A FastBuffer object is a more efficient buffer container for representing a byte sequence of a fixed length. It is used to store binary data.
When the FastBuffer object is constructed using from, only the parameters of the FastBuffer, Uint8Array, string, Array, ArrayBuffer, and SharedArrayBuffer types are supported.
FastBuffer is recommended if high-performance processing of large binary data (such as images, file transfer, and network communication) is required.
The initial APIs of this module are supported since API version 20. Newly added APIs will be marked with a superscript to indicate their earliest API version.
Container classes, implemented in static languages, have restrictions on storage locations and properties, and do not support custom properties or methods.
BufferEncoding
type BufferEncoding = 'ascii' | 'utf8' | 'utf-8' | 'utf16le' | 'ucs2' | 'ucs-2' | 'base64' | 'base64url' | 'latin1' | 'binary' | 'hex'
Enumerates the supported encoding formats.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
| Type | Description |
|---|---|
| 'ascii' | ASCII format. |
| 'utf8' | UTF-8 format. |
| 'utf-8' | UTF-8 format. |
| 'utf16le' | UTF-16LE format. |
| 'ucs2' | Alias of UTF-16LE. |
| 'ucs-2' | Alias of UTF-16LE. |
| 'base64' | Base64 format. |
| 'base64url' | Base64URL format. |
| 'latin1' | Alias of iso-8859-1, which is backward compatible with the ASCII format. |
| 'binary' | Binary format. |
| 'hex' | Hexadecimal format. |
fastbuffer.alloc
alloc(size: number, fill?: string | FastBuffer | number, encoding?: BufferEncoding): FastBuffer
Creates a FastBuffer object of the specified byte length and initializes it. After the call, each byte of the FastBuffer object is filled with the specified fill value. If fill is not specified, the default value 0 is used.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| size | number | Yes | Size of the FastBuffer object to create, in bytes. Value range: 0 <= size <= UINT32_MAX |
| fill | string | FastBuffer | number | No | Value to fill into the new buffer. Default value: 0. |
| encoding | BufferEncoding | No | Encoding format (valid only when fill is a string). The default value is 'utf8'. If an unrecognized encoding format is passed, TypeError is thrown. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Example
import { fastbuffer } from '@kit.ArkTS';
// Create a FastBuffer object with a length of 5, filled with 0 by default.
let buf1 = fastbuffer.alloc(5);
console.info(buf1.toString());
// Output result: 00000
// Create a FastBuffer object with a length of 5, filled with the character 'a'.
let buf2 = fastbuffer.alloc(5, 'a');
// Create a FastBuffer object with a length of 11, filled using base64 encoding.
let buf3 = fastbuffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
console.info(buf2.toString());
// Output: aaaaa
console.info(buf3.toString());
// Output: hello world fastbuffer.allocUninitializedFromPool
allocUninitializedFromPool(size: number): FastBuffer
Creates an uninitialized FastBuffer object of the specified size from the buffer pool. Call fill to initialize the object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| size | number | Yes | Size of the FastBuffer object to create, in bytes. Value range: 0 <= size <= UINT32_MAX |
Return value
| Type | Description |
|---|---|
| FastBuffer | Uninitialized FastBuffer instance. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(10);
buf.fill(0);
// "buf":[0, 0, 0, 0, 0, 0, 0, 0, 0, 0] fastbuffer.allocUninitialized
allocUninitialized(size: number): FastBuffer
Creates an uninitialized FastBuffer object of the specified size. Call fill to initialize the object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| size | number | Yes | Size of the FastBuffer object to create, in bytes. Value range: 0 <= size <= UINT32_MAX |
Return value
| Type | Description |
|---|---|
| FastBuffer | Uninitialized FastBuffer object. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitialized(10);
buf.fill(0);
// "buf":[0, 0, 0, 0, 0, 0, 0, 0, 0, 0] fastbuffer.byteLength
byteLength(value: string | FastBuffer | TypedArray | DataView | ArrayBuffer | SharedArrayBuffer, encoding?: BufferEncoding): number
Returns the number of bytes of the specified content based on different encoding formats.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | FastBuffer | TypedArray | DataView | ArrayBuffer | SharedArrayBuffer | Yes | Specifies the content used to calculate the byte length. |
| encoding | BufferEncoding | No | Encoding format (only meaningful when value is a string). Default value: 'utf8'. Passing an unrecognized encoding throws a TypeError. |
Return value
| Type | Description |
|---|---|
| number | Returns the number of bytes of the specified content. |
Example
import { fastbuffer } from '@kit.ArkTS';
let str = 'hello world';
console.info(`${str}: ${str.length} characters, ${fastbuffer.byteLength(str, 'utf-8')} bytes`);
// Output: hello world: 11 characters, 11 bytes
str = '\u00bd + \u00bc = \u00be';
console.info(`${str}: ${str.length} characters, ${fastbuffer.byteLength(str, 'utf-8')} bytes`);
// Output: ½ + ¼ = ¾: 9 characters, 12 bytes fastbuffer.compare
compare(buf1: FastBuffer | Uint8Array, buf2: FastBuffer | Uint8Array): -1 | 0 | 1
Compares two FastBuffer objects. This API is used for sorting FastBuffer objects.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| buf1 | FastBuffer | Uint8Array | Yes | First object to compare. |
| buf2 | FastBuffer | Uint8Array | Yes | Second object to compare. |
Return value
| Type | Description |
|---|---|
| -1 | 0 | 1 | Returns 0 if buf1 is the same as buf2. Returns 1 if buf1 comes after buf2 when sorted. Returns -1 if buf1 comes before buf2 when sorted. |
Error codes
For details about the following error codes, see Language Basics Library Error Codes.
| ID | Error Message |
|---|---|
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from('1234');
let buf2 = fastbuffer.from('0123');
let compareResult = fastbuffer.compare(buf1, buf2);
console.info(Number(compareResult).toString());
// Output: 1 fastbuffer.concat
concat(list: FastBuffer[] | Uint8Array[], totalLength?: number): FastBuffer
Copies and concatenates the content of the specified byte length in the array, and returns a new FastBuffer object.
