Merge pull request #4236 from lovasoa/master

Lexer_getNumber faster number parsing

AUTHORS

@@ -15,6 +15,7 @@ Jonas Jenwald <jonas.jenwald@gmail.com>
 Julian Viereck
 Justin D'Arcangelo <justindarc@gmail.com>
 Kalervo Kujala
+Ophir Lojkine <@lovasoa>
 Rob Wu <gwnRob@gmail.com>
 Shaon Barman <shaon.barman@gmail.com>
 Tim van der Meij <info@timvandermeij.nl>

src/core/parser.js

@@ -393,47 +393,85 @@ var Lexer = (function LexerClosure() {
     nextChar: function Lexer_nextChar() {
       return (this.currentChar = this.stream.getByte());
     },
+    peekChar: function Lexer_peekChar() {
+      return this.stream.peekBytes(1)[0];
+    },
     getNumber: function Lexer_getNumber() {
-      var floating = false;
       var ch = this.currentChar;
-      var allDigits = ch >= 0x30 && ch <= 0x39;
-      var strBuf = this.strBuf;
-      strBuf.length = 0;
-      strBuf.push(String.fromCharCode(ch));
+      var eNotation = false;
+      var divideBy = 0; // different from 0 if it's a floating point value
+
+      var sign = 1;
+
+
+      if (ch === 0x2D) { // '-'
+        sign = -1;
+        ch = this.nextChar();
+      } else if (ch === 0x2B) { // '+'
+        ch = this.nextChar();
+      }
+      if (ch === 0x2E) { // '.'
+        divideBy = 10;
+        ch = this.nextChar();
+      }
+
+      if (ch < 0x30 || ch > 0x39) { // '0' - '9'
+        error('Invalid number: ' + String.fromCharCode(ch));
+        return 0;
+      }
+
+      var baseValue = ch - 0x30; // '0'
+      var powerValue = 0;
+      var powerValueSign = 1;
+
       while ((ch = this.nextChar()) >= 0) {
-        if (ch >= 0x30 && ch <= 0x39) { // '0'-'9'
-          strBuf.push(String.fromCharCode(ch));
-        } else if (ch === 0x2E && !floating) { // '.'
-          strBuf.push('.');
-          floating = true;
-          allDigits = false;
+        if (0x30 <= ch && ch <= 0x39) { // '0' - '9'
+          var currentDigit = ch - 0x30; // '0'
+          if (eNotation) { // We are after an 'e' or 'E'
+            powerValue = powerValue * 10 + currentDigit;
+          } else {
+            if (divideBy !== 0) { // We are after a point
+              divideBy *= 10;
+            }
+            baseValue = baseValue * 10 + currentDigit;
+          }
+        } else if (ch === 0x2E) { // '.'
+          if (divideBy === 0) {
+            divideBy = 1;
+          } else {
+            // A number can have only one '.'
+            break;
+          }
         } else if (ch === 0x2D) { // '-'
           // ignore minus signs in the middle of numbers to match
           // Adobe's behavior
           warn('Badly formated number');
-          allDigits = false;
         } else if (ch === 0x45 || ch === 0x65) { // 'E', 'e'
-          floating = true;
-          allDigits = false;
+          // 'E' can be either a scientific notation or the beginning of a new
+          // operator
+          var hasE = true;
+          ch = this.peekChar();
+          if (ch === 0x2B || ch === 0x2D) { // '+', '-'
+            powerValueSign = (ch === 0x2D) ? -1 : 1;
+            this.nextChar(); // Consume the sign character
+          } else if (ch < 0x30 || ch > 0x39) { // '0' - '9'
+            // The 'E' must be the beginning of a new operator
+            break;
+          }
+          eNotation = true;
         } else {
           // the last character doesn't belong to us
           break;
         }
       }
-      var value;
-      if (allDigits) {
-        value = 0;
-        var charCodeOfZero = 48;    // '0'
-        for (var i = 0, ii = strBuf.length; i < ii; i++) {
-          value = value * 10 + (strBuf[i].charCodeAt(0) - charCodeOfZero);
-        }
-      } else {
-        value = parseFloat(strBuf.join(''));
-        if (isNaN(value)) {
-          error('Invalid floating point number: ' + value);
-        }
+
+      if (divideBy !== 0) {
+        baseValue /= divideBy;
       }
-      return value;
+      if (eNotation) {
+        baseValue *= Math.pow(10, powerValueSign * powerValue);
+      }
+      return sign * baseValue;
     },
     getString: function Lexer_getString() {
       var numParen = 1;

test/unit/parser_spec.js

@@ -14,6 +14,30 @@ describe('parser', function() {
       expect(result).toEqual(11.234);
     });
 
+    it('should parse PostScript numbers', function() {
+      var numbers = ['-.002', '34.5', '-3.62', '123.6e10', '1E-5', '-1.', '0.0',
+                    '123', '-98', '43445', '0', '+17'];
+      for (var i=0, ii=numbers.length; i<ii; i++) {
+        var num = numbers[i];
+        var input = new StringStream(num);
+        var lexer = new Lexer(input);
+        var result = lexer.getNumber();
+
+        expect(result).toEqual(parseFloat(num));
+      }
+    });
+
+
+    it('should handle glued numbers and operators', function() {
+      var input = new StringStream('123ET');
+      var lexer = new Lexer(input);
+      var value = lexer.getNumber();
+
+      expect(value).toEqual(123);
+      // The lexer must not have consumed the 'E'
+      expect(lexer.currentChar).toEqual(0x45); // 'E'
+    });
+
     it('should stop parsing strings at the end of stream', function() {
       var input = new StringStream('(1$4)');
       input.getByte = function(super_getByte) {