diff options
Diffstat (limited to 'src/backend/utils/adt/numeric.c')
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 3e5614ece30..22d5898927c 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -2230,6 +2230,66 @@ hash_numeric(PG_FUNCTION_ARGS) PG_RETURN_DATUM(result); } +/* + * Returns 64-bit value by hashing a value to a 64-bit value, with a seed. + * Otherwise, similar to hash_numeric. + */ +Datum +hash_numeric_extended(PG_FUNCTION_ARGS) +{ + Numeric key = PG_GETARG_NUMERIC(0); + uint64 seed = PG_GETARG_INT64(1); + Datum digit_hash; + Datum result; + int weight; + int start_offset; + int end_offset; + int i; + int hash_len; + NumericDigit *digits; + + if (NUMERIC_IS_NAN(key)) + PG_RETURN_UINT64(seed); + + weight = NUMERIC_WEIGHT(key); + start_offset = 0; + end_offset = 0; + + digits = NUMERIC_DIGITS(key); + for (i = 0; i < NUMERIC_NDIGITS(key); i++) + { + if (digits[i] != (NumericDigit) 0) + break; + + start_offset++; + + weight--; + } + + if (NUMERIC_NDIGITS(key) == start_offset) + PG_RETURN_UINT64(seed - 1); + + for (i = NUMERIC_NDIGITS(key) - 1; i >= 0; i--) + { + if (digits[i] != (NumericDigit) 0) + break; + + end_offset++; + } + + Assert(start_offset + end_offset < NUMERIC_NDIGITS(key)); + + hash_len = NUMERIC_NDIGITS(key) - start_offset - end_offset; + digit_hash = hash_any_extended((unsigned char *) (NUMERIC_DIGITS(key) + + start_offset), + hash_len * sizeof(NumericDigit), + seed); + + result = digit_hash ^ weight; + + PG_RETURN_DATUM(result); +} + /* ---------------------------------------------------------------------- * |