If the total length of all objects in the array exceeds totalLength, the length of the returned result will be truncated to totalLength.
If the total length of all objects in the array is less than totalLength, the excess part of the returned result will be padded with zeros.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| list | FastBuffer[] | Uint8Array[] | Yes | Array of FastBuffer or Uint8Array instances to be concatenated. The contents of all objects in the array are copied to the new FastBuffer object in sequence. |
| totalLength | number | No | Total byte length to copy. The default value is the sum of the lengths of all objects in the array. Value range: 0 <= totalLength <= UINT32_MAX. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from('1234');
let buf2 = fastbuffer.from('abcd');
let buf = fastbuffer.concat([buf1, buf2]);
console.info(buf.toString('hex'));
// Output: 3132333461626364 fastbuffer.from
from(array: number[]): FastBuffer
Creates a FastBuffer object with the specified array.
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| array | number[] | Yes | Specified array. The value range of each element in the array is [0, 255]. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);
console.info(buf.toString('hex'));
// Output: 627566666572 fastbuffer.from
from(arrayBuffer: ArrayBuffer | SharedArrayBuffer, byteOffset?: number, length?: number): FastBuffer
Creates a FastBuffer object of the specified length that shares memory with ArrayBuffer.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| arrayBuffer | ArrayBuffer | SharedArrayBuffer | Yes | The underlying ArrayBuffer or SharedArrayBuffer used to create the FastBuffer object. The created FastBuffer shares the same memory area with this object. |
| byteOffset | number | No | Byte offset. The default value is 0. |
| length | number | No | Byte length. Default value: (arrayBuffer.byteLength - byteOffset). Value range: 0 <= length <= arrayBuffer.byteLength - byteOffset. When null is passed, a FastBuffer object with length 0 is returned. |
Return value
| Type | Description |
|---|---|
| FastBuffer | Returns a FastBuffer object that shares the same memory area with the input parameter arrayBuffer. Modifying the data of the FastBuffer object will synchronously modify the data at the corresponding position in the original ArrayBuffer, and modifying the data of the original ArrayBuffer will also synchronously modify the data at the corresponding position in the FastBuffer. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let arrayBuffer = new ArrayBuffer(10);
let buf = fastbuffer.from(arrayBuffer, 0, 2);
console.info(buf.length.toString());
// Output: 2 fastbuffer.from
from(buffer: FastBuffer | Uint8Array): FastBuffer
When the input parameter is a FastBuffer object, a new FastBuffer object is created and the input data is copied. The data of the new and old objects are independent and do not affect each other.
When the input parameter is a Uint8Array object, a new FastBuffer object is created based on its memory. The two objects maintain memory association, and modifying the data of either object synchronously affects the other object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| buffer | FastBuffer | Uint8Array | Yes | Source data used to create a new FastBuffer object. When the input parameter is a FastBuffer, its data is copied to create a new object; when the input parameter is a Uint8Array, a new object is created based on its memory and the memory association is maintained. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Error codes
For details about the error codes, see Universal Error Codes.
| ID | Error Message |
|---|---|
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
// Create a FastBuffer object from a string.
let buf1 = fastbuffer.from('buffer');
// Create a new FastBuffer object with the FastBuffer object type.
let buf2 = fastbuffer.from(buf1);
console.info(buf2.toString());
// Output: buffer
// Create a FastBuffer object of the Uint8Array type to ensure memory sharing between objects.
let uint8Array = new Uint8Array(10);
let buf3 = fastbuffer.from(uint8Array);
// Modify buf3 to verify memory sharing: after buf3 is modified, uint8Array changes synchronously.
buf3.fill(1);
console.info('uint8Array:', uint8Array);
// Output: 1,1,1,1,1,1,1,1,1,1 fastbuffer.from
from(value: string, encoding?: BufferEncoding): FastBuffer
Creates a FastBuffer object based on a string in the given encoding format.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | Yes | String used to create the FastBuffer object. |
| encoding | BufferEncoding | No | Encoding format. The default value is 'utf8'. If an unrecognized encoding format is passed, TypeError is thrown. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Example
import { fastbuffer } from '@kit.ArkTS';
// Create a FastBuffer object from a normal string.
let buf1 = fastbuffer.from('this is a test');
// Create a FastBuffer object from a hex-encoded string.
