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Closure Compiler is a JavaScript optimizing compiler. It parses your
JavaScript, analyzes it, removes dead code and rewrites and minimizes
what's left. It also checks syntax, variable references, and types, and
warns about common JavaScript pitfalls. It is used in many of Google's
JavaScript apps, including Gmail, Google Web Search, Google Maps, and
Google Docs.
/*
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Rhino code, released
* May 6, 1999.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1997-2000
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Patrick Beard
* Norris Boyd
* Igor Bukanov
* Ethan Hugg
* Roger Lawrence
* Terry Lucas
* Frank Mitchell
* Milen Nankov
* Andrew Wason
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License Version 2 or later (the "GPL"), in which
* case the provisions of the GPL are applicable instead of those above. If
* you wish to allow use of your version of this file only under the terms of
* the GPL and not to allow others to use your version of this file under the
* MPL, indicate your decision by deleting the provisions above and replacing
* them with the notice and other provisions required by the GPL. If you do
* not delete the provisions above, a recipient may use your version of this
* file under either the MPL or the GPL.
*
* ***** END LICENSE BLOCK ***** */
package com.google.javascript.rhino;
import java.text.MessageFormat;
import java.util.Locale;
import java.util.ResourceBundle;
/**
* This is the class that implements the runtime.
*
*/
public class ScriptRuntime {
/**
* No instances should be created.
*/
protected ScriptRuntime() {
}
// It is public so NativeRegExp can access it .
public static boolean isJSLineTerminator(int c) {
// Optimization for faster check for eol character:
// they do not have 0xDFD0 bits set
if ((c & 0xDFD0) != 0) {
return false;
}
return c == '\n' || c == '\r' || c == 0x2028 || c == 0x2029;
}
// Can not use Double.NaN defined as 0.0d / 0.0 as under the Microsoft VM,
// versions 2.01 and 3.0P1, that causes some uses (returns at least) of
// Double.NaN to be converted to 1.0.
// So we use ScriptRuntime.NaN instead of Double.NaN.
public static final double
NaN = Double.longBitsToDouble(0x7ff8000000000000L);
// A similar problem exists for negative zero.
public static final double
negativeZero = Double.longBitsToDouble(0x8000000000000000L);
/*
* Helper function for toNumber, parseInt, and TokenStream.getToken.
*/
@SuppressWarnings("fallthrough")
static double stringToNumber(String s, int start, int radix) {
char digitMax = '9';
char lowerCaseBound = 'a';
char upperCaseBound = 'A';
int len = s.length();
if (radix < 10) {
digitMax = (char) ('0' + radix - 1);
}
if (radix > 10) {
lowerCaseBound = (char) ('a' + radix - 10);
upperCaseBound = (char) ('A' + radix - 10);
}
int end;
double sum = 0.0;
for (end=start; end < len; end++) {
char c = s.charAt(end);
int newDigit;
if ('0' <= c && c <= digitMax)
newDigit = c - '0';
else if ('a' <= c && c < lowerCaseBound)
newDigit = c - 'a' + 10;
else if ('A' <= c && c < upperCaseBound)
newDigit = c - 'A' + 10;
else
break;
sum = sum*radix + newDigit;
}
if (start == end) {
return NaN;
}
if (sum >= 9007199254740992.0) {
if (radix == 10) {
/* If we're accumulating a decimal number and the number
* is >= 2^53, then the result from the repeated multiply-add
* above may be inaccurate. Call Java to get the correct
* answer.
*/
try {
return Double.valueOf(s.substring(start, end)).doubleValue();
} catch (NumberFormatException nfe) {
return NaN;
}
} else if (radix == 2 || radix == 4 || radix == 8 ||
radix == 16 || radix == 32) {
/* The number may also be inaccurate for one of these bases.
* This happens if the addition in value*radix + digit causes
* a round-down to an even least significant mantissa bit
* when the first dropped bit is a one. If any of the
* following digits in the number (which haven't been added
* in yet) are nonzero then the correct action would have
* been to round up instead of down. An example of this
* occurs when reading the number 0x1000000000000081, which
* rounds to 0x1000000000000000 instead of 0x1000000000000100.
*/
int bitShiftInChar = 1;
int digit = 0;
final int SKIP_LEADING_ZEROS = 0;
final int FIRST_EXACT_53_BITS = 1;
final int AFTER_BIT_53 = 2;
final int ZEROS_AFTER_54 = 3;
final int MIXED_AFTER_54 = 4;
int state = SKIP_LEADING_ZEROS;
int exactBitsLimit = 53;
double factor = 0.0;
boolean bit53 = false;
// bit54 is the 54th bit (the first dropped from the mantissa)
boolean bit54 = false;
for (;;) {
if (bitShiftInChar == 1) {
if (start == end)
break;
digit = s.charAt(start++);
if ('0' <= digit && digit <= '9')
digit -= '0';
else if ('a' <= digit && digit <= 'z')
digit -= 'a' - 10;
else
digit -= 'A' - 10;
bitShiftInChar = radix;
}
bitShiftInChar >>= 1;
boolean bit = (digit & bitShiftInChar) != 0;
switch (state) {
case SKIP_LEADING_ZEROS:
if (bit) {
--exactBitsLimit;
sum = 1.0;
state = FIRST_EXACT_53_BITS;
}
break;
case FIRST_EXACT_53_BITS:
sum *= 2.0;
if (bit)
sum += 1.0;
--exactBitsLimit;
if (exactBitsLimit == 0) {
bit53 = bit;
state = AFTER_BIT_53;
}
break;
case AFTER_BIT_53:
bit54 = bit;
factor = 2.0;
state = ZEROS_AFTER_54;
break;
case ZEROS_AFTER_54:
if (bit) {
state = MIXED_AFTER_54;
}
// fallthrough
case MIXED_AFTER_54:
factor *= 2;
break;
}
}
switch (state) {
case SKIP_LEADING_ZEROS:
sum = 0.0;
break;
case FIRST_EXACT_53_BITS:
case AFTER_BIT_53:
// do nothing
break;
case ZEROS_AFTER_54:
// x1.1 -> x1 + 1 (round up)
// x0.1 -> x0 (round down)
if (bit54 & bit53)
sum += 1.0;
sum *= factor;
break;
case MIXED_AFTER_54:
// x.100...1.. -> x + 1 (round up)
// x.0anything -> x (round down)
if (bit54)
sum += 1.0;
sum *= factor;
break;
}
}
/* We don't worry about inaccurate numbers for any other base. */
}
return sum;
}
public static String escapeString(String s) {
return escapeString(s, '"');
}
/**
* For escaping strings printed by object and array literals; not quite
* the same as 'escape.'
