Nanopb files
Dependents: nanopb_V2 Message_generator LEX_Threaded_Programming_V3
Diff: pb_encode.h
- Revision:
- 0:c7beea49fc91
- Child:
- 2:d2c61a9be078
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/pb_encode.h Tue Feb 19 20:03:29 2013 +0000 @@ -0,0 +1,120 @@ +#ifndef _PB_ENCODE_H_ +#define _PB_ENCODE_H_ + +/* 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, structures + * and their field descriptions (just like with pb_decode). + */ + +#include <stdbool.h> +#include "pb.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* Lightweight output stream. + * You can provide callback for writing or use pb_ostream_from_buffer. + * + * Alternatively, callback can be NULL in which case the stream will just + * count the number of bytes that would have been written. In this case + * max_size is not checked. + * + * Rules for callback: + * 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_t +{ +#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. + */ + int *callback; +#else + bool (*callback)(pb_ostream_t *stream, const uint8_t *buf, size_t count); +#endif + void *state; /* Free field for use by callback implementation */ + size_t max_size; /* Limit number of output bytes written (or use SIZE_MAX). */ + size_t bytes_written; +}; + +pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize); +bool pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count); + +/* Encode struct to given output 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. + */ +bool pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct); + +/* --- Helper functions --- + * You may want to use these from your caller or callbacks. + */ + +/* Encode field header based on LTYPE 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_t *field); + +/* Encode field header by manually specifing 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. */ +bool pb_encode_varint(pb_ostream_t *stream, uint64_t value); + +/* Encode an integer in the zig-zagged svarint format. + * This works for sint32 and sint64. */ +bool pb_encode_svarint(pb_ostream_t *stream, int64_t value); + +/* Encode a string or bytes type field. For strings, pass strlen(s) as size. */ +bool pb_encode_string(pb_ostream_t *stream, const uint8_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); + +/* 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); + +/* 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_field_t fields[], const void *src_struct); + +/* --- Internal functions --- + * These functions are not terribly useful for the average library user, but + * are exported to make the unit testing and extending nanopb easier. + */ + +#ifdef NANOPB_INTERNALS +bool pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src); +bool pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src); +bool pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src); +bool pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src); +bool pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src); +bool pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src); +#endif + +/* This function is not recommended for new programs. Use pb_encode_submessage() + * instead, it has the same functionality with a less confusing interface. */ +bool pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src); + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif