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/*
 * Copyright 2014 Metamarkets Group Inc.
 *
 * Licensed 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 com.metamx.common;

import com.google.common.base.Charsets;
import com.google.common.base.Throwables;
import com.metamx.common.logger.Logger;

import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.IllegalFormatException;

/**
 * As of right now (Dec 2014) the JVM is optimized around String charset variablse instead of Charset passing.
 */
public class StringUtils
{
  @Deprecated // Charset parameters to String are currently slower than the charset's string name
  public static final Charset UTF8_CHARSET = Charsets.UTF_8;
  public static final String UTF8_STRING = com.google.common.base.Charsets.UTF_8.toString();

  public static String fromUtf8(final byte[] bytes)
  {
    try {
      return new String(bytes, UTF8_STRING);
    }
    catch (UnsupportedEncodingException e) {
      // Should never happen
      throw Throwables.propagate(e);
    }
  }

  public static String fromUtf8(final ByteBuffer buffer, final int numBytes)
  {
    final byte[] bytes = new byte[numBytes];
    buffer.get(bytes);
    return fromUtf8(bytes);
  }

  public static String fromUtf8(final ByteBuffer buffer)
  {
    return fromUtf8(buffer, buffer.remaining());
  }

  public static byte[] toUtf8(final String string)
  {
    try {
      return string.getBytes(UTF8_STRING);
    }
    catch (UnsupportedEncodingException e) {
      // Should never happen
      throw Throwables.propagate(e);
    }
  }

  public static String safeFormat(String message, Object... formatArgs)
  {
    if(formatArgs == null || formatArgs.length == 0) {
      return message;
    }
    try {
      return String.format(message, formatArgs);
    }
    catch (IllegalFormatException e) {
      StringBuilder bob = new StringBuilder(message);
      for (Object formatArg : formatArgs) {
        bob.append("; ").append(formatArg);
      }
      return bob.toString();
    }
  }

  /**
   * Replaces all occurrences of the given char in the given string with the given replacement string. This method is an
   * optimal version of {@link String#replace(CharSequence, CharSequence) s.replace("c", replacement)}.
   */
  public static String replaceChar(String s, char c, String replacement)
  {
    int pos = s.indexOf(c);
    if (pos < 0) {
      return s;
    }
    StringBuilder sb = new StringBuilder(s.length() - 1 + replacement.length());
    int prevPos = 0;
    do {
      sb.append(s, prevPos, pos);
      sb.append(replacement);
      prevPos = pos + 1;
      pos = s.indexOf(c, pos + 1);
    } while (pos > 0);
    sb.append(s, prevPos, s.length());
    return sb.toString();
  }
}