From 83e4a7260dd4131b0028ab3d8fa1bd51bc0e55f7 Mon Sep 17 00:00:00 2001
From: Leandro Melo <leandro.melo@nokia.com>
Date: Tue, 31 May 2011 11:57:00 +0200
Subject: [PATCH] C++ editor: Remove unnecessary line split in find usages

Avoid extra allocations since we only the actual line for the case.

Change-Id: I0d0f0db394d9075bbdce24d1d5b5efa55c52f9b3
Reviewed-on: http://codereview.qt.nokia.com/261
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@nokia.com>
---
 src/libs/cplusplus/FindUsages.cpp | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/libs/cplusplus/FindUsages.cpp b/src/libs/cplusplus/FindUsages.cpp
index 7c4f75d558..95aa41221a 100644
--- a/src/libs/cplusplus/FindUsages.cpp
+++ b/src/libs/cplusplus/FindUsages.cpp
@@ -44,6 +44,33 @@
 
 using namespace CPlusPlus;
 
+namespace {
+
+QString fetchLine(const QByteArray &bytes, const int line)
+{
+    int current = 0;
+    const char *s = bytes.constData();
+    while (*s) {
+        if (*s == '\n') {
+            ++current;
+            if (current == line)
+                break;
+        }
+        ++s;
+    }
+
+    if (current == line) {
+        ++s;
+        const char *e = s;
+        while (*e && *e != '\n')
+            ++e;
+        return QString::fromUtf8(s, e - s);
+    }
+    return QString();
+}
+
+} // Anonymous
+
 FindUsages::FindUsages(const QByteArray &originalSource, Document::Ptr doc, const Snapshot &snapshot)
     : ASTVisitor(doc->translationUnit()),
       _id(0),
@@ -167,9 +194,9 @@ void FindUsages::reportResult(unsigned tokenIndex)
     unsigned line, col;
     getTokenStartPosition(tokenIndex, &line, &col);
     QString lineText;
-    QList<QByteArray> lines = _originalSource.split('\n');
-    if (((int) line - 1) < lines.size())
-        lineText = QString::fromUtf8(lines.at(line - 1));
+    const int lines = _originalSource.count('\n') + 1;
+    if (((int) line - 1) < lines)
+        lineText = fetchLine(_originalSource, line - 1);
     else
         lineText = matchingLine(tk);
 
-- 
2.11.0