Avro C++
Decoder.hh
Go to the documentation of this file.
1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements. See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership. The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the
7  * "License"); you may not use this file except in compliance
8  * with the License. You may obtain a copy of the License at
9  *
10  * https://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 
19 #ifndef avro_Decoder_hh__
20 #define avro_Decoder_hh__
21 
22 #include "Config.hh"
23 #include <stdint.h>
24 #include <string>
25 #include <vector>
26 #include <memory>
27 
28 #include "ValidSchema.hh"
29 #include "Stream.hh"
30 
41 
42 namespace avro {
43 
48 class AVRO_DECL Decoder {
49 public:
50  virtual ~Decoder() { };
54  virtual void init(InputStream& is) = 0;
55 
57  virtual void decodeNull() = 0;
58 
60  virtual bool decodeBool() = 0;
61 
63  virtual int32_t decodeInt() = 0;
64 
66  virtual int64_t decodeLong() = 0;
67 
69  virtual float decodeFloat() = 0;
70 
72  virtual double decodeDouble() = 0;
73 
75  std::string decodeString() {
76  std::string result;
77  decodeString(result);
78  return result;
79  }
80 
84  virtual void decodeString(std::string& value) = 0;
85 
87  virtual void skipString() = 0;
88 
90  std::vector<uint8_t> decodeBytes() {
91  std::vector<uint8_t> result;
92  decodeBytes(result);
93  return result;
94  }
95 
98  virtual void decodeBytes(std::vector<uint8_t>& value) = 0;
99 
101  virtual void skipBytes() = 0;
102 
109  std::vector<uint8_t> decodeFixed(size_t n) {
110  std::vector<uint8_t> result;
111  decodeFixed(n, result);
112  return result;
113  }
114 
121  virtual void decodeFixed(size_t n, std::vector<uint8_t>& value) = 0;
122 
124  virtual void skipFixed(size_t n) = 0;
125 
127  virtual size_t decodeEnum() = 0;
128 
130  virtual size_t arrayStart() = 0;
131 
133  virtual size_t arrayNext() = 0;
134 
139  virtual size_t skipArray() = 0;
140 
142  virtual size_t mapStart() = 0;
143 
145  virtual size_t mapNext() = 0;
146 
151  virtual size_t skipMap() = 0;
152 
154  virtual size_t decodeUnionIndex() = 0;
155 
171  virtual void drain() = 0;
172 };
173 
177 typedef std::shared_ptr<Decoder> DecoderPtr;
178 
183 class AVRO_DECL ResolvingDecoder : public Decoder {
184 public:
190  virtual const std::vector<size_t>& fieldOrder() = 0;
191 };
192 
196 typedef std::shared_ptr<ResolvingDecoder> ResolvingDecoderPtr;
200 AVRO_DECL DecoderPtr binaryDecoder();
201 
206 AVRO_DECL DecoderPtr validatingDecoder(const ValidSchema& schema,
207  const DecoderPtr& base);
208 
212 AVRO_DECL DecoderPtr jsonDecoder(const ValidSchema& schema);
213 
220 AVRO_DECL ResolvingDecoderPtr resolvingDecoder(const ValidSchema& writer,
221  const ValidSchema& reader, const DecoderPtr& base);
222 
223 
224 } // namespace avro
225 
226 #endif
std::vector< uint8_t > decodeBytes()
Decodes arbitray binary data from the current stream.
Definition: Decoder.hh:90
A bunch of templates and specializations for encoding and decoding specific types.
Definition: AvroParse.hh:30
AVRO_DECL ResolvingDecoderPtr resolvingDecoder(const ValidSchema &writer, const ValidSchema &reader, const DecoderPtr &base)
Returns a decoder that decodes avro data from base written according to writerSchema and resolves aga...
ResolvingDecoder is derived from Decoder, with an additional function to obtain the field ordering of...
Definition: Decoder.hh:183
AVRO_DECL DecoderPtr validatingDecoder(const ValidSchema &schema, const DecoderPtr &base)
Returns an decoder that validates sequence of calls to an underlying Decoder against the given schema...
AVRO_DECL DecoderPtr jsonDecoder(const ValidSchema &schema)
Returns an decoder that can decode Avro standard for JSON.
std::shared_ptr< Decoder > DecoderPtr
Shared pointer to Decoder.
Definition: Decoder.hh:177
std::vector< uint8_t > decodeFixed(size_t n)
Decodes fixed length binary from the current stream.
Definition: Decoder.hh:109
A ValidSchema is basically a non-mutable Schema that has passed some minumum of sanity checks...
Definition: ValidSchema.hh:40
A no-copy input stream.
Definition: Stream.hh:36
AVRO_DECL DecoderPtr binaryDecoder()
Returns an decoder that can decode binary Avro standard.
std::string decodeString()
Decodes a UTF-8 string from the current stream.
Definition: Decoder.hh:75
Decoder is an interface implemented by every decoder capable of decoding Avro data.
Definition: Decoder.hh:48
std::shared_ptr< ResolvingDecoder > ResolvingDecoderPtr
Shared pointer to ResolvingDecoder.
Definition: Decoder.hh:196