X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=pb_encode.h;h=e992c8dca18a1a0dad29ad1b6450f95e83ceb501;hb=1f86b707e3a845f2c403e77173d0859dbf6aa4b0;hp=b341602d24bb0ed9313f0c0a3f4d617d1d602261;hpb=6dfba365b00175eae7e8b83aaf5d29ce190fd9eb;p=apps%2Fagl-service-can-low-level.git diff --git a/pb_encode.h b/pb_encode.h index b341602d..e992c8dc 100644 --- a/pb_encode.h +++ b/pb_encode.h @@ -1,71 +1,154 @@ -#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). + * The main function is pb_encode. You also need an output stream, and the + * field descriptions created by nanopb_generator.py. */ -#include +#ifndef PB_ENCODE_H_INCLUDED +#define PB_ENCODE_H_INCLUDED + #include "pb.h" -/* 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. +#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: * - * 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. + * 4) Substreams will modify max_size and bytes_written. Don't use them + * to calculate any pointers. */ -struct _pb_ostream_t +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. + */ + int *callback; +#else bool (*callback)(pb_ostream_t *stream, const uint8_t *buf, size_t count); - 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; +#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; /* Number of bytes written so far. */ + +#ifndef PB_NO_ERRMSG + const char *errmsg; +#endif }; -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); +/*************************** + * Main encoding functions * + ***************************/ -/* Encode struct to given output stream. +/* 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_field_t fields[], const void *src_struct); -/* --- Helper functions --- - * You may want to use these from your caller or callbacks. +/* Same as pb_encode, but prepends the length of the message as a varint. + * Corresponds to writeDelimitedTo() in Google's protobuf API. */ +bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct); -bool pb_encode_varint(pb_ostream_t *stream, uint64_t value); -bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, int field_number); -/* Encode tag based on LTYPE and field number defined in the field structure. */ +/* 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_field_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(uint8_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 uint8_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_t *field); -/* Write length as varint and then the contents of buffer. */ + +/* 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); -/* --- Field encoders --- - * Each encoder writes the content for the field. - * The tag/wire type has been written already. - */ +/* 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); -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_fixed(pb_ostream_t *stream, const pb_field_t *field, const void *src); +/* 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); -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); -bool pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src); +#ifdef __cplusplus +} /* extern "C" */ +#endif -#endif \ No newline at end of file +#endif