# smart-buffer

Introduction

smart-buffer s a Buffer wrapper that adds functionalities such as automatic read/write offset tracking, string manipulation, data insertion, and more.

How to Install

ohpm install @ohos/smart-buffer 

For details, see Installing an OpenHarmony HAR.

How to Use

1.simple use

import { SmartBuffer, SmartBufferOptions } from '@ohos/smart_buffer
    let packet = new SmartBuffer();
    packet.writeUInt16LE(0x0060);
    packet.writeStringNT(username);
    packet.writeStringNT(password);
    packet.writeUInt8(age);
    packet.writeStringNT(country);
    packet.insertUInt16LE(packet.length - 2, 2);

2.creat SmartBuffer object

let buff = SmartBuffer.fromBuffer(buffer);
let buff = SmartBuffer.fromBuffer(buffer, 'ascii'); 

let buff = SmartBuffer.fromSize(1024); 
let buff = SmartBuffer.fromSize(1024, 'utf8');

let buff = SmartBuffer.fromOptions({
    size: 1024,
    encoding: 'ascii'
});
let buff = SmartBuffer.fromOptions({
    buff: buffer
});
let buff = SmartBuffer.fromBuffer(Buffer.from('some string', 'utf8'));
let buff = new SmartBuffer();

3.Writing and inserting data in SmartBuffer.

let buff = SmartBuffer.fromBuffer(new Buffer([1,2,3,4,5,6]));
buff.writeInt8(7, 2);

let buff = SmartBuffer.fromBuffer(new Buffer([1,2,3,4,5,6]));
buff.insertInt8(7, 2);

