X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=pb_decode.h;h=35de0a2264318984304938494f217296e05fcfa7;hb=5442e690f65fd09e7a44437da02fb7e14af6fe8f;hp=ac4d1f7014c65e7f496ef1a5a57972056d484848;hpb=ead3b734d8f96837ea6564b694df5618134e3cf8;p=apps%2Fagl-service-can-low-level.git diff --git a/pb_decode.h b/pb_decode.h index ac4d1f70..35de0a22 100644 --- a/pb_decode.h +++ b/pb_decode.h @@ -1,71 +1,122 @@ #ifndef _PB_DECODE_H_ #define _PB_DECODE_H_ +/* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c. + * The main function is pb_decode. You will also need to create an input + * stream, which is easiest to do with pb_istream_from_buffer(). + * + * You also need structures and their corresponding pb_field_t descriptions. + * These are usually generated from .proto-files with a script. + */ + #include #include "pb.h" +#ifdef __cplusplus +extern "C" { +#endif + /* Lightweight input stream. - * If buf is NULL, read but don't store bytes. - * You can to provide a callback function for reading or use + * You can provide a callback function for reading or use * pb_istream_from_buffer. * - * You can use state to store your own data (e.g. buffer pointer), + * Rules for callback: + * 1) Return false on IO errors. This will cause decoding to abort. + * + * 2) You can use state to store your own data (e.g. buffer pointer), * and rely on pb_read to verify that no-body reads past bytes_left. - * However, substreams may change bytes_left so don't use that to - * compute any pointers. + * + * 3) Your callback may be used with substreams, in which case bytes_left + * is different than from the main stream. Don't use bytes_left to compute + * any pointers. */ struct _pb_istream_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. + */ + int *callback; +#else bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count); +#endif + void *state; /* Free field for use by callback implementation */ size_t bytes_left; + +#ifndef PB_NO_ERRMSG + const char *errmsg; +#endif }; pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize); bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count); /* Decode from stream to destination struct. + * Returns true on success, false on any failure. * The actual struct pointed to by dest must match the description in fields. */ bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); +/* Same as pb_decode, except does not initialize the destination structure + * to default values. This is slightly faster if you need no default values + * and just do memset(struct, 0, sizeof(struct)) yourself. + */ +bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); + /* --- Helper functions --- * You may want to use these from your caller or callbacks. */ -bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest); -bool pb_decode_varint64(pb_istream_t *stream, uint64_t *dest); +/* Decode the tag for the next field in the stream. Gives the wire type and + * field tag. At end of the message, returns false and sets eof to true. */ +bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof); -bool pb_skip_varint(pb_istream_t *stream); -bool pb_skip_string(pb_istream_t *stream); +/* Skip the field payload data, given the wire type. */ +bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type); -/* --- Field decoders --- - * Each decoder takes stream and field description, and a pointer to the field - * in the destination struct (dest = struct_addr + field->data_offset). - * For arrays, these functions are called repeatedly. - */ +/* Decode an integer in the varint format. This works for bool, enum, int32, + * int64, uint32 and uint64 field types. */ +bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest); -bool pb_dec_uint32(pb_istream_t *stream, const pb_field_t *field, uint32_t *dest); -bool pb_dec_sint32(pb_istream_t *stream, const pb_field_t *field, int32_t *dest); -bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, uint32_t *dest); -bool pb_dec_uint64(pb_istream_t *stream, const pb_field_t *field, uint64_t *dest); -bool pb_dec_sint64(pb_istream_t *stream, const pb_field_t *field, int64_t *dest); -bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, uint64_t *dest); -bool pb_dec_bool(pb_istream_t *stream, const pb_field_t *field, bool *dest); -bool pb_dec_enum(pb_istream_t *stream, const pb_field_t *field, void *dest); +/* Decode an integer in the zig-zagged svarint format. This works for sint32 + * and sint64. */ +bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest); -bool pb_dec_float(pb_istream_t *stream, const pb_field_t *field, float *dest); -bool pb_dec_double(pb_istream_t *stream, const pb_field_t *field, double *dest); +/* Decode a fixed32, sfixed32 or float value. You need to pass a pointer to + * a 4-byte wide C variable. */ +bool pb_decode_fixed32(pb_istream_t *stream, void *dest); -bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, uint8_t *dest); -bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, uint8_t *dest); -bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest); +/* Decode a fixed64, sfixed64 or double value. You need to pass a pointer to + * a 8-byte wide C variable. */ +bool pb_decode_fixed64(pb_istream_t *stream, void *dest); -typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest); +/* Make a limited-length substream for reading a PB_WT_STRING field. */ +bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream); +void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream); -/* --- Function pointers to field decoders --- - * Order in the array must match pb_action_t LTYPE numbering. +/* --- 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. */ -const pb_decoder_t PB_DECODERS[16]; + +#ifdef NANOPB_INTERNALS +bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest); +bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest); +bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest); +bool pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest); + +bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest); +bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest); +bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest); + +bool pb_skip_varint(pb_istream_t *stream); +bool pb_skip_string(pb_istream_t *stream); +#endif + +#ifdef __cplusplus +} /* extern "C" */ +#endif #endif