@ntrip/bit-buffer v0.3.4

BitBuffer

BitBuffer provides two objects, BitView and BitStream. BitView is a wrapper for ArrayBuffers, similar to JavaScript's DataView, but with support for bit-level reads and writes. BitStream is a wrapper for a BitView used to help maintain your current buffer position, as well as to provide higher-level read / write operations such as for ASCII strings.

BitView

Attributes

bb.buffer  // Underlying Buffer.

bb.bigEndian = false; // Switch to little endian (default is big)

Methods

BitView(buffer, optional byteStart, optional byteEnd)

Default constructor, takes in a single argument of a Buffer. Optional are the byteStart and byteEnd arguments to offset and truncate the view's representation of the buffer.

getBits(offset, bits, signed)

Reads bits number of bits starting at offset.

getInt8, getUint8, getInt16, getUint16, getInt32, getUint32(offset)

Shortcuts for getBits, setting the correct bits / signed values.

setBits(offset, value, bits)

Sets bits number of bits starting at offset.

setInt8, setUint8, setInt16, setUint16, setInt32, setUint32(offset)

Shortcuts for setBits, setting the correct bits count.

getBuffer(offset, byteLength, optional buffer)

Reads byteLength bytes starting at offset into a Buffer.

writeBuffer(offset, buffer)

Writes the contents of buffer starting at offset.

BitStream

Attributes

bb.index;           // Get the current index in bits
bb.index = 0;       // Set the current index in bits

bb.byteIndex;       // Get current index in bytes.
bb.byteIndex = 0;   // Set current index in bytes.

bb.view;        // Underlying BitView
bb.buffer;      // Underlying BitView buffer

bb.length;      // Get the length of the stream in bits
bb.byteLength;  // Get the length of the stream in bytes

bb.bitsLeft;    // The number of bits left in the stream

bb.bigEndian = true;    // Switch to big endian (default is little)

Methods

BitStream(view)

Default constructor, takes in a single argument of a BitView.

BitSteam(buffer, optional byteOffset, optional byteLength)

Shortcut constructor that initializes a new BitView(buffer, byteOffset, byteLength) for the stream to use.

readBits(bits, signed)

Returns bits numbers of bits from the view at the current index, updating the index.

writeBits(value, bits)

Sets bits numbers of bits from value in the view at the current index, updating the index.

readUint8(), readUint16(), readUint32(), readInt8(), readInt16(), readInt32()

Read a 8, 16 or 32 bits (unsigned) integer at the current index, updating the index.

writeUint8(value), writeUint16(value), writeUint32(value), writeInt8(value), writeInt16(value), writeInt32(value)

Write 8, 16 or 32 bits from value as (unsigned) integer at the current index, updating the index.

readBoolean()

Read a single bit from the view at the current index, updating the index.

writeBoolean(value)

Write a single bit to the view at the current index, updating the index.

readBuffer(byteLength)

Read byteLength bytes of data from the underlying view as a Buffer, updating the index.

writeBuffer(buffer)

Writes a buffer to the underlying view starting at the current index, updating the index.

readString(byteLength, optional encoding)

Reads byteLength bytes from the underlying view as a string, updating the index. Optional encoding argument sets the string encoding, defaulting to utf-8.

writeString(string, optional byteLength, optional encoding)

Writes a string to the underlying view starting at the current index, updating the index. If the string is longer than byteLength it will be truncated, and if it is shorter 0x00 will be written in its place. Optional encoding argument sets the string encoding, defaulting to utf-8.

license

MIT