jsonparse.js ➔ Parser   A
last analyzed

Complexity

Conditions 2
Paths 2

Size

Total Lines 21

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 2
nc 2
dl 0
loc 21
rs 9.3142
c 0
b 0
f 0
nop 0
1
/*global Buffer*/
2
// Named constants with unique integer values
3
var C = {};
4
// Tokens
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var LEFT_BRACE    = C.LEFT_BRACE    = 0x1;
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var RIGHT_BRACE   = C.RIGHT_BRACE   = 0x2;
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var LEFT_BRACKET  = C.LEFT_BRACKET  = 0x3;
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var RIGHT_BRACKET = C.RIGHT_BRACKET = 0x4;
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var COLON         = C.COLON         = 0x5;
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var COMMA         = C.COMMA         = 0x6;
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var TRUE          = C.TRUE          = 0x7;
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var FALSE         = C.FALSE         = 0x8;
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var NULL          = C.NULL          = 0x9;
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var STRING        = C.STRING        = 0xa;
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var NUMBER        = C.NUMBER        = 0xb;
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// Tokenizer States
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var START   = C.START   = 0x11;
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var STOP    = C.STOP    = 0x12;
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var TRUE1   = C.TRUE1   = 0x21;
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var TRUE2   = C.TRUE2   = 0x22;
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var TRUE3   = C.TRUE3   = 0x23;
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var FALSE1  = C.FALSE1  = 0x31;
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var FALSE2  = C.FALSE2  = 0x32;
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var FALSE3  = C.FALSE3  = 0x33;
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var FALSE4  = C.FALSE4  = 0x34;
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var NULL1   = C.NULL1   = 0x41;
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var NULL2   = C.NULL2   = 0x42;
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var NULL3   = C.NULL3   = 0x43;
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var NUMBER1 = C.NUMBER1 = 0x51;
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var NUMBER3 = C.NUMBER3 = 0x53;
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var STRING1 = C.STRING1 = 0x61;
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var STRING2 = C.STRING2 = 0x62;
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var STRING3 = C.STRING3 = 0x63;
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var STRING4 = C.STRING4 = 0x64;
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var STRING5 = C.STRING5 = 0x65;
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var STRING6 = C.STRING6 = 0x66;
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// Parser States
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var VALUE   = C.VALUE   = 0x71;
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var KEY     = C.KEY     = 0x72;
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// Parser Modes
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var OBJECT  = C.OBJECT  = 0x81;
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var ARRAY   = C.ARRAY   = 0x82;
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// Character constants
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var BACK_SLASH =      "\\".charCodeAt(0);
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var FORWARD_SLASH =   "\/".charCodeAt(0);
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var BACKSPACE =       "\b".charCodeAt(0);
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var FORM_FEED =       "\f".charCodeAt(0);
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var NEWLINE =         "\n".charCodeAt(0);
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var CARRIAGE_RETURN = "\r".charCodeAt(0);
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var TAB =             "\t".charCodeAt(0);
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var STRING_BUFFER_SIZE = 64 * 1024;
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function Parser() {
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  this.tState = START;
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  this.value = undefined;
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  this.string = undefined; // string data
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  this.stringBuffer = Buffer.alloc ? Buffer.alloc(STRING_BUFFER_SIZE) : new Buffer(STRING_BUFFER_SIZE);
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  this.stringBufferOffset = 0;
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  this.unicode = undefined; // unicode escapes
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  this.highSurrogate = undefined;
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  this.key = undefined;
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  this.mode = undefined;
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  this.stack = [];
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  this.state = VALUE;
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  this.bytes_remaining = 0; // number of bytes remaining in multi byte utf8 char to read after split boundary
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  this.bytes_in_sequence = 0; // bytes in multi byte utf8 char to read
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  this.temp_buffs = { "2": new Buffer(2), "3": new Buffer(3), "4": new Buffer(4) }; // for rebuilding chars split before boundary is reached
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  // Stream offset
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  this.offset = -1;
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}
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// Slow code to string converter (only used when throwing syntax errors)
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Parser.toknam = function (code) {
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  var keys = Object.keys(C);
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  for (var i = 0, l = keys.length; i < l; i++) {
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    var key = keys[i];
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    if (C[key] === code) { return key; }
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  }
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  return code && ("0x" + code.toString(16));
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};
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var proto = Parser.prototype;
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proto.onError = function (err) { throw err; };
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proto.charError = function (buffer, i) {
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  this.tState = STOP;
