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Merge pull request #5063 from Snuffleupagus/ps-parser-avoid-intermediate-string-creation

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Avoid creating intermediate strings in the PostScriptLexer
This commit is contained in:
Yury Delendik 2014-07-28 15:07:32 -05:00
commit 6038ee7cff
1 changed files with 14 additions and 5 deletions
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19
src/core/ps_parser.js
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@ -137,6 +137,8 @@ var PostScriptLexer = (function PostScriptLexerClosure() {
function PostScriptLexer(stream) { function PostScriptLexer(stream) {
this.stream = stream; this.stream = stream;
this.nextChar(); this.nextChar();
this.strBuf = [];
} }
PostScriptLexer.prototype = { PostScriptLexer.prototype = {
nextChar: function PostScriptLexer_nextChar() { nextChar: function PostScriptLexer_nextChar() {
@ -177,11 +179,15 @@ var PostScriptLexer = (function PostScriptLexerClosure() {
return PostScriptToken.RBRACE; return PostScriptToken.RBRACE;
} }
// operator // operator
var str = String.fromCharCode(ch); var strBuf = this.strBuf;
strBuf.length = 0;
strBuf[0] = String.fromCharCode(ch);
while ((ch = this.nextChar()) >= 0 && // and 'A'-'Z', 'a'-'z' while ((ch = this.nextChar()) >= 0 && // and 'A'-'Z', 'a'-'z'
((ch >= 0x41 && ch <= 0x5A) || (ch >= 0x61 && ch <= 0x7A))) { ((ch >= 0x41 && ch <= 0x5A) || (ch >= 0x61 && ch <= 0x7A))) {
str += String.fromCharCode(ch); strBuf.push(String.fromCharCode(ch));
} }
var str = strBuf.join('');
switch (str.toLowerCase()) { switch (str.toLowerCase()) {
case 'if': case 'if':
return PostScriptToken.IF; return PostScriptToken.IF;
@ -193,16 +199,19 @@ var PostScriptLexer = (function PostScriptLexerClosure() {
}, },
getNumber: function PostScriptLexer_getNumber() { getNumber: function PostScriptLexer_getNumber() {
var ch = this.currentChar; var ch = this.currentChar;
var str = String.fromCharCode(ch); var strBuf = this.strBuf;
strBuf.length = 0;
strBuf[0] = String.fromCharCode(ch);
while ((ch = this.nextChar()) >= 0) { while ((ch = this.nextChar()) >= 0) {
if ((ch >= 0x30 && ch <= 0x39) || // '0'-'9' if ((ch >= 0x30 && ch <= 0x39) || // '0'-'9'
ch === 0x2D || ch === 0x2E) { // '-', '.' ch === 0x2D || ch === 0x2E) { // '-', '.'
str += String.fromCharCode(ch); strBuf.push(String.fromCharCode(ch));
} else { } else {
break; break;
} }
} }
var value = parseFloat(str); var value = parseFloat(strBuf.join(''));
if (isNaN(value)) { if (isNaN(value)) {
error('Invalid floating point number: ' + value); error('Invalid floating point number: ' + value);
} }