git wrapper: DWIM mistyped commands

[git-core/git.git] / levenshtein.c

diff --git a/levenshtein.c b/levenshtein.c
new file mode 100644 (file)
index 0000000..db52f2c
--- /dev/null
+++ b/levenshtein.c
@@ -0,0 +1,47 @@
+#include "cache.h"
+#include "levenshtein.h"
+
+int levenshtein(const char *string1, const char *string2,
+               int w, int s, int a, int d)
+{
+       int len1 = strlen(string1), len2 = strlen(string2);
+       int *row0 = xmalloc(sizeof(int) * (len2 + 1));
+       int *row1 = xmalloc(sizeof(int) * (len2 + 1));
+       int *row2 = xmalloc(sizeof(int) * (len2 + 1));
+       int i, j;
+
+       for (j = 0; j <= len2; j++)
+               row1[j] = j * a;
+       for (i = 0; i < len1; i++) {
+               int *dummy;
+
+               row2[0] = (i + 1) * d;
+               for (j = 0; j < len2; j++) {
+                       /* substitution */
+                       row2[j + 1] = row1[j] + s * (string1[i] != string2[j]);
+                       /* swap */
+                       if (i > 0 && j > 0 && string1[i - 1] == string2[j] &&
+                                       string1[i] == string2[j - 1] &&
+                                       row2[j + 1] > row0[j - 1] + w)
+                               row2[j + 1] = row0[j - 1] + w;
+                       /* deletion */
+                       if (j + 1 < len2 && row2[j + 1] > row1[j + 1] + d)
+                               row2[j + 1] = row1[j + 1] + d;
+                       /* insertion */
+                       if (row2[j + 1] > row2[j] + a)
+                               row2[j + 1] = row2[j] + a;
+               }
+
+               dummy = row0;
+               row0 = row1;
+               row1 = row2;
+               row2 = dummy;
+       }
+
+       i = row1[len2];
+       free(row0);
+       free(row1);
+       free(row2);
+
+       return i;
+}