.. contents ::
+
+
+
Compilation options
===================
-The following options can be specified using -D switch given to the C compiler:
+The following options can be specified in one of two ways:
+
+1. Using the -D switch on the C compiler command line.
+2. By #defining them at the top of pb.h.
+
+You must have the same settings for the nanopb library and all code that
+includes pb.h.
+
+============================ ================================================
+PB_NO_PACKED_STRUCTS Disable packed structs. Increases RAM usage but
+ is necessary on some platforms that do not
+ support unaligned memory access.
+PB_ENABLE_MALLOC Set this to enable dynamic allocation support
+ in the decoder.
+PB_MAX_REQUIRED_FIELDS Maximum number of required fields to check for
+ presence. Default value is 64. Increases stack
+ usage 1 byte per every 8 fields. Compiler
+ warning will tell if you need this.
+PB_FIELD_16BIT Add support for tag numbers > 255 and fields
+ larger than 255 bytes or 255 array entries.
+ 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.
+PB_BUFFER_ONLY Disables the support for custom streams. Only
+ supports encoding and decoding with memory
+ buffers. Speeds up execution and decreases code
+ size slightly.
+PB_OLD_CALLBACK_STYLE Use the old function signature (void\* instead
+ of void\*\*) for callback fields. This was the
+ default until nanopb-0.2.1.
+PB_SYSTEM_HEADER Replace the standard header files with a single
+ header file. It should define all the required
+ functions and typedefs listed on the
+ `overview page`_. Value must include quotes,
+ for example *#define PB_SYSTEM_HEADER "foo.h"*.
+============================ ================================================
+
+The PB_MAX_REQUIRED_FIELDS, PB_FIELD_16BIT and PB_FIELD_32BIT settings allow
+raising some datatype limits to suit larger messages. Their need is recognized
+automatically by C-preprocessor #if-directives in the generated .pb.h files.
+The default setting is to use the smallest datatypes (least resources used).
+
+.. _`overview page`: index.html#compiler-requirements
+
+
+Proto file options
+==================
+The generator behaviour can be adjusted using these options, defined in the
+'nanopb.proto' file in the generator folder:
+
+============================ ================================================
+max_size Allocated size for *bytes* and *string* fields.
+max_count Allocated number of entries in arrays
+ (*repeated* fields).
+int_size Override the integer type of a field.
+ (To use e.g. uint8_t to save RAM.)
+type Type of the generated field. Default value
+ is *FT_DEFAULT*, which selects automatically.
+ You can use *FT_CALLBACK*, *FT_POINTER*,
+ *FT_STATIC* or *FT_IGNORE* to force a callback
+ field, a dynamically allocated field, a static
+ field or to completely ignore the field.
+long_names Prefix the enum name to the enum value in
+ definitions, i.e. *EnumName_EnumValue*. Enabled
+ by default.
+packed_struct Make the generated structures packed.
+ NOTE: This cannot be used on CPUs that break
+ on unaligned accesses to variables.
+skip_message Skip the whole message from generation.
+no_unions Generate 'oneof' fields as optional fields
+ instead of C unions.
+msgid Specifies a unique id for this message type.
+ Can be used by user code as an identifier.
+anonymous_oneof Generate 'oneof' fields as anonymous unions.
+============================ ================================================
+
+These options can be defined for the .proto files before they are converted
+using the nanopb-generatory.py. There are three ways to define the options:
+
+1. Using a separate .options file.
+ This is the preferred way as of nanopb-0.2.1, because it has the best
+ compatibility with other protobuf libraries.
+2. Defining the options on the command line of nanopb_generator.py.
+ This only makes sense for settings that apply to a whole file.
+3. Defining the options in the .proto file using the nanopb extensions.
+ This is the way used in nanopb-0.1, and will remain supported in the
+ future. It however sometimes causes trouble when using the .proto file
+ with other protobuf libraries.
+
+The effect of the options is the same no matter how they are given. The most
+common purpose is to define maximum size for string fields in order to
+statically allocate them.
+
+Defining the options in a .options file
+---------------------------------------
+The preferred way to define options is to have a separate file
+'myproto.options' in the same directory as the 'myproto.proto'. ::
+
+ # myproto.proto
+ message MyMessage {
+ required string name = 1;
+ repeated int32 ids = 4;
+ }
+
+::
+
+ # myproto.options
+ MyMessage.name max_size:40
+ MyMessage.ids max_count:5
+
+The generator will automatically search for this file and read the
+options from it. The file format is as follows:
+
+* Lines starting with '#' or '//' are regarded as comments.
