Drop the write-only direction fields and the unused pattern names

frame.go

@@ -17,19 +17,14 @@ const (
 
 var crcTable = crc32.MakeTable(crc32.Castagnoli)
 
-type pattern struct {
-	name string
-	fill func([]byte)
-}
-
-var patterns = []pattern{
-	{"zeros", func(b []byte) { clear(b) }},
-	{"ones", func(b []byte) {
+var patterns = []func([]byte){
+	func(b []byte) { clear(b) },
+	func(b []byte) {
 		for i := range b {
 			b[i] = 0xff
 		}
-	}},
-	{"alt", func(b []byte) {
+	},
+	func(b []byte) {
 		for i := range b {
 			if i%2 == 0 {
 				b[i] = 0x55
@@ -37,13 +32,13 @@ var patterns = []pattern{
 				b[i] = 0xaa
 			}
 		}
-	}},
-	{"incr", func(b []byte) {
+	},
+	func(b []byte) {
 		for i := range b {
 			b[i] = byte(i)
 		}
-	}},
-	{"prbs", func(b []byte) {
+	},
+	func(b []byte) {
 		s := uint64(0x0123456789abcdef)
 		for i := range b {
 			s ^= s << 13
@@ -51,13 +46,13 @@ var patterns = []pattern{
 			s ^= s << 17
 			b[i] = byte(s)
 		}
-	}},
-	{"random", func(b []byte) {
+	},
+	func(b []byte) {
 		r := rand.New(rand.NewPCG(0xc0ffee, 0x5eed))
 		for i := range b {
 			b[i] = byte(r.Uint32())
 		}
-	}},
+	},
 }
 
 // Every pattern is laid out at full length up front with its checksum at each
@@ -88,9 +83,9 @@ func newFrameSpec(dst, src [6]byte, etherType uint16, sizes []int) *frameSpec {
 		maxSize:   maxSize,
 		maxPay:    maxSize - minFrame,
 	}
-	for _, p := range patterns {
+	for _, fill := range patterns {
 		ref := make([]byte, f.maxPay)
-		p.fill(ref)
+		fill(ref)
 		crcFor := make(map[int]uint32, len(sizes))
 		for _, s := range sizes {
 			crcFor[s] = crc32.Checksum(ref[:s-minFrame], crcTable)