X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=pb_decode.h;h=98a64cc0baf9895767622a098a68bf4741f30830;hb=696a01bf140e91661eae77663de99c78c95dcc73;hp=b71e20b118231e9db1b1ee18528236ec536c0d19;hpb=14bbe229974b516a82594ec6476488154e8957fa;p=apps%2Fagl-service-can-low-level.git diff --git a/pb_decode.h b/pb_decode.h index b71e20b1..98a64cc0 100644 --- a/pb_decode.h +++ b/pb_decode.h @@ -1,55 +1,157 @@ +/* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c. + * The main function is pb_decode. You also need an input stream, and the + * field descriptions created by nanopb_generator.py. + */ + #ifndef _PB_DECODE_H_ #define _PB_DECODE_H_ -#include #include "pb.h" -// Decode from stream to destination struct. -// 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); +#ifdef __cplusplus +extern "C" { +#endif -/* --- Helper functions --- - * You may want to use these from your callbacks. +/* Structure for defining custom input streams. You will need to provide + * a callback function to read the bytes from 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 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. + * 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 -bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest); -bool pb_decode_varint64(pb_istream_t *stream, uint64_t *dest); + void *state; /* Free field for use by callback implementation */ + size_t bytes_left; + +#ifndef PB_NO_ERRMSG + const char *errmsg; +#endif +}; -bool pb_skip_varint(pb_istream_t *stream); -bool pb_skip_string(pb_istream_t *stream); +/*************************** + * Main decoding functions * + ***************************/ + +/* Decode a single protocol buffers message from input stream into a C structure. + * Returns true on success, false on any failure. + * The actual struct pointed to by dest must match the description in fields. + * Callback fields of the destination structure must be initialized by caller. + * All other fields will be initialized by this function. + * + * Example usage: + * MyMessage msg = {}; + * uint8_t buffer[64]; + * pb_istream_t stream; + * + * // ... read some data into buffer ... + * + * stream = pb_istream_from_buffer(buffer, count); + * pb_decode(&stream, MyMessage_fields, &msg); + */ +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. + * + * This can also be used for 'merging' two messages, i.e. update only the + * fields that exist in the new message. + */ +bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); + +/* Same as pb_decode, except expects the stream to start with the message size + * encoded as varint. Corresponds to parseDelimitedFrom() in Google's + * protobuf API. + */ +bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); + + +/************************************** + * Functions for manipulating streams * + **************************************/ -/* --- Field decoders --- - * Each decoder takes stream and field description, and a pointer to the field - * in the destination struct (dest = struct_addr + field->offset). +/* Create an input stream for reading from a memory buffer. + * + * Alternatively, you can use a custom stream that reads directly from e.g. + * a file or a network socket. */ +pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize); + +/* Function to read from a pb_istream_t. You can use this if you need to + * read some custom header data, or to read data in field callbacks. + */ +bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count); + + +/************************************************ + * Helper functions for writing field callbacks * + ************************************************/ -// Integer types. -bool pb_dec_uint32(pb_istream_t *stream, const pb_field_t *field, void *dest); -bool pb_dec_sint32(pb_istream_t *stream, const pb_field_t *field, void *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); + +/* Skip the field payload data, given the wire type. */ +bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type); + +/* 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); + +/* 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); + +/* 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); + +/* 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); + +/* 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); + + +/******************************* + * Internal / legacy functions * + *******************************/ + +#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_uint64(pb_istream_t *stream, const pb_field_t *field, void *dest); -bool pb_dec_sint64(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_bool(pb_istream_t *stream, const pb_field_t *field, void *dest); -// Floating point types. Info is ignored. -bool pb_dec_float(pb_istream_t *stream, const pb_field_t *field, void *dest); -bool pb_dec_double(pb_istream_t *stream, const pb_field_t *field, void *dest); - -// Byte array. Dest is pointer to bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest); - -// Null-terminated string. bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest); - -// Use callback. Dest is pointer to pb_callback_t struct. bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest); -typedef bool (*pb_decoder_t)(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 -/* --- Function pointers to field decoders --- - * Order in the array must match pb_action_t numbering. - */ -const pb_decoder_t PB_DECODERS[PB_LAST_ACT]; +#ifdef __cplusplus +} /* extern "C" */ +#endif #endif