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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Inkscape::Util::ptr_shared<T> - like T const *, but stronger.
* Used to hold c-style strings for objects that are managed by the gc.
*
* Authors:
* MenTaLguY <mental@rydia.net>
*
* Copyright (C) 2006 MenTaLguY
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#ifndef SEEN_INKSCAPE_UTIL_SHARE_H
#define SEEN_INKSCAPE_UTIL_SHARE_H
#include "inkgc/gc-core.h"
#include <cstring>
#include <cstddef>
namespace Inkscape {
namespace Util {
class ptr_shared {
public:
ptr_shared() : _string(nullptr) {}
ptr_shared(ptr_shared const &other) = default;
operator char const *() const { return _string; }
operator bool() const { return _string; }
char const *pointer() const { return _string; }
char const &operator[](int i) const { return _string[i]; }
ptr_shared operator+(int i) const {
return share_unsafe(_string+i);
}
ptr_shared operator-(int i) const {
return share_unsafe(_string-i);
}
//WARNING: No bounds checking in += and -= functions. Moving the pointer
//past the end of the string and then back could probably cause the garbage
//collector to deallocate the string inbetween, as there's temporary no
//valid reference pointing into the allocated space.
ptr_shared &operator+=(int i) {
_string += i;
return *this;
}
ptr_shared &operator-=(int i) {
_string -= i;
return *this;
}
std::ptrdiff_t operator-(ptr_shared const &other) {
return _string - other._string;
}
ptr_shared &operator=(ptr_shared const &other) = default;
bool operator==(ptr_shared const &other) const {
return _string == other._string;
}
bool operator!=(ptr_shared const &other) const {
return _string != other._string;
}
bool operator>(ptr_shared const &other) const {
return _string > other._string;
}
bool operator<(ptr_shared const &other) const {
return _string < other._string;
}
friend ptr_shared share_unsafe(char const *string);
private:
ptr_shared(char const *string) : _string(string) {}
static ptr_shared share_unsafe(char const *string) {
return ptr_shared(string);
}
//This class (and code using it) assumes that it never has to free this
//pointer, and that the memory it points to will not be freed as long as a
//ptr_shared pointing to it exists.
char const *_string;
};
ptr_shared share_string(char const *string);
ptr_shared share_string(char const *string, std::size_t length);
inline ptr_shared share_unsafe(char const *string) {
return ptr_shared::share_unsafe(string);
}
//TODO: Do we need this function?
inline ptr_shared share_static_string(char const *string) {
return share_unsafe(string);
}
}
}
#endif
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
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