Buffer¶

Buffer objects are used for working with binary data, e.g. returned from asJPEG. They can be used much like arrays, but are much more efficient since they only store bytes.

Constructors¶

class Buffer(data)¶

Creates a new Buffer initialized with contents from data.

Arguments:

data (Buffer | ArrayBuffer | Uint8Array | string | null) – Contents used to populate buffer, or leave it empty if null.

var buffer = new mupdf.Buffer("hello world")

Instance properties¶

Buffer.prototype.length¶

The number of bytes in this buffer (read-only).

Throws:: TypeError on attempted writes.
Returns:: number

Buffer.prototype.[n]¶

only mutool run

Get or set the byte at index n.

See readByte() and writeByte() for the equivalent in mupdf.js.

Throws:: RangeError on out of bounds accesses.

var byte = buffer[0]

Instance methods¶

Buffer.prototype.asString()¶

Returns the contents of this buffer as a string.

Returns:: string

var str = buffer.asString()

Buffer.prototype.asUint8Array()¶

only mupdf.js

Returns the contents of this buffer as a Uint8Array.

Returns:: Uint8Array

var arr = buffer.asUint8Array()

Buffer.prototype.getLength()¶

Returns the number of bytes in this buffer.

Returns:: number

var length = buffer.getLength()

Buffer.prototype.readByte(at)¶

Returns the byte at the specified index at if within 0 <= at < getLength(). Otherwise returns undefined.

Arguments:

at (number) – Index to read byte at.

Returns:

number

buffer.readByte(0)

Buffer.prototype.slice(start, end)¶

Create a new buffer containing a (subset of) the data in this buffer. Start and end are offsets from the beginning of this buffer, and if negative from the end of this buffer. If start points to the end of this buffer, or if end point to at or before start, then an empty buffer will be returned.

Arguments:

start (number) – Start index.
end (number) – End index (optional).

Returns:

Buffer

var buffer = new mupdf.Buffer()
buffer.write("hello world") // buffer contains "hello world"
var newBuffer = buffer.slice(1, -1) // newBuffer contains "ello worl"

Buffer.prototype.write(str)¶

Append the string as UTF-8 to the end of this buffer.

Arguments:

str (string) – String to append.

buffer.write("hello world")

Buffer.prototype.writeBuffer(data)¶

Append the contents of the data buffer to the end of this buffer.

Arguments:

data (Buffer | ArrayBuffer | Uint8Array | string) – Data buffer to append.

buffer.writeBuffer(anotherBuffer)

Buffer.prototype.writeByte(byte)¶

Append a single byte to the end of this buffer. Only the least significant 8 bits of the value are appended.

Arguments:

byte (number) – The byte value to append.

buffer.writeByte(0x2a)

Buffer.prototype.writeLine(str)¶

Append string to the end of this buffer ending with a newline.

Arguments:

str (string) – String to append.

buffer.writeLine("a line")

Buffer.prototype.writeRune(c)¶

only mutool run

Encode a unicode character as UTF-8 and append to the end of the buffer.

Arguments:

c (number) – The character unicode codepoint.

buffer.writeRune(0x4f60) // To append U+4f60, 你
buffer.writeRune(0x597d) // To append U+597d, 好
buffer.writeRune(0xff01) // To append U+ff01, ！

Buffer.prototype.save(filename)¶

Write the contents of the buffer to a file.

Arguments:

filename (string) – Filename to save to.

buffer.save("buffer.dat")