splitting up go specific code. too much for one file IMO. more progress. almost done with structs.

9 files changed, 503 insertions, 269 deletions

diff --git a/nexgb/xgbgen/expression.go b/nexgb/xgbgen/expression.go
index 7099c25..a975320 100644
--- a/nexgb/xgbgen/expression.go
+++ b/nexgb/xgbgen/expression.go
@@ -13,6 +13,34 @@ type Expression interface {
 	Initialize(p *Protocol)
 }
 
+// Function is a custom expression not found in the XML. It's simply used
+// to apply a function named in 'Name' to the Expr expression.
+type Function struct {
+	Name string
+	Expr Expression
+}
+
+func (e *Function) Concrete() bool {
+	return false
+}
+
+func (e *Function) Eval() uint {
+	log.Fatalf("Cannot evaluate a 'Function'. It is not concrete.")
+	panic("unreachable")
+}
+
+func (e *Function) Reduce(prefix, fun string) string {
+	return fmt.Sprintf("%s(%s)", e.Name, e.Expr.Reduce(prefix, fun))
+}
+
+func (e *Function) String() string {
+	return e.Reduce("", "")
+}
+
+func (e *Function) Initialize(p *Protocol) {
+	e.Expr.Initialize(p)
+}
+
 type BinaryOp struct {
 	Op    string
 	Expr1 Expression
diff --git a/nexgb/xgbgen/field.go b/nexgb/xgbgen/field.go
index ed113e0..0f2323e 100644
--- a/nexgb/xgbgen/field.go
+++ b/nexgb/xgbgen/field.go
@@ -1,5 +1,10 @@
 package main
 
+import (
+	"fmt"
+	"log"
+)
+
 type Field interface {
 	Initialize(p *Protocol)
 	SrcName() string
@@ -8,6 +13,7 @@ type Field interface {
 
 	Define(c *Context)
 	Read(c *Context)
+	Write(c *Context)
 }
 
 func (pad *PadField) Initialize(p *Protocol) {}
@@ -66,8 +72,31 @@ func (f *ListField) XmlName() string {
 	return f.xmlName
 }
 
+// func (f *ListField) Size() Size { 
+	// return newExpressionSize(f.LengthExpr).Multiply(f.Type.Size()) 
+// } 
+
 func (f *ListField) Size() Size {
-	return newExpressionSize(f.LengthExpr).Multiply(f.Type.Size())
+	simpleLen := &Function{
+		Name: "pad",
+		Expr: newBinaryOp("*", f.LengthExpr, f.Type.Size().Expression),
+	}
+
+	switch f.Type.(type) {
+	case *Struct:
+		sizeFun := &Function{
+			Name: fmt.Sprintf("%sListSize", f.Type.SrcName()),
+			Expr: &FieldRef{Name: f.SrcName()},
+		}
+		return newExpressionSize(sizeFun)
+	case *Base:
+		return newExpressionSize(simpleLen)
+	case *Resource:
+		return newExpressionSize(simpleLen)
+	default:
+		log.Fatalf("Cannot compute list size with type '%T'.", f.Type)
+	}
+	panic("unreachable")
 }
 
 func (f *ListField) Initialize(p *Protocol) {
diff --git a/nexgb/xgbgen/go.go b/nexgb/xgbgen/go.go
index 014b76b..11e413b 100644
--- a/nexgb/xgbgen/go.go
+++ b/nexgb/xgbgen/go.go
@@ -1,10 +1,5 @@
 package main
 
-import (
-	"fmt"
-	"log"
-)
-
 // xgbResourceIdName is the name of the type used for all resource identifiers.
 // As of right now, it needs to be declared somewhere manually.
 var xgbGenResourceIdName = "Id"
@@ -92,173 +87,6 @@ func (td *TypeDef) Define(c *Context) {
 	c.Putln("")
 }
 
