firebird-mirror/examples/udr/Functions.cpp

/*
 *  The contents of this file are subject to the Initial
 *  Developer's Public License Version 1.0 (the "License");
 *  you may not use this file except in compliance with the
 *  License. You may obtain a copy of the License at
 *  http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
 *
 *  Software distributed under the License is distributed AS IS,
 *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
 *  See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Original Code was created by Adriano dos Santos Fernandes
 *  for the Firebird Open Source RDBMS project.
 *
 *  Copyright (c) 2008 Adriano dos Santos Fernandes <adrianosf@gmail.com>
 *  and all contributors signed below.
 *
 *  All Rights Reserved.
 *  Contributor(s): ______________________________________.
 */

#include "UdrCppExample.h"

using namespace Firebird;


//------------------------------------------------------------------------------


/***
create function wait_event (
    event_name varchar(31) character set utf8 not null
) returns integer not null
    external name 'udrcpp_example!wait_event'
    engine udr;
***/
FB_UDR_BEGIN_FUNCTION(wait_event)
	FB_UDR_MESSAGE(InMessage,
		(FB_VARCHAR(31 * 4), name)
	);

	FB_UDR_MESSAGE(OutMessage,
		(FB_INTEGER, result)
	);

	FB_UDR_EXECUTE_FUNCTION
	{
		char* s = new char[in->name.length + 1];
		memcpy(s, in->name.str, in->name.length);
		s[in->name.length] = '\0';

		unsigned char* eveBuffer;
		unsigned char* eveResult;
		int eveLen = isc_event_block(&eveBuffer, &eveResult, 1, s);

		delete [] s;

		ISC_STATUS_ARRAY statusVector = {0};
		isc_db_handle dbHandle = Helper::getIscDbHandle(status, context);
		ISC_ULONG counter = 0;

		FbException::check(isc_wait_for_event(
			statusVector, &dbHandle, eveLen, eveBuffer, eveResult), status, statusVector);
		isc_event_counts(&counter, eveLen, eveBuffer, eveResult);
		FbException::check(isc_wait_for_event(
			statusVector, &dbHandle, eveLen, eveBuffer, eveResult), status, statusVector);
		isc_event_counts(&counter, eveLen, eveBuffer, eveResult);

		isc_free((char*) eveBuffer);
		isc_free((char*) eveResult);

		out->resultNull = FB_FALSE;
		out->result = counter;
	}
FB_UDR_END_FUNCTION


/***
create function sum_args (
    n1 integer,
    n2 integer,
    n3 integer
) returns integer
    external name 'udrcpp_example!sum_args'
    engine udr;
***/
FB_UDR_BEGIN_FUNCTION(sum_args)
	// Without InMessage/OutMessage definitions, messages will be byte-based.

	FB_UDR_CONSTRUCTOR
		// , inCount(0)
	{
		// Get input metadata.
		AutoRelease<IMessageMetadata> inMetadata(metadata->getInputMetadata(status));

		// Get count of input parameters.
		inCount = inMetadata->getCount(status);

		inNullOffsets.reset(new unsigned[inCount]);
		inOffsets.reset(new unsigned[inCount]);

		for (unsigned i = 0; i < inCount; ++i)
		{
			// Get null offset of the i-th input parameter.
			inNullOffsets[i] = inMetadata->getNullOffset(status, i);

			// Get the offset of the i-th input parameter.
			inOffsets[i] = inMetadata->getOffset(status, i);
		}

		// Get output metadata.
		AutoRelease<IMessageMetadata> outMetadata(metadata->getOutputMetadata(status));

		// Get null offset of the return value.
		outNullOffset = outMetadata->getNullOffset(status, 0);

		// Get offset of the return value.
		outOffset = outMetadata->getOffset(status, 0);
	}

	// This function requires the INTEGER parameters and return value, otherwise it will crash.
	// Metadata is inspected dynamically (in execute). This is not the fastest method.
	FB_UDR_EXECUTE_FUNCTION
	{
		*(ISC_SHORT*) (out + outNullOffset) = FB_FALSE;

