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).
15 /* Lightweight output stream.
16 * You can provide callback for writing or use pb_ostream_from_buffer.
18 * Alternatively, callback can be NULL in which case the stream will just
19 * count the number of bytes that would have been written. In this case
20 * max_size is not checked.
23 * 1) Return false on IO errors. This will cause encoding to abort.
25 * 2) You can use state to store your own data (e.g. buffer pointer).
27 * 3) pb_write will update bytes_written after your callback runs.
29 * 4) Substreams will modify max_size and bytes_written. Don't use them to
30 * calculate any pointers.
35 /* Callback pointer is not used in buffer-only configuration.
36 * Having an int pointer here allows binary compatibility but
37 * gives an error if someone tries to assign callback function.
38 * Also, NULL pointer marks a 'sizing stream' that does not
43 bool (*callback)(pb_ostream_t *stream, const uint8_t *buf, size_t count);
45 void *state; /* Free field for use by callback implementation */
46 size_t max_size; /* Limit number of output bytes written (or use SIZE_MAX). */
54 pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize);
55 bool pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count);
57 /* Stream type for use in computing message sizes */
59 #define PB_OSTREAM_SIZING {0,0,0,0,0}
61 #define PB_OSTREAM_SIZING {0,0,0,0}
64 /* Encode struct to given output stream.
65 * Returns true on success, false on any failure.
66 * The actual struct pointed to by src_struct must match the description in fields.
67 * All required fields in the struct are assumed to have been filled in.
69 bool pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);
71 /* --- Helper functions ---
72 * You may want to use these from your caller or callbacks.
75 /* Encode field header based on LTYPE and field number defined in the field structure.
76 * Call this from the callback before writing out field contents. */
77 bool pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field);
79 /* Encode field header by manually specifing wire type. You need to use this if
80 * you want to write out packed arrays from a callback field. */
81 bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number);
83 /* Encode an integer in the varint format.
84 * This works for bool, enum, int32, int64, uint32 and uint64 field types. */
85 bool pb_encode_varint(pb_ostream_t *stream, uint64_t value);
87 /* Encode an integer in the zig-zagged svarint format.
88 * This works for sint32 and sint64. */
89 bool pb_encode_svarint(pb_ostream_t *stream, int64_t value);
91 /* Encode a string or bytes type field. For strings, pass strlen(s) as size. */
92 bool pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size);
94 /* Encode a fixed32, sfixed32 or float value.
95 * You need to pass a pointer to a 4-byte wide C variable. */
96 bool pb_encode_fixed32(pb_ostream_t *stream, const void *value);
98 /* Encode a fixed64, sfixed64 or double value.
99 * You need to pass a pointer to a 8-byte wide C variable. */
100 bool pb_encode_fixed64(pb_ostream_t *stream, const void *value);
102 /* Encode a submessage field.
103 * You need to pass the pb_field_t array and pointer to struct, just like with pb_encode().
104 * This internally encodes the submessage twice, first to calculate message size and then to actually write it out.
106 bool pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);
108 /* --- Internal functions ---
109 * These functions are not terribly useful for the average library user, but
110 * are exported to make the unit testing and extending nanopb easier.
113 #ifdef NANOPB_INTERNALS
114 bool pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
115 bool pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
116 bool pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src);
117 bool pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src);
118 bool pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src);
119 bool pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src);
122 /* This function is not recommended for new programs. Use pb_encode_submessage()
123 * instead, it has the same functionality with a less confusing interface. */
124 bool pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src);