-// Struct types
-func (s *Struct) Define(c *Context) {
-	c.Putln("// '%s' struct definition", s.SrcName())
-	c.Putln("// Size: %s", s.Size())
-	c.Putln("type %s struct {", s.SrcName())
-	for _, field := range s.Fields {
-		field.Define(c)
-	}
-	c.Putln("}")
-	c.Putln("")
-
-	// Write function that reads bytes and produces this struct.
-	s.Read(c)
-
-	// Write function that reads a list of this structs.
-	s.ReadList(c)
-
-	// Write function that writes bytes given this struct.
-	s.Write(c)
-
-	// Write function that writes a list of this struct.
-	s.WriteList(c)
-}
-
-// Read for a struct creates a function 'NewStructName' that takes a byte
-// slice and produces TWO values: an instance of 'StructName' and the number
-// of bytes read from the byte slice.
-// 'NewStructName' should only be used to read raw reply data from the wire.
-func (s *Struct) Read(c *Context) {
-	c.Putln("// Struct read %s", s.SrcName())
-	c.Putln("func New%s(buf []byte) (%s, int) {", s.SrcName(), s.SrcName())
-
-	c.Putln("v := %s{}", s.SrcName())
-	c.Putln("b := 0")
-	c.Putln("consumed := 0")
-	c.Putln("consumed = 0 + consumed // no-op") // dirty hack for a no-op
-	c.Putln("")
-	for _, field := range s.Fields {
-		field.Read(c)
-	}
-	c.Putln("return v, b")
-
-	c.Putln("}")
-	c.Putln("")
-}
-
-// ReadList for a struct creates a function 'ReadStructNameList' that takes
-// a byte slice and a length and produces TWO values: an slice of StructName 
-// and the number of bytes read from the byte slice.
-func (s *Struct) ReadList(c *Context) {
-	c.Putln("// Struct list read %s", s.SrcName())
-	c.Putln("func Read%sList(buf []byte, length int) ([]%s, int) {",
-		s.SrcName(), s.SrcName())
-
-	c.Putln("v := make([]%s, length)", s.SrcName())
-	c.Putln("b := 0")
-	c.Putln("consumed := 0")
-	c.Putln("consumed = 0 + consumed // no-op") // dirty hack for a no-op
-	c.Putln("for i := 0; i < length; i++ {")
-	c.Putln("v[i], consumed = New%s(buf[b:])", s.SrcName())
-	c.Putln("b += consumed")
-	c.Putln("}")
-
-	c.Putln("return v, pad(b)")
-
-	c.Putln("}")
-	c.Putln("")
-}
-
-func (s *Struct) Write(c *Context) {
-	c.Putln("// Struct write %s", s.SrcName())
-	c.Putln("")
-}
-
-func (s *Struct) WriteList(c *Context) {
-	c.Putln("// Write struct list %s", s.SrcName())
-	c.Putln("")
-}
-
-// Union types
-func (u *Union) Define(c *Context) {
-	c.Putln("// Union definition %s", u.SrcName())
-}
-
-func (u *Union) Read(c *Context, prefix string) {