*/
public static String escapeString(String s, char escapeQuote) {
if (!(escapeQuote == '"' || escapeQuote == '\'')) {
throw new IllegalStateException("unexpected quote char:" + escapeQuote);
}
StringBuffer sb = null;
for(int i = 0, L = s.length(); i != L; ++i) {
int c = s.charAt(i);
if (' ' <= c && c <= '~' && c != escapeQuote && c != '\\') {
// an ordinary print character (like C isprint()) and not "
// or \ .
if (sb != null) {
sb.append((char)c);
}
continue;
}
if (sb == null) {
sb = new StringBuffer(L + 3);
sb.append(s);
sb.setLength(i);
}
int escape = -1;
switch (c) {
case '\b': escape = 'b'; break;
case '\f': escape = 'f'; break;
case '\n': escape = 'n'; break;
case '\r': escape = 'r'; break;
case '\t': escape = 't'; break;
case 0xb: escape = 'v'; break; // Java lacks \v.
case ' ': escape = ' '; break;
case '\\': escape = '\\'; break;
}
if (escape >= 0) {
// an \escaped sort of character
sb.append('\\');
sb.append((char)escape);
} else if (c == escapeQuote) {
sb.append('\\');
sb.append(escapeQuote);
} else {
int hexSize;
if (c < 256) {
// 2-digit hex
sb.append("\\x");
hexSize = 2;
} else {
// Unicode.
sb.append("\\u");
hexSize = 4;
}
// append hexadecimal form of c left-padded with 0
for (int shift = (hexSize - 1) * 4; shift >= 0; shift -= 4) {
int digit = 0xf & (c >> shift);
int hc = (digit < 10) ? '0' + digit : 'a' - 10 + digit;
sb.append((char)hc);
}
}
}
return (sb == null) ? s : sb.toString();
}
static boolean isValidIdentifierName(String s) {
int L = s.length();
if (L == 0)
return false;
if (!Character.isJavaIdentifierStart(s.charAt(0)))
return false;
for (int i = 1; i != L; ++i) {
if (!Character.isJavaIdentifierPart(s.charAt(i)))
return false;
}
return !TokenStream.isKeyword(s);
}
/**
* If str is a decimal presentation of Uint32 value, return it as long.
* Othewise return -1L;
*/
public static long testUint32String(String str) {
// The length of the decimal string representation of
// UINT32_MAX_VALUE, 4294967296
final int MAX_VALUE_LENGTH = 10;
int len = str.length();
if (1 <= len && len <= MAX_VALUE_LENGTH) {
int c = str.charAt(0);
c -= '0';
if (c == 0) {
// Note that 00,01 etc. are not valid Uint32 presentations
return (len == 1) ? 0L : -1L;
}
if (1 <= c && c <= 9) {
long v = c;
for (int i = 1; i != len; ++i) {
c = str.charAt(i) - '0';
if (!(0 <= c && c <= 9)) {
return -1;
}
v = 10 * v + c;
}
// Check for overflow
if ((v >>> 32) == 0) {
return v;
}
}
}
return -1;
}
static boolean isSpecialProperty(String s) {
return s.equals("__proto__") || s.equals("__parent__");
}
// ------------------
// Statements
// ------------------
public static String getMessage0(String messageId) {
return getMessage(messageId, null);
}
public static String getMessage1(String messageId, Object arg1) {
Object[] arguments = {arg1};
return getMessage(messageId, arguments);
}
/* OPT there's a noticable delay for the first error! Maybe it'd
* make sense to use a ListResourceBundle instead of a properties
* file to avoid (synchronized) text parsing.
*/
public static String getMessage(String messageId, Object[] arguments) {
final String defaultResource
= "rhino_ast.java.com.google.javascript.rhino.Messages";
Locale locale = Locale.getDefault();
// ResourceBundle does cacheing.
ResourceBundle rb = ResourceBundle.getBundle(defaultResource, locale);
String formatString;
try {
formatString = rb.getString(messageId);
} catch (java.util.MissingResourceException mre) {
throw new RuntimeException
("no message resource found for message property "+ messageId);
}
/*
* It's OK to format the string, even if 'arguments' is null;
* we need to format it anyway, to make double ''s collapse to
* single 's.
*/
// TODO: MessageFormat is not available on pJava
MessageFormat formatter = new MessageFormat(formatString);
return formatter.format(arguments);
}
}