postgres/src/backend/utils/adt/array_userfuncs.c
Tom Lane 730840c9b6 First phase of work on array improvements. ARRAY[x,y,z] constructor
expressions, ARRAY(sub-SELECT) expressions, some array functions.
Polymorphic functions using ANYARRAY/ANYELEMENT argument and return
types.  Some regression tests in place, documentation is lacking.
Joe Conway, with some kibitzing from Tom Lane.
2003-04-08 23:20:04 +00:00

437 lines
11 KiB
C

/*-------------------------------------------------------------------------
*
* array_userfuncs.c
* Misc user-visible array support functions
*
* Copyright (c) 2003, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/array_userfuncs.c,v 1.1 2003/04/08 23:20:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "utils/array.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
/*-----------------------------------------------------------------------------
* singleton_array :
* Form a multi-dimensional array given one starting element.
*
* - first argument is the datum with which to build the array
* - second argument is the number of dimensions the array should have;
* defaults to 1 if no second argument is provided
*----------------------------------------------------------------------------
*/
Datum
singleton_array(PG_FUNCTION_ARGS)
{
Oid elem_type = get_fn_expr_argtype(fcinfo, 0);
int ndims;
if (elem_type == InvalidOid)
elog(ERROR, "Cannot determine input datatype");
if (PG_NARGS() == 2)
ndims = PG_GETARG_INT32(1);
else
ndims = 1;
PG_RETURN_ARRAYTYPE_P(create_singleton_array(elem_type,
PG_GETARG_DATUM(0),
ndims));
}
/*-----------------------------------------------------------------------------
* array_push :
* push an element onto either end of a one-dimensional array
*----------------------------------------------------------------------------
*/
Datum
array_push(PG_FUNCTION_ARGS)
{
ArrayType *v;
Datum newelem;
int *dimv,
*lb;
ArrayType *result;
int indx;
bool isNull;
Oid element_type;
int16 typlen;
bool typbyval;
char typalign;
Oid arg0_typeid = get_fn_expr_argtype(fcinfo, 0);
Oid arg1_typeid = get_fn_expr_argtype(fcinfo, 1);
Oid arg0_elemid;
Oid arg1_elemid;
if (arg0_typeid == InvalidOid || arg1_typeid == InvalidOid)
elog(ERROR, "array_push: cannot determine input data types");
arg0_elemid = get_element_type(arg0_typeid);
arg1_elemid = get_element_type(arg1_typeid);
if (arg0_elemid != InvalidOid)
{
v = PG_GETARG_ARRAYTYPE_P(0);
element_type = ARR_ELEMTYPE(v);
newelem = PG_GETARG_DATUM(1);
}
else if (arg1_elemid != InvalidOid)
{
v = PG_GETARG_ARRAYTYPE_P(1);
element_type = ARR_ELEMTYPE(v);
newelem = PG_GETARG_DATUM(0);
}
else
{
/* Shouldn't get here given proper type checking in parser */
elog(ERROR, "array_push: neither input type is an array");
PG_RETURN_NULL(); /* keep compiler quiet */
}
/* Sanity check: do we have a one-dimensional array */
if (ARR_NDIM(v) != 1)
elog(ERROR, "Arrays greater than one-dimension are not supported");
lb = ARR_LBOUND(v);
dimv = ARR_DIMS(v);
if (arg0_elemid != InvalidOid)
{
/* append newelem */
int ub = dimv[0] + lb[0] - 1;
indx = ub + 1;
}
else
{
/* prepend newelem */
indx = lb[0] - 1;
}
get_typlenbyvalalign(element_type, &typlen, &typbyval, &typalign);
result = array_set(v, 1, &indx, newelem, -1,
typlen, typbyval, typalign, &isNull);
PG_RETURN_ARRAYTYPE_P(result);
}
/*-----------------------------------------------------------------------------
* array_cat :
* concatenate two nD arrays to form an (n+1)D array, or
* push an (n-1)D array onto the end of an nD array
*----------------------------------------------------------------------------
*/
Datum
array_cat(PG_FUNCTION_ARGS)