let buf2 = fastbuffer.from('7468697320697320612074c3a97374', 'hex');
console.info(buf1.toString());
// Output: this is a test
console.info(buf2.toString());
// Output: this is a tést fastbuffer.isBuffer
isBuffer(obj: Object): boolean
Checks whether the specified object is a FastBuffer object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| obj | Object | Yes | Object to determine whether it is a FastBuffer. |
Return value
| Type | Description |
|---|---|
| boolean | Check result. The value true is returned if the object is a FastBuffer object; otherwise, false is returned. |
Example
import { fastbuffer } from '@kit.ArkTS';
let allocResult = fastbuffer.isBuffer(fastbuffer.alloc(10)); // 10: fastbuffer size
console.info('allocResult = ' + allocResult);
// Output result: allocResult = true
let fromResult = fastbuffer.isBuffer(fastbuffer.from('foo'));
console.info('fromResult = ' + fromResult);
// Output result: fromResult = true
let stringResult = fastbuffer.isBuffer('a string');
console.info('stringResult = ' + stringResult);
// Output result: stringResult = false
let arrayResult = fastbuffer.isBuffer([]);
console.info('arrayResult = ' + arrayResult);
// Output result: arrayResult = false
let uint8ArrayResult = fastbuffer.isBuffer(new Uint8Array(1024));
console.info('uint8ArrayResult = ' + uint8ArrayResult);
// Output result: uint8ArrayResult = false fastbuffer.isEncoding
isEncoding(encoding: string): boolean
Checks whether the encoding format is supported.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| encoding | string | Yes | Encoding format to be determined whether it is supported. |
Return value
| Type | Description |
|---|---|
| boolean | Check result. The value true is returned if the encoding format is supported; otherwise, false is returned. |
Example
import { fastbuffer } from '@kit.ArkTS';
console.info(fastbuffer.isEncoding('utf-8').toString());
// Output: true
console.info(fastbuffer.isEncoding('hex').toString());
// Output: true
console.info(fastbuffer.isEncoding('utf/8').toString());
// Output: false
console.info(fastbuffer.isEncoding('').toString());
// Output: false fastbuffer.transcode
transcode(source: FastBuffer | Uint8Array, fromEnc: string, toEnc: string): FastBuffer
Converts a FastBuffer or Uint8Array object from the fromEnc encoding to the toEnc encoding. It is applicable to scenarios where data needs to be converted between different encoding formats. For example, convert UTF-8 encoded data to Latin1 encoding for processing in systems that support only ASCII.
This API supports the following encoding formats: 'ascii', 'utf8', 'utf16le', 'ucs2', 'latin1', and 'binary'.
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| source | FastBuffer | Uint8Array | Yes | Source data object that requires encoding conversion, which will be converted from the fromEnc encoding to the toEnc encoding. |
| fromEnc | string | Yes | Current encoding format. The supported format range is 'ascii' | 'utf8' | 'utf16le' | 'ucs2' | 'latin1' | 'binary'. When an empty string is passed, the encoding format 'utf8' is used. |
| toEnc | string | Yes | Target encoding. The supported format range is 'ascii' | 'utf8' | 'utf16le' | 'ucs2' | 'latin1' | 'binary'. |
Return value
| Type | Description |
|---|---|
| FastBuffer | New FastBuffer object in the target encoding format. |
Example
import { fastbuffer } from '@kit.ArkTS';
let newBuf = fastbuffer.transcode(fastbuffer.from('buffer'), 'utf-8', 'ascii');
console.info('newBuf = ' + newBuf.toString('ascii'));
// Output: newBuf = buffer [h2]Properties
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
| Name | Type | Read-Only | Optional | Description |
|---|---|---|---|---|
| length | number | Yes | No | Length of the FastBuffer object, in bytes. |
| buffer | ArrayBuffer | Yes | No | The ArrayBuffer object corresponding to the underlying FastBuffer. |
| byteOffset | number | Yes | No | The offset of the underlying ArrayBuffer of the current FastBuffer. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('1236');
console.info(JSON.stringify(buf.length));
// Output: 4
let arrayBuffer = buf.buffer;
console.info(JSON.stringify(new Uint8Array(arrayBuffer)));
// Output: {"0":49,"1":50,"2":51,"3":54}
console.info(JSON.stringify(buf.byteOffset));
// Output: 0 [h2]compare
compare(target: FastBuffer | Uint8Array, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): -1 | 0 | 1
Compares the current this object with the target object and returns the comparison result.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| target | FastBuffer | Uint8Array | Yes | Target FastBuffer object to compare. |
| targetStart | number | No | Offset to start in the target instance. Default value: 0. Value range: 0 <= targetStart <= target.length. |
| targetEnd | number | No | Offset to the end of the data to compare in the target FastBuffer object (not inclusive). The default value is the length of the target FastBuffer object. Value range: 0 <= targetEnd <= target.length |
| sourceStart | number | No | Offset to the start of the data to compare in this FastBuffer object. The default value is 0. Value range: 0 <= sourceStart <= this.length |
| sourceEnd | number | No | Offset to the end of the data to compare in this FastBuffer object (not inclusive). The default value is the length of this FastBuffer object. Value range: 0 <= sourceEnd <= this.length |
Return value
| Type | Description |
|---|---|
| -1 | 0 | 1 | Comparison result. -1: This object comes before the target object when sorted. 0: The two objects are the same. 1: This object comes after the target object when sorted. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from([1, 2, 3, 4, 5, 6, 7, 8, 9]);
let buf2 = fastbuffer.from([5, 6, 7, 8, 9, 1, 2, 3, 4]);
// Compare buf1[0,4) with buf2[5,9). The result 0 indicates they are identical.
console.info(buf1.compare(buf2, 5, 9, 0, 4).toString());
// Output: 0
// Compare buf1[4,end) with buf2[0,6). The result -1 indicates buf1 comes first.
console.info(buf1.compare(buf2, 0, 6, 4).toString());
// Output: -1
// Compare buf1[5,end) with buf2[5,6). The result 1 indicates buf1 comes last.
console.info(buf1.compare(buf2, 5, 6, 5).toString());
// Output: 1 [h2]copy
copy(target: FastBuffer| Uint8Array, targetStart?: number, sourceStart?: number, sourceEnd?: number): number
Copies data at the specified position in this FastBuffer object to the specified position in another FastBuffer object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| target | FastBuffer | Uint8Array | Yes | FastBuffer or Uint8Array object to which data is copied. |
| targetStart | number | No | Offset to the start position in the target object where data is copied. The default value is 0. Value range: 0 <= targetStart <= UINT32_MAX |
| sourceStart | number | No | Offset in the this instance from which copying starts. Default value: 0. Value range: 0 <= sourceStart <= UINT32_MAX. |
| sourceEnd | number | No | Offset to the end position in this FastBuffer object (not inclusive). The default value is the length of this FastBuffer object. Value range: 0 <= sourceEnd <= this.length |
Return value
| Type | Description |
|---|---|
| number | Total length of the data copied, in bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
// Create an uninitialized FastBuffer object as the copy source.
