diff options
Diffstat (limited to 'src/corelib/tools/qhash.cpp')
| -rw-r--r-- | src/corelib/tools/qhash.cpp | 33 |
1 files changed, 8 insertions, 25 deletions
diff --git a/src/corelib/tools/qhash.cpp b/src/corelib/tools/qhash.cpp index 5f0b131342..32e9a4269c 100644 --- a/src/corelib/tools/qhash.cpp +++ b/src/corelib/tools/qhash.cpp @@ -755,9 +755,7 @@ void QHashData::checkSanity() Types \c T1 and \c T2 must be supported by qHash(). \note The return type of this function is \e{not} the same as that of - \code - qHash(qMakePair(key.first, key.second), seed); - \endcode + \snippet code/src_corelib_tools_qhash.cpp 29 The two functions use different hashing algorithms; due to binary compatibility constraints, we cannot change the QPair algorithm to match the std::pair one before Qt 6. */ @@ -773,14 +771,10 @@ void QHashData::checkSanity() The return value of this function depends on the order of elements in the range. That means that - \code - {0, 1, 2} - \endcode + \snippet code/src_corelib_tools_qhash.cpp 30 and - \code - {1, 2, 0} - \endcode + \snippet code/src_corelib_tools_qhash.cpp 31 hash to \b{different} values. If order does not matter, for example for hash tables, use qHashRangeCommutative() instead. If you are hashing raw @@ -812,14 +806,10 @@ void QHashData::checkSanity() The return value of this function does not depend on the order of elements in the range. That means that - \code - {0, 1, 2} - \endcode + \snippet code/src_corelib_tools_qhash.cpp 30 and - \code - {1, 2, 0} - \endcode + \snippet code/src_corelib_tools_qhash.cpp 31 hash to the \b{same} values. If order matters, for example, for vectors and arrays, use qHashRange() instead. If you are hashing raw @@ -1100,9 +1090,8 @@ uint qHash(long double key, uint seed) Q_DECL_NOTHROW To avoid this problem, replace \c hash[i] with \c hash.value(i) in the code above. - Internally, QHash uses a hash table to perform lookups. Unlike Qt - 3's \c QDict class, which needed to be initialized with a prime - number, QHash's hash table automatically grows and shrinks to + Internally, QHash uses a hash table to perform lookups. This + hash table automatically grows and shrinks to provide fast lookups without wasting too much memory. You can still control the size of the hash table by calling reserve() if you already know approximately how many items the QHash will @@ -1178,13 +1167,7 @@ uint qHash(long double key, uint seed) Q_DECL_NOTHROW For a key type \c{K}, the qHash function must have one of these signatures: - \code - uint qHash(K key); - uint qHash(const K &key); - - uint qHash(K key, uint seed); - uint qHash(const K &key, uint seed); - \endcode + \snippet code/src_corelib_tools_qhash.cpp 32 The two-arguments overloads take an unsigned integer that should be used to seed the calculation of the hash function. This seed is provided by QHash |