cloop FirebirdInterface.idl pascal Firebird.pas Firebird --uses SysUtils \
  --interfaceFile Pascal.interface.pas \
  --implementationFile Pascal.implementation.pas \
  --exceptionClass FbException --prefix I \
  --functionsFile fb_get_master_interface.pas

awk -f Pascal.Constants.awk consts_pub.h > const.pas

{CREATE [OR ALTER] | RECREATE} FUNCTION funcname [(<inparam> [, <inparam> ...])]
RETURNS <type> [COLLATE collation] [DETERMINISTIC]
EXTERNAL NAME <extname> ENGINE <engine>
[AS <extbody>]


<inparam> ::= <param_decl> [{= | DEFAULT} <value>]

<value> ::=  {literal | NULL | context_var}

<param_decl> ::= paramname <type> [NOT NULL] [COLLATE collation]

<extname> ::= '<module name>!<routine name>[!<misc info>]'

<type> ::= <datatype> | [TYPE OF] domain | TYPE OF COLUMN rel.col

<datatype> ::=
    {SMALLINT | INT[EGER] | BIGINT}
  | BOOLEAN
  | {FLOAT | DOUBLE PRECISION}
  | {DATE | TIME | TIMESTAMP}
  | {DECIMAL | NUMERIC} [(precision [, scale])]
  | {CHAR | CHARACTER | CHARACTER VARYING | VARCHAR} [(size)]
    [CHARACTER SET charset]
  | {NCHAR | NATIONAL CHARACTER | NATIONAL CHAR} [VARYING] [(size)]
  | BLOB [SUB_TYPE {subtype_num | subtype_name}]
    [SEGMENT SIZE seglen] [CHARACTER SET charset]
  | BLOB [(seglen [, subtype_num])]

ALTER FUNCTION funcname [(<inparam> [, <inparam> ...])]
RETURNS <type> [COLLATE collation] [DETERMINISTIC]
EXTERNAL NAME <extname> ENGINE <engine>
[AS <extbody>]

<extname> ::= '<module name>!<routine name>[!<misc info>]'

DROP FUNCTION funcname

create function sum_args (
    n1 integer,
    n2 integer,
    n3 integer
)
returns integer
external name 'udrcpp_example!sum_args'
engine udr;

create or alter function regex_replace (
  regex varchar(60),
  str varchar(60),
  replacement varchar(60)
)
returns varchar(60)
external name 'org.firebirdsql.fbjava.examples.fbjava_example.FbRegex.replace(
      String, String, String)'
engine java;

{CREATE [OR ALTER] | RECREATE} PROCEDURE procname [(<inparam> [, <inparam> ...])]
RETURNS (<outparam> [, <outparam> ...])
EXTERNAL NAME <extname> ENGINE <engine>
[AS <extbody>]

<inparam> ::= <param_decl> [{= | DEFAULT} <value>]

<outparam>  ::=  <param_decl>

<value> ::=  {literal | NULL | context_var}

<param_decl> ::= paramname <type> [NOT NULL] [COLLATE collation]

<extname> ::= '<module name>!<routine name>[!<misc info>]'

<type> ::= <datatype> | [TYPE OF] domain | TYPE OF COLUMN rel.col

<datatype> ::=
    {SMALLINT | INT[EGER] | BIGINT}
  | BOOLEAN
  | {FLOAT | DOUBLE PRECISION}
  | {DATE | TIME | TIMESTAMP}
  | {DECIMAL | NUMERIC} [(precision [, scale])]
  | {CHAR | CHARACTER | CHARACTER VARYING | VARCHAR} [(size)]
    [CHARACTER SET charset]
  | {NCHAR | NATIONAL CHARACTER | NATIONAL CHAR} [VARYING] [(size)]
  | BLOB [SUB_TYPE {subtype_num | subtype_name}]
    [SEGMENT SIZE seglen] [CHARACTER SET charset]
  | BLOB [(seglen [, subtype_num])]

ALTER PROCEDURE procname [(<inparam> [, <inparam> ...])]
RETURNS (<outparam> [, <outparam> ...])
EXTERNAL NAME <extname> ENGINE <engine>
[AS <extbody>]

DROP PROCEDURE procname

create procedure gen_rows_pascal (
    start_n integer not null,
    end_n integer not null
)
returns (
    result integer not null
)
external name 'pascaludr!gen_rows'
engine udr;

create or alter procedure write_log (
  message varchar(100)
)
external name 'pascaludr!write_log'
engine udr;

create or alter procedure employee_pgsql (
  -- Firebird 3.0.0 has a bug with external procedures without parameters
  dummy integer = 1
)
returns (
  id type of column employee.id,
  name type of column employee.name
)
external name 'org.firebirdsql.fbjava.examples.fbjava_example.FbJdbc
    .executeQuery()!jdbc:postgresql:employee|postgres|postgres'
engine java
as 'select * from employee';

{CREATE [OR ALTER] | RECREATE} PACKAGE package_name
AS
BEGIN
  [<package_item> ...]
END

