Version12.5.1

You are reading 12.5.1. See this page in 13.4.1.

buffer.Buffer

pseudoAndroidiPhoneiPadmacOSsince 8.2.0

The Buffer class is a global type for dealing with binary data directly. It can be constructed in a variety of ways.

Note that this Buffer class is highly related to the Titanium.Buffer type. Both are wrappers around an underlying array of bytes and can be accessed in an array-like manner:

const value = buffer[index];
buffer[index] = 1;

In fact, this Node.js shim has been written to allow wrapping a Titanium.Buffer into a Node.js compatible instance:

const wrapped = Buffer.from(tiBuffer);

Note that this will result in a slow Buffer instance (because reads/writes pass-through to the underlying Ti.Buffer which in turn goes through the JS/native binding layer). If you only intend to read the data (or do not need to write back to the original Titanium.Buffer) you can perform a one-time copy of the underlying bytes to a faster JS-only Uint8Array:

const fastBuffer = Buffer.from(tiBuffer.toBlob().toArrayBuffer()); // here we're converting from Blob to Ti.Buffer to ArrayBuffer and the shim wraps that copy

Properties 3

buffer

ArrayBuffer

The underlying ArrayBuffer object based on which this Buffer object is created.

This ArrayBuffer is not guaranteed to correspond exactly to the original Buffer. See the notes on buffer.Buffer.byteOffset for details.

byteOffset

Number

The byteOffset of the Buffers underlying ArrayBuffer object.

length

Number

Returns the number of bytes in buf.

Methods 54

compare

Compares buf with target and returns a number indicating whether buf comes before, after, or is the same as target in sort order. Comparison is based on the actual sequence of bytes in each Buffer.

0 is returned if target is the same as buf 1 is returned if target should come before buf when sorted. -1 is returned if target should come after buf when sorted.

Parameters
Parameters	Type	Description
target	buffer.Buffer \| Uint8Array	A `Buffer` or `Uint8Array` with which to compare buf.
targetStart?	Number	The offset within target at which to begin comparison.
targetEnd?	Number	The offset within target at which to end comparison (not inclusive).
sourceStart?	Number	The offset within buf at which to begin comparison.
sourceEnd?	Number	The offset within buf at which to end comparison (not inclusive).

Returns Number

copy

Copies data from a region of buf to a region in target, even if the target memory region overlaps with buf.

Parameters
Parameters	Type	Description
target	buffer.Buffer \| Uint8Array	A `Buffer` or `Uint8Array` with which to compare buf.
targetStart?	Number	The offset within target at which to begin writing.
sourceStart?	Number	The offset within buf at which to begin copying.
sourceEnd?	Number	The offset within buf at which to stop copying (not inclusive).

Returns Number

The number of bytes copied.

entries

Creates and returns an iterator of [index, byte] pairs from the contents of buf.

Returns Object

equals

Returns true if both buf and otherBuffer have exactly the same bytes, false otherwise. Equivalent to buf.compare(otherBuffer) === 0.

Parameters
Parameters	Type	Description
otherBuffer	buffer.Buffer \| Uint8Array	A `Buffer` or `Uint8Array` with which to compare buf.

Returns Boolean

fill

Fills buf with the specified value. If the offset and end are not given, the entire buf will be filled.

Parameters
Parameters	Type	Description
value	String \| Number \| buffer.Buffer \| Uint8Array	The value with which to fill `buf`.
offset?	Number	Number of bytes to skip before starting to fill `buf`.
end?	Number	Where to stop filling `buf` (not inclusive).
encoding?	String	The encoding for `value` if `value` is a string.

Returns buffer.Buffer

A reference to buf.

includes

Equivalent to buf.indexOf() !== -1.

Parameters
Parameters	Type	Description
value	String \| Number \| buffer.Buffer \| Uint8Array	What to search for.
byteOffset?	Number	Where to begin searching in `buf`. If negative, then offset is calculated from the end of `buf`.
encoding?	String	If `value` is a string, this is its encoding.

Returns Boolean

true if value was found in buf, false otherwise.

indexOf

If value is:

a string, value is interpreted according to the character encoding in encoding.
a Buffer or Uint8Array, value will be used in its entirety. To compare a partial Buffer, use buf.slice().
a number, value will be interpreted as an unsigned 8-bit integer value between 0 and 255.

Parameters
Parameters	Type	Description
value	String \| Number \| buffer.Buffer \| Uint8Array	What to search for.
byteOffset?	Number	Where to begin searching in `buf`. If negative, then offset is calculated from the end of `buf`.
encoding?	String	If `value` is a string, this is the encoding used to determine the binary representation of the string that will be searched for in `buf`.

Returns Number

The index of the first occurrence of value in buf, or -1 if buf does not contain value.

keys

Creates and returns an iterator of buf keys (indices).

Returns Object

lastIndexOf

Identical to buf.indexOf(), except the last occurrence of value is found rather than the first occurrence.

Parameters
Parameters	Type	Description
value	String \| Number \| buffer.Buffer \| Uint8Array	What to search for.
byteOffset?	Number	Where to begin searching in `buf`. If negative, then offset is calculated from the end of `buf`.
encoding?	String	If `value` is a string, this is the encoding used to determine the binary representation of the string that will be searched for in `buf`.

