diff options
| -rw-r--r-- | src/corelib/tools/qbytearray.cpp | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp index 8d38e4c..033da90 100644 --- a/src/corelib/tools/qbytearray.cpp +++ b/src/corelib/tools/qbytearray.cpp @@ -850,7 +850,7 @@ QByteArray::Data QByteArray::shared_empty = { Q_BASIC_ATOMIC_INITIALIZER(1), This operation takes \l{constant time}, because QByteArray is \l{implicitly shared}. This makes returning a QByteArray from a function very fast. If a shared instance is modified, it will be - copied (copy-on-write), and that takes \l{linear time}. + copied (copy-on-write), taking \l{linear time}. \sa operator=() */ @@ -1186,10 +1186,18 @@ void QByteArray::chop(int n) Example: \snippet doc/src/snippets/code/src_corelib_tools_qbytearray.cpp 12 - This operation is typically very fast (\l{constant time}), - because QByteArray preallocates extra space at the end of the - character data so it can grow without reallocating the entire - data each time. + Note: QByteArray is an \l{implicitly shared} class. Consequently, + if \e this is an empty QByteArray, then \e this will just share + the data held in \a ba. In this case, no copying of data is done, + taking \l{constant time}. If a shared instance is modified, it will + be copied (copy-on-write), taking \l{linear time}. + + If \e this is not an empty QByteArray, a deep copy of the data is + performed, taking \l{linear time}. + + This operation typically does not suffer from allocation overhead, + because QByteArray preallocates extra space at the end of the data + so that it may grow without reallocating for each append operation. \sa append(), prepend() */ @@ -1474,7 +1482,12 @@ QByteArray QByteArray::nulTerminated() const Note: QByteArray is an \l{implicitly shared} class. Consequently, if \e this is an empty QByteArray, then \e this will just share - the data held in \a ba. In this case, no copying of data is done. + the data held in \a ba. In this case, no copying of data is done, + taking \l{constant time}. If a shared instance is modified, it will + be copied (copy-on-write), taking \l{linear time}. + + If \e this is not an empty QByteArray, a deep copy of the data is + performed, taking \l{linear time}. \sa append(), insert() */ @@ -1547,14 +1560,18 @@ QByteArray &QByteArray::prepend(char ch) This is the same as insert(size(), \a ba). - This operation is typically very fast (\l{constant time}), - because QByteArray preallocates extra space at the end of the - character data so it can grow without reallocating the entire - data each time. - Note: QByteArray is an \l{implicitly shared} class. Consequently, if \e this is an empty QByteArray, then \e this will just share - the data held in \a ba. In this case, no copying of data is done. + the data held in \a ba. In this case, no copying of data is done, + taking \l{constant time}. If a shared instance is modified, it will + be copied (copy-on-write), taking \l{linear time}. + + If \e this is not an empty QByteArray, a deep copy of the data is + performed, taking \l{linear time}. + + This operation typically does not suffer from allocation overhead, + because QByteArray preallocates extra space at the end of the data + so that it may grow without reallocating for each append operation. \sa operator+=(), prepend(), insert() */ |