226 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			226 lines
		
	
	
		
			5.5 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| /*
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| 	MIT License http://www.opensource.org/licenses/mit-license.php
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| 	Author Tobias Koppers @sokra
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| */
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| 
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| "use strict";
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| 
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| /**
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|  * @callback MappingsSerializer
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|  * @param {number} generatedLine generated line
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|  * @param {number} generatedColumn generated column
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|  * @param {number} sourceIndex source index
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|  * @param {number} originalLine original line
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|  * @param {number} originalColumn generated line
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|  * @param {number} nameIndex generated line
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|  * @returns {string} result
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|  */
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| 
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| const ALPHABET = [
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| 	..."ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
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| ];
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| 
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| const CONTINUATION_BIT = 0x20;
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| 
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| const createFullMappingsSerializer = () => {
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| 	let currentLine = 1;
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| 	let currentColumn = 0;
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| 	let currentSourceIndex = 0;
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| 	let currentOriginalLine = 1;
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| 	let currentOriginalColumn = 0;
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| 	let currentNameIndex = 0;
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| 	let activeMapping = false;
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| 	let activeName = false;
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| 	let initial = true;
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| 	/** @type {MappingsSerializer} */
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| 	return (
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| 		generatedLine,
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| 		generatedColumn,
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| 		sourceIndex,
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| 		originalLine,
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| 		originalColumn,
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| 		nameIndex,
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| 	) => {
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| 		if (activeMapping && currentLine === generatedLine) {
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| 			// A mapping is still active
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| 			if (
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| 				sourceIndex === currentSourceIndex &&
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| 				originalLine === currentOriginalLine &&
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| 				originalColumn === currentOriginalColumn &&
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| 				!activeName &&
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| 				nameIndex < 0
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| 			) {
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| 				// avoid repeating the same original mapping
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| 				return "";
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| 			}
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| 		}
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| 		// No mapping is active
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| 		else if (sourceIndex < 0) {
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| 			// avoid writing unneccessary generated mappings
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| 			return "";
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| 		}
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| 
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| 		/** @type {undefined | string} */
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| 		let str;
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| 		if (currentLine < generatedLine) {
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| 			str = ";".repeat(generatedLine - currentLine);
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| 			currentLine = generatedLine;
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| 			currentColumn = 0;
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| 			initial = false;
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| 		} else if (initial) {
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| 			str = "";
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| 			initial = false;
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| 		} else {
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| 			str = ",";
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| 		}
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| 
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| 		/**
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| 		 * @param {number} value value
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| 		 * @returns {void}
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| 		 */
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| 		const writeValue = (value) => {
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| 			const sign = (value >>> 31) & 1;
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| 			const mask = value >> 31;
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| 			const absValue = (value + mask) ^ mask;
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| 			let data = (absValue << 1) | sign;
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| 			for (;;) {
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| 				const sextet = data & 0x1f;
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| 				data >>= 5;
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| 				if (data === 0) {
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| 					str += ALPHABET[sextet];
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| 					break;
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| 				} else {
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| 					str += ALPHABET[sextet | CONTINUATION_BIT];
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| 				}
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| 			}
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| 		};
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| 		writeValue(generatedColumn - currentColumn);
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| 		currentColumn = generatedColumn;
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| 		if (sourceIndex >= 0) {
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| 			activeMapping = true;
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| 			if (sourceIndex === currentSourceIndex) {
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| 				str += "A";
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| 			} else {
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| 				writeValue(sourceIndex - currentSourceIndex);
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| 				currentSourceIndex = sourceIndex;
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| 			}
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| 			writeValue(originalLine - currentOriginalLine);
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| 			currentOriginalLine = originalLine;
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| 			if (originalColumn === currentOriginalColumn) {
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| 				str += "A";
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| 			} else {
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| 				writeValue(originalColumn - currentOriginalColumn);
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| 				currentOriginalColumn = originalColumn;
