Line data Source code
1 : /* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
2 : * The main function is pb_decode. You also need an input stream, and the
3 : * field descriptions created by nanopb_generator.py.
4 : */
5 :
6 : #ifndef PB_DECODE_H_INCLUDED
7 : #define PB_DECODE_H_INCLUDED
8 :
9 : #include "pb_firedancer.h"
10 :
11 : #ifdef __cplusplus
12 : extern "C" {
13 : #endif
14 :
15 : /* Structure for defining custom input streams. You will need to provide
16 : * a callback function to read the bytes from your storage, which can be
17 : * for example a file or a network socket.
18 : *
19 : * The callback must conform to these rules:
20 : *
21 : * 1) Return false on IO errors. This will cause decoding to abort.
22 : * 2) You can use state to store your own data (e.g. buffer pointer),
23 : * and rely on pb_read to verify that no-body reads past bytes_left.
24 : * 3) Your callback may be used with substreams, in which case bytes_left
25 : * is different than from the main stream. Don't use bytes_left to compute
26 : * any pointers.
27 : */
28 : struct pb_istream_s
29 : {
30 : #ifdef PB_BUFFER_ONLY
31 : /* Callback pointer is not used in buffer-only configuration.
32 : * Having an int pointer here allows binary compatibility but
33 : * gives an error if someone tries to assign callback function.
34 : */
35 : int *callback;
36 : #else
37 : bool (*callback)(pb_istream_t *stream, pb_byte_t *buf, size_t count);
38 : #endif
39 :
40 : /* state is a free field for use of the callback function defined above.
41 : * Note that when pb_istream_from_buffer() is used, it reserves this field
42 : * for its own use.
43 : */
44 : void *state;
45 :
46 : /* Maximum number of bytes left in this stream. Callback can report
47 : * EOF before this limit is reached. Setting a limit is recommended
48 : * when decoding directly from file or network streams to avoid
49 : * denial-of-service by excessively long messages.
50 : */
51 : size_t bytes_left;
52 :
53 : #ifndef PB_NO_ERRMSG
54 : /* Pointer to constant (ROM) string when decoding function returns error */
55 : const char *errmsg;
56 : #endif
57 : };
58 :
59 : #ifndef PB_NO_ERRMSG
60 2842107 : #define PB_ISTREAM_EMPTY {0,0,0,0}
61 : #else
62 : #define PB_ISTREAM_EMPTY {0,0,0}
63 : #endif
64 :
65 : /***************************
66 : * Main decoding functions *
67 : ***************************/
68 :
69 : /* Decode a single protocol buffers message from input stream into a C structure.
70 : * Returns true on success, false on any failure.
71 : * The actual struct pointed to by dest must match the description in fields.
72 : * Callback fields of the destination structure must be initialized by caller.
73 : * All other fields will be initialized by this function.
74 : *
75 : * Example usage:
76 : * MyMessage msg = {};
77 : * uint8_t buffer[64];
78 : * pb_istream_t stream;
79 : *
80 : * // ... read some data into buffer ...
81 : *
82 : * stream = pb_istream_from_buffer(buffer, count);
83 : * pb_decode(&stream, MyMessage_fields, &msg);
84 : */
85 : bool pb_decode(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct);
86 :
87 : /* Extended version of pb_decode, with several options to control
88 : * the decoding process:
89 : *
90 : * PB_DECODE_NOINIT: Do not initialize the fields to default values.
91 : * This is slightly faster if you do not need the default
92 : * values and instead initialize the structure to 0 using
93 : * e.g. memset(). This can also be used for merging two
94 : * messages, i.e. combine already existing data with new
95 : * values.
96 : *
97 : * PB_DECODE_DELIMITED: Input message starts with the message size as varint.
98 : * Corresponds to parseDelimitedFrom() in Google's
99 : * protobuf API.
100 : *
101 : * PB_DECODE_NULLTERMINATED: Stop reading when field tag is read as 0. This allows
102 : * reading null terminated messages.
103 : * NOTE: Until nanopb-0.4.0, pb_decode() also allows
104 : * null-termination. This behaviour is not supported in
105 : * most other protobuf implementations, so PB_DECODE_DELIMITED
106 : * is a better option for compatibility.
107 : *
108 : * Multiple flags can be combined with bitwise or (| operator)
109 : */
110 7665576 : #define PB_DECODE_NOINIT 0x01U
111 408450 : #define PB_DECODE_DELIMITED 0x02U
112 0 : #define PB_DECODE_NULLTERMINATED 0x04U
113 : bool pb_decode_ex(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct, unsigned int flags);
114 :
115 : /* Defines for backwards compatibility with code written before nanopb-0.4.0 */
116 : #define pb_decode_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NOINIT)
117 : #define pb_decode_delimited(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED)
118 : #define pb_decode_delimited_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED | PB_DECODE_NOINIT)
119 : #define pb_decode_nullterminated(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NULLTERMINATED)
120 :
121 : /* Release any allocated pointer fields. If you use dynamic allocation, you should
122 : * call this for any successfully decoded message when you are done with it. If
123 : * pb_decode() returns with an error, the message is already released.
124 : */
125 : void pb_release(const pb_msgdesc_t *fields, void *dest_struct);
126 :
127 : /**************************************
128 : * Functions for manipulating streams *
129 : **************************************/
130 :
131 : /* Create an input stream for reading from a memory buffer.
132 : *
133 : * msglen should be the actual length of the message, not the full size of
134 : * allocated buffer.
135 : *
136 : * Alternatively, you can use a custom stream that reads directly from e.g.
137 : * a file or a network socket.
138 : */
139 : pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t msglen);
140 :
141 : /* Function to read from a pb_istream_t. You can use this if you need to
142 : * read some custom header data, or to read data in field callbacks.
143 : */
144 : bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count);
145 :
146 :
147 : /************************************************
148 : * Helper functions for writing field callbacks *
149 : ************************************************/
150 :
151 : /* Decode the tag for the next field in the stream. Gives the wire type and
152 : * field tag. At end of the message, returns false and sets eof to true. */
153 : bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
154 :
155 : /* Skip the field payload data, given the wire type. */
156 : bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
157 :
158 : /* Decode an integer in the varint format. This works for enum, int32,
159 : * int64, uint32 and uint64 field types. */
160 : #ifndef PB_WITHOUT_64BIT
161 : bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
162 : #else
163 : #define pb_decode_varint pb_decode_varint32
164 : #endif
165 :
166 : /* Decode an integer in the varint format. This works for enum, int32,
167 : * and uint32 field types. */
168 : bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
169 :
170 : /* Decode a bool value in varint format. */
171 : bool pb_decode_bool(pb_istream_t *stream, bool *dest);
172 :
173 : /* Decode an integer in the zig-zagged svarint format. This works for sint32
174 : * and sint64. */
175 : #ifndef PB_WITHOUT_64BIT
176 : bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
177 : #else
178 : bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest);
179 : #endif
180 :
181 : /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
182 : * a 4-byte wide C variable. */
183 : bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
184 :
185 : #ifndef PB_WITHOUT_64BIT
186 : /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
187 : * a 8-byte wide C variable. */
188 : bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
189 : #endif
190 :
191 : #ifdef PB_CONVERT_DOUBLE_FLOAT
192 : /* Decode a double value into float variable. */
193 : bool pb_decode_double_as_float(pb_istream_t *stream, float *dest);
194 : #endif
195 :
196 : /* Make a limited-length substream for reading a PB_WT_STRING field. */
197 : bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
198 : bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
199 :
200 : #ifdef __cplusplus
201 : } /* extern "C" */
202 : #endif
203 :
204 : #endif
|