-	c.Putln("// Union read %s", u.SrcName())
-}
-
-func (u *Union) Write(c *Context, prefix string) {
-	c.Putln("// Union write %s", u.SrcName())
-}
-
-// Event types
-func (e *Event) Define(c *Context) {
-	c.Putln("// Event definition %s (%d)", e.SrcName(), e.Number)
-}
-
-func (e *Event) Read(c *Context, prefix string) {
-	c.Putln("// Event read %s", e.SrcName())
-}
-
-func (e *Event) Write(c *Context, prefix string) {
-	c.Putln("// Event write %s", e.SrcName())
-}
-
-// EventCopy types
-func (e *EventCopy) Define(c *Context) {
-	c.Putln("// EventCopy definition %s (%d)", e.SrcName(), e.Number)
-	c.Putln("")
-	c.Putln("const %s = %d", e.SrcName(), e.Number)
-	c.Putln("")
-	c.Putln("type %s %s", e.EvType(), e.Old.(*Event).EvType())
-	c.Putln("")
-	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.EvType())
-	c.Putln("return (%s)(New%s(buf))", e.EvType(), e.Old.SrcName())
-	c.Putln("}")
-	c.Putln("")
-	c.Putln("func (ev %s) ImplementsEvent() { }", e.EvType())
-	c.Putln("")
-	c.Putln("func (ev %s) Bytes() []byte {", e.EvType())
-	c.Putln("return (%s)(ev).Bytes()", e.Old.(*Event).EvType())
-	c.Putln("}")
-	c.Putln("")
-	c.Putln("func init() {")
-	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.SrcName())
-	c.Putln("}")
-	c.Putln("")
-}
-
-// Error types
-func (e *Error) Define(c *Context) {
-	c.Putln("// Error definition %s (%d)", e.SrcName(), e.Number)
-	c.Putln("")
-}
-
-func (e *Error) Read(c *Context, prefix string) {
-	c.Putln("// Error read %s", e.SrcName())
-}
-
-func (e *Error) Write(c *Context, prefix string) {
-	c.Putln("// Error write %s", e.SrcName())
-}
-
-// ErrorCopy types
-func (e *ErrorCopy) Define(c *Context) {
-	c.Putln("// ErrorCopy definition %s (%d)", e.SrcName(), e.Number)
-	c.Putln("")
-	c.Putln("const %s = %d", e.ErrConst(), e.Number)
-	c.Putln("")
-	c.Putln("type %s %s", e.ErrType(), e.Old.(*Error).ErrType())
-	c.Putln("")
-	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.ErrType())
-	c.Putln("return (%s)(New%s(buf))", e.ErrType(), e.Old.SrcName())
-	c.Putln("}")
-	c.Putln("")
-	c.Putln("func (err %s) ImplementsError() { }", e.ErrType())
-	c.Putln("")
-	c.Putln("func (err %s) Bytes() []byte {", e.ErrType())
-	c.Putln("return (%s)(err).Bytes()", e.Old.(*Error).ErrType())
-	c.Putln("}")
-	c.Putln("")
-	c.Putln("func init() {")
-	c.Putln("newErrorFuncs[%d] = New%s", e.Number, e.SrcName())
-	c.Putln("}")
-	c.Putln("")
-}
-
 // Field definitions, reads and writes.
 
