QByteArray, QString, QStringRef: Add chopped()

We have two functions to get a substring without doing some
calculations involving size():

- mid(p):    mid(p, size() - p)
- right(n) : mid(size() - n, n)

(left does not involve size(), so isn't in that set). What was missing
was a name for

- f(n): mid(0, size() - n)

As an action, it's called chop(), so call the transformation version
chopped().

I made chopped(n), n < 0 or n > size(), undefined, because QString(Ref)
::left() is broken[1], while the QByteArray implementation is not. This
is the only way to get consistent behavior among the three classes.

I's also the correct thing to do.

[1] instead of returning the empty string for negative indexes, it
returns the whole string.

[ChangeLog][QtCore][QString/QStringRef/QByteArray] Added chopped(n), a
const version of chop(n).

Change-Id: I6c2c5b16e0060fa924ced5860f21f2d0f23bd023
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>

1 files changed, 15 insertions, 3 deletions

diff --git a/src/corelib/tools/qbytearray.cpp b/src/corelib/tools/qbytearray.cpp
index c728a05f55..5f42ff0146 100644
--- a/src/corelib/tools/qbytearray.cpp
+++ b/src/corelib/tools/qbytearray.cpp
@@ -2972,7 +2972,7 @@ bool QByteArray::endsWith(char ch) const
     Example:
     \snippet code/src_corelib_tools_qbytearray.cpp 27
 
-    \sa right(), mid(), startsWith(), truncate()
+    \sa startsWith(), right(), mid(), chopped(), chop(), truncate()
 */
 
 QByteArray QByteArray::left(int len)  const
@@ -2994,7 +2994,7 @@ QByteArray QByteArray::left(int len)  const
     Example:
     \snippet code/src_corelib_tools_qbytearray.cpp 28
 
-    \sa endsWith(), left(), mid()
+    \sa endsWith(), left(), mid(), chopped(), chop(), truncate()
 */
 
 QByteArray QByteArray::right(int len) const
@@ -3017,7 +3017,7 @@ QByteArray QByteArray::right(int len) const
     Example:
     \snippet code/src_corelib_tools_qbytearray.cpp 29
 
-    \sa left(), right()
+    \sa left(), right(), chopped(), chop(), truncate()
 */
 
 QByteArray QByteArray::mid(int pos, int len) const
@@ -3041,6 +3041,18 @@ QByteArray QByteArray::mid(int pos, int len) const
 }
 
 /*!
+    \fn QByteArray::chopped(int len) const
+    \since 5.10
+
+    Returns a byte array that contains the leftmost size() - \a len bytes of
+    this byte array.
+
+    \note The behavior is undefined if \a len is negative or greater than size().
+
+    \sa endsWith(), left(), right(), mid(), chop(), truncate().
+*/
+
+/*!
     \fn QByteArray QByteArray::toLower() const
 
     Returns a lowercase copy of the byte array. The bytearray is