+* Blank lines are ignored.
+* All other lines should start with a field name pattern, followed by one or
+ more options. For example: *"MyMessage.myfield max_size:5 max_count:10"*.
+* The field name pattern is matched against a string of form *'Message.field'*.
+ For nested messages, the string is *'Message.SubMessage.field'*.
+* The field name pattern may use the notation recognized by Python fnmatch():
+
+ - *\** matches any part of string, like 'Message.\*' for all fields
+ - *\?* matches any single character
+ - *[seq]* matches any of characters 's', 'e' and 'q'
+ - *[!seq]* matches any other character
+
+* The options are written as *'option_name:option_value'* and several options
+ can be defined on same line, separated by whitespace.
+* Options defined later in the file override the ones specified earlier, so
+ it makes sense to define wildcard options first in the file and more specific
+ ones later.
+
+If preferred, the name of the options file can be set using the command line
+switch *-f* to nanopb_generator.py.
+
+Defining the options on command line
+------------------------------------
+The nanopb_generator.py has a simple command line option *-s OPTION:VALUE*.
+The setting applies to the whole file that is being processed.
+
+Defining the options in the .proto file
+---------------------------------------
+The .proto file format allows defining custom options for the fields.
+The nanopb library comes with *nanopb.proto* which does exactly that, allowing
+you do define the options directly in the .proto file::
+
+ import "nanopb.proto";
+
+ message MyMessage {
+ required string name = 1 [(nanopb).max_size = 40];
+ repeated int32 ids = 4 [(nanopb).max_count = 5];
+ }
+
+A small complication is that you have to set the include path of protoc so that
+nanopb.proto can be found. This file, in turn, requires the file
+*google/protobuf/descriptor.proto*. This is usually installed under
+*/usr/include*. Therefore, to compile a .proto file which uses options, use a
+protoc command similar to::
+
+ protoc -I/usr/include -Inanopb/generator -I. -omessage.pb message.proto
+
+The options can be defined in file, message and field scopes::
+
+ option (nanopb_fileopt).max_size = 20; // File scope
+ message Message
+ {
+ option (nanopb_msgopt).max_size = 30; // Message scope
+ required string fieldsize = 1 [(nanopb).max_size = 40]; // Field scope
+ }
+
+
+
+
+
+
+
-================== ==============================================================================================
-__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.h
====
+pb_byte_t
+---------
+Type used for storing byte-sized data, such as raw binary input and bytes-type fields. ::
+
+ typedef uint_least8_t pb_byte_t;
+
+For most platforms this is equivalent to `uint8_t`. Some platforms however do not support
+8-bit variables, and on those platforms 16 or 32 bits need to be used for each byte.
+
pb_type_t
---------
-Defines the encoder/decoder behaviour that should be used for a field. ::
+Type used to store the type of each field, to control the encoder/decoder behaviour. ::
- typedef enum { ... } pb_type_t;
+ typedef uint_least8_t pb_type_t;
-The low-order byte of the enumeration values defines the function that can be used for encoding and decoding the field data:
+The low-order nibble of the enumeration values defines the function that can be used for encoding and decoding the field data:
==================== ===== ================================================
LTYPE identifier Value Storage format
==================== ===== ================================================
PB_LTYPE_VARINT 0x00 Integer.
PB_LTYPE_SVARINT 0x01 Integer, zigzag encoded.
-PB_LTYPE_FIXED 0x02 Integer or floating point.
-PB_LTYPE_BYTES 0x03 Structure with *size_t* field and byte array.
-PB_LTYPE_STRING 0x04 Null-terminated string.
-PB_LTYPE_SUBMESSAGE 0x05 Submessage structure.
+PB_LTYPE_FIXED32 0x02 32-bit integer or floating point.
+PB_LTYPE_FIXED64 0x03 64-bit integer or floating point.
+PB_LTYPE_BYTES 0x04 Structure with *size_t* field and byte array.
+PB_LTYPE_STRING 0x05 Null-terminated string.
+PB_LTYPE_SUBMESSAGE 0x06 Submessage structure.
==================== ===== ================================================
-The high-order byte defines whether the field is required, optional, repeated or callback:
+The bits 4-5 define whether the field is required, optional or repeated:
==================== ===== ================================================
HTYPE identifier Value Field handling
PB_HTYPE_REQUIRED 0x00 Verify that field exists in decoded message.
