Enum VerificationType 

pub enum VerificationType {
    Top,
    Integer,
    Float,
    Double,
    Long,
    Null,
    UninitializedThis,
    Object {
        cpool_index: u16,
    },
    Uninitialized {
        offset: u16,
    },
}

Represents a verification type used in the Java Virtual Machine’s type checking system.

Verification types are used during bytecode verification to track the types of values on the operand stack and in local variables. They are primarily used in the StackMapTable attribute, which helps the JVM perform type checking during class loading.

Examples

use ristretto_classfile::attributes::VerificationType;

// Create primitive verification types
let top_type = VerificationType::Top;
let int_type = VerificationType::Integer;
let float_type = VerificationType::Float;
let double_type = VerificationType::Double;
let long_type = VerificationType::Long;
let null_type = VerificationType::Null;
let uninit_this = VerificationType::UninitializedThis;

// Create reference verification types
let object_type = VerificationType::Object { cpool_index: 15 };
let uninit_type = VerificationType::Uninitialized { offset: 42 };

Serializing and deserializing verification types:

use ristretto_classfile::attributes::VerificationType;
use ristretto_classfile::byte_reader::ByteReader;

// Serialize an Object verification type
let object_type = VerificationType::Object { cpool_index: 15 };
let mut bytes = Vec::new();
object_type.to_bytes(&mut bytes)?;
assert_eq!(bytes, vec![0x07, 0x00, 0x0F]); // Tag 7 + index 15 (big-endian)

// Deserialize back from bytes
let mut reader = ByteReader::new(&bytes);
let deserialized = VerificationType::from_bytes(&mut reader)?;
assert_eq!(deserialized, object_type);

References

• JVMS §4.7.4

Variants

Top

Integer

Float

Double

Long

Null

UninitializedThis

Object

Fields

cpool_index: u16

Uninitialized

Fields

offset: u16

Implementations

impl VerificationType

pub fn tag(&self) -> u8

Return the tag for the verification type.

See: https://docs.oracle.com/javase/specs/jvms/se25/html/jvms-4.html#jvms-VerificationTypeInfo

Examples

use ristretto_classfile::attributes::VerificationType;

let top_type = VerificationType::Top;
assert_eq!(top_type.tag(), 0);

let int_type = VerificationType::Integer;
assert_eq!(int_type.tag(), 1);

pub fn from_bytes(bytes: &mut ByteReader<'_>) -> Result<VerificationType>

Deserialize the verification type from bytes.

Errors

Returns an error if the tag is invalid.

Examples

use ristretto_classfile::attributes::VerificationType;
use ristretto_classfile::byte_reader::ByteReader;

let bytes = vec![0x07, 0x00, 0x0A]; // Object type with cpool_index 10
let mut reader = ByteReader::new(&bytes);
let verification_type = VerificationType::from_bytes(&mut reader)?;
assert_eq!(verification_type, VerificationType::Object { cpool_index: 10 });

pub fn to_bytes(&self, bytes: &mut Vec<u8>) -> Result<()>

Serialize the verification type to bytes.

Errors

Should not occur; reserved for future use.

Examples

use ristretto_classfile::attributes::VerificationType;

let object_type = VerificationType::Object { cpool_index: 10 };
let mut bytes = Vec::new();
object_type.to_bytes(&mut bytes)?;
assert_eq!(bytes, vec![0x07, 0x00, 0x0A]);

Trait Implementations

impl Clone for VerificationType

fn clone(&self) -> VerificationType

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VerificationType

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for VerificationType

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Implements the Display trait for VerificationType, providing a human-readable string representation of each verification type.

Examples

Using the Display trait to format verification types as strings:

use ristretto_classfile::attributes::VerificationType;

let output = VerificationType::Top.to_string();
assert_eq!(output, "top");

impl Eq for VerificationType

impl PartialEq for VerificationType

fn eq(&self, other: &VerificationType) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for VerificationType