/
quantile.c
1146 lines (824 loc) · 29.3 KB
/
quantile.c
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/*
* quantile.c - Quantile aggregate function
* Copyright (C) Tomas Vondra, 2011
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* TODO Take care of the memory consumption (respect work_mem, flush
* the data to disk if more space is needed and use merge sort, i.e.
* something like the ORDER BY uses).
*/
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <sys/time.h>
#include <unistd.h>
#include <limits.h>
#include "postgres.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/numeric.h"
#include "utils/builtins.h"
#include "catalog/pg_type.h"
#include "nodes/execnodes.h"
#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif
#if (PG_VERSION_NUM >= 90000)
#define GET_AGG_CONTEXT(fname, fcinfo, aggcontext) \
if (! AggCheckCallContext(fcinfo, &aggcontext)) { \
elog(ERROR, "%s called in non-aggregate context", fname); \
}
#define CHECK_AGG_CONTEXT(fname, fcinfo) \
if (! AggCheckCallContext(fcinfo, NULL)) { \
elog(ERROR, "%s called in non-aggregate context", fname); \
}
#elseif (PG_VERSION_NUM >= 80400)
#define GET_AGG_CONTEXT(fname, fcinfo, aggcontext) \
if (fcinfo->context && IsA(fcinfo->context, AggState)) { \
aggcontext = ((AggState *) fcinfo->context)->aggcontext; \
} else if (fcinfo->context && IsA(fcinfo->context, WindowAggState)) { \
aggcontext = ((WindowAggState *) fcinfo->context)->wincontext; \
} else { \
elog(ERROR, "%s called in non-aggregate context", fname); \
aggcontext = NULL; \
}
#define CHECK_AGG_CONTEXT(fname, fcinfo) \
if (!(fcinfo->context && \
(IsA(fcinfo->context, AggState) || \
IsA(fcinfo->context, WindowAggState)))) \
{ \
elog(ERROR, "%s called in non-aggregate context", fname); \
}
#else
#define GET_AGG_CONTEXT(fname, fcinfo, aggcontext) \
if (fcinfo->context && IsA(fcinfo->context, AggState)) { \
aggcontext = ((AggState *) fcinfo->context)->aggcontext; \
} else { \
elog(ERROR, "%s called in non-aggregate context", fname); \
aggcontext = NULL; \
}
#define CHECK_AGG_CONTEXT(fname, fcinfo) \
if (!(fcinfo->context && \
(IsA(fcinfo->context, AggState)))) \
{ \
elog(ERROR, "%s called in non-aggregate context", fname); \
}
/* backward compatibility with 8.3 (macros copied mostly from src/include/access/tupmacs.h) */
#if SIZEOF_DATUM == 8
#define fetch_att(T,attbyval,attlen) \
( \
(attbyval) ? \
( \
(attlen) == (int) sizeof(Datum) ? \
*((Datum *)(T)) \
: \
( \
(attlen) == (int) sizeof(int32) ? \
Int32GetDatum(*((int32 *)(T))) \
: \
( \
(attlen) == (int) sizeof(int16) ? \
Int16GetDatum(*((int16 *)(T))) \
: \
( \
AssertMacro((attlen) == 1), \
CharGetDatum(*((char *)(T))) \
) \
) \
) \
) \
: \
PointerGetDatum((char *) (T)) \
)
#else /* SIZEOF_DATUM != 8 */
#define fetch_att(T,attbyval,attlen) \
( \
(attbyval) ? \
( \
(attlen) == (int) sizeof(int32) ? \
Int32GetDatum(*((int32 *)(T))) \
: \
( \
(attlen) == (int) sizeof(int16) ? \
Int16GetDatum(*((int16 *)(T))) \
: \
( \
AssertMacro((attlen) == 1), \
CharGetDatum(*((char *)(T))) \
) \
) \
) \
: \
PointerGetDatum((char *) (T)) \
)
#endif /* SIZEOF_DATUM == 8 */
#define att_addlength_pointer(cur_offset, attlen, attptr) \
( \
((attlen) > 0) ? \
( \
(cur_offset) + (attlen) \
) \
: (((attlen) == -1) ? \
( \
(cur_offset) + VARSIZE_ANY(attptr) \
) \
: \
( \
AssertMacro((attlen) == -2), \
(cur_offset) + (strlen((char *) (attptr)) + 1) \
)) \
)
#define att_align_nominal(cur_offset, attalign) \
