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build/node_modules/exif-parser/lib/simplify.js

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+var exif = require('./exif');
+var date = require('./date');
+
+var degreeTags = [{
+	section: exif.GPSIFD,
+	type: 0x0002,
+	name: 'GPSLatitude',
+	refType: 0x0001,
+	refName: 'GPSLatitudeRef',
+	posVal: 'N'
+},
+{
+	section: exif.GPSIFD,
+	type: 0x0004,
+	name: 'GPSLongitude',
+	refType: 0x0003,
+	refName: 'GPSLongitudeRef',
+	posVal: 'E'
+}];
+var dateTags = [{
+	section: exif.SubIFD,
+	type: 0x0132,
+	name: 'ModifyDate'
+},
+{
+	section: exif.SubIFD,
+	type: 0x9003,
+	name: 'DateTimeOriginal'
+},
+{
+	section: exif.SubIFD,
+	type: 0x9004,
+	name: 'CreateDate'
+},
+{
+	section: exif.SubIFD,
+	type: 0x0132,
+	name : 'ModifyDate',
+}];
+
+module.exports = {
+	castDegreeValues: function(getTagValue, setTagValue) {
+		degreeTags.forEach(function(t) {
+			var degreeVal = getTagValue(t);
+			if(degreeVal) {
+				var degreeRef = getTagValue({section: t.section, type: t.refType, name: t.refName});
+				var degreeNumRef = degreeRef === t.posVal ? 1 : -1;
+				var degree = (degreeVal[0] + (degreeVal[1] / 60) + (degreeVal[2] / 3600)) * degreeNumRef;
+				setTagValue(t, degree);
+			}
+		});
+	},
+	castDateValues: function(getTagValue, setTagValue) {
+		dateTags.forEach(function(t) {
+			var dateStrVal = getTagValue(t);
+			if(dateStrVal) {
+				//some easy checks to determine two common date formats
+				var timestamp = date.parseExifDate(dateStrVal);
+				if(typeof timestamp !== 'undefined') {
+					setTagValue(t, timestamp);
+				}
+			}
+		});
+	},
+	simplifyValue: function(values, format) {
+		if(Array.isArray(values)) {
+			values = values.map(function(value) {
+				if(format === 10 || format === 5) {
+					return value[0] / value[1];
+				}
+				return value;
+			});
+			if(values.length === 1) {
+				values = values[0];
+			}
+		}
+		return values;
+	}
+};