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reduce array creation in readString

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Alistair Braidwood 2012-12-19 08:22:44 +00:00 committed by Marijn Haverbeke
parent 5b19196bac
commit 2bad03e654
1 changed files with 17 additions and 15 deletions
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32
acorn.js
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@ -725,15 +725,17 @@
// Read a string value, interpreting backslash-escapes. // Read a string value, interpreting backslash-escapes.
var rs_str = [];
function readString(quote) { function readString(quote) {
tokPos++; tokPos++;
var str = []; rs_str.length = 0;
for (;;) { for (;;) {
if (tokPos >= inputLen) raise(tokStart, "Unterminated string constant"); if (tokPos >= inputLen) raise(tokStart, "Unterminated string constant");
var ch = input.charCodeAt(tokPos); var ch = input.charCodeAt(tokPos);
if (ch === quote) { if (ch === quote) {
++tokPos; ++tokPos;
return finishToken(_string, String.fromCharCode.apply(null, str)); return finishToken(_string, String.fromCharCode.apply(null, rs_str));
} }
if (ch === 92) { // '\' if (ch === 92) { // '\'
ch = input.charCodeAt(++tokPos); ch = input.charCodeAt(++tokPos);
@ -744,28 +746,28 @@
++tokPos; ++tokPos;
if (octal) { if (octal) {
if (strict) raise(tokPos - 2, "Octal literal in strict mode"); if (strict) raise(tokPos - 2, "Octal literal in strict mode");
str.push(parseInt(octal, 8)); rs_str.push(parseInt(octal, 8));
tokPos += octal.length - 1; tokPos += octal.length - 1;
} else { } else {
switch (ch) { switch (ch) {
case 110: str.push(10); break; // 'n' -> '\n' case 110: rs_str.push(10); break; // 'n' -> '\n'
case 114: str.push(13); break; // 'r' -> '\r' case 114: rs_str.push(13); break; // 'r' -> '\r'
case 120: str.push(readHexChar(2)); break; // 'x' case 120: rs_str.push(readHexChar(2)); break; // 'x'
case 117: str.push(readHexChar(4)); break; // 'u' case 117: rs_str.push(readHexChar(4)); break; // 'u'
case 85: str.push(readHexChar(8)); break; // 'U' case 85: rs_str.push(readHexChar(8)); break; // 'U'
case 116: str.push(9); break; // 't' -> '\t' case 116: rs_str.push(9); break; // 't' -> '\t'
case 98: str.push(8); break; // 'b' -> '\b' case 98: rs_str.push(8); break; // 'b' -> '\b'
case 118: str.push(11); break; // 'v' -> '\u000b' case 118: rs_str.push(11); break; // 'v' -> '\u000b'
case 102: str.push(12); break; // 'f' -> '\f' case 102: rs_str.push(12); break; // 'f' -> '\f'
case 48: str.push(0); break; // 0 -> '\0' case 48: rs_str.push(0); break; // 0 -> '\0'
case 13: if (input.charCodeAt(tokPos) === 10) ++tokPos; // '\r\n' case 13: if (input.charCodeAt(tokPos) === 10) ++tokPos; // '\r\n'
case 10: break; // ' \n' case 10: break; // ' \n'
default: str.push(ch); break; default: rs_str.push(ch); break;
} }
} }
} else { } else {
if (ch === 13 || ch === 10 || ch === 8232 || ch === 8329) raise(tokStart, "Unterminated string constant"); if (ch === 13 || ch === 10 || ch === 8232 || ch === 8329) raise(tokStart, "Unterminated string constant");
if (ch !== 92) str.push(ch); // '\' if (ch !== 92) rs_str.push(ch); // '\'
++tokPos; ++tokPos;
} }
} }