crypto: refactor ArrayBuffer to bigint conversion utils

aduh95 · targos · commit 573eab9235fa · 2022-12-12T16:17:11.000Z
PR-URL: #45567 Refs: nodejs/performance#16 Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/lib/internal/crypto/random.js b/lib/internal/crypto/random.js
@@ -2,17 +2,22 @@
 
 const {
 Array,
+ ArrayBufferPrototypeGetByteLength,
 ArrayPrototypeForEach,
 ArrayPrototypePush,
 ArrayPrototypeShift,
 ArrayPrototypeSplice,
 BigInt,
+ BigIntPrototypeToString,
+ DataView,
+ DataViewPrototypeGetUint8,
 FunctionPrototypeBind,
 FunctionPrototypeCall,
 MathMin,
 NumberIsNaN,
 NumberIsSafeInteger,
 NumberPrototypeToString,
+ StringFromCharCodeApply,
 StringPrototypePadStart,
 } = primordials;
 
@@ -493,17 +498,39 @@ function generatePrimeSync(size, options = kEmptyObject) {
 return job.result(prime);
 }
 
-function arrayBufferToUnsignedBigInt(arrayBuffer) {
- return BigInt(`0x${Buffer.from(arrayBuffer).toString('hex')}`);
+/**
+ * 48 is the ASCII code for '0', 97 is the ASCII code for 'a'.
+ * @param {number} number An integer between 0 and 15.
+ * @returns {number} corresponding to the ASCII code of the hex representation
+ * of the parameter.
+ */
+const numberToHexCharCode = (number) => (number < 10 ? 48 : 87) + number;
+
+/**
+ * @param {ArrayBuffer} buf An ArrayBuffer.
+ * @return {bigint}
+ */
+function arrayBufferToUnsignedBigInt(buf) {
+ const length = ArrayBufferPrototypeGetByteLength(buf);
+ const chars = Array(length * 2);
+ const view = new DataView(buf);
+
+ for (let i = 0; i < length; i++) {
+ const val = DataViewPrototypeGetUint8(view, i);
+ chars[2 * i] = numberToHexCharCode(val >> 4);
+ chars[2 * i + 1] = numberToHexCharCode(val & 0xf);
+ }
+
+ return BigInt(`0x${StringFromCharCodeApply(chars)}`);
 }
 
 function unsignedBigIntToBuffer(bigint, name) {
 if (bigint < 0) {
 throw new ERR_OUT_OF_RANGE(name, '>= 0', bigint);
 }
 
- const hex = bigint.toString(16);
- const padded = hex.padStart(hex.length + (hex.length % 2), 0);
+ const hex = BigIntPrototypeToString(bigint, 16);
+ const padded = StringPrototypePadStart(hex, hex.length + (hex.length % 2), 0);
 return Buffer.from(padded, 'hex');
 }
 
diff --git a/lib/internal/per_context/primordials.js b/lib/internal/per_context/primordials.js
@@ -45,6 +45,8 @@ const varargsMethods = [
 'MathHypot',
 'MathMax',
 'MathMin',
+ 'StringFromCharCode',
+ 'StringFromCodePoint',
 'StringPrototypeConcat',
 'TypedArrayOf',
 ];
diff --git a/typings/primordials.d.ts b/typings/primordials.d.ts
@@ -422,7 +422,9 @@ declare namespace primordials {
 export const StringName: typeof String.name
 export const StringPrototype: typeof String.prototype
 export const StringFromCharCode: typeof String.fromCharCode
+ export const StringFromCharCodeApply: StaticApply<typeof String.fromCharCode>
 export const StringFromCodePoint: typeof String.fromCodePoint
+ export const StringFromCodePointApply: StaticApply<typeof String.fromCodePoint>
 export const StringRaw: typeof String.raw
 export const StringPrototypeAnchor: UncurryThis<typeof String.prototype.anchor>
 export const StringPrototypeBig: UncurryThis<typeof String.prototype.big>

-Original file line number
+Diff line change
 exportconstStringName: typeofString.name
 exportconstStringPrototype: typeofString.prototype
 exportconstStringFromCharCode: typeofString.fromCharCode
 +exportconstStringFromCharCodeApply: StaticApply<typeofString.fromCharCode>
 exportconstStringFromCodePoint: typeofString.fromCodePoint
 +exportconstStringFromCodePointApply: StaticApply<typeofString.fromCodePoint>
 exportconstStringRaw: typeofString.raw
 exportconstStringPrototypeAnchor: UncurryThis<typeofString.prototype.anchor>
 exportconstStringPrototypeBig: UncurryThis<typeofString.prototype.big>