ElPoyo
46 lines
1.2 KiB
JavaScript
46 lines
1.2 KiB
JavaScript
const encoded = "qospGlrrB";
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function safeDecodePolyline(encoded) {
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let index = 0, len = encoded.length;
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let lat = 0, lng = 0;
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const poly = [];
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while (index < len) {
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let b, shift = 0, result = 0;
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do {
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if (index >= len) break;
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b = encoded.charCodeAt(index++) - 63;
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result |= (b & 0x1f) << shift;
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shift += 5;
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} while (b >= 0x20);
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let dlat = ((result & 1) !== 0 ? ~(result >> 1) : (result >> 1));
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lat += dlat;
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shift = 0;
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result = 0;
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do {
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if (index >= len) break;
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b = encoded.charCodeAt(index++) - 63;
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result |= (b & 0x1f) << shift;
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shift += 5;
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} while (b >= 0x20);
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let dlng = ((result & 1) !== 0 ? ~(result >> 1) : (result >> 1));
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lng += dlng;
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poly.push([lat / 1e5, lng / 1e5]);
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}
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return poly;
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}
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const pts = safeDecodePolyline(encoded);
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console.log("Decoded", pts.length, "points.");
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for(let i=0; i<5 && i<pts.length; i++) {
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console.log(pts[i]);
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}
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if(pts.length > 5) {
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console.log("...");
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for(let i=pts.length-5; i<pts.length; i++) {
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console.log(pts[i]);
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}
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}
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