pdfjs-dist/lib/core/xfa/formcalc_lexer.js

/**
 * @licstart The following is the entire license notice for the
 * JavaScript code in this page
 *
 * Copyright 2022 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * JavaScript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Token = exports.TOKEN = exports.Lexer = void 0;
const KEYWORDS = new Set(["and", "break", "continue", "do", "downto", "else", "elseif", "end", "endfor", "endfunc", "endif", "endwhile", "eq", "exit", "for", "foreach", "func", "ge", "gt", "if", "in", "infinity", "le", "lt", "nan", "ne", "not", "null", "or", "return", "step", "then", "this", "throw", "upto", "var", "while"]);
const TOKEN = {
  and: 0,
  divide: 1,
  dot: 2,
  dotDot: 3,
  dotHash: 4,
  dotStar: 5,
  eq: 6,
  ge: 7,
  gt: 8,
  le: 9,
  leftBracket: 10,
  leftParen: 11,
  lt: 12,
  minus: 13,
  ne: 14,
  not: 15,
  null: 16,
  number: 17,
  or: 18,
  plus: 19,
  rightBracket: 20,
  rightParen: 21,
  string: 22,
  this: 23,
  times: 24,
  identifier: 25,
  break: 26,
  continue: 27,
  do: 28,
  for: 29,
  foreach: 30,
  func: 31,
  if: 32,
  var: 33,
  while: 34,
  assign: 35,
  comma: 36,
  downto: 37,
  else: 38,
  elseif: 39,
  end: 40,
  endif: 41,
  endfor: 42,
  endfunc: 43,
  endwhile: 44,
  eof: 45,
  exit: 46,
  in: 47,
  infinity: 48,
  nan: 49,
  return: 50,
  step: 51,
  then: 52,
  throw: 53,
  upto: 54
};
exports.TOKEN = TOKEN;
const hexPattern = /^[uU]([0-9a-fA-F]{4,8})/;
const numberPattern = /^\d*(?:\.\d*)?(?:[Ee][+-]?\d+)?/;
const dotNumberPattern = /^\d*(?:[Ee][+-]?\d+)?/;
const eolPattern = /[\r\n]+/;
const identifierPattern = new RegExp("^[\\p{L}_$!][\\p{L}\\p{N}_$]*", "u");
class Token {
  constructor(id, value = null) {
    this.id = id;
    this.value = value;
  }
}
exports.Token = Token;
const Singletons = function () {
  const obj = Object.create(null);
  const nonSingleton = new Set(["identifier", "string", "number", "nan", "infinity"]);
  for (const [name, id] of Object.entries(TOKEN)) {
    if (!nonSingleton.has(name)) {
      obj[name] = new Token(id);
    }
  }
  obj.nan = new Token(TOKEN.number, NaN);
  obj.infinity = new Token(TOKEN.number, Infinity);
  return obj;
}();
class Lexer {
  constructor(data) {
    this.data = data;
    this.pos = 0;
    this.len = data.length;
    this.strBuf = [];
  }
  skipUntilEOL() {
    const match = this.data.slice(this.pos).match(eolPattern);
    if (match) {
      this.pos += match.index + match[0].length;
    } else {
      this.pos = this.len;
    }
  }
  getIdentifier() {
    this.pos--;
    const match = this.data.slice(this.pos).match(identifierPattern);
    if (!match) {
      throw new Error(`Invalid token in FormCalc expression at position ${this.pos}.`);
    }
    const identifier = this.data.slice(this.pos, this.pos + match[0].length);
    this.pos += match[0].length;
    const lower = identifier.toLowerCase();
    if (!KEYWORDS.has(lower)) {
      return new Token(TOKEN.identifier, identifier);
    }
    return Singletons[lower];
  }
  getString() {
    const str = this.strBuf;
    const data = this.data;
    let start = this.pos;
    while (this.pos < this.len) {
      const char = data.charCodeAt(this.pos++);
      if (char === 0x22) {
        if (data.charCodeAt(this.pos) === 0x22) {
          str.push(data.slice(start, this.pos++));
          start = this.pos;
          continue;
        }
        break;
      }
      if (char === 0x5c) {
        const match = data.substring(this.pos, this.pos + 10).match(hexPattern);
        if (!match) {
          continue;
        }
        str.push(data.slice(start, this.pos - 1));
        const code = match[1];
        if (code.length === 4) {
          str.push(String.fromCharCode(parseInt(code, 16)));
          start = this.pos += 5;
        } else if (code.length !== 8) {
