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denoland-deno/std/node/_buffer.ts

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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import * as hex from "../encoding/hex.ts";
import * as base64 from "../encoding/base64.ts";
import { normalizeEncoding, notImplemented } from "./_utils.ts";
const notImplementedEncodings = [
"ascii",
"binary",
"latin1",
"ucs2",
"utf16le",
];
function checkEncoding(encoding = "utf8", strict = true): string {
if (typeof encoding !== "string" || (strict && encoding === "")) {
if (!strict) return "utf8";
throw new TypeError(`Unkown encoding: ${encoding}`);
}
const normalized = normalizeEncoding(encoding);
if (normalized === undefined) {
throw new TypeError(`Unkown encoding: ${encoding}`);
}
if (notImplementedEncodings.includes(encoding)) {
notImplemented(`"${encoding}" encoding`);
}
return normalized;
}
interface EncodingOp {
byteLength(string: string): number;
}
// https://github.com/nodejs/node/blob/56dbe466fdbc598baea3bfce289bf52b97b8b8f7/lib/buffer.js#L598
const encodingOps: { [key: string]: EncodingOp } = {
utf8: {
byteLength: (string: string): number =>
new TextEncoder().encode(string).byteLength,
},
ucs2: {
byteLength: (string: string): number => string.length * 2,
},
utf16le: {
byteLength: (string: string): number => string.length * 2,
},
latin1: {
byteLength: (string: string): number => string.length,
},
ascii: {
byteLength: (string: string): number => string.length,
},
base64: {
byteLength: (string: string): number =>
base64ByteLength(string, string.length),
},
hex: {
byteLength: (string: string): number => string.length >>> 1,
},
};
function base64ByteLength(str: string, bytes: number): number {
// Handle padding
if (str.charCodeAt(bytes - 1) === 0x3d) bytes--;
if (bytes > 1 && str.charCodeAt(bytes - 1) === 0x3d) bytes--;
// Base64 ratio: 3/4
return (bytes * 3) >>> 2;
}
/**
* See also https://nodejs.org/api/buffer.html
*/
export class Buffer extends Uint8Array {
/**
* Allocates a new Buffer of size bytes.
*/
static alloc(
size: number,
fill?: number | string | Uint8Array | Buffer,
encoding = "utf8",
): Buffer {
if (typeof size !== "number") {
throw new TypeError(
`The "size" argument must be of type number. Received type ${typeof size}`,
);
}
const buf = new Buffer(size);
if (size === 0) return buf;
let bufFill;
if (typeof fill === "string") {
encoding = checkEncoding(encoding);
if (
typeof fill === "string" &&
fill.length === 1 &&
encoding === "utf8"
) {
buf.fill(fill.charCodeAt(0));
} else bufFill = Buffer.from(fill, encoding);
} else if (typeof fill === "number") {
buf.fill(fill);
} else if (fill instanceof Uint8Array) {
if (fill.length === 0) {
throw new TypeError(
`The argument "value" is invalid. Received ${fill.constructor.name} []`,
);
}
bufFill = fill;
}
if (bufFill) {
if (bufFill.length > buf.length) {
bufFill = bufFill.subarray(0, buf.length);
}
let offset = 0;
while (offset < size) {
buf.set(bufFill, offset);
offset += bufFill.length;
if (offset + bufFill.length >= size) break;
}
if (offset !== size) {
buf.set(bufFill.subarray(0, size - offset), offset);
}
}
return buf;
}
static allocUnsafe(size: number): Buffer {
return new Buffer(size);
}
/**
* Returns the byte length of a string when encoded. This is not the same as
* String.prototype.length, which does not account for the encoding that is
* used to convert the string into bytes.
*/
static byteLength(
string: string | Buffer | ArrayBufferView | ArrayBuffer | SharedArrayBuffer,
encoding = "utf8",
): number {
if (typeof string != "string") return string.byteLength;
encoding = normalizeEncoding(encoding) || "utf8";
return encodingOps[encoding].byteLength(string);
}
/**
* Returns a new Buffer which is the result of concatenating all the Buffer
* instances in the list together.
