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Marc G. Fournier
1996-08-18 22:14:33 +00:00
parent 1960a3b965
commit 9848d3655d
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contrib/array/array_iterator.c Normal file
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/*
* array_iterator.c --
*
* This file defines a new group of operators which take an
* array and a scalar value, iterate a scalar operator over the
* elements of the array and the value and compute a result as
* the logical OR or AND of the results.
* For example array_int4eq returns true if some of the elements
* of an array of int4 is equal to the given value:
*
* array_int4eq({1,2,3}, 1) --> true
* array_int4eq({1,2,3}, 4) --> false
*
* If we have defined T array types and O scalar operators
* we can define T x O array operators, each of them has a name
* like "array_<basetype><operation>" and takes an array of type T
* iterating the operator O over all the elements. Note however
* that some of the possible combination are invalid, for example
* the array_int4_like because there is no like operator for int4.
* It is now possible to write queries which look inside the arrays:
*
* create table t(id int4[], txt text[]);
* select * from t where t.id *= 123;
* select * from t where t.txt *~ '[a-z]';
* select * from t where t.txt[1:3] **~ '[a-z]';
*
* Copyright (c) 1996, Massimo Dal Zotto <dz@cs.unitn.it>
*/
#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include "postgres.h"
#include "pg_type.h"
#include "miscadmin.h"
#include "syscache.h"
#include "access/xact.h"
#include "utils/builtins.h"
#include "utils/elog.h"
static int32
array_iterator(Oid elemtype, Oid proc, int and, ArrayType *array, Datum value)
{
HeapTuple typ_tuple;
TypeTupleForm typ_struct;
bool typbyval;
int typlen;
func_ptr proc_fn;
int pronargs;
int nitems, i, result;
int ndim, *dim;
char *p;
/* Sanity checks */
if ((array == (ArrayType *) NULL)
|| (ARR_IS_LO(array) == true)) {
/* elog(NOTICE, "array_iterator: array is null"); */
return (0);
}
ndim = ARR_NDIM(array);
dim = ARR_DIMS(array);
nitems = getNitems(ndim, dim);
if (nitems == 0) {
/* elog(NOTICE, "array_iterator: nitems = 0"); */
return (0);
}
/* Lookup element type information */
typ_tuple = SearchSysCacheTuple(TYPOID, ObjectIdGetDatum(elemtype),0,0,0);
if (!HeapTupleIsValid(typ_tuple)) {
elog(WARN,"array_iterator: cache lookup failed for type %d", elemtype);
return 0;
}
typ_struct = (TypeTupleForm) GETSTRUCT(typ_tuple);
typlen = typ_struct->typlen;
typbyval = typ_struct->typbyval;
/* Lookup the function entry point */
proc_fn == (func_ptr) NULL;
fmgr_info(proc, &proc_fn, &pronargs);
if ((proc_fn == NULL) || (pronargs != 2)) {
elog(WARN, "array_iterator: fmgr_info lookup failed for oid %d", proc);
return (0);
}
/* Scan the array and apply the operator to each element */
result = 0;
p = ARR_DATA_PTR(array);
for (i = 0; i < nitems; i++) {
if (typbyval) {
switch(typlen) {
case 1:
result = (int) (*proc_fn)(*p, value);
break;
case 2:
result = (int) (*proc_fn)(* (int16 *) p, value);
break;
case 3:
case 4:
result = (int) (*proc_fn)(* (int32 *) p, value);
break;
}
p += typlen;
} else {
result = (int) (*proc_fn)(p, value);
if (typlen > 0) {
p += typlen;
} else {
p += INTALIGN(* (int32 *) p);
}
}
if (result) {
if (!and) {
return (1);
}
} else {
if (and) {
return (0);
}
}
}
if (and && result) {
return (1);
} else {
return (0);
}
}
/*
* Iterators for type _text
*/
int32
array_texteq(ArrayType *array, char* value)
{
return array_iterator((Oid) 25, /* text */
(Oid) 67, /* texteq */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_texteq(ArrayType *array, char* value)
{
return array_iterator((Oid) 25, /* text */
(Oid) 67, /* texteq */
1, /* logical and */
array, (Datum)value);
}
int32
array_textregexeq(ArrayType *array, char* value)
{
return array_iterator((Oid) 25, /* text */
(Oid) 81, /* textregexeq */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_textregexeq(ArrayType *array, char* value)
{
return array_iterator((Oid) 25, /* text */
(Oid) 81, /* textregexeq */
1, /* logical and */
array, (Datum)value);
}
/*
* Iterators for type _char16. Note that the regexp operators
* take the second argument of type text.
*/
int32
array_char16eq(ArrayType *array, char* value)
{
return array_iterator((Oid) 20, /* char16 */
(Oid) 490, /* char16eq */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_char16eq(ArrayType *array, char* value)
{
return array_iterator((Oid) 20, /* char16 */
(Oid) 490, /* char16eq */
1, /* logical and */
array, (Datum)value);
}
int32
array_char16regexeq(ArrayType *array, char* value)
{
return array_iterator((Oid) 20, /* char16 */
(Oid) 700, /* char16regexeq */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_char16regexeq(ArrayType *array, char* value)
{
return array_iterator((Oid) 20, /* char16 */
(Oid) 700, /* char16regexeq */
1, /* logical and */
array, (Datum)value);
}
/*
* Iterators for type _int4
*/
int32
array_int4eq(ArrayType *array, int4 value)
{
return array_iterator((Oid) 23, /* int4 */
(Oid) 65, /* int4eq */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_int4eq(ArrayType *array, int4 value)
{
return array_iterator((Oid) 23, /* int4 */
(Oid) 65, /* int4eq */
1, /* logical and */
array, (Datum)value);
}
int32
array_int4gt(ArrayType *array, int4 value)
{
return array_iterator((Oid) 23, /* int4 */
(Oid) 147, /* int4gt */
0, /* logical or */
array, (Datum)value);
}
int32
array_all_int4gt(ArrayType *array, int4 value)
{
return array_iterator((Oid) 23, /* int4 */
(Oid) 147, /* int4gt */
1, /* logical and */
array, (Datum)value);
}