pdfjs-dist/lib/core/ps_parser.js

/* Copyright 2017 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.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var corePrimitives = require('./primitives.js');
var error = sharedUtil.error;
var isSpace = sharedUtil.isSpace;
var EOF = corePrimitives.EOF;
var PostScriptParser = function PostScriptParserClosure() {
 function PostScriptParser(lexer) {
  this.lexer = lexer;
  this.operators = [];
  this.token = null;
  this.prev = null;
 }
 PostScriptParser.prototype = {
  nextToken: function PostScriptParser_nextToken() {
   this.prev = this.token;
   this.token = this.lexer.getToken();
  },
  accept: function PostScriptParser_accept(type) {
   if (this.token.type === type) {
    this.nextToken();
    return true;
   }
   return false;
  },
  expect: function PostScriptParser_expect(type) {
   if (this.accept(type)) {
    return true;
   }
   error('Unexpected symbol: found ' + this.token.type + ' expected ' + type + '.');
  },
  parse: function PostScriptParser_parse() {
   this.nextToken();
   this.expect(PostScriptTokenTypes.LBRACE);
   this.parseBlock();
   this.expect(PostScriptTokenTypes.RBRACE);
   return this.operators;
  },
  parseBlock: function PostScriptParser_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;
    }
   }
  },
  parseCondition: function PostScriptParser_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 {
    error('PS Function: error parsing conditional.');
   }
  }
 };
 return PostScriptParser;
}();
var PostScriptTokenTypes = {
 LBRACE: 0,
 RBRACE: 1,
 NUMBER: 2,
 OPERATOR: 3,
 IF: 4,
 IFELSE: 5
};
var PostScriptToken = function PostScriptTokenClosure() {
 function PostScriptToken(type, value) {
  this.type = type;
  this.value = value;
 }
 var opCache = Object.create(null);
 PostScriptToken.getOperator = function PostScriptToken_getOperator(op) {
  var opValue = opCache[op];
  if (opValue) {
   return opValue;
  }
  return opCache[op] = new PostScriptToken(PostScriptTokenTypes.OPERATOR, op);
 };
 PostScriptToken.LBRACE = new PostScriptToken(PostScriptTokenTypes.LBRACE, '{');
 PostScriptToken.RBRACE = new PostScriptToken(PostScriptTokenTypes.RBRACE, '}');
 PostScriptToken.IF = new PostScriptToken(PostScriptTokenTypes.IF, 'IF');
 PostScriptToken.IFELSE = new PostScriptToken(PostScriptTokenTypes.IFELSE, 'IFELSE');
 return PostScriptToken;
}();
var PostScriptLexer = function PostScriptLexerClosure() {
 function PostScriptLexer(stream) {
  this.stream = stream;
  this.nextChar();
  this.strBuf = [];
 }
 PostScriptLexer.prototype = {
  nextChar: function PostScriptLexer_nextChar() {
   return this.currentChar = this.stream.getByte();
  },
  getToken: function PostScriptLexer_getToken() {
   var comment = false;
   var ch = this.currentChar;
   while (true) {
    if (ch < 0) {
     return EOF;
    }
    if (comment) {
     if (ch === 0x0A || ch === 0x0D) {
      comment = false;
     }
    } else if (ch === 0x25) {
     comment = true;
    } else if (!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);
   }
  },
  getNumber: function PostScriptLexer_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)) {
    error('Invalid floating point number: ' + value);
   }
   return value;
  }
 };
 return PostScriptLexer;
}();
exports.PostScriptLexer = PostScriptLexer;
exports.PostScriptParser = PostScriptParser;