1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc.  All rights reserved.
3// https://developers.google.com/protocol-buffers/
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are
7// met:
8//
9//     * Redistributions of source code must retain the above copyright
10// notice, this list of conditions and the following disclaimer.
11//     * Redistributions in binary form must reproduce the above
12// copyright notice, this list of conditions and the following disclaimer
13// in the documentation and/or other materials provided with the
14// distribution.
15//     * Neither the name of Google Inc. nor the names of its
16// contributors may be used to endorse or promote products derived from
17// this software without specific prior written permission.
18//
19// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31package com.google.protobuf;
32
33import java.io.IOException;
34
35/**
36 * This class is used internally by the Protocol Buffer library and generated
37 * message implementations.  It is public only because those generated messages
38 * do not reside in the {@code protobuf} package.  Others should not use this
39 * class directly.
40 *
41 * This class contains constants and helper functions useful for dealing with
42 * the Protocol Buffer wire format.
43 *
44 * @author kenton@google.com Kenton Varda
45 */
46public final class WireFormat {
47  // Do not allow instantiation.
48  private WireFormat() {}
49
50  public static final int WIRETYPE_VARINT           = 0;
51  public static final int WIRETYPE_FIXED64          = 1;
52  public static final int WIRETYPE_LENGTH_DELIMITED = 2;
53  public static final int WIRETYPE_START_GROUP      = 3;
54  public static final int WIRETYPE_END_GROUP        = 4;
55  public static final int WIRETYPE_FIXED32          = 5;
56
57  static final int TAG_TYPE_BITS = 3;
58  static final int TAG_TYPE_MASK = (1 << TAG_TYPE_BITS) - 1;
59
60  /** Given a tag value, determines the wire type (the lower 3 bits). */
61  public static int getTagWireType(final int tag) {
62    return tag & TAG_TYPE_MASK;
63  }
64
65  /** Given a tag value, determines the field number (the upper 29 bits). */
66  public static int getTagFieldNumber(final int tag) {
67    return tag >>> TAG_TYPE_BITS;
68  }
69
70  /** Makes a tag value given a field number and wire type. */
71  static int makeTag(final int fieldNumber, final int wireType) {
72    return (fieldNumber << TAG_TYPE_BITS) | wireType;
73  }
74
75  /**
76   * Lite equivalent to {@link Descriptors.FieldDescriptor.JavaType}.  This is
77   * only here to support the lite runtime and should not be used by users.
78   */
79  public enum JavaType {
80    INT(0),
81    LONG(0L),
82    FLOAT(0F),
83    DOUBLE(0D),
84    BOOLEAN(false),
85    STRING(""),
86    BYTE_STRING(ByteString.EMPTY),
87    ENUM(null),
88    MESSAGE(null);
89
90    JavaType(final Object defaultDefault) {
91      this.defaultDefault = defaultDefault;
92    }
93
94    /**
95     * The default default value for fields of this type, if it's a primitive
96     * type.
97     */
98    Object getDefaultDefault() {
99      return defaultDefault;
100    }
101
102    private final Object defaultDefault;
103  }
104
105  /**
106   * Lite equivalent to {@link Descriptors.FieldDescriptor.Type}.  This is
107   * only here to support the lite runtime and should not be used by users.
108   */
109  public enum FieldType {
110    DOUBLE  (JavaType.DOUBLE     , WIRETYPE_FIXED64         ),
111    FLOAT   (JavaType.FLOAT      , WIRETYPE_FIXED32         ),
112    INT64   (JavaType.LONG       , WIRETYPE_VARINT          ),
113    UINT64  (JavaType.LONG       , WIRETYPE_VARINT          ),
114    INT32   (JavaType.INT        , WIRETYPE_VARINT          ),
115    FIXED64 (JavaType.LONG       , WIRETYPE_FIXED64         ),
116    FIXED32 (JavaType.INT        , WIRETYPE_FIXED32         ),
117    BOOL    (JavaType.BOOLEAN    , WIRETYPE_VARINT          ),
118    STRING  (JavaType.STRING     , WIRETYPE_LENGTH_DELIMITED) {
119      @Override
120      public boolean isPackable() {
121        return false; }
122    },
123    GROUP   (JavaType.MESSAGE    , WIRETYPE_START_GROUP     ) {
124      @Override
125      public boolean isPackable() {
126        return false; }
127    },
128    MESSAGE (JavaType.MESSAGE    , WIRETYPE_LENGTH_DELIMITED) {
129      @Override
130      public boolean isPackable() {
131        return false; }
132    },
133    BYTES   (JavaType.BYTE_STRING, WIRETYPE_LENGTH_DELIMITED) {
134      @Override
135      public boolean isPackable() {
136        return false; }
137    },
138    UINT32  (JavaType.INT        , WIRETYPE_VARINT          ),
139    ENUM    (JavaType.ENUM       , WIRETYPE_VARINT          ),
140    SFIXED32(JavaType.INT        , WIRETYPE_FIXED32         ),
141    SFIXED64(JavaType.LONG       , WIRETYPE_FIXED64         ),
142    SINT32  (JavaType.INT        , WIRETYPE_VARINT          ),
143    SINT64  (JavaType.LONG       , WIRETYPE_VARINT          );
144
145    FieldType(final JavaType javaType, final int wireType) {
146      this.javaType = javaType;
147      this.wireType = wireType;
148    }
149
150    private final JavaType javaType;
151    private final int wireType;
152
153    public JavaType getJavaType() { return javaType; }
154    public int getWireType() { return wireType; }
155
156    public boolean isPackable() { return true; }
157  }
158
159  // Field numbers for fields in MessageSet wire format.
