Source: Roblox Creator Hub · CC BY 4.0 · View source · Code samples: MIT Imported 2026-10-03. Formatting adapted for this site.
buffer
A buffer is an object that represents a fixed-size mutable block of memory. The buffer library provides functions for creation and manipulation of buffer objects, providing all its functions inside the global buffer variable.
Buffer is intended to be used a low-level binary data storage structure, replacing the uses of string.pack() and string.unpack(). Use cases include reading and writing existing binary formats, working with data in a more compact form, serialization to custom binary formats, and general work with native memory types like fixed-length integers and floats.
When passed through Roblox APIs, including sending a buffer through custom events, the identity of the buffer object is not preserved and the target will receive a copy. Similar to other limitations, the same buffer object cannot be used from multiple Actor scripts (Parallel Luau).
Many of the functions accept an offset in bytes from the start of the buffer. Offset of 0 from the start of the buffer memory block accesses the first byte. All offsets, counts and sizes should be non-negative integer numbers. If the bytes that are accessed by any read or write operation are outside the buffer memory, an error is thrown.
The read and write methods that work with integers and floats use little-endian encoding.
Functions
| Name | Type / Returns | Description |
|---|---|---|
| buffer.create | buffer | Creates a buffer. |
| buffer.fromstring | buffer | Creates a buffer from a string. |
| buffer.tostring | string | Converts a buffer to a string. |
| buffer.len | number | Returns the size of the buffer in bytes. |
| buffer.readbits | number | Reads a range of bits into an unsigned integer from the buffer based on a specific bitCount integer from 0 to 32, inclusive. |
| buffer.readi8 | number | Reads an 8-bit signed integer from the buffer. |
| buffer.readu8 | number | Reads an 8-bit unsigned integer from the buffer. |
| buffer.readi16 | number | Reads a 16-bit signed integer from the buffer. |
| buffer.readu16 | number | Reads a 16-bit unsigned integer from the buffer. |
| buffer.readi32 | number | Reads a 32-bit signed integer from the buffer. |
| buffer.readu32 | number | Reads a 32-bit unsigned integer from the buffer. |
| buffer.readf32 | number | Reads a 32-bit floating-point value from the buffer. |
| buffer.readf64 | number | Reads a 64-bit floating-point value from the buffer. |
| buffer.writebits | () | Writes data to the buffer based on a specific bitCount integer from 0 to 32, inclusive. |
| buffer.writei8 | () | Writes an 8-bit signed integer to the buffer. |
| buffer.writeu8 | () | Writes an 8-bit unsigned integer to the buffer. |
| buffer.writei16 | () | Writes a 16-bit signed integer to the buffer. |
| buffer.writeu16 | () | Writes a 16-bit unsigned integer to the buffer. |
| buffer.writei32 | () | Writes a 32-bit signed integer to the buffer. |
| buffer.writeu32 | () | Writes a 32-bit unsigned integer to the buffer. |
| buffer.writef32 | () | Writes a 32-bit floating-point value to the buffer. |
| buffer.writef64 | () | Writes a 64-bit floating-point value to the buffer. |
| buffer.readstring | string | Reads a string from the buffer. |
| buffer.writestring | () | Writes a string to the buffer. |
| buffer.copy | () | Copies bytes between buffers. |
| buffer.fill | () | Sets a region of the buffer memory to some 8-bit unsigned integer value. |
buffer.create
Creates a buffer of the requested size with all bytes initialized to 0. Size limit is 1 GiB, or 1,073,741,824 bytes. Keep in mind that larger buffers might fail to allocate if device is running low on memory.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| size | number | Size of the buffer in bytes. Must be a positive integer. |
Returns
| Type | Description |
|---|---|
| buffer |
buffer.fromstring
Creates a buffer initialized to the contents of the string. The size of the buffer equals the length of the string.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| str | string | The string whose bytes initialize the new buffer. |
Returns
| Type | Description |
|---|---|
| buffer |
buffer.tostring
Returns the buffer data as a string.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to convert. |
Returns
| Type | Description |
|---|---|
| string |
buffer.len
Returns the size of the buffer in bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to get the size of. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readbits
Reads a range of bits into an unsigned integer from the buffer based on a specific bitCount integer from 0 to 32, inclusive. For example:
buffer.readbits(b, 0, 8)is equivalent tobuffer.readu8(b, 0).buffer.readbits(b, 0, 16)is equivalent tobuffer.readu16(b, 0).buffer.readbits(b, 0, 32)is equivalent tobuffer.readu32(b, 0).buffer.readbits(b, 0, 24)reads 24 bits from the buffer.