 // Pad fields
@@ -268,143 +96,80 @@ func (f *PadField) Define(c *Context) {
 
 func (f *PadField) Read(c *Context) {
 	c.Putln("b += %s // padding", f.Size())
-	c.Putln("")
 }
 
-// Single fields
-func (f *SingleField) Define(c *Context) {
-	c.Putln("%s %s", f.SrcName(), f.Type.SrcName())
-}
-
-func ReadSimpleSingleField(c *Context, name string, typ Type) {
-	switch t := typ.(type) {
-	case *Resource:
-		c.Putln("%s = get32(buf[b:])", name)
-	case *TypeDef:
-		switch t.Size().Eval() {
-		case 1:
-			c.Putln("%s = %s(buf[b])", name, t.SrcName())
-		case 2:
-			c.Putln("%s = %s(get16(buf[b:]))", name, t.SrcName())
-		case 4:
-			c.Putln("%s = %s(get32(buf[b:]))", name, t.SrcName())
-		case 8:
-			c.Putln("%s = %s(get64(buf[b:]))", name, t.SrcName())
-		}
-	case *Base:
-		var val string
-		switch t.Size().Eval() {
-		case 1:
-			val = fmt.Sprintf("buf[b]")
-		case 2:
-			val = fmt.Sprintf("get16(buf[b:])")
-		case 4:
-			val = fmt.Sprintf("get32(buf[b:])")
-		case 8:
-			val = fmt.Sprintf("get64(buf[b:])")
-		}
-
-		// We need to convert base types if they aren't uintXX or byte
-		ty := t.SrcName()
-		if ty != "byte" && ty != "uint16" && ty != "uint32" && ty != "uint64" {
-			val = fmt.Sprintf("%s(%s)", ty, val)
-		}
-		c.Putln("%s = %s", name, val)
-	default:
-		log.Fatalf("Cannot read field '%s' as a simple field with %T type.",
-			name, typ)
-	}
-
-	c.Putln("b += %s", typ.Size())
-}
-
-func (f *SingleField) Read(c *Context) {
-	switch t := f.Type.(type) {
-	case *Resource:
-		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
-	case *TypeDef:
-		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
-	case *Base:
-		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
-	case *Struct:
-		c.Putln("v.%s, consumed = New%s(buf[b:])", f.SrcName(), t.SrcName())
-		c.Putln("b += consumed")
-		c.Putln("")
-	default:
-		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
-	}
-}
-
-// List fields
-func (f *ListField) Define(c *Context) {
-	c.Putln("%s []%s // length: %s",
-		f.SrcName(), f.Type.SrcName(), f.Size())
-}
-
-func (f *ListField) Read(c *Context) {
-	switch t := f.Type.(type) {
-	case *Resource:
-		length := f.LengthExpr.Reduce("v.", "")
-		c.Putln("v.%s = make([]Id, %s)", f.SrcName(), length)
-		c.Putln("for i := 0; i < %s; i++ {", length)
-		ReadSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
-		c.Putln("}")
-		c.Putln("")
-	case *Base:
-		length := f.LengthExpr.Reduce("v.", "")
-		c.Putln("v.%s = make([]%s, %s)", f.SrcName(), t.SrcName(), length)
-		c.Putln("for i := 0; i < %s; i++ {", length)
-		ReadSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
-		c.Putln("}")
-		c.Putln("")
-	case *Struct:
-		c.Putln("v.%s, consumed = Read%sList(buf[b:], %s)",
-			f.SrcName(), t.SrcName(), f.LengthExpr.Reduce("v.", ""))
-		c.Putln("b += consumed")
-		c.Putln("")
-	default:
-		log.Fatalf("Cannot read list field '%s' with %T type.",
-			f.XmlName(), f.Type)
-	}
+func (f *PadField) Write(c *Context) {
+	c.Putln("b += %s // padding", f.Size())
 }
 
 // Local fields
 func (f *LocalField) Define(c *Context) {
 	c.Putln("// local field: %s %s", f.SrcName(), f.Type.SrcName())
+	panic("todo")
 }
 
 func (f *LocalField) Read(c *Context) {
 	c.Putln("// reading local field: %s (%s) :: %s",
 		f.SrcName(), f.Size(), f.Type.SrcName())
+	panic("todo")
+}
+
+func (f *LocalField) Write(c *Context) {
+	c.Putln("// writing local field: %s (%s) :: %s",
+		f.SrcName(), f.Size(), f.Type.SrcName())
+	panic("todo")
 }
 
 // Expr fields
 func (f *ExprField) Define(c *Context) {
 	c.Putln("// expression field: %s %s (%s)",
 		f.SrcName(), f.Type.SrcName(), f.Expr)
+	panic("todo")
 }
 
 func (f *ExprField) Read(c *Context) {
 	c.Putln("// reading expression field: %s (%s) (%s) :: %s",
 		f.SrcName(), f.Size(), f.Expr, f.Type.SrcName())
+	panic("todo")
+}
+
+func (f *ExprField) Write(c *Context) {
+	c.Putln("// writing expression field: %s (%s) (%s) :: %s",
+		f.SrcName(), f.Size(), f.Expr, f.Type.SrcName())
+	panic("todo")
 }
 
 // Value field
 func (f *ValueField) Define(c *Context) {
 	c.Putln("// valueparam field: type: %s, mask name: %s, list name: %s",
 		f.MaskType.SrcName(), f.MaskName, f.ListName)
+	panic("todo")
 }
 
 func (f *ValueField) Read(c *Context) {
 	c.Putln("// reading valueparam: type: %s, mask name: %s, list name: %s",
 		f.MaskType.SrcName(), f.MaskName, f.ListName)
+	panic("todo")
+}
+
+func (f *ValueField) Write(c *Context) {
+	c.Putln("// writing valueparam: type: %s, mask name: %s, list name: %s",
+		f.MaskType.SrcName(), f.MaskName, f.ListName)
+	panic("todo")
 }
 
