int ldistance( char* requested, char* found)
{
int i,j;
int r_len, f_len;
#if SAFETY > 0
if( strlen(requested)>COMP_LEN || strlen(found)>COMP_LEN )
cout << "*** The length is longer than expected! ***" << endl;
#endif
r_len = (strlen(requested)>COMP_LEN ? COMP_LEN : strlen(requested));
f_len = (strlen(found)>COMP_LEN ? COMP_LEN : strlen(found));
distnce[0][0] = 0;
for (j = 1; j <= ARR_SIZE; j++)
distnce[0][j] = distnce[0][j-1] + addition;
for (j = 1; j <= ARR_SIZE; j++)
distnce[j][0] = distnce[j-1][0] + deletion;
for (i = 1; i <= r_len; i++)
for (j = 1; j <= f_len; j++)
distnce[i][j] = SMALLEST_OF(
(distnce[i-1][j-1] + ZERO_IF_EQUAL(i,j)),
(distnce[i][j-1] + addition),
(distnce[i-1][j] + deletion) );
return( distnce[r_len][f_len] );
}
/******************************
* Compute Levenshtein distance
*****************************/
str
levenshtein_impl(int *result, str *S, str *T, int *insdel_cost, int *replace_cost, int *transpose_cost)
{
char *s = *S;
char *t = *T;
int *d; /* pointer to matrix */
int n; /* length of s */
int m; /* length of t */
int i; /* iterates through s */
int j; /* iterates through t */
char s_i; /* ith character of s */
char t_j; /* jth character of t */
int cost; /* cost */
int cell; /* contents of target cell */
int above; /* contents of cell immediately above */
int left; /* contents of cell immediately to left */
int diag; /* contents of cell immediately above and to left */
int sz; /* number of cells in matrix */
int diag2 = 0, cost2 = 0;
/* Step 1 */
n = (int) strlen(s); /* 64bit: assume strings are less than 2 GB */
m = (int) strlen(t);
if (n == 0) {
*result = m;
return MAL_SUCCEED;
}
if (m == 0) {
*result = n;
return MAL_SUCCEED;
}
sz = (n + 1) * (m + 1) * sizeof(int);
d = (int *) GDKmalloc(sz);
if ( d == NULL)
throw(MAL,"levenshtein", MAL_MALLOC_FAIL);
/* Step 2 */
for (i = 0; i <= n; i++) {
levenshtein_PutAt(d, i, 0, n, i);
}
for (j = 0; j <= m; j++) {
levenshtein_PutAt(d, 0, j, n, j);
}
/* Step 3 */
for (i = 1; i <= n; i++) {
s_i = s[i - 1];
/* Step 4 */
for (j = 1; j <= m; j++) {
t_j = t[j - 1];
/* Step 5 */
if (s_i == t_j) {
cost = 0;
} else {
cost = *replace_cost;
}
/* Step 6 */
above = levenshtein_GetAt(d, i - 1, j, n);
left = levenshtein_GetAt(d, i, j - 1, n);
diag = levenshtein_GetAt(d, i - 1, j - 1, n);
if (j >= 2 && i >= 2) {
/* NEW: detect transpositions */
diag2 = levenshtein_GetAt(d, i - 2, j - 2, n);
if (s[i - 2] == t[j - 1] && s[i - 1] == t[j - 2]) {
cost2 = *transpose_cost;
} else {
cost2 = 2;
}
cell = SMALLEST_OF4(above + *insdel_cost, left + *insdel_cost, diag + cost, diag2 + cost2);
} else {
cell = SMALLEST_OF(above + *insdel_cost, left + *insdel_cost, diag + cost);
}
levenshtein_PutAt(d, i, j, n, cell);
}
}
/* Step 7 */
*result = levenshtein_GetAt(d, n, m, n);
GDKfree(d);
return MAL_SUCCEED;
}