Note that 0 bit width is supported only to not error in generalized cases where bit count is dynamic, and reading 0 bits returns 0. Also note that, since the max size of the buffer is 1 GB, bitOffset cannot be handled as a 32‑bit integer number like byte offset in other buffer functions.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| bitOffset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| bitCount | number | Integer bit count to read. Error is thrown if this value is not in range of 0 to 32, inclusive. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readi8
Reads the data from the buffer by reinterpreting bytes at the offset as an 8-bit signed integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readu8
Reads the data from the buffer by reinterpreting bytes at the offset as an 8-bit unsigned integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readi16
Reads the data from the buffer by reinterpreting bytes at the offset as a 16-bit signed integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readu16
Reads the data from the buffer by reinterpreting bytes at the offset as a 16-bit unsigned integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readi32
Reads the data from the buffer by reinterpreting bytes at the offset as a 32-bit signed integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readu32
Reads the data from the buffer by reinterpreting bytes at the offset as a 32-bit unsigned integer and converting it into a number.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readf32
Reads the data from the buffer by reinterpreting bytes at the offset as a 32-bit floating-point value and converting it into a number. If the floating-point value matches any bit patterns that represent NaN (not a number), the returned value may be converted to a different quiet NaN representation.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.readf64
Reads the data from the buffer by reinterpreting bytes at the offset as a 64-bit floating-point value and converting it into a number. If the floating-point value matches any bit patterns that represent NaN (not a number), the returned value may be converted to a different quiet NaN representation.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. |
Returns
| Type | Description |
|---|---|
| number |
buffer.writebits
Writes data to the buffer based on a specific bitCount integer from 0 to 32, inclusive. value is treated as an unsigned 32‑bit number and only bitCount least significant bits are written.
Note that 0 bit width is supported only to not error in generalized cases where bit count is dynamic, and writing 0 bits has no effect. Also note that, since the max size of the buffer is 1 GB, bitOffset cannot be handled as a 32‑bit integer number like byte offset in other buffer functions.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| bitOffset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| bitCount | number | Integer bit count to write. Error is thrown if this value is not in range of 0 to 32, inclusive. | |
| value | number | Unsigned 32‑bit number. Only bitCount least significant bits are written. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writei8
Writes data to the buffer by converting the number into an 8-bit signed integer and writing a single byte.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [-128, 127]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writeu8
Writes data to the buffer by converting the number into an 8-bit unsigned integer and writing a single byte.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [0, 255]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writei16
Writes data to the buffer by converting the number into a 16-bit signed integer and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [-32,768, 32,767]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writeu16
Writes data to the buffer by converting the number into a 16-bit unsigned integer and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [0, 65,535]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writei32
Writes data to the buffer by converting the number into a 32-bit signed integer and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [-2,147,483,648, 2,147,483,647]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writeu32
Writes data to the buffer by converting the number into a 32-bit unsigned integer and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [0, 4,294,967,295]. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writef32
Writes data to the buffer by converting the number into a 32-bit floating-point value and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | A single-precision floating-point number. |
Returns
| Type | Description |
|---|---|
| () |
buffer.writef64
Writes data to the buffer by converting the number into a 64-bit floating-point value and reinterpreting it as individual bytes.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | A double-precision floating-point number. |
Returns
| Type | Description |
|---|---|
| () |
buffer.readstring
Reads a string of length count from the buffer at the specified offset.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to read from. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| count | number | Length to read. |
Returns
| Type | Description |
|---|---|
| string |
buffer.writestring
Writes data from a string into the buffer at the specified offset. If an optional count is specified, only count bytes are taken from the string.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | The buffer to write to. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | string | Data to write. | |
| count | number? | Number of bytes to take from the string. This value cannot be larger than the string length. |
Returns
| Type | Description |
|---|---|
| () |
buffer.copy
Copies count bytes from source starting at offset sourceOffset into the target at targetOffset.
It's possible for source and target to be the same. Copying an overlapping region inside the same buffer acts as if the source region is copied into a temporary buffer and then that buffer is copied over to the target.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| target | buffer | Buffer to copy data into. | |
| targetOffset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| source | buffer | Buffer to take the data from. | |
| sourceOffset | number? | 0 | Offset from the beginning of the buffer memory, starting from 0. |
| count | number? | Number of bytes to copy. If omitted, the whole source data starting from sourceOffset is taken. |
Returns
| Type | Description |
|---|---|
| () |
buffer.fill
Sets count bytes in the buffer starting at the specified offset to value.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| b | buffer | Buffer to write the data into. | |
| offset | number | Offset from the beginning of the buffer memory, starting from 0. | |
| value | number | An integer number in range [0, 255]. | |
| count | number? | Number of bytes to write. If omitted, all bytes after the specified offset are set. |
Returns
| Type | Description |
|---|---|
| () |