From ad35a41739c8e1fb6db62ed37b764448b2e59ece Mon Sep 17 00:00:00 2001 From: Lars Knoll Date: Mon, 11 Jul 2011 23:16:58 +0200 Subject: Refactor QByteArray to allow for const data Similar refactoring as done for QString. Make shared_null read-only, and add support for compile time generated QByteArrayData. Add support for properly reserving capacity. Change-Id: Ie4c41d4caac7b3b4bb1aef40c1c860a30b82edb8 Reviewed-on: http://codereview.qt.nokia.com/1484 Reviewed-by: Qt Sanity Bot Reviewed-by: Olivier Goffart --- src/corelib/tools/qbytearray.h | 132 +++++++++++++++++++++++++++++------------ 1 file changed, 93 insertions(+), 39 deletions(-) (limited to 'src/corelib/tools/qbytearray.h') diff --git a/src/corelib/tools/qbytearray.h b/src/corelib/tools/qbytearray.h index 26cf2af59c..dbac302d05 100644 --- a/src/corelib/tools/qbytearray.h +++ b/src/corelib/tools/qbytearray.h @@ -42,7 +42,7 @@ #ifndef QBYTEARRAY_H #define QBYTEARRAY_H -#include +#include #include #include @@ -119,18 +119,65 @@ class QString; class QDataStream; template class QList; +struct QByteArrayData +{ + QtPrivate::RefCount ref; + int size; + uint alloc : 31; + uint capacityReserved : 1; + union { + qptrdiff offset; // will always work as we add/subtract from a ushort ptr + char d[sizeof(qptrdiff)]; + }; + inline char *data() { return d + sizeof(qptrdiff) + offset; } + inline const char *data() const { return d + sizeof(qptrdiff) + offset; } +}; + +template struct QConstByteArrayData +{ + const QByteArrayData ba; + const char data[n]; +}; + +template struct QConstByteArrayDataPtr +{ + const QConstByteArrayData *ptr; +}; + + +#if defined(Q_COMPILER_LAMBDA) +# define QByteArrayLiteral(str) ([]() { \ + enum { Size = sizeof(str) }; \ + static const QConstByteArrayData qbytearray_literal = \ + { { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, str }; \ + QConstByteArrayDataPtr holder = { &qbytearray_literal }; \ + return holder; }()) + +#elif defined(Q_CC_GNU) +// We need to create a QByteArrayData in the .rodata section of memory +// and the only way to do that is to create a "static const" variable. +// To do that, we need the __extension__ {( )} trick which only GCC supports + +# define QByteArrayLiteral(str) \ + __extension__ ({ \ + enum { Size = sizeof(str) }; \ + static const QConstByteArrayData qbytearray_literal = \ + { { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, str }; \ + QConstByteArrayDataPtr holder = { &qbytearray_literal }; \ + holder; }) +#endif + +#ifndef QByteArrayLiteral +// no lambdas, not GCC, use const char * instead + +# define QByteArrayLiteral(str) (str) +#endif + + class Q_CORE_EXPORT QByteArray { private: - struct Data { - QBasicAtomicInt ref; - int alloc, size; - // ### Qt 5.0: We need to add the missing capacity bit - // (like other tool classes have), to maintain the - // reserved memory on resize. - char *data; - char array[1]; - }; + typedef QByteArrayData Data; public: inline QByteArray(); @@ -330,10 +377,17 @@ public: int length() const { return d->size; } bool isNull() const; + template + inline QByteArray(const QConstByteArrayData &dd) + : d(const_cast(&dd.str)) {} + template + Q_DECL_CONSTEXPR inline QByteArray(QConstByteArrayDataPtr dd) + : d(const_cast(&dd.ptr->ba)) {} + private: operator QNoImplicitBoolCast() const; - static Data shared_null; - static Data shared_empty; + static QConstByteArrayData<1> shared_null; + static QConstByteArrayData<1> shared_empty; Data *d; QByteArray(Data *dd, int /*dummy*/, int /*dummy*/) : d(dd) {} void realloc(int alloc); @@ -348,34 +402,34 @@ public: inline DataPtr &data_ptr() { return d; } }; -inline QByteArray::QByteArray(): d(&shared_null) { d->ref.ref(); } +inline QByteArray::QByteArray(): d(const_cast(&shared_null.ba)) { d->ref.ref(); } inline QByteArray::~QByteArray() { if (!d->ref.deref()) qFree(d); } inline int QByteArray::size() const { return d->size; } inline char QByteArray::at(int i) const -{ Q_ASSERT(i >= 0 && i < size()); return