414 lines
15 KiB
JavaScript
414 lines
15 KiB
JavaScript
/*global Buffer*/
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// Named constants with unique integer values
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var C = {};
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// 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);
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}
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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{
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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
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if ((n >= 0x30 && n < 0x40) || (n > 0x40 && n <= 0x46) || (n > 0x60 && n <= 0x66)) {
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this.unicode += String.fromCharCode(n);
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if (this.tState++ === STRING6) {
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var intVal = parseInt(this.unicode, 16);
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this.unicode = undefined;
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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;
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} else {
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if (this.highSurrogate !== undefined) {
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this.appendStringBuf(new Buffer(String.fromCharCode(this.highSurrogate)));
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this.highSurrogate = undefined;
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}
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this.appendStringBuf(new Buffer(String.fromCharCode(intVal)));
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}
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this.tState = STRING1;
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}
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} else {
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return this.charError(buffer, i);
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}
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} else if (this.tState === NUMBER1 || this.tState === NUMBER3) {
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n = buffer[i];
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switch (n) {
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case 0x30: // 0
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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: // +
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case 0x2d: // -
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this.string += String.fromCharCode(n);
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this.tState = NUMBER3;
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break;
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default:
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this.tState = START;
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var result = Number(this.string);
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if (isNaN(result)){
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return this.charError(buffer, i);
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}
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if ((this.string.match(/[0-9]+/) == this.string) && (result.toString() != this.string)) {
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// Long string of digits which is an ID string and not valid and/or safe JavaScript integer Number
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this.onToken(STRING, this.string);
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} else {
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this.onToken(NUMBER, result);
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}
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this.offset += this.string.length - 1;
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this.string = undefined;
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i--;
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break;
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}
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}else if (this.tState === TRUE1){ // r
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if (buffer[i] === 0x72) { this.tState = TRUE2; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === TRUE2){ // u
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if (buffer[i] === 0x75) { this.tState = TRUE3; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === TRUE3){ // e
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if (buffer[i] === 0x65) { this.tState = START; this.onToken(TRUE, true); this.offset+= 3; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === FALSE1){ // a
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if (buffer[i] === 0x61) { this.tState = FALSE2; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === FALSE2){ // l
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if (buffer[i] === 0x6c) { this.tState = FALSE3; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === FALSE3){ // s
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if (buffer[i] === 0x73) { this.tState = FALSE4; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === FALSE4){ // e
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if (buffer[i] === 0x65) { this.tState = START; this.onToken(FALSE, false); this.offset+= 4; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === NULL1){ // u
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if (buffer[i] === 0x75) { this.tState = NULL2; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === NULL2){ // l
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if (buffer[i] === 0x6c) { this.tState = NULL3; }
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else { return this.charError(buffer, i); }
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}else if (this.tState === NULL3){ // l
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if (buffer[i] === 0x6c) { this.tState = START; this.onToken(NULL, null); this.offset += 3; }
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else { return this.charError(buffer, i); }
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}
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}
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};
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proto.onToken = function (token, value) {
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// Override this to get events
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};
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proto.parseError = function (token, value) {
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this.tState = STOP;
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this.onError(new Error("Unexpected " + Parser.toknam(token) + (value ? ("(" + JSON.stringify(value) + ")") : "") + " in state " + Parser.toknam(this.state)));
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};
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proto.push = function () {
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this.stack.push({value: this.value, key: this.key, mode: this.mode});
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};
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proto.pop = function () {
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var value = this.value;
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var parent = this.stack.pop();
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this.value = parent.value;
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this.key = parent.key;
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this.mode = parent.mode;
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this.emit(value);
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if (!this.mode) { this.state = VALUE; }
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};
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proto.emit = function (value) {
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if (this.mode) { this.state = COMMA; }
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this.onValue(value);
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};
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proto.onValue = function (value) {
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// Override me
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};
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proto.onToken = function (token, value) {
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if(this.state === VALUE){
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if(token === STRING || token === NUMBER || token === TRUE || token === FALSE || token === NULL){
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if (this.value) {
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this.value[this.key] = value;
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}
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this.emit(value);
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}else if(token === LEFT_BRACE){
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this.push();
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if (this.value) {
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this.value = this.value[this.key] = {};
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} else {
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this.value = {};
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}
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this.key = undefined;
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this.state = KEY;
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this.mode = OBJECT;
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}else if(token === LEFT_BRACKET){
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this.push();
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if (this.value) {
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this.value = this.value[this.key] = [];
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} else {
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this.value = [];
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}
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this.key = 0;
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this.mode = ARRAY;
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this.state = VALUE;
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}else if(token === RIGHT_BRACE){
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if (this.mode === OBJECT) {
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this.pop();
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} else {
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return this.parseError(token, value);
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}
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}else if(token === RIGHT_BRACKET){
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if (this.mode === ARRAY) {
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this.pop();
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} else {
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return this.parseError(token, value);
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}
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}else{
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return this.parseError(token, value);
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}
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}else if(this.state === KEY){
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if (token === STRING) {
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this.key = value;
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this.state = COLON;
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} else if (token === RIGHT_BRACE) {
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this.pop();
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} else {
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return this.parseError(token, value);
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}
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}else if(this.state === COLON){
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if (token === COLON) { this.state = VALUE; }
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else { return this.parseError(token, value); }
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}else if(this.state === COMMA){
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if (token === COMMA) {
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if (this.mode === ARRAY) { this.key++; this.state = VALUE; }
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else if (this.mode === OBJECT) { this.state = KEY; }
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} else if (token === RIGHT_BRACKET && this.mode === ARRAY || token === RIGHT_BRACE && this.mode === OBJECT) {
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this.pop();
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} else {
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return this.parseError(token, value);
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}
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}else{
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return this.parseError(token, value);
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}
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};
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Parser.C = C;
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module.exports = Parser;
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