import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.io.Writer;

/**
* $Log: HTMLEncoding.java,v $
 * Revision 1.1  2005/08/04 09:46:24  zhourj
 * 实现替换HTML中对UTF的地址为GBK
 *
 */
public class HTMLEncoding {
    public static void convertURI2GBK(Reader reader, Writer writer) throws IOException {
        StringBuffer firstLine = new StringBuffer();
        StringBuffer nextLine = new StringBuffer();
        char[] buf = new char[1024];
        
        int read = 0;
        while (firstLine.length() < 512) {
            read = reader.read(buf);
            if (read == -1) {
                break;
            }
            firstLine.append(buf, 0, read);
        }
        boolean isEncodingReplace = false;
        while (read != -1) {
            while (nextLine.length() < 512) {
                read = reader.read(buf);
                if (read == -1) {
                    break;
                }
                nextLine.append(buf, 0, read);
            }
            String currentStr = firstLine.toString() + nextLine.toString();
            if (!isEncodingReplace) {
                String contentStr = currentStr.replaceFirst("charset=UTF-8", "charset=utf-8");  //$NON-NLS-1$//$NON-NLS-2$
                if (!contentStr.equals(currentStr)) {
                    isEncodingReplace = true;
                    currentStr = contentStr;
                }
            }
            if (currentStr.indexOf('%') != -1) {
                int i = 0;
                int length = currentStr.length();
                StringBuffer buffer = new StringBuffer();
                while (i < length - 9) {
                    if (!(currentStr.charAt(i) == '%' && i + 6 < length
                            && currentStr.charAt(i + 3) == '%'
                            && currentStr.charAt(i + 6) == '%')) {
                        buffer.append(currentStr.charAt(i));
                    } else {
                        byte[] chars = new byte[3];
                        chars[0] = (byte) (getCharHex(currentStr.charAt(i + 1)) * 16);
                        chars[0] += getCharHex(currentStr.charAt(i + 2));
                        chars[1] = (byte) (getCharHex(currentStr.charAt(i + 4)) * 16);
                        chars[1] += getCharHex(currentStr.charAt(i + 5));
                        chars[2] = (byte) (getCharHex(currentStr.charAt(i + 7)) * 16);
                        chars[2] += getCharHex(currentStr.charAt(i + 8));
//                        byte[] bytes = new String(chars, "utf-8").getBytes("gbk");  //$NON-NLS-1$//$NON-NLS-2$
//                        buf.append('%');
//                        buf.append(byte2HexStr(bytes[0]));
//                        buf.append('%');
//                        buf.append(byte2HexStr(bytes[1]));
                        buffer.append(new String(chars, "utf-8").charAt(0)); //$NON-NLS-1$
                        i += 8;
                    }
                    i++;
                }
                writer.write(buffer.toString());
                firstLine.delete(0, firstLine.length());
                firstLine.append(currentStr.substring(i));
                nextLine.delete(0, nextLine.length());
            } else {
                writer.write(firstLine.toString());
                firstLine.delete(0, firstLine.length());
                firstLine.append(nextLine);
                nextLine.delete(0, nextLine.length());
            }
        }
    }

    public static byte getCharHex(char c1) {
        if (c1 >= '0' && c1 <= '9') {
            return (byte) (c1 - '0');
        } else if (c1 >= 'a' && c1 <= 'f') {
            return (byte) (c1 - 'a' + 10);
        } else if (c1 >= 'A' && c1 <= 'F') {
            return (byte) (c1 - 'A' + 10);
        }
        return 0;
    }