let buf1 = fastbuffer.allocUninitializedFromPool(26);
// Create a FastBuffer object filled with '!' as the copy destination.
let buf2 = fastbuffer.allocUninitializedFromPool(26).fill('!');
// Write ASCII characters a-z to buf1.
for (let i = 0; i < 26; i++) {
buf1.writeInt8(i + 97, i);
}
// Copy bytes 16 to 20 of buf1 to the position starting at byte 8 of buf2.
buf1.copy(buf2, 8, 16, 20);
console.info(buf2.toString('ascii', 0, 25));
// Output: !!!!!!!!qrst!!!!!!!!!!!!! [h2]entries
entries(): IterableIterator<[number, number]>
Returns an iterator containing key values and value values, where the key is the byte index position and the value is the byte value at that position.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| IterableIterator<[number, number]> | Iterator that contains the key and value, both of which are of the number type. |
Example
import { fastbuffer } from '@kit.ArkTS';
// Create a FastBuffer object.
let buf = fastbuffer.from('buffer');
// Obtain the entries iterator.
let entryIterator = buf.entries();
// Obtain the first element of the iterator.
let nextEntry: IteratorResult<[number, number]> = entryIterator.next();
// Iterate through the iterator to output each [key, value] pair.
while (!nextEntry.done) {
console.info('fastbuffer: ' + nextEntry.value);
/*
Output result: fastbuffer: 0,98
fastbuffer: 1,117
fastbuffer: 2,102
fastbuffer: 3,102
fastbuffer: 4,101
fastbuffer: 5,114
*/
nextEntry = entryIterator.next();
} [h2]equals
equals(otherBuffer: Uint8Array | FastBuffer): boolean
Checks whether this FastBuffer object is the same as another FastBuffer object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| otherBuffer | Uint8Array | FastBuffer | Yes | Target object for comparison. |
Return value
| Type | Description |
|---|---|
| boolean | Check result. The value true is returned if the two objects are equal byte by byte; otherwise, false is returned. |
Error codes
For details about the error codes, see Universal Error Codes.
| ID | Error Message |
|---|---|
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from('ABC');
let buf2 = fastbuffer.from('414243', 'hex');
let buf3 = fastbuffer.from('ABCD');
console.info(buf1.equals(buf2).toString());
// Output: true
console.info(buf1.equals(buf3).toString());
// Output: false [h2]fill
fill(value: string | FastBuffer | Uint8Array | number, offset?: number, end?: number, encoding?: BufferEncoding): FastBuffer
Fills the data at the specified position of the current object with value. When the length of value is less than the range to be filled, value is repeated cyclically for filling, and the filled FastBuffer object is returned.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | FastBuffer | Uint8Array | number | Yes | Value used for filling. |
| offset | number | No | Offset to the start position in this FastBuffer object where data is filled. The default value is 0. Value range: 0 <= offset <= this.length |
| end | number | No | Offset to the end position in this FastBuffer object (not inclusive). The default value is the length of this FastBuffer object. Value range: 0 <= end <= this.length |
| encoding | BufferEncoding | No | Encoding format (valid only when value is a string). The default value is 'utf8'. If an unrecognized encoding format is passed, TypeError is thrown. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object filled with the specified value. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let filledBuffer = fastbuffer.allocUninitializedFromPool(50).fill('h');
console.info(filledBuffer.toString());
// Output: hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh [h2]includes
includes(value: string | number | FastBuffer | Uint8Array, byteOffset?: number, encoding?: BufferEncoding): boolean
Checks whether this FastBuffer object contains the specified value.
If byteOffset is a positive number, the offset is calculated from 0. If byteOffset is a negative number, the offset is calculated from the end.
If byteOffset is greater than or equal to this.length, false is returned. If byteOffset is less than or equal to -this.length, the system checks whether the value exists in the entire FastBuffer.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | number | FastBuffer | Uint8Array | Yes | Content to search. |
| byteOffset | number | No | Byte offset. If byteOffset is positive, the offset is calculated from 0; if negative, it is calculated from the end. Default value: 0. |
| encoding | BufferEncoding | No | Character encoding format (only meaningful when value is a string). Default value: 'utf8'. Passing an unrecognized encoding throws a TypeError. |
Return value
| Type | Description |
|---|---|
| boolean | Check result. The value true is returned if the object contains the specified value; otherwise, false is returned. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('this is a buffer');
console.info(buf.includes('this').toString());
// Output: true
console.info(buf.includes('be').toString());
// Output: false [h2]indexOf
indexOf(value: string | number | FastBuffer | Uint8Array, byteOffset?: number, encoding?: BufferEncoding): number
Obtains the index of the first occurrence of the specified value in this FastBuffer object. If no match is found, -1 is returned.
If byteOffset is a positive number, the offset is calculated from 0. If byteOffset is a negative number, the offset is calculated from the end.
