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source: code/branches/core2/src/util/MultiTypeString.cc @ 1001

Last change on this file since 1001 was 1001, checked in by landauf, 16 years ago

ok, be aware, here comes a big one. people with weak nerves should probably better look away or take some serious drugs.
this update includes partial and explicit class template specialization, partial and explicit specialized template function overloading, template meta programming and a simple typecast.
yeah right, a typecast. but let me explain the whole story from the beginning.

it all started with a simple problem: i had a double in a MultiType and wanted a float, but i always got 0. what was the problem? the conversion 'MultiType to anyting' was handled by the Converter class in util/Convert.h and the Converter was specialized for strings, multitypes, vectors and so on, but not for int, float, bool, …
so i've first wanted to implement a typecast as default, but this was a bad idea because it doesn't work for almost every generic type.
implementing an explicit specialization for every possible pair of primitives (did you ever happened to use an unsigned short? or a long double? no? ignorants :D) would have been a simple but ugly solution.
but there were other problems: if there's a rule to convert a string into anything and another rule to convert anything into an int - what happens if you want to convert a string into an int? compiler error! …ambiguous partial template specialization.
so i've spent days and nights to find a solution. this is my 5th try or so and i'm still really unsure if it works, but it's the first version i want to commit to have at least a backup.
if you're interested in looking at the code you better wait until i've cleaned up the whole thing, it's a real mess. and i want to do further tests, but now i'm tired. good night ;)

File size: 5.3 KB
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1/*
2 *   ORXONOX - the hottest 3D action shooter ever to exist
3 *
4 *
5 *   License notice:
6 *
7 *   This program is free software; you can redistribute it and/or
8 *   modify it under the terms of the GNU General Public License
9 *   as published by the Free Software Foundation; either version 2
10 *   of the License, or (at your option) any later version.
11 *
12 *   This program is distributed in the hope that it will be useful,
13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 *   GNU General Public License for more details.
16 *
17 *   You should have received a copy of the GNU General Public License
18 *   along with this program; if not, write to the Free Software
19 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
20 *
21 *   Author:
22 *      Fabian 'x3n' Landau
23 *   Co-authors:
24 *      ...
25 *
26 *   Inspiration: MultiType by Benjamin Grauer
27 */
28
29#include "MultiTypeString.h"
30#include "Convert.h"
31
32MultiTypeString::MultiTypeString(MultiType type) : MultiTypePrimitive(type)
33{
34    // Nothing to do for string and xml-element
35}
36
37bool MultiTypeString::operator==(const MultiTypeString& mts) const
38{
39    if (!MultiTypePrimitive::operator==(mts) && this->type_ == mts.type_)
40    {
41        if (this->type_ == MT_constchar)
42            return (this->string_ == mts.string_);
43        else if (this->type_ == MT_string)
44            return (this->string_ == mts.string_);
45    }
46
47    return false;
48}
49
50bool MultiTypeString::operator!=(const MultiTypeString& mts) const
51{
52    if (MultiTypePrimitive::operator==(mts) && this->type_ == mts.type_)
53    {
54        if (this->type_ == MT_constchar)
55            return (this->string_ != mts.string_);
56        else if (this->type_ == MT_string)
57            return (this->string_ != mts.string_);
58    }
59
60    return true;
61}
62
63MultiTypeString::operator void*() const
64{ return (this->type_ == MT_void) ? this->value_.void_ : getConvertedValue<MultiTypeString, void*>(*this, 0); }
65MultiTypeString::operator int() const
66{ return (this->type_ == MT_int) ? this->value_.int_ : getConvertedValue<MultiTypeString, int>(*this, 0); }
67MultiTypeString::operator unsigned int() const
68{ return (this->type_ == MT_uint) ? this->value_.uint_ : getConvertedValue<MultiTypeString, unsigned int>(*this, 0); }
69MultiTypeString::operator char() const
70{ return (this->type_ == MT_char) ? this->value_.char_ : getConvertedValue<MultiTypeString, char>(*this, 0); }
71MultiTypeString::operator unsigned char() const
72{ return (this->type_ == MT_uchar) ? this->value_.uchar_ : getConvertedValue<MultiTypeString, unsigned char>(*this, 0); }
73MultiTypeString::operator short() const
74{ return (this->type_ == MT_short) ? this->value_.short_ : getConvertedValue<MultiTypeString, short>(*this, 0); }
75MultiTypeString::operator unsigned short() const
76{ return (this->type_ == MT_ushort) ? this->value_.ushort_ : getConvertedValue<MultiTypeString, unsigned short>(*this, 0); }
77MultiTypeString::operator long() const
78{ return (this->type_ == MT_long) ? this->value_.long_ : getConvertedValue<MultiTypeString, long>(*this, 0); }
79MultiTypeString::operator unsigned long() const
80{ return (this->type_ == MT_ulong) ? this->value_.ulong_ : getConvertedValue<MultiTypeString, unsigned long>(*this, 0); }
81MultiTypeString::operator float() const
82{ return (this->type_ == MT_float) ? this->value_.float_ : getConvertedValue<MultiTypeString, float>(*this, 0); }
83MultiTypeString::operator double() const
84{ return (this->type_ == MT_double) ? this->value_.double_ : getConvertedValue<MultiTypeString, double>(*this, 0); }
85MultiTypeString::operator long double() const
86{ return (this->type_ == MT_longdouble) ? this->value_.longdouble_ : getConvertedValue<MultiTypeString, long double>(*this, 0); }
87MultiTypeString::operator bool() const
88{ return (this->type_ == MT_bool) ? this->value_.bool_ : getConvertedValue<MultiTypeString, bool>(*this, 0); }
89MultiTypeString::operator std::string() const
90{ return (this->type_ == MT_string) ? this->string_ : getConvertedValue<MultiTypeString, std::string>(*this); }
91MultiTypeString::operator const char*() const
92{ return ((this->type_ == MT_constchar) ? this->string_ : getConvertedValue<MultiTypeString, std::string>(*this)).c_str(); }
93
94void MultiTypeString::setValue(const MultiTypeString& mts)
95{
96    MultiTypePrimitive::setValue(mts);
97    this->string_ = mts.string_;
98}
99
100std::string MultiTypeString::getTypename() const
101{
102    if (this->type_ == MT_constchar)
103        return "string";
104    else if (this->type_ == MT_string)
105        return "string";
106    else
107        return MultiTypePrimitive::getTypename();
108}
109
110std::string MultiTypeString::toString() const
111{
112    std::string output;
113
114    if (this->type_ == MT_constchar)
115        return this->string_;
116    else if (this->type_ == MT_string)
117        return this->string_;
118    else
119        return MultiTypePrimitive::toString();
120
121    return output;
122}
123
124bool MultiTypeString::fromString(const std::string value)
125{
126    if (this->type_ == MT_constchar)
127        this->string_ = value;
128    else if (this->type_ == MT_string)
129        this->string_ = value;
130    else
131        return MultiTypePrimitive::fromString(value);
132
133    return true;
134}
135
136std::ostream& operator<<(std::ostream& out, MultiTypeString& mts)
137{
138    out << mts.toString();
139    return out;
140}
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