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 : void *state; /* Free field for use by callback implementation */
41 : size_t bytes_left;
42 :
43 : #ifndef PB_NO_ERRMSG
44 : const char *errmsg;
45 : #endif
46 : };
47 :
48 : #ifndef PB_NO_ERRMSG
49 3135798 : #define PB_ISTREAM_EMPTY {0,0,0,0}
50 : #else
51 : #define PB_ISTREAM_EMPTY {0,0,0}
52 : #endif
53 :
54 : /***************************
55 : * Main decoding functions *
56 : ***************************/
57 :
58 : /* Decode a single protocol buffers message from input stream into a C structure.
59 : * Returns true on success, false on any failure.
60 : * The actual struct pointed to by dest must match the description in fields.
61 : * Callback fields of the destination structure must be initialized by caller.
62 : * All other fields will be initialized by this function.
63 : *
64 : * Example usage:
65 : * MyMessage msg = {};
66 : * uint8_t buffer[64];
67 : * pb_istream_t stream;
68 : *
69 : * // ... read some data into buffer ...
70 : *
71 : * stream = pb_istream_from_buffer(buffer, count);
72 : * pb_decode(&stream, MyMessage_fields, &msg);
73 : */
74 : bool pb_decode(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct);
75 :
76 : /* Extended version of pb_decode, with several options to control
77 : * the decoding process:
78 : *
79 : * PB_DECODE_NOINIT: Do not initialize the fields to default values.
80 : * This is slightly faster if you do not need the default
81 : * values and instead initialize the structure to 0 using
82 : * e.g. memset(). This can also be used for merging two
83 : * messages, i.e. combine already existing data with new
84 : * values.
85 : *
86 : * PB_DECODE_DELIMITED: Input message starts with the message size as varint.
87 : * Corresponds to parseDelimitedFrom() in Google's
88 : * protobuf API.
89 : *
90 : * PB_DECODE_NULLTERMINATED: Stop reading when field tag is read as 0. This allows
91 : * reading null terminated messages.
92 : * NOTE: Until nanopb-0.4.0, pb_decode() also allows
93 : * null-termination. This behaviour is not supported in
94 : * most other protobuf implementations, so PB_DECODE_DELIMITED
95 : * is a better option for compatibility.
96 : *
97 : * Multiple flags can be combined with bitwise or (| operator)
98 : */
99 3822153 : #define PB_DECODE_NOINIT 0x01U
100 110235 : #define PB_DECODE_DELIMITED 0x02U
101 0 : #define PB_DECODE_NULLTERMINATED 0x04U
102 : bool pb_decode_ex(pb_istream_t *stream, const pb_msgdesc_t *fields, void *dest_struct, unsigned int flags);
103 :
104 : /* Defines for backwards compatibility with code written before nanopb-0.4.0 */
105 : #define pb_decode_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NOINIT)
106 : #define pb_decode_delimited(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED)
107 : #define pb_decode_delimited_noinit(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_DELIMITED | PB_DECODE_NOINIT)
108 : #define pb_decode_nullterminated(s,f,d) pb_decode_ex(s,f,d, PB_DECODE_NULLTERMINATED)
109 :
110 : /* Release any allocated pointer fields. If you use dynamic allocation, you should
111 : * call this for any successfully decoded message when you are done with it. If
112 : * pb_decode() returns with an error, the message is already released.
113 : */
114 : void pb_release(const pb_msgdesc_t *fields, void *dest_struct);
115 :
116 : /**************************************
117 : * Functions for manipulating streams *
118 : **************************************/
119 :
120 : /* Create an input stream for reading from a memory buffer.
121 : *
122 : * msglen should be the actual length of the message, not the full size of
123 : * allocated buffer.
124 : *
125 : * Alternatively, you can use a custom stream that reads directly from e.g.
126 : * a file or a network socket.
127 : */
128 : pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t msglen);
129 :
130 : /* Function to read from a pb_istream_t. You can use this if you need to
131 : * read some custom header data, or to read data in field callbacks.
132 : */
133 : bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count);
134 :
135 :
136 : /************************************************
137 : * Helper functions for writing field callbacks *
138 : ************************************************/
139 :
140 : /* Decode the tag for the next field in the stream. Gives the wire type and
141 : * field tag. At end of the message, returns false and sets eof to true. */
142 : bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
143 :
144 : /* Skip the field payload data, given the wire type. */
145 : bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
146 :
147 : /* Decode an integer in the varint format. This works for enum, int32,
148 : * int64, uint32 and uint64 field types. */
149 : #ifndef PB_WITHOUT_64BIT
150 : bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
151 : #else
152 : #define pb_decode_varint pb_decode_varint32
153 : #endif
154 :
155 : /* Decode an integer in the varint format. This works for enum, int32,
156 : * and uint32 field types. */
157 : bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
158 :
159 : /* Decode a bool value in varint format. */
160 : bool pb_decode_bool(pb_istream_t *stream, bool *dest);
161 :
162 : /* Decode an integer in the zig-zagged svarint format. This works for sint32
163 : * and sint64. */
164 : #ifndef PB_WITHOUT_64BIT
165 : bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
166 : #else
167 : bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest);
168 : #endif
169 :
170 : /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
171 : * a 4-byte wide C variable. */
172 : bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
173 :
174 : #ifndef PB_WITHOUT_64BIT
175 : /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
176 : * a 8-byte wide C variable. */
177 : bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
178 : #endif
179 :
180 : #ifdef PB_CONVERT_DOUBLE_FLOAT
181 : /* Decode a double value into float variable. */
182 : bool pb_decode_double_as_float(pb_istream_t *stream, float *dest);
183 : #endif
184 :
185 : /* Make a limited-length substream for reading a PB_WT_STRING field. */
186 : bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
187 : bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
188 :
189 : #ifdef __cplusplus
190 : } /* extern "C" */
191 : #endif
192 :
193 : #endif
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