Get rid of USE_WIDE_UPPER_LOWER dependency in bigram construction.

This is due to the commit in pg_trgm on Apr 7, 2013 by Tom Lane
7844608e54a3a2e3dee461b00fd6ef028a845d7c.

Beena Emerson

diff --git a/bigm_op.c b/bigm_op.c
index aeedc3d..4b4207a 100644 (file)
--- a/bigm_op.c
+++ b/bigm_op.c
@@ -154,13 +154,16 @@ find_word(char *str, int lenstr, char **endword, int *charlen)
        return beginword;
 }
 
-#ifdef USE_WIDE_UPPER_LOWER
+/* 
+ * The function is named compact_bigram to maintain consistency with pg_trgm,
+ * though it does not reduce multibyte characters to hash values like in
+ * compact_trigram.
+ */
 static void
-cnt_bigram(bigm *bptr, char *str, int bytelen)
+compact_bigram(bigm *bptr, char *str, int bytelen)
 {
        CPBIGM(bptr, str, bytelen);
 }
-#endif
 
 /*
  * Adds bigrams from words (already padded).
@@ -172,25 +175,21 @@ make_bigrams(bigm *bptr, char *str, int bytelen, int charlen)
 
        if (charlen < 2)
        {
-#ifdef USE_WIDE_UPPER_LOWER
-               cnt_bigram(bptr, ptr, pg_mblen(str));
-#else
-               CPBIGM(bptr, ptr, 1);
-#endif
+               compact_bigram(bptr, ptr, pg_mblen(str));
                bptr->pmatch = true;
                bptr++;
                return bptr;
        }
 
-#ifdef USE_WIDE_UPPER_LOWER
-       if (pg_database_encoding_max_length() > 1)
+       if (bytelen > charlen)
        {
+               /* Find multibyte character boundaries and call compact_bigram */
                int                     lenfirst = pg_mblen(str),
                                        lenlast = pg_mblen(str + lenfirst);
 
                while ((ptr - str) + lenfirst + lenlast <= bytelen)
                {
-                       cnt_bigram(bptr, ptr, lenfirst + lenlast);
+                       compact_bigram(bptr, ptr, lenfirst + lenlast);
 
                        ptr += lenfirst;
                        bptr++;
@@ -200,8 +199,8 @@ make_bigrams(bigm *bptr, char *str, int bytelen, int charlen)
                }
        }
        else
-#endif
        {
+               /* Fast path when there are no multibyte characters */
                Assert(bytelen == charlen);
 
                while (ptr - str < bytelen - 1 /* number of bigrams = strlen - 1 */ )