| 1 | /*
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| 2 | MIT License http://www.opensource.org/licenses/mit-license.php
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| 3 | Author Tobias Koppers @sokra
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| 4 | */
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| 5 |
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| 6 | "use strict";
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| 7 |
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| 8 | const ALPHABET =
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| 9 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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| 10 |
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| 11 | const CONTINUATION_BIT = 0x20;
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| 12 | const END_SEGMENT_BIT = 0x40;
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| 13 | const NEXT_LINE = END_SEGMENT_BIT | 0x01;
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| 14 | const INVALID = END_SEGMENT_BIT | 0x02;
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| 15 | const DATA_MASK = 0x1f;
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| 16 |
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| 17 | const ccToValue = new Uint8Array("z".charCodeAt(0) + 1);
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| 18 |
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| 19 | ccToValue.fill(INVALID);
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| 20 |
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| 21 | for (let i = 0; i < ALPHABET.length; i++) {
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| 22 | ccToValue[ALPHABET.charCodeAt(i)] = i;
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| 23 | }
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| 24 |
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| 25 | ccToValue[",".charCodeAt(0)] = END_SEGMENT_BIT;
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| 26 | ccToValue[";".charCodeAt(0)] = NEXT_LINE;
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| 27 |
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| 28 | const ccMax = ccToValue.length - 1;
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| 29 |
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| 30 | /** @typedef {(generatedLine: number, generatedColumn: number, sourceIndex: number, originalLine: number, originalColumn: number, nameIndex: number) => void} OnMapping */
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| 31 |
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| 32 | /**
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| 33 | * @param {string} mappings the mappings string
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| 34 | * @param {OnMapping} onMapping called for each mapping
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| 35 | * @returns {void}
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| 36 | */
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| 37 | const readMappings = (mappings, onMapping) => {
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| 38 | // generatedColumn, [sourceIndex, originalLine, originalColumn, [nameIndex]]
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| 39 | const currentData = new Int32Array([0, 0, 1, 0, 0]);
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| 40 | let currentDataPos = 0;
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| 41 | // currentValue will include a sign bit at bit 0
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| 42 | let currentValue = 0;
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| 43 | let currentValuePos = 0;
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| 44 | let generatedLine = 1;
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| 45 | let generatedColumn = -1;
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| 46 | for (let i = 0; i < mappings.length; i++) {
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| 47 | const cc = mappings.charCodeAt(i);
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| 48 | if (cc > ccMax) continue;
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| 49 | const value = ccToValue[cc];
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| 50 | if ((value & END_SEGMENT_BIT) !== 0) {
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| 51 | // End current segment
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| 52 | if (currentData[0] > generatedColumn) {
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| 53 | if (currentDataPos === 1) {
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| 54 | onMapping(generatedLine, currentData[0], -1, -1, -1, -1);
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| 55 | } else if (currentDataPos === 4) {
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| 56 | onMapping(
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| 57 | generatedLine,
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| 58 | currentData[0],
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| 59 | currentData[1],
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| 60 | currentData[2],
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| 61 | currentData[3],
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| 62 | -1,
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| 63 | );
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| 64 | } else if (currentDataPos === 5) {
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| 65 | onMapping(
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| 66 | generatedLine,
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| 67 | currentData[0],
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| 68 | currentData[1],
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| 69 | currentData[2],
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| 70 | currentData[3],
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| 71 | currentData[4],
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| 72 | );
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| 73 | }
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| 74 | // Direct typed-array index is faster here than destructuring,
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| 75 | // which would invoke the Int32Array iterator protocol.
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| 76 | // eslint-disable-next-line prefer-destructuring
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| 77 | generatedColumn = currentData[0];
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| 78 | }
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| 79 | currentDataPos = 0;
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| 80 | if (value === NEXT_LINE) {
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| 81 | // Start new line
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| 82 | generatedLine++;
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| 83 | currentData[0] = 0;
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| 84 | generatedColumn = -1;
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| 85 | }
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| 86 | } else if ((value & CONTINUATION_BIT) === 0) {
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| 87 | // last sextet
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| 88 | currentValue |= value << currentValuePos;
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| 89 | const finalValue =
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| 90 | currentValue & 1 ? -(currentValue >> 1) : currentValue >> 1;
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| 91 | currentData[currentDataPos++] += finalValue;
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| 92 | currentValuePos = 0;
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| 93 | currentValue = 0;
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| 94 | } else {
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| 95 | currentValue |= (value & DATA_MASK) << currentValuePos;
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| 96 | currentValuePos += 5;
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| 97 | }
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| 98 | }
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| 99 | // End current segment
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| 100 | if (currentDataPos === 1) {
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| 101 | onMapping(generatedLine, currentData[0], -1, -1, -1, -1);
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| 102 | } else if (currentDataPos === 4) {
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| 103 | onMapping(
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| 104 | generatedLine,
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| 105 | currentData[0],
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| 106 | currentData[1],
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| 107 | currentData[2],
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| 108 | currentData[3],
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| 109 | -1,
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| 110 | );
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| 111 | } else if (currentDataPos === 5) {
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| 112 | onMapping(
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| 113 | generatedLine,
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| 114 | currentData[0],
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| 115 | currentData[1],
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| 116 | currentData[2],
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| 117 | currentData[3],
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| 118 | currentData[4],
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| 119 | );
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| 120 | }
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| 121 | };
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| 122 |
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| 123 | module.exports = readMappings;
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