Merge pull request #11 from kekeon/master

parser constant pool

jvm.com/classfile/attribute-info.go

@@ -0,0 +1,5 @@
+package classfile
+
+type AttributeInfo interface {
+	readInfo(reader *ClassReader)
+}

jvm.com/classfile/constant-info.go

@@ -0,0 +1,18 @@
+package classfile
+
+const (
+	CONSTANT_Class              = 7
+	CONSTANT_Fieldref           = 9
+	CONSTANT_Methodref          = 10
+	CONSTANT_InterfaceMethodref = 11
+	CONSTANT_String             = 8
+	CONSTANT_Integer            = 3
+	CONSTANT_Float              = 4
+	CONSTANT_Long               = 5
+	CONSTANT_Double             = 6
+	CONSTANT_NameAndType        = 12
+	CONSTANT_Utf8               = 1
+	CONSTANT_MethodHandle       = 15
+	CONSTANT_MethodType         = 16
+	CONSTANT_InvokeDynamic      = 18
+)

jvm.com/classfile/constant-pool.go

@@ -0,0 +1,94 @@
+package classfile
+
+type ConstantInfo interface {
+	readInfo(read *ClassReader)
+}
+
+type ConstantPool []ConstantInfo
+
+func readConstantPool(reader *ClassReader) ConstantPool {
+	cpCount := int(reader.readUint16())
+
+	cp := make([]ConstantInfo, cpCount)
+
+	for i := 1; i < cpCount; i++ {
+		cp[i] = readConstantInfo(reader, cp)
+
+		switch cp[i].(type) {
+		case *ConstantLongInfo, *ConstantDoubleInfo:
+
+			i++
+		}
+	}
+
+	return cp
+}
+
+func (self ConstantPool) getConstantInfo(index uint16) ConstantInfo {
+	if cpInfo := self[index]; cpinfo != nil {
+		return cpInfo
+	}
+
+	panic("Invalid constant pool index")
+}
+
+func (self *ConstantPool) getNameAndType(index uint16) (string, string) {
+	ntInfo := self.getConstantInfo(index).(*ConstantNameAndTypeInfo)
+	name := self.getUtf8(ntInfo.nameIndex)
+	_type := self.getUtf8(ngInfo.descriptorIndex)
+
+	return name, _type
+}
+
+func (self *ConstantPool) getClassName(index uint16) string {
+	return self.getUtf8(classInfo.nameIndex)
+}
+
+func (self *ConstantPool) getUtf8(index uint16) string {
+	utf8Info := self.getContantInfo(index).(*ConstantUtf8Info)
+
+	return utf8Info.str
+}
+
+func readConstantInfo(reader *ClassReader, cp ConstantPool) ConstantInfo {
+	tag := reader.readUint8()
+	c := newConstantInfo(tag, cp)
+	reader.readInfo(reader)
+
+	return c
+}
+
+func newConstantInfo(tag uint8, cp ConstantPool) ConstantInfo {
+	switch tag {
+	case CONSTANT_Integer:
+		return &ConstantIntegerInfo{}
+	case CONSTANT_FLOAD:
+		return &ConstantFloatInfo{}
+	case CONSTANT_lONG:
+		return &ConstantLongInfo{}
+	case CONSTANT_DOUBLE:
+		return &ConstantDouble{}
+	case CONSTANT_Utf8:
+		return &ConstantUft8Info{}
+	case CONSTANT_String:
+		return &ConstantStringInfo{cp: cp}
+	case CONSTANT_Class:
+		return &ConstantClassInfo{cp: cp}
+	case CONSTANT_Fieldref:
+		return &ConstantFieldrefInfo{ConstantMemberrefInfo{cp: cp}}
+	case CONSTANT_Methodref:
+		return &ConstantMethodrefInfo{ConstantMemberrefInfo{cp: cp}}
+	case CONSTANT_InterfaceMethodref:
+		return &ConstantInterfaceMethodrefInfo{ConstantMemberrefInfo{cp: cp}}
+	case CONSTANT_NameAndType:
+		return &ConstantNameAndTypeInfo{}
+	case CONSTANT_MethodType:
+		return &ConstantMethodTypeInfo{}
+	case CONSTANT_MethodHandle:
+		return &ConstantMethodHandleInfo{}
+	case CONSTANT_InvokeDynamic:
+		return &ConstantInvokeDynamicInfo{}
+	default:
+		panic("java.lang.ClassFormatError: constant pool tag!")
+	}
+}

jvm.com/classfile/cp-numeric.go

@@ -0,0 +1,40 @@
+package classfile
+
+import "math"
+
+type ConstantIntegerInfo struct {
+	val int32
+}
+
+type ConstantFloatInfo struct {
+	val float32
+}
+
+type ConstantLongInfo struct {
+	val int64
+}
+
+type ConstantDoubleInfo struct {
+	val float64
+}
+
+func (self *ConstantIntegerInfo) readInfo(reader *ClassReader) {
+	bytes := reader.readUint32()
+	self.val = int32(bytes)
+}
+
+func (self *ConstantFloatInfo) readInfo(reader *ClassReader) {
+	bytes := reader.readUint32()
+	self.val = math.Float32frombits(bytes)
+}
+
+func (self *ConstantLongInfo) readInfo(reader *ClassReader) {
+	bytes := reader.readUint64()
+
+	self.val = int64(bytes)
+}
+
+func (self *ConstantDoubleInfo) readInfo(reader *ClassReader) {
+	bytes := reader.readUint64()
+	self.val = math.Float64frombits(bytes)
+}

jvm.com/classfile/member-info.go

@@ -0,0 +1,40 @@
+package classfile
+
+type MemberInfo struct {
+	cp              ConstantPool
+	accessFlags     uint16
+	nameIndex       uint16
+	descriptorIndex uint16
+	attributes      []AttributeInfo
+}
+
+func readMemberInfo(reader *ClassReader, cp ConstantPool) []*MemberInfo {
+	memberCount := reader.readUint16()
+	members := make([]*MemberInfo, memberCount)
+
+	for i := range members {
+		members[i] = readMember(reader, cp)
+	}
+
+	return members
+}
+
+func readMember(reader *ClassReader, cp ConstantPool) *MemberInfo {
+	return &MemberInfo{
+		cp:          cp,
+		accessFlags: reader.readUint16(),
+		nameIndex:   reader.readUint16(),
+		attributes:  readAttributes(reader, cp),
+	}
+}
+
+func (self *MemberInfo) AccessFlags() uint16 {
+}
+
+func (self *MemberInfo) Name() string {
+	return self.cp.getUtf8(self.descriptorIndex)
+}
+
+func (self *MemberInfo) Descriptor() string {
+	return self.cp.getUtf8(self.descriptorIndex)
+}