.. contents ::
+Compilation options
+===================
+The following options can be specified using -D switch given to the C compiler:
+
+============================ ==============================================================================================
+__BIG_ENDIAN__ Set this if your platform stores integers and floats in big-endian format.
+ Mixed-endian systems (different layout for ints and floats) are currently not supported.
+NANOPB_INTERNALS Set this to expose the field encoder functions that are hidden since nanopb-0.1.3.
+PB_MAX_REQUIRED_FIELDS Maximum number of required fields to check for presence. Default value is 64.
+PB_MANY_FIELDS Add support for tag numbers > 255 and fields larger than 255 bytes or 255 array entries.
+ Increases code size 9 bytes per each field. Compiler error will tell if you need this.
+============================ ==============================================================================================
+
pb.h
====
:array_size: Maximum number of entries in an array, if it is an array type.
:ptr: Pointer to default value for optional fields, or to submessage description for PB_LTYPE_SUBMESSAGE.
-The *uint8_t* datatypes limit the maximum size of a single item to 255 bytes and arrays to 255 items. Compiler will warn "Initializer too large for type" if the limits are exceeded. The types can be changed to larger ones if necessary.
+The *uint8_t* datatypes limit the maximum size of a single item to 255 bytes and arrays to 255 items. Compiler will give error if the values are too large. The types can be changed to larger ones by defining *PB_MANY_FIELDS*.
pb_bytes_array_t
----------------
End of file is signalled by *stream->bytes_left* being zero after pb_read returns false.
+pb_decode
+---------
+Read and decode all fields of a structure. Reads until EOF on input stream. ::
+
+ bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
+
+:stream: Input stream to read from.
+:fields: A field description array. Usually autogenerated.
+:dest_struct: Pointer to structure where data will be stored.
+:returns: True on success, false on IO error, on detectable errors in field description, if a field encoder returns false or if a required field is missing.
+
+In Protocol Buffers binary format, EOF is only allowed between fields. If it happens anywhere else, pb_decode will return *false*. If pb_decode returns false, you cannot trust any of the data in the structure.
+
+In addition to EOF, the pb_decode implementation supports terminating a message with a 0 byte. This is compatible with the official Protocol Buffers because 0 is never a valid field tag.
+
+For optional fields, this function applies the default value and sets *has_<field>* to false if the field is not present.
+
pb_decode_varint
----------------
Read and decode a varint_ encoded integer. ::
:stream: Input stream to read from.
:returns: True on success, false on IO error or length exceeding uint32_t.
-pb_decode
----------
-Read and decode all fields of a structure. Reads until EOF on input stream. ::
+pb_decode_tag
+-------------
+Decode the tag that comes before field in the protobuf encoding::
- bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
+ bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, int *tag, bool *eof);
:stream: Input stream to read from.
-:fields: A field description array. Usually autogenerated.
-:dest_struct: Pointer to structure where data will be stored.
-:returns: True on success, false on IO error, on detectable errors in field description, if a field encoder returns false or if a required field is missing.
+:wire_type: Pointer to variable where to store the wire type of the field.
+:tag: Pointer to variable where to store the tag of the field.
+:eof: Pointer to variable where to store end-of-file status.
+:returns: True on success, false on error or EOF.
-In Protocol Buffers binary format, EOF is only allowed between fields. If it happens anywhere else, pb_decode will return *false*. If pb_decode returns false, you cannot trust any of the data in the structure.
+When the message (stream) ends, this function will return false and set *eof* to true. On other
+errors, *eof* will be set to false.
-In addition to EOF, the pb_decode implementation supports terminating a message with a 0 byte. This is compatible with the official Protocol Buffers because 0 is never a valid field tag.
+pb_skip_field
+-------------
+Remove the data for a field from the stream, without actually decoding it::
-For optional fields, this function applies the default value and sets *has_<field>* to false if the field is not present.
+ bool pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type);
-Because of memory concerns, the detection of missing required fields is not perfect if the structure contains more than 32 fields.
+:stream: Input stream to read from.
+:wire_type: Type of field to skip.
+:returns: True on success, false on IO error.
.. sidebar:: Field decoders
Code Review / apps / agl-service-can-low-level.git / blobdiff