From 17504a7b32a71e91ceae37cd8023ae0557b45cb6 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Wed, 21 Oct 2015 22:21:03 +0200
Subject: [PATCH] QTextStream: use new QString::resize(int, QChar) for padding

Change-Id: I17c90ea32614c45f038f5f3386749dfa74bad438
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
---
 src/corelib/io/qtextstream.cpp | 42 ++++++++++++++++++++--------------
 src/corelib/io/qtextstream_p.h |  4 +---
 2 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/src/corelib/io/qtextstream.cpp b/src/corelib/io/qtextstream.cpp
index adf9e1aa55b..9f0a8c08ede 100644
--- a/src/corelib/io/qtextstream.cpp
+++ b/src/corelib/io/qtextstream.cpp
@@ -859,6 +859,21 @@ void QTextStreamPrivate::write(QLatin1String data)
     }
 }
 
+/*!
+    \internal
+*/
+void QTextStreamPrivate::writePadding(int len)
+{
+    if (string) {
+        // ### What about seek()??
+        string->resize(string->size() + len, params.padChar);
+    } else {
+        writeBuffer.resize(writeBuffer.size() + len, params.padChar);
+        if (writeBuffer.size() > QTEXTSTREAM_BUFFERSIZE)
+            flushWriteBuffer();
+    }
+}
+
 /*!
     \internal
 */
@@ -916,31 +931,24 @@ QTextStreamPrivate::PaddingResult QTextStreamPrivate::padding(int len) const
 {
     Q_ASSERT(params.fieldWidth > len); // calling padding() when no padding is needed is an error
 
-    // Do NOT break NRVO in this function or kittens will die!
-
-    PaddingResult result;
+    int left = 0, right = 0;
 
     const int padSize = params.fieldWidth - len;
 
-    result.padding.resize(padSize);
-    std::fill_n(result.padding.begin(), padSize, params.padChar);
-
     switch (params.fieldAlignment) {
     case QTextStream::AlignLeft:
-        result.left  = 0;
-        result.right = padSize;
+        right = padSize;
         break;
     case QTextStream::AlignRight:
     case QTextStream::AlignAccountingStyle:
-        result.left  = padSize;
-        result.right = 0;
+        left  = padSize;
         break;
     case QTextStream::AlignCenter:
-        result.left  = padSize/2;
-        result.right = padSize - padSize/2;
+        left  = padSize/2;
+        right = padSize - padSize/2;
         break;
     }
-
+    const PaddingResult result = { left, right };
     return result;
 }
 
@@ -965,9 +973,9 @@ void QTextStreamPrivate::putString(const QChar *data, int len, bool number)
             }
         }
 
-        write(pad.padding.constData(), pad.left);
+        writePadding(pad.left);
         write(data, len);
-        write(pad.padding.constData(), pad.right);
+        writePadding(pad.right);
     } else {
         write(data, len);
     }
@@ -993,9 +1001,9 @@ void QTextStreamPrivate::putString(QLatin1String data, bool number)
             }
         }
 
-        write(pad.padding.constData(), pad.left);
+        writePadding(pad.left);
         write(data);
-        write(pad.padding.constData(), pad.right);
+        writePadding(pad.right);
     } else {
         write(data);
     }
diff --git a/src/corelib/io/qtextstream_p.h b/src/corelib/io/qtextstream_p.h
index 115408a6dd5..6c6cbe1e6ec 100644
--- a/src/corelib/io/qtextstream_p.h
+++ b/src/corelib/io/qtextstream_p.h
@@ -169,6 +169,7 @@ public:
     inline void write(QChar ch);
     void write(const QChar *data, int len);
     void write(QLatin1String data);
+    void writePadding(int len);
     inline void putString(const QString &ch, bool number = false) { putString(ch.constData(), ch.length(), number); }
     void putString(const QChar *data, int len, bool number = false);
     void putString(QLatin1String data, bool number = false);
@@ -176,10 +177,7 @@ public:
     void putNumber(qulonglong number, bool negative);
 
     struct PaddingResult {
-        enum { PreallocatedPadding = 80 }; // typical line length
-
         int left, right;
-        QVarLengthArray<QChar, PreallocatedPadding> padding;
     };
     PaddingResult padding(int len) const;