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/* 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, and the

 * field descriptions created by nanopb_generator.py.

 */

#ifndef PB_ENCODE_H_INCLUDED

#define PB_ENCODE_H_INCLUDED

#include "pb.h"

#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:

 *

 * 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_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 pb_byte_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; /* Number of bytes written so far. */

#ifndef PB_NO_ERRMSG

    const char *errmsg;

#endif

};

/***************************

 * Main encoding functions *

 ***************************/

/* 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);

/* 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);

/* Same as pb_encode, but appends a null byte to the message for termination.

 * NOTE: This behaviour is not supported in most other protobuf implementations, so pb_encode_delimited()

 * is a better option for compatibility.

 */

bool pb_encode_nullterminated(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);

/* 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(pb_byte_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 pb_byte_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);

/* Encode field header by manually specifying 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. */

#ifndef PB_WITHOUT_64BIT

bool pb_encode_varint(pb_ostream_t *stream, uint64_t value);

#else

bool pb_encode_varint(pb_ostream_t *stream, uint32_t value);

#endif

/* Encode an integer in the zig-zagged svarint format.

 * This works for sint32 and sint64. */

#ifndef PB_WITHOUT_64BIT

bool pb_encode_svarint(pb_ostream_t *stream, int64_t value);

#else

bool pb_encode_svarint(pb_ostream_t *stream, int32_t value);

#endif

/* Encode a string or bytes type field. For strings, pass strlen(s) as size. */

bool pb_encode_string(pb_ostream_t *stream, const pb_byte_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);

#ifndef PB_WITHOUT_64BIT

/* 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);

#endif

/* 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);

#ifdef __cplusplus

} /* extern "C" */

#endif

#endif