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buffer: make methods work on Uint8Array instances
Removes the reliance on prototype bound methods internally so that Uint8Arrays can be set as the bound `this` value when calling the various Buffer methods. Introduces some additional tamper protection by removing internal reliance on writable properties. Fixes: #56577 PR-URL: #56578 Reviewed-By: Anna Henningsen <anna@addaleax.net>
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‎doc/api/buffer.md‎

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@@ -415,6 +415,21 @@ function:
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* [`Buffer.from(arrayBuffer[, byteOffset[, length]])`][`Buffer.from(arrayBuf)`]
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* [`Buffer.from(string[, encoding])`][`Buffer.from(string)`]
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### Buffer methods are callable with `Uint8Array` instances
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All methods on the Buffer prototype are callable with a `Uint8Array` instance.
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```js
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const { toString, write } = Buffer.prototype;
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const uint8array = new Uint8Array(5);
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write.call(uint8array, 'hello', 0, 5, 'utf8'); // 5
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// <Uint8Array 68 65 6c 6c 6f>
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toString.call(uint8array, 'utf8'); // 'hello'
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```
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## Buffers and iteration
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`Buffer` instances can be iterated over using `for..of` syntax:
@@ -2058,6 +2073,10 @@ console.log(buf.fill('zz', 'hex'));
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<!-- YAML
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added: v5.3.0
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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-->
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* `value` {string|Buffer|Uint8Array|integer} What to search for.
@@ -2945,10 +2964,14 @@ console.log(buf.readInt32LE(1));
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<!-- YAML
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added: v0.11.15
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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- version: v10.0.0
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pr-url: https://github.com/nodejs/node/pull/18395
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description: Removed `noAssert` and no implicit coercion of the offset
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and `byteLength` to `uint32` anymore.
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-->
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* `offset` {integer} Number of bytes to skip before starting to read. Must
@@ -2992,10 +3015,14 @@ console.log(buf.readIntBE(1, 0).toString(16));
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<!-- YAML
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added: v0.11.15
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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- version: v10.0.0
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pr-url: https://github.com/nodejs/node/pull/18395
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description: Removed `noAssert` and no implicit coercion of the offset
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and `byteLength` to `uint32` anymore.
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-->
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* `offset` {integer} Number of bytes to skip before starting to read. Must
@@ -3269,6 +3296,9 @@ console.log(buf.readUInt32LE(1).toString(16));
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<!-- YAML
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added: v0.11.15
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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- version:
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- v14.9.0
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- v12.19.0
@@ -3319,6 +3349,9 @@ console.log(buf.readUIntBE(1, 6).toString(16));
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<!-- YAML
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added: v0.11.15
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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- version:
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- v14.9.0
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- v12.19.0
@@ -3771,6 +3804,10 @@ console.log(copy);
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<!-- YAML
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added: v0.1.90
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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-->
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* `encoding` {string} The character encoding to use. **Default:** `'utf8'`.
@@ -3909,6 +3946,10 @@ for (const value of buf) {
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<!-- YAML
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added: v0.1.90
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changes:
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- version: REPLACEME
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pr-url: https://github.com/nodejs/node/pull/56578
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description: supports Uint8Array as `this` value.
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-->
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* `string` {string} String to write to `buf`.