{
ArrayType *v1, *v2;
int *dims, *lbs, ndims, ndatabytes, nbytes;
int *dims1, *lbs1, ndims1, ndatabytes1;
int *dims2, *lbs2, ndims2, ndatabytes2;
char *dat1, *dat2;
Oid element_type;
Oid element_type1;
Oid element_type2;
ArrayType *result;
v1 = PG_GETARG_ARRAYTYPE_P(0);
v2 = PG_GETARG_ARRAYTYPE_P(1);
/*
* We must have one of the following combinations of inputs:
* 1) two arrays with ndims1 == ndims2
* 2) ndims1 == ndims2 - 1
* 3) ndims1 == ndims2 + 1
*/
ndims1 = ARR_NDIM(v1);
ndims2 = ARR_NDIM(v2);
if (ndims1 != ndims2 && ndims1 != ndims2 - 1 && ndims1 != ndims2 + 1)
elog(ERROR, "Cannot concatenate incompatible arrays of %d and "
"%d dimensions", ndims1, ndims2);
element_type1 = ARR_ELEMTYPE(v1);
element_type2 = ARR_ELEMTYPE(v2);
/* Do we have a matching element types */
if (element_type1 != element_type2)
elog(ERROR, "Cannot concatenate incompatible arrays with element "
"type %u and %u", element_type1, element_type2);
/* OK, use it */
element_type = element_type1;
/* get argument array details */
lbs1 = ARR_LBOUND(v1);
lbs2 = ARR_LBOUND(v2);
dims1 = ARR_DIMS(v1);
dims2 = ARR_DIMS(v2);
dat1 = ARR_DATA_PTR(v1);
dat2 = ARR_DATA_PTR(v2);
ndatabytes1 = ARR_SIZE(v1) - ARR_OVERHEAD(ndims1);
ndatabytes2 = ARR_SIZE(v2) - ARR_OVERHEAD(ndims2);
if (ndims1 == ndims2)
{
/*
* resulting array has two element outer array made up of input
* argument arrays
*/
int i;
ndims = ndims1 + 1;
dims = (int *) palloc(ndims * sizeof(int));
lbs = (int *) palloc(ndims * sizeof(int));
dims[0] = 2; /* outer array made up of two input arrays */
lbs[0] = 1; /* start lower bound at 1 */
for (i = 0; i < ndims1; i++)
{
if (dims1[i] != dims2[i] || lbs1[i] != lbs2[i])
elog(ERROR, "Cannot concatenate arrays with differing dimensions");
dims[i + 1] = dims1[i];
lbs[i + 1] = lbs1[i];
}
}
else if (ndims1 == ndims2 - 1)
{
/*
* resulting array has the second argument as the outer array,
* with the first argument appended to the front of the outer
* dimension
*/
int i;
ndims = ndims2;
dims = dims2;
lbs = lbs2;
/* increment number of elements in outer array */
dims[0] += 1;
/* make sure the added element matches our existing elements */
for (i = 0; i < ndims1; i++)
{
if (dims1[i] != dims[i + 1] || lbs1[i] != lbs[i + 1])
elog(ERROR, "Cannot concatenate arrays with differing dimensions");
}
}
else /* (ndims1 == ndims2 + 1) */
{
/*
* resulting array has the first argument as the outer array,
* with the second argument appended to the end of the outer
* dimension
*/
int i;
ndims = ndims1;
dims = dims1;
lbs = lbs1;
/* increment number of elements in outer array */
dims[0] += 1;
/* make sure the added element matches our existing elements */
for (i = 0; i < ndims2; i++)
{
if (dims2[i] != dims[i + 1] || lbs2[i] != lbs[i + 1])
elog(ERROR, "Cannot concatenate arrays with differing dimensions");
}
}
/* build the result array */
ndatabytes = ndatabytes1 + ndatabytes2;
nbytes = ndatabytes + ARR_OVERHEAD(ndims);
result = (ArrayType *) palloc(nbytes);
result->size = nbytes;
result->ndim = ndims;
result->flags = 0;
result->elemtype = element_type;
memcpy(ARR_DIMS(result), dims, ndims * sizeof(int));
memcpy(ARR_LBOUND(result), lbs, ndims * sizeof(int));
/* data area is arg1 then arg2 */
memcpy(ARR_DATA_PTR(result), dat1, ndatabytes1);
memcpy(ARR_DATA_PTR(result) + ndatabytes1, dat2, ndatabytes2);
PG_RETURN_ARRAYTYPE_P(result);
}
/*----------------------------------------------------------------------------
* array_accum :
* accumulator to build a 1-D array from input values -- this can be used
* to create custom aggregates.
*
* This function is not marked strict, so we have to be careful about nulls.
