udf_reg_3_func.cc

/* Copyright (c) 2017, 2025, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is designed to work with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have either included with
the program or referenced in the documentation.

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, version 2.0, for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */

/* This test component register 3 UDFsin the init method (install) and
 unregister them in deinit (uninstall). */

#include<mysql/components/component_implementation.h>
#include<mysql/components/service_implementation.h>
#include<mysql/components/services/udf_registration.h>
#include<sys/types.h>
#include<cctype>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>

REQUIRES_SERVICE_PLACEHOLDER(udf_registration);
REQUIRES_SERVICE_PLACEHOLDER(udf_registration_aggregate);

/***************************************************************************
** UDF double function.
** Arguments:
** initid Structure filled by xxx_init
** args The same structure as to xxx_init. This structure
** contains values for all parameters.
** Note that the functions MUST check and convert all
** to the type it wants! Null values are represented by
** a NULL pointer
** is_null If the result is null, one should store 1 here.
** error If something goes fatally wrong one should store 1 here.
**
** This function should return the result.
***************************************************************************/

boolmyfunc_double_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
unsigned i;

if (!args->arg_count) {
strcpy(message, "myfunc_double must have at least one argument");
returntrue;
 }
/*
 ** As this function wants to have everything as strings, force all arguments
 ** to strings.
*/
for (i = 0; i < args->arg_count; i++) args->arg_type[i] = STRING_RESULT;
 initid->maybe_null = true; /* The result may be null */
 initid->decimals = 2; /* We want 2 decimals in the result */
 initid->max_length = 6; /* 3 digits + . + 2 decimals */
returnfalse;
}

doublemyfunc_double(UDF_INIT *, UDF_ARGS *args, unsignedchar *is_null,
unsignedchar *) {
unsignedlong val = 0;
unsignedlong v = 0;
unsigned i, j;

for (i = 0; i < args->arg_count; i++) {
if (args->args[i] == nullptr) continue;
 val += args->lengths[i];
for (j = args->lengths[i]; j-- > 0;) v += args->args[i][j];
 }
if (val) return (double)v / (double)val;
 *is_null = 1;
return0.0;
}

/***************************************************************************
** UDF long long function.
** Arguments:
** initid Return value from xxxx_init
** args The same structure as to xxx_init. This structure
** contains values for all parameters.
** Note that the functions MUST check and convert all
** to the type it wants! Null values are represented by
** a NULL pointer
** is_null If the result is null, one should store 1 here.
** error If something goes fatally wrong one should store 1 here.
**
** This function should return the result as a long long
***************************************************************************/

/* This function returns the sum of all arguments */

longlongmyfunc_int(UDF_INIT *, UDF_ARGS *args, unsignedchar *,
unsignedchar *) {
longlong val = 0;
unsigned i;

for (i = 0; i < args->arg_count; i++) {
if (args->args[i] == nullptr) continue;
switch (args->arg_type[i]) {
case STRING_RESULT: /* Add string lengths */
 val += args->lengths[i];
break;
case INT_RESULT: /* Add numbers */
 val += *((longlong *)args->args[i]);
break;
case REAL_RESULT: /* Add numbers as long long */
 val += (longlong)*((double *)args->args[i]);
break;
default:
break;
 }
 }
return val;
}

boolmyfunc_int_init(UDF_INIT *, UDF_ARGS *, char *) { returnfalse; }

/***************************************************************************
** Syntax for the new aggregate commands are:
** create aggregate function <function_name> returns {string|real|integer}
** soname <name_of_shared_library>
**
** Syntax for avgcost: avgcost( t.quantity, t.price )
** with t.quantity=integer, t.price=double
** (this example is provided by Andreas F. Bobak <bobak@relog.ch>)
****************************************************************************/

structavgcost_data {
unsignedlonglong count;
longlong totalquantity;
double totalprice;
};

/*
** Average Cost Aggregate Function.
*/
boolavgcost_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
structavgcost_data *data;

if (args->arg_count != 2) {
strcpy(message,
"wrong number of arguments: AVGCOST() requires two arguments");
returntrue;
 }

if ((args->arg_type[0] != INT_RESULT) || (args->arg_type[1] != REAL_RESULT)) {
strcpy(message,
"wrong argument type: AVGCOST() requires an INT and a REAL");
returntrue;
 }

