hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/FastNumberFormat.java

/**
 * 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 org.apache.hadoop.util;

/**
 * Fast thread-safe version of NumberFormat
 */
public class FastNumberFormat {

  public static StringBuilder format(StringBuilder sb, long value, int minimumDigits) {
    if (value < 0) {
      sb.append('-');
      value = -value;
    }

    long tmp = value;
    do {
      tmp /= 10;
    } while (--minimumDigits > 0 && tmp > 0);

    for (int i = minimumDigits; i > 0; --i) {
      sb.append('0');
    }

    sb.append(value);
    return sb;
  }
}