From 265674fa57ca17c81144c8742f6ba0232da4cf7c Mon Sep 17 00:00:00 2001
From: Rob Pike <r@golang.org>
Date: Thu, 2 Jul 2009 18:02:42 -0700
Subject: [PATCH] slices

R=rsc
DELTA=59  (44 added, 13 deleted, 2 changed)
OCL=31105
CL=31105
---
 src/pkg/gob/codec_test.go |  4 ++-
 src/pkg/gob/decode.go     | 53 ++++++++++++++++++++++++++++++---------
 2 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/src/pkg/gob/codec_test.go b/src/pkg/gob/codec_test.go
index 8dd252b4ce..e25a719fad 100644
--- a/src/pkg/gob/codec_test.go
+++ b/src/pkg/gob/codec_test.go
@@ -525,7 +525,7 @@ func TestScalarDecInstructions(t *testing.T) {
 }
 
 
-func TestEncode(t *testing.T) {
+func TestEndToEnd(t *testing.T) {
 	type T2 struct {
 		t string
 	}
@@ -535,6 +535,7 @@ func TestEncode(t *testing.T) {
 		a, b,c int;
 		n *[3]float;
 		strs *[2]string;
+		int64s *[]int64;
 		s string;
 		y []byte;
 		t *T2;
@@ -545,6 +546,7 @@ func TestEncode(t *testing.T) {
 		c: -5,
 		n: &[3]float{1.5, 2.5, 3.5},
 		strs: &[2]string{s1, s2},
+		int64s: &[]int64{77, 89, 123412342134},
 		s: "Now is the time",
 		y: strings.Bytes("hello, sailor"),
 		t: &T2{"this is T2"},
diff --git a/src/pkg/gob/decode.go b/src/pkg/gob/decode.go
index 8a7440b0b4..80d772fd0d 100644
--- a/src/pkg/gob/decode.go
+++ b/src/pkg/gob/decode.go
@@ -313,30 +313,54 @@ func decodeStruct(engine *decEngine, rtyp reflect.StructType, r io.Reader, p uin
 	return state.err
 }
 
-func decodeArray(atyp reflect.ArrayType, state *DecState, p uintptr, elemOp decOp, elemWid int, length int, indir, elemIndir int) os.Error {
+func decodeArrayHelper(state *DecState, p uintptr, elemOp decOp, elemWid, length, elemIndir int) os.Error {
+	instr := &decInstr{elemOp, 0, elemIndir, 0};
+	for i := 0; i < length && state.err == nil; i++ {
+		up := unsafe.Pointer(p);
+		if elemIndir > 1 {
+			up = decIndirect(up, elemIndir);
+		}
+		elemOp(instr, state, up);
+		p += uintptr(elemWid);
+	}
+	return state.err
+}
+
+func decodeArray(atyp reflect.ArrayType, state *DecState, p uintptr, elemOp decOp, elemWid, length, indir, elemIndir int) os.Error {
 	if indir > 0 {
 		up := unsafe.Pointer(p);
 		if *(*unsafe.Pointer)(up) == nil {
-			// Allocate the structure by making a slice of bytes and recording the
-			// address of the beginning of the array. TODO(rsc).
+			// Allocate the array by making a slice of bytes of the correct size
+			// and taking the address of the beginning of the array. TODO(rsc).
 			b := make([]byte, atyp.Size());
-			*(*unsafe.Pointer)(up) = unsafe.Pointer(&b[0]);
+			*(**byte)(up) = &b[0];
 		}
 		p = *(*uintptr)(up);
 	}
-	instr := &decInstr{elemOp, 0, elemIndir, 0};
 	if DecodeUint(state) != uint64(length) {
-		state.err = os.ErrorString("length mismatch in decodeArray");
+		return os.ErrorString("length mismatch in decodeArray");
 	}
-	for i := 0; i < length && state.err == nil; i++ {
+	return decodeArrayHelper(state, p, elemOp, elemWid, length, elemIndir);
+}
+
+func decodeSlice(atyp reflect.ArrayType, state *DecState, p uintptr, elemOp decOp, elemWid, indir, elemIndir int) os.Error {
+	length := int(DecodeUint(state));
+	if indir > 0 {
 		up := unsafe.Pointer(p);
-		if elemIndir > 1 {
-			up = decIndirect(up, elemIndir);
+		if *(*unsafe.Pointer)(up) == nil {
+			// Allocate the slice header.
+			*(*unsafe.Pointer)(up) = unsafe.Pointer(new(reflect.SliceHeader));
 		}
-		elemOp(instr, state, up);
-		p += uintptr(elemWid);
+		p = *(*uintptr)(up);
 	}
-	return state.err
+	// Allocate storage for the slice elements, that is, the underlying array.
+	data := make([]byte, length*atyp.Elem().Size());
+	// Always write a header at p.
+	hdrp := (*reflect.SliceHeader)(unsafe.Pointer(p));
+	hdrp.Data = uintptr(unsafe.Pointer(&data[0]));
+	hdrp.Len = uint32(length);
+	hdrp.Cap = uint32(length);
+	return decodeArrayHelper(state, hdrp.Data, elemOp, elemWid, length, elemIndir);
 }
 
 var decEngineMap = make(map[reflect.Type] *decEngine)
@@ -370,6 +394,11 @@ func decOpFor(typ reflect.Type) decOp {
 			case atyp.Elem().Kind() == reflect.Uint8Kind:
 				op = decUint8Array
 			case atyp.IsSlice():
+				elemOp := decOpFor(atyp.Elem());
+				_, elemIndir := indirect(atyp.Elem());
+				op = func(i *decInstr, state *DecState, p unsafe.Pointer) {
+					state.err = decodeSlice(atyp, state, uintptr(p), elemOp, atyp.Elem().Size(), i.indir, elemIndir);
+				};
 			case !atyp.IsSlice():
 				elemOp := decOpFor(atyp.Elem());
 				_, elemIndir := indirect(atyp.Elem());
-- 
2.48.1