Increases code size 3 bytes per each field. Compiler error will tell if you need this.
PB_FIELD_32BIT Add support for tag numbers > 65535 and fields larger than 65535 bytes or 65535 array entries.
Increases code size 9 bytes per each field. Compiler error will tell if you need this.
+PB_NO_ERRMSG Disables the support for error messages; only error information is the true/false return value.
+ Decreases the code size by a few hundred bytes.
============================ ================================================================================================
The PB_MAX_REQUIRED_FIELDS, PB_FIELD_16BIT and PB_FIELD_32BIT settings allow raising some datatype limits to suit larger messages.
For optional fields, this function applies the default value and sets *has_<field>* to false if the field is not present.
-pb_decode_varint
+pb_decode_noinit
----------------
-Read and decode a varint_ encoded integer. ::
+Same as `pb_decode`_, except does not apply the default values to fields. ::
- bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
+ bool pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
-:stream: Input stream to read from. 1-10 bytes will be read.
-:dest: Storage for the decoded integer. Value is undefined on error.
-:returns: True on success, false if value exceeds uint64_t range or an IO error happens.
+(parameters are the same as for `pb_decode`_.)
+
+The destination structure should be filled with zeros before calling this function. Doing a *memset* manually can be slightly faster than using `pb_decode`_ if you don't need any default values.
pb_skip_varint
--------------
:wire_type: Type of field to skip.
:returns: True on success, false on IO error.
-.. sidebar:: Field decoders
+.. sidebar:: Decoding fields manually
- The functions with names beginning with *pb_dec_* are called field decoders. Each PB_LTYPE has an own field decoder, which handles translating from Protocol Buffers data to C data.
+ The functions with names beginning with *pb_decode_* are used when dealing with callback fields. The typical reason for using callbacks is to have an array of unlimited size. In that case, `pb_decode`_ will call your callback function repeatedly, which can then store the values into e.g. filesystem in the order received in.
- Each field decoder reads and decodes a single value. For arrays, the decoder is called repeatedly.
+ For decoding numeric (including enumerated and boolean) values, use `pb_decode_varint`_, `pb_decode_svarint`_, `pb_decode_fixed32`_ and `pb_decode_fixed64`_. They take a pointer to a 32- or 64-bit C variable, which you may then cast to smaller datatype for storage.
- You can use the decoders from your callbacks. Just be aware that the pb_field_t passed to the callback is not directly compatible
- with the *varint* field decoders. Instead, you must create a new pb_field_t structure and set the data_size according to the data type
- you pass to *dest*, e.g. *field.data_size = sizeof(int);*. Other fields in the *pb_field_t* don't matter.
+ For decoding strings and bytes fields, the length has already been decoded. You can therefore check the total length in *stream->bytes_left* and read the data using `pb_read`_.
- The field decoder interface is a bit messy as a result of the interface required inside the nanopb library.
- Eventually they may be replaced by separate wrapper functions with a more friendly interface.
+ Finally, for decoding submessages in a callback, simply use `pb_decode`_ and pass it the *SubMessage_fields* descriptor array.
-pb_dec_varint
--------------
-Field decoder for PB_LTYPE_VARINT. ::
+pb_decode_varint
+----------------
+Read and decode a varint_ encoded integer. ::
- bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
+ bool pb_decode_varint(pb_istream_t *stream, uint64_t *dest);
:stream: Input stream to read from. 1-10 bytes will be read.
-:field: Field description structure. Only *field->data_size* matters.
-:dest: Pointer to destination integer. Must have size of *field->data_size* bytes.
-:returns: True on success, false on IO errors or if `pb_decode_varint`_ fails.
-
-This function first calls `pb_decode_varint`_. It then copies the first bytes of the 64-bit result value to *dest*, or on big endian architectures, the last bytes.
+:dest: Storage for the decoded integer. Value is undefined on error.
+:returns: True on success, false if value exceeds uint64_t range or an IO error happens.