160  static final int MESSAGE_SET_ITEM    = 1;
161  static final int MESSAGE_SET_TYPE_ID = 2;
162  static final int MESSAGE_SET_MESSAGE = 3;
163
164  // Tag numbers.
165  static final int MESSAGE_SET_ITEM_TAG =
166    makeTag(MESSAGE_SET_ITEM, WIRETYPE_START_GROUP);
167  static final int MESSAGE_SET_ITEM_END_TAG =
168    makeTag(MESSAGE_SET_ITEM, WIRETYPE_END_GROUP);
169  static final int MESSAGE_SET_TYPE_ID_TAG =
170    makeTag(MESSAGE_SET_TYPE_ID, WIRETYPE_VARINT);
171  static final int MESSAGE_SET_MESSAGE_TAG =
172    makeTag(MESSAGE_SET_MESSAGE, WIRETYPE_LENGTH_DELIMITED);
173
174  /**
175   * Validation level for handling incoming string field data which potentially
176   * contain non-UTF8 bytes.
177   */
178  enum Utf8Validation {
179    /** Eagerly parses to String; silently accepts invalid UTF8 bytes. */
180    LOOSE {
181      @Override
182      Object readString(CodedInputStream input) throws IOException {
183        return input.readString();
184      }
185    },
186    /** Eagerly parses to String; throws an IOException on invalid bytes. */
187    STRICT {
188      @Override
189      Object readString(CodedInputStream input) throws IOException {
190        return input.readStringRequireUtf8();
191      }
192    },
193    /** Keep data as ByteString; validation/conversion to String is lazy. */
194    LAZY {
195      @Override
196      Object readString(CodedInputStream input) throws IOException {
197        return input.readBytes();
198      }
199    };
200
201    /** Read a string field from the input with the proper UTF8 validation. */
202    abstract Object readString(CodedInputStream input) throws IOException;
203  }
204
205  /**
206   * Read a field of any primitive type for immutable messages from a
207   * CodedInputStream. Enums, groups, and embedded messages are not handled by
208   * this method.
209   *
210   * @param input The stream from which to read.
211   * @param type Declared type of the field.
212   * @param utf8Validation Different string UTF8 validation level for handling
213   *                       string fields.
214   * @return An object representing the field's value, of the exact
215   *         type which would be returned by
216   *         {@link Message#getField(Descriptors.FieldDescriptor)} for
217   *         this field.
218   */
219  static Object readPrimitiveField(
220      CodedInputStream input,
221      FieldType type,
222      Utf8Validation utf8Validation) throws IOException {
223    switch (type) {
224      case DOUBLE  : return input.readDouble  ();
225      case FLOAT   : return input.readFloat   ();
226      case INT64   : return input.readInt64   ();
227      case UINT64  : return input.readUInt64  ();
228      case INT32   : return input.readInt32   ();
229      case FIXED64 : return input.readFixed64 ();
230      case FIXED32 : return input.readFixed32 ();
231      case BOOL    : return input.readBool    ();
232      case BYTES   : return input.readBytes   ();
233      case UINT32  : return input.readUInt32  ();
234      case SFIXED32: return input.readSFixed32();
235      case SFIXED64: return input.readSFixed64();
236      case SINT32  : return input.readSInt32  ();
237      case SINT64  : return input.readSInt64  ();
238
239      case STRING  : return utf8Validation.readString(input);
240      case GROUP:
241        throw new IllegalArgumentException(
242          "readPrimitiveField() cannot handle nested groups.");
243      case MESSAGE:
244        throw new IllegalArgumentException(
245          "readPrimitiveField() cannot handle embedded messages.");
246      case ENUM:
247        // We don't handle enums because we don't know what to do if the
248        // value is not recognized.
249        throw new IllegalArgumentException(
250          "readPrimitiveField() cannot handle enums.");
251    }
252
253    throw new RuntimeException(
254      "There is no way to get here, but the compiler thinks otherwise.");
255  }
256}
257