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#ifndef QBYTEARRAYMATCHER_H
#define QBYTEARRAYMATCHER_H
#include <QtCore/qbytearray.h>
QT_BEGIN_NAMESPACE
class QByteArrayMatcherPrivate;
class Q_CORE_EXPORT QByteArrayMatcher
{
public:
QByteArrayMatcher();
explicit QByteArrayMatcher(const QByteArray &pattern);
explicit QByteArrayMatcher(const char *pattern, int length);
QByteArrayMatcher(const QByteArrayMatcher &other);
~QByteArrayMatcher();
QByteArrayMatcher &operator=(const QByteArrayMatcher &other);
void setPattern(const QByteArray &pattern);
int indexIn(const QByteArray &ba, int from = 0) const;
int indexIn(const char *str, int len, int from = 0) const;
inline QByteArray pattern() const
{
if (q_pattern.isNull())
return QByteArray(reinterpret_cast<const char*>(p.p), p.l);
return q_pattern;
}
private:
QByteArrayMatcherPrivate *d;
QByteArray q_pattern;
struct Data {
uchar q_skiptable[256];
const uchar *p;
int l;
};
union {
uint dummy[256];
Data p;
};
};
class QStaticByteArrayMatcherBase
{
Q_DECL_ALIGN(16)
struct Skiptable {
uchar data[256];
} m_skiptable;
protected:
explicit Q_DECL_RELAXED_CONSTEXPR QStaticByteArrayMatcherBase(const char *pattern, uint n) Q_DECL_NOTHROW
: m_skiptable(generate(pattern, n)) {}
// compiler-generated copy/more ctors/assignment operators are ok!
// compiler-generated dtor is ok!
Q_CORE_EXPORT int indexOfIn(const char *needle, uint nlen, const char *haystack, int hlen, int from) const Q_DECL_NOTHROW;
private:
static Q_DECL_RELAXED_CONSTEXPR Skiptable generate(const char *pattern, uint n) Q_DECL_NOTHROW
{
const auto uchar_max = (std::numeric_limits<uchar>::max)();
uchar max = n > uchar_max ? uchar_max : n;
Skiptable table = {
// this verbose initialization code aims to avoid some opaque error messages
// even on powerful compilers such as GCC 5.3. Even though for GCC a loop
// format can be found that v5.3 groks, it's probably better to go with this
// for the time being:
{
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
max, max, max, max, max, max, max, max, max, max, max, max, max, max, max, max,
}
};
pattern += n - max;
while (max--)
table.data[uchar(*pattern++)] = max;
return table;
}
};
QT_WARNING_PUSH
QT_WARNING_DISABLE_MSVC(4351) // MSVC 2013: "new behavior: elements of array ... will be default initialized"
// remove once we drop MSVC 2013 support
template <uint N>
class QStaticByteArrayMatcher : QStaticByteArrayMatcherBase
{
char m_pattern[N];
Q_STATIC_ASSERT_X(N > 2, "QStaticByteArrayMatcher makes no sense for finding a single-char pattern");
public:
explicit Q_DECL_RELAXED_CONSTEXPR QStaticByteArrayMatcher(const char (&patternToMatch)[N]) Q_DECL_NOTHROW
: QStaticByteArrayMatcherBase(patternToMatch, N - 1), m_pattern()
{
for (uint i = 0; i < N; ++i)
m_pattern[i] = patternToMatch[i];
}
int indexIn(const QByteArray &haystack, int from = 0) const Q_DECL_NOTHROW
{ return this->indexOfIn(m_pattern, N - 1, haystack.data(), haystack.size(), from); }
int indexIn(const char *haystack, int hlen, int from = 0) const Q_DECL_NOTHROW
{ return this->indexOfIn(m_pattern, N - 1, haystack, hlen, from); }
QByteArray pattern() const { return QByteArray(m_pattern, int(N - 1)); }
};
QT_WARNING_POP
template <uint N>
Q_DECL_RELAXED_CONSTEXPR QStaticByteArrayMatcher<N> qMakeStaticByteArrayMatcher(const char (&pattern)[N]) Q_DECL_NOTHROW
{ return QStaticByteArrayMatcher<N>(pattern); }
QT_END_NAMESPACE
#endif // QBYTEARRAYMATCHER_H