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perf(cbor): for encoding numbers, bigints, and dates #6214

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merged 3 commits into from
Nov 28, 2024
+32 −13
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perf(cbor): for encoding numbers, bigints, and dates #6214

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a4bf59d
perf(cbor): for encoding numbers, bigints, and dates
BlackAsLight Nov 27, 2024
4eefb79
revert(cbor): smaller number encoding
BlackAsLight Nov 27, 2024
f5707e0
Merge branch 'main' into cbor_performance
BlackAsLight Nov 28, 2024
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45 changes: 32 additions & 13 deletions cbor/_common_encode.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -12,35 +12,51 @@ export function encodeNumber(x: number): Uint8Array {
const majorType = isNegative ? 0b001_00000 : 0b000_00000;
if (isNegative) x = -x - 1;

if (x < 24) return new Uint8Array([majorType + x]);
if (x < 2 ** 8) return new Uint8Array([majorType + 24, x]);
if (x < 24) return Uint8Array.from([majorType + x]);
if (x < 2 ** 8) return Uint8Array.from([majorType + 24, x]);
const output = new Uint8Array(9);
const view = new DataView(output.buffer);
if (x < 2 ** 16) {
return concat([new Uint8Array([majorType + 25]), numberToArray(2, x)]);
output[0] = majorType + 25;
view.setUint16(1, x);
return output.subarray(0, 3);
}
if (x < 2 ** 32) {
return concat([new Uint8Array([majorType + 26]), numberToArray(4, x)]);
output[0] = majorType + 26;
view.setUint32(1, x);
return output.subarray(0, 5);
}
if (x < 2 ** 64) {
output[0] = majorType + 27;
// Due to possible precision loss with numbers this large, it's best to do conversion under BigInt or end up with 1n off.
return encodeBigInt(BigInt(isNegative ? -x - 1 : x));
view.setBigUint64(1, BigInt(x));
return output;
}
throw new RangeError(
`Cannot encode number: It (${isNegative ? -x - 1 : x}) exceeds ${
isNegative ? "-" : ""
}2 ** 64 - 1`,
);
}
return concat([new Uint8Array([0b111_11011]), numberToArray(8, x)]);
const output = new Uint8Array(9);
const view = new DataView(output.buffer);
output[0] = 0b111_11011;
view.setFloat64(1, x);
return output;
}

export function encodeBigInt(x: bigint): Uint8Array {
const isNegative = x < 0n;
if ((isNegative ? -x : x) < 2n ** 32n) return encodeNumber(Number(x));

const head = new Uint8Array([x < 0n ? 0b001_11011 : 0b000_11011]);
const output = new Uint8Array(9);
const view = new DataView(output.buffer);
if (isNegative) x = -x - 1n;

if (x < 2n ** 64n) return concat([head, numberToArray(8, x)]);
if (x < 2n ** 64n) {
output[0] = isNegative ? 0b001_11011 : 0b000_11011;
view.setBigUint64(1, x);
return output;
}
throw new RangeError(
`Cannot encode bigint: It (${isNegative ? -x - 1n : x}) exceeds ${
isNegative ? "-" : ""
Expand Down Expand Up @@ -84,10 +100,13 @@ export function encodeString(x: string): Uint8Array {
}

export function encodeDate(x: Date): Uint8Array {
return concat([
new Uint8Array([0b110_00001]),
encodeNumber(x.getTime() / 1000),
]);
const input = encodeNumber(x.getTime() / 1000);
// deno-lint-ignore no-explicit-any
const output = new Uint8Array((input.buffer as any)
.transfer(input.length + 1));
output.set(output.subarray(0, -1), 1);
output[0] = 0b110_00001;
return output;
}

export function encodeArray(x: CborType[]): Uint8Array {
Expand Down