*----------------------------------------------------------------------------
*/
Datum
array_accum(PG_FUNCTION_ARGS)
{
/* return NULL if both arguments are NULL */
if (PG_ARGISNULL(0) && PG_ARGISNULL(1))
PG_RETURN_NULL();
/* create a new 1-D array from the new element if the array is NULL */
if (PG_ARGISNULL(0))
{
Oid tgt_type = get_fn_expr_rettype(fcinfo);
Oid tgt_elem_type;
if (tgt_type == InvalidOid)
elog(ERROR, "Cannot determine target array type");
tgt_elem_type = get_element_type(tgt_type);
if (tgt_elem_type == InvalidOid)
elog(ERROR, "Target type is not an array");
PG_RETURN_ARRAYTYPE_P(create_singleton_array(tgt_elem_type,
PG_GETARG_DATUM(1),
1));
}
/* return the array if the new element is NULL */
if (PG_ARGISNULL(1))
PG_RETURN_ARRAYTYPE_P(PG_GETARG_ARRAYTYPE_P_COPY(0));
/*
* Otherwise this is equivalent to array_push. We hack the call a little
* so that array_push can see the fn_expr information.
*/
return array_push(fcinfo);
}
/*-----------------------------------------------------------------------------
* array_assign :
* assign an element of an array to a new value and return the
* redefined array
*----------------------------------------------------------------------------
*/
Datum
array_assign(PG_FUNCTION_ARGS)
{
ArrayType *v;
int idx_to_chg;
Datum newelem;
int *dimv,
*lb, ub;
ArrayType *result;
bool isNull;
Oid element_type;
int16 typlen;
bool typbyval;
char typalign;
v = PG_GETARG_ARRAYTYPE_P(0);
idx_to_chg = PG_GETARG_INT32(1);
newelem = PG_GETARG_DATUM(2);
/* Sanity check: do we have a one-dimensional array */
if (ARR_NDIM(v) != 1)
elog(ERROR, "Arrays greater than one-dimension are not supported");
lb = ARR_LBOUND(v);
dimv = ARR_DIMS(v);
ub = dimv[0] + lb[0] - 1;
if (idx_to_chg < lb[0] || idx_to_chg > ub)
elog(ERROR, "Cannot alter nonexistent array element: %d", idx_to_chg);
element_type = ARR_ELEMTYPE(v);
/* Sanity check: do we have a non-zero element type */
if (element_type == 0)
elog(ERROR, "Invalid array element type: %u", element_type);
get_typlenbyvalalign(element_type, &typlen, &typbyval, &typalign);
result = array_set(v, 1, &idx_to_chg, newelem, -1,
typlen, typbyval, typalign, &isNull);
PG_RETURN_ARRAYTYPE_P(result);
}
/*-----------------------------------------------------------------------------
* array_subscript :
* return specific element of an array
*----------------------------------------------------------------------------
*/
Datum
array_subscript(PG_FUNCTION_ARGS)
{
ArrayType *v;
int idx;
int *dimv,
*lb, ub;
Datum result;
bool isNull;
Oid element_type;
int16 typlen;
bool typbyval;
char typalign;
v = PG_GETARG_ARRAYTYPE_P(0);
idx = PG_GETARG_INT32(1);
/* Sanity check: do we have a one-dimensional array */
if (ARR_NDIM(v) != 1)
elog(ERROR, "Arrays greater than one-dimension are not supported");
lb = ARR_LBOUND(v);
dimv = ARR_DIMS(v);
ub = dimv[0] + lb[0] - 1;
if (idx < lb[0] || idx > ub)
elog(ERROR, "Cannot return nonexistent array element: %d", idx);
element_type = ARR_ELEMTYPE(v);
/* Sanity check: do we have a non-zero element type */
if (element_type == 0)
elog(ERROR, "Invalid array element type: %u", element_type);
get_typlenbyvalalign(element_type, &typlen, &typbyval, &typalign);
result = array_ref(v, 1, &idx, -1, typlen, typbyval, typalign, &isNull);
PG_RETURN_DATUM(result);
}
/*
* actually does the work for singleton_array(), and array_accum() if it is
* given a null input array.
*/
ArrayType *
create_singleton_array(Oid element_type, Datum element, int ndims)
{
Datum dvalues[1];
int16 typlen;
bool typbyval;
char typalign;
int dims[MAXDIM];
int lbs[MAXDIM];
int i;
if (element_type == 0)
elog(ERROR, "Invalid array element type: %u", element_type);
if (ndims < 1 || ndims > MAXDIM)
elog(ERROR, "Invalid number of dimensions %d", ndims);
dvalues[0] = element;
for (i = 0; i < ndims; i++)
{
dims[i] = 1;
lbs[i] = 1;
}
get_typlenbyvalalign(element_type, &typlen, &typbyval, &typalign);
return construct_md_array(dvalues, ndims, dims, lbs, element_type,
typlen, typbyval, typalign);
}