pdfjs-dist/lib/core/ps_parser.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2019 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.PostScriptParser = exports.PostScriptLexer = void 0;

var _util = require("../shared/util");

var _primitives = require("./primitives");

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var PostScriptParser =
/*#__PURE__*/
function () {
  function PostScriptParser(lexer) {
    _classCallCheck(this, PostScriptParser);

    this.lexer = lexer;
    this.operators = [];
    this.token = null;
    this.prev = null;
  }

  _createClass(PostScriptParser, [{
    key: "nextToken",
    value: function nextToken() {
      this.prev = this.token;
      this.token = this.lexer.getToken();
    }
  }, {
    key: "accept",
    value: function accept(type) {
      if (this.token.type === type) {
        this.nextToken();
        return true;
      }

      return false;
    }
  }, {
    key: "expect",
    value: function expect(type) {
      if (this.accept(type)) {
        return true;
      }

      throw new _util.FormatError("Unexpected symbol: found ".concat(this.token.type, " expected ").concat(type, "."));
    }
  }, {
    key: "parse",
    value: function parse() {
      this.nextToken();
      this.expect(PostScriptTokenTypes.LBRACE);
      this.parseBlock();
      this.expect(PostScriptTokenTypes.RBRACE);
      return this.operators;
    }
  }, {
    key: "parseBlock",
    value: function parseBlock() {
      while (true) {
        if (this.accept(PostScriptTokenTypes.NUMBER)) {
          this.operators.push(this.prev.value);
        } else if (this.accept(PostScriptTokenTypes.OPERATOR)) {
          this.operators.push(this.prev.value);
        } else if (this.accept(PostScriptTokenTypes.LBRACE)) {
          this.parseCondition();
        } else {
          return;
        }
      }
    }
  }, {
    key: "parseCondition",
    value: function parseCondition() {
      var conditionLocation = this.operators.length;
      this.operators.push(null, null);
      this.parseBlock();
      this.expect(PostScriptTokenTypes.RBRACE);

      if (this.accept(PostScriptTokenTypes.IF)) {
        this.operators[conditionLocation] = this.operators.length;
        this.operators[conditionLocation + 1] = 'jz';
      } else if (this.accept(PostScriptTokenTypes.LBRACE)) {
        var jumpLocation = this.operators.length;
        this.operators.push(null, null);
        var endOfTrue = this.operators.length;
        this.parseBlock();
        this.expect(PostScriptTokenTypes.RBRACE);
        this.expect(PostScriptTokenTypes.IFELSE);
        this.operators[jumpLocation] = this.operators.length;
        this.operators[jumpLocation + 1] = 'j';
        this.operators[conditionLocation] = endOfTrue;
        this.operators[conditionLocation + 1] = 'jz';
      } else {
        throw new _util.FormatError('PS Function: error parsing conditional.');
      }
    }
  }]);

  return PostScriptParser;
}();

exports.PostScriptParser = PostScriptParser;
var PostScriptTokenTypes = {
  LBRACE: 0,
  RBRACE: 1,
  NUMBER: 2,
  OPERATOR: 3,
  IF: 4,
  IFELSE: 5
};

var PostScriptToken = function PostScriptTokenClosure() {
  var opCache = Object.create(null);

  var PostScriptToken =
  /*#__PURE__*/
  function () {
    function PostScriptToken(type, value) {
      _classCallCheck(this, PostScriptToken);

      this.type = type;
      this.value = value;
    }

    _createClass(PostScriptToken, null, [{
      key: "getOperator",
      value: function getOperator(op) {
        var opValue = opCache[op];

        if (opValue) {
          return opValue;
        }

        return opCache[op] = new PostScriptToken(PostScriptTokenTypes.OPERATOR, op);
      }
    }, {
      key: "LBRACE",
      get: function get() {
        return (0, _util.shadow)(this, 'LBRACE', new PostScriptToken(PostScriptTokenTypes.LBRACE, '{'));
      }
    }, {
      key: "RBRACE",
      get: function get() {
        return (0, _util.shadow)(this, 'RBRACE', new PostScriptToken(PostScriptTokenTypes.RBRACE, '}'));
      }
    }, {
      key: "IF",
      get: function get() {
        return (0, _util.shadow)(this, 'IF', new PostScriptToken(PostScriptTokenTypes.IF, 'IF'));
      }
    }, {
      key: "IFELSE",
      get: function get() {
        return (0, _util.shadow)(this, 'IFELSE', new PostScriptToken(PostScriptTokenTypes.IFELSE, 'IFELSE'));
      }
    }]);

    return PostScriptToken;
  }();

  return PostScriptToken;
}();

var PostScriptLexer =
/*#__PURE__*/
function () {
  function PostScriptLexer(stream) {
    _classCallCheck(this, PostScriptLexer);

    this.stream = stream;
    this.nextChar();
    this.strBuf = [];
  }

  _createClass(PostScriptLexer, [{
    key: "nextChar",
    value: function nextChar() {
      return this.currentChar = this.stream.getByte();
    }
  }, {
    key: "getToken",
    value: function getToken() {
      var comment = false;
      var ch = this.currentChar;

      while (true) {
        if (ch < 0) {
          return _primitives.EOF;
        }

        if (comment) {
          if (ch === 0x0A || ch === 0x0D) {
            comment = false;
          }
        } else if (ch === 0x25) {
          comment = true;
        } else if (!(0, _util.isSpace)(ch)) {
          break;
        }

        ch = this.nextChar();
      }

      switch (ch | 0) {
        case 0x30:
        case 0x31:
        case 0x32:
        case 0x33:
        case 0x34:
        case 0x35:
        case 0x36:
        case 0x37:
        case 0x38:
        case 0x39:
        case 0x2B:
        case 0x2D:
        case 0x2E:
          return new PostScriptToken(PostScriptTokenTypes.NUMBER, this.getNumber());

        case 0x7B:
          this.nextChar();
          return PostScriptToken.LBRACE;

        case 0x7D:
          this.nextChar();
          return PostScriptToken.RBRACE;
      }

      var strBuf = this.strBuf;
      strBuf.length = 0;
      strBuf[0] = String.fromCharCode(ch);

      while ((ch = this.nextChar()) >= 0 && (ch >= 0x41 && ch <= 0x5A || ch >= 0x61 && ch <= 0x7A)) {
        strBuf.push(String.fromCharCode(ch));
      }

      var str = strBuf.join('');

      switch (str.toLowerCase()) {
        case 'if':
          return PostScriptToken.IF;

        case 'ifelse':
          return PostScriptToken.IFELSE;

        default:
          return PostScriptToken.getOperator(str);
      }
    }
  }, {
    key: "getNumber",
    value: function getNumber() {
      var ch = this.currentChar;
      var strBuf = this.strBuf;
      strBuf.length = 0;
      strBuf[0] = String.fromCharCode(ch);

      while ((ch = this.nextChar()) >= 0) {
        if (ch >= 0x30 && ch <= 0x39 || ch === 0x2D || ch === 0x2E) {
          strBuf.push(String.fromCharCode(ch));
        } else {
          break;
        }
      }

      var value = parseFloat(strBuf.join(''));

      if (isNaN(value)) {
        throw new _util.FormatError("Invalid floating point number: ".concat(value));
      }

      return value;
    }
  }]);

  return PostScriptLexer;
}();

exports.PostScriptLexer = PostScriptLexer;