		// Get a reference to the return value.
		ISC_LONG& ret = *(ISC_LONG*) (out + outOffset);

		// The return value is automatically initialized to 0.
		///ret = 0;

		for (unsigned i = 0; i < inCount; ++i)
		{
			// If the i-th input parameter is NULL, set the output to NULL and finish.
			if (*(ISC_SHORT*) (in + inNullOffsets[i]))
			{
				*(ISC_SHORT*) (out + outNullOffset) = FB_TRUE;
				return;
			}

			// Read the i-th input parameter value and sum it in the referenced return value.
			ret += *(ISC_LONG*) (in + inOffsets[i]);
		}
	}

	unsigned inCount;
	AutoArrayDelete<unsigned> inNullOffsets;
	AutoArrayDelete<unsigned> inOffsets;
	unsigned outNullOffset;
	unsigned outOffset;
FB_UDR_END_FUNCTION


/***
create function mult (
    a decfloat(34) not null,
    b decfloat(34) not null
) returns decfloat(34) not null
    external name 'udrcpp_example!mult'
    engine udr;
***/
FB_UDR_BEGIN_FUNCTION(mult)
	// Without InMessage/OutMessage definitions, messages will be byte-based.

	FB_UDR_CONSTRUCTOR
	{
		AutoRelease<IMessageMetadata> inMetadata(metadata->getInputMetadata(status));
		aOffset = inMetadata->getOffset(status, 0);
		bOffset = inMetadata->getOffset(status, 1);

		AutoRelease<IMessageMetadata> outMetadata(metadata->getOutputMetadata(status));
		outOffset = outMetadata->getOffset(status, 0);
		outNullOffset = outMetadata->getNullOffset(status, 0);

		df34 = master->getUtilInterface()->getDecFloat34(status);
	}

	// This function requires the INTEGER parameters and return value, otherwise it will crash.
	// Metadata is inspected dynamically (in execute). This is not the fastest method.
	FB_UDR_EXECUTE_FUNCTION
	{
		struct ExampleBCD
		{
			unsigned char bcd[IDecFloat34::BCD_SIZE];
			int sign, exp;

			void load(void* from, IDecFloat34* df34)
			{
				df34->toBcd((FB_DEC34*) from, &sign, bcd, &exp);
			}

			void store(void* to, IDecFloat34* df34) const
			{
				df34->fromBcd(sign, bcd, exp, (FB_DEC34*) to);
			}
		};

		ExampleBCD a, b, rc;
		a.load(in + aOffset, df34);
		b.load(in + bOffset, df34);

		// multiply (trivial example - a lot of features are missing)
		rc.sign = a.sign ^ b.sign;
		rc.exp = a.exp + b.exp;

		unsigned char buf[2 * IDecFloat34::BCD_SIZE + 1];
		memset(buf, 0, sizeof(buf));

		for (unsigned i = IDecFloat34::BCD_SIZE; i--;)
		{
			for (unsigned j = IDecFloat34::BCD_SIZE; j--;)
			{
				unsigned char v = a.bcd[i] * b.bcd[j] + buf[i + j + 1];
				buf[i + j + 1] = v % 10;
				buf[i + j] += v / 10;
			}
		}

		unsigned offset = 0;

		for (; offset < IDecFloat34::BCD_SIZE; ++offset)
		{
			if (buf[offset])
				break;
		}

		memcpy(rc.bcd, buf + offset, sizeof rc.bcd);
		rc.exp += (IDecFloat34::BCD_SIZE - offset);

		rc.store(out + outOffset, df34);
		*(ISC_SHORT*) (out + outNullOffset) = FB_FALSE;
	}

	unsigned aOffset, bOffset, outOffset, outNullOffset;
	IDecFloat34* df34;
FB_UDR_END_FUNCTION


//------------------------------------------------------------------------------


// This should be used in only one of the UDR library files.
// Build must export firebird_udr_plugin function.
FB_UDR_IMPLEMENT_ENTRY_POINT