If byteOffset is greater than or equal to this.length, -1 is returned. If byteOffset is less than or equal to -this.length, the index of the first occurrence of the specified value in the FastBuffer is returned.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | number | FastBuffer | Uint8Array | Yes | Content to search. |
| byteOffset | number | No | Number of bytes to skip before starting to check data. If byteOffset is a positive number, the offset is calculated from 0. If byteOffset is a negative number, the offset is calculated from the end. The default value is 0. |
| encoding | BufferEncoding | No | Character encoding format (meaningful only when value is a string). Default value: 'utf8'. Passing an unrecognized encoding throws a TypeError. |
Return value
| Type | Description |
|---|---|
| number | Returns the position of the first occurrence. If value is not contained, -1 is returned. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('this is a buffer');
console.info(buf.indexOf('this').toString());
// Output: 0
console.info(buf.indexOf('is').toString());
// Output: 2 [h2]keys
keys(): IterableIterator<number>
Returns an iterator containing key values, where the key is the byte index position, ranging from 0 to length-1.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| IterableIterator<number> | Iterator created. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('buffer');
let keys = buf.keys();
for (const key of keys) {
console.info(key.toString());
}
/*
Output: 0
1
2
3
4
5
*/ [h2]values
values(): IterableIterator<number>
Returns an iterator containing the byte values of the FastBuffer.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| IterableIterator<number> | Iterator containing the value of each byte in the FastBuffer. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from('buffer');
let valueIterator = buf1.values();
let nextValue:IteratorResult<number> = valueIterator.next();
while (!nextValue.done) {
console.info(nextValue.value.toString());
/*
Output result: 98
117
102
102
101
114
*/
nextValue = valueIterator.next();
} [h2]lastIndexOf
lastIndexOf(value: string | number | FastBuffer | Uint8Array, byteOffset?: number, encoding?: BufferEncoding): number
Obtains the index of the last occurrence of the specified value in this FastBuffer object. If no match is found, -1 is returned.
If byteOffset is a positive number, the offset is calculated from 0. If byteOffset is a negative number, the offset is calculated from the end.
If byteOffset is greater than or equal to this.length, the index of the last occurrence of the specified value in the FastBuffer is returned. If byteOffset is less than or equal to this.length, -1 is returned.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | string | number | FastBuffer | Uint8Array | Yes | Content to search. |
| byteOffset | number | No | Number of bytes to skip before starting to check data. If byteOffset is a positive number, the offset is calculated from 0. If byteOffset is a negative number, the offset is calculated from the end. The default value is this.length - 1. |
| encoding | BufferEncoding | No | Character encoding format (only meaningful when value is a string). Default value: 'utf8'. Passing an unrecognized encoding throws a TypeError. |
Return value
| Type | Description |
|---|---|
| number | Index of the last occurrence of the value. If the object does not contain value, -1 is returned. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('this buffer is a buffer');
console.info(buf.lastIndexOf('this').toString());
// Output: 0
console.info(buf.lastIndexOf('buffer').toString());
// Output: 17 [h2]readBigInt64BE
readBigInt64BE(offset?: number): bigint
Reads a 64-bit, big-endian, signed big integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| bigint | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.info(buf.readBigInt64BE(0).toString());
// Output: 7161960797921896816 [h2]readBigInt64LE
readBigInt64LE(offset?: number): bigint
Reads a 64-bit, little-endian, signed big integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| bigint | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.info(buf.readBigInt64LE(0).toString());
// Output: 8100120198111388771 [h2]readBigUInt64BE
readBigUInt64BE(offset?: number): bigint
Reads a 64-bit, big-endian, unsigned big integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| bigint | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.info(buf.readBigUInt64BE(0).toString());
// Output: 7161960797921896816 [h2]readBigUInt64LE
readBigUInt64LE(offset?: number): bigint
Reads a 64-bit, little-endian, unsigned big integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| bigint | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x70,
0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78]);
console.info(buf.readBigUInt64LE(0).toString());
// Output: 8100120198111388771 [h2]readDoubleBE
readDoubleBE(offset?: number): number
Reads a 64-bit, big-endian, double-precision floating-point number from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.info(buf.readDoubleBE(0).toString());
// Output: 8.20788039913184e-304 [h2]readDoubleLE
readDoubleLE(offset?: number): number
Reads a 64-bit, little-endian, double-precision floating-point number from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.info(buf.readDoubleLE(0).toString());
// Output: 5.447603722011605e-270 [h2]readFloatBE
readFloatBE(offset?: number): number
Reads a 32-bit, big-endian, single-precision floating-point number from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.info(buf.readFloatBE(0).toString());
// Output: 2.387939260590663e-38 [h2]readFloatLE
readFloatLE(offset?: number): number
Reads a 32-bit, little-endian, single-precision floating-point number from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([1, 2, 3, 4, 5, 6, 7, 8]);
console.info(buf.readFloatLE(0).toString());
// Output: 1.539989614439558e-36 [h2]readInt8
readInt8(offset?: number): number
Reads an 8-bit signed integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 1 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 1. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([-1, 5]);
console.info(buf.readInt8(0).toString());
// Output: -1
console.info(buf.readInt8(1).toString());
// Output: 5 [h2]readInt16BE
readInt16BE(offset?: number): number
Reads a 16-bit, big-endian, signed integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 2. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0, 5]);
console.info(buf.readInt16BE(0).toString());
// Output: 5 [h2]readInt16LE
readInt16LE(offset?: number): number
Reads a 16-bit, little-endian, signed integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 2. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0, 5]);
console.info(buf.readInt16LE(0).toString());
// Output: 1280 [h2]readInt32BE
readInt32BE(offset?: number): number
Reads a 32-bit, big-endian, signed integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0, 0, 0, 5]);
console.info(buf.readInt32BE(0).toString());
// Output: 5 [h2]readInt32LE
readInt32LE(offset?: number): number
Reads a 32-bit, little-endian, signed integer from this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0, 0, 0, 5]);
console.info(buf.readInt32LE(0).toString());
// Output: 83886080 [h2]readIntBE
readIntBE(offset: number, byteLength: number): number
Reads the specified number of bytes from this FastBuffer object at the specified offset, and interprets the result as a big-endian, two's complement signed value that supports up to 48 bits of precision.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | Yes | Offset. The default value is 0. Value range: 0 <= offset <= this.length - byteLength |
| byteLength | number | Yes | Number of bytes to read. Value range: 1 <= byteLength <= 6 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from('ab');
let num = buf.readIntBE(0, 1);
console.info(num.toString());
// Output: 97 [h2]readIntLE
readIntLE(offset: number, byteLength: number): number
Reads the specified number of bytes from this FastBuffer object at the specified offset and interprets the result as a little-endian, two's complement signed value that supports up to 48 bits of precision.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | Yes | Offset. The default value is 0. Value range: 0 <= offset <= this.length - byteLength |
| byteLength | number | Yes | Number of bytes to read. Value range: 1 <= byteLength <= 6 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);
console.info(buf.readIntLE(0, 6).toString(16));
// Output: -546f87a9cbee [h2]readUInt8
readUInt8(offset?: number): number
Reads an 8-bit unsigned integer from the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 1 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 1. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([1, -2]);
console.info(buf.readUInt8(0).toString());
// Output: 1
console.info(buf.readUInt8(1).toString());
// Output: 254 [h2]readUInt16BE
readUInt16BE(offset?: number): number
Reads a 16-bit, big-endian, unsigned integer from this FastBuffer object at the specified offset.