( \
((attalign) == 'i') ? INTALIGN(cur_offset) : \
(((attalign) == 'c') ? (long) (cur_offset) : \
(((attalign) == 'd') ? DOUBLEALIGN(cur_offset) : \
( \
AssertMacro((attalign) == 's'), \
SHORTALIGN(cur_offset) \
))) \
)
#endif
#define SLICE_SIZE 1024
/* Structures used to keep the data - the 'elements' array is extended
* on the fly if needed. */
typedef struct struct_double {
int nquantiles;
int nelements;
int next;
double * quantiles;
double * elements;
} struct_double;
typedef struct struct_int32 {
int nquantiles;
int nelements;
int next;
double * quantiles;
int32 * elements;
} struct_int32;
typedef struct struct_int64 {
int nquantiles;
int nelements;
int next;
double * quantiles;
int64 * elements;
} struct_int64;
typedef struct struct_numeric {
int nquantiles;
int nelements;
int next;
double * quantiles;
Numeric * elements;
} struct_numeric;
/* comparators, used for qsort */
static int double_comparator(const void *a, const void *b);
static int int32_comparator(const void *a, const void *b);
static int int64_comparator(const void *a, const void *b);
static int numeric_comparator(const void *a, const void *b);
/* parse the quantiles array */
static double *
array_to_double(FunctionCallInfo fcinfo, ArrayType *v, int * len);
static Datum
double_to_array(FunctionCallInfo fcinfo, double * d, int len);
static Datum
int32_to_array(FunctionCallInfo fcinfo, int32 * d, int len);
static Datum
int64_to_array(FunctionCallInfo fcinfo, int64 * d, int len);
static Datum
numeric_to_array(FunctionCallInfo fcinfo, Numeric * d, int len);
/* prototypes */
PG_FUNCTION_INFO_V1(quantile_append_double_array);
PG_FUNCTION_INFO_V1(quantile_append_double);
PG_FUNCTION_INFO_V1(quantile_double_array);
PG_FUNCTION_INFO_V1(quantile_double);
PG_FUNCTION_INFO_V1(quantile_append_int32_array);
PG_FUNCTION_INFO_V1(quantile_append_int32);
PG_FUNCTION_INFO_V1(quantile_int32_array);
PG_FUNCTION_INFO_V1(quantile_int32);
PG_FUNCTION_INFO_V1(quantile_append_int64_array);
PG_FUNCTION_INFO_V1(quantile_append_int64);
PG_FUNCTION_INFO_V1(quantile_int64_array);
PG_FUNCTION_INFO_V1(quantile_int64);
PG_FUNCTION_INFO_V1(quantile_append_numeric_array);
PG_FUNCTION_INFO_V1(quantile_append_numeric);
PG_FUNCTION_INFO_V1(quantile_numeric_array);
PG_FUNCTION_INFO_V1(quantile_numeric);
Datum quantile_append_double_array(PG_FUNCTION_ARGS);
Datum quantile_append_double(PG_FUNCTION_ARGS);
Datum quantile_double_array(PG_FUNCTION_ARGS);
Datum quantile_double(PG_FUNCTION_ARGS);
Datum quantile_append_int32_array(PG_FUNCTION_ARGS);
Datum quantile_append_int32(PG_FUNCTION_ARGS);
Datum quantile_int32_array(PG_FUNCTION_ARGS);
Datum quantile_int32(PG_FUNCTION_ARGS);
Datum quantile_append_int64_array(PG_FUNCTION_ARGS);
Datum quantile_append_int64(PG_FUNCTION_ARGS);
Datum quantile_int64_array(PG_FUNCTION_ARGS);
Datum quantile_int64(PG_FUNCTION_ARGS);
Datum quantile_append_numeric_array(PG_FUNCTION_ARGS);
Datum quantile_append_numeric(PG_FUNCTION_ARGS);
Datum quantile_numeric_array(PG_FUNCTION_ARGS);
Datum quantile_numeric(PG_FUNCTION_ARGS);
/* These functions use a bit dirty trick to pass the data - the int
* value is actually a pointer to the array allocated in the parent
* memory context. A bit ugly but works fine.
*
* The memory consumption might be a problem, as all the values are
* kept in the memory - for example 1.000.000 of 8-byte values (bigint)
* requires about 8MB of memory.
