From 93462d87c3c8f398d5900be84349f29cb088d849 Mon Sep 17 00:00:00 2001
From: mitchell <unknown>
Date: Sat, 5 May 2018 11:52:27 -0400
Subject: Backport: Feature [feature-requests:#1211]. Use pre-computed table
 for UTF8BytesOfLead. Friendlier treatment of invalid UTF-8. Add tests for
 UniConversion handling invalid UTF-8. Simplify UTF8Classify tests.

Backport of changeset 6643:ebbb4e5aaf93.
---
 cocoa/PlatCocoa.mm | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

(limited to 'cocoa')

diff --git a/cocoa/PlatCocoa.mm b/cocoa/PlatCocoa.mm
index ea4149d97..ab9d449a0 100644
--- a/cocoa/PlatCocoa.mm
+++ b/cocoa/PlatCocoa.mm
@@ -31,6 +31,7 @@
 
 #include "StringCopy.h"
 #include "XPM.h"
+#include "UniConversion.h"
 
 #import "ScintillaView.h"
 #import "ScintillaCocoa.h"
@@ -923,18 +924,6 @@ void SurfaceImpl::DrawTextTransparent(PRectangle rc, Font &font_, XYPOSITION yba
 	textLayout->draw(rc.left, ybase);
 }
 
-static size_t utf8LengthFromLead(unsigned char uch) {
-	if (uch >= (0x80 + 0x40 + 0x20 + 0x10)) {
-		return 4;
-	} else if (uch >= (0x80 + 0x40 + 0x20)) {
-		return 3;
-	} else if (uch >= (0x80)) {
-		return 2;
-	} else {
-		return 1;
-	}
-}
-
 //--------------------------------------------------------------------------------------------------
 
 void SurfaceImpl::MeasureWidths(Font &font_, const char *s, int len, XYPOSITION *positions)
@@ -952,10 +941,10 @@ void SurfaceImpl::MeasureWidths(Font &font_, const char *s, int len, XYPOSITION
 		const unsigned char *us = reinterpret_cast<const unsigned char *>(s);
 		int i=0;
 		while (ui<fit) {
-			size_t lenChar = utf8LengthFromLead(us[i]);
-			size_t codeUnits = (lenChar < 4) ? 1 : 2;
+			const unsigned int byteCount = UTF8BytesOfLead[us[i]];
+			const int codeUnits = UTF16LengthFromUTF8ByteCount(byteCount);
 			CGFloat xPosition = CTLineGetOffsetForStringIndex(mLine, ui+codeUnits, NULL);
-			for (unsigned int bytePos=0; (bytePos<lenChar) && (i<len); bytePos++) {
+			for (unsigned int bytePos=0; (bytePos<byteCount) && (i<len); bytePos++) {
 				positions[i++] = static_cast<XYPOSITION>(xPosition);
 			}
 			ui += codeUnits;
-- 
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