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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the License. You may obtain a copy of the License at:
    7    *
    8    *   http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.handler.codec.marshalling;
    17
    18  import java.io.IOException;
    19
    20  import org.jboss.marshalling.ByteInput;
    21
    22  /**
    23   * {@link ByteInput} implementation which wraps another {@link ByteInput} and throws a {@link TooBigObjectException}
    24   * if the read limit was reached.
    25   *
    26   *
    27   */
    28  class LimitingByteInput implements ByteInput {
    29
    30      // Use a static instance here to remove the overhead of fillStacktrace
    31      private static final TooBigObjectException EXCEPTION = new TooBigObjectException();
    32
    33      private final ByteInput input;
    34      private final long limit;
    35      private long read;
    36
    37      public LimitingByteInput(ByteInput input, long limit) {
    38          if (limit <= 0) {
    39              throw new IllegalArgumentException("The limit MUST be > 0");
    40          }
    41          this.input = input;
    42          this.limit = limit;
    43      }
    44
    45      public void close() throws IOException {
    46          // Nothing todo
    47      }
    48
    49      public int available() throws IOException {
    50          int available = input.available();
    51          int readable = readable(available);
    52          return readable;
    53      }
    54
    55      public int read() throws IOException {
    56          int readable = readable(1);
    57          if (readable > 0) {
    58              int b = input.read();
    59              read++;
    60              return b;
    61          } else {
    62              throw EXCEPTION;
    63          }
    64      }
    65
    66      public int read(byte[] array) throws IOException {
    67          return read(array, 0, array.length);
    68      }
    69
    70      public int read(byte[] array, int offset, int length) throws IOException {
    71          int readable = readable(length);
    72          if (readable > 0) {
    73              int i = input.read(array, offset, readable);
    74              read += i;
    75              return i;
    76          } else {
    77              throw EXCEPTION;
    78          }
    79      }
    80
    81      public long skip(long bytes) throws IOException {
    82          int readable = readable((int) bytes);
    83          if (readable > 0) {
    84              long i = input.skip(readable);
    85              read += i;
    86              return i;
    87          } else {
    88              throw EXCEPTION;
    89          }
    90      }
    91
    92      private int readable(int length) {
    93          return (int) Math.min(length, limit - read);
    94      }
    95
    96      /**
    97       * Exception that will get thrown if the {@link Object} is to big to unmarshall
    98       *
    99       */
    100     static final class TooBigObjectException extends IOException {
    101
    102         /**
    103          *
    104          */
    105         private static final long serialVersionUID = 1L;
    106
    107     }
    108 }