diff options
Diffstat (limited to 'src/backend/access/hash/hashfunc.c')
| -rw-r--r-- | src/backend/access/hash/hashfunc.c | 44 |
1 files changed, 38 insertions, 6 deletions
diff --git a/src/backend/access/hash/hashfunc.c b/src/backend/access/hash/hashfunc.c index e6595de072..a82b8b32d5 100644 --- a/src/backend/access/hash/hashfunc.c +++ b/src/backend/access/hash/hashfunc.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/access/hash/hashfunc.c,v 1.35 2002/09/04 20:31:09 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/access/hash/hashfunc.c,v 1.36 2003/06/22 22:04:54 tgl Exp $ * * NOTES * These functions are stored in pg_amproc. For each operator class @@ -22,6 +22,7 @@ #include "access/hash.h" +/* Note: this is used for both "char" and boolean datatypes */ Datum hashchar(PG_FUNCTION_ARGS) { @@ -58,6 +59,14 @@ hashfloat4(PG_FUNCTION_ARGS) { float4 key = PG_GETARG_FLOAT4(0); + /* + * On IEEE-float machines, minus zero and zero have different bit patterns + * but should compare as equal. We must ensure that they have the same + * hash value, which is most easily done this way: + */ + if (key == (float4) 0) + PG_RETURN_UINT32(0); + return hash_any((unsigned char *) &key, sizeof(key)); } @@ -66,6 +75,14 @@ hashfloat8(PG_FUNCTION_ARGS) { float8 key = PG_GETARG_FLOAT8(0); + /* + * On IEEE-float machines, minus zero and zero have different bit patterns + * but should compare as equal. We must ensure that they have the same + * hash value, which is most easily done this way: + */ + if (key == (float8) 0) + PG_RETURN_UINT32(0); + return hash_any((unsigned char *) &key, sizeof(key)); } @@ -77,11 +94,6 @@ hashoidvector(PG_FUNCTION_ARGS) return hash_any((unsigned char *) key, INDEX_MAX_KEYS * sizeof(Oid)); } -/* - * Note: hashint2vector currently can't be used as a user hash table - * hash function, because it has no pg_proc entry. We only need it - * for catcache indexing. - */ Datum hashint2vector(PG_FUNCTION_ARGS) { @@ -102,6 +114,26 @@ hashname(PG_FUNCTION_ARGS) return hash_any((unsigned char *) key, keylen); } +Datum +hashtext(PG_FUNCTION_ARGS) +{ + text *key = PG_GETARG_TEXT_P(0); + Datum result; + + /* + * Note: this is currently identical in behavior to hashvarlena, + * but it seems likely that we may need to do something different + * in non-C locales. (See also hashbpchar, if so.) + */ + result = hash_any((unsigned char *) VARDATA(key), + VARSIZE(key) - VARHDRSZ); + + /* Avoid leaking memory for toasted inputs */ + PG_FREE_IF_COPY(key, 0); + + return result; +} + /* * hashvarlena() can be used for any varlena datatype in which there are * no non-significant bits, ie, distinct bitpatterns never compare as equal. |