@stringsync/vexml
Version:
MusicXML to Vexflow
205 lines (204 loc) • 8.78 kB
JavaScript
;
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o["default"] = v;
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var __importStar = (this && this.__importStar) || (function () {
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Object.defineProperty(exports, "__esModule", { value: true });
exports.MeasureSequenceIterator = void 0;
const util = __importStar(require("../util"));
/**
* A class that iterates over measures in playback order (accounting for repeats and jumps).
*/
class MeasureSequenceIterator {
measures;
constructor(measures) {
this.measures = measures;
}
[Symbol.iterator]() {
const repeats = Repeat.from(this.measures);
const activeRepeats = new util.Stack();
function getState() {
const activeRepeat = activeRepeats.peek();
const measureRepeats = repeats.filter((repeat) => repeat.to === measureIndex);
let measureRepeatIndex = measureRepeats.findIndex((repeat) => activeRepeat?.matches(repeat));
measureRepeatIndex = measureRepeatIndex === -1 ? 0 : measureRepeatIndex;
const measureRepeat = measureRepeats.at(measureRepeatIndex);
const nextMeasureRepeat = measureRepeats.at(measureRepeatIndex + 1);
return { activeRepeat, measureRepeat, nextMeasureRepeat };
}
let measureIndex = 0;
const iterator = {
next: () => {
// We've reached the end of the measures.
if (measureIndex >= this.measures.length) {
return { value: null, done: true };
}
const measure = this.measures[measureIndex];
const { activeRepeat, measureRepeat, nextMeasureRepeat } = getState();
const isMeasureExcluded = activeRepeat?.isMeasureExcluded(measureIndex);
if (isMeasureExcluded) {
measureIndex++;
return iterator.next();
}
const isMeasureRepeatActive = measureRepeat && activeRepeat && measureRepeat.matches(activeRepeat);
// The measure repeat is active, has finished, and there is another repeat to process.
if (isMeasureRepeatActive && activeRepeat.isFinished() && nextMeasureRepeat) {
activeRepeats.pop();
const nextActiveRepeat = nextMeasureRepeat.clone();
activeRepeats.push(nextActiveRepeat);
nextActiveRepeat.decrement();
measureIndex = nextMeasureRepeat.from;
return { value: measure.index, done: false };
}
// The measure repeat is active, has finished, and there is not another repeat to process.
if (isMeasureRepeatActive && activeRepeat.isFinished() && !nextMeasureRepeat) {
activeRepeats.pop();
measureIndex++;
return { value: measure.index, done: false };
}
// The measure repeat is active and has not finished.
if (isMeasureRepeatActive && !activeRepeat.isFinished()) {
activeRepeat.decrement();
measureIndex = activeRepeat.from;
return { value: measure.index, done: false };
}
// The measure repeat is not active, but it should be.
if (measureRepeat && !measureRepeat.matches(activeRepeat)) {
const nextActiveRepeat = measureRepeat.clone();
activeRepeats.push(nextActiveRepeat);
nextActiveRepeat.decrement();
measureIndex = measureRepeat.from;
return { value: measure.index, done: false };
}
// Nothing special to do with this measure, move forward.
measureIndex++;
return { value: measure.index, done: false };
},
};
return iterator;
}
}
exports.MeasureSequenceIterator = MeasureSequenceIterator;
/** A class that conveniently wraps repeat metadata. */
class Repeat {
from;
to;
id;
times;
excluding;
constructor(opts) {
this.from = opts.from;
this.to = opts.to;
this.id = opts.id;
this.times = opts.times;
this.excluding = opts.excluding;
}
static from(measures) {
const result = new Array();
let nextId = 1;
const startMeasureIndexes = new util.Stack();
for (let measureIndex = 0; measureIndex < measures.length; measureIndex++) {
const measure = measures[measureIndex];
const hasRepeatEnding = measure.jumps.some((jump) => jump.type === 'repeatending');
for (const jump of measure.jumps) {
if (jump.type === 'repeatstart') {
startMeasureIndexes.push(measureIndex);
}
// We only process repeatends if there is no repeatending in the same measure.
if (!hasRepeatEnding && jump.type === 'repeatend') {
// Not all repeatends have a corresponding repeatstart. Assume they're supposed to repeat from the beginning.
const startMeasureIndex = startMeasureIndexes.pop() ?? 0;
result.push(new Repeat({
id: nextId++,
times: jump.times,
from: startMeasureIndex,
to: measureIndex,
excluding: [],
}));
}
if (jump.type === 'repeatending' && jump.times > 0) {
// Not all repeatendings have a corresponding repeatstart. Assume they're supposed to repeat from the
// beginning.
const startMeasureIndex = startMeasureIndexes.pop() ?? 0;
if (jump.times > 1) {
result.push(new Repeat({
id: nextId++,
times: jump.times - 1,
from: startMeasureIndex,
to: measureIndex,
excluding: [],
}));
}
// Exclude all the previous repeatendings.
const excluding = new Array();
let i = measureIndex;
while (i > startMeasureIndex && measures[i].jumps.some((jump) => jump.type === 'repeatending')) {
excluding.push(i);
i--;
}
result.push(new Repeat({
id: nextId++,
times: 1,
from: startMeasureIndex,
to: measureIndex,
excluding,
}));
}
}
}
return result;
}
matches(repeat) {
return this.id === repeat?.id;
}
isMeasureExcluded(measureIndex) {
return this.excluding.includes(measureIndex);
}
isFinished() {
return this.times === 0;
}
decrement() {
if (this.times === 0) {
throw new Error('Cannot decrement a repeat that has already been exhausted.');
}
this.times--;
}
clone() {
return new Repeat({
id: this.id,
times: this.times,
from: this.from,
to: this.to,
excluding: [...this.excluding],
});
}
}