4 /* pb_encode.h: Functions to encode protocol buffers. Depends on pb_encode.c.
5 * The main function is pb_encode. You also need an output stream, structures
6 * and their field descriptions (just like with pb_decode).
12 /* Lightweight output stream.
13 * You can provide callback for writing or use pb_ostream_from_buffer.
15 * Alternatively, callback can be NULL in which case the stream will just
16 * count the number of bytes that would have been written. In this case
17 * max_size is not checked.
20 * 1) Return false on IO errors. This will cause encoding to abort.
22 * 2) You can use state to store your own data (e.g. buffer pointer).
24 * 3) pb_write will update bytes_written after your callback runs.
26 * 4) Substreams will modify max_size and bytes_written. Don't use them to
27 * calculate any pointers.
31 bool (*callback)(pb_ostream_t *stream, const uint8_t *buf, size_t count);
32 void *state; /* Free field for use by callback implementation */
33 size_t max_size; /* Limit number of output bytes written (or use SIZE_MAX). */
37 pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize);
38 bool pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count);
40 /* Encode struct to given output stream.
41 * Returns true on success, false on any failure.
42 * The actual struct pointed to by src_struct must match the description in fields.
43 * All required fields in the struct are assumed to have been filled in.
45 bool pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);
47 /* --- Helper functions ---
48 * You may want to use these from your caller or callbacks.
51 /* Encode field header based on LTYPE and field number defined in the field structure.
52 * Call this from the callback before writing out field contents. */
53 bool pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field);
55 /* Encode field header by manually specifing wire type. You need to use this if
56 * you want to write out packed arrays from a callback field. */
57 bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number);
59 /* Encode an integer in the varint format.
60 * This works for bool, enum, int32, int64, uint32 and uint64 field types. */
61 bool pb_encode_varint(pb_ostream_t *stream, uint64_t value);
63 /* Encode an integer in the zig-zagged svarint format.
64 * This works for sint32 and sint64. */
65 bool pb_encode_svarint(pb_ostream_t *stream, int64_t value);
67 /* Encode a string or bytes type field. For strings, pass strlen(s) as size. */
68 bool pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size);
70 /* Encode a fixed32, sfixed32 or float value.
71 * You need to pass a pointer to a 4-byte wide C variable. */
72 bool pb_encode_fixed32(pb_ostream_t *stream, const void *value);
74 /* Encode a fixed64, sfixed64 or double value.
75 * You need to pass a pointer to a 8-byte wide C variable. */
76 bool pb_encode_fixed64(pb_ostream_t *stream, const void *value);
78 /* Encode a submessage field.
79 * You need to pass the pb_field_t array and pointer to struct, just like with pb_encode().
80 * This internally encodes the submessage twice, first to calculate message size and then to actually write it out.
82 bool pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);
84 /* --- Internal functions ---
85 * These functions are not terribly useful for the average library user, but
86 * are exported to make the unit testing and extending nanopb easier.
89 #ifdef NANOPB_INTERNALS
90 bool pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
91 bool pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
92 bool pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src);
93 bool pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src);
94 bool pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src);
95 bool pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src);
98 /* This function is not recommended for new programs. Use pb_encode_submessage()
99 * instead, it has the same functionality with a less confusing interface. */
100 bool pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src);