 // Switch field
 func (f *SwitchField) Define(c *Context) {
 	c.Putln("// switch field: %s (%s)", f.Name, f.Expr)
+	panic("todo")
 }
 
 func (f *SwitchField) Read(c *Context) {
 	c.Putln("// reading switch field: %s (%s)", f.Name, f.Expr)
+	panic("todo")
+}
+
+func (f *SwitchField) Write(c *Context) {
+	c.Putln("// writing switch field: %s (%s)", f.Name, f.Expr)
+	panic("todo")
 }
diff --git a/nexgb/xgbgen/go_error.go b/nexgb/xgbgen/go_error.go
new file mode 100644
index 0000000..0cb77cc
--- /dev/null
+++ b/nexgb/xgbgen/go_error.go
@@ -0,0 +1,39 @@
+package main
+
+// Error types
+func (e *Error) Define(c *Context) {
+	c.Putln("// Error definition %s (%d)", e.SrcName(), e.Number)
+	c.Putln("")
+}
+
+func (e *Error) Read(c *Context, prefix string) {
+	c.Putln("// Error read %s", e.SrcName())
+}
+
+func (e *Error) Write(c *Context, prefix string) {
+	c.Putln("// Error write %s", e.SrcName())
+}
+
+// ErrorCopy types
+func (e *ErrorCopy) Define(c *Context) {
+	c.Putln("// ErrorCopy definition %s (%d)", e.SrcName(), e.Number)
+	c.Putln("")
+	c.Putln("const %s = %d", e.ErrConst(), e.Number)
+	c.Putln("")
+	c.Putln("type %s %s", e.ErrType(), e.Old.(*Error).ErrType())
+	c.Putln("")
+	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.ErrType())
+	c.Putln("return (%s)(New%s(buf))", e.ErrType(), e.Old.SrcName())
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("func (err %s) ImplementsError() { }", e.ErrType())
+	c.Putln("")
+	c.Putln("func (err %s) Bytes() []byte {", e.ErrType())
+	c.Putln("return (%s)(err).Bytes()", e.Old.(*Error).ErrType())
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("func init() {")
+	c.Putln("newErrorFuncs[%d] = New%s", e.Number, e.SrcName())
+	c.Putln("}")
+	c.Putln("")
+}
diff --git a/nexgb/xgbgen/go_event.go b/nexgb/xgbgen/go_event.go
new file mode 100644
index 0000000..d91fd7a
--- /dev/null
+++ b/nexgb/xgbgen/go_event.go
@@ -0,0 +1,38 @@
+package main
+
+// Event types
+func (e *Event) Define(c *Context) {
+	c.Putln("// Event definition %s (%d)", e.SrcName(), e.Number)
+}
+
+func (e *Event) Read(c *Context, prefix string) {
+	c.Putln("// Event read %s", e.SrcName())
+}
+
+func (e *Event) Write(c *Context, prefix string) {
+	c.Putln("// Event write %s", e.SrcName())
+}
+
+// EventCopy types
+func (e *EventCopy) Define(c *Context) {
+	c.Putln("// EventCopy definition %s (%d)", e.SrcName(), e.Number)
+	c.Putln("")
+	c.Putln("const %s = %d", e.SrcName(), e.Number)
+	c.Putln("")
+	c.Putln("type %s %s", e.EvType(), e.Old.(*Event).EvType())
+	c.Putln("")
+	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.EvType())
+	c.Putln("return (%s)(New%s(buf))", e.EvType(), e.Old.SrcName())
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("func (ev %s) ImplementsEvent() { }", e.EvType())
+	c.Putln("")
+	c.Putln("func (ev %s) Bytes() []byte {", e.EvType())
+	c.Putln("return (%s)(ev).Bytes()", e.Old.(*Event).EvType())
+	c.Putln("}")
+	c.Putln("")
+	c.Putln("func init() {")
+	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.SrcName())
+	c.Putln("}")
+	c.Putln("")
+}
diff --git a/nexgb/xgbgen/go_list.go b/nexgb/xgbgen/go_list.go
new file mode 100644
index 0000000..03da22e
--- /dev/null
