Move damerauLevenshteinDistance from qt-config's Util to CRSM's own Util

1 files changed, 50 insertions, 0 deletions

diff --git a/src/CRSMUtil.cpp b/src/CRSMUtil.cpp
new file mode 100644
index 0000000..91fa057
--- /dev/null
+++ b/src/CRSMUtil.cpp
@@ -0,0 +1,50 @@
+#include "CRSMUtil.hpp"
+
+namespace Util {
+    int damerauLevenshteinDistance(const QString& s1, const QString& s2)
+    {
+        int length1 = s1.length();
+        int length2 = s2.length();
+        int d[length1+1][length2+1];
+
+        int i;
+        int j;
+        int cost;
+
+        for(i = 0; i <= length1; i++)
+        {
+            d[i][0] = i;
+        }
+        for(j = 0; j <= length2; j++)
+        {
+            d[0][j] = j;
+        }
+        for (i = 0; i < length1;i++)
+        {
+            for(j = 0; j < length2; j++)
+            {
+                if(s1[i] == s2[j])
+                {
+                    cost = 0;
+                }
+                else
+                {
+                    cost = 1;
+                }
+                d[i+1][j+1] = std::min({
+                    d[i][j+1] + 1, // delete
+                    d[i+1][j] + 1, // insert
+                    d[i][j] + cost // substitution
+                });
+                if((i > 0) && (j > 0) && (s1[i] == s2[j-1]) && (s1[i-1] == s2[j]))
+                {
+                    d[i+1][j+1] = std::min(
+                        d[i+1][j+1],
+                        d[i-1][j-1] + cost   // transposition
+                    );
+                }
+            }
+        }
+        return d[length1][length2];
+    }
+}