/* These prevent GH from becoming F */
#define NOGHTOF(c) (getcode(c) & 16) /* BDH */
-/* Faster than memcmp(), for this use case. */
-static inline bool
-rest_of_char_same(const char *s1, const char *s2, int len)
-{
- while (len > 0)
- {
- len--;
- if (s1[len] != s2[len])
- return false;
- }
- return true;
-}
-
-#include "levenshtein.c"
-#define LEVENSHTEIN_LESS_EQUAL
-#include "levenshtein.c"
-
PG_FUNCTION_INFO_V1(levenshtein_with_costs);
Datum
levenshtein_with_costs(PG_FUNCTION_ARGS)
int ins_c = PG_GETARG_INT32(2);
int del_c = PG_GETARG_INT32(3);
int sub_c = PG_GETARG_INT32(4);
-
- PG_RETURN_INT32(levenshtein_internal(src, dst, ins_c, del_c, sub_c));
+ const char *s_data;
+ const char *t_data;
+ int s_bytes,
+ t_bytes;
+
+ /* Extract a pointer to the actual character data */
+ s_data = VARDATA_ANY(src);
+ t_data = VARDATA_ANY(dst);
+ /* Determine length of each string in bytes and characters */
+ s_bytes = VARSIZE_ANY_EXHDR(src);
+ t_bytes = VARSIZE_ANY_EXHDR(dst);
+
+ PG_RETURN_INT32(varstr_levenshtein(s_data, s_bytes, t_data, t_bytes, ins_c,
+ del_c, sub_c));
}
{
text *src = PG_GETARG_TEXT_PP(0);
text *dst = PG_GETARG_TEXT_PP(1);
-
- PG_RETURN_INT32(levenshtein_internal(src, dst, 1, 1, 1));
+ const char *s_data;
+ const char *t_data;
+ int s_bytes,
+ t_bytes;
+
+ /* Extract a pointer to the actual character data */
+ s_data = VARDATA_ANY(src);
+ t_data = VARDATA_ANY(dst);
+ /* Determine length of each string in bytes and characters */
+ s_bytes = VARSIZE_ANY_EXHDR(src);
+ t_bytes = VARSIZE_ANY_EXHDR(dst);
+
+ PG_RETURN_INT32(varstr_levenshtein(s_data, s_bytes, t_data, t_bytes, 1, 1,
+ 1));
}
int del_c = PG_GETARG_INT32(3);
int sub_c = PG_GETARG_INT32(4);
int max_d = PG_GETARG_INT32(5);
-
- PG_RETURN_INT32(levenshtein_less_equal_internal(src, dst, ins_c, del_c, sub_c, max_d));
+ const char *s_data;
+ const char *t_data;
+ int s_bytes,
+ t_bytes;
+
+ /* Extract a pointer to the actual character data */
+ s_data = VARDATA_ANY(src);
+ t_data = VARDATA_ANY(dst);
+ /* Determine length of each string in bytes and characters */
+ s_bytes = VARSIZE_ANY_EXHDR(src);
+ t_bytes = VARSIZE_ANY_EXHDR(dst);
+
+ PG_RETURN_INT32(varstr_levenshtein_less_equal(s_data, s_bytes, t_data,
+ t_bytes, ins_c, del_c,
+ sub_c, max_d));
}
text *src = PG_GETARG_TEXT_PP(0);
text *dst = PG_GETARG_TEXT_PP(1);
int max_d = PG_GETARG_INT32(2);
-
- PG_RETURN_INT32(levenshtein_less_equal_internal(src, dst, 1, 1, 1, max_d));
+ const char *s_data;
+ const char *t_data;
+ int s_bytes,
+ t_bytes;
+
+ /* Extract a pointer to the actual character data */
+ s_data = VARDATA_ANY(src);
+ t_data = VARDATA_ANY(dst);
+ /* Determine length of each string in bytes and characters */
+ s_bytes = VARSIZE_ANY_EXHDR(src);
+ t_bytes = VARSIZE_ANY_EXHDR(dst);
+
+ PG_RETURN_INT32(varstr_levenshtein_less_equal(s_data, s_bytes, t_data,
+ t_bytes, 1, 1, 1, max_d));
}
-/*
+/*-------------------------------------------------------------------------
+ *
* levenshtein.c
+ * Levenshtein distance implementation.
*
- * Functions for "fuzzy" comparison of strings
+ * Original author: Joe Conway <mail@joeconway.com>
*
- * Joe Conway <mail@joeconway.com>
+ * This file is included by varlena.c twice, to provide matching code for (1)
+ * Levenshtein distance with custom costings, and (2) Levenshtein distance with
+ * custom costings and a "max" value above which exact distances are not
+ * interesting. Before the inclusion, we rely on the presence of the inline
+ * function rest_of_char_same().
