用go编写java虚拟机

package main import ( "./constan" "encoding/binary" "encoding/json" "fmt" ) type Class struct { Magic uint32 `json:"magic"` // 魔数 MinorVersionMin uint16 `json:"minor_version_min"` // 副版本号 MinorVersion uint16 `json:"minor_version"` //主版本号 ConstantPoolCount uint16 `json:"constant_pool_count"` //常量池计数器 ConstantPoolInfo []ConstantPoolInfo `json:"constant_pool_info"` // 常量池 AccessFlags uint16 `json:"access_flags"` //访问标志 ThisClass uint16 `json:"this_class"` //类索引， SuperClass uint16 `json:"super_class"` //父类索引， InterfaceCount uint16 `json:"interface_count"` //接口计数器 interfaces []interface{} `json:"interfaces"` //接口表 FieldsCount uint16 `json:"fields_count"` //字段计数器 FieldInfo []interface{} `json:"field_info"` //字段表 MethodCount uint16 `json:"method_count"` //方法计数器 MethodInfo []*Method `json:"method_info"` //方法表 AttributesCount uint16 `json:"attributes_count"` //属性计数器 AttributeInfo []Attribute `json:"attribute_info"` } func (c Class) PrintClassInfo() { buf, err := json.MarshalIndent(c, "", " ") //格式化编码 if err != nil { fmt.Println("err = ", err) } fmt.Println("buf = ", string(buf)) } type ClassBytes struct { Bytes []byte Class *Class } func (C *ClassBytes) AnalysisClass() { class := C.Class //解析魔数 class.Magic = binary.BigEndian.Uint32(C.Bytes[:4]) //小版本号 class.MinorVersionMin = binary.BigEndian.Uint16(C.Bytes[4:6]) //大版本号 class.MinorVersionMin = binary.BigEndian.Uint16(C.Bytes[6:8]) //读取常量池 class.ConstantPoolCount = binary.BigEndian.Uint16(C.Bytes[8:10]) //去除已经读过的字节 C.Bytes = C.Bytes[10:] if class.ConstantPoolCount != 0 { //调用常量池读取方法 pool := C.AnalysisClassReadeConstantPool(int(class.ConstantPoolCount)) class.ConstantPoolInfo = pool } //访问控制 class.AccessFlags = binary.BigEndian.Uint16(C.Bytes[:2]) //类索引 class.ThisClass = binary.BigEndian.Uint16(C.Bytes[2:4]) //父类 class.SuperClass = binary.BigEndian.Uint16(C.Bytes[4:6]) //接口计数器 class.InterfaceCount = binary.BigEndian.Uint16(C.Bytes[6:8]) //先去除读过的字节 C.Bytes = C.Bytes[8:] //判断是否用接口 if class.InterfaceCount != 0 { //解析接口 } //字段计数器 class.FieldsCount = binary.BigEndian.Uint16(C.Bytes[:2]) //先去除读过的字节 C.Bytes = C.Bytes[2:] //判断是否有字段 if class.InterfaceCount != 0 { //解析字段 } //方法计数器 class.MethodCount = binary.BigEndian.Uint16(C.Bytes[:2]) //先去除读过的字节 C.Bytes = C.Bytes[2:] //判断是否有方法 if class.MethodCount != 0 { //解析方法 method := C.AnalysisClassReadeMethod(int(class.MethodCount)) class.MethodInfo = method } //属性计数器 class.AttributesCount = binary.BigEndian.Uint16(C.Bytes[:2]) //先去除读过的字节 C.Bytes = C.Bytes[2:] //判断是否有属性 if class.AttributesCount != 0 { //属性解析 attributes := C.AnalysisClassReadeAttributes(int(class.AttributesCount), class) class.AttributeInfo = attributes } } func (C *ClassBytes) AnalysisClassReadeAttributes(count int, class *Class) []Attribute { var attribute []Attribute = make([]Attribute, count) for i := 0; i < count; i++ { //2字节名称 nameIndex := binary.BigEndian.Uint16(C.Bytes[:2]) info := class.ConstantPoolInfo[nameIndex] //强转，接口转成结构体 utf8Info := info.