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fix Fletcher-32/64 Checksum

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* Operate on words, not bytes
* Add tests
This commit is contained in:
MikeCAT 2022-11-02 21:54:45 +09:00
parent ed8bd34915
commit 5b134d7e9e
5 changed files with 137 additions and 8 deletions
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14
src/core/operations/Fletcher32Checksum.mjs
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@ -35,10 +35,18 @@ class Fletcher32Checksum extends Operation {
run(input, args) {
let a = 0,
b = 0;
input = new Uint8Array(input);
if (ArrayBuffer.isView(input)) {
input = new DataView(input.buffer, input.byteOffset, input.byteLength);
} else {
input = new DataView(input);
}
for (let i = 0; i < input.length; i++) {
a = (a + input[i]) % 0xffff;
for (let i = 0; i < input.byteLength - 1; i += 2) {
a = (a + input.getUint16(i, true)) % 0xffff;
b = (b + a) % 0xffff;
}
if (input.byteLength % 2 !== 0) {
a = (a + input.getUint8(input.byteLength - 1)) % 0xffff;
b = (b + a) % 0xffff;
}