{CREATE | RECREATE} PACKAGE BODY package_name
AS
BEGIN
  [<package_item> ...]
  [<package_body_item> ...]
END

<package_item> ::=
    <function_decl>;
  | <procedure_decl>;

<function_decl> ::=
  FUNCTION func_name [(<in_params>)]
  RETURNS <type> [COLLATE collation]
  [DETERMINISTIC]

<procedure_decl> ::=
  PROCEDURE proc_name [(<in_params>)]
  [RETURNS (<out_params>)]

<package_body_item> ::=
    <function_impl>
  | <procedure_impl>

<function_impl> ::=
  FUNCTION func_name [(<in_impl_params>)]
  RETURNS <type> [COLLATE collation]
  [DETERMINISTIC]
  <routine body>

<procedure_impl> ::=
  PROCEDURE proc_name [(<in_impl_params>)]
  [RETURNS (<out_params>)]
  <routine body>

<routine body> ::= <sql routine body> | <external body reference>

<sql routine body> ::=
  AS
    [<declarations>]
  BEGIN
    [<PSQL_statements>]
  END

<declarations> ::= <declare_item> [<declare_item> ...]

<declare_item> ::=
    <declare_var>;
  | <declare_cursor>;
  | <subroutine declaration>;
  | <subroutine implimentation>

<subroutine declaration> ::= <subfunc_decl> | <subproc_decl>

<subroutine implimentation> ::= <subfunc_impl> | <subproc_impl>

<external body reference> ::=
  EXTERNAL NAME <extname> ENGINE <engine> [AS <extbody>]

<extname> ::= '<module name>!<routine name>[!<misc info>]'

SET TERM ^;

CREATE OR ALTER PACKAGE REGEXP
AS
BEGIN
  PROCEDURE preg_match(
      APattern VARCHAR(8192), ASubject VARCHAR(8192))
    RETURNS (Matches VARCHAR(8192));

  FUNCTION preg_is_match(
      APattern VARCHAR(8192), ASubject VARCHAR(8192))
    RETURNS BOOLEAN;

  FUNCTION preg_replace(
      APattern VARCHAR(8192),
      AReplacement VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS VARCHAR(8192);

  PROCEDURE preg_split(
      APattern VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS (Lines VARCHAR(8192));

  FUNCTION preg_quote(
      AStr VARCHAR(8192),
      ADelimiter CHAR(10) DEFAULT NULL)
    RETURNS VARCHAR(8192);
END^

RECREATE PACKAGE BODY REGEXP
AS
BEGIN
  PROCEDURE preg_match(
      APattern VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS (Matches VARCHAR(8192))
    EXTERNAL NAME 'PCRE!preg_match' ENGINE UDR;

  FUNCTION preg_is_match(
      APattern VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS BOOLEAN
  AS
  BEGIN
    RETURN EXISTS(
      SELECT * FROM preg_match(:APattern, :ASubject));
  END

  FUNCTION preg_replace(
      APattern VARCHAR(8192),
      AReplacement VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS VARCHAR(8192)
    EXTERNAL NAME 'PCRE!preg_replace' ENGINE UDR;

  PROCEDURE preg_split(
      APattern VARCHAR(8192),
      ASubject VARCHAR(8192))
    RETURNS (Lines VARCHAR(8192))
    EXTERNAL NAME 'PCRE!preg_split' ENGINE UDR;

  FUNCTION preg_quote(
      AStr VARCHAR(8192),
      ADelimiter CHAR(10))
    RETURNS VARCHAR(8192)
    EXTERNAL NAME 'PCRE!preg_quote' ENGINE UDR;
END^

SET TERM ;^

{CREATE [OR ALTER] | RECREATE} TRIGGER trigname
{
    <relation_trigger_legacy>
  | <relation_trigger_sql2003>
  | <database_trigger>
  | <ddl_trigger>
}
<external-body>

<external-body> ::=
  EXTERNAL NAME <extname> ENGINE <engine>
  [AS <extbody>]

<relation_trigger_legacy> ::=
  FOR {tablename | viewname}
  [ACTIVE | INACTIVE]
  {BEFORE | AFTER} <mutation_list>
  [POSITION number]

<relation_trigger_sql2003> ::=
  [ACTIVE | INACTIVE]
  {BEFORE | AFTER} <mutation_list>
  [POSITION number]
  ON {tablename | viewname}

<database_trigger> ::=
  [ACTIVE | INACTIVE]
  ON db_event
  [POSITION number]

<ddl_trigger> ::=
  [ACTIVE | INACTIVE]
  {BEFORE | AFTER} <ddl_events>
  [POSITION number]

<mutation_list> ::= <mutation> [OR <mutation> [OR <mutation>]]

<mutation> ::= INSERT | UPDATE | DELETE

<db_event> ::=
    CONNECT
  | DISCONNECT
  | TRANSACTION START
  | TRANSACTION COMMIT
  | TRANSACTION ROLLBACK


<ddl_events> ::=
    ANY DDL STATEMENT
  | <ddl_event_item> [{OR <ddl_event_item>} ...]