          str.push(String.fromCharCode(parseInt(code.slice(0, 4), 16)));
          start = this.pos += 5;
        } else {
          str.push(String.fromCharCode(parseInt(code, 16)));
          start = this.pos += 9;
        }
      }
    }
    const lastChunk = data.slice(start, this.pos - 1);
    if (str.length === 0) {
      return new Token(TOKEN.string, lastChunk);
    }
    str.push(lastChunk);
    const string = str.join("");
    str.length = 0;
    return new Token(TOKEN.string, string);
  }
  getNumber(first) {
    const match = this.data.substring(this.pos).match(numberPattern);
    if (!match[0]) {
      return new Token(TOKEN.number, first - 0x30);
    }
    const number = parseFloat(this.data.substring(this.pos - 1, this.pos + match[0].length));
    this.pos += match[0].length;
    return new Token(TOKEN.number, number);
  }
  getCompOperator(alt1, alt2) {
    if (this.data.charCodeAt(this.pos) === 0x3d) {
      this.pos++;
      return alt1;
    }
    return alt2;
  }
  getLower() {
    const char = this.data.charCodeAt(this.pos);
    if (char === 0x3d) {
      this.pos++;
      return Singletons.le;
    }
    if (char === 0x3e) {
      this.pos++;
      return Singletons.ne;
    }
    return Singletons.lt;
  }
  getSlash() {
    if (this.data.charCodeAt(this.pos) === 0x2f) {
      this.skipUntilEOL();
      return false;
    }
    return true;
  }
  getDot() {
    const char = this.data.charCodeAt(this.pos);
    if (char === 0x2e) {
      this.pos++;
      return Singletons.dotDot;
    }
    if (char === 0x2a) {
      this.pos++;
      return Singletons.dotStar;
    }
    if (char === 0x23) {
      this.pos++;
      return Singletons.dotHash;
    }
    if (0x30 <= char && char <= 0x39) {
      this.pos++;
      const match = this.data.substring(this.pos).match(dotNumberPattern);
      if (!match) {
        return new Token(TOKEN.number, (char - 0x30) / 10);
      }
      const end = this.pos + match[0].length;
      const number = parseFloat(this.data.substring(this.pos - 2, end));
      this.pos = end;
      return new Token(TOKEN.number, number);
    }
    return Singletons.dot;
  }
  next() {
    while (this.pos < this.len) {
      const char = this.data.charCodeAt(this.pos++);
      switch (char) {
        case 0x09:
        case 0x0a:
        case 0x0b:
        case 0x0c:
        case 0x0d:
        case 0x20:
          break;
        case 0x22:
          return this.getString();
        case 0x26:
          return Singletons.and;
        case 0x28:
          return Singletons.leftParen;
        case 0x29:
          return Singletons.rightParen;
        case 0x2a:
          return Singletons.times;
        case 0x2b:
          return Singletons.plus;
        case 0x2c:
          return Singletons.comma;
        case 0x2d:
          return Singletons.minus;
        case 0x2e:
          return this.getDot();
        case 0x2f:
          if (this.getSlash()) {
            return Singletons.divide;
          }
          break;
        case 0x30:
        case 0x31:
        case 0x32:
        case 0x33:
        case 0x34:
        case 0x35:
        case 0x36:
        case 0x37:
        case 0x38:
        case 0x39:
          return this.getNumber(char);
        case 0x3b:
          this.skipUntilEOL();
          break;
        case 0x3c:
          return this.getLower();
        case 0x3d:
          return this.getCompOperator(Singletons.eq, Singletons.assign);
        case 0x3e:
          return this.getCompOperator(Singletons.ge, Singletons.gt);
        case 0x5b:
          return Singletons.leftBracket;
        case 0x5d:
          return Singletons.rightBracket;
        case 0x7c:
          return Singletons.or;
        default:
          return this.getIdentifier();
      }
    }
    return Singletons.eof;
  }
}
exports.Lexer = Lexer;