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 2. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56]);
console.info(buf.readUInt16BE(0).toString(16));
// Output: 1234
console.info(buf.readUInt16BE(1).toString(16));
// Output: 3456 [h2]readUInt16LE
readUInt16LE(offset?: number): number
Reads an unsigned little-endian 16-bit integer from the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 2. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56]);
console.info(buf.readUInt16LE(0).toString(16));
// Output: 3412
console.info(buf.readUInt16LE(1).toString(16));
// Output: 5634 [h2]readUInt32BE
readUInt32BE(offset?: number): number
Reads an unsigned big-endian 32-bit integer from the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56, 0x78]);
console.info(buf.readUInt32BE(0).toString(16));
// Output: 12345678 [h2]readUInt32LE
readUInt32LE(offset?: number): number
Reads an unsigned, little-endian 32-bit integer from the specified offset.
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Data read. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset]. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56, 0x78]);
console.info(buf.readUInt32LE(0).toString(16));
// Output: 78563412 [h2]readUIntBE
readUIntBE(offset: number, byteLength: number): number
Reads byteLength bytes from the specified offset and interprets the result as an unsigned, big-endian integer with up to 48 bits of precision.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | Yes | Offset. Value range: 0 <= offset <= this.length - byteLength. |
| byteLength | number | Yes | Number of bytes to read. Value range: 1 <= byteLength <= 6. |
Return value
| Type | Description |
|---|---|
| number | Data read. If the offset is a decimal, undefined is returned. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);
console.info(buf.readUIntBE(0, 6).toString(16));
// Output: 1234567890ab [h2]readUIntLE
readUIntLE(offset: number, byteLength: number): number
Reads byteLength bytes from the specified offset and interprets the result as an unsigned, little-endian integer with up to 48 bits of precision.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| offset | number | Yes | Offset. Value range: 0 <= offset <= this.length - byteLength. |
| byteLength | number | Yes | Number of bytes to read. Value range: 1 <= byteLength <= 6 |
Return value
| Type | Description |
|---|---|
| number | Data read. If the offset is a decimal, undefined is returned. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.from([0x12, 0x34, 0x56, 0x78, 0x90, 0xab]);
console.info(buf.readUIntLE(0, 6).toString(16));
// Output: ab9078563412 [h2]subarray
subarray(start?: number, end?: number): FastBuffer
Extracts and returns the data at the specified position of the current object. The returned FastBuffer object shares the same memory area as the original object, and modifying the data of either object affects the other.
System capability: SystemCapability.Utils.Lang
Atomic service API: This API can be used in atomic services since API version 20.
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| start | number | No | Offset to the start position in this FastBuffer object where data is truncated. The default value is 0. |
| end | number | No | End position of the interception (excluding the end position). Default value: byte length of the current object. Value range: start <= end <= this.length. When null is passed in, a FastBuffer object with a length of 0 is returned. |
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object created. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.allocUninitializedFromPool(26);
for (let i = 0; i < 26; i++) {
buf1.writeInt8(i + 97, i);
}
const buf2 = buf1.subarray(0, 3);
console.info(buf2.toString('ascii', 0, buf2.length));
// Output: abc [h2]swap16
swap16(): FastBuffer
Swaps the byte order of the current object in units of 16-bit unsigned integers.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object swapped. |
Error codes
For details about the error codes, see Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200009 | The fastbuffer size must be a multiple of 16-bits. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.info(buf1.toString('hex'));
// Output: 0102030405060708
buf1.swap16();
console.info(buf1.toString('hex'));
// Output: 0201040306050807 [h2]swap32
swap32(): FastBuffer
Converts this FastBuffer object into an array of unsigned 32-bit integers and swaps the byte order in place.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object swapped. |
Error codes
For details about the error codes, see Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200009 | The fastbuffer size must be a multiple of 32-bits. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.info(buf1.toString('hex'));
// Output: 0102030405060708
buf1.swap32();
console.info(buf1.toString('hex'));
// Output: 0403020108070605 [h2]swap64
swap64(): FastBuffer
Converts this FastBuffer object into an array of unsigned 64-bit integers and swaps the byte order in place.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| FastBuffer | FastBuffer object swapped. |
Error codes
For details about the error codes, see Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200009 | The fastbuffer size must be a multiple of 64-bits. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
console.info(buf1.toString('hex'));
// Output: 0102030405060708
buf1.swap64();
console.info(buf1.toString('hex'));
// Output: 0807060504030201 [h2]toJSON
toJSON(): Object
Converts the FastBuffer to JSON and returns it.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Return value
| Type | Description |
|---|---|
| Object | JSON object. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.from([0x1, 0x2, 0x3, 0x4, 0x5]);
let jsonResult = buf1.toJSON();
console.info(JSON.stringify(jsonResult));
// Output: {"type":"FastBuffer","data":[1,2,3,4,5]} [h2]toString
toString(encoding?: string, start?: number, end?: number): string
Converts the data at the specified position in this FastBuffer object into a string in the specified encoding format.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| encoding | string | No | Character encoding format. For the supported format range, see BufferEncoding. Default value: 'utf8'. |
| start | number | No | Offset to the start position of the data to convert. The default value is 0. |
| end | number | No | End position. Default value: this.length. |
Return value
| Type | Description |
|---|---|
| string | String. When the value of start is greater than or equal to this.length or start is greater than end, an empty string is returned. |
Error codes
For details about the error codes, see Universal Error Codes.
