mp.utils — 43 functions

Hex ↔ bytes

Function	Returns	Description
hex_to_bytes(hex)	table	"4865" → {0x48, 0x65}
bytes_to_hex(bytes)	string	{0x48, 0x65} → "4865"
bytes_to_string(bytes)	string	Byte array → raw string
string_to_bytes(s)	table	Raw string → byte array
is_ascii(bytes)	bool	All bytes are printable ASCII (0x20..0x7E)
is_printable(bytes)	bool	Printable + \t \n \r
byte_to_hex(b)	string	"AB" (2 chars)
word_to_hex(w)	string	"ABCD" (4 chars)
dword_to_hex(d)	string	"DEADBEEF" (8 chars)
hex_to_int(hex)	number	Parse hex string (up to 64-bit)

Byte order

Function	Returns	Description
swap16(v)	int	Endian swap 16-bit
swap32(v)	number	Endian swap 32-bit
le16(lo, hi)	int	Assemble little-endian 16-bit
be16(hi, lo)	int	Assemble big-endian 16-bit
le32(b0, b1, b2, b3)	number	Assemble LE 32-bit (b0 = LSB)
be32(b0, b1, b2, b3)	number	Assemble BE 32-bit (b0 = MSB)

Bit operations (beyond Lua 5.5 native)

Function	Returns	Description
bit_set(v, bit)	int	Set bit
bit_clear(v, bit)	int	Clear bit
bit_test(v, bit)	bool	Test bit
bit_toggle(v, bit)	int	Toggle bit
extract_bits(v, startBit, count)	int	Extract bit field

Time

Function	Returns	Description
timer()	table	{elapsed_ms(), elapsed_s(), restart()}
timestamp()	number	ms since Unix epoch
datetime()	string	"yyyy-MM-dd HH:mm:ss"
date()	string	"yyyy-MM-dd"
time()	string	"HH:mm:ss"

JSON

Function	Returns	Description
json_parse(s)	table | nil	Parse JSON object/array; nil on error
json_encode(obj)	string	Indented JSON. Empty Lua tables encode as [] (JSON array). To force an empty JSON OBJECT, pass {__json_object = true}
json_encode_compact(obj)	string	Single-line JSON, same accepted types and same empty-table semantics

String helpers

Function	Returns	Description
trim(s)	string	Strip leading/trailing whitespace
split(s, sep)	table	Split into parts
starts_with(s, prefix)	bool	—
ends_with(s, suffix)	bool	—
contains(s, sub)	bool	—
to_upper(s)	string	—
to_lower(s)	string	—
replace(s, from, to)	string	Replace all occurrences

Table helpers

Function	Returns	Description
table_keys(t)	table	Array of keys
table_values(t)	table	Array of values
table_size(t)	int	Total entries (counts non-integer keys too)

Examples

mp.utils.hex_to_bytes("4865")           -- {0x48, 0x65}
mp.utils.bytes_to_string({72, 101})     -- "He"
mp.utils.is_ascii({0x48, 0x65})         -- true
mp.utils.le32(0x78, 0x56, 0x34, 0x12)   -- 0x12345678

local cfg = mp.utils.json_parse('{"target":"STM32F1"}')
local s = mp.utils.json_encode({a = 1, b = "x"})

local t = mp.utils.timer()
mp.sleep(100)
mp.log.info("elapsed: " .. t:elapsed_ms() .. " ms")

mp.log.info(mp.utils.datetime())  -- "2026-05-08 14:30:00"