PB_HTYPE_OPTIONAL 0x10 Use separate *has_<field>* boolean to specify
whether the field is present.
-PB_HTYPE_ARRAY 0x20 A repeated field with preallocated array.
+ (Unless it is a callback)
+PB_HTYPE_REPEATED 0x20 A repeated field with preallocated array.
Separate *<field>_count* for number of items.
-PB_HTYPE_CALLBACK 0x30 A field with dynamic storage size, data is
- actually a pointer to a structure containing a
- callback function.
+ (Unless it is a callback)
+==================== ===== ================================================
+
+The bits 6-7 define the how the storage for the field is allocated:
+
+==================== ===== ================================================
+ATYPE identifier Value Allocation method
==================== ===== ================================================
+PB_ATYPE_STATIC 0x00 Statically allocated storage in the structure.
+PB_ATYPE_CALLBACK 0x40 A field with dynamic storage size. Struct field
+ actually contains a pointer to a callback
+ function.
+==================== ===== ================================================
+
pb_field_t
----------
Describes a single structure field with memory position in relation to others. The descriptions are usually autogenerated. ::
- typedef struct _pb_field_t pb_field_t;
- struct _pb_field_t {
- uint8_t tag;
+ typedef struct pb_field_s pb_field_t;
+ struct pb_field_s {
+ pb_size_t tag;
pb_type_t type;
- uint8_t data_offset;
- int8_t size_offset;
- uint8_t data_size;
- uint8_t array_size;
+ pb_size_t data_offset;
+ pb_ssize_t size_offset;
+ pb_size_t data_size;
+ pb_size_t array_size;
const void *ptr;
} pb_packed;
:tag: Tag number of the field or 0 to terminate a list of fields.
-:type: LTYPE and HTYPE of the field.
+:type: LTYPE, HTYPE and ATYPE of the field.
:data_offset: Offset of field data, relative to the end of the previous field.
:size_offset: Offset of *bool* flag for optional fields or *size_t* count for arrays, relative to field data.
:data_size: Size of a single data entry, in bytes. For PB_LTYPE_BYTES, the size of the byte array inside the containing structure. For PB_HTYPE_CALLBACK, size of the C data type if known.
: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_FIELD_16BIT*.
pb_bytes_array_t
----------------
An byte array with a field for storing the length::
typedef struct {
- size_t size;
- uint8_t bytes[1];
+ pb_size_t size;
+ pb_byte_t bytes[1];
} pb_bytes_array_t;
In an actual array, the length of *bytes* may be different.
typedef struct _pb_callback_t pb_callback_t;
struct _pb_callback_t {
union {
- bool (*decode)(pb_istream_t *stream, const pb_field_t *field, void *arg);
- bool (*encode)(pb_ostream_t *stream, const pb_field_t *field, const void *arg);
+ bool (*decode)(pb_istream_t *stream, const pb_field_t *field, void **arg);
+ bool (*encode)(pb_ostream_t *stream, const pb_field_t *field, void * const *arg);
} funcs;
void *arg;
};
-The *arg* is passed to the callback when calling. It can be used to store any information that the callback might need.
+A pointer to the *arg* is passed to the callback when calling. It can be used to store any information that the callback might need.
+
+Previously the function received just the value of *arg* instead of a pointer to it. This old behaviour can be enabled by defining *PB_OLD_CALLBACK_STYLE*.
When calling `pb_encode`_, *funcs.encode* is used, and similarly when calling `pb_decode`_, *funcs.decode* is used. The function pointers are stored in the same memory location but are of incompatible types. You can set the function pointer to NULL to skip the field.
PB_WT_32BIT = 5
} pb_wire_type_t;
+pb_extension_type_t
+-------------------
+Defines the handler functions and auxiliary data for a field that extends
+another message. Usually autogenerated by *nanopb_generator.py*::
+
+ typedef struct {
+ bool (*decode)(pb_istream_t *stream, pb_extension_t *extension,
+ uint32_t tag, pb_wire_type_t wire_type);
+ bool (*encode)(pb_ostream_t *stream, const pb_extension_t *extension);
+ const void *arg;
+ } pb_extension_type_t;
+
+In the normal case, the function pointers are *NULL* and the decoder and
+encoder use their internal implementations. The internal implementations
+assume that *arg* points to a *pb_field_t* that describes the field in question.
