From cdd1be0f8a264264495fce7291a7dfca89fbf019 Mon Sep 17 00:00:00 2001
From: Tzu-ping Chung <uranusjr@gmail.com>
Date: Fri, 3 Oct 2014 10:44:33 +0800
Subject: [PATCH] Fix whitespaces calculation logic for deletion

Fix #176
---
 MacDown/Code/Extension/NSTextView+Autocomplete.m | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/MacDown/Code/Extension/NSTextView+Autocomplete.m b/MacDown/Code/Extension/NSTextView+Autocomplete.m
index a2042b4..4e404aa 100644
--- a/MacDown/Code/Extension/NSTextView+Autocomplete.m
+++ b/MacDown/Code/Extension/NSTextView+Autocomplete.m
@@ -249,11 +249,15 @@ static NSString * const kMPBlockquoteLinePattern = @"^((?:\\> ?)+).*$";
     if (whitespaceCount < 2)
         return NO;
 
-    NSUInteger offset =
-        ([self.string locationOfFirstNewlineBefore:location] + 1) % 4;
+    NSUInteger lineStart = [string locationOfFirstNewlineBefore:location] + 1;
+    if (location <= lineStart)
+        return NO;
+
+    NSUInteger offset = (location - lineStart) % 4;
     if (offset == 0)
         offset = 4;
-    offset = offset > whitespaceCount ? whitespaceCount : 4;
+    if (whitespaceCount < offset)
+        offset = whitespaceCount;
     NSRange range = NSMakeRange(location - offset, offset);
 
     [self replaceCharactersInRange:range withString:@""];