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https://github.com/morluto/rea
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Dragolone
48e7470041
The hex carrier trimmed outer ASCII whitespace with a global start|end-anchored regex. For an invalid carrier with a long interior whitespace run, the end branch was retried at every position of the run, so rejection took quadratic time (about 18 s for a 200 KB run) and a few hundred KB could exhaust the worker deadline instead of returning the documented invalid-format error. Trim with index scans over the same ASCII whitespace set. Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>
35 lines
1.4 KiB
TypeScript
35 lines
1.4 KiB
TypeScript
/** Expected carrier encoding failure, independent of the analysis engine. */
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export class EvmCarrierFailure extends Error {}
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/** Outer ASCII whitespace only; BOM and other Unicode spaces stay invalid. */
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const asciiWhitespace = (code: number): boolean =>
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code === 0x20 || (code >= 0x09 && code <= 0x0d);
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/** Decode only the explicitly selected representation; source carrier bytes are retained separately. */
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export const decodeEvmBytecodeCarrier = (
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bytes: Uint8Array,
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encoding: "raw" | "hex",
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): Uint8Array => {
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if (encoding === "raw") return Uint8Array.from(bytes);
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let text: string;
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try {
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text = new TextDecoder("utf-8", { fatal: true, ignoreBOM: true }).decode(
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bytes,
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);
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} catch (cause: unknown) {
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throw new EvmCarrierFailure("Hex carrier must be valid UTF-8.", { cause });
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}
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// Index scans keep trimming linear; a global start|end regex backtracks
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// through every interior whitespace run.
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let start = 0;
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let end = text.length;
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while (start < end && asciiWhitespace(text.charCodeAt(start))) start += 1;
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while (end > start && asciiWhitespace(text.charCodeAt(end - 1))) end -= 1;
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const code = text.slice(start, end).replace(/^0x/i, "");
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if (!/^(?:[a-fA-F0-9]{2})*$/.test(code))
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throw new EvmCarrierFailure(
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"Hex carrier requires complete hexadecimal byte pairs, an optional 0x prefix and outer ASCII whitespace; interior separators are invalid.",
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);
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return Uint8Array.from(Buffer.from(code, "hex"));
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};
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