| ID | Error Message |
|---|---|
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf1 = fastbuffer.allocUninitializedFromPool(26);
for (let i = 0; i < 26; i++) {
buf1.writeInt8(i + 97, i);
}
console.info(buf1.toString('utf-8'));
// Output: abcdefghijklmnopqrstuvwxyz [h2]write
write(str: string, offset?: number, length?: number, encoding?: string): number
Writes a string in the specified encoding at the offset of the FastBuffer object. The maximum number of bytes written is length, and the actual number of bytes written depends on the number of bytes after the string is encoded.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| str | string | Yes | String to write to the FastBuffer. |
| offset | number | No | Offset. The default value is 0. |
| length | number | No | Maximum number of bytes to write. The default value is this.length - offset. |
| encoding | string | No | Character encoding format. For the supported format range, see BufferEncoding. Default value: 'utf8'. |
Return value
| Type | Description |
|---|---|
| number | Number of bytes written. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | Range error. Possible causes: The value of the parameter is not within the specified range. |
| 10200068 | The underlying ArrayBuffer is null or detach. |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.alloc(256);
let bytesWritten = buf.write('\u00bd + \u00bc = \u00be', 0);
console.info(`${bytesWritten} bytes: ${buf.toString('utf-8', 0, bytesWritten)}`);
// Output: 12 bytes: ½ + ¼ = ¾
let buf1 = fastbuffer.alloc(10);
let length = buf1.write('abcd', 8);
console.info('length = ' + length);
// Output: length = 2 [h2]writeBigInt64BE
writeBigInt64BE(value: bigint, offset?: number): number
Writes a 64-bit, big-endian, signed big integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | bigint | Yes | Data to write to FastBuffer. Value range: -INT64_MAX <= value <= INT64_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeBigInt64BE(BigInt(0x0102030405060708), 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeBigInt64LE
writeBigInt64LE(value: bigint, offset?: number): number
Writes a 64-bit, little-endian, signed big integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | bigint | Yes | Data to write to the FastBuffer. Value range: -INT64_MAX <= value <= INT64_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeBigInt64LE(BigInt(0x0102030405060708), 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeBigUInt64BE
writeBigUInt64BE(value: bigint, offset?: number): number
Writes unsigned, big-endian 64-bit BigUInt data at the offset of the FastBuffer object.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | bigint | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT64_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeBigUInt64BE(BigInt(0xdecafafecacefade), 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeBigUInt64LE
writeBigUInt64LE(value: bigint, offset?: number): number
Writes a 64-bit, little-endian, unsigned big integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | bigint | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT64_MAX. |
| offset | number | No | Offset. Default value: 0. Value range: 0 <= offset <= this.length - 8. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeBigUInt64LE(BigInt(0xdecafafecacefade), 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeDoubleBE
writeDoubleBE(value: number, offset?: number): number
Writes a 64-bit, big-endian, double-precision floating-point number to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -DOUBLE_MAX <= value <= DOUBLE_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeDoubleBE(123.456, 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeDoubleLE
writeDoubleLE(value: number, offset?: number): number
Writes a 64-bit, little-endian, double-precision floating-point number to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -DOUBLE_MAX <= value <= DOUBLE_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 8 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 8. Received value is: [offset] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeDoubleLE(123.456, 0);
console.info('result = ' + result);
// Output: result = 8 [h2]writeFloatBE
writeFloatBE(value: number, offset?: number): number
Writes a 32-bit, big-endian, single-precision floating-point number to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -FLOAT_MAX <= value <= FLOAT_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeFloatBE(3.1415, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeFloatLE
writeFloatLE(value: number, offset?: number): number
Writes a 32-bit, little-endian, single-precision floating-point number to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -FLOAT_MAX <= value <= FLOAT_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "offset" is out of range. It must be >= 0 and <= buf.length - 4. Received value is: [offset] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(8);
let result = buf.writeFloatLE(3.1415, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeInt8
writeInt8(value: number, offset?: number): number
Writes an 8-bit signed integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -INT8_MAX <= value <= INT8_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 1 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(2);
let result = buf.writeInt8(2, 0);
console.info('result = ' + result);
// Output: result = 1
let result1 = buf.writeInt8(-2, 1);
console.info('result1 = ' + result1);
// Output: result1 = 2 [h2]writeInt16BE
writeInt16BE(value: number, offset?: number): number
Writes a 16-bit, big-endian, signed integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -INT16_MAX <= value <= INT16_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(2);
let result = buf.writeInt16BE(0x0102, 0);
console.info('result = ' + result);
// Output: result = 2 [h2]writeInt16LE
writeInt16LE(value: number, offset?: number): number
Writes a 16-bit, little-endian, signed integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -INT16_MAX <= value <= INT16_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(2);
let result = buf.writeInt16LE(0x0304, 0);
console.info('result = ' + result);
// Output: result = 2 [h2]writeInt32BE
