qt/api/qscriptconverter_p.h

   1 /*
   2     Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
   3
   4     This library is free software; you can redistribute it and/or
   5     modify it under the terms of the GNU Library General Public
   6     License as published by the Free Software Foundation; either
   7     version 2 of the License, or (at your option) any later version.
   8
   9     This library is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12     Library General Public License for more details.
  13
  14     You should have received a copy of the GNU Library General Public License
  15     along with this library; see the file COPYING.LIB.  If not, write to
  16     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17     Boston, MA 02110-1301, USA.
  18 */
  19
  20 #ifndef qscriptconverter_p_h
  21 #define qscriptconverter_p_h
  22
  23 #include <JavaScriptCore/JavaScript.h>
  24 #include <QtCore/qnumeric.h>
  25 #include <QtCore/qstring.h>
  26 #include <QtCore/qvarlengtharray.h>
  27
  28 extern char *qdtoa(double d, int mode, int ndigits, int *decpt, int *sign, char **rve, char **digits_str);
  29
  30 /*
  31   \internal
  32   \class QScriptConverter
  33   QScriptValue and QScriptEngine helper class. This class's responsibility is to convert values
  34   between JS values and Qt/C++ values.
  35
  36   This is a nice way to inline these functions in both QScriptValue and QScriptEngine.
  37 */
  38 class QScriptConverter {
  39 public:
  40     static quint32 toArrayIndex(const JSStringRef jsstring)
  41     {
  42         // FIXME this function should be exported by JSC C API.
  43         QString qstring = toString(jsstring);
  44
  45         bool ok;
  46         quint32 idx = qstring.toUInt(&ok);
  47         if (!ok || toString(idx) != qstring)
  48             idx = 0xffffffff;
  49
  50         return idx;
  51     }
  52
  53     static QString toString(const JSStringRef str)
  54     {
  55         return QString(reinterpret_cast<const QChar*>(JSStringGetCharactersPtr(str)), JSStringGetLength(str));
  56     }
  57     static JSStringRef toString(const QString& str)
  58     {
  59         return JSStringCreateWithUTF8CString(str.toUtf8().constData());
  60     }
  61     static JSStringRef toString(const char* str)
  62     {
  63         return JSStringCreateWithUTF8CString(str);
  64     }
  65     static QString toString(double value)
  66     {
  67         // FIXME this should be easier. The ideal fix is to create
  68         // a new function in JSC C API which could cover the functionality.
  69
  70         if (qIsNaN(value))
  71             return QString::fromLatin1("NaN");
  72         if (qIsInf(value))
  73             return QString::fromLatin1(value < 0 ? "-Infinity" : "Infinity");
  74         if (!value)
  75             return QString::fromLatin1("0");
  76
  77         QVarLengthArray<char, 25> buf;
  78         int decpt;
  79         int sign;
  80         char* result = 0;
  81         char* endresult;
  82         (void)qdtoa(value, 0, 0, &decpt, &sign, &endresult, &result);
  83
  84         if (!result)
  85             return QString();
  86
  87         int resultLen = endresult - result;
  88         if (decpt <= 0 && decpt > -6) {
  89             buf.resize(-decpt + 2 + sign);
  90             qMemSet(buf.data(), '0', -decpt + 2 + sign);
  91             if (sign) // fix the sign.
  92                 buf[0] = '-';
  93             buf[sign + 1] = '.';
  94             buf.append(result, resultLen);
  95         } else {
  96             if (sign)
  97                 buf.append('-');
  98             int length = buf.size() - sign + resultLen;
  99             if (decpt <= 21 && decpt > 0) {
 100                 if (length <= decpt) {
 101                     const char* zeros = "0000000000000000000000000";
 102                     buf.append(result, resultLen);
 103                     buf.append(zeros, decpt - length);
 104                 } else {
 105                     buf.append(result, decpt);
 106                     buf.append('.');
 107                     buf.append(result + decpt, resultLen - decpt);
 108                 }
 109             } else if (result[0] >= '0' && result[0] <= '9') {
 110                 if (length > 1) {
 111                     buf.append(result, 1);
 112                     buf.append('.');
 113                     buf.append(result + 1, resultLen - 1);
 114                 } else
 115                     buf.append(result, resultLen);
 116                 buf.append('e');
 117                 buf.append(decpt >= 0 ? '+' : '-');
 118                 int e = qAbs(decpt - 1);
 119                 if (e >= 100)
 120                     buf.append('0' + e / 100);
 121                 if (e >= 10)
 122                     buf.append('0' + (e % 100) / 10);
 123                 buf.append('0' + e % 10);
 124             }
 125         }
 126         free(result);
 127         buf.append(0);
 128         return QString::fromLatin1(buf.constData());
 129     }
 130 };
 131
 132 #endif // qscriptconverter_p_h