symbol.java

来自「纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统」· Java 代码 · 共 128 行

//
// Symbol.java
//

package org.jnode.linker;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;


public class Symbol
{
	/**
	* symbol table - page 4-25, figure 4-15
	* typedef struct
	* {
	*     Elf32_Word    st_name;
	*     Elf32_Addr    st_value;
	*     Elf32_Word    st_size;
	*     unsigned char st_info;
	*     unsigned char st_other;
	*     Elf32_Half    st_shndx;
	* } Elf32_Sym;
	**/
	public static final int SHN_ABS		= 0xFFFFFFF1;
	public static final int SHN_COMMON	= 0xFFFFFFF2;
	public static final int SHN_UNDEF	= 0;

	// Symbol binding
	public static final int STB_LOCAL		= 0;
	public static final int STB_GLOBAL	= 1;
	public static final int STB_WEAK		= 2;
	public static final int STB_LOPROC	= 13;
	public static final int STB_HIPROC	= 15;
	
	// Symbol type
	public static final int STT_NOTYPE	= 0;
	public static final int STT_OBJECT	= 1;
	public static final int STT_FUNC		= 2;
	public static final int STT_SECTION	= 3;
	public static final int STT_FILE		= 4;
	public static final int STT_LOPROC	= 13;
	public static final int STT_HIPROC	= 15;
	
	private int st_name;
	private int st_value;
	private int st_size;
	private int st_info;
	private int st_other;
	private int st_shndx;
	private Elf elf;
	
	public Symbol(Elf elf, InputStream in)
	throws IOException
	{
		this.elf = elf;
		st_name = LoadUtil.little32(in);
		st_value = LoadUtil.little32(in);
		st_size = LoadUtil.little32(in);
		st_info = LoadUtil.little8(in);
		st_other = LoadUtil.little8(in);
		st_shndx = LoadUtil.little16(in);
	}
	
	public Symbol(Elf elf, String name, int value, Section section)
	{
		this.elf = elf;
		if (name != null) {
			this.st_name = elf.addString(name);
		} else {
			this.st_name = 0;
		}
		this.st_value = value;
		if (section != null) {
			this.st_shndx = elf.getSectionIndex(section);
		} else {
			this.st_shndx = SHN_UNDEF;
		}
		this.st_info = (STB_GLOBAL<<4)|(STT_FUNC&0xF);
	}

	public int store(OutputStream out)
	throws IOException
	{
		int cnt = 0;
		cnt += StoreUtil.little32(out, st_name);
		cnt += StoreUtil.little32(out, st_value);
		cnt += StoreUtil.little32(out, st_size);
		cnt += StoreUtil.little8(out, st_info);
		cnt += StoreUtil.little8(out, st_other);
		cnt += StoreUtil.little16(out, st_shndx);
		return cnt;
	}

	public String toString()			{ return getName() + ", " + getValue(); }
	public String getName()				{ return elf.getString(st_name); }
	public int getValue()					{ return st_value; }
	public void setValue(int v)		{ st_value = v; }
	public int getSize()					{ return st_size; }
	public void setSize(int v)		{ st_size = v; }
	public int getBind()					{ return (st_info>>4); }
	public void setBind(int v)		{ setInfo(v, getType()); }
	public int getType()					{ return (st_info&0xF); }
	public void setType(int v)		{ setInfo(getBind(), v); }
	public void setInfo(int bind, int type)		{ st_info = (bind<<4) | (type&0xf); }
	public int getOther()					{ return st_other; }
	public void setOther(int v)		{ st_other = v; }
	public int getSectionIndex()	{ return st_shndx; }
	public Section getSection()		{ return elf.getSection(st_shndx); }

	public boolean isAbs()				{ return (st_shndx == SHN_ABS); }
	public void setAbs()					{ st_shndx = SHN_ABS; }
	public boolean isUndef()			{ return (st_shndx == SHN_UNDEF); }
	public void setUndef()				{ st_shndx = SHN_UNDEF; }

	public void print()
	{
		System.out.println( "  ----- Symbol -----" );
		System.out.println( "  st_name       : " + getName());
		System.out.println( "  st_value      : " + Integer.toString( st_value, 16));
		System.out.println( "  st_size       : " + Integer.toString( st_size,  16));
		System.out.println( "  st_info       : " + Integer.toString( st_info,  16));
		System.out.println( "  st_other      : " + Integer.toString( st_other, 16));
		System.out.println( "  st_section    : " + st_shndx /* + getSection().getName()*/);
	}
}