/*
 ** force arguments to double.
*/
/*args->arg_type[0] = REAL_RESULT;
 args->arg_type[1] = REAL_RESULT;*/

 initid->maybe_null = false; /* The result may be null */
 initid->decimals = 4; /* We want 4 decimals in the result */
 initid->max_length = 20; /* 6 digits + . + 10 decimals */

if (!(data = new (std::nothrow) avgcost_data)) {
strcpy(message, "Couldn't allocate memory");
returntrue;
 }
 data->totalquantity = 0;
 data->totalprice = 0.0;

 initid->ptr = (char *)data;

returnfalse;
}

voidavgcost_deinit(UDF_INIT *initid) {
void *void_ptr = initid->ptr;
auto *data = static_cast<avgcost_data *>(void_ptr);
delete data;
}

/* This is needed to get things to work in MySQL 4.1.1 and above */

voidavgcost_clear(UDF_INIT *initid, unsignedchar *, unsignedchar *) {
auto *data = (structavgcost_data *)initid->ptr;
 data->totalprice = 0.0;
 data->totalquantity = 0;
 data->count = 0;
}

voidavgcost_add(UDF_INIT *initid, UDF_ARGS *args, unsignedchar *,
unsignedchar *) {
if (args->args[0] && args->args[1]) {
auto *data = (structavgcost_data *)initid->ptr;
longlongconst quantity = *((longlong *)args->args[0]);
longlongconst newquantity = data->totalquantity + quantity;
double price = *((double *)args->args[1]);

 data->count++;

if (((data->totalquantity >= 0) && (quantity < 0)) ||
 ((data->totalquantity < 0) && (quantity > 0))) {
/*
 ** passing from + to - or from - to +
*/
if (((quantity < 0) && (newquantity < 0)) ||
 ((quantity > 0) && (newquantity > 0))) {
 data->totalprice = price * (double)newquantity;
 }
/*
 ** sub q if totalq > 0
 ** add q if totalq < 0
*/
else {
 price = data->totalprice / (double)data->totalquantity;
 data->totalprice = price * (double)newquantity;
 }
 data->totalquantity = newquantity;
 } else {
 data->totalquantity += quantity;
 data->totalprice += price * (double)quantity;
 }

if (data->totalquantity == 0) data->totalprice = 0.0;
 }
}

doubleavgcost(UDF_INIT *initid, UDF_ARGS *, unsignedchar *is_null,
unsignedchar *) {
auto *data = (structavgcost_data *)initid->ptr;
if (!data->count || !data->totalquantity) {
 *is_null = 1;
return0.0;
 }

 *is_null = 0;
return data->totalprice / (double)data->totalquantity;
}

/**************************************************************************************/

staticmysql_service_status_tinit() {
bool ret_int = false;
 ret_int = mysql_service_udf_registration->udf_register(
"myfunc_int", INT_RESULT, (Udf_func_any)myfunc_int, myfunc_int_init,
nullptr);
// myfunc_double_deinit);
bool ret_double = false;
 ret_double = mysql_service_udf_registration->udf_register(
"myfunc_double", REAL_RESULT, (Udf_func_any)myfunc_double,
 myfunc_double_init, nullptr);
bool ret_avgcost = false;
 ret_avgcost = mysql_service_udf_registration_aggregate->udf_register(
"avgcost", REAL_RESULT, (Udf_func_any)avgcost, avgcost_init,
 avgcost_deinit, avgcost_add, avgcost_clear);
return ret_int && ret_double && ret_avgcost;
}

staticmysql_service_status_tdeinit() {
int was_present = 0;
for (int i = 0; i < 10; i++) {
 mysql_service_udf_registration->udf_unregister("myfunc_double",
 &was_present);
if (was_present != 0) break;
 }

 was_present = 0;
for (int i = 0; i < 10; i++) {
 mysql_service_udf_registration->udf_unregister("myfunc_int", &was_present);
if (was_present != 0) break;
 }

 was_present = 0;
for (int i = 0; i < 10; i++) {
 mysql_service_udf_registration->udf_unregister("avgcost", &was_present);
if (was_present != 0) break;
 }
returnfalse;
}

BEGIN_COMPONENT_PROVIDES(test_udf_registration)
END_COMPONENT_PROVIDES();

BEGIN_COMPONENT_REQUIRES(test_udf_registration)
REQUIRES_SERVICE(udf_registration),
 REQUIRES_SERVICE(udf_registration_aggregate), END_COMPONENT_REQUIRES();

BEGIN_COMPONENT_METADATA(test_udf_registration)
METADATA("mysql.author", "Oracle Corporation"),
 METADATA("mysql.license", "GPL"), METADATA("test_property", "1"),
 END_COMPONENT_METADATA();

DECLARE_COMPONENT(test_udf_registration, "mysql:test_udf_registration")
init, deinit END_DECLARE_COMPONENT();

DECLARE_LIBRARY_COMPONENTS &COMPONENT_REF(test_udf_registration)
 END_DECLARE_LIBRARY_COMPONENTS