/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package nokogiri.internals.c14n;

import java.io.IOException;
import java.io.OutputStream;
import java.util.Map;

public final class UtfHelper
{

  private
  UtfHelper()
  {
    // complete
  }

  public static void
  writeByte(
    final String str,
    final OutputStream out,
    Map<String, byte[]> cache
  ) throws IOException
  {
    byte[] result = cache.get(str);
    if (result == null) {
      result = getStringInUtf8(str);
      cache.put(str, result);
    }

    out.write(result);
  }

  public static void
  writeCharToUtf8(final char c, final OutputStream out) throws IOException
  {
    if (c < 0x80) {
      out.write(c);
      return;
    }
    if ((c >= 0xD800 && c <= 0xDBFF) || (c >= 0xDC00 && c <= 0xDFFF)) {
      //No Surrogates in sun java
      out.write(0x3f);
      return;
    }
    int bias;
    int write;
    char ch;
    if (c > 0x07FF) {
      ch = (char)(c >>> 12);
      write = 0xE0;
      if (ch > 0) {
        write |= (ch & 0x0F);
      }
      out.write(write);
      write = 0x80;
      bias = 0x3F;
    } else {
      write = 0xC0;
      bias = 0x1F;
    }
    ch = (char)(c >>> 6);
    if (ch > 0) {
      write |= (ch & bias);
    }
    out.write(write);
    out.write(0x80 | ((c) & 0x3F));

  }

  public static void
  writeStringToUtf8(
    final String str,
    final OutputStream out
  ) throws IOException
  {
    final int length = str.length();
    int i = 0;
    char c;
    while (i < length) {
      c = str.charAt(i++);
      if (c < 0x80)  {
        out.write(c);
        continue;
      }
      if ((c >= 0xD800 && c <= 0xDBFF) || (c >= 0xDC00 && c <= 0xDFFF)) {
        //No Surrogates in sun java
        out.write(0x3f);
        continue;
      }
      char ch;
      int bias;
      int write;
      if (c > 0x07FF) {
        ch = (char)(c >>> 12);
        write = 0xE0;
        if (ch > 0) {
          write |= (ch & 0x0F);
        }
        out.write(write);
        write = 0x80;
        bias = 0x3F;
      } else {
        write = 0xC0;
        bias = 0x1F;
      }
      ch = (char)(c >>> 6);
      if (ch > 0) {
        write |= (ch & bias);
      }
      out.write(write);
      out.write(0x80 | ((c) & 0x3F));

    }

  }

  public static byte[]
  getStringInUtf8(final String str)
  {
    final int length = str.length();
    boolean expanded = false;
    byte[] result = new byte[length];
    int i = 0;
    int out = 0;
    char c;
    while (i < length) {
      c = str.charAt(i++);
      if (c < 0x80) {
        result[out++] = (byte)c;
        continue;
      }
      if ((c >= 0xD800 && c <= 0xDBFF) || (c >= 0xDC00 && c <= 0xDFFF)) {
        //No Surrogates in sun java
        result[out++] = 0x3f;
        continue;
      }
      if (!expanded) {
        byte newResult[] = new byte[3 * length];
        System.arraycopy(result, 0, newResult, 0, out);
        result = newResult;
        expanded = true;
      }
      char ch;
      int bias;
      byte write;
      if (c > 0x07FF) {
        ch = (char)(c >>> 12);
        write = (byte)0xE0;
        if (ch > 0) {
          write |= (ch & 0x0F);
        }
        result[out++] = write;
        write = (byte)0x80;
        bias = 0x3F;
      } else {
        write = (byte)0xC0;
        bias = 0x1F;
      }
      ch = (char)(c >>> 6);
      if (ch > 0) {
        write |= (ch & bias);
      }
      result[out++] = write;
      result[out++] = (byte)(0x80 | ((c) & 0x3F));
    }
    if (expanded) {
      byte newResult[] = new byte[out];
      System.arraycopy(result, 0, newResult, 0, out);
      result = newResult;
    }
    return result;
  }
}
