JSDoc: Class: BufferQueueReader

new BufferQueueReader(buffer1, buffer2, bufferN)

A class providing extended functionality for reading lists/streams of Buffer instances.

Parameters:

Name	Type	Description
`buffer1`	Buffer	An optional buffer to push.
`buffer2`	Buffer	An optional buffer to push.
`bufferN`	Buffer	An optional buffer to push.

Properties:

Name	Type	Description
`length`	Number	The remaining length of the reader.

Source:

lib/BufferQueueReader.js, line 31

Throws:

If any of the specified buffers aren't instances of `Buffer`.

Type: Error

Example

var reader = new BufferQueueReader(new Buffer(3), new Buffer(8));

reader.push(new Buffer(10));
reader.push(new Buffer(5));
reader.push(new Buffer(16));

console.log('int16=', reader.shiftInt16());
console.log('uint32=', reader.shiftUInt32());
console.log('bits=', reader.readBits(0, 12));

reader.skip(2);

console.log('double=', reader.shiftDouble());

Methods

copy(targetBuffer, targetStart, sourceStart, sourceEnd) → {Number}

Copies bytes from the reader to the specified target buffer.

Parameters:

Name	Type	Description
`targetBuffer`	Buffer	A buffer to copy to.
`targetStart`	Number=0	A position at which writing to the buffer should begin. Defaults to 0 (the beginning).
`sourceStart`	Number=0	A position from which writing from the reader should begin. Defaults to 0 (the beginning).
`sourceEnd`	Number=this.length	A position at which writing from the reader should end. Defaults to the end (the reader's length).

Source:

lib/BufferQueueReader.js, line 193

Returns:

A number of bytes written.

Type: Number

Throws:

If the specified target buffer is not an instance of Buffer.

Type

Error
If the specified target start index is not a number between 0 and the target buffer's length.

Type

Error
If the specified source start index is not a number between 0 and the reader's length (exclusive).

Type

Error
If the specified source end index is not a number between 0 (exclusive) and the reader's length.

Type

Error
If the specified source start index is greater than or equal to the source end index.

Type

Error

Example

var buffer = new Buffer(10);

reader.copy(buffer, 5, 0, 5);

indexOf(searchElement, fromIndex) → {Number}

Returns a position of the next occurence of the specified byte after the specified starting index.

Parameters:

Name	Type	Description
`searchElement`	Number	A byte value to search for.
`fromIndex`	Number=0	A starting index. Defaults to 0 (the beginning).

Source:

lib/BufferQueueReader.js, line 127

Returns:

A position of the found element (starting at 0) or -1 if the search element was not found.

Type: Number

Throws:

If the search element is not a number between 0x00 and 0xFF.

Type

Error
If the starting index is not a number between 0 and the reader's length.

Type

Error

Example

var index = reader.indexOf(0xFF, 20);

push(buffer1, buffer2, bufferN)

Adds the specified buffers to the reader.

Empty buffers are ignored.

Parameters:

Name	Type	Description
`buffer1`	Buffer	A buffer to push.
`buffer2`	Buffer	An optional buffer to push.
`bufferN`	Buffer	An optional buffer to push.

Source:

lib/BufferQueueReader.js, line 55

Throws:

If any of the specified buffers aren't an instance of `Buffer`.

Type: Error

Example

reader.push(new Buffer('Hello'), new Buffer(' '), new Buffer('World!'));

readBits(offset, count) → {Array.}

Returns an array of bits (boolean values) starting at the specified offset.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 1.
`count`	Number	A number of bits to read. Must be between 1 and the reader's length multiplied by 8 minus the starting index.

Source:

lib/BufferQueueReader.js, line 574

Returns:

An array of bits.

Type: Array.<Boolean>

Throws:

If the specified count is not a number between 1 and the reader's length multiplied by 8 minus the starting index.

Type: Error

Example

var bitsArray = reader.readBits(5, 13);

readBuffer(offset, count) → {Buffer}

Returns the specified number of bytes as an instance of Buffer starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus the specified count.
`count`	Number	A number of bytes to read. Must be between 1 and the reader's length minus the offset.

