package minejava.reg.io;

import minejava.reg.lang.IndexOutOfBoundsException;
import minejava.reg.lang.Math;
import minejava.reg.lang.NullPointerException;
import minejava.reg.lang.System;

public class ByteArrayInputStream extends InputStream{

    protected byte buf[];

    protected int pos;

    protected int mark = 0;

    protected int count;

    public ByteArrayInputStream(byte buf[]){
        this.buf = buf;
        this.pos = 0;
        this.count = buf.length;
    }

    public ByteArrayInputStream(byte buf[], int offset, int length){
        this.buf = buf;
        this.pos = offset;
        this.count = Math.min(offset + length, buf.length);
        this.mark = offset;
    }

    public synchronized int read(){
        return (pos < count) ? (buf[pos++] & 0xff) : -1;
    }

    public synchronized int read(byte b[], int off, int len){
        if (b == null){
            throw new NullPointerException();
        }else if (off < 0 || len < 0 || len > b.length - off){
            throw new IndexOutOfBoundsException();
        }

        if (pos >= count){
            return -1;
        }

        int avail = count - pos;
        if (len > avail){
            len = avail;
        }
        if (len <= 0){
            return 0;
        }
        System.arraycopy(buf, pos, b, off, len);
        pos += len;
        return len;
    }

    public synchronized long skip(long n){
        long k = count - pos;
        if (n < k){
            k = n < 0 ? 0 : n;
        }

        pos += k;
        return k;
    }

    public synchronized int available(){
        return count - pos;
    }

    public boolean markSupported(){
        return true;
    }

    public void mark(int readAheadLimit){
        mark = pos;
    }

    public synchronized void reset(){
        pos = mark;
    }

    public void close() throws IOException{
    }

}