+++ b/nexgb/xgbgen/go_list.go
@@ -0,0 +1,75 @@
+package main
+
+import (
+	"fmt"
+	"log"
+)
+
+// List fields
+func (f *ListField) Define(c *Context) {
+	c.Putln("%s []%s // size: %s",
+		f.SrcName(), f.Type.SrcName(), f.Size())
+}
+
+func (f *ListField) Read(c *Context) {
+	c.Putln("")
+
+	switch t := f.Type.(type) {
+	case *Resource:
+		length := f.LengthExpr.Reduce("v.", "")
+		c.Putln("v.%s = make([]Id, %s)", f.SrcName(), length)
+		c.Putln("for i := 0; i < %s; i++ {", length)
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
+		c.Putln("}")
+		c.Putln("b = pad(b)")
+	case *Base:
+		length := f.LengthExpr.Reduce("v.", "")
+		c.Putln("v.%s = make([]%s, %s)", f.SrcName(), t.SrcName(), length)
+		if t.SrcName() == "byte" {
+			c.Putln("copy(v.%s[:%s], buf[b:])", f.SrcName(), length)
+			c.Putln("b += pad(%s)", length)
+		} else {
+			c.Putln("for i := 0; i < %s; i++ {", length)
+			ReadSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
+			c.Putln("}")
+			c.Putln("b = pad(b)")
+		}
+	case *Struct:
+		c.Putln("v.%s = make([]%s, %s)",
+			f.SrcName(), t.SrcName(), f.LengthExpr.Reduce("v.", ""))
+		c.Putln("b += Read%sList(buf[b:], v.%s)", t.SrcName(), f.SrcName())
+	default:
+		log.Fatalf("Cannot read list field '%s' with %T type.",
+			f.XmlName(), f.Type)
+	}
+}
+
+func (f *ListField) Write(c *Context) {
+	c.Putln("")
+
+	switch t := f.Type.(type) {
+	case *Resource:
+		length := f.LengthExpr.Reduce("v.", "")
+		c.Putln("for i := 0; i < %s; i++", length)
+		WriteSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
+		c.Putln("}")
+		c.Putln("b = pad(b)")
+	case *Base:
+		length := f.LengthExpr.Reduce("v.", "")
+		if t.SrcName() == "byte" {
+			c.Putln("copy(buf[b:], v.%s[:%s])", f.SrcName(), length)
+			c.Putln("b += pad(%s)", length)
+		} else {
+			c.Putln("for i := 0; i < %s; i++ {", length)
+			WriteSimpleSingleField(c, fmt.Sprintf("v.%s[i]", f.SrcName()), t)
+			c.Putln("}")
+			c.Putln("b = pad(b)")
+		}
+	case *Struct:
+		c.Putln("b += %sListBytes(buf[b:], v.%s)", t.SrcName(), f.SrcName())
+	default:
+		log.Fatalf("Cannot read list field '%s' with %T type.",
+			f.XmlName(), f.Type)
+	}
+}
+
diff --git a/nexgb/xgbgen/go_single_field.go b/nexgb/xgbgen/go_single_field.go
new file mode 100644
index 0000000..3c354e7
--- /dev/null
+++ b/nexgb/xgbgen/go_single_field.go
@@ -0,0 +1,138 @@
+package main
+
+import (
+	"fmt"
+	"log"
+)
+
+func (f *SingleField) Define(c *Context) {
+	c.Putln("%s %s", f.SrcName(), f.Type.SrcName())
+}
+
+func ReadSimpleSingleField(c *Context, name string, typ Type) {
+	switch t := typ.(type) {
+	case *Resource:
+		c.Putln("%s = get32(buf[b:])", name)
+	case *TypeDef:
+		switch t.Size().Eval() {
+		case 1:
+			c.Putln("%s = %s(buf[b])", name, t.SrcName())
+		case 2:
+			c.Putln("%s = %s(get16(buf[b:]))", name, t.SrcName())
+		case 4:
+			c.Putln("%s = %s(get32(buf[b:]))", name, t.SrcName())
+		case 8:
+			c.Putln("%s = %s(get64(buf[b:]))", name, t.SrcName())
+		}
+	case *Base:
+		var val string
+		switch t.Size().Eval() {
+		case 1:
+			val = fmt.Sprintf("buf[b]")
+		case 2:
+			val = fmt.Sprintf("get16(buf[b:])")
+		case 4:
+			val = fmt.Sprintf("get32(buf[b:])")