Available APIs

interface name	parameter	return	explanation
fromBuffer	buff: Buffer.Buffer, encoding?: Buffer.BufferEncoding	SmartBuffer	Using the provided buffer (Buffer) and optional encoding, create a new SmartBuffer instance
fromSize	size: number, encoding?: Buffer.BufferEncoding	SmartBuffer	Create a new SmartBuffer instance using the provided internal buffer size and optional encoding
fromOptions	options: SmartBufferOptions	SmartBuffer	Create a new SmartBuffer instance using the provided SmartBufferOptions or a failure callback
readInt8	offset?: number	number	Read an Int8 value from the current read position or an optionally provided offset.
readInt16BE	offset?: number	number	Read an Int16BE (16-bit integer in big-endian order) value from the current read position or an optionally provided offset.
readInt16LE	offset?: number	number	Read an Int16LE (16-bit integer in little-endian order) value from the current read position or an optionally provided offset.
readInt32BE	offset?: number	number	Read an Int32BE (32-bit integer in big-endian order) value from the current read position or an optionally provided offset.
readInt32LE	offset?: number	number	Read an Int32LE (32-bit integer in little-endian order) value from the current read position or an optionally provided offset.
readBigInt64BE	offset?: number	bigint	Read a BigInt64BE (64-bit big integer in big-endian order) value from the current read position or an optionally provided offset.
readBigInt64LE	offset?: number	bigint	Read a BigInt64LE (64-bit big integer in little-endian order) value from the current read position or an optionally provided offset.
writeInt8	value: number, offset?: number	SmartBuffer	Write an Int8 (8-bit integer) value to the current write position (or at an optional offset).
insertInt8	value: number, offset: number	SmartBuffer	Insert an Int8 (8-bit integer) value at a given offset position.
writeInt16BE	value: number, offset?: number	SmartBuffer	Write an Int16BE (16-bit integer in big-endian order) value to the current write position (or at an optional offset).
insertInt16BE	value: number, offset: number	SmartBuffer	nsert an Int16BE (16-bit integer in big-endian order) value at a given offset position.
writeInt16LE	value: number, offset?: number	SmartBuffer	Write an Int16LE (16-bit integer in little-endian order) value to the current write position (or at an optional offset).
insertInt16LE	value: number, offset: number	SmartBuffer	Insert an Int16LE (16-bit integer in little-endian order) value at a given offset position.
writeInt32BE	value: number, offset?: number	SmartBuffer	When dealing with files or data streams, Int32BE refers to a 32-bit integer represented in "big-endian byte order"
insertInt32BE	value: number, offset: number	SmartBuffer	Insert an Int32BE value at a given offset position.
writeInt32LE	value: number, offset?: number	SmartBuffer	Write an Int32LE value to the current write position.
insertInt32LE	value: number, offset: number	SmartBuffer	Insert an Int32LE value at a given offset position.
writeBigInt64BE	value: bigint, offset?: number	SmartBuffer	Write a BigInt64BE value to the current write position.
insertBigInt64BE	value: bigint, offset: number	SmartBuffer	Insert a BigInt64BE value at a given offset position.
writeBigInt64LE	value: bigint, offset?: number	number	Write a BigInt64LE value to the current write position.
insertBigInt64LE	value: bigint, offset: number	SmartBuffer	insert a BigInt64LE valueat a given offset position.
readUInt8	offset: number	number	Read a UInt8 value from the current read position or an optionally provided offset.
readUInt16BE	offset?: number	number	Read a UInt16BE value from the current read position or an optionally provided offset.
readUInt16LE	offset?: number	number	Read a UInt16LE value from the current read position or an optionally provided offset.
readUInt32BE	offset?: number	number	Read a UInt32BE value from the current read position or an optionally provided offset.
readUInt32LE	offset?: number	number	Read a UInt32LE value from the current read position or an optionally provided offset.
readBigUInt64BE	offset?: number	bigint	Read a BigUInt64BE value from the current read position or an optionally provided offset.
readBigUInt64LE	offset?: number	bigint	Read a BigUInt64LE value from the current read position or an optionally provided offset.
writeUInt8	value: number, offset?: number	SmartBuffer	Write a UInt8 value to the current write position.
insertUInt8	value: number, offset: number	SmartBuffer	Insert a UInt8 value at a given offset position.
writeUInt16BE	value: number, offset?: number	SmartBuffer	Write a UInt16BE value to the current write position.
insertUInt16BE	value: number, offset: number	SmartBuffer	Insert a UInt16BE value at a given offset position.
writeUInt16LE	value: number, offset?: number	SmartBuffer	Write a UInt16LE value to the current write position.
insertUInt16LE	value: number, offset: number	SmartBuffer	Insert a UInt16LE value at a given offset position.
writeUInt32BE	value: number, offset?: number	SmartBuffer	Write a UInt32BE value to the current write position.
insertUInt32BE	value: number, offset: number	SmartBuffer	Insert a UInt32BE value at a given offset position.