+
+To implement custom processing of unknown fields, you can provide pointers
+to your own functions. Their functionality is mostly the same as for normal
+callback fields, except that they get called for any unknown field when decoding.
+
+pb_extension_t
+--------------
+Ties together the extension field type and the storage for the field value::
+
+ typedef struct {
+ const pb_extension_type_t *type;
+ void *dest;
+ pb_extension_t *next;
+ bool found;
+ } pb_extension_t;
+
+:type: Pointer to the structure that defines the callback functions.
+:dest: Pointer to the variable that stores the field value
+ (as used by the default extension callback functions.)
+:next: Pointer to the next extension handler, or *NULL*.
+:found: Decoder sets this to true if the extension was found.
+
+PB_GET_ERROR
+------------
+Get the current error message from a stream, or a placeholder string if
+there is no error message::
+
+ #define PB_GET_ERROR(stream) (string expression)
+
+This should be used for printing errors, for example::
+
+ if (!pb_decode(...))
+ {
+ printf("Decode failed: %s\n", PB_GET_ERROR(stream));
+ }
+
+The macro only returns pointers to constant strings (in code memory),
+so that there is no need to release the returned pointer.
+
+PB_RETURN_ERROR
+---------------
+Set the error message and return false::
+
+ #define PB_RETURN_ERROR(stream,msg) (sets error and returns false)
+
+This should be used to handle error conditions inside nanopb functions
+and user callback functions::
+
+ if (error_condition)
+ {
+ PB_RETURN_ERROR(stream, "something went wrong");
+ }
+
+The *msg* parameter must be a constant string.
+
+
+
pb_encode.h
===========
----------------------
Constructs an output stream for writing into a memory buffer. This is just a helper function, it doesn't do anything you couldn't do yourself in a callback function. It uses an internal callback that stores the pointer in stream *state* field. ::
- pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize);
+ pb_ostream_t pb_ostream_from_buffer(pb_byte_t *buf, size_t bufsize);
:buf: Memory buffer to write into.
:bufsize: Maximum number of bytes to write.
--------
Writes data to an output stream. Always use this function, instead of trying to call stream callback manually. ::
- bool pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count);
+ bool pb_write(pb_ostream_t *stream, const pb_byte_t *buf, size_t count);
:stream: Output stream to write to.
:buf: Pointer to buffer with the data to be written.
Normally pb_encode simply walks through the fields description array and serializes each field in turn. However, submessages must be serialized twice: first to calculate their size and then to actually write them to output. This causes some constraints for callback fields, which must return the same data on every call.
+pb_encode_delimited
+-------------------
+Calculates the length of the message, encodes it as varint and then encodes the message. ::
+
+ bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct);
+
+(parameters are the same as for `pb_encode`_.)
+
+A common way to indicate the message length in Protocol Buffers is to prefix it with a varint.
+This function does this, and it is compatible with *parseDelimitedFrom* in Google's protobuf library.
+
.. sidebar:: Encoding fields manually
The functions with names *pb_encode_\** 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_encode`_ will call your callback function, which in turn will call *pb_encode_\** functions repeatedly to write out values.
Writing packed arrays is a little bit more involved: you need to use `pb_encode_tag` and specify `PB_WT_STRING` as the wire type. Then you need to know exactly how much data you are going to write, and use `pb_encode_varint`_ to write out the number of bytes before writing the actual data. Substreams can be used to determine the number of bytes beforehand; see `pb_encode_submessage`_ source code for an example.
+pb_get_encoded_size
+-------------------
+Calculates the length of the encoded message. ::
+
+ bool pb_get_encoded_size(size_t *size, const pb_field_t fields[], const void *src_struct);
+
+:size: Calculated size of the encoded message.
+:fields: A field description array, usually autogenerated.
+:src_struct: Pointer to the data that will be serialized.
+:returns: True on success, false on detectable errors in field description or if a field encoder returns false.
+
pb_encode_tag
-------------
Starts a field in the Protocol Buffers binary format: encodes the field number and the wire type of the data. ::
- bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, int field_number);
+ bool pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number);
:stream: Output stream to write to. 1-5 bytes will be written.
:wiretype: PB_WT_VARINT, PB_WT_64BIT, PB_WT_STRING or PB_WT_32BIT
----------------
Writes the length of a string as varint and then contents of the string. Works for fields of type `bytes` and `string`::
- bool pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size);
+ bool pb_encode_string(pb_ostream_t *stream, const pb_byte_t *buffer, size_t size);
:stream: Output stream to write to.
