jclass 0.1.7

a simple lib for java class file parse or edit
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

use crate::attribute_info::OriginAttribute;
use crate::support::data_reader::{DataReader, DataWriter, ReadToType, WriteFromType};
use crate::common::error::Result;
use std::io::{Read, Write};

#[derive(Clone, Debug)]
pub struct FieldInfo {
    pub access_flags: u16,
    pub name: u16,
    pub descriptor: u16,
    pub attributes: Vec<OriginAttribute>
}

impl FieldInfo {
    pub fn new_from_reader<T: Read>(reader: &mut DataReader<T>) -> Result<FieldInfo> {
        let access_flags: u16 = reader.read_to("字段访问标识")?;
        let name: u16 = reader.read_to("字段名")?;
        let descriptor: u16 = reader.read_to("字段描述")?;
        let attribute_size: u16 = reader.read_to("字段属性数量")?;
        let mut attributes = Vec::with_capacity(attribute_size as usize);
        for _ in 0..attribute_size {
            attributes.push(OriginAttribute::new_from_reader(reader)?)
        }
        Ok(FieldInfo {
            access_flags,
            name,
            descriptor,
            attributes
        })
    }

    pub fn write_to<T: Write>(&self, writer: &mut DataWriter<T>) -> Result<()> {
        writer.write_from("字段访问标识", self.access_flags)?;
        writer.write_from("字段名", self.name)?;
        writer.write_from("字段描述", self.descriptor)?;
        writer.write_from("字段属性数量", self.attributes.len() as u16)?;
        for attribute in &self.attributes {
            attribute.write_to(writer)?;
        }
        Ok(())
    }

    //noinspection DuplicatedCode
    pub fn byte_size(&self) -> usize {
        let mut attrs_size = 0;
        for attr in &self.attributes {
            attrs_size += attr.byte_size();
        }
        attrs_size + size_of::<[u16;3]>() + size_of::<u16>() //字段属性数量
    }
}