‎lib/buffer.js‎

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@@ -72,6 +72,17 @@ const {
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kStringMaxLength,
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atob: _atob,
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btoa: _btoa,
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asciiSlice,
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base64Slice,
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base64urlSlice,
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latin1Slice,
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hexSlice,
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ucs2Slice,
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utf8Slice,
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base64Write,
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base64urlWrite,
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hexWrite,
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ucs2Write,
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} = internalBinding('buffer');
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const {
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constants: {
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markAsUntransferable,
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addBufferPrototypeMethods,
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createUnsafeBuffer,
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asciiWrite,
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latin1Write,
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utf8Write,
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} = require('internal/buffer');
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FastBuffer.prototype.constructor = Buffer;
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encoding: 'utf8',
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encodingVal: encodingsMap.utf8,
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byteLength: byteLengthUtf8,
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write: (buf, string, offset, len) => buf.utf8Write(string, offset, len),
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slice: (buf, start, end) => buf.utf8Slice(start, end),
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write: utf8Write,
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slice: utf8Slice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfString(buf, val, byteOffset, encodingsMap.utf8, dir),
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},
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ucs2: {
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encoding: 'ucs2',
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encodingVal: encodingsMap.utf16le,
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byteLength: (string) => string.length * 2,
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write: (buf, string, offset, len) => buf.ucs2Write(string, offset, len),
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slice: (buf, start, end) => buf.ucs2Slice(start, end),
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write: ucs2Write,
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slice: ucs2Slice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfString(buf, val, byteOffset, encodingsMap.utf16le, dir),
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},
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utf16le: {
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encoding: 'utf16le',
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encodingVal: encodingsMap.utf16le,
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byteLength: (string) => string.length * 2,
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write: (buf, string, offset, len) => buf.ucs2Write(string, offset, len),
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slice: (buf, start, end) => buf.ucs2Slice(start, end),
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write: ucs2Write,
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slice: ucs2Slice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfString(buf, val, byteOffset, encodingsMap.utf16le, dir),
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},
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latin1: {
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encoding: 'latin1',
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encodingVal: encodingsMap.latin1,
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byteLength: (string) => string.length,
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write: (buf, string, offset, len) => buf.latin1Write(string, offset, len),
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slice: (buf, start, end) => buf.latin1Slice(start, end),
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write: latin1Write,
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slice: latin1Slice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfString(buf, val, byteOffset, encodingsMap.latin1, dir),
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},
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ascii: {
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encoding: 'ascii',
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encodingVal: encodingsMap.ascii,
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byteLength: (string) => string.length,
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write: (buf, string, offset, len) => buf.asciiWrite(string, offset, len),
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slice: (buf, start, end) => buf.asciiSlice(start, end),
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write: asciiWrite,
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slice: asciiSlice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfBuffer(buf,
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fromStringFast(val, encodingOps.ascii),
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encoding: 'base64',
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encodingVal: encodingsMap.base64,
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byteLength: (string) => base64ByteLength(string, string.length),
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write: (buf, string, offset, len) => buf.base64Write(string, offset, len),
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slice: (buf, start, end) => buf.base64Slice(start, end),
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write: base64Write,
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slice: base64Slice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfBuffer(buf,
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fromStringFast(val, encodingOps.base64),
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encoding: 'base64url',
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encodingVal: encodingsMap.base64url,
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byteLength: (string) => base64ByteLength(string, string.length),
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write: (buf, string, offset, len) =>
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buf.base64urlWrite(string, offset, len),
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slice: (buf, start, end) => buf.base64urlSlice(start, end),
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write: base64urlWrite,
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slice: base64urlSlice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfBuffer(buf,
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fromStringFast(val, encodingOps.base64url),
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encoding: 'hex',
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encodingVal: encodingsMap.hex,
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byteLength: (string) => string.length >>> 1,
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write: (buf, string, offset, len) => buf.hexWrite(string, offset, len),
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slice: (buf, start, end) => buf.hexSlice(start, end),
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write: hexWrite,
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slice: hexSlice,
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indexOf: (buf, val, byteOffset, dir) =>
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indexOfBuffer(buf,
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fromStringFast(val, encodingOps.hex),
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// to their upper/lower bounds if the value passed is out of range.
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Buffer.prototype.toString = function toString(encoding, start, end) {
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if (arguments.length === 0) {
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return this.utf8Slice(0, this.length);
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return utf8Slice(this, 0, this.length);
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}
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const len = this.length;
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return '';
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if (encoding === undefined)
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return this.utf8Slice(start, end);
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return utf8Slice(this, start, end);
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const ops = getEncodingOps(encoding);
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if (ops === undefined)
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const actualMax = MathMin(max, this.length);
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const remaining = this.length - max;
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let str = StringPrototypeTrim(RegExpPrototypeSymbolReplace(
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/(.{2})/g, this.hexSlice(0, actualMax), '$1 '));
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/(.{2})/g, hexSlice(this, 0, actualMax), '$1 '));
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if (remaining > 0)
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str += ` ... ${remaining} more byte${remaining > 1 ? 's' : ''}`;
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// Inspect special properties as well, if possible.
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Buffer.prototype.includes = function includes(val, byteOffset, encoding) {
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return this.indexOf(val, byteOffset, encoding) !== -1;
1043+
return bidirectionalIndexOf(this, val, byteOffset, encoding, true) !== -1;
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};
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// Usage:
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11121125
Buffer.prototype.write = function write(string, offset, length, encoding) {
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// Buffer#write(string);
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if (offset === undefined) {
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return this.utf8Write(string, 0, this.length);
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return utf8Write(this, string, 0, this.length);
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}
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// Buffer#write(string, encoding)
11181131
if (length === undefined && typeof offset === 'string') {
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}
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if (!encoding || encoding === 'utf8')
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return this.utf8Write(string, offset, length);
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return utf8Write(this, string, offset, length);
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if (encoding === 'ascii')
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return this.asciiWrite(string, offset, length);
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return asciiWrite(this, string, offset, length);
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const ops = getEncodingOps(encoding);
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if (ops === undefined)

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