writeInt32BE(value: number, offset?: number): number
Writes a 32-bit, big-endian, signed integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -INT32_MAX <= value <= INT32_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeInt32BE(0x01020304, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeInt32LE
writeInt32LE(value: number, offset?: number): number
Writes a 32-bit, little-endian, signed integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -INT32_MAX <= value <= INT32_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeInt32LE(0x05060708, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeIntBE
writeIntBE(value: number, offset: number, byteLength: number): number
Writes a big-endian signed value of the specified length to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -2^(8×byteLength-1) ≤ value ≤ 2^(8×byteLength-1)-1. |
| offset | number | Yes | Offset. Default value: 0. Value range: 0 <= offset <= this.length - byteLength. When null or undefined is passed in, the offset is 0. |
| byteLength | number | Yes | Number of bytes to write. Value range: 1 <= byteLength <= 6. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(6);
let result = buf.writeIntBE(0x1234567890ab, 0, 6);
console.info('result = ' + result);
// Output: result = 6 [h2]writeIntLE
writeIntLE(value: number, offset: number, byteLength: number): number
Writes a little-endian signed value of the specified length to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: -2^(8×byteLength-1) ≤ value ≤ 2^(8×byteLength-1)-1. |
| offset | number | Yes | Offset. Default value: 0. Value range: 0 <= offset <= this.length - byteLength. When null or undefined is passed in, the offset is 0. |
| byteLength | number | Yes | Number of bytes to write. Value range: 1 <= byteLength <= 6. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(6);
let result = buf.writeIntLE(0x1234567890ab, 0, 6);
console.info('result = ' + result);
// Output: result = 6 [h2]writeUInt8
writeUInt8(value: number, offset?: number): number
Writes an 8-bit unsigned integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT8_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 1 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeUInt8(0x3, 0);
console.info('result = ' + result);
// Output: result = 1
let result1 = buf.writeUInt8(0x4, 1);
console.info('result1 = ' + result1);
// Output: result1 = 2
let result2 = buf.writeUInt8(0x23, 2);
console.info('result2 = ' + result2);
// Output: result2 = 3
let result3 = buf.writeUInt8(0x42, 3);
console.info('result3 = ' + result3);
// Output: result3 = 4 [h2]writeUInt16BE
writeUInt16BE(value: number, offset?: number): number
Writes a 16-bit, big-endian, unsigned integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT16_MAX. |
| offset | number | No | Offset. Default value: 0. Value range: 0 <= offset <= this.length - 2. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeUInt16BE(0xdead, 0);
console.info('result = ' + result);
// Output: result = 2
let result1 = buf.writeUInt16BE(0xbeef, 2);
console.info('result1 = ' + result1);
// Output: result1 = 4 [h2]writeUInt16LE
writeUInt16LE(value: number, offset?: number): number
Writes a 16-bit, little-endian, unsigned integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT16_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 2 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeUInt16LE(0xdead, 0);
console.info('result = ' + result);
// Output: result = 2
let result1 = buf.writeUInt16LE(0xbeef, 2);
console.info('result1 = ' + result1);
// Output: result1 = 4 [h2]writeUInt32BE
writeUInt32BE(value: number, offset?: number): number
Writes a 32-bit, big-endian, unsigned integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT32_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeUInt32BE(0xfeedface, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeUInt32LE
writeUInt32LE(value: number, offset?: number): number
Writes a 32-bit, little-endian, unsigned integer to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 <= value <= UINT32_MAX. |
| offset | number | No | Offset. The default value is 0. Value range: 0 <= offset <= this.length - 4 |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(4);
let result = buf.writeUInt32LE(0xfeedface, 0);
console.info('result = ' + result);
// Output: result = 4 [h2]writeUIntBE
writeUIntBE(value: number, offset: number, byteLength: number): number
Writes an unsigned big-endian value of the specified length to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 ≤ value ≤ 2^(8×byteLength)-1. |
| offset | number | Yes | Offset. Default value: 0. Value range: 0 <= offset <= this.length - byteLength. When null or undefined is passed in, the offset is 0. |
| byteLength | number | Yes | Number of bytes to write. Value range: 1 <= byteLength <= 6. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(6);
let result = buf.writeUIntBE(0x1234567890ab, 0, 6);
console.info('result = ' + result);
// Output: result = 6 [h2]writeUIntLE
writeUIntLE(value: number, offset: number, byteLength: number): number
Writes an unsigned little-endian value of the specified length to this FastBuffer object at the specified offset.
Atomic service API: This API can be used in atomic services since API version 20.
System capability: SystemCapability.Utils.Lang
Parameters
| Name | Type | Mandatory | Description |
|---|---|---|---|
| value | number | Yes | Data to write to the FastBuffer. Value range: 0 ≤ value ≤ 2^(8×byteLength)-1. |
| offset | number | Yes | Offset. Default value: 0. Value range: 0 <= offset <= this.length - byteLength. When null or undefined is passed in, the offset is 0. |
| byteLength | number | Yes | Number of bytes to write. Value range: 1 <= byteLength <= 6. |
Return value
| Type | Description |
|---|---|
| number | Offset plus the number of written bytes. |
Error codes
For details about the error codes, see Universal Error Codes and Utils Error Codes.
| ID | Error Message |
|---|---|
| 10200001 | The value of "[param]" is out of range. It must be >= [left range] and <= [right range]. Received value is: [param] |
Example
import { fastbuffer } from '@kit.ArkTS';
let buf = fastbuffer.allocUninitializedFromPool(6);
let result = buf.writeUIntLE(0x1234567890ab, 0, 6);
console.info('result = ' + result);
// Output: result = 6