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      1 // Copyright 2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 
     29 /**
     30  * Creates a CSV lines parser.
     31  */
     32 class CsvParser {
     33   /**
     34    * Converts \x00 and \u0000 escape sequences in the given string.
     35    *
     36    * @param {string} input field.
     37    **/
     38   escapeField(string) {
     39     let nextPos = string.indexOf("\\");
     40     if (nextPos === -1) return string;
     41 
     42     let result = string.substring(0, nextPos);
     43     // Escape sequences of the form \x00 and \u0000;
     44     let endPos = string.length;
     45     let pos = 0;
     46     while (nextPos !== -1) {
     47       let escapeIdentifier = string.charAt(nextPos + 1);
     48       pos = nextPos + 2;
     49       if (escapeIdentifier == 'n') {
     50         result += '\n';
     51         nextPos = pos;
     52       } else if (escapeIdentifier == '\\') {
     53         result += '\\';
     54         nextPos = pos;
     55       } else {
     56         if (escapeIdentifier == 'x') {
     57           // \x00 ascii range escapes consume 2 chars.
     58           nextPos = pos + 2;
     59         } else {
     60           // \u0000 unicode range escapes consume 4 chars.
     61           nextPos = pos + 4;
     62         }
     63         // Convert the selected escape sequence to a single character.
     64         let escapeChars = string.substring(pos, nextPos);
     65         result += String.fromCharCode(parseInt(escapeChars, 16));
     66       }
     67 
     68       // Continue looking for the next escape sequence.
     69       pos = nextPos;
     70       nextPos = string.indexOf("\\", pos);
     71       // If there are no more escape sequences consume the rest of the string.
     72       if (nextPos === -1) {
     73         result += string.substr(pos);
     74       } else if (pos != nextPos) {
     75         result += string.substring(pos, nextPos);
     76       }
     77     }
     78     return result;
     79   }
     80 
     81   /**
     82    * Parses a line of CSV-encoded values. Returns an array of fields.
     83    *
     84    * @param {string} line Input line.
     85    */
     86   parseLine(line) {
     87     var pos = 0;
     88     var endPos = line.length;
     89     var fields = [];
     90     if (endPos == 0) return fields;
     91     let nextPos = 0;
     92     while(nextPos !== -1) {
     93       nextPos = line.indexOf(',', pos);
     94       let field;
     95       if (nextPos === -1) {
     96         field = line.substr(pos);
     97       } else {
     98         field = line.substring(pos, nextPos);
     99       }
    100       fields.push(this.escapeField(field));
    101       pos = nextPos + 1;
    102     };
    103     return fields
    104   }
    105 }
    106