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.
15 /***************************
16 * Main decoding functions *
17 ***************************/
19 /* Decode a single protocol buffers message from input stream into a C structure.
20 * Returns true on success, false on any failure.
21 * The actual struct pointed to by dest must match the description in fields.
22 * Callback fields of the destination structure must be initialized by caller.
23 * All other fields will be initialized by this function.
28 * pb_istream_t stream;
30 * // ... read some data into buffer ...
32 * stream = pb_istream_from_buffer(buffer, count);
33 * pb_decode(&stream, MyMessage_fields, &msg);
35 bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
37 /* Same as pb_decode, except does not initialize the destination structure
38 * to default values. This is slightly faster if you need no default values
39 * and just do memset(struct, 0, sizeof(struct)) yourself.
41 * This can also be used for 'merging' two messages, i.e. update only the
42 * fields that exist in the new message.
44 bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
47 /**************************************
48 * Functions for manipulating streams *
49 **************************************/
51 /* Create an input stream for reading from a memory buffer.
53 * Alternatively, you can use a custom stream that reads directly from e.g.
54 * a file or a network socket.
56 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
58 /* Function to read from a pb_istream_t. You can use this if you need to
59 * read some custom header data, or to read data in field callbacks.
61 bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
63 /* Structure for defining custom input streams. You will need to provide
64 * a callback function to read the bytes from your storage, which can be
65 * for example a file or a network socket.
67 * The callback must conform to these rules:
69 * 1) Return false on IO errors. This will cause decoding to abort.
70 * 2) You can use state to store your own data (e.g. buffer pointer),
71 * and rely on pb_read to verify that no-body reads past bytes_left.
72 * 3) Your callback may be used with substreams, in which case bytes_left
73 * is different than from the main stream. Don't use bytes_left to compute
79 /* Callback pointer is not used in buffer-only configuration.
80 * Having an int pointer here allows binary compatibility but
81 * gives an error if someone tries to assign callback function.
85 bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count);
88 void *state; /* Free field for use by callback implementation */
97 /************************************************
98 * Helper functions for writing field callbacks *
99 ************************************************/
101 /* Decode the tag for the next field in the stream. Gives the wire type and
102 * field tag. At end of the message, returns false and sets eof to true. */
103 bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
105 /* Skip the field payload data, given the wire type. */
106 bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
108 /* Decode an integer in the varint format. This works for bool, enum, int32,
109 * int64, uint32 and uint64 field types. */
110 bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
112 /* Decode an integer in the zig-zagged svarint format. This works for sint32
114 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
116 /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
117 * a 4-byte wide C variable. */
118 bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
120 /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
121 * a 8-byte wide C variable. */
122 bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
124 /* Make a limited-length substream for reading a PB_WT_STRING field. */
125 bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
126 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
129 /*******************************
130 * Internal / legacy functions *
131 *******************************/
133 #ifdef NANOPB_INTERNALS
134 bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
135 bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
136 bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
137 bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
139 bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
140 bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
141 bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
143 bool pb_skip_varint(pb_istream_t *stream);
144 bool pb_skip_string(pb_istream_t *stream);