/*
- * $PostgreSQL: pgsql/contrib/pg_trgm/trgm_op.c,v 1.11 2008/11/12 13:43:54 teodor Exp $
+ * contrib/pg_trgm/trgm_op.c
*/
-#include "trgm.h"
+#include "postgres.h"
+
#include <ctype.h>
-#include "utils/array.h"
+
+#include "trgm.h"
+
#include "catalog/pg_type.h"
#include "tsearch/ts_locale.h"
+
PG_MODULE_MAGIC;
float4 trgm_limit = 0.3f;
PG_FUNCTION_INFO_V1(set_limit);
Datum set_limit(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(show_limit);
+Datum show_limit(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(show_trgm);
+Datum show_trgm(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(similarity);
+Datum similarity(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(similarity_dist);
+Datum similarity_dist(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(similarity_op);
+Datum similarity_op(PG_FUNCTION_ARGS);
+
+
Datum
set_limit(PG_FUNCTION_ARGS)
{
PG_RETURN_FLOAT4(trgm_limit);
}
-PG_FUNCTION_INFO_V1(show_limit);
-Datum show_limit(PG_FUNCTION_ARGS);
Datum
show_limit(PG_FUNCTION_ARGS)
{
}
static int
-unique_array(trgm * a, int len)
+unique_array(trgm *a, int len)
{
trgm *curend,
*tmp;
}
#ifdef KEEPONLYALNUM
-#define iswordchr(c) (t_isalpha(c) || t_isdigit(c))
+#define iswordchr(c) (t_isalpha(c) || t_isdigit(c))
#else
#define iswordchr(c) (!t_isspace(c))
#endif
* Finds first word in string, returns pointer to the word,
* endword points to the character after word
*/
-static char*
-find_word(char *str, int lenstr, char **endword, int *charlen)
+static char *
+find_word(char *str, int lenstr, char **endword, int *charlen)
{
- char *beginword = str;
+ char *beginword = str;
- while( beginword - str < lenstr && !iswordchr(beginword) )
+ while (beginword - str < lenstr && !iswordchr(beginword))
beginword += pg_mblen(beginword);
if (beginword - str >= lenstr)
*endword = beginword;
*charlen = 0;
- while( *endword - str < lenstr && iswordchr(*endword) )
+ while (*endword - str < lenstr && iswordchr(*endword))
{
*endword += pg_mblen(*endword);
(*charlen)++;
#ifdef USE_WIDE_UPPER_LOWER
static void
-cnt_trigram(trgm *tptr, char *str, int bytelen)
+cnt_trigram(trgm *tptr, char *str, int bytelen)
{
- if ( bytelen == 3 )
+ if (bytelen == 3)
{
- CPTRGM(tptr, str);
+ CPTRGM(tptr, str);
}
else
{
FIN_CRC32(crc);
/*
- * use only 3 upper bytes from crc, hope, it's
- * good enough hashing
+ * use only 3 upper bytes from crc, hope, it's good enough hashing
*/
CPTRGM(tptr, &crc);
}
#endif
/*
- * Adds trigramm from words (already padded).
+ * Adds trigrams from words (already padded).
