26 lines
726 B
Plaintext
26 lines
726 B
Plaintext
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import { readUInt32BE, findBox } from "./utils.js";
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const JP2 = {
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validate(input) {
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if (readUInt32BE(input, 4) !== 1783636e3 || readUInt32BE(input, 0) < 1)
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return false;
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const ftypBox = findBox(input, "ftyp", 0);
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if (!ftypBox)
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return false;
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return readUInt32BE(input, ftypBox.offset + 4) === 1718909296;
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},
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calculate(input) {
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const jp2hBox = findBox(input, "jp2h", 0);
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const ihdrBox = jp2hBox && findBox(input, "ihdr", jp2hBox.offset + 8);
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if (ihdrBox) {
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return {
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height: readUInt32BE(input, ihdrBox.offset + 8),
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width: readUInt32BE(input, ihdrBox.offset + 12)
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};
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}
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throw new TypeError("Unsupported JPEG 2000 format");
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}
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};
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export {
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JP2
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};
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