1 files changed, 90 insertions, 0 deletions
diff --git a/src/dlm.c b/src/dlm.c
new file mode 100755
index 0000000..19c14e3
--- /dev/null
+++ b/src/dlm.c
@@ -0,0 +1,90 @@
+/* dlm.c - 2004/07/04 - Santtu Lakkala */
+
+#include <glib.h>
+#include <string.h>
+
+int dlm_cost    (const gchar, const gchar);
+int dlm_minimum (int a, int b, int c, int d);
+
+/*
+ * Compute the Damerau-Levenshtein Distance between utf-8 strings ds and dt.
+ */
+int dlm (const gchar *ds, const gchar *dt)
+{
+    int i, j, n, m, metric;
+    int *d;
+
+    /* Casefold for better matching of the strings. */
+    gchar *s = g_utf8_casefold(ds, -1);
+    gchar *t = g_utf8_casefold(dt, -1);
+
+    n = strlen(s);
+    m = strlen(t);
+
+    if (n && m)
+    {
+        n++;
+        m++;
+
+        d = (int *)g_malloc0(sizeof(int) * m * n);
+
+        for (i = 0; i < m; i++)
+            d[i * n] = i;
+
+        for (i = 1; i < n; i++)
+        {
+            d[i] = i;
+            for (j = 1; j < m; j++)
+            {
+                d[j * n + i] = dlm_minimum(
+                    d[(j - 1) * n + i] + 1,
+                    d[j * n + i - 1] + 1,
+                    d[(j - 1) * n + i - 1] + dlm_cost(s[i - 1], t[j - 1]),
+                    (j>1 && i>1 ?
+                         d[(j - 2) * n + i - 2] + dlm_cost(s[i - 1], t[j])
+                        + dlm_cost(s[i], t[j - 1])
+                    : 0x7fff)
+                );
+            }
+        }
+        metric = d[n * m - 1];
+        g_free(d);
+
+        /* Count a "similarity value" */
+        metric = 1000 - (1000 * (metric * 2)) / (m + n);
+
+        g_free(t);
+        g_free(s);
+        return metric;
+    }
+    g_free(t);
+    g_free(s);
+
+    /* Return value of -1 indicates an error */
+    return -1;
+}
+
+/* "Cost" of changing from a to b. */
+int dlm_cost (const char a, const char b)
+{
+    return a == b ? 0 : 1;
+}
+
+/* Return the smallest of four integers. */
+int dlm_minimum (int a, int b, int c, int d)
+{
+    int min = a;
+    if (b < min)
+    {
+        min = b;
+    }
+    if (c < min)
+    {
+        min = c;
+    }
+    if (d < min)
+    {
+        min = d;
+    }
+    return min;
+}