*/
-static trgm*
-make_trigrams( trgm *tptr, char *str, int bytelen, int charlen )
+static trgm *
+make_trigrams(trgm *tptr, char *str, int bytelen, int charlen)
{
- char *ptr = str;
+ char *ptr = str;
- if ( charlen < 3 )
+ if (charlen < 3)
return tptr;
#ifdef USE_WIDE_UPPER_LOWER
if (pg_database_encoding_max_length() > 1)
{
- int lenfirst = pg_mblen(str),
- lenmiddle = pg_mblen(str + lenfirst),
- lenlast = pg_mblen(str + lenfirst + lenmiddle);
+ int lenfirst = pg_mblen(str),
+ lenmiddle = pg_mblen(str + lenfirst),
+ lenlast = pg_mblen(str + lenfirst + lenmiddle);
- while( (ptr - str) + lenfirst + lenmiddle + lenlast <= bytelen )
+ while ((ptr - str) + lenfirst + lenmiddle + lenlast <= bytelen)
{
cnt_trigram(tptr, ptr, lenfirst + lenmiddle + lenlast);
ptr += lenfirst;
tptr++;
- lenfirst = lenmiddle;
- lenmiddle = lenlast;
- lenlast = pg_mblen(ptr + lenfirst + lenmiddle);
+ lenfirst = lenmiddle;
+ lenmiddle = lenlast;
+ lenlast = pg_mblen(ptr + lenfirst + lenmiddle);
}
}
else
#endif
{
- Assert( bytelen == charlen );
+ Assert(bytelen == charlen);
while (ptr - str < bytelen - 2 /* number of trigrams = strlen - 2 */ )
{
tptr++;
}
}
-
+
return tptr;
}
int len,
charlen,
bytelen;
- char *bword, *eword;
+ char *bword,
+ *eword;
- trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) * 3);
+ trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) *3);
trg->flag = ARRKEY;
SET_VARSIZE(trg, TRGMHDRSIZE);
}
eword = str;
- while( (bword=find_word(eword, slen - (eword-str), &eword, &charlen)) != NULL )
+ while ((bword = find_word(eword, slen - (eword - str), &eword, &charlen)) != NULL)
{
#ifdef IGNORECASE
bword = lowerstr_with_len(bword, eword - bword);
#ifdef IGNORECASE
pfree(bword);
#endif
- buf[LPADDING+bytelen] = ' ';
- buf[LPADDING+bytelen+1] = ' ';
+ buf[LPADDING + bytelen] = ' ';
+ buf[LPADDING + bytelen + 1] = ' ';
/*
* count trigrams
*/
- tptr = make_trigrams( tptr, buf, bytelen + LPADDING + RPADDING,
- charlen + LPADDING + RPADDING );
+ tptr = make_trigrams(tptr, buf, bytelen + LPADDING + RPADDING,
+ charlen + LPADDING + RPADDING);
}
pfree(buf);
return trg;
}
+/*
+ * Extract the next non-wildcard part of a search string, ie, a word bounded
+ * by '_' or '%' meta-characters, non-word characters or string end.
+ *
+ * str: source string, of length lenstr bytes (need not be null-terminated)
+ * buf: where to return the substring (must be long enough)
+ * *bytelen: receives byte length of the found substring
+ * *charlen: receives character length of the found substring
+ *
+ * Returns pointer to end+1 of the found substring in the source string.
+ * Returns NULL if no word found (in which case buf, bytelen, charlen not set)
+ *
+ * If the found word is bounded by non-word characters or string boundaries
+ * then this function will include corresponding padding spaces into buf.
+ */
+static const char *
+get_wildcard_part(const char *str, int lenstr,
+ char *buf, int *bytelen, int *charlen)
+{
+ const char *beginword = str;
+ const char *endword;
+ char *s = buf;
+ bool in_leading_wildcard_meta = false;
+ bool in_trailing_wildcard_meta = false;
+ bool in_escape = false;
+ int clen;
+
+ /*
+ * Find the first word character, remembering whether preceding character
+ * was wildcard meta-character. Note that the in_escape state persists
+ * from this loop to the next one, since we may exit at a word character
+ * that is in_escape.
+ */
+ while (beginword - str < lenstr)
+ {
+ if (in_escape)
+ {
+ if (iswordchr(beginword))
+ break;
+ in_escape = false;
+ in_leading_wildcard_meta = false;
+ }
+ else
+ {
+ if (ISESCAPECHAR(beginword))
+ in_escape = true;
+ else if (ISWILDCARDCHAR(beginword))
+ in_leading_wildcard_meta = true;
+ else if (iswordchr(beginword))
+ break;
+ else
+ in_leading_wildcard_meta = false;
+ }
+ beginword += pg_mblen(beginword);
+ }
+
+ /*
+ * Handle string end.
