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import {Interval} from './Interval.js';
const MAX_CHAR_CODE = 0xffff;
export class InputStream {  constructor(source) {    this.source = source;    this.pos = 0;    this.examinedLength = 0;  }
  atEnd() {    const ans = this.pos >= this.source.length;    this.examinedLength = Math.max(this.examinedLength, this.pos + 1);    return ans;  }
  next() {    const ans = this.source[this.pos++];    this.examinedLength = Math.max(this.examinedLength, this.pos);    return ans;  }
  nextCharCode() {    const nextChar = this.next();    return nextChar && nextChar.charCodeAt(0);  }
  nextCodePoint() {    const cp = this.source.slice(this.pos++).codePointAt(0);    // If the code point is beyond plane 0, it takes up two characters.    if (cp > MAX_CHAR_CODE) {      this.pos += 1;    }    this.examinedLength = Math.max(this.examinedLength, this.pos);    return cp;  }
  matchString(s, optIgnoreCase) {    let idx;    if (optIgnoreCase) {      /*        Case-insensitive comparison is a tricky business. Some notable gotchas include the        "Turkish I" problem (http://www.i18nguy.com/unicode/turkish-i18n.html) and the fact        that the German Esszet (ß) turns into "SS" in upper case.
        This is intended to be a locale-invariant comparison, which means it may not obey        locale-specific expectations (e.g. "i" => "İ").       */      for (idx = 0; idx < s.length; idx++) {        const actual = this.next();        const expected = s[idx];        if (actual == null || actual.toUpperCase() !== expected.toUpperCase()) {          return false;        }      }      return true;    }    // Default is case-sensitive comparison.    for (idx = 0; idx < s.length; idx++) {      if (this.next() !== s[idx]) {        return false;      }    }    return true;  }
  sourceSlice(startIdx, endIdx) {    return this.source.slice(startIdx, endIdx);  }
  interval(startIdx, optEndIdx) {    return new Interval(this.source, startIdx, optEndIdx ? optEndIdx : this.pos);  }}