Class StringSource

src/v6/inputSource/StringSource.js:4–121

export default class StringSource{
  constructor(str){
    this.line = 1;
    this.cols = 0;
    this.buffer = str;
    //a boundary pointer to indicate where from the buffer dat should be read
    // data before this pointer can be deleted to free the memory
    this.startIndex = 0;
  }

  readCh() {
    return this.buffer[this.startIndex++];
  }

  readChAt(index) {
    return this.buffer[this.startIndex+index];
  }

  readStr(n,from){
    if(typeof from === "undefined") from = this.startIndex;
    return this.buffer.substring(from, from + n);
  }

  readUpto(stopStr) {
    const inputLength = this.buffer.length;
    const stopLength = stopStr.length;

    for (let i = this.startIndex; i < inputLength; i++) {
      let match = true;
      for (let j = 0; j < stopLength; j++) {
        if (this.buffer[i + j] !== stopStr[j]) {
          match = false;
          break;
        }
      }

      if (match) {
        const result = this.buffer.substring(this.startIndex, i);
        this.startIndex = i + stopLength;
        return result;
      }
    }

    throw new Error(`Unexpected end of source. Reading '${stopStr}'`);
  }

  readUptoCloseTag(stopStr) { //stopStr: "</tagname"
    const inputLength = this.buffer.length;
    const stopLength = stopStr.length;
    let stopIndex = 0;
    //0: non-matching, 1: matching stop string, 2: matching closing
    let match = 0;

    for (let i = this.startIndex; i < inputLength; i++) {
      if(match === 1){//initial part matched
        if(stopIndex === 0) stopIndex = i;
        if(this.buffer[i] === ' ' || this.buffer[i] === '\t') continue;
        else if(this.buffer[i] === '>'){