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Stringify a define
If you would like to pass a string into a define via the compiler -D directive, but need to use it as if it was a quoted #define, it takes a pair of macros (verified to work on g++ and also Visual Studio):
#define STRINGIFY_IMPL(S) #S #define STRINGIFY(s) STRINGIFY_IMPL(s)
then it can be used like this:
QFile uiFile(":" STRINGIFY(UI_FILE));
and in the .pro file if using Qt:
DEFINES += UI_FILE="some.ui"
so when it's compiled:
g++ foo.cpp -DUI_FILE=some.ui ...
(oh noes, it's DUI!)
Find range of true values in a std::vector<bool>
class Tracker { public: void update(int index, bool value) { if (index < 0) return; if (unsigned(index) >= m_vec.size()) m_vec.resize(index * 2 + 1); m_vec[index] = value; } int firstIndex(bool val) { auto found = std::find(std::begin(m_vec), std::end(m_vec), val); if (found == std::end(m_vec)) return -1; return found - m_vec.begin(); } int lastIndex(bool val) { auto found = std::find(m_vec.rbegin(), m_vec.rend(), true); if (found == m_vec.rend()) return -1; return m_vec.rend() - found; } std::vector<bool> m_vec; };