(*ConstantUtf8Info) //取出string s := string(utf8Info.Bytes) length := binary.BigEndian.Uint32(C.Bytes[2:6]) //取属性信息 bytes := C.Bytes[6 : 6+length] C.Bytes = C.Bytes[6+length:] switch s { case constan.CODE: //j解析code codeAttribute := CodeAttribute{} codeAttribute.AttributeNameIndex = nameIndex codeAttribute.AttributeLength = length //栈深 codeAttribute.MaxStack = binary.BigEndian.Uint16(bytes[:2]) //空间 codeAttribute.MaxLocals = binary.BigEndian.Uint16(bytes[2:4]) //指令长度 codeAttribute.CodeLengthInfo = binary.BigEndian.Uint32(bytes[4:8]) //指令 codeAttribute.CodeInfo = bytes[8 : 8+codeAttribute.CodeLengthInfo] //异常 bytes = bytes[8+codeAttribute.CodeLengthInfo:] codeAttribute.ExceptionTableLength = binary.BigEndian.Uint16(bytes[:2]) //先去除读过的字节 bytes = bytes[2:] //判断是否有异常 if codeAttribute.ExceptionTableLength != 0 { //异常 } //其它属性 codeAttribute.AttributesCountInfo = binary.BigEndian.Uint16(bytes[:2]) //先去除读过的字节 bytes = bytes[2:] //判断是否有属性 if codeAttribute.AttributeLength != 0 { //其它属性 //递归 //这里注意递归不要改变原来的class的值 var c ClassBytes c.Bytes = bytes attributes := c.AnalysisClassReadeAttributes(int(codeAttribute.AttributesCountInfo), class) codeAttribute.AttributeInfo = attributes } attribute[i] = codeAttribute case constan.LINENUMBERTABLE: //LINENUMBERTABLE lineNumberTableAttribute := LineNumberTableAttribute{} lineNumberTableAttribute.AttributeNameIndex = nameIndex lineNumberTableAttribute.AttributeLength = length lineNumberTableAttribute.Infos = bytes attribute[i] = lineNumberTableAttribute case constan.LOCALVARIABLETABLE: //LOCALVARIABLETABLE localVariableTable := LocalVariableTable{} localVariableTable.AttributeNameIndex = nameIndex localVariableTable.AttributeLength = length localVariableTable.Infos = bytes attribute[i] = localVariableTable case constan.SOURCEFILE: //SOURCEFILE sourceFile := SourceFile{} sourceFile.AttributeNameIndex = nameIndex sourceFile.AttributeLength = length sourceFile.Infos = bytes attribute[i] = sourceFile } } return attribute } func (C *ClassBytes) AnalysisClassReadeMethod(count int) []*Method { var method []*Method = make([]*Method, count) for i := 0; i < count; i++ { m := Method{} ////访问标识 m.AccessFlags = binary.BigEndian.Uint16(C.Bytes[:2]) m.NameIndex = binary.BigEndian.Uint16(C.Bytes[2:4]) m.DescriptorIndex = binary.BigEndian.Uint16(C.Bytes[4:6]) m.AttributesCount = binary.BigEndian.Uint16(C.Bytes[6:8]) //先去除读过的字节 C.Bytes = C.Bytes[8:] //判断是否有属性 if m.AttributesCount != 0 { //属性解析 C.AnalysisClassReadeAttributes(int(m.AttributesCount), C.Class) } method[i] = &m } return method } func (C *ClassBytes) AnalysisClassReadeConstantPool(count int) []ConstantPoolInfo { var constantPoolInfo []ConstantPoolInfo = make([]ConstantPoolInfo, count) //这里较为复杂,先循环 for i := 1; i < count; i++ { //读取tag tag := C.Bytes[0] switch tag { case constan.CONSTANT_Class: //类信息ConstantClassInfo info := &ConstantClassInfo{} info.Tag = tag info.NameIndex = binary.BigEndian.Uint16(C.Bytes[1:3]) C.Bytes = C.Bytes[3:] constantPoolInfo[i] = info case constan.CONSTANT_Fieldref: //字段 info := &ConstantFieldrefInfo{} info.Tag = tag info.ClassIndex = binary.BigEndian.Uint16(C.Bytes[1:3]) info.nameAndTypeIndex = binary.BigEndian.Uint16(C.Bytes[3:5]) C.Bytes = C.Bytes[5:] constantPoolInfo[i] = info case constan.CONSTANT_Methodref: //方法ConstantMethodrefInfo info := &ConstantMethodrefInfo{} info.Tag = tag info.ClassIndex = binary.BigEndian.Uint16(C.Bytes[1:3]) info.nameAndTypeIndex = binary.BigEndian.Uint16(C.Bytes[3:5]) C.Bytes = C.Bytes[5:] constantPoolInfo[i] = info case constan.CONSTANT_InterfaceMethodref: case constan.CONSTANT_String: //方法ConstantStringInfo info :