writeUInt32LE	value: number, offset?: number	SmartBuffer	Write a UInt32LE value to the current write position.
insertUInt32LE	value: number, offset: number	SmartBuffer	Insert a UInt32LE value at a given offset position.
writeBigUInt64BE	value: bigint, offset?: number	SmartBuffer	Write a BigUInt64BE value to the current write position.
insertBigUInt64BE	value: bigint, offset: number	SmartBuffer	Insert a BigUInt64BE value at a specified offset
writeBigUInt64LE	value: bigint, offset?: number	SmartBuffer	Write a BigUInt64LE value at the current write position
insertBigUInt64LE	value: bigint, offset: number	SmartBuffer	Insert a BigUInt64LE value at a specified offset
readFloatBE	offset?: number	number	Read a FloatBE value from the current read position or an optional offset
readFloatLE	offset: number	number	Read a FloatLE value from the current read position or an optional offset
writeFloatBE	value: number, offset?: number	SmartBuffer	Write a FloatBE value at the current write position
insertFloatBE	value: number, offset: number	SmartBuffer	Insert a FloatBE value at a specified offset
writeFloatLE	value: number, offset?: number	SmartBuffer	Write a FloatLE value at the current write position
insertFloatLE	value: number, offset: number	SmartBuffer	Insert a FloatLE value at a specified offset
readDoubleBE	offset?: number	number	Read a DoubleBE value from the current read position or an optional offset
readDoubleLE	offset: number	number	Read a DoubleLE value from the current read position or an optional offset
writeDoubleBE	value: number, offset?: number	SmartBuffer	Write a DoubleBE value at the current write position
insertDoubleBE	value: number, offset: number	SmartBuffer	Insert a DoubleBE value at a specified offset
writeDoubleLE	value: number, offset?: number	SmartBuffer	Write a DoubleLE value at the current write position
insertDoubleLE	value: number, offset: number	SmartBuffer	Insert a DoubleLE value at a specified offset
readString	arg1?: number / Buffer.BufferEncoding, encoding?: Buffer.BufferEncoding	string	Read a string from the current read position
insertString	value: string, offset: number, encoding?: Buffer.BufferEncoding	SmartBuffer	Insert a string
writeString	value: string, arg2?: number / Buffer.BufferEncoding, encoding?: Buffer.BufferEncoding	SmartBuffer	Write a string
readStringNT	encoding?: Buffer.BufferEncoding	string	Read a null-terminated string from the current read position
insertStringNT	value: string, offset: number, encoding?: Buffer.BufferEncoding	SmartBuffer	Insert a null-terminated string
writeStringNT	value: string, arg2?: number / Buffer.BufferEncoding, encoding?: Buffer.BufferEncoding	SmartBuffer	Write a null-terminated string
readBuffer	length?: number	Buffer.Buffer	Read a buffer from the current read position within the internal buffer
insertBuffer	value: Buffer.Buffer, offset: number	SmartBuffer	Insert a buffer at the current write position
writeBuffer	value: Buffer.Buffer, offset?: number	SmartBuffer	Write a buffer at the current write position
readBufferNT	None	Buffer.Buffer	Read a null-terminated buffer from the current read position
insertBufferNT	value: Buffer.Buffer, offset: number	SmartBuffer	Insert a null-terminated buffer
writeBufferNT	value: Buffer.Buffer, offset?: number	SmartBuffer	Write a null-terminated buffer
clear	None	SmartBuffer	Clear the SmartBuffer instance to its original empty state
remaining	None	number	Retrieve the remaining data to be read from the SmartBuffer instance
readOffset	None	number	Get the current read offset value of the SmartBuffer instance
readOffset	offset: number	void	Set the read offset value of the SmartBuffer instance
writeOffset	None	number	Get the current write offset value of the SmartBuffer instance
writeOffset	offset: number	void	Set the write offset value of the SmartBuffer instance
encoding	None	Buffer.BufferEncoding	Get the currently set string encoding for the SmartBuffer instance
encoding	encoding: Buffer.BufferEncoding	void	Set the string encoding for the SmartBuffer instance
internalBuffer	None	Buffer.Buffer	Retrieve the underlying internal buffer
toBuffer	None	Buffer.Buffer	Get the value of the internally managed buffer
toString	encoding?: Buffer.BufferEncoding	string	Get the string value of the internally managed buffer
destroy	None	SmartBuffer	Destroy the SmartBuffer instance

Constraints

• DevEco Studio ： 5.0.3.300SP2

• OpenHarmony SDK:API12 (5.0.0.22)

Directory Structure

|---- smart_buffer
|     |---- entry  # Sample code
|     |---- buffer  # lib
|	    |----src
          |----main
              |----ets
                  |----smartbuffer.ts #core logic
                  |----utils.ts #utils
|           |---- index.ets  # external Interface
|     |---- README.md  # Readme                 

About obfuscation

• Code obfuscation, please seeCode Obfuscation
• If you want the smart_buffer library not to be obfuscated during code obfuscation, you need to add corresponding exclusion rules in the obfuscation rule configuration file obfuscation-rules.txt：

-keep
./oh_modules/@ohos/smart_buffer

How to Contribute

If you find any problem during the use, submit an issue or a PR to us.

License

This project is licensed under MIT LICENSE. Welcome to enjoy and participate in the open source.