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  this.onError(new Error("Unexpected " + JSON.stringify(String.fromCharCode(buffer[i])) + " at position " + i + " in state " + Parser.toknam(this.tState)));
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};
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proto.appendStringChar = function (char) {
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  if (this.stringBufferOffset >= STRING_BUFFER_SIZE) {
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    this.string += this.stringBuffer.toString('utf8');
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    this.stringBufferOffset = 0;
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  }
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  this.stringBuffer[this.stringBufferOffset++] = char;
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};
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proto.appendStringBuf = function (buf, start, end) {
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  var size = buf.length;
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  if (typeof start === 'number') {
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    if (typeof end === 'number') {
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      if (end < 0) {
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        // adding a negative end decreeses the size
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        size = buf.length - start + end;
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      } else {
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        size = end - start;
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      }
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    } else {
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      size = buf.length - start;
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    }
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  }
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  if (size < 0) {
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    size = 0;
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  }
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  if (this.stringBufferOffset + size > STRING_BUFFER_SIZE) {
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    this.string += this.stringBuffer.toString('utf8', 0, this.stringBufferOffset);
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    this.stringBufferOffset = 0;
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  }
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  buf.copy(this.stringBuffer, this.stringBufferOffset, start, end);
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  this.stringBufferOffset += size;
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};
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proto.write = function (buffer) {
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  if (typeof buffer === "string") buffer = new Buffer(buffer);
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  var n;
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  for (var i = 0, l = buffer.length; i < l; i++) {
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    if (this.tState === START){
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      n = buffer[i];
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      this.offset++;
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      if(n === 0x7b){ this.onToken(LEFT_BRACE, "{"); // {
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      }else if(n === 0x7d){ this.onToken(RIGHT_BRACE, "}"); // }
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      }else if(n === 0x5b){ this.onToken(LEFT_BRACKET, "["); // [
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      }else if(n === 0x5d){ this.onToken(RIGHT_BRACKET, "]"); // ]
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      }else if(n === 0x3a){ this.onToken(COLON, ":");  // :
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      }else if(n === 0x2c){ this.onToken(COMMA, ","); // ,
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      }else if(n === 0x74){ this.tState = TRUE1;  // t
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      }else if(n === 0x66){ this.tState = FALSE1;  // f
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      }else if(n === 0x6e){ this.tState = NULL1; // n
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      }else if(n === 0x22){ // "
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        this.string = "";
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        this.stringBufferOffset = 0;
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        this.tState = STRING1;
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      }else if(n === 0x2d){ this.string = "-"; this.tState = NUMBER1; // -
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      }else{
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        if (n >= 0x30 && n < 0x40) { // 1-9
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          this.string = String.fromCharCode(n); this.tState = NUMBER3;
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        } else if (n === 0x20 || n === 0x09 || n === 0x0a || n === 0x0d) {
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          // whitespace
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        } else {
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          return this.charError(buffer, i);
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        }
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      }
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    }else if (this.tState === STRING1){ // After open quote
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      n = buffer[i]; // get current byte from buffer
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      // check for carry over of a multi byte char split between data chunks
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      // & fill temp buffer it with start of this data chunk up to the boundary limit set in the last iteration
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      if (this.bytes_remaining > 0) {
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        for (var j = 0; j < this.bytes_remaining; j++) {
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          this.temp_buffs[this.bytes_in_sequence][this.bytes_in_sequence - this.bytes_remaining + j] = buffer[j];
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        }
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        this.appendStringBuf(this.temp_buffs[this.bytes_in_sequence]);
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        this.bytes_in_sequence = this.bytes_remaining = 0;
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        i = i + j - 1;
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      } else if (this.bytes_remaining === 0 && n >= 128) { // else if no remainder bytes carried over, parse multi byte (>=128) chars one at a time
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        if (n <= 193 || n > 244) {