<ddl_event_item> ::=
    CREATE TABLE | ALTER TABLE | DROP TABLE
  | CREATE PROCEDURE | ALTER PROCEDURE | DROP PROCEDURE
  | CREATE FUNCTION | ALTER FUNCTION | DROP FUNCTION
  | CREATE TRIGGER | ALTER TRIGGER | DROP TRIGGER
  | CREATE EXCEPTION | ALTER EXCEPTION | DROP EXCEPTION
  | CREATE VIEW | ALTER VIEW | DROP VIEW
  | CREATE DOMAIN | ALTER DOMAIN | DROP DOMAIN
  | CREATE ROLE | ALTER ROLE | DROP ROLE
  | CREATE SEQUENCE | ALTER SEQUENCE | DROP SEQUENCE
  | CREATE USER | ALTER USER | DROP USER
  | CREATE INDEX | ALTER INDEX | DROP INDEX
  | CREATE COLLATION | DROP COLLATION
  | ALTER CHARACTER SET
  | CREATE PACKAGE | ALTER PACKAGE | DROP PACKAGE
  | CREATE PACKAGE BODY | DROP PACKAGE BODY
  | CREATE MAPPING | ALTER MAPPING | DROP MAPPING

ALTER TRIGGER trigname {
[ACTIVE | INACTIVE]
[
    {BEFORE | AFTER} {<mutation_list> | <ddl_events>}
  | ON db_event
]
[POSITION number]
[<external-body>]

<external-body> ::=
  EXTERNAL NAME <extname> ENGINE <engine>
  [AS <extbody>]

<extname> ::= '<module name>!<routine name>[!<misc info>]'

<mutation_list> ::= <mutation> [OR <mutation> [OR <mutation>]]

<mutation> ::= { INSERT | UPDATE | DELETE }

DROP TRIGGER trigname

create database 'c:\temp\slave.fdb';

create table persons (
    id integer not null,
    name varchar(60) not null,
    address varchar(60),
    info blob sub_type text
);

commit;

create database 'c:\temp\master.fdb';

create table persons (
    id integer not null,
    name varchar(60) not null,
    address varchar(60),
    info blob sub_type text
);

create table replicate_config (
    name varchar(31) not null,
    data_source varchar(255) not null
);

insert into replicate_config (name, data_source)
   values ('ds1', 'c:\temp\slave.fdb');

create trigger persons_replicate
after insert on persons
external name 'udrcpp_example!replicate!ds1'
engine udr;

unit UdrInit;

{$IFDEF FPC}
  {$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses
  Firebird;

// entry point for the External Engine of the UDR module
function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;

implementation

uses
  SumArgsFunc;

var
  myUnloadFlag: Boolean;
  theirUnloadFlag: BooleanPtr;

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // register our functions
  AUdrPlugin.registerFunction(AStatus, 'sum_args',
    TSumArgsFunctionFactory.Create());
  // register our procedures
  //AUdrPlugin.registerProcedure(AStatus, 'sum_args_proc',
  //  TSumArgsProcedureFactory.Create());
  //AUdrPlugin.registerProcedure(AStatus, 'gen_rows', TGenRowsFactory.Create());
  // registering our triggers
  //AUdrPlugin.registerTrigger(AStatus, 'test_trigger',
  //  TMyTriggerFactory.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

initialization

myUnloadFlag := false;

finalization

if ((theirUnloadFlag <> nil) and not myUnloadFlag) then
  theirUnloadFlag^ := true;

end.

...
  if (:new.B IS NULL) THEN
    :new.B = :new.A + 1;
...

unit SumArgsFunc;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses
  Firebird;

{ *********************************************************
    create function sum_args (
      n1 integer,
      n2 integer,
      n3 integer
    ) returns integer
    external name 'myudr!sum_args'
    engine udr;
 ********************************************************* }

type
  // the structure to which the input message will be mapped
  TSumArgsInMsg = record
    n1: Integer;
    n1Null: WordBool;
    n2: Integer;
    n2Null: WordBool;
    n3: Integer;
    n3Null: WordBool;
  end;
  PSumArgsInMsg = ^TSumArgsInMsg;

  // the structure to which the output message will be mapped
  TSumArgsOutMsg = record
    result: Integer;
    resultNull: WordBool;
  end;
  PSumArgsOutMsg = ^TSumArgsOutMsg;

  // Factory for instantiating the external function TSumArgsFunction
  TSumArgsFunctionFactory = class(IUdrFunctionFactoryImpl)
    // Called when the factory is destroyed
    procedure dispose(); override;

    { Executed each time an external function is loaded into the metadata cache.
       Used to change the format of the input and output messages.

      @param(AStatus status vector)
      @param(AContext External function execution context)
      @param(AMetadata External Function Metadata)
      @param(AInBuilder Message builder for input metadata)
      @param(AOutBuilder Message builder for output metadata)
    }
    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    { Creating a new external function instance TSumArgsFunction

      @param(AStatus status vector)
      @param(AContext External function execution context)
      @param(AMetadