import QRCode from "qrcode";
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function u32(buf: Uint8Array, offset: number, value: number) {
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buf[offset] = (value >>> 24) & 255;
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buf[offset + 1] = (value >>> 16) & 255;
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buf[offset + 2] = (value >>> 8) & 255;
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buf[offset + 3] = value & 255;
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}
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function crc32(data: Uint8Array) {
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let c = 0xffffffff;
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for (let i = 0; i < data.length; i++) {
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c ^= data[i];
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for (let k = 0; k < 8; k++) {
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c = (c >>> 1) ^ (c & 1 ? 0xedb88320 : 0);
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}
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}
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return (c ^ 0xffffffff) >>> 0;
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}
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function adler32(data: Uint8Array) {
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let a = 1;
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let b = 0;
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for (let i = 0; i < data.length; i++) {
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a = (a + data[i]) % 65521;
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b = (b + a) % 65521;
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}
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return ((b << 16) | a) >>> 0;
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}
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function chunk(type: string, data: Uint8Array) {
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const out = new Uint8Array(12 + data.length);
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u32(out, 0, data.length);
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out[4] = type.charCodeAt(0);
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out[5] = type.charCodeAt(1);
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out[6] = type.charCodeAt(2);
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out[7] = type.charCodeAt(3);
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out.set(data, 8);
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u32(out, 8 + data.length, crc32(out.subarray(4, 8 + data.length)));
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return out;
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}
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function concat(parts: Uint8Array[]) {
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const len = parts.reduce((sum, part) => sum + part.length, 0);
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const out = new Uint8Array(len);
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let offset = 0;
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for (const part of parts) {
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out.set(part, offset);
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offset += part.length;
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}
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return out;
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}
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function zlibStore(raw: Uint8Array) {
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const blocks: Uint8Array[] = [];
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let offset = 0;
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while (offset < raw.length) {
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const len = Math.min(65535, raw.length - offset);
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const last = offset + len >= raw.length;
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const block = new Uint8Array(5 + len);
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block[0] = last ? 1 : 0;
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block[1] = len & 255;
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block[2] = (len >>> 8) & 255;
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const nlen = (~len) & 0xffff;
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block[3] = nlen & 255;
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block[4] = (nlen >>> 8) & 255;
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block.set(raw.subarray(offset, offset + len), 5);
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blocks.push(block);
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offset += len;
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}
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const bodyLen = blocks.reduce((sum, block) => sum + block.length, 0);
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const out = new Uint8Array(2 + bodyLen + 4);
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out[0] = 0x78;
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out[1] = 0x01;
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let cursor = 2;
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for (const block of blocks) {
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out.set(block, cursor);
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cursor += block.length;
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}
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u32(out, cursor, adler32(raw));
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return out;
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}
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function bytesToBase64(bytes: Uint8Array) {
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const api = typeof uni === "undefined" ? undefined : uni;
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if (api && typeof api.arrayBufferToBase64 === "function") {
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const buffer = bytes.buffer.slice(bytes.byteOffset, bytes.byteOffset + bytes.byteLength);
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return api.arrayBufferToBase64(buffer as ArrayBuffer);
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}
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const table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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let out = "";
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for (let i = 0; i < bytes.length; i += 3) {
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const a = bytes[i];
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const b = i + 1 < bytes.length ? bytes[i + 1] : 0;
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const c = i + 2 < bytes.length ? bytes[i + 2] : 0;
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const n = (a << 16) | (b << 8) | c;
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out += table[(n >> 18) & 63];
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out += table[(n >> 12) & 63];
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out += i + 1 < bytes.length ? table[(n >> 6) & 63] : "=";
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out += i + 2 < bytes.length ? table[n & 63] : "=";
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}
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return out;
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}
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/** 不依赖浏览器 canvas，直接画出可在小程序 image 中显示的 PNG。 */
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export function createQrPng(text: string) {
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const qr = QRCode.create(text, { errorCorrectionLevel: "M" });
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const modules = qr.modules;
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const count = modules.size;
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const margin = 4;
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const scale = 8;
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const size = (count + margin * 2) * scale;
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const raw = new Uint8Array(size * (size + 1));
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let cursor = 0;
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for (let y = 0; y < size; y++) {
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raw[cursor++] = 0;
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const row = Math.floor(y / scale) - margin;
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for (let x = 0; x < size; x++) {
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const col = Math.floor(x / scale) - margin;
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const dark =
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row >= 0 && col >= 0 && row < count && col < count && !!modules.get(row, col);
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raw[cursor++] = dark ? 0 : 255;
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}
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}
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const ihdr = new Uint8Array(13);
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u32(ihdr, 0, size);
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u32(ihdr, 4, size);
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ihdr[8] = 8;
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const signature = Uint8Array.from([137, 80, 78, 71, 13, 10, 26, 10]);
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return concat([
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signature,
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chunk("IHDR", ihdr),
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chunk("IDAT", zlibStore(raw)),
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chunk("IEND", new Uint8Array(0)),
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]);
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}
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function fileName(text: string) {
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let hash = 0;
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for (let i = 0; i < text.length; i++) {
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hash = (hash * 31 + text.charCodeAt(i)) >>> 0;
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}
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return hash.toString(16);
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}
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function savePng(bytes: Uint8Array, text: string) {
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const base64 = bytesToBase64(bytes);
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const dataUrl = `data:image/png;base64,${base64}`;
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const root = (globalThis as any).wx?.env?.USER_DATA_PATH;
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if (!root || typeof uni === "undefined" || typeof uni.getFileSystemManager !== "function") {
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return Promise.resolve(dataUrl);
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}
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const filePath = `${root}/recycle-qr-${fileName(text)}.png`;
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return new Promise<string>((resolve) => {
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uni.getFileSystemManager().writeFile({
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filePath,
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data: base64,
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encoding: "base64",
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success: () => resolve(filePath),
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fail: () => resolve(dataUrl),
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});
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});
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}
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export function generateQrcode(text: string) {
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return savePng(createQrPng(text), text);
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}
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export function generateRecycleQrcode(text: string) {
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return generateQrcode(text);
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}
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/**
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* 清除指定二维码缓存
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* @param key
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*/
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export function clearQrcodeCache(key: string) {
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uni.removeStorageSync(key);
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}
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