:buffer: Pointer to string data.
If the submessage contains callback fields, the callback function might misbehave and write out a different amount of data on the second call. This situation is recognized and *false* is returned, but garbage will be written to the output before the problem is detected.
+
+
+
+
+
+
+
+
+
+
+
pb_decode.h
===========
----------------------
Helper function for creating an input stream that reads data from a memory buffer. ::
- pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
+ pb_istream_t pb_istream_from_buffer(const pb_byte_t *buf, size_t bufsize);
:buf: Pointer to byte array to read from.
:bufsize: Size of the byte array.
-------
Read data from input stream. Always use this function, don't try to call the stream callback directly. ::
- bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
+ bool pb_read(pb_istream_t *stream, pb_byte_t *buf, size_t count);
:stream: Input stream to read from.
:buf: Buffer to store the data to, or NULL to just read data without storing it anywhere.
For optional fields, this function applies the default value and sets *has_<field>* to false if the field is not present.
-Because of memory concerns, the detection of missing required fields is not perfect if the structure contains more than 32 fields.
+If *PB_ENABLE_MALLOC* is defined, this function may allocate storage for any pointer type fields.
+In this case, you have to call `pb_release`_ to release the memory after you are done with the message.
+On error return `pb_decode` will release the memory itself.
-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`_.)
-pb_skip_varint
---------------
-Skip a varint_ encoded integer without decoding it. ::
+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.
- bool pb_skip_varint(pb_istream_t *stream);
+In addition to decoding a single message, this function can be used to merge two messages, so that
+values from previous message will remain if the new message does not contain a field.
-:stream: Input stream to read from. Will read 1 byte at a time until the MSB is clear.
-:returns: True on success, false on IO error.
+This function *will not* release the message even on error return. If you use *PB_ENABLE_MALLOC*,
+you will need to call `pb_release`_ yourself.
-pb_skip_string
---------------
-Skip a varint-length-prefixed string. This means skipping a value with wire type PB_WT_STRING. ::
+pb_decode_delimited
+-------------------
+Same as `pb_decode`_, except that it first reads a varint with the length of the message. ::
- bool pb_skip_string(pb_istream_t *stream);
+ bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
-:stream: Input stream to read from.
-:returns: True on success, false on IO error or length exceeding uint32_t.
+(parameters are the same as for `pb_decode`_.)
+
+A common method to indicate message size in Protocol Buffers is to prefix it with a varint.
+This function is compatible with *writeDelimitedTo* in the Google's Protocol Buffers library.
+
+pb_release
+----------
+Releases any dynamically allocated fields::
+
+ void pb_release(const pb_field_t fields[], void *dest_struct);
+
+:fields: A field description array. Usually autogenerated.
+:dest_struct: Pointer to structure where data is stored. If NULL, function does nothing.
+
+This function is only available if *PB_ENABLE_MALLOC* is defined. It will release any
+pointer type fields in the structure and set the pointers to NULL.
pb_decode_tag
-------------
Decode the tag that comes before field in the protobuf encoding::
- bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, int *tag, bool *eof);
+ bool pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof);
:stream: Input stream to read from.
:wire_type: Pointer to variable where to store the wire type of the field.
: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);
+ bool pb_decode_fixed64(pb_istream_t *stream, void *dest);
:stream: Input stream to read from. 8 bytes will be read.
-:field: Not used.
: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.
+Same as `pb_decode_fixed32`_, except this reads 8 bytes.
-pb_dec_bytes
-------------
-Field decoder for PB_LTYPE_BYTES. Reads a length-prefixed block of bytes. ::
-
- bool pb_dec_bytes(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 bytes fields in callbacks, use
-*stream->bytes_left* and `pb_read`_.
-
-: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. ::
-
- bool pb_dec_string(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 string 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 character array of size *field->data_size*.
-:returns: True on success, false on IO error or if length exceeds the array size.
+: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.
-This function null-terminates the string when successful. On error, the contents of the destination array is undefined.
+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.
-pb_dec_submessage
------------------
-Field decoder for PB_LTYPE_SUBMESSAGE. Calls `pb_decode`_ to perform the actual decoding. ::
+pb_close_string_substream
+-------------------------
+Close the substream created with `pb_make_string_substream`_. ::
- 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