Returns Number

The index of the last occurrence of value in buf, or -1 if buf does not contain value.

readDoubleBE

Reads a 64-bit, big-endian double from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 8`.

Returns Number

readDoubleLE

Reads a 64-bit, little-endian double from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 8`.

Returns Number

readFloatBE

Reads a 32-bit, big-endian float from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readFloatLE

Reads a 32-bit, little-endian float from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readInt16BE

Reads a signed 16-bit, big-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 2`.

Returns Number

readInt16LE

Reads a signed 16-bit, little-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 2`.

Returns Number

readInt32BE

Reads a signed 32-bit, big-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readInt32LE

Reads a signed 32-bit, little-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readInt8

Reads a signed 8-bit integer from buf at the specified offset.

Integers read from a Buffer are interpreted as two's complement signed values.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 1`.

Returns Number

readIntBE

Reads byteLength number of bytes from buf at the specified offset and interprets the result as a big-endian, two's complement signed value supporting up to 48 bits of accuracy.

Parameters
Parameters	Type	Description
offset	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - byteLength`.
byteLength	Number	Number of bytes to read. Must satisfy `0 < byteLength <= 6`.

Returns Number

readIntLE

Reads byteLength number of bytes from buf at the specified offset and interprets the result as a little-endian, two's complement signed value supporting up to 48 bits of accuracy.

Parameters
Parameters	Type	Description
offset	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - byteLength`.
byteLength	Number	Number of bytes to read. Must satisfy `0 < byteLength <= 6`.

Returns Number

readUInt16BE

Reads an unsigned 16-bit, big-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 2`.

Returns Number

readUInt16LE

Reads an unsigned 16-bit, little-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 2`.

Returns Number

readUInt32BE

Reads an unsigned 32-bit, big-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readUInt32LE

Reads an unsigned 32-bit, little-endian integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 4`.

Returns Number

readUInt8

Reads an unsigned 8-bit integer from buf at the specified offset.

Parameters
Parameters	Type	Description
offset?	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - 1`.

Returns Number

readUIntBE

Reads byteLength number of bytes from buf at the specified offset and interprets the result as an unsigned big-endian value supporting up to 48 bits of accuracy.

Parameters
Parameters	Type	Description
offset	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - byteLength`.
byteLength	Number	Number of bytes to read. Must satisfy `0 < byteLength <= 6`.

Returns Number

readUIntLE

Reads byteLength number of bytes from buf at the specified offset and interprets the result as an unsigned little-endian value supporting up to 48 bits of accuracy.

Parameters
Parameters	Type	Description
offset	Number	Number of bytes to skip before starting to read. Must satisfy `0 <= offset <= buf.length - byteLength`.
byteLength	Number	Number of bytes to read. Must satisfy `0 < byteLength <= 6`.

Returns Number

slice

Returns a new Buffer that references the same memory as the original, but offset and cropped by the start and end indices.

Parameters
Parameters	Type	Description
start?	Number	here the new Buffer will start.
end?	Number	Where the new Buffer will end (not inclusive).

Returns buffer.Buffer

subarray

Returns a new Buffer that references the same memory as the original, but offset and cropped by the start and end indices.

Parameters
Parameters	Type	Description
start?	Number	here the new Buffer will start.
end?	Number	Where the new Buffer will end (not inclusive).

Returns buffer.Buffer

swap16

Interprets buf as an array of unsigned 16-bit integers and swaps the byte order in-place.

Returns buffer.Buffer

swap32

Interprets buf as an array of unsigned 32-bit integers and swaps the byte order in-place.

Returns buffer.Buffer

swap64

Interprets buf as an array of unsigned 64-bit integers and swaps the byte order in-place.

Returns buffer.Buffer

toJSON

Returns a JSON representation of buf. JSON.stringify() implicitly calls this function when stringifying a Buffer instance.

Returns Object

toString

Decodes buf to a string according to the specified character encoding in encoding. start and end may be passed to decode only a subset of buf.

Parameters
Parameters	Type	Description
encoding?	String	The character encoding to use.
start?	Number	The byte offset to start decoding at.
end?	Number	The byte offset to stop decoding at (not inclusive).

Returns String

values

Creates and returns an iterator for buf values (bytes). This function is called automatically when a Buffer is used in a for..of statement.

Returns Object

write

Writes string to buf at offset according to the character encoding in encoding. The length parameter is the number of bytes to write. If buf did not contain enough space to fit the entire string, only part of string will be written. However, partially encoded characters will not be written.

Parameters
Parameters	Type	Description
string	String	String to write to `buf`.
offset?	Number	Number of bytes to skip before starting to write string.
length?	Number	Maximum number of bytes to write (written bytes will not exceed buf.length - offset).
encoding?	String	The character encoding of string.

Returns Number

Number of bytes written.

writeDoubleBE

Writes value to buf at the specified offset as big-endian. The value must be a JavaScript number. Behavior is undefined when value is anything other than a JavaScript number.

Parameters
Parameters	Type	Description
value	Number	Number to be written to `buf`.
offset?	Number	Number of bytes to skip before starting to write. Must satisfy `0 <= offset <= buf.length - 8`.

Returns Number