4 /* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
5 * The main function is pb_decode. You will also need to create an input
6 * stream, which is easiest to do with pb_istream_from_buffer().
8 * You also need structures and their corresponding pb_field_t descriptions.
9 * These are usually generated from .proto-files with a script.
15 /* Lightweight input stream.
16 * You can provide a callback function for reading or use
17 * pb_istream_from_buffer.
20 * 1) Return false on IO errors. This will cause decoding to abort.
22 * 2) If buf is NULL, read but don't store bytes ("skip input").
24 * 3) You can use state to store your own data (e.g. buffer pointer),
25 * and rely on pb_read to verify that no-body reads past bytes_left.
27 * 4) Your callback may be used with substreams, in which case bytes_left
28 * is different than from the main stream. Don't use bytes_left to compute
33 bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count);
34 void *state; /* Free field for use by callback implementation */
42 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
43 bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
45 /* Decode from stream to destination struct.
46 * Returns true on success, false on any failure.
47 * The actual struct pointed to by dest must match the description in fields.
49 bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
51 /* Same as pb_decode, except does not initialize the destination structure
52 * to default values. This is slightly faster if you need no default values
53 * and just do memset(struct, 0, sizeof(struct)) yourself.
55 bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
57 /* --- Helper functions ---
58 * You may want to use these from your caller or callbacks.
61 /* Decode the tag for the next field in the stream. Gives the wire type and
62 * field tag. At end of the message, returns false and sets eof to true. */
63 bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
65 /* Skip the field payload data, given the wire type. */
66 bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
68 /* Decode an integer in the varint format. This works for bool, enum, int32,
69 * int64, uint32 and uint64 field types. */
70 bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
72 /* Decode an integer in the zig-zagged svarint format. This works for sint32
74 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
76 /* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to
77 * a 4-byte wide C variable. */
78 bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
80 /* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to
81 * a 8-byte wide C variable. */
82 bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
84 /* Make a limited-length substream for reading a PB_WT_STRING field. */
85 bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
86 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
88 /* --- Internal functions ---
89 * These functions are not terribly useful for the average library user, but
90 * are exported to make the unit testing and extending nanopb easier.
93 #ifdef NANOPB_INTERNALS
94 bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
95 bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
96 bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
97 bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
99 bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
100 bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
101 bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
103 bool pb_skip_varint(pb_istream_t *stream);
104 bool pb_skip_string(pb_istream_t *stream);