| /* pb_encode.h: Functions to encode protocol buffers. Depends on pb_encode.c. |
| * The main function is pb_encode. You also need an output stream, and the |
| * field descriptions created by nanopb_generator.py. |
| */ |
| |
| #ifndef PB_ENCODE_H_INCLUDED |
| #define PB_ENCODE_H_INCLUDED |
| |
| #include "pb.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* Structure for defining custom output streams. You will need to provide |
| * a callback function to write the bytes to your storage, which can be |
| * for example a file or a network socket. |
| * |
| * The callback must conform to these rules: |
| * |
| * 1) Return false on IO errors. This will cause encoding to abort. |
| * 2) You can use state to store your own data (e.g. buffer pointer). |
| * 3) pb_write will update bytes_written after your callback runs. |
| * 4) Substreams will modify max_size and bytes_written. Don't use them |
| * to calculate any pointers. |
| */ |
| struct pb_ostream_s |
| { |
| #ifdef PB_BUFFER_ONLY |
| /* Callback pointer is not used in buffer-only configuration. |
| * Having an int pointer here allows binary compatibility but |
| * gives an error if someone tries to assign callback function. |
| * Also, NULL pointer marks a 'sizing stream' that does not |
| * write anything. |
| */ |
| const int *callback; |
| #else |
| bool (*callback)(pb_ostream_t *stream, const pb_byte_t *buf, size_t count); |
| #endif |
| |
| /* state is a free field for use of the callback function defined above. |
| * Note that when pb_ostream_from_buffer() is used, it reserves this field |
| * for its own use. |
| */ |
| void *state; |
| |
| /* Limit number of output bytes written. Can be set to SIZE_MAX. */ |
| size_t max_size; |
| |
| /* Number of bytes written so far. */ |
| size_t bytes_written; |
| |
| #ifndef PB_NO_ERRMSG |
| /* Pointer to constant (ROM) string when decoding function returns error */ |
| const char *errmsg; |
| #endif |
| }; |
| |
| /*************************** |
| * Main encoding functions * |
| ***************************/ |
| |
| /* Encode a single protocol buffers message from C structure into a stream. |
| * Returns true on success, false on any failure. |
| * The actual struct pointed to by src_struct must match the description in fields. |
| * All required fields in the struct are assumed to have been filled in. |
| * |
| * Example usage: |
| * MyMessage msg = {}; |
| * uint8_t buffer[64]; |
| * pb_ostream_t stream; |
| * |
| * msg.field1 = 42; |
| * stream = pb_ostream_from_buffer(buffer, sizeof(buffer)); |
| * pb_encode(&stream, MyMessage_fields, &msg); |
| */ |
| bool pb_encode(pb_ostream_t *stream, const pb_msgdesc_t *fields, const void *src_struct); |
| |
| /* Extended version of pb_encode, with several options to control the |
| * encoding process: |
| * |
| * PB_ENCODE_DELIMITED: Prepend the length of message as a varint. |
| * Corresponds to writeDelimitedTo() in Google's |
| * protobuf API. |
| * |
| * PB_ENCODE_NULLTERMINATED: Append a null byte to the message for termination. |
| * NOTE: This behaviour is not supported in most other |
| * protobuf implementations, so PB_ENCODE_DELIMITED |
| * is a better option for compatibility. |
| */ |
| #define PB_ENCODE_DELIMITED 0x02U |
| #define PB_ENCODE_NULLTERMINATED 0x04U |
| bool pb_encode_ex(pb_ostream_t *stream, const pb_msgdesc_t *fields, const void *src_struct, unsigned int flags); |
| |
| /* Defines for backwards compatibility with code written before nanopb-0.4.0 */ |
| #define pb_encode_delimited(s,f,d) pb_encode_ex(s,f,d, PB_ENCODE_DELIMITED) |
| #define pb_encode_nullterminated(s,f,d) pb_encode_ex(s,f,d, PB_ENCODE_NULLTERMINATED) |
| |
| /* Encode the message to get the size of the encoded data, but do not store |
| * the data. */ |