Source:

lib/BufferQueueReader.js, line 692

Returns:

A Buffer of bytes.

Type: Buffer

Throws:

If the specified offset exceeds the reader's boundries.

Type

Error
If the specified count is not a number between 1 and the reader's length minus the offset.

Type

Error

Example

var buffer = reader.readBuffer(5, 10);

readByte(offset) → {Number}

Returns a byte at the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 1.

Source:

lib/BufferQueueReader.js, line 588

Returns:

A number between 0x00 and 0xFF.

Type: Number

Throws:

If the reader is empty.

Type: Error

Example

var byteValue = reader.readByte(1);

readBytes(offset, count) → {Array.}

Returns the specified number of bytes starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus the specified count.
`count`	Number	A number of bytes to read. Must be between 1 and the reader's length minus the offset.

Source:

lib/BufferQueueReader.js, line 635

Returns:

An array of bytes.

Type: Array.<Number>

Throws:

If the specified offset exceeds the reader's boundries.

Type

Error
If the specified count is not a number between 1 and the reader's length minus the offset.

Type

Error

Example

var bytesArray = reader.readBytes(0, 6);

readChar(offset) → {String}

Returns an ASCII character at the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 1.

Source:

lib/BufferQueueReader.js, line 619

Returns:

An ASCII character.

Type: String

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var charValue = reader.readChar(4);

readDouble(offset, littleEndian) → {Number}

Returns a signed 64 bit floating-point number as defined in IEEE 754.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 8.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 912

Returns:

A 64 bit floating-point number.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var doubleBE = reader.readDouble(0);
var doubleLE = reader.readDouble(8, true);

readFloat(offset, littleEndian) → {Number}

Returns a signed 32 bit floating-point number as defined in IEEE 754.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 4.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 896

Returns:

A 32 bit floating-point number.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var floatBE = reader.readFloat(0, );
var floatLE = reader.readFloat(4, true);

readInt16(offset, littleEndian) → {Number}

Returns a signed 16 bit integer starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 2.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 818

Returns:

A number between -32768 and 32767.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var int16BE = reader.readInt16(0);
var int16LE = reader.readInt16(2, true);

readInt32(offset, littleEndian) → {Number}

Returns a signed 32 bit integer starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 4.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 834

Returns:

A number between -2147483648 and 2147483647.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var int32BE = reader.readInt32(0);
var int32LE = reader.readInt32(4, true);

readInt8(offset) → {Number}

Returns a signed 8 bit integer at the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 1.

Source:

lib/BufferQueueReader.js, line 802

Returns:

A number between -128 and 127.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type

Error
If the reader is empty.

Type

Error

Example

var int8 = reader.readInt8(5);

readString(offset, length, encoding) → {String}

Returns the specified number of bytes as a string with the specified encoding.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus the specified length.
`length`	Number	A number of bytes to read. Must be between 1 and the reader's length minus the offset.
`encoding`	String=utf8	An encoding of the string. Defaults to `utf8`.

Source:

lib/BufferQueueReader.js, line 763

Returns:

A string of the specified length.

Type: String

Throws:

If the specified offset exceeds the reader's boundries.

Type

Error
If the specified length is not a number between 1 and the reader's length.

Type

Error
If the specified encoding is not supported.

Type

Error

Example

var stringValue = reader.readString(1, 12, 'ascii');

readUInt16(offset, littleEndian) → {Number}

Returns an unsigned 16 bit integer starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 2.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 864

Returns:

A number between 0 and 65535.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var uint16BE = reader.readUInt16(0);
var uint16LE = reader.readUInt16(2, true);

readUInt32(offset, littleEndian) → {Number}

Returns an unsigned 32 bit integer starting from the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 4.
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 880

Returns:

A number between 0 and 4294967295.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var uint32BE = reader.readUInt32(0);
var uint32LE = reader.readUInt32(4, true);

readUInt8(offset) → {Number}

Returns an unsigned 8 bit integer at the specified position.