*/
Datum
quantile_append_double(PG_FUNCTION_ARGS)
{
struct_double * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_double", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_double*)palloc(sizeof(struct_double));
data->elements = (double*)palloc(SLICE_SIZE*sizeof(double));
data->nelements = SLICE_SIZE;
data->next = 0;
data->quantiles = (double*)palloc(sizeof(double));
data->quantiles[0] = PG_GETARG_FLOAT8(2);
data->nquantiles = 1;
} else {
data = (struct_double*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
double element = PG_GETARG_FLOAT8(1);
if (data->next > data->nelements-1) {
data->elements = (double*)repalloc(data->elements, sizeof(double)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_double_array(PG_FUNCTION_ARGS)
{
struct_double * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_double_array", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_double*)palloc(sizeof(struct_double));
data->elements = (double*)palloc(SLICE_SIZE*sizeof(double));
data->nelements = SLICE_SIZE;
data->next = 0;
/* read the array of quantiles */
data->quantiles = array_to_double(fcinfo, PG_GETARG_ARRAYTYPE_P(2), &data->nquantiles);
} else {
data = (struct_double*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
double element = PG_GETARG_FLOAT8(1);
if (data->next > data->nelements-1) {
data->elements = (double*)repalloc(data->elements, sizeof(double)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_numeric(PG_FUNCTION_ARGS)
{
struct_numeric * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_numeric", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_numeric*)palloc(sizeof(struct_numeric));
data->elements = (Numeric*)palloc(SLICE_SIZE*sizeof(Numeric));
data->nelements = SLICE_SIZE;
data->next = 0;
data->quantiles = (double*)palloc(sizeof(double));
data->quantiles[0] = PG_GETARG_FLOAT8(2);
data->nquantiles = 1;
} else {
data = (struct_numeric*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
Numeric element = PG_GETARG_NUMERIC(1);
if (data->next > data->nelements-1) {
data->elements = (Numeric*)repalloc(data->elements, sizeof(Numeric)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_numeric_array(PG_FUNCTION_ARGS)
{
struct_numeric * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_numeric_array", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_numeric*)palloc(sizeof(struct_numeric));
data->elements = (Numeric*)palloc(SLICE_SIZE*sizeof(Numeric));
data->nelements = SLICE_SIZE;
data->next = 0;
/* read the array of quantiles */
data->quantiles = array_to_double(fcinfo, PG_GETARG_ARRAYTYPE_P(2), &data->nquantiles);
} else {
data = (struct_numeric*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
Numeric element = PG_GETARG_NUMERIC(1);
if (data->next > data->nelements-1) {
data->elements = (Numeric*)repalloc(data->elements, sizeof(Numeric)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_int32(PG_FUNCTION_ARGS)
{
struct_int32 * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_int32", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_int32*)palloc(sizeof(struct_int32));
data->quantiles = (double*)palloc(sizeof(double));
data->elements = (int32*)palloc(SLICE_SIZE*sizeof(int32));
data->nelements = SLICE_SIZE;
data->nquantiles = 1;
data->quantiles[0] = PG_GETARG_FLOAT8(2);
data->next = 0;
} else {
data = (struct_int32*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
int32 element = PG_GETARG_INT32(1);
if (data->next > data->nelements-1) {
data->elements = (int32*)repalloc(data->elements, sizeof(int32)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_int32_array(PG_FUNCTION_ARGS)
{
struct_int32 * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_int32_array", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_int32*)palloc(sizeof(struct_int32));
data->elements = (int32*)palloc(SLICE_SIZE*sizeof(int32));
data->nelements = SLICE_SIZE;
data->next = 0;
/* read the array of quantiles */
data->quantiles = array_to_double(fcinfo, PG_GETARG_ARRAYTYPE_P(2), &data->nquantiles);
} else {