d->data[i]; } +{ Q_ASSERT(i >= 0 && i < size()); return d->data()[i]; } inline char QByteArray::operator[](int i) const -{ Q_ASSERT(i >= 0 && i < size()); return d->data[i]; } +{ Q_ASSERT(i >= 0 && i < size()); return d->data()[i]; } inline char QByteArray::operator[](uint i) const -{ Q_ASSERT(i < uint(size())); return d->data[i]; } +{ Q_ASSERT(i < uint(size())); return d->data()[i]; } inline bool QByteArray::isEmpty() const { return d->size == 0; } #ifndef QT_NO_CAST_FROM_BYTEARRAY inline QByteArray::operator const char *() const -{ return d->data; } +{ return d->data(); } inline QByteArray::operator const void *() const -{ return d->data; } +{ return d->data(); } #endif inline char *QByteArray::data() -{ detach(); return d->data; } +{ detach(); return d->data(); } inline const char *QByteArray::data() const -{ return d->data; } +{ return d->data(); } inline const char *QByteArray::constData() const -{ return d->data; } +{ return d->data(); } inline void QByteArray::detach() -{ if (d->ref != 1 || d->data != d->array) realloc(d->size); } +{ if (d->ref != 1 || d->offset) realloc(d->size); } inline bool QByteArray::isDetached() const { return d->ref == 1; } inline QByteArray::QByteArray(const QByteArray &a) : d(a.d) @@ -385,10 +439,10 @@ inline int QByteArray::capacity() const { return d->alloc; } inline void QByteArray::reserve(int asize) -{ if (d->ref != 1 || asize > d->alloc) realloc(asize); } +{ if (d->ref != 1 || asize > d->alloc) realloc(asize); d->capacityReserved = true; } inline void QByteArray::squeeze() -{ if (d->size < d->alloc) realloc(d->size); } +{ if (d->size < d->alloc) realloc(d->size); d->capacityReserved = false; } class Q_CORE_EXPORT QByteRef { QByteArray &a; @@ -398,25 +452,25 @@ class Q_CORE_EXPORT QByteRef { friend class QByteArray; public: inline operator char() const - { return i < a.d->size ? a.d->data[i] : char(0); } + { return i < a.d->size ? a.d->data()[i] : char(0); } inline QByteRef &operator=(char c) { if (i >= a.d->size) a.expand(i); else a.detach(); - a.d->data[i] = c; return *this; } + a.d->data()[i] = c; return *this; } inline QByteRef &operator=(const QByteRef &c) { if (i >= a.d->size) a.expand(i); else a.detach(); - a.d->data[i] = c.a.d->data[c.i]; return *this; } + a.d->data()[i] = c.a.d->data()[c.i]; return *this; } inline bool operator==(char c) const - { return a.d->data[i] == c; } + { return a.d->data()[i] == c; } inline bool operator!=(char c) const - { return a.d->data[i] != c; } + { return a.d->data()[i] != c; } inline bool operator>(char c) const - { return a.d->data[i] > c; } + { return a.d->data()[i] > c; } inline bool operator>=(char c) const - { return a.d->data[i] >= c; } + { return a.d->data()[i] >= c; } inline bool operator<(char c) const - { return a.d->data[i] < c; } + { return a.d->data()[i] < c; } inline bool operator<=(char c) const - { return a.d->data[i] <= c; } + { return a.d->data()[i] <= c; } }; inline QByteRef QByteArray::operator[](int i) @@ -424,17 +478,17 @@ inline QByteRef QByteArray::operator[](int i) inline QByteRef QByteArray::operator[](uint i) { return QByteRef(*this, i); } inline QByteArray::iterator QByteArray::begin() -{ detach(); return d->data; } +{ detach(); return d->data(); } inline QByteArray::const_iterator QByteArray::begin() const -{ return d->data; } +{ return d->data(); } inline QByteArray::const_iterator QByteArray::constBegin() const -{ return d->data; } +{ return d->data(); } inline QByteArray::iterator QByteArray::end() -{ detach(); return d->data + d->size; } +{ detach(); return d->data() + d->size; } inline QByteArray::const_iterator QByteArray::end() const -{ return d->data + d->size; } +{ return d->data() + d->size; } inline QByteArray::const_iterator QByteArray::constEnd() const -{ return d->data + d->size; } +{ return d->data() + d->size; } inline QByteArray &QByteArray::operator+=(char c) { return append(c); } inline QByteArray &QByteArray::operator+=(const char *s) -- cgit v1.2.3