| bool pb_get_encoded_size(size_t *size, const pb_msgdesc_t *fields, const void *src_struct); |
| |
| /************************************** |
| * Functions for manipulating streams * |
| **************************************/ |
| |
| /* Create an output stream for writing into a memory buffer. |
| * The number of bytes written can be found in stream.bytes_written after |
| * encoding the message. |
| * |
| * Alternatively, you can use a custom stream that writes directly to e.g. |
| * a file or a network socket. |
| */ |
| pb_ostream_t pb_ostream_from_buffer(pb_byte_t *buf, size_t bufsize); |
| |
| /* Pseudo-stream for measuring the size of a message without actually storing |
| * the encoded data. |
| * |
| * Example usage: |
| * MyMessage msg = {}; |
| * pb_ostream_t stream = PB_OSTREAM_SIZING; |
| * pb_encode(&stream, MyMessage_fields, &msg); |
| * printf("Message size is %d\n", stream.bytes_written); |
| */ |
| #ifndef PB_NO_ERRMSG |
| #define PB_OSTREAM_SIZING {0,0,0,0,0} |
| #else |
| #define PB_OSTREAM_SIZING {0,0,0,0} |
| #endif |
| |
| /* Function to write into a pb_ostream_t stream. You can use this if you need |
| * to append or prepend some custom headers to the message. |
| */ |
| bool pb_write(pb_ostream_t *stream, const pb_byte_t *buf, size_t count); |
| |
| |
| /************************************************ |
| * Helper functions for writing field callbacks * |
| ************************************************/ |
| |
| /* Encode field header based on type and field number defined in the field |
| * structure. Call this from the callback before writing out field contents. */ |
| bool pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_iter_t *field); |
| |
| /* Encode field header by manually specifying wire type. You need to use this |
| * if you want to write out packed arrays from a callback field. */ |
| bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number); |
| |
| /* Encode an integer in the varint format. |
| * This works for bool, enum, int32, int64, uint32 and uint64 field types. */ |
| #ifndef PB_WITHOUT_64BIT |
| bool pb_encode_varint(pb_ostream_t *stream, uint64_t value); |
| #else |
| bool pb_encode_varint(pb_ostream_t *stream, uint32_t value); |
| #endif |
| |
| /* Encode an integer in the zig-zagged svarint format. |
| * This works for sint32 and sint64. */ |
| #ifndef PB_WITHOUT_64BIT |
| bool pb_encode_svarint(pb_ostream_t *stream, int64_t value); |
| #else |
| bool pb_encode_svarint(pb_ostream_t *stream, int32_t value); |
| #endif |
| |
| /* Encode a string or bytes type field. For strings, pass strlen(s) as size. */ |
| bool pb_encode_string(pb_ostream_t *stream, const pb_byte_t *buffer, size_t size); |
| |
| /* Encode a fixed32, sfixed32 or float value. |
| * You need to pass a pointer to a 4-byte wide C variable. */ |
| bool pb_encode_fixed32(pb_ostream_t *stream, const void *value); |
| |
| #ifndef PB_WITHOUT_64BIT |
| /* Encode a fixed64, sfixed64 or double value. |
| * You need to pass a pointer to a 8-byte wide C variable. */ |
| bool pb_encode_fixed64(pb_ostream_t *stream, const void *value); |
| #endif |
| |
| #ifdef PB_CONVERT_DOUBLE_FLOAT |
| /* Encode a float value so that it appears like a double in the encoded |
| * message. */ |
| bool pb_encode_float_as_double(pb_ostream_t *stream, float value); |
| #endif |
| |
| /* Encode a submessage field. |
| * You need to pass the pb_field_t array and pointer to struct, just like |
| * with pb_encode(). This internally encodes the submessage twice, first to |
| * calculate message size and then to actually write it out. |
| */ |
| bool pb_encode_submessage(pb_ostream_t *stream, const pb_msgdesc_t *fields, const void *src_struct); |
| |
| #ifdef __cplusplus |
| } /* extern "C" */ |
| #endif |
| |
| #endif |