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 /* 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.
19 * The callback must conform to these rules:
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
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.
37 bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count);
40 void *state; /* Free field for use by callback implementation */
48 /***************************
49 * Main decoding functions *
50 ***************************/
52 /* Decode a single protocol buffers message from input stream into a C structure.
53 * Returns true on success, false on any failure.
54 * The actual struct pointed to by dest must match the description in fields.
55 * Callback fields of the destination structure must be initialized by caller.
56 * All other fields will be initialized by this function.
61 * pb_istream_t stream;
63 * // ... read some data into buffer ...
65 * stream = pb_istream_from_buffer(buffer, count);
66 * pb_decode(&stream, MyMessage_fields, &msg);
68 bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
70 /* Same as pb_decode, except does not initialize the destination structure
71 * to default values. This is slightly faster if you need no default values
72 * and just do memset(struct, 0, sizeof(struct)) yourself.
74 * This can also be used for 'merging' two messages, i.e. update only the
75 * fields that exist in the new message.
77 bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
79 /* Same as pb_decode, except expects the stream to start with the message size
80 * encoded as varint. Corresponds to parseDelimitedFrom() in Google's
83 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
86 /**************************************
87 * Functions for manipulating streams *
88 **************************************/
90 /* Create an input stream for reading from a memory buffer.
92 * Alternatively, you can use a custom stream that reads directly from e.g.
93 * a file or a network socket.
95 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
97 /* Function to read from a pb_istream_t. You can use this if you need to
98 * read some custom header data, or to read data in field callbacks.
100 bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
103 /************************************************
104 * Helper functions for writing field callbacks *
105 ************************************************/
107 /* Decode the tag for the next field in the stream. Gives the wire type and
108 * field tag. At end of the message, returns false and sets eof to true. */
109 bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
111 /* Skip the field payload data, given the wire type. */
112 bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
114 /* Decode an integer in the varint format. This works for bool, enum, int32,
115 * int64, uint32 and uint64 field types. */
116 bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
118 /* Decode an integer in the zig-zagged svarint format. This works for sint32
120 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
122 /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
123 * a 4-byte wide C variable. */
124 bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
126 /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
127 * a 8-byte wide C variable. */
128 bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
130 /* Make a limited-length substream for reading a PB_WT_STRING field. */
131 bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
132 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
135 /*******************************
136 * Internal / legacy functions *
137 *******************************/
139 #ifdef NANOPB_INTERNALS
140 bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
141 bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
142 bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
143 bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
145 bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
146 bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
147 bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
149 bool pb_skip_varint(pb_istream_t *stream);
150 bool pb_skip_string(pb_istream_t *stream);