2.0 KiB
2.0 KiB
byteutil library
The library provides functions for working with byte arrays represented as tables or Bytearrays.
byteutil.pack(format: str, ...) -> Bytearray
byteutil.tpack(format: str, ...) -> table
Returns a byte array containing the provided values packed according to the format string. The arguments must exactly match the values required by the format.
The format string consists of special characters and value characters.
Special characters specify the byte order for the subsequent values:
| Character | Byte Order |
|---|---|
@ |
System |
= |
System |
< |
Little-endian |
> |
Big-endian |
! |
Network (big-endian) |
Value characters describe the type and size.
| Character | C++ Equivalent | Lua Type | Size |
|---|---|---|---|
b |
int8_t | number | 1 byte |
B |
uint8_t | number | 1 byte |
? |
bool | boolean | 1 byte |
h |
int16_t | number | 2 bytes |
H |
uint16_t | number | 2 bytes |
i |
int32_t | number | 4 bytes |
I |
uint32_t | number | 4 bytes |
l |
int64_t | number | 8 bytes |
L |
uint64_t | number | 8 bytes |
Warning
Due to the absence of an integer type in Lua for values
landL, only an output size of 8 bytes is guaranteed; the value may differ from what is expected.
byteutil.unpack(format: str, bytes: table|Bytearray) -> ...
Extracts values from a byte array based on a format string.
Example:
debug.print(byteutil.tpack('>iBH?', -8, 250, 2019, true))
-- outputs:
-- debug.print(
-- {
-- 255,
-- 255,
-- 255,
-- 248,
-- 250,
-- 7,
-- 227,
-- 1
-- }
-- )
local bytes = byteutil.pack('>iBH?', -8, 250, 2019, true)
print(byteutil.unpack('>iBH?', bytes))
-- outputs:
-- -8 250 2019 true