diff options
Diffstat (limited to 'src/backend/utils/adt/numeric.c')
| -rw-r--r-- | src/backend/utils/adt/numeric.c | 149 |
1 files changed, 141 insertions, 8 deletions
diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c index 28390ee5c35..4214d7af007 100644 --- a/src/backend/utils/adt/numeric.c +++ b/src/backend/utils/adt/numeric.c @@ -14,7 +14,7 @@ * Copyright (c) 1998-2003, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.73 2004/05/07 00:24:58 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.74 2004/05/14 21:42:28 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -252,6 +252,7 @@ static Numeric make_result(NumericVar *var); static void apply_typmod(NumericVar *var, int32 typmod); +static int32 numericvar_to_int4(NumericVar *var); static bool numericvar_to_int8(NumericVar *var, int64 *result); static void int8_to_numericvar(int64 val, NumericVar *var); static double numeric_to_double_no_overflow(Numeric num); @@ -285,6 +286,8 @@ static void sub_abs(NumericVar *var1, NumericVar *var2, NumericVar *result); static void round_var(NumericVar *var, int rscale); static void trunc_var(NumericVar *var, int rscale); static void strip_var(NumericVar *var); +static void compute_bucket(Numeric operand, Numeric bound1, Numeric bound2, + NumericVar *count_var, NumericVar *result_var); /* ---------------------------------------------------------------------- @@ -803,6 +806,125 @@ numeric_floor(PG_FUNCTION_ARGS) PG_RETURN_NUMERIC(res); } +/* + * width_bucket_numeric() - + * + * 'bound1' and 'bound2' are the lower and upper bounds of the + * histogram's range, respectively. 'count' is the number of buckets + * in the histogram. width_bucket() returns an integer indicating the + * bucket number that 'operand' belongs in for an equiwidth histogram + * with the specified characteristics. An operand smaller than the + * lower bound is assigned to bucket 0. An operand greater than the + * upper bound is assigned to an additional bucket (with number + * count+1). + */ +Datum +width_bucket_numeric(PG_FUNCTION_ARGS) +{ + Numeric operand = PG_GETARG_NUMERIC(0); + Numeric bound1 = PG_GETARG_NUMERIC(1); + Numeric bound2 = PG_GETARG_NUMERIC(2); + int32 count = PG_GETARG_INT32(3); + NumericVar count_var; + NumericVar result_var; + int32 result; + + if (count <= 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_ARGUMENT_FOR_WIDTH_BUCKET_FUNCTION), + errmsg("count must be greater than zero"))); + + init_var(&result_var); + init_var(&count_var); + + /* Convert 'count' to a numeric, for ease of use later */ + int8_to_numericvar((int64) count, &count_var); + + switch (cmp_numerics(bound1, bound2)) + { + case 0: + ereport(ERROR, + (errcode(ERRCODE_INVALID_ARGUMENT_FOR_WIDTH_BUCKET_FUNCTION), + errmsg("lower bound cannot equal upper bound"))); + + /* bound1 < bound2 */ + case -1: + if (cmp_numerics(operand, bound1) < 0) + set_var_from_var(&const_zero, &result_var); + else if (cmp_numerics(operand, bound2) >= 0) + add_var(&count_var, &const_one, &result_var); + else + compute_bucket(operand, bound1, bound2, + &count_var, &result_var); + break; + + /* bound1 > bound2 */ + case 1: + if (cmp_numerics(operand, bound1) > 0) + set_var_from_var(&const_zero, &result_var); + else if (cmp_numerics(operand, bound2) <= 0) + add_var(&count_var, &const_one, &result_var); + else + compute_bucket(operand, bound1, bound2, + &count_var, &result_var); + break; + } + + result = numericvar_to_int4(&result_var); + + free_var(&count_var); + free_var(&result_var); + + PG_RETURN_INT32(result); +} + +/* + * compute_bucket() - + * + * If 'operand' is not outside the bucket range, determine the correct + * bucket for it to go. The calculations performed by this function + * are derived directly from the SQL2003 spec. + */ +static void +compute_bucket(Numeric operand, Numeric bound1, Numeric bound2, + NumericVar *count_var, NumericVar *result_var) +{ + NumericVar bound1_var; + NumericVar bound2_var; + NumericVar operand_var; + + init_var(&bound1_var); + init_var(&bound2_var); + init_var(&operand_var); + + set_var_from_num(bound1, &bound1_var); + set_var_from_num(bound2, &bound2_var); + set_var_from_num(operand, &operand_var); + + if (cmp_var(&bound1_var, &bound2_var) < 0) + { + sub_var(&operand_var, &bound1_var, &operand_var); + sub_var(&bound2_var, &bound1_var, &bound2_var); + div_var(&operand_var, &bound2_var, result_var, + select_div_scale(&operand_var, &bound2_var)); + } + else + { + sub_var(&bound1_var, &operand_var, &operand_var); + sub_var(&bound1_var, &bound2_var, &bound1_var); + div_var(&operand_var, &bound1_var, result_var, + select_div_scale(&operand_var, &bound1_var)); + } + + mul_var(result_var, count_var, result_var, + result_var->dscale + count_var->dscale); + add_var(result_var, &const_one, result_var); + floor_var(result_var, result_var); + + free_var(&bound1_var); + free_var(&bound2_var); + free_var(&operand_var); +} /* ---------------------------------------------------------------------- * @@ -1612,7 +1734,6 @@ numeric_int4(PG_FUNCTION_ARGS) { Numeric num = PG_GETARG_NUMERIC(0); NumericVar x; - int64 val; int32 result; /* XXX would it be better to return NULL? */ @@ -1621,17 +1742,30 @@ numeric_int4(PG_FUNCTION_ARGS) (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot convert NaN to integer"))); - /* Convert to variable format and thence to int8 */ + /* Convert to variable format, then convert to int4 */ init_var(&x); set_var_from_num(num, &x); + result = numericvar_to_int4(&x); + free_var(&x); + PG_RETURN_INT32(result); +} - if (!numericvar_to_int8(&x, &val)) +/* + * Given a NumericVar, convert it to an int32. If the NumericVar + * exceeds the range of an int32, raise the appropriate error via + * ereport(). The input NumericVar is *not* free'd. + */ +static int32 +numericvar_to_int4(NumericVar *var) +{ + int32 result; + int64 val; + + if (!numericvar_to_int8(var, &val)) ereport(ERROR, (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE), errmsg("integer out of range"))); - free_var(&x); - /* Down-convert to int4 */ result = (int32) val; @@ -1641,10 +1775,9 @@ numeric_int4(PG_FUNCTION_ARGS) (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE), errmsg("integer out of range"))); - PG_RETURN_INT32(result); + return result; } - Datum int8_numeric(PG_FUNCTION_ARGS) { |