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msgpack

MessagePack v5 for LuaJIT


local mp = require'msgpack'

MessagePack v5 decoder and encoder for LuaJIT.

mp.new([mp]) -> mp create a new mp instance (optional)
Decoding
mp:decode_next(p, [n], [i]) -> next_i, v decode value at offset i in p
mp:decode_each(p, [n], [i]) -> iter() -> next_i, v decode all values up to n bytes
Encoding
mp:encoding_buffer([min_size]) -> b create a buffer for encoding
b:encode(v) -> b encode a value (see below)
b:encode_array(t, [n]) -> b encode an array
b:encode_map(t, [pairs]) -> b encode a map
b:encode_int(x) -> b encode a number as integer
b:encode_float(x) -> b encode a float
b:encode_double(x) -> b encode a double
b:encode_bin(v, [n]) -> b encode a byte array
b:encode_ext(type, [n]) -> b encode the header for an ext value
b:encode_ext_int(ctype, x) -> b encode a raw integer (see code)
b:encode_timestamp(ts) -> b encode a timestamp value
b:size() -> n get the buffer content size
b:get() -> p, n get the buffer and its size
b:tostring() -> s get the buffer as a string
b:reset() -> b reset the buffer for reuse
mp.array(...) -> t create an encodable array from args
mp.toarray(t, [n]) -> t add mp.N to table t
Customization
mp.nil_key value to decode nil keys to (skip)
mp.nan_key value to decode NaN keys to (skip)
mp.nil_element value to decode nil array elements to (nil)
mp.decode_i64 int64_t decoder (tonumber)
mp.decode_u64 uint64_t decoder (tonumber)
mp.decoder[type] = f(mp, p, i, len) -> next_i, v add a decoder for an ext type
mp:decode_unknown(mp, p, i, len, type_code) end decode an unknown ext type
mp:isarray(t) decide if t is an array or map
mp.N key for array element count
mp.error(err) custom error constructor

Decoding behavior:

  • nil and NaN table keys are skipped, unless mp.nil_key / mp.nan_key is set.
  • nil array elements create Lua sparse arrays, unless mp.nil_element is set.
  • extension types are decoded with mp.decoder[type], falling back to mp:decode_unknown() (pre-defined as a stub that returns nil).
  • decoding errors are raised with mp.error() which defaults to error (see errors for why you’d want to replace this).
  • there’s no way to tell an empty array from an empty map.

Encoding behavior:

  • Lua numbers are packed as either integers (the smallest possible) or doubles.
  • 64bit cdata numbers are packed as 64bit integers.
  • Lua tables are encoded as arrays or maps based on mp:isarray() which by default returns true only if there’s a mp.N key present in the table. Use mp.array() to make a Lua table that will be encoded as an array or call b:encode_array() on any table.
  • you can set [mp.N] = true in the array to mean that the element count is #t.

Last updated: 40 days ago | Edit on GitHub

Package:msgpack
Pkg type:Lua+ffi
Version: 43c28d8
Last commit:
Author: Cosmin Apreutesei
License: Public Domain

Requires: glue  luajit 

Required by: sqlpp  tarantool  webb  x-widgets 


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