.

t/neo/protogen.go

@@ -126,16 +126,14 @@ func main() {
 	// prologue
 	f := fv[0]	// proto.go comes first
 	buf := Buffer{}
-	// XXX vvv -> emit
-	buf.WriteString(`// DO NOT EDIT - AUTOGENERATED (by protogen.go)
+	buf.emit(`// DO NOT EDIT - AUTOGENERATED (by protogen.go)
 
 package neo
 import (
 	"encoding/binary"
 	"reflect"
 	"sort"
-)
-`)
+)`)
 
 	pktTypeRegistry := map[int]string{}	// pktCode -> typename
 
@@ -474,6 +472,7 @@ type decoder struct {
 
 	n     int	// current read position in data.
 	nread int	// numeric part of total nread return
+	nreadStk []int	// stack to push/pop nread on loops
 
 	// overflow check state and size that will be checked for overflow at
 	// current overflow check point
@@ -529,7 +528,6 @@ func (d *decoder) resetPos() {
 	}
 }
 
-// XXX place?
 // mark current place for delayed insertion of overflow check code
 //
 // delayed: because we go forward in decode path scanning ahead as far as we
@@ -543,8 +541,8 @@ func (d *decoder) resetPos() {
 //
 // it is inserted
 // - before reading a variable sized item
-// - in the beginning of a loop inside
-// - right after loop exit
+// - in the beginning of a loop inside	(via overflowCheckLoopEntry)
+// - right after loop exit		(via overflowCheckLoopExit)
 func (d *decoder) overflowCheck() {
 	// nop if we know overflow was already checked
 	if d.overflow.checked {
@@ -561,7 +559,7 @@ func (d *decoder) overflowCheck() {
 		// otherwise accumulate into var(nread) at runtime.
 		// we do not break runtime accumulation into numeric & symbolic
 		// parts, because just above whole expression num + symbolic
-		// was just given to compiler so compiler shoud have it just computed.
+		// was just given to compiler so compiler should have it just computed.
 		// XXX recheck ^^^ actually good with the compiler
 		if d.overflow.checkSize.IsNumeric() {
 			d.nread += d.overflow.checkSize.num
@@ -576,6 +574,39 @@ func (d *decoder) overflowCheck() {
 	d.buf.Reset()
 }
 
+// overflowCheck variant that should be called at the beginning of a loop inside
+func (d *decoder) overflowCheckLoopEntry() {
+	if d.overflow.checked {
+		return
+	}
+
+	d.overflowCheck()
+
+	// upon entering a loop organize new nread, because what was statically
+	// read inside loop should be multiplied by loop len in parent context.
+	d.nreadStk = append(d.nreadStk, d.nread)
+	d.nread = 0
+}
+
+// overflowCheck variant that should be called right after loop exit
+func (d *decoder) overflowCheckLoopExit(loopLenExpr string) {
+	if d.overflow.checked {
+		return
+	}
+
+	d.overflowCheck()
+
+	// merge-in numeric nread updates from loop
+	if d.nread != 0 {
+		d.emit("%v += %v * %v", d.var_("nread"), loopLenExpr, d.nread)
+	}
+	l := len(d.nreadStk)
+	d.nread = d.nreadStk[l-1]
+	d.nreadStk = d.nreadStk[:l-1]
+}
+
+
+
 func (d *decoder) generatedCode() string {
 	// flush for last overflow check point
 	d.overflowCheck()
@@ -590,7 +621,6 @@ func (d *decoder) generatedCode() string {
 	code.Write(d.bufDone.Bytes())
 
 	// epilogue
-	//retexpr := fmt.Sprintf("%v", d.n)
 	retexpr := fmt.Sprintf("%v", d.nread)
 	if d.varUsed["nread"] {
 		retexpr += fmt.Sprintf(" + int(%v)", d.var_("nread"))
@@ -772,28 +802,13 @@ func (d *decoder) genSlice(assignto string, typ *types.Slice, obj types.Object)
 	d.emit("%v= make(%v, l)", assignto, typeName(typ))
 	d.emit("for i := 0; uint32(i) < l; i++ {")
 	d.emit("a := &%s[i]", assignto)
-
-	d.overflowCheck()	// -> overflowCheckLoopEntry ?
-	var nreadCur int
-	if !d.overflow.checked {	// TODO merge-in into overflow checker
-		nreadCur = d.nread
-		d.nread = 0
-	}
+	d.overflowCheckLoopEntry()
 
 	codegenType("(*a)", typ.Elem(), obj, d)
 
 	d.resetPos()
-
 	d.emit("}")
-	d.overflowCheck()	// -> overflowCheckPointLoopExit("l") ?
-
-	// merge-in numeric nread updates from loop
-	if !d.overflow.checked {
-		if d.nread != 0 {
-			d.emit("%v += l * %v", d.var_("nread"), d.nread)
-		}
-		d.nread = nreadCur
-	}
+	d.overflowCheckLoopExit("l")
 
 	d.emit("}")
 }
@@ -871,13 +886,7 @@ func (d *decoder) genMap(assignto string, typ *types.Map, obj types.Object) {
 	d.emit("%v= make(%v, l)", assignto, typeName(typ))
 	d.emit("m := %v", assignto)
 	d.emit("for i := 0; uint32(i) < l; i++ {")
-
-	d.overflowCheck()	// -> overflowCheckPointLoopEntry ?
-	var nreadCur int
-	if !d.overflow.checked {	// TODO merge-in into overflow checker
-		nreadCur = d.nread
-		d.nread = 0
-	}
+	d.overflowCheckLoopEntry()
 
 	codegenType("key:", typ.Key(), obj, d)
 
@@ -894,17 +903,8 @@ func (d *decoder) genMap(assignto string, typ *types.Map, obj types.Object) {
 	}
 
 	d.resetPos()
-
 	d.emit("}")
-	d.overflowCheck()	// -> overflowCheckPointLoopExit("l") ?
-
-	// merge-in numeric nread updates from loop
-	if !d.overflow.checked {
-		if d.nread != 0 {
-			d.emit("%v += l * %v", d.var_("nread"), d.nread)
-		}
-		d.nread = nreadCur
-	}
+	d.overflowCheckLoopExit("l")
 
 	d.emit("}")
 }
@@ -912,7 +912,7 @@ func (d *decoder) genMap(assignto string, typ *types.Map, obj types.Object) {
 // top-level driver for emitting size/encode/decode code for a type
 //
 // obj is object that uses this type in source program (so in case of an error
-// we can point to source location for where it happenned)
+// we can point to source location for where it happened)
 func codegenType(path string, typ types.Type, obj types.Object, codegen CodeGenerator) {
 	switch u := typ.Underlying().(type) {
 	case *types.Basic: