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/* 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