aggregates.c

#include <postgres.h>
#include <fmgr.h>

#include "uint.h"

#include <utils/array.h>


#define make_sum_func(argtype, ARGTYPE, RETTYPE) \
PG_FUNCTION_INFO_V1(argtype##_sum); \
Datum \
argtype##_sum(PG_FUNCTION_ARGS) \
{ \
	if (PG_ARGISNULL(0) && PG_ARGISNULL(1)) \
		PG_RETURN_NULL(); \
\
	PG_RETURN_##RETTYPE((PG_ARGISNULL(0) ? 0 : PG_GETARG_##RETTYPE(0)) + \
						(PG_ARGISNULL(1) ? 0 : PG_GETARG_##ARGTYPE(1))); \
} \
extern int no_such_variable

make_sum_func(int1, INT8, INT32);
make_sum_func(uint1, UINT8, UINT32);
make_sum_func(uint2, UINT16, UINT64);
make_sum_func(uint4, UINT32, UINT64);
make_sum_func(uint8, UINT64, UINT64);  // FIXME: should use numeric


typedef struct Int8TransTypeData
{
	int64		count;
	int64		sum;
} Int8TransTypeData;

#define make_avg_func(argtype, ARGTYPE) \
PG_FUNCTION_INFO_V1(argtype##_avg_accum); \
Datum \
argtype##_avg_accum(PG_FUNCTION_ARGS) \
{ \
	ArrayType  *transarray; \
	Int8TransTypeData *transdata; \
\
	transarray = (AggCheckCallContext(fcinfo, NULL)) \
		? PG_GETARG_ARRAYTYPE_P(0) \
		: PG_GETARG_ARRAYTYPE_P_COPY(0); \
\
	if (ARR_HASNULL(transarray) || \
		ARR_SIZE(transarray) != ARR_OVERHEAD_NONULLS(1) + sizeof(Int8TransTypeData)) \
		elog(ERROR, "expected 2-element int8 array"); \
\
	transdata = (Int8TransTypeData *) ARR_DATA_PTR(transarray); \
	transdata->count++; \
	transdata->sum += PG_GETARG_##ARGTYPE(1); \
\
	PG_RETURN_ARRAYTYPE_P(transarray); \
} \
extern int no_such_variable

make_avg_func(int1, INT8);
make_avg_func(uint1, UINT8);
make_avg_func(uint2, UINT16);
make_avg_func(uint4, UINT32);
make_avg_func(uint8, UINT64);