+ */
+ if (beginword - str >= lenstr)
+ return NULL;
+
+ /*
+ * Add left padding spaces if preceding character wasn't wildcard
+ * meta-character.
+ */
+ *charlen = 0;
+ if (!in_leading_wildcard_meta)
+ {
+ if (LPADDING > 0)
+ {
+ *s++ = ' ';
+ (*charlen)++;
+ if (LPADDING > 1)
+ {
+ *s++ = ' ';
+ (*charlen)++;
+ }
+ }
+ }
+
+ /*
+ * Copy data into buf until wildcard meta-character, non-word character or
+ * string boundary. Strip escapes during copy.
+ */
+ endword = beginword;
+ while (endword - str < lenstr)
+ {
+ clen = pg_mblen(endword);
+ if (in_escape)
+ {
+ if (iswordchr(endword))
+ {
+ memcpy(s, endword, clen);
+ (*charlen)++;
+ s += clen;
+ }
+ else
+ {
+ /*
+ * Back up endword to the escape character when stopping at
+ * an escaped char, so that subsequent get_wildcard_part will
+ * restart from the escape character. We assume here that
+ * escape chars are single-byte.
+ */
+ endword--;
+ break;
+ }
+ in_escape = false;
+ }
+ else
+ {
+ if (ISESCAPECHAR(endword))
+ in_escape = true;
+ else if (ISWILDCARDCHAR(endword))
+ {
+ in_trailing_wildcard_meta = true;
+ break;
+ }
+ else if (iswordchr(endword))
+ {
+ memcpy(s, endword, clen);
+ (*charlen)++;
+ s += clen;
+ }
+ else
+ break;
+ }
+ endword += clen;
+ }
+
+ /*
+ * Add right padding spaces if next character isn't wildcard
+ * meta-character.
+ */
+ if (!in_trailing_wildcard_meta)
+ {
+ if (RPADDING > 0)
+ {
+ *s++ = ' ';
+ (*charlen)++;
+ if (RPADDING > 1)
+ {
+ *s++ = ' ';
+ (*charlen)++;
+ }
+ }
+ }
+
+ *bytelen = s - buf;
+ return endword;
+}
+
+/*
+ * Generates trigrams for wildcard search string.
+ *
+ * Returns array of trigrams that must occur in any string that matches the
+ * wildcard string. For example, given pattern "a%bcd%" the trigrams
+ * " a", "bcd" would be extracted.
+ */
+TRGM *
+generate_wildcard_trgm(const char *str, int slen)
+{
+ TRGM *trg;
+ char *buf,
+ *buf2;
+ trgm *tptr;
+ int len,
+ charlen,
+ bytelen;
+ const char *eword;
+
+ trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) *3);
+ trg->flag = ARRKEY;
+ SET_VARSIZE(trg, TRGMHDRSIZE);
+
+ if (slen + LPADDING + RPADDING < 3 || slen == 0)
+ return trg;
+
+ tptr = GETARR(trg);
+
+ buf = palloc(sizeof(char) * (slen + 4));
+
+ /*
+ * Extract trigrams from each substring extracted by get_wildcard_part.
+ */
+ eword = str;
+ while ((eword = get_wildcard_part(eword, slen - (eword - str),
+ buf, &bytelen, &charlen)) != NULL)
+ {
+#ifdef IGNORECASE
+ buf2 = lowerstr_with_len(buf, bytelen);
+ bytelen = strlen(buf2);
+#else
+ buf2 = buf;
+#endif
+
+ /*
+ * count trigrams
+ */
+ tptr = make_trigrams(tptr, buf2, bytelen, charlen);
+#ifdef IGNORECASE
+ pfree(buf2);
+#endif
+ }
+
+ pfree(buf);
+
+ if ((len = tptr - GETARR(trg)) == 0)
+ return trg;
+
+ /*
+ * Make trigrams unique.
+ */
+ if (len > 0)
+ {
+ qsort((void *) GETARR(trg), len, sizeof(trgm), comp_trgm);
+ len = unique_array(GETARR(trg), len);
+ }
+
+ SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));
+
+ return trg;
+}
+
uint32
trgm2int(trgm *ptr)
{
- uint32 val = 0;
+ uint32 val = 0;
- val |= *( ((unsigned char*)ptr) );
+ val |= *(((unsigned char *) ptr));
val <<= 8;
- val |= *( ((unsigned char*)ptr) + 1 );
+ val |= *(((unsigned char *) ptr) + 1);
val <<= 8;
- val |= *( ((unsigned char*)ptr) + 2 );
+ val |= *(((unsigned char *) ptr) + 2);
return val;
}
-PG_FUNCTION_INFO_V1(show_trgm);
-Datum show_trgm(PG_FUNCTION_ARGS);
Datum
show_trgm(PG_FUNCTION_ARGS)
{
for (i = 0, ptr = GETARR(trg); i < ARRNELEM(trg); i++, ptr++)
{
- text *item = (text *) palloc(VARHDRSZ + Max(12, pg_database_encoding_max_length()*3) );
+ text *item = (text *) palloc(VARHDRSZ + Max(12, pg_database_encoding_max_length() * 3));
- if ( pg_database_encoding_max_length() > 1 && !ISPRINTABLETRGM(ptr) )
+ if (pg_database_encoding_max_length() > 1 && !ISPRINTABLETRGM(ptr))
{
snprintf(VARDATA(item), 12, "0x%06x", trgm2int(ptr));
SET_VARSIZE(item, VARHDRSZ + strlen(VARDATA(item)));
}
float4
-cnt_sml(TRGM * trg1, TRGM * trg2)
+cnt_sml(TRGM *trg1, TRGM *trg2)
{
trgm *ptr1,
*ptr2;
}
-PG_FUNCTION_INFO_V1(similarity);
-Datum similarity(PG_FUNCTION_ARGS);
+/*
+ * Returns whether trg2 contains all trigrams in trg1.
+ * This relies on the trigram arrays being sorted.
+ */
+bool
+trgm_contained_by(TRGM *trg1, TRGM *trg2)
+{
+ trgm *ptr1,
+ *ptr2;
+ int len1,
+ len2;
+
+ ptr1 = GETARR(trg1);
+ ptr2 = GETARR(trg2);
+
+ len1 = ARRNELEM(trg1);
+ len2 = ARRNELEM(trg2);
+
+ while (ptr1 - GETARR(trg1) < len1 && ptr2 - GETARR(trg2) < len2)
+ {
+ int res = CMPTRGM(ptr1, ptr2);
+
+ if (res < 0)
+ return false;
+ else if (res > 0)
+ ptr2++;
+ else
+ {
+ ptr1++;
+ ptr2++;
+ }
+ }
+ if (ptr1 - GETARR(trg1) < len1)
+ return false;
+ else
+ return true;
+}
+
Datum
similarity(PG_FUNCTION_ARGS)
{
PG_RETURN_FLOAT4(res);
}
-PG_FUNCTION_INFO_V1(similarity_op);
-Datum similarity_op(PG_FUNCTION_ARGS);
+Datum
+similarity_dist(PG_FUNCTION_ARGS)
+{
+ float4 res = DatumGetFloat4(DirectFunctionCall2(similarity,
+ PG_GETARG_DATUM(0),
+ PG_GETARG_DATUM(1)));
+
+ PG_RETURN_FLOAT4(1.0 - res);
+}
+
Datum
similarity_op(PG_FUNCTION_ARGS)
{
- float4 res = DatumGetFloat4(DirectFunctionCall2(
- similarity,
+ float4 res = DatumGetFloat4(DirectFunctionCall2(similarity,
PG_GETARG_DATUM(0),
- PG_GETARG_DATUM(1)
- ));
+ PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(res >= trgm_limit);
}
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