From fce09f139ca076f1c59515ca3a44f272788faaf8 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Thu, 18 Oct 2012 20:09:54 +0000
Subject: [PATCH] Emit diagnostics in chunks even when we're trying to print
 colored template diffs.

char-by-char is really slow on an unbuffered stream.

llvm-svn: 166218
---
 clang/lib/Frontend/TextDiagnostic.cpp | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index a8a5613eaace..e47b5687ff49 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -43,19 +43,22 @@ static const enum raw_ostream::Colors savedColor =
 /// \brief Add highlights to differences in template strings.
 static void applyTemplateHighlighting(raw_ostream &OS, StringRef Str,
                                       bool &Normal, bool Bold) {
-  for (unsigned i = 0, e = Str.size(); i < e; ++i)
-    if (Str[i] != ToggleHighlight) {
-      OS << Str[i];
-    } else {
-      if (Normal)
-        OS.changeColor(templateColor, true);
-      else {
-        OS.resetColor();
-        if (Bold)
-          OS.changeColor(savedColor, true);
-      }
-      Normal = !Normal;
+  while (1) {
+    size_t Pos = Str.find(ToggleHighlight);
+    OS << Str.slice(0, Pos);
+    if (Pos == StringRef::npos)
+      break;
+
+    Str = Str.substr(Pos + 1);
+    if (Normal)
+      OS.changeColor(templateColor, true);
+    else {
+      OS.resetColor();
+      if (Bold)
+        OS.changeColor(savedColor, true);
     }
+    Normal = !Normal;
+  }
 }
 
 /// \brief Number of spaces to indent when word-wrapping.