QStaticByteArrayMatcher 类是编译时版本的 QByteArrayMatcher . 更多...
| 头： | #include <QStaticByteArrayMatcher> |
| CMake: |
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core) |
| qmake: | QT += core |
| qsizetype | indexIn (const QByteArray & haystack , qsizetype from = 0) const |
| qsizetype | indexIn (const char * haystack , qsizetype hlen , qsizetype from = 0) const |
| QByteArray | pattern () const |
| QStaticByteArrayMatcher<N> | qMakeStaticByteArrayMatcher (const char (&)[N] pattern ) |
This class is useful when you have a sequence of bytes that you want to repeatedly match against some byte arrays (perhaps in a loop), or when you want to search for the same sequence of bytes multiple times in the same byte array. Using a matcher object and indexIn () is faster than matching a plain QByteArray with QByteArray::indexOf (), in particular if repeated matching takes place.
不像 QByteArrayMatcher , this class calculates the internal representation at compile-time , so it can even benefit if you are doing one-off byte array matches.
Create the QStaticByteArrayMatcher by calling
qMakeStaticByteArrayMatcher
(), passing it the C string literal you want to search for. Store the return value of that function in a
static const auto
variable, so you don't need to pass the
N
template parameter explicitly:
static const auto matcher = qMakeStaticByteArrayMatcher("needle");
Then call indexIn () on the QByteArray in which you want to search, just like with QByteArrayMatcher .
Since this class is designed to do all the up-front calculations at compile-time, it does not offer a setPattern() method.
另请参阅 QByteArrayMatcher and QStringMatcher .
[noexcept]
qsizetype
QStaticByteArrayMatcher::
indexIn
(const
QByteArray
&
haystack
,
qsizetype
from
= 0) const
Searches the char string haystack , from byte position from (default 0, i.e. from the first byte), for the byte array pattern () that was set in the constructor.
Returns the position where the pattern () matched in haystack , or -1 if no match was found.
[noexcept]
qsizetype
QStaticByteArrayMatcher::
indexIn
(const
char
*
haystack
,
qsizetype
hlen
,
qsizetype
from
= 0) const
Searches the char string haystack , which has length hlen , from byte position from (default 0, i.e. from the first byte), for the byte array pattern () that was set in the constructor.
Returns the position where the pattern () matched in haystack , or -1 if no match was found.
Returns the byte array pattern that this byte array matcher will search for.
另请参阅 QByteArrayMatcher::setPattern ().
[constexpr noexcept]
template <size_t N>
QStaticByteArrayMatcher
<
N
>
qMakeStaticByteArrayMatcher
(const
char
(&)[
N
]
pattern
)
返回
QStaticByteArrayMatcher
with the correct
N
determined automatically from the
pattern
passed.
To take full advantage of this function, assign the result to an
auto
变量：
static const auto matcher = qMakeStaticByteArrayMatcher("needle");