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length minus 1.

Source:

lib/BufferQueueReader.js, line 848

Returns:

A number between 0 and 255.

Type: Number

Throws:

If the specified offset exceeds the reader's boundries.

Type: Error

Example

var uint8 = reader.readUInt8(0);

readZeroString(offset, encoding) → {String}

Returns a string from the specified offset until the first occurence of the NULL character (\0).

Parameters:

Name	Type	Description
`offset`	Number	A starting index. Must be between 0 and the reader's length.
`encoding`	String=utf8	An encoding of the string. Defaults to `utf8`.

Source:

lib/BufferQueueReader.js, line 780

Returns:

A string constructed from the read bytes or empty string if NULL character could not be found.

Type: String

Throws:

If the specified offset exceeds the reader's boundries.

Type

Error
If the specified encoding is not supported.

Type

Error

Example

var stringValue = reader.readZeroString(0, 'utf8');

shiftBits(count) → {Array.}

Shifts an array of bits (boolean values) from the reader.

Decreases the reader's length by a number of bytes that is needed to extract the specified number of bits (e.g. 4, 8 bits=1 byte, 9, 13, 16 bits=2 bytes etc.).

Parameters:

Name	Type	Description
`count`	Number	A number of bits to shift. Must be between 1 and the reader's length multiplied by 8.

Source:

lib/BufferQueueReader.js, line 276

Returns:

An array of bits.

Type: Array.<Boolean>

Throws:

If the specified count is not a number between 1 and the reader's length multiplied by 8.

Type: Error

Example

var bitsArray = reader.shiftBits(13);

shiftBuffer(count) → {Buffer}

Shifts the specified number of bytes as an instance of Buffer.

Decreases the reader's length by the specified byte count.

Parameters:

Name	Type	Description
`count`	Number	A number of bytes to shift. Must be between 1 and the reader's length.

Source:

lib/BufferQueueReader.js, line 380

Returns:

A buffer of the specified size.

Type: Buffer

Throws:

If the specified count is not a number between 1 and the reader's length.

Type: Error

Example

var buffer = reader.shiftBuffer(10);

shiftByte() → {Number}

Shifts a byte from the reader.

Decreases the reader's length by 1.

Source:

lib/BufferQueueReader.js, line 291

Returns:

A number between 0x00 and 0xFF.

Type: Number

Throws:

If the reader is empty.

Type: Error

Example

var byteValue = reader.shiftByte();

shiftBytes(count) → {Array.}

Shifts the specified number of bytes from the reader.

Decreases the reader's length by the specified byte count.

Parameters:

Name	Type	Description
`count`	Number	A number of bytes to shift. Must be between 1 and the reader's length.

Source:

lib/BufferQueueReader.js, line 339

Returns:

An array of bytes.

Type: Array.<Number>

Throws:

If the specified count is not a number between 1 and the reader's length.

Type: Error

Example

var bytesArray = reader.shiftBytes(6);

shiftChar() → {String}

Shifts an ASCII character from the reader.

Decreases the reader's length by 1.

Source:

lib/BufferQueueReader.js, line 323

Returns:

An ASCII character.

Type: String

Throws:

If the reader is empty.

Type: Error

Example

var charValue = reader.shiftChar();

shiftDouble(littleEndian) → {Number}

Shifts a signed 64 bit floating-point number as defined in IEEE 754.

Decreases the reader's length by eight bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 559

Returns:

A 64 bit floating-point number.

Type: Number

Throws:

If the reader's length is less than 8.

Type: Error

Example

var doubleBE = reader.shiftDouble();
var doubleLE = reader.shiftDouble(true);

shiftFloat(littleEndian) → {Number}

Shifts a signed 32 bit floating-point number as defined in IEEE 754.

Decreases the reader's length by four bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 542

Returns:

A 32 bit floating-point number.

Type: Number

Throws:

If the reader's length is less than 4.

