 
 var IPTests = []struct {
-	ipaddr net.IP
-	next   net.IP
-	prev   net.IP
-	intval uint32
-	hexval string
-	inarpa string
-	binval string
+	ipaddr   net.IP
+	next     net.IP
+	prev     net.IP
+	intval   uint32
+	hexval   string
+	inarpa   string
+	binval   string
+	binslice []byte
 }{
 	{
 		net.ParseIP("10.1.2.3"),
@@ -38,6 +40,7 @@ var IPTests = []struct {
 		"0a010203",
 		"3.2.1.10.in-addr.arpa",
 		"00001010.00000001.00000010.00000011",
+		[]byte{0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1},
 	},
 	{
 		net.ParseIP("10.1.2.255"),
@@ -47,6 +50,7 @@ var IPTests = []struct {
 		"0a0102ff",
 		"255.2.1.10.in-addr.arpa",
 		"00001010.00000001.00000010.11111111",
+		[]byte{0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1},
 	},
 	{
 		net.ParseIP("10.1.2.0"),
@@ -56,6 +60,7 @@ var IPTests = []struct {
 		"0a010200",
 		"0.2.1.10.in-addr.arpa",
 		"00001010.00000001.00000010.00000000",
+		[]byte{0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
 	},
 	{
 		net.ParseIP("255.255.255.255"),
@@ -65,6 +70,7 @@ var IPTests = []struct {
 		"ffffffff",
 		"255.255.255.255.in-addr.arpa",
 		"11111111.11111111.11111111.11111111",
+		[]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
 	},
 	{
 		net.ParseIP("0.0.0.0"),
@@ -74,6 +80,7 @@ var IPTests = []struct {
 		"00000000",
 		"0.0.0.0.in-addr.arpa",
 		"00000000.00000000.00000000.00000000",
+		[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
 	},
 }
 
@@ -113,6 +120,15 @@ func TestIPToHexString(t *testing.T) {
 	}
 }
 
+func TestIPToBinarySlice(t *testing.T) {
+	for i, tt := range IPTests {
+		b := IPToBinarySlice(tt.ipaddr)
+		if !bytes.Equal(b, tt.binslice) {
+			t.Errorf("[%d] expected %v, got %v", i, tt.binslice, b)
+		}
+	}
+}
+
 func TestIPToBinaryString(t *testing.T) {
 	for i, tt := range IPTests {
 		s := IPToBinaryString(tt.ipaddr)
@@ -183,6 +199,7 @@ var IP6Tests = []struct {
 	expand    string
 	inarpa    string
 	binval    string
+	binslice  []byte
 }{
 	{
 		"2001:db8:85a3::8a2e:370:7334",
@@ -195,6 +212,7 @@ var IP6Tests = []struct {
 		"2001:0db8:85a3:0000:0000:8a2e:0370:7334",
 		"4.3.3.7.0.7.3.0.e.2.a.8.0.0.0.0.0.0.0.0.3.a.5.8.8.b.d.0.1.0.0.2.ip6.arpa",
 		"00100000.00000001.00001101.10111000.10000101.10100011.00000000.00000000.00000000.00000000.10001010.00101110.00000011.01110000.01110011.00110100",
+		[]byte{0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0},
 	},
 	{
 		"::",
@@ -207,6 +225,7 @@ var IP6Tests = []struct {
 		"0000:0000:0000:0000:0000:0000:0000:0000",
 		"0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa",
 		"00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000.00000000",
+		[]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
 	},
 	{
 		"ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
@@ -219,6 +238,7 @@ var IP6Tests = []struct {
 		"ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
 		"f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.f.ip6.arpa",
 		"11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111.11111111",
+		[]byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
 	},
 }
 
@@ -268,6 +288,15 @@ func TestUint64ToIP6(t *testing.T) {
 	}
 }
 
+func TestIP6ToBinarySlice(t *testing.T) {
+	for i, tt := range IP6Tests {
+		b := IPToBinarySlice(net.ParseIP(tt.ipaddr))
+		if !bytes.Equal(b, tt.binslice) {
+			t.Errorf("[%d] expected %v, got %v", i, tt.binslice, b)
+		}
+	}
+}
+
 func TestIP6ToBinaryString(t *testing.T) {
 	for i, tt := range IP6Tests {
 		s := IPToBinaryString(net.ParseIP(tt.ipaddr))