*/
static concat(list: Buffer[] | Uint8Array[], totalLength?: number): Buffer {
if (totalLength == undefined) {
totalLength = 0;
for (const buf of list) {
totalLength += buf.length;
}
}
const buffer = Buffer.allocUnsafe(totalLength);
let pos = 0;
for (const item of list) {
let buf: Buffer;
if (!(item instanceof Buffer)) {
buf = Buffer.from(item);
} else {
buf = item;
}
buf.copy(buffer, pos);
pos += buf.length;
}
return buffer;
}
/**
* Allocates a new Buffer using an array of bytes in the range 0 255. Array
* entries outside that range will be truncated to fit into it.
*/
static from(array: number[]): Buffer;
/**
* This creates a view of the ArrayBuffer without copying the underlying
* memory. For example, when passed a reference to the .buffer property of a
* TypedArray instance, the newly created Buffer will share the same allocated
* memory as the TypedArray.
*/
static from(
arrayBuffer: ArrayBuffer | SharedArrayBuffer,
byteOffset?: number,
length?: number,
): Buffer;
/**
* Copies the passed buffer data onto a new Buffer instance.
*/
static from(buffer: Buffer | Uint8Array): Buffer;
/**
* Creates a new Buffer containing string.
*/
static from(string: string, encoding?: string): Buffer;
static from(
// deno-lint-ignore no-explicit-any
value: any,
offsetOrEncoding?: number | string,
length?: number,
): Buffer {
const offset = typeof offsetOrEncoding === "string"
? undefined
: offsetOrEncoding;
let encoding = typeof offsetOrEncoding === "string"
? offsetOrEncoding
: undefined;
if (typeof value == "string") {
encoding = checkEncoding(encoding, false);
if (encoding === "hex") return new Buffer(hex.decodeString(value).buffer);
if (encoding === "base64") return new Buffer(base64.decode(value).buffer);
return new Buffer(new TextEncoder().encode(value).buffer);
}
// workaround for https://github.com/microsoft/TypeScript/issues/38446
return new Buffer(value, offset!, length);
}
/**
* Returns true if obj is a Buffer, false otherwise.
*/
static isBuffer(obj: unknown): obj is Buffer {
return obj instanceof Buffer;
}
// deno-lint-ignore no-explicit-any
static isEncoding(encoding: any): boolean {
return (
typeof encoding === "string" &&
encoding.length !== 0 &&
normalizeEncoding(encoding) !== undefined
);
}
/**
* Copies data from a region of buf to a region in target, even if the target
* memory region overlaps with buf.
*/
copy(
targetBuffer: Buffer | Uint8Array,
targetStart = 0,
sourceStart = 0,
sourceEnd = this.length,
): number {
const sourceBuffer = this
.subarray(sourceStart, sourceEnd)
.subarray(0, Math.max(0, targetBuffer.length - targetStart));
if (sourceBuffer.length === 0) return 0;
targetBuffer.set(sourceBuffer, targetStart);
return sourceBuffer.length;
}
/*
* Returns true if both buf and otherBuffer have exactly the same bytes, false otherwise.
