/* 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_INCLUDED #define PB_DECODE_H_INCLUDED #include "pb.h" #ifdef __cplusplus extern "C" { #endif /* 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_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. */ int *callback; #else bool (*callback)(pb_istream_t *stream, pb_byte_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 }; /*************************** * 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. * * Note: If this function returns with an error, it will not release any * dynamically allocated fields. You will need to call pb_release() yourself. */ 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); /* Same as pb_decode_delimited, except that it does not initialize the destination structure. * See pb_decode_noinit */ bool pb_decode_delimited_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); /* Same as pb_decode, except allows the message to be terminated with a null byte. * NOTE: Until nanopb-0.4.0, pb_decode() also allows null-termination. This behaviour * is not supported in most other protobuf implementations, so pb_decode_delimited() * is a better option for compatibility. */ bool pb_decode_nullterminated(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct); #ifdef PB_ENABLE_MALLOC /* Release any allocated pointer fields. If you use dynamic allocation, you should * call this for any successfully decoded message when you are done with it. If * pb_decode() returns with an error, the message is already released. */ void pb_release(const pb_field_t fields[], void *dest_struct); #endif /************************************** * Functions for manipulating streams * **************************************/ /* 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(const pb_byte_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, pb_byte_t *buf, size_t count); /************************************************ * Helper functions for writing field callbacks * ************************************************/ /* 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 enum, int32, * int64, uint32 and uint64 field types. */ #ifndef PB_WITHOUT_64BIT bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest); #else #define pb_decode_varint pb_decode_varint32 #endif /* Decode an integer in the varint format. This works for enum, int32, * and uint32 field types. */ bool pb_decode_varint32(pb_istream_t *stream, uint32_t *dest); /* Decode a bool value in varint format. */ bool pb_decode_bool(pb_istream_t *stream, bool *dest); /* Decode an integer in the zig-zagged svarint format. This works for sint32 * and sint64. */ #ifndef PB_WITHOUT_64BIT bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest); #else bool pb_decode_svarint(pb_istream_t *stream, int32_t *dest); #endif /* 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); #ifndef PB_WITHOUT_64BIT /* 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); #endif /* 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); bool pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream); #ifdef __cplusplus } /* extern "C" */ #endif #endif