snuvi-script-recoded/src/me/hammerle/snuviscript/tokenizer/StreamCharReader.java

package me.hammerle.snuviscript.tokenizer;

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

public class StreamCharReader {
    private final InputStream in;
    private int buffer = -1;

    public StreamCharReader(InputStream in) {
        this.in = in;
    }

    public int peekChar() {
        if(buffer == -1) {
            buffer = readChar();
            return buffer;
        }
        return buffer;
    }

    public int readChar() {
        if(buffer != -1) {
            int r = buffer;
            buffer = -1;
            return r;
        }
        try {
            if(in.available() <= 0) {
                return -1;
            }
            int data = in.read();
            if((data & 0x80) != 0) // special char
            {
                if((data & 0x40) != 0) // this should always be true
                {
                    if((data & 0x20) != 0) // 3 byte unicode
                    {
                        int a = in.read();
                        int b = in.read();
                        data = ((data & 0xF) << 12) | ((a & 0x3F) << 6) | (b & 0x3F);
                    } else // 2 byte unicode
                    {
                        data = ((data & 0x1F) << 6) | (in.read() & 0x3F);
                    }
                } else {
                    // should not happen as unicode starts with 11
                }
            }
            return data;
        } catch(IOException ex) {
            return -1;
        }
    }
}