From b1fb4f3aa1ec29781d2e25b1a05fb70e143fd24d Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Sun, 29 Jan 2023 15:17:50 +0100
Subject: Diff bugfix

---
 diff.cpp            | 10 ++++++++++
 tests/test-diff.cpp | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/diff.cpp b/diff.cpp
index b56fd51..ea9b04e 100644
--- a/diff.cpp
+++ b/diff.cpp
@@ -81,6 +81,16 @@ void Diff::create(const std::string& old_version, const std::string& new_version
   return;
  }
 
+ // re-adjust if search crossed
+ if (old_pos0 > old_pos1) {
+  old_pos0 = old_pos1;
+  new_pos0 = old_pos1;
+ }
+ if (new_pos0 > new_pos1) {
+  old_pos0 = new_pos1;
+  new_pos0 = new_pos1;
+ }
+
  // insert in the middle
  if (old_pos0 == old_pos1) {
   m_pos0 = old_pos0;
diff --git a/tests/test-diff.cpp b/tests/test-diff.cpp
index 1704cfd..1625716 100644
--- a/tests/test-diff.cpp
+++ b/tests/test-diff.cpp
@@ -6,11 +6,14 @@
 
 #include <stdlib.h>
 
+#include <boost/property_tree/ptree.hpp>
+
 #include "libreichwein/file.h"
 
 #include "diff.h"
 
 namespace fs = std::filesystem;
+namespace pt = boost::property_tree;
 using namespace Reichwein;
 
 class DiffTest: public ::testing::Test
@@ -58,6 +61,18 @@ TEST_F(DiffTest, constructor)
   Diff d{"<diff><start>5</start><end>50</end><data>abc</data></diff>"};
   EXPECT_EQ(d.get_xml(), "<diff><start>5</start><end>50</end><data>abc</data></diff>");
  }
+ 
+ // constructor via ptree
+ {
+  pt::ptree ptree;
+  EXPECT_THROW(Diff d{ptree}, std::exception);
+  
+  ptree.put("diff.start", 0);
+  ptree.put("diff.end", 0);
+  ptree.put("diff.data", "abc");
+  Diff d{ptree};
+  EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>0</end><data>abc</data></diff>");
+ }
 
  // constructor via versions
  {
@@ -120,6 +135,18 @@ TEST_F(DiffTest, constructor)
   Diff d{"abc", "c"};
   EXPECT_EQ(d.get_xml(), "<diff><start>0</start><end>2</end><data/></diff>");
  }
+ {
+  Diff d{"aaaa", "aa"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>2</start><end>4</end><data/></diff>");
+ }
+ {
+  Diff d{"baaaa", "baa"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>3</start><end>5</end><data/></diff>");
+ }
+ {
+  Diff d{"baaaab", "baab"};
+  EXPECT_EQ(d.get_xml(), "<diff><start>1</start><end>3</end><data/></diff>");
+ }
 }
 
 TEST_F(DiffTest, diff_create)
-- 
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