+		case 8:
+			val = fmt.Sprintf("get64(buf[b:])")
+		}
+
+		// We need to convert base types if they aren't uintXX or byte
+		ty := t.SrcName()
+		if ty != "byte" && ty != "uint16" && ty != "uint32" && ty != "uint64" {
+			val = fmt.Sprintf("%s(%s)", ty, val)
+		}
+		c.Putln("%s = %s", name, val)
+	default:
+		log.Fatalf("Cannot read field '%s' as a simple field with %T type.",
+			name, typ)
+	}
+
+	c.Putln("b += %s", typ.Size())
+}
+
+func (f *SingleField) Read(c *Context) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *TypeDef:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *Base:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *Struct:
+		c.Putln("v.%s = %s{}", f.SrcName(), t.SrcName())
+		c.Putln("b += Read%s(buf[b:], &v.%s)", t.SrcName(), f.SrcName())
+		c.Putln("")
+	default:
+		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
+	}
+}
+
+func WriteSimpleSingleField(c *Context, name string, typ Type) {
+	switch t := typ.(type) {
+	case *Resource:
+		c.Putln("put32(buf[b:], uint32(%s))", name)
+	case *TypeDef:
+		switch t.Size().Eval() {
+		case 1:
+			c.Putln("buf[b] = byte(%s)", name)
+		case 2:
+			c.Putln("put16(buf[b:], uint16(%s))", name)
+		case 4:
+			c.Putln("put32(buf[b:], uint32(%s))", name)
+		case 8:
+			c.Putln("put64(buf[b:], uint64(%s))", name)
+		}
+	case *Base:
+		switch t.Size().Eval() {
+		case 1:
+			if t.SrcName() != "byte" {
+				c.Putln("buf[b] = byte(%s)", name)
+			} else {
+				c.Putln("buf[b] = %s", name)
+			}
+		case 2:
+			if t.SrcName() != "uint16" {
+				c.Putln("put16(buf[b:], uint16(%s))", name)
+			} else {
+				c.Putln("put16(buf[b:], %s)", name)
+			}
+		case 4:
+			if t.SrcName() != "uint32" {
+				c.Putln("put32(buf[b:], uint32(%s))", name)
+			} else {
+				c.Putln("put32(buf[b:], %s)", name)
+			}
+		case 8:
+			if t.SrcName() != "uint64" {
+				c.Putln("put64(buf[b:], uint64(%s))", name)
+			} else {
+				c.Putln("put64(buf[b:], %s)", name)
+			}
+		}
+	default:
+		log.Fatalf("Cannot read field '%s' as a simple field with %T type.",
+			name, typ)
+	}
+
+	c.Putln("b += %s", typ.Size())
+}
+
+func (f *SingleField) Write(c *Context) {
+	switch t := f.Type.(type) {
+	case *Resource:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *TypeDef:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *Base:
+		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *Struct:
+		c.Putln("{")
+		c.Putln("structBytes := v.%s.Bytes()", f.SrcName())
+		c.Putln("copy(buf[b:], structBytes)")
+		c.Putln("b += len(structBytes)")
+		c.Putln("}")
+	default:
+		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
+	}
+}
diff --git a/nexgb/xgbgen/go_struct.go b/nexgb/xgbgen/go_struct.go
new file mode 100644
index 0000000..6925c88
--- /dev/null
+++ b/nexgb/xgbgen/go_struct.go
@@ -0,0 +1,107 @@
+package main
+
+func (s *Struct) Define(c *Context) {
+	c.Putln("// '%s' struct definition", s.SrcName())
+	c.Putln("// Size: %s", s.Size())
+	c.Putln("type %s struct {", s.SrcName())
+	for _, field := range s.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Write function that reads bytes and produces this struct.
+	s.Read(c)
+
+	// Write function that reads a list of this structs.
