JavaScript arraybuffer operations for typed arrays and views

Personal understanding of typed data is the memory allocation area, the storage of different data is the view DataView

var buffers = [];

var json = {"id": +, "name": "China"};
var buf = new Buffer (json.stringify (JSON));

Define a Arraybuffer

var ab = new ArrayBuffer (6);//define a 6-byte memory area

var ablength = AB.BYTELENGTH;//6

Check if memory allocation is successful you need to compare ablength

if (ablength = = = 6) {//Success}else{//Failure}

Arraybuffer can store multiple types of data, and different types of storage are DataView

The types of DataView are as follows:

• Int8array:8-bit signed integer, 1 bytes in length.
• Uint8array:8-bit unsigned integer, 1 bytes in length.
• INT16ARRAY:16-bit signed integer, 2 bytes in length.
• uint16array:16-bit unsigned integer, 2 bytes in length.
• INT32ARRAY:32-bit signed integer, 4 bytes in length.
• uint32array:32-bit unsigned integer, 4 bytes in length.
• float32array:32 bit floating point number, length 4 bytes.
• float64array:64 bit floating point number, length 8 bytes.

Construction of Dataview,new DataView (ArrayBuffer); The parameter must be present and must be Arraybuffer

The DataView view provides the following methods for writing to memory: There are three parameters the first parameter is the byte ordinal, the second parameter is the write data, the third parameter is True|false optional, true is low-byte write, the default is high-byte write

• SetInt8: Writes a 1-byte 8-bit integer.
• SetUint8: Writes a 1-byte, 8-bit unsigned integer.
• SetInt16: Writes a 2-byte 16-bit integer.
• SetUint16: Writes a 2-byte, 16-bit unsigned integer.
• SetInt32: Writes a 4-byte 32-bit integer.
• SetUint32: Writes a 4-byte, 32-bit unsigned integer.
• SetFloat32: Writes a 4-byte 32-bit floating-point number.
• SetFloat64: Writes a 8-byte 64-bit floating-point number.

method to read memory

• GetInt8: Reads 1 bytes and returns a 8-bit integer.
• GetUint8: Reads 1 bytes and returns an unsigned 8-bit integer.
• GetInt16: Reads 2 bytes and returns a 16-bit integer.
• GetUint16: Reads 2 bytes and returns an unsigned 16-bit integer.
• GetInt32: Reads 4 bytes and returns a 32-bit integer.
• GetUint32: Reads 4 bytes and returns an unsigned 32-bit integer.
• GetFloat32: Reads 4 bytes and returns a 32-bit floating-point number.
• GetFloat64: Reads 8 bytes and returns a 64-bit floating-point number.

Storage of data

var dv = new DataView (AB);

Dv.setuint16 (0, Math.pow (2, 16)-1);

Dv.setuint16 (2, Math.pow (2, 16)-2);

Dv.setuint16 (4, buf.length);

Buffers.push (New Buffer (New Uint8array (AB)));

Buffers.push (BUF);

var resbuf = Buffer.concat (buffers);//The total combination of Buffer;

Unpacking the data

var a1 = resbuf.readuint16be (0);//Reads a 16-bit unsigned integer value from the Cache object, in high-byte-order storage mode

var a2 = Resbuf.readuint16be (2);

var a3 = Resbuf.readuint16be (4);

var str = Resbuf.slice (6, A3 + 6);//Take string contents

Finally, the A1,A2,A3,STR is the data that was just stored

JavaScript arraybuffer operations for typed arrays and views