*/
equals(otherBuffer: Uint8Array | Buffer): boolean {
if (!(otherBuffer instanceof Uint8Array)) {
throw new TypeError(
`The "otherBuffer" argument must be an instance of Buffer or Uint8Array. Received type ${typeof otherBuffer}`,
);
}
if (this === otherBuffer) return true;
if (this.byteLength !== otherBuffer.byteLength) return false;
for (let i = 0; i < this.length; i++) {
if (this[i] !== otherBuffer[i]) return false;
}
return true;
}
readBigInt64BE(offset = 0): bigint {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getBigInt64(offset);
}
readBigInt64LE(offset = 0): bigint {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getBigInt64(offset, true);
}
readBigUInt64BE(offset = 0): bigint {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getBigUint64(offset);
}
readBigUInt64LE(offset = 0): bigint {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getBigUint64(offset, true);
}
readDoubleBE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getFloat64(offset);
}
readDoubleLE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getFloat64(offset, true);
}
readFloatBE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getFloat32(offset);
}
readFloatLE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getFloat32(offset, true);
}
readInt8(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getInt8(
offset,
);
}
readInt16BE(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getInt16(
offset,
);
}
readInt16LE(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getInt16(
offset,
true,
);
}
readInt32BE(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getInt32(
offset,
);
}
readInt32LE(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getInt32(
offset,
true,
);
}
readUInt8(offset = 0): number {
return new DataView(this.buffer, this.byteOffset, this.byteLength).getUint8(
offset,
);
}
readUInt16BE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getUint16(offset);
}
readUInt16LE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getUint16(offset, true);
}
readUInt32BE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getUint32(offset);
}
readUInt32LE(offset = 0): number {
return new DataView(
this.buffer,
this.byteOffset,
this.byteLength,
).getUint32(offset, true);
}
/**
* Returns a new Buffer that references the same memory as the original, but
* offset and cropped by the start and end indices.
*/
slice(begin = 0, end = this.length): Buffer {
// workaround for https://github.com/microsoft/TypeScript/issues/38665
return this.subarray(begin, end) as Buffer;
}
/**
* Returns a JSON representation of buf. JSON.stringify() implicitly calls
* this function when stringifying a Buffer instance.
*/
toJSON(): Record<string, unknown> {
return { type: "Buffer", data: Array.from(this) };
}
/**
* Decodes buf to a string according to the specified character encoding in
* encoding. start and end may be passed to decode only a subset of buf.
*/
toString(encoding = "utf8", start = 0, end = this.length): string {
encoding = checkEncoding(encoding);
const b = this.subarray(start, end);
if (encoding === "hex") return hex.encodeToString(b);
if (encoding === "base64") return base64.encode(b.buffer);
return new TextDecoder(encoding).decode(b);
}
/**
* Writes string to buf at offset according to the character encoding in
* encoding. The length parameter is the number of bytes to write. If buf did
* not contain enough space to fit the entire string, only part of string will
* be written. However, partially encoded characters will not be written.
*/
write(string: string, offset = 0, length = this.length): number {
return new TextEncoder().encodeInto(
string,
this.subarray(offset, offset + length),
).written;
}
writeBigInt64BE(value: bigint, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setBigInt64(
offset,
value,
);
return offset + 4;
}
writeBigInt64LE(value: bigint, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setBigInt64(
offset,
value,
true,
);
return offset + 4;
}
writeBigUInt64BE(value: bigint, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setBigUint64(
offset,
value,
);
return offset + 4;
}
writeBigUInt64LE(value: bigint, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setBigUint64(
offset,
value,
true,
);
return offset + 4;
}
writeDoubleBE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setFloat64(
offset,
value,
);
return offset + 8;
}
writeDoubleLE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setFloat64(
offset,
value,
true,
);
return offset + 8;
}
writeFloatBE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setFloat32(
offset,
value,
);
return offset + 4;
}
writeFloatLE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setFloat32(
offset,
value,
true,
);
return offset + 4;
}
writeInt8(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setInt8(
offset,
value,
);
return offset + 1;
}
writeInt16BE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setInt16(
offset,
value,
);
return offset + 2;
}
writeInt16LE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setInt16(
offset,
value,
true,
);
return offset + 2;
}
writeInt32BE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint32(
offset,
value,
);
return offset + 4;
}
writeInt32LE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setInt32(
offset,
value,
true,
);
return offset + 4;
}
writeUInt8(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint8(
offset,
value,
);
return offset + 1;
}
writeUInt16BE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint16(
offset,
value,
);
return offset + 2;
}
writeUInt16LE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint16(
offset,
value,
true,
);
return offset + 2;
}
writeUInt32BE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint32(
offset,
value,
);
return offset + 4;
}
writeUInt32LE(value: number, offset = 0): number {
new DataView(this.buffer, this.byteOffset, this.byteLength).setUint32(
offset,
value,
true,
);
return offset + 4;
}
}