150 lines
5.4 KiB
C
150 lines
5.4 KiB
C
/* 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, uint8_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);
|
|
|
|
#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(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 *
|
|
************************************************/
|
|
|
|
/* 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);
|
|
|
|
#ifdef __cplusplus
|
|
} /* extern "C" */
|
|
#endif
|
|
|
|
#endif
|