slightly optimize generated code

Author: cce

network/vpack/gen.go

@@ -134,10 +134,14 @@ const parseFuncFooter = `
 // parseFuncTemplate decodes a struct encoded as a map.
 // It calls `makeNumericConst` for special integer values in a top-level FuncMap.
 const parseFuncTemplate = `
-	cnt, err := p.expectWriteMapMarker({{.MaxFieldCount}}, c)
+	cnt, err := p.readFixMap()
 	if err != nil {
-		return fmt.Errorf("map for {{.TypeName}}: %w", err)
+		return fmt.Errorf("reading map for {{.TypeName}}: %w", err)
 	}
+	if cnt < 1 || cnt > {{.MaxFieldCount}} {
+		return fmt.Errorf("expected fixmap size for {{.TypeName}} 1 <= cnt <= {{.MaxFieldCount}}, got %d", cnt)
+	}
+	c.writeStatic(StaticIdxMapMarker0+cnt)
 
 	for range cnt {
 		key, err := p.readString()
@@ -153,6 +157,7 @@ const parseFuncTemplate = `
 			c.writeStatic({{$fd.FieldNameConst}})
 			{{renderParseFunction $fd.SubStructName}}
   {{- else if $fd.IsUint64Alias}}
+            {{ if not $fd.VpackSpecial }}c.writeStatic({{$fd.FieldNameConst}}){{end}}
 			valBytes, err := p.readUintBytes()
 			if err != nil {
 				return fmt.Errorf("reading {{$fd.CodecName}}: %w", err)
@@ -170,9 +175,10 @@ const parseFuncTemplate = `
 				}
 			}
 	{{end}}
-			c.writeStatic({{$fd.FieldNameConst}})
+			{{ if $fd.VpackSpecial }}c.writeStatic({{$fd.FieldNameConst}}){{ end }}
 			c.writeDynamicVaruint(valBytes)
   {{- else if gt $fd.ArrayLen 0}}
+            {{ if and (not $fd.VpackSpecial) (not $fd.IsZeroCheck) }}c.writeStatic({{$fd.FieldNameConst}}){{end}}
 			val, err := p.readBin{{$fd.ArrayLen}}()
 			if err != nil {
 				return fmt.Errorf("reading {{$fd.CodecName}}: %w", err)
@@ -185,10 +191,10 @@ const parseFuncTemplate = `
 				c.writeLiteralBin{{$fd.ArrayLen}}(val)
 			}
 	{{- else if $fd.IsLiteral}}
-			c.writeStatic({{$fd.FieldNameConst}})
+			{{ if $fd.VpackSpecial }}c.writeStatic({{$fd.FieldNameConst}}){{ end }}
 			c.writeLiteralBin{{$fd.ArrayLen}}(val)
 	{{- else}}
-			c.writeStatic({{$fd.FieldNameConst}})
+			{{ if $fd.VpackSpecial }}c.writeStatic({{$fd.FieldNameConst}}){{ end }}
 			c.writeDynamicBin{{$fd.ArrayLen}}(val)
 	{{- end}}
   {{- else}}
@@ -232,7 +238,7 @@ func (g *codeGenerator) generate(root reflect.Type) error {
 	// Also define map-marker constants for 1..6
 	// We don't need more than this, and an error will be thrown if a
 	// field grows beyond 6 items.
-	for i := 1; i <= 6; i++ {
+	for i := 0; i <= 6; i++ {
 		g.getOrCreateMapMarkerIndex(i)
 	}
 

network/vpack/msgp.go

@@ -184,30 +184,3 @@ func (p *parser) readUintBytes() ([]byte, error) {
 	p.pos += dataSize
 	return p.data[startPos : startPos+dataSize+1], nil
 }
-
-func (p *parser) expectWriteMapMarker(maxSz int, c compressWriter) (int, error) {
-	cnt, err := p.readFixMap()
-	if err != nil {
-		return 0, err
-	}
-	if cnt < 1 || cnt > maxSz {
-		return 0, fmt.Errorf("expected fixmap size %d <= cnt <= %d, got %d", 1, maxSz, cnt)
-	}
-	switch cnt {
-	case 1:
-		c.writeStatic(StaticIdxMapMarker1)
-	case 2:
-		c.writeStatic(StaticIdxMapMarker2)
-	case 3:
-		c.writeStatic(StaticIdxMapMarker3)
-	case 4:
-		c.writeStatic(StaticIdxMapMarker4)
-	case 5:
-		c.writeStatic(StaticIdxMapMarker5)
-	case 6:
-		c.writeStatic(StaticIdxMapMarker6)
-	default:
-		return 0, fmt.Errorf("unexpected fixmap size: %d", cnt)
-	}
-	return cnt, nil
-}