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          return this.onError(new Error("Invalid UTF-8 character at position " + i + " in state " + Parser.toknam(this.tState)));
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        }
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        if ((n >= 194) && (n <= 223)) this.bytes_in_sequence = 2;
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        if ((n >= 224) && (n <= 239)) this.bytes_in_sequence = 3;
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        if ((n >= 240) && (n <= 244)) this.bytes_in_sequence = 4;
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        if ((this.bytes_in_sequence + i) > buffer.length) { // if bytes needed to complete char fall outside buffer length, we have a boundary split
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          for (var k = 0; k <= (buffer.length - 1 - i); k++) {
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            this.temp_buffs[this.bytes_in_sequence][k] = buffer[i + k]; // fill temp buffer of correct size with bytes available in this chunk
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          }
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          this.bytes_remaining = (i + this.bytes_in_sequence) - buffer.length;
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          i = buffer.length - 1;
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        } else {
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          this.appendStringBuf(buffer, i, i + this.bytes_in_sequence);
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          i = i + this.bytes_in_sequence - 1;
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        }
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      } else if (n === 0x22) {
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        this.tState = START;
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        this.string += this.stringBuffer.toString('utf8', 0, this.stringBufferOffset);
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        this.stringBufferOffset = 0;
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        this.onToken(STRING, this.string);
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        this.offset += Buffer.byteLength(this.string, 'utf8') + 1;
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        this.string = undefined;
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      }
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      else if (n === 0x5c) {
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        this.tState = STRING2;
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      }
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      else if (n >= 0x20) { this.appendStringChar(n); }
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      else {
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          return this.charError(buffer, i);
200
      }
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    }else if (this.tState === STRING2){ // After backslash
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      n = buffer[i];
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      if(n === 0x22){ this.appendStringChar(n); this.tState = STRING1;
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      }else if(n === 0x5c){ this.appendStringChar(BACK_SLASH); this.tState = STRING1;
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      }else if(n === 0x2f){ this.appendStringChar(FORWARD_SLASH); this.tState = STRING1;
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      }else if(n === 0x62){ this.appendStringChar(BACKSPACE); this.tState = STRING1;
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      }else if(n === 0x66){ this.appendStringChar(FORM_FEED); this.tState = STRING1;
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      }else if(n === 0x6e){ this.appendStringChar(NEWLINE); this.tState = STRING1;
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      }else if(n === 0x72){ this.appendStringChar(CARRIAGE_RETURN); this.tState = STRING1;
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      }else if(n === 0x74){ this.appendStringChar(TAB); this.tState = STRING1;
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      }else if(n === 0x75){ this.unicode = ""; this.tState = STRING3;
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      }else{
213
        return this.charError(buffer, i);
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      }
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    }else if (this.tState === STRING3 || this.tState === STRING4 || this.tState === STRING5 || this.tState === STRING6){ // unicode hex codes
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      n = buffer[i];
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      // 0-9 A-F a-f
218
      if ((n >= 0x30 && n < 0x40) || (n > 0x40 && n <= 0x46) || (n > 0x60 && n <= 0x66)) {
219
        this.unicode += String.fromCharCode(n);
220
        if (this.tState++ === STRING6) {
221
          var intVal = parseInt(this.unicode, 16);
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          this.unicode = undefined;
223
          if (this.highSurrogate !== undefined && intVal >= 0xDC00 && intVal < (0xDFFF + 1)) { //<56320,57343> - lowSurrogate
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            this.appendStringBuf(new Buffer(String.fromCharCode(this.highSurrogate, intVal)));
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            this.highSurrogate = undefined;
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          } else if (this.highSurrogate === undefined && intVal >= 0xD800 && intVal < (0xDBFF + 1)) { //<55296,56319> - highSurrogate
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            this.highSurrogate = intVal;
228
          } else {
229
            if (this.highSurrogate !== undefined) {
230
              this.appendStringBuf(new Buffer(String.fromCharCode(this.highSurrogate)));
231
              this.highSurrogate = undefined;
232
            }
233
            this.appendStringBuf(new Buffer(String.fromCharCode(intVal)));
234
          }
235
          this.tState = STRING1;
236
        }
237
      } else {
238
        return this.charError(buffer, i);
239
      }
240
    } else if (this.tState === NUMBER1 || this.tState === NUMBER3) {
241
        n = buffer[i];
242
243
        switch (n) {
244
          case 0x30: // 0
245
          case 0x31: // 1
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          case 0x32: // 2
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          case 0x33: // 3
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          case 0x34: // 4
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          case 0x35: // 5
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          case 0x36: // 6
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          case 0x37: // 7
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          case 0x38: // 8
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          case 0x39: // 9
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          case 0x2e: // .
