MessagePack for MATLAB - MEX bindings for msgpack-c supporting the modern MessagePack standard

Forked from msgpack-matlab by yida.

Purpose

To provide a MEX interface to the msgpack-c library (https://github.com/msgpack/msgpack-c) that supports the modern MessagePack specification.

yida/msgpack-matlab provided an excellent foundation for this project, but was lacking in the following areas:

• Only supported legacy MessagePack (see msgpack/msgpack/spec-old.md) (no BIN or EXT types, non-unicode RAW/STR)
• Raw/String support did not handle non-ascii bytes well.

MEX bindings for msgpack-c (https://github.com/msgpack/msgpack-c)

Requires:

• msgpack-c development library > 1.1.0 (for unpacking FLOAT32 to single need msgpack-c > 2.1.0)

install:

mex -O msgpack.cc -lmsgpack

API

Packer:

>> msg = msgpack('pack', var1, var2, ...)

Unpacker:

>> obj = msgpack('unpack', msg) 

return numericArray or charArray or LogicalArray if data are numeric otherwise return Cell or Struct

Streaming unpacker:

>> objs = msgpack('unpacker', msg)

return Cell containing numericArray, charArray, Cell or Struct

Packing EXT type

A 1x3 cell array {'MSGPACK_EXT', <ext_code>, <data_bytes_uint8>} will be packed as EXT type.

Flags

Flags may be set that affect this and future calls of msgpack() as follows:

>> msgpack('<cmd> [<flag>[ <flag>[ ...]]]', ...)

...where <cmd> may be simply set_flags or one of the other commands followed by that command's arguments, and where each <flag> is one of the following, prefixed with + to set or - to unset:

• +unicode_strs or -unicode_strs (default is set)
  • Set - MessagePack strings are assumed to be UTF-8 and are unpacked to MATLAB's UTF-16, and vis-versa
  • Unset - MessagePack strings are of unknown encoding and are unpacked as a uint8 array. When packing a char array, just try to pack MATLAB mxChars if they are smaller than 0x00ff into the MessagePack string field.
• +pack_u8_bin or -pack_u8_bin (default is unset)
  • Set - MATLAB uint8 arrays are packed into MessagePack bin messages.
  • Unset - MATLAB uint8 arrays are packed into MessagePack arrays.
  • In both cases, non-uint8 arrays are packed into MessagePack arrays. Use MATLAB's typecast to convert to uint8 to pack other types as MessagePack bin messages.
• +unpack_narrow or -unpack_narrow (default is unset)
  • Set - When unpacking scalar numeric types, unpack to the narrowest type possible.
    • Positive integers -> smallest possible uint
    • Negative integers -> smallest possible int
    • Float32 -> single
    • Float64 -> double
  • Unset - Unpack all scalar numeric types to MATLAB double type.
  • In both cases, arrays of all the same numeric type are converted as follows:
    • Positive integers -> uint64
    • Negative integers -> int64
    • Float32 -> single
    • Float64 -> double
• +unpack_map_as_cells or -unpack_map_as_cells (default is unset)
  • Set - When unpacking a map, always unpack as a 2xN cell matrix of keys and values.
  • Unset - If all keys are strings, unpack a map to a struct. If not, generate a warning and unpack to a cell matrix as above.
• +unpack_ext_w_tag or -unpack_ext_w_tag (default is unset)
  • Set - When unpacking an ext type, unpack to 1x3 cell matrix of {'MSGPACK_EXT', <ext_code>, <data_byytes_uint8>}
  • Unset - When unpacking an ext type, unpack to 1x2 cell matrix of {<ext_code>, <data>}
• +pack_other_as_nil or -pack_other_as_nil (default is unset)
  • Set - If trying to pack a type for which there is no packer function, show a warning and pack NIL instead.
  • Unset - If trying to pack a type for which there is no packer function, throw an error.
• +unpack_nil_zero, +unpack_nil_NaN, +unpack_nil_empty, +unpack_nil_cell (Default is unpack_nil_zero)
  • Rather than set and unset, there are multiple options for how to unpack NIL type.
  • zero - Unpack to zero, (or false in logical arrays). Double if scalar, uint8 if all-nil array.
  • NaN - Unpack to NaN. In otherwise integer or logical array forces a cell array.
  • empty - Unpack to empty double array. In an array forces a cell array.
  • cell - Unpack to empty cell array. In an array forces the array to a cell array.
• +unpack_nil_array_skip or -unpack_nil_skip (default is unset)
  • Set - If a nil is in an otherwise numeric or logical array, skip the nil. If all-nils, return an empty array.
  • Unset - Unpack nil as in unpack_nil_... above.

To reset flags to defaults:

msgpack('reset_flags');

To see the currently set flags

msgpack('print_flags');