    public static String decodeURI(String lastAnchor) throws UnsupportedEncodingException {
        if (lastAnchor.indexOf('%') != -1) {
            int i = 0;
            int length = lastAnchor.length();
            StringBuffer buf = new StringBuffer();
            while (i < length) {
                if (lastAnchor.charAt(i) != '%') {
                    buf.append(lastAnchor.charAt(i));
                } else {
                    byte[] chars = new byte[3];
                    chars[0] = (byte) (getCharHex(lastAnchor.charAt(i + 1)) * 16);
                    chars[0] += getCharHex(lastAnchor.charAt(i + 2));
                    chars[1] = (byte) (getCharHex(lastAnchor.charAt(i + 4)) * 16);
                    chars[1] += getCharHex(lastAnchor.charAt(i + 5));
                    chars[2] = (byte) (getCharHex(lastAnchor.charAt(i + 7)) * 16);
                    chars[2] += getCharHex(lastAnchor.charAt(i + 8));
                    buf.append(new String(chars, "utf-8").charAt(0)); //$NON-NLS-1$
                    i += 8;
                }
                i++;
            }
            lastAnchor = buf.toString();
        }
        return lastAnchor;
    }

    public static String decodeURI2(String lastAnchor) throws UnsupportedEncodingException {
        if (lastAnchor.indexOf('%') != -1) {
            int i = 0;
            int length = lastAnchor.length();
            StringBuffer buf = new StringBuffer();
            while (i < length) {
                if (lastAnchor.charAt(i) != '%') {
                    buf.append(lastAnchor.charAt(i));
                } else {
                    byte[] chars = new byte[2];
                    chars[0] = (byte) (getCharHex(lastAnchor.charAt(i + 1)) * 16);
                    chars[0] += getCharHex(lastAnchor.charAt(i + 2));
                    chars[1] = (byte) (getCharHex(lastAnchor.charAt(i + 4)) * 16);
                    chars[1] += getCharHex(lastAnchor.charAt(i + 5));
                    buf.append(new String(chars, "gbk").charAt(0)); //$NON-NLS-1$
                    i += 5;
                }
                i++;
            }
            lastAnchor = buf.toString();
        }
        return lastAnchor;
    }

    public static String byte2HexStr(byte b) {
        int i = b;
        if (i < 0) {
            i += 256;
        }
        int h = i / 16;
        int l = i % 16;
        StringBuffer buf = new StringBuffer();
        if (h < 10) {
            char c = '0';
            c += h;
            buf.append(c);
        } else {
            char c = 'A';
            c += h - 10;
            buf.append(c);
        }
        if (l < 10) {
            char c = '0';
            c += l;
            buf.append(c);
        } else {
            char c = 'A';
            c += l - 10;
            buf.append(c);
        }
        System.out.println(buf.toString());
        return buf.toString();
    }

    public static String decodeURI2GBK(String lastAnchor) throws UnsupportedEncodingException {
            if (lastAnchor.indexOf('%') != -1) {
                int i = 0;
                int length = lastAnchor.length();
                StringBuffer buf = new StringBuffer();
                while (i < length) {
                    if (!(lastAnchor.charAt(i) == '%' && i + 6 < length
                            && lastAnchor.charAt(i + 3) == '%'
                            && lastAnchor.charAt(i + 6) == '%')) {
                        buf.append(lastAnchor.charAt(i));
                    } else {
                        byte[] chars = new byte[3];
                        chars[0] = (byte) (getCharHex(lastAnchor.charAt(i + 1)) * 16);
                        chars[0] += getCharHex(lastAnchor.charAt(i + 2));
                        chars[1] = (byte) (getCharHex(lastAnchor.charAt(i + 4)) * 16);
                        chars[1] += getCharHex(lastAnchor.charAt(i + 5));
                        chars[2] = (byte) (getCharHex(lastAnchor.charAt(i + 7)) * 16);
                        chars[2] += getCharHex(lastAnchor.charAt(i + 8));
    //                    byte[] bytes = new String(chars, "utf-8").getBytes("gbk");  //$NON-NLS-1$//$NON-NLS-2$
    //                    buf.append('%');
    //                    buf.append(byte2HexStr(bytes[0]));
    //                    buf.append('%');
    //                    buf.append(byte2HexStr(bytes[1]));
                        buf.append(new String(chars, "utf-8").charAt(0)); //$NON-NLS-1$
                        i += 8;
                    }
                    i++;
                }
                lastAnchor = buf.toString();
            }
            return lastAnchor;
        }
}