From 8cefe7a5183c83040782b5d3611d2f0ca4037b29 Mon Sep 17 00:00:00 2001
From: Neil Hodgson <nyamatongwe@gmail.com>
Date: Thu, 4 Oct 2018 16:23:36 +1000
Subject: Fix crash when particular patterns of invalid UTF-8 led to failure to
 create a CFStringRef. Performs more stringent validation on input text.

---
 cocoa/PlatCocoa.mm        | 5 ++++-
 doc/ScintillaHistory.html | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/cocoa/PlatCocoa.mm b/cocoa/PlatCocoa.mm
index 4789f7528..a74c805a4 100644
--- a/cocoa/PlatCocoa.mm
+++ b/cocoa/PlatCocoa.mm
@@ -164,13 +164,15 @@ public:
 
 ScreenLineLayout::ScreenLineLayout(const IScreenLine *screenLine) : text(screenLine->Text()) {
 	const UInt8 *puiBuffer = reinterpret_cast<const UInt8 *>(text.data());
+	std::string_view sv = text;
 
 	// Start with an empty mutable attributed string and add each character to it.
 	CFMutableAttributedStringRef mas = CFAttributedStringCreateMutable(NULL, 0);
 
 	for (size_t bp=0; bp<text.length();) {
 		const unsigned char uch = text[bp];
-		const unsigned int byteCount = UTF8BytesOfLead[uch];
+		const int utf8Status = UTF8Classify(sv);
+		const unsigned int byteCount = utf8Status & UTF8MaskWidth;
 		XYPOSITION repWidth = screenLine->RepresentationWidth(bp);
 		if (uch == '\t') {
 			// Find the size up to the tab
@@ -207,6 +209,7 @@ ScreenLineLayout::ScreenLineLayout(const IScreenLine *screenLine) : text(screenL
 							  CFRangeMake(CFAttributedStringGetLength(mas), 0),
 							  as);
 		bp += byteCount;
+		sv.remove_prefix(byteCount);
 		CFRelease(as);
 	}
 
diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 236dbb107..5d4e6344d 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -547,6 +547,15 @@
         Icons</a> Copyright(C) 1998 by Dean S. Jones<br />
       </li>
     </ul>
+    <h3>
+       <a href="https://www.scintilla.org/scite413.zip">Release 4.1.3</a>
+    </h3>
+    <ul>
+	<li>
+	Fixed a crash on Cocoa in bidirectional mode where some patterns of invalid UTF-8
+	caused failures to create Unicode strings.
+	</li>
+    </ul>
     <h3>
        <a href="https://www.scintilla.org/scite412.zip">Release 4.1.2</a>
     </h3>
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