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| 			}
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| 			if (nameIndex >= 0) {
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| 				writeValue(nameIndex - currentNameIndex);
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| 				currentNameIndex = nameIndex;
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| 				activeName = true;
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| 			} else {
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| 				activeName = false;
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| 			}
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| 		} else {
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| 			activeMapping = false;
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| 		}
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| 		return str;
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| 	};
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| };
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| 
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| const createLinesOnlyMappingsSerializer = () => {
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| 	let lastWrittenLine = 0;
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| 	let currentLine = 1;
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| 	let currentSourceIndex = 0;
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| 	let currentOriginalLine = 1;
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| 	/** @type {MappingsSerializer} */
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| 	return (
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| 		generatedLine,
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| 		_generatedColumn,
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| 		sourceIndex,
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| 		originalLine,
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| 		_originalColumn,
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| 		_nameIndex,
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| 	) => {
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| 		if (sourceIndex < 0) {
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| 			// avoid writing generated mappings at all
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| 			return "";
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| 		}
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| 		if (lastWrittenLine === generatedLine) {
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| 			// avoid writing multiple original mappings per line
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| 			return "";
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| 		}
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| 		/** @type {undefined | string} */
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| 		let str;
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| 		/**
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| 		 * @param {number} value value
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| 		 * @returns {void}
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| 		 */
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| 		const writeValue = (value) => {
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| 			const sign = (value >>> 31) & 1;
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| 			const mask = value >> 31;
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| 			const absValue = (value + mask) ^ mask;
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| 			let data = (absValue << 1) | sign;
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| 			for (;;) {
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| 				const sextet = data & 0x1f;
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| 				data >>= 5;
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| 				if (data === 0) {
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| 					str += ALPHABET[sextet];
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| 					break;
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| 				} else {
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| 					str += ALPHABET[sextet | CONTINUATION_BIT];
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| 				}
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| 			}
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| 		};
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| 		lastWrittenLine = generatedLine;
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| 		if (generatedLine === currentLine + 1) {
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| 			currentLine = generatedLine;
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| 			if (sourceIndex === currentSourceIndex) {
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| 				if (originalLine === currentOriginalLine + 1) {
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| 					currentOriginalLine = originalLine;
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| 					return ";AACA";
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| 				}
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| 				str = ";AA";
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| 				writeValue(originalLine - currentOriginalLine);
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| 				currentOriginalLine = originalLine;
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| 				return `${str}A`;
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| 			}
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| 			str = ";A";
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| 			writeValue(sourceIndex - currentSourceIndex);
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| 			currentSourceIndex = sourceIndex;
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| 			writeValue(originalLine - currentOriginalLine);
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| 			currentOriginalLine = originalLine;
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| 			return `${str}A`;
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| 		}
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| 		str = ";".repeat(generatedLine - currentLine);
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| 		currentLine = generatedLine;
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| 		if (sourceIndex === currentSourceIndex) {
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| 			if (originalLine === currentOriginalLine + 1) {
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| 				currentOriginalLine = originalLine;
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| 				return `${str}AACA`;
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| 			}
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| 			str += "AA";
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| 			writeValue(originalLine - currentOriginalLine);
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| 			currentOriginalLine = originalLine;
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| 			return `${str}A`;
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| 		}
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| 		str += "A";
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| 		writeValue(sourceIndex - currentSourceIndex);
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| 		currentSourceIndex = sourceIndex;
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| 		writeValue(originalLine - currentOriginalLine);
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| 		currentOriginalLine = originalLine;
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| 		return `${str}A`;
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| 	};
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| };
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| 
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| /**
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|  * @param {{ columns?: boolean }=} options options
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|  * @returns {MappingsSerializer} mappings serializer
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|  */
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| const createMappingsSerializer = (options) => {
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| 	const linesOnly = options && options.columns === false;
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| 	return linesOnly
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| 		? createLinesOnlyMappingsSerializer()
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| 		: createFullMappingsSerializer();
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| };
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| 
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| module.exports = createMappingsSerializer;
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