Class CodeExtract

UnLuac/src/unluac/decompile/CodeExtract.java:5–121

import unluac.Version;

public class CodeExtract {

public static class Field {
    
    public Field(int size, int shift) {
      this(size, shift, 0);
    }
    
    public Field(int size, int shift, int offset) {
      this.size = size;
      this.shift = shift;
      this.mask = size_to_mask(size);
      this.offset = offset;
    }
    
    public int extract(int codepoint) {
      return ((codepoint >>> shift) & mask) - offset;
    }
    
    public boolean check(int x) {
      return ((x + offset) & ~mask) == 0;
    }
    
    public int encode(int x) {
      return (x + offset) << shift;
    }
    
    public int clear(int codepoint) {
      return codepoint & ~(mask << shift);
    }
    
    public int max() {
      return mask - offset;
    }
    
    public final int size;
    private final int shift;
    private final int mask;
    private final int offset;
    
  }
  
  public CodeExtract(Version version, int sizeOp, int sizeA, int sizeB, int sizeC) {
    switch(version.instructionformat.get()) {
      case LUA50:
        op = new Field(sizeOp, 0);
        A = new Field(sizeA, sizeB + sizeC + sizeOp);
        B = new Field(sizeB, sizeB + sizeOp);
        C = new Field(sizeC, sizeOp);
        k = null;
        Ax = null;
        sJ = null;
        Bx = new Field(sizeB + sizeC, sizeOp);
        sBx = new Field(sizeB + sizeC, sizeOp, size_to_mask(sizeB + sizeC) / 2);
        x = new Field(32, 0);
        break;
      case LUA51:
        op = new Field(6, 0);