+ *
+ * Written based on a description of the algorithm by Michael Gilleland found
+ * at http://www.merriampark.com/ld.htm. Also looked at levenshtein.c in the
+ * PHP 4.0.6 distribution for inspiration. Configurable penalty costs
+ * extension is introduced by Volkan YAZICI <volkan.yazici@gmail.com.
*
* Copyright (c) 2001-2014, PostgreSQL Global Development Group
- * ALL RIGHTS RESERVED;
*
- * levenshtein()
- * -------------
- * Written based on a description of the algorithm by Michael Gilleland
- * found at http://www.merriampark.com/ld.htm
- * Also looked at levenshtein.c in the PHP 4.0.6 distribution for
- * inspiration.
- * Configurable penalty costs extension is introduced by Volkan
- * YAZICI <volkan.yazici@gmail.com>.
- */
-
-/*
- * External declarations for exported functions
+ * IDENTIFICATION
+ * src/backend/utils/adt/levenshtein.c
+ *
+ *-------------------------------------------------------------------------
*/
-#ifdef LEVENSHTEIN_LESS_EQUAL
-static int levenshtein_less_equal_internal(text *s, text *t,
- int ins_c, int del_c, int sub_c, int max_d);
-#else
-static int levenshtein_internal(text *s, text *t,
- int ins_c, int del_c, int sub_c);
-#endif
-
#define MAX_LEVENSHTEIN_STRLEN 255
-
/*
- * Calculates Levenshtein distance metric between supplied strings. Generally
- * (1, 1, 1) penalty costs suffices for common cases, but your mileage may
- * vary.
+ * Calculates Levenshtein distance metric between supplied csrings, which are
+ * not necessarily null-terminated. Generally (1, 1, 1) penalty costs suffices
+ * for common cases, but your mileage may vary.
*
* One way to compute Levenshtein distance is to incrementally construct
* an (m+1)x(n+1) matrix where cell (i, j) represents the minimum number
* identify the portion of the matrix close to the diagonal which can still
* affect the final answer.
*/
-static int
+int
#ifdef LEVENSHTEIN_LESS_EQUAL
-levenshtein_less_equal_internal(text *s, text *t,
- int ins_c, int del_c, int sub_c, int max_d)
+varstr_levenshtein_less_equal(const char *source, int slen, const char *target,
+ int tlen, int ins_c, int del_c, int sub_c,
+ int max_d)
#else
-levenshtein_internal(text *s, text *t,
- int ins_c, int del_c, int sub_c)
+varstr_levenshtein(const char *source, int slen, const char *target, int tlen,
+ int ins_c, int del_c, int sub_c)
#endif
{
int m,
- n,
- s_bytes,
- t_bytes;
+ n;
int *prev;
int *curr;
int *s_char_len = NULL;
int i,
j;
- const char *s_data;
- const char *t_data;
const char *y;
/*
- * For levenshtein_less_equal_internal, we have real variables called
+ * For varstr_levenshtein_less_equal, we have real variables called
* start_column and stop_column; otherwise it's just short-hand for 0 and
* m.
*/
#define STOP_COLUMN m
#endif
- /* Extract a pointer to the actual character data. */
- s_data = VARDATA_ANY(s);
- t_data = VARDATA_ANY(t);
-
- /* Determine length of each string in bytes and characters. */
- s_bytes = VARSIZE_ANY_EXHDR(s);
- t_bytes = VARSIZE_ANY_EXHDR(t);
- m = pg_mbstrlen_with_len(s_data, s_bytes);
- n = pg_mbstrlen_with_len(t_data, t_bytes);
+ m = pg_mbstrlen_with_len(source, slen);
+ n = pg_mbstrlen_with_len(target, tlen);
/*
* We can transform an empty s into t with n insertions, or a non-empty t
* multi-byte characters, we still build the array, so that the fast-path
* needn't deal with the case where the array hasn't been initialized.
*/
- if (m != s_bytes || n != t_bytes)
+ if (m != slen || n != tlen)
{
int i;
- const char *cp = s_data;
+ const char *cp = source;
s_char_len = (int *) palloc((m + 1) * sizeof(int));
for (i = 0; i < m; ++i)
prev[i] = i * del_c;
/* Loop through rows of the notional array */
- for (y = t_data, j = 1; j < n; j++)
+ for (y = target, j = 1; j < n; j++)
{
int *temp;
- const char *x = s_data;
- int y_char_len = n != t_bytes + 1 ? pg_mblen(y) : 1;
+ const char *x = source;
+ int y_char_len = n != tlen + 1 ? pg_mblen(y) : 1;
#ifdef LEVENSHTEIN_LESS_EQUAL
prev[start_column] = max_d + 1;
curr[start_column] = max_d + 1;
if (start_column != 0)
- s_data += (s_char_len != NULL) ? s_char_len[start_column - 1] : 1;
+ source += (s_char_len != NULL) ? s_char_len[start_column - 1] : 1;
start_column++;
}
projects / postgresql / commitdiff