GapstrReader for encodings/binary

src/netarch/gapstr.go

@@ -143,3 +143,25 @@ func (g *Gapstr) Slice(beg, end int) *Gapstr {
 	
 	return &Gapstr{chunks}
 }
+
+type GapstrReader struct {
+	g *Gapstr
+	pos int
+	GapRead bool
+}
+
+func NewGapstrReader(g *Gapstr) (*GapstrReader) {
+	return &GapstrReader{g, 0, false}
+}
+
+func (gr *GapstrReader) Read(p []byte) (n int, err error) {
+	gs := gr.g.Slice(gr.pos, gr.pos + len(p))
+	if gs.HasGaps() {
+		gr.GapRead = true
+	}
+	
+	s := []byte(gs.String())
+	nread := copy(p, s)
+	gr.pos += nread
+	return nread, nil
+}

src/netarch/gapstr_test.go

@@ -1,12 +1,21 @@
 package netarch
 
 import (
+	"fmt"
+	"runtime"
 	"testing"
 )
 
+func DUMP(a ...interface{}) {
+	_, file, line, _ := runtime.Caller(1)
+	fmt.Printf("%s:%d ", file, line)
+	fmt.Println(a...)
+}
+    
 func AssertEqual(t *testing.T, a, b interface{}) {
+	_, file, line, _ := runtime.Caller(1)
 	if a != b {
-		t.Errorf("Not equal: %#v, %#v", a, b)
+		t.Errorf("%s:%d Not equal: %#v, %#v", file, line, a, b)
 	}
 }
 
@@ -41,3 +50,26 @@ func TestGapstr(t *testing.T) {
 	
 	AssertEqual(t, g.Slice(0, 12).String(), gs[0:12])
 }
+
+func TestGapstrReader(t *testing.T) {
+	g := new(Gapstr)
+	g = g.AppendString("\xff\xff")
+	g = g.AppendGap(8)
+	g = g.AppendString("\xff\xff\xff")
+	
+	gs := g.String()
+	
+	gr := NewGapstrReader(g)
+	
+	b := make([]byte, 4)
+	for i := 0; i < 4; i += 1 {
+		beg := i*4
+		end := min((i+1) * 4, len(gs))
+		truth := gs[beg:end]
+		nread, err := gr.Read(b)
+		
+		AssertEqual(t, nread, len(truth))
+		AssertEqual(t, err, nil)
+		AssertEqual(t, string(b[:nread]), truth)
+	}
+}