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          case 0x65: // e
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          case 0x45: // E
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          case 0x2b: // +
258
          case 0x2d: // -
259
            this.string += String.fromCharCode(n);
260
            this.tState = NUMBER3;
261
            break;
262
          default:
263
            this.tState = START;
264
            var result = Number(this.string);
265
266
            if (isNaN(result)){
267
              return this.charError(buffer, i);
268
            }
269
270
            if ((this.string.match(/[0-9]+/) == this.string) && (result.toString() != this.string)) {
271
              // Long string of digits which is an ID string and not valid and/or safe JavaScript integer Number
272
              this.onToken(STRING, this.string);
273
            } else {
274
              this.onToken(NUMBER, result);
275
            }
276
277
            this.offset += this.string.length - 1;
278
            this.string = undefined;
279
            i--;
280
            break;
281
        }
282
    }else if (this.tState === TRUE1){ // r
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      if (buffer[i] === 0x72) { this.tState = TRUE2; }
284
      else { return this.charError(buffer, i); }
285
    }else if (this.tState === TRUE2){ // u
286
      if (buffer[i] === 0x75) { this.tState = TRUE3; }
287
      else { return this.charError(buffer, i); }
288
    }else if (this.tState === TRUE3){ // e
289
      if (buffer[i] === 0x65) { this.tState = START; this.onToken(TRUE, true); this.offset+= 3; }
290
      else { return this.charError(buffer, i); }
291
    }else if (this.tState === FALSE1){ // a
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      if (buffer[i] === 0x61) { this.tState = FALSE2; }
293
      else { return this.charError(buffer, i); }
294
    }else if (this.tState === FALSE2){ // l
295
      if (buffer[i] === 0x6c) { this.tState = FALSE3; }
296
      else { return this.charError(buffer, i); }
297
    }else if (this.tState === FALSE3){ // s
298
      if (buffer[i] === 0x73) { this.tState = FALSE4; }
299
      else { return this.charError(buffer, i); }
300
    }else if (this.tState === FALSE4){ // e
301
      if (buffer[i] === 0x65) { this.tState = START; this.onToken(FALSE, false); this.offset+= 4; }
302
      else { return this.charError(buffer, i); }
303
    }else if (this.tState === NULL1){ // u
304
      if (buffer[i] === 0x75) { this.tState = NULL2; }
305
      else { return this.charError(buffer, i); }
306
    }else if (this.tState === NULL2){ // l
307
      if (buffer[i] === 0x6c) { this.tState = NULL3; }
308
      else { return this.charError(buffer, i); }
309
    }else if (this.tState === NULL3){ // l
310
      if (buffer[i] === 0x6c) { this.tState = START; this.onToken(NULL, null); this.offset += 3; }
311
      else { return this.charError(buffer, i); }
312
    }
313
  }
314
};
315
proto.onToken = function (token, value) {
316
  // Override this to get events
317
};
318
319
proto.parseError = function (token, value) {
320
  this.tState = STOP;
321
  this.onError(new Error("Unexpected " + Parser.toknam(token) + (value ? ("(" + JSON.stringify(value) + ")") : "") + " in state " + Parser.toknam(this.state)));
322
};
323
proto.push = function () {
324
  this.stack.push({value: this.value, key: this.key, mode: this.mode});
325
};
326
proto.pop = function () {
327
  var value = this.value;
328
  var parent = this.stack.pop();
329
  this.value = parent.value;
330
  this.key = parent.key;
331
  this.mode = parent.mode;
332
  this.emit(value);
333
  if (!this.mode) { this.state = VALUE; }
334
};
335
proto.emit = function (value) {
336
  if (this.mode) { this.state = COMMA; }
337
  this.onValue(value);
338
};
339
proto.onValue = function (value) {
340
  // Override me
341
};
342
proto.onToken = function (token, value) {
343
  if(this.state === VALUE){
344 View Code Duplication
    if(token === STRING || token === NUMBER || token === TRUE || token === FALSE || token === NULL){
345
      if (this.value) {
346
        this.value[this.key] = value;
347
      }
348
      this.emit(value);
349
    }else if(token === LEFT_BRACE){
350
      this.push();
351
      if (this.value) {
352
        this.value = this.value[this.key] = {};
353
      } else {
354
        this.value = {};
355
      }
356
      this.key = undefined;
357
      this.state = KEY;
358
      this.mode = OBJECT;
359
    }else if(token === LEFT_BRACKET){
360
      this.push();
361
      if (this.value) {
362
        this.value = this.value[this.key] = [];
363
      } else {
364
        this.value = [];
365
      }
366
      this.key = 0;
367
      this.mode = ARRAY;
368
      this.state = VALUE;
369
    }else if(token === RIGHT_BRACE){
370
      if (this.mode === OBJECT) {
371
        this.pop();
372
      } else {
373
        return this.parseError(token, value);
374
      }
375
    }else if(token === RIGHT_BRACKET){
376
      if (this.mode === ARRAY) {
377
        this.pop();
378
      } else {
379
        return this.parseError(token, value);
380
      }
381
    }else{
382
      return this.parseError(token, value);
383
    }
384 View Code Duplication
  }else if(this.state === KEY){
385
    if (token === STRING) {
386
      this.key = value;
387
      this.state = COLON;
388
    } else if (token === RIGHT_BRACE) {
389
      this.pop();
390
    } else {
391
      return this.parseError(token, value);
392
    }
393
  }else if(this.state === COLON){
394
    if (token === COLON) { this.state = VALUE; }
395
    else { return this.parseError(token, value); }
396
  }else if(this.state === COMMA){
397
    if (token === COMMA) {
398
      if (this.mode === ARRAY) { this.key++; this.state = VALUE; }
399
      else if (this.mode === OBJECT) { this.state = KEY; }
400
401
    } else if (token === RIGHT_BRACKET && this.mode === ARRAY || token === RIGHT_BRACE && this.mode === OBJECT) {
402
      this.pop();
403
    } else {
404
      return this.parseError(token, value);
405
    }
406
  }else{
407
    return this.parseError(token, value);
408
  }
409
};
410
411
Parser.C = C;
412
413
module.exports = Parser;
414