51 lines
1.7 KiB
JavaScript
51 lines
1.7 KiB
JavaScript
/**
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* Find the starting index of Uint8Array `b` within Uint8Array `a`.
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*/ export function indexOfUint8Array(a, b) {
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if (b.length === 0) return 0;
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if (a.length === 0 || b.length > a.length) return -1;
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// start iterating through `a`
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for(let i = 0; i <= a.length - b.length; i++){
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let completeMatch = true;
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// from index `i`, iterate through `b` and check for mismatch
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for(let j = 0; j < b.length; j++){
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// if the values do not match, then this isn't a complete match, exit `b` iteration early and iterate to next index of `a`.
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if (a[i + j] !== b[j]) {
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completeMatch = false;
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break;
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}
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}
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if (completeMatch) {
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return i;
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}
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}
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return -1;
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}
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/**
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* Check if two Uint8Arrays are strictly equivalent.
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*/ export function isEquivalentUint8Arrays(a, b) {
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if (a.length !== b.length) return false;
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for(let i = 0; i < a.length; i++){
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if (a[i] !== b[i]) return false;
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}
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return true;
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}
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/**
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* Remove Uint8Array `b` from Uint8Array `a`.
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*
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* If `b` is not in `a`, `a` is returned unchanged.
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*
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* Otherwise, the function returns a new Uint8Array instance with size `a.length - b.length`
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*/ export function removeFromUint8Array(a, b) {
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const tagIndex = indexOfUint8Array(a, b);
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if (tagIndex === 0) return a.subarray(b.length);
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if (tagIndex > -1) {
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const removed = new Uint8Array(a.length - b.length);
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removed.set(a.slice(0, tagIndex));
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removed.set(a.slice(tagIndex + b.length), tagIndex);
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return removed;
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} else {
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return a;
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}
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}
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//# sourceMappingURL=uint8array-helpers.js.map
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