-pb_dec_svarint
---------------
-Field decoder for PB_LTYPE_SVARINT. Similar to `pb_dec_varint`_, except that it performs zigzag-decoding on the value. ::
+pb_decode_svarint
+-----------------
+Similar to `pb_decode_varint`_, except that it performs zigzag-decoding on the value. This corresponds to the Protocol Buffers *sint32* and *sint64* datatypes. ::
- bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
+ bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest);
-(parameters are the same as `pb_dec_varint`_)
+(parameters are the same as `pb_decode_varint`_)
-pb_dec_fixed32
---------------
-Field decoder for PB_LTYPE_FIXED32. ::
+pb_decode_fixed32
+-----------------
+Decode a *fixed32*, *sfixed32* or *float* value. ::
- bool pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
+ bool pb_decode_fixed32(pb_istream_t *stream, void *dest);
:stream: Input stream to read from. 4 bytes will be read.
-:field: Not used.
:dest: Pointer to destination *int32_t*, *uint32_t* or *float*.
:returns: True on success, false on IO errors.
On big endian architectures, it then reverses the order of the bytes.
Finally, it writes the bytes to *dest*.
-pb_dec_fixed64
---------------
-Field decoder for PB_LTYPE_FIXED64. ::
+pb_decode_fixed64
+-----------------
+Decode a *fixed64*, *sfixed64* or *double* value. ::
bool pb_dec_fixed(pb_istream_t *stream, const pb_field_t *field, void *dest);
:dest: Pointer to destination *int64_t*, *uint64_t* or *double*.
:returns: True on success, false on IO errors.
-Same as `pb_dec_fixed32`_, except this reads 8 bytes.
-
-pb_dec_bytes
-------------
-Field decoder for PB_LTYPE_BYTES. Reads a length-prefixed block of bytes. ::
+Same as `pb_decode_fixed32`_, except this reads 8 bytes.
- bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
+pb_make_string_substream
+------------------------
+Decode the length for a field with wire type *PB_WT_STRING* and create a substream for reading the data. ::
-**Note:** This is an internal function that is not useful in decoder callbacks. To read bytes fields in callbacks, use
-*stream->bytes_left* and `pb_read`_.
+ bool pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream);
-:stream: Input stream to read from.
-:field: Field description structure. Only *field->data_size* matters.
-:dest: Pointer to a structure similar to pb_bytes_array_t.
-:returns: True on success, false on IO error or if length exceeds the array size.
-
-This function expects a pointer to a structure with a *size_t* field at start, and a variable sized byte array after it. It will deduce the maximum size of the array from *field->data_size*.
-
-pb_dec_string
--------------
-Field decoder for PB_LTYPE_STRING. Reads a length-prefixed string. ::
+:stream: Original input stream to read the length and data from.
+:substream: New substream that has limited length. Filled in by the function.
+:returns: True on success, false if reading the length fails.
- bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
+This function uses `pb_decode_varint`_ to read an integer from the stream. This is interpreted as a number of bytes, and the substream is set up so that its `bytes_left` is initially the same as the length, and its callback function and state the same as the parent stream.
-**Note:** This is an internal function that is not useful in decoder callbacks. To read string fields in callbacks, use
-*stream->bytes_left* and `pb_read`_.
+pb_close_string_substream
+-------------------------
+Close the substream created with `pb_make_string_substream`_. ::
-:stream: Input stream to read from.
-:field: Field description structure. Only *field->data_size* matters.
-:dest: Pointer to a character array of size *field->data_size*.
-:returns: True on success, false on IO error or if length exceeds the array size.
-
-This function null-terminates the string when successful. On error, the contents of the destination array is undefined.
-
-pb_dec_submessage
------------------
-Field decoder for PB_LTYPE_SUBMESSAGE. Calls `pb_decode`_ to perform the actual decoding. ::
-
- bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
-
-**Note:** This is an internal function that is not useful in decoder callbacks. To read submessage fields in callbacks, use
-`pb_decode`_ directly.
-
-:stream: Input stream to read from.
-:field: Field description structure. Only *field->ptr* matters.
-:dest: Pointer to the destination structure.
-:returns: True on success, false on IO error or if `pb_decode`_ fails.
+ void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream);
-The *field->ptr* should be a pointer to *pb_field_t* array describing the submessage.
+:stream: Original input stream to read the length and data from.
+:substream: Substream to close
+This function copies back the state from the substream to the parent stream.
+It must be called after done with the substream.
Code Review / apps / agl-service-can-low-level.git / blobdiff