data = (struct_int32*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
int32 element = PG_GETARG_INT32(1);
if (data->next > data->nelements-1) {
data->elements = (int32*)repalloc(data->elements, sizeof(int32)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_int64(PG_FUNCTION_ARGS)
{
struct_int64 * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_int64", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_int64*)palloc(sizeof(struct_int64));
data->quantiles = (double*)palloc(sizeof(double));
data->elements = (int64*)palloc(SLICE_SIZE*sizeof(int64));
data->nelements = SLICE_SIZE;
data->nquantiles = 1;
data->quantiles[0] = PG_GETARG_FLOAT8(2);
data->next = 0;
} else {
data = (struct_int64*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
int64 element = PG_GETARG_INT64(1);
if (data->next > data->nelements-1) {
data->elements = (int64*)repalloc(data->elements, sizeof(int64)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_append_int64_array(PG_FUNCTION_ARGS)
{
struct_int64 * data;
MemoryContext oldcontext;
MemoryContext aggcontext;
GET_AGG_CONTEXT("quantile_append_int64_array", fcinfo, aggcontext);
oldcontext = MemoryContextSwitchTo(aggcontext);
if (PG_ARGISNULL(0)) {
data = (struct_int64*)palloc(sizeof(struct_int64));
data->elements = (int64*)palloc(SLICE_SIZE*sizeof(int64));
data->nelements = SLICE_SIZE;
data->next = 0;
/* read the array of quantiles */
data->quantiles = array_to_double(fcinfo, PG_GETARG_ARRAYTYPE_P(2), &data->nquantiles);
} else {
data = (struct_int64*)PG_GETARG_POINTER(0);
}
/* ignore NULL values */
if (! PG_ARGISNULL(1)) {
int64 element = PG_GETARG_INT64(1);
if (data->next > data->nelements-1) {
data->elements = (int64*)repalloc(data->elements, sizeof(int64)*(data->nelements + SLICE_SIZE));
data->nelements = data->nelements + SLICE_SIZE;
}
data->elements[data->next++] = element;
}
MemoryContextSwitchTo(oldcontext);
PG_RETURN_POINTER(data);
}
Datum
quantile_double(PG_FUNCTION_ARGS)
{
int idx = 0;
double *result;
struct_double * data;
CHECK_AGG_CONTEXT("quantile_double", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_double*)PG_GETARG_POINTER(0);
result = palloc(data->nquantiles * sizeof(double));
qsort(data->elements, data->next, sizeof(double), &double_comparator);
if ((data->quantiles[0] > 0) && (data->quantiles[0] < 1)) {
idx = (int)ceil(data->next * data->quantiles[0]) - 1;
} else {
idx = 0;
}
PG_RETURN_FLOAT8(data->elements[idx]);
}
Datum
quantile_double_array(PG_FUNCTION_ARGS)
{
int i, idx = 0;
double * result;
struct_double * data;
CHECK_AGG_CONTEXT("quantile_double_array", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_double*)PG_GETARG_POINTER(0);
result = palloc(data->nquantiles * sizeof(double));
qsort(data->elements, data->next, sizeof(double), &double_comparator);
for (i = 0; i < data->nquantiles; i++) {
if ((data->quantiles[i] > 0) && (data->quantiles[i] < 1)) {
idx = (int)ceil(data->next * data->quantiles[i]) - 1;
} else if (data->quantiles[i] <= 0) {
idx = 0;
} else if (data->quantiles[i] >= 1) {
idx = data->next - 1;
}
result[i] = data->elements[idx];
}
return double_to_array(fcinfo, result, data->nquantiles);
}
Datum
quantile_int32(PG_FUNCTION_ARGS)
{
int idx;
struct_int32 * data;
CHECK_AGG_CONTEXT("quantile_int32", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_int32*)PG_GETARG_POINTER(0);
qsort(data->elements, data->next, sizeof(int32), &int32_comparator);
if (data->quantiles[0] > 0) {
idx = (int)ceil(data->next * data->quantiles[0]) - 1;
} else {
idx = 0;
}
PG_RETURN_INT32(data->elements[idx]);
}
Datum
quantile_int32_array(PG_FUNCTION_ARGS)
{
int i, idx = 0;
struct_int32 * data;
int32 * result;
CHECK_AGG_CONTEXT("quantile_int32_array", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_int32*)PG_GETARG_POINTER(0);
result = palloc(data->nquantiles * sizeof(int32));
qsort(data->elements, data->next, sizeof(int32), &int32_comparator);
for (i = 0; i < data->nquantiles; i++) {
if ((data->quantiles[i] > 0) && (data->quantiles[i] < 1)) {
idx = (int)ceil(data->next * data->quantiles[i]) - 1;
