SharifandClaude Sonnet 5.5
1a9b726354
Up to 50 images at once; single-image flow unchanged. Includes a dependency-free stored-ZIP writer. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
91 lines
2.7 KiB
JavaScript
91 lines
2.7 KiB
JavaScript
/**
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* Minimal ZIP writer (stored, no compression). Images are already compressed,
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* so deflating them gains nothing, and this avoids a dependency.
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*/
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const CRC_TABLE = (() => {
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const table = new Uint32Array(256);
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for (let n = 0; n < 256; n++) {
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let c = n;
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for (let k = 0; k < 8; k++) c = c & 1 ? 0xedb88320 ^ (c >>> 1) : c >>> 1;
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table[n] = c >>> 0;
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}
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return table;
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})();
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function crc32(bytes) {
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let crc = 0xffffffff;
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for (let i = 0; i < bytes.length; i++) {
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crc = CRC_TABLE[(crc ^ bytes[i]) & 0xff] ^ (crc >>> 8);
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}
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return (crc ^ 0xffffffff) >>> 0;
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}
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function header(size, write) {
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const view = new DataView(new ArrayBuffer(size));
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write(view);
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return new Uint8Array(view.buffer);
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}
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/** @param {{name: string, data: Uint8Array}[]} files @returns {Blob} */
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export function createZip(files) {
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const encoder = new TextEncoder();
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const now = new Date();
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const time = (now.getHours() << 11) | (now.getMinutes() << 5) | (now.getSeconds() >> 1);
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const date = ((now.getFullYear() - 1980) << 9) | ((now.getMonth() + 1) << 5) | now.getDate();
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const parts = [];
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const central = [];
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let offset = 0;
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for (const { name, data } of files) {
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const nameBytes = encoder.encode(name);
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const crc = crc32(data);
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const local = header(30, (v) => {
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v.setUint32(0, 0x04034b50, true);
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v.setUint16(4, 20, true);
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v.setUint16(6, 0x0800, true); // UTF-8 names
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v.setUint16(8, 0, true); // stored
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v.setUint16(10, time, true);
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v.setUint16(12, date, true);
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v.setUint32(14, crc, true);
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v.setUint32(18, data.length, true);
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v.setUint32(22, data.length, true);
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v.setUint16(26, nameBytes.length, true);
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});
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parts.push(local, nameBytes, data);
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central.push(
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header(46, (v) => {
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v.setUint32(0, 0x02014b50, true);
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v.setUint16(4, 20, true);
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v.setUint16(6, 20, true);
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v.setUint16(8, 0x0800, true);
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v.setUint16(10, 0, true);
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v.setUint16(12, time, true);
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v.setUint16(14, date, true);
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v.setUint32(16, crc, true);
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v.setUint32(20, data.length, true);
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v.setUint32(24, data.length, true);
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v.setUint16(28, nameBytes.length, true);
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v.setUint32(42, offset, true);
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}),
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nameBytes
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);
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offset += local.length + nameBytes.length + data.length;
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}
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const centralSize = central.reduce((sum, part) => sum + part.length, 0);
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const end = header(22, (v) => {
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v.setUint32(0, 0x06054b50, true);
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v.setUint16(8, files.length, true);
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v.setUint16(10, files.length, true);
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v.setUint32(12, centralSize, true);
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v.setUint32(16, offset, true);
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});
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return new Blob([...parts, ...central, end], { type: "application/zip" });
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}
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