+	s.ReadList(c)
+
+	// Write function that writes bytes given this struct.
+	s.Write(c)
+
+	// Write function that writes a list of this struct.
+	s.WriteList(c)
+
+	// Write function that computes the size of a list of these structs.
+	s.WriteListSize(c)
+}
+
+// Read for a struct creates a function 'ReadStructName' that takes a source 
+// byte slice (i.e., the buffer) and a destination struct, and returns
+// the number of bytes read off the buffer.
+// 'ReadStructName' should only be used to read raw reply data from the wire.
+func (s *Struct) Read(c *Context) {
+	c.Putln("// Struct read %s", s.SrcName())
+	c.Putln("func Read%s(buf []byte, v *%s) int {", s.SrcName(), s.SrcName())
+
+	c.Putln("b := 0")
+	c.Putln("")
+	for _, field := range s.Fields {
+		field.Read(c)
+	}
+	c.Putln("return b")
+
+	c.Putln("}")
+	c.Putln("")
+}
+
+// ReadList for a struct creates a function 'ReadStructNameList' that takes
+// a source (i.e., the buffer) byte slice, and a destination slice and returns 
+// the number of bytes read from the byte slice.
+func (s *Struct) ReadList(c *Context) {
+	c.Putln("// Struct list read %s", s.SrcName())
+	c.Putln("func Read%sList(buf []byte, dest []%s) int {",
+		s.SrcName(), s.SrcName())
+
+	c.Putln("b := 0")
+	c.Putln("for i := 0; i < len(dest); i++ {")
+	c.Putln("dest[i] = %s{}", s.SrcName())
+	c.Putln("b += Read%s(buf[b:], &dest[i])", s.SrcName())
+	c.Putln("}")
+
+	c.Putln("return pad(b)")
+
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (s *Struct) Write(c *Context) {
+	c.Putln("// Struct write %s", s.SrcName())
+	c.Putln("func (v %s) Bytes() []byte {", s.SrcName())
+	c.Putln("buf := make([]byte, %s)", s.Size().Reduce("s.", ""))
+	c.Putln("b := 0")
+	c.Putln("")
+	for _, field := range s.Fields {
+		field.Write(c)
+	}
+	c.Putln("return buf")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (s *Struct) WriteList(c *Context) {
+	c.Putln("// Write struct list %s", s.SrcName())
+	c.Putln("func %sListBytes(buf []byte, list []%s) int {",
+		s.SrcName(), s.SrcName())
+	c.Putln("b := 0")
+	c.Putln("var structBytes []byte")
+	c.Putln("for _, item := range list {")
+	c.Putln("structBytes = item.Bytes()")
+	c.Putln("copy(buf[b:], len(structBytes))")
+	c.Putln("b += len(structBytes)")
+	c.Putln("}")
+	c.Putln("return b")
+	c.Putln("}")
+}
+
+func (s *Struct) WriteListSize(c *Context) {
+	c.Putln("// Struct list size %s", s.SrcName())
+	c.Putln("func %sListSize(list []%s) int {", s.SrcName(), s.SrcName())
+	c.Putln("size := 0")
+	c.Putln("for _, item := range list {")
+	c.Putln("size += %s", s.Size().Reduce("item.", ""))
+	c.Putln("}")
+	c.Putln("return pad(size)")
+	c.Putln("}")
+	c.Putln("")
+}
diff --git a/nexgb/xgbgen/go_union.go b/nexgb/xgbgen/go_union.go
new file mode 100644
index 0000000..5721c49
--- /dev/null
+++ b/nexgb/xgbgen/go_union.go
@@ -0,0 +1,15 @@
+package main
+
+// Union types
+func (u *Union) Define(c *Context) {
+	c.Putln("// Union definition %s", u.SrcName())
+}
+
+func (u *Union) Read(c *Context, prefix string) {
+	c.Putln("// Union read %s", u.SrcName())
+}
+
+func (u *Union) Write(c *Context, prefix string) {
+	c.Putln("// Union write %s", u.SrcName())
+}
+