Support Docs & Contrib

1 files changed, 251 insertions, 0 deletions

diff --git a/contrib/array/array_iterator.c b/contrib/array/array_iterator.c
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+++ b/contrib/array/array_iterator.c
@@ -0,0 +1,251 @@
+/*
+ * 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);
+}