Type: Error

Example

var floatBE = reader.shiftFloat();
var floatLE = reader.shiftFloat(true);

shiftInt16(littleEndian) → {Number}

Shifts a signed 16 bit integer.

Decreases the reader's length by two bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 459

Returns:

A number between -32768 and 32767.

Type: Number

Throws:

If the reader's length is less than 2.

Type: Error

Example

var int16BE = reader.shiftInt16();
var int16LE = reader.shiftInt16(true);

shiftInt32(littleEndian) → {Number}

Shifts a signed 32 bit integer.

Decreases the reader's length by four bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 476

Returns:

A number between -2147483648 and 2147483647.

Type: Number

Throws:

If the reader's length is less than 4.

Type: Error

Example

var int32BE = reader.shiftInt32();
var int32LE = reader.shiftInt32(true);

shiftInt8() → {Number}

Shifts a signed 8 bit integer.

Decreases the reader's length by one byte.

Source:

lib/BufferQueueReader.js, line 442

Returns:

A number between -128 and 127.

Type: Number

Throws:

If the reader is empty.

Type: Error

Example

var int8 = reader.shiftInt8();

shiftString(length, encoding) → {String}

Shifts the specified number of bytes as a string with the specified encoding.

Decreases the reader's length by the specified byte count.

Parameters:

Name	Type	Description
`length`	Number	A number of bytes to shift. Must be between 1 and the reader's length.
`encoding`	String=utf8	An encoding of the string. Defaults to `utf8`.

Source:

lib/BufferQueueReader.js, line 399

Returns:

A string of the specified length.

Type: String

Throws:

If the specified length is not a number between 1 and the reader's length.

Type

Error
If the specified encoding is not supported.

Type

Error

Example

var stringValue = reader.shiftString(12, 'ascii');

shiftUInt16(littleEndian) → {Number}

Shifts an unsigned 16 bit integer.

Decreases the reader's length by two bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 508

Returns:

A number between 0 and 65535.

Type: Number

Throws:

If the reader's length is less than 2.

Type: Error

Example

var uint16BE = reader.shiftUInt16();
var uint16LE = reader.shiftUInt16(true);

shiftUInt32(littleEndian) → {Number}

Shifts an unsigned 32 bit integer.

Decreases the reader's length by four bytes.

Parameters:

Name	Type	Description
`littleEndian`	Boolean	Whether to use little endian instead of big endian.

Source:

lib/BufferQueueReader.js, line 525

Returns:

A number between 0 and 4294967295.

Type: Number

Throws:

If the reader's length is less than 4.

Type: Error

Example

var uint32BE = reader.shiftUInt32();
var uint32LE = reader.shiftUInt32(true);

shiftUInt8() → {Number}

Shifts an unsigned 8 bit integer.

Decreases the reader's length by one byte.

Source:

lib/BufferQueueReader.js, line 491

Returns:

A number between 0 and 255.

Type: Number

Throws:

If the reader is empty.

Type: Error

Example

var uint8 = reader.shiftUInt8();

shiftZeroString(encoding) → {String}

Shifts a string from the beginning of the reader until the first occurence of the NULL character (\0).

Decreases the reader's length by the returned string's length plus one.

Parameters:

Name	Type	Description
`encoding`	String=utf8	An encoding of the string. Defaults to `utf8`.

Source:

lib/BufferQueueReader.js, line 416

Returns:

A string constructed from the shifted bytes or empty string if NULL character could not be found.

Type: String

Throws:

If the specified encoding is not supported.

Type: Error

Example

var stringValue = reader.shiftZeroString('utf8');

skip(count)

Skips the specified number of bytes.

If the byte count was not specified or it's value is greater than the length of the reader, skips all the bytes to the end.

Parameters:

Name	Type	Description
`count`	Number=this.length	A number of bytes to skip. Defaults to the reader's length.

Source:

lib/BufferQueueReader.js, line 88

Throws:

If the count is not a number greater than or equal to 0.

Type: Error

Example

reader.skip(10);