} else if (data->quantiles[i] <= 0) {
idx = 0;
} else if (data->quantiles[i] >= 1) {
idx = data->next - 1;
}
result[i] = data->elements[idx];
}
return int32_to_array(fcinfo, result, data->nquantiles);
}
Datum
quantile_int64(PG_FUNCTION_ARGS)
{
int idx;
struct_int64 * data;
CHECK_AGG_CONTEXT("quantile_int64", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_int64*)PG_GETARG_POINTER(0);
qsort(data->elements, data->next, sizeof(int64), &int64_comparator);
if (data->quantiles[0] > 0) {
idx = (int)ceil(data->next * data->quantiles[0]) - 1;
} else {
idx = 0;
}
PG_RETURN_INT64(data->elements[idx]);
}
Datum
quantile_int64_array(PG_FUNCTION_ARGS)
{
int i, idx = 0;
struct_int64 * data;
int64 * result;
CHECK_AGG_CONTEXT("quantile_int64_array", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_int64*)PG_GETARG_POINTER(0);
result = palloc(data->nquantiles * sizeof(int64));
qsort(data->elements, data->next, sizeof(int64), &int64_comparator);
for (i = 0; i < data->nquantiles; i++) {
if ((data->quantiles[i] > 0) && (data->quantiles[i] < 1)) {
idx = (int)ceil(data->next * data->quantiles[i]) - 1;
} else if (data->quantiles[i] <= 0) {
idx = 0;
} else if (data->quantiles[i] >= 1) {
idx = data->next - 1;
}
result[i] = data->elements[idx];
}
return int64_to_array(fcinfo, result, data->nquantiles);
}
Datum
quantile_numeric(PG_FUNCTION_ARGS)
{
int idx;
struct_numeric * data;
CHECK_AGG_CONTEXT("quantile_numeric", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_numeric*)PG_GETARG_POINTER(0);
qsort(data->elements, data->next, sizeof(Numeric), &numeric_comparator);
if (data->quantiles[0] > 0) {
idx = (int)ceil(data->next * data->quantiles[0]) - 1;
} else {
idx = 0;
}
PG_RETURN_NUMERIC(data->elements[idx]);
}
Datum
quantile_numeric_array(PG_FUNCTION_ARGS)
{
int i, idx = 0;
struct_numeric * data;
Numeric * result;
CHECK_AGG_CONTEXT("quantile_numeric_array", fcinfo);
if (PG_ARGISNULL(0)) {
PG_RETURN_NULL();
}
data = (struct_numeric*)PG_GETARG_POINTER(0);
result = palloc(data->nquantiles * sizeof(Numeric));
qsort(data->elements, data->next, sizeof(Numeric), &numeric_comparator);
for (i = 0; i < data->nquantiles; i++) {
if ((data->quantiles[i] > 0) && (data->quantiles[i] < 1)) {
idx = (int)ceil(data->next * data->quantiles[i]) - 1;
} else if (data->quantiles[i] <= 0) {
idx = 0;
} else if (data->quantiles[i] >= 1) {
idx = data->next - 1;
}
result[i] = data->elements[idx];
}
return numeric_to_array(fcinfo, result, data->nquantiles);
}
/* Comparators for the qsort() calls. */
static int double_comparator(const void *a, const void *b) {
double af = (*(double*)a);
double bf = (*(double*)b);
return (af > bf) - (af < bf);
}
static int int32_comparator(const void *a, const void *b) {
int32 af = (*(int32*)a);
int32 bf = (*(int32*)b);
return (af > bf) - (af < bf);
}
static int int64_comparator(const void *a, const void *b) {
int64 af = (*(int64*)a);
int64 bf = (*(int64*)b);
return (af > bf) - (af < bf);
}
static int numeric_comparator(const void *a, const void *b) {
FunctionCallInfoData fcinfo;
/* set params */
fcinfo.arg[0] = NumericGetDatum(*(Numeric*)a);
fcinfo.arg[1] = NumericGetDatum(*(Numeric*)b);
fcinfo.argnull[0] = false;
fcinfo.argnull[1] = false;
/* return the result */
return DatumGetInt32(numeric_cmp(&fcinfo));
}
/*
* Reading quantiles from an input array, based mostly on
* array_to_text_internal (it's a modified copy). This expects
* to receive a single-dimensional float8 array as input, fails
* otherwise.
*/
static double *
array_to_double(FunctionCallInfo fcinfo, ArrayType *v, int * len)
{
double *result;
int nitems,
*dims,
ndims;
Oid element_type;
int typlen;
bool typbyval;
char typalign;
char *p;
int i, idx = 0;
ArrayMetaState *my_extra;
ndims = ARR_NDIM(v);
dims = ARR_DIMS(v);
nitems = ArrayGetNItems(ndims, dims);
/* this is a special-purpose function for single-dimensional arrays */
if (ndims != 1) {
elog(ERROR, "error, array_to_double expects a single-dimensional array"
"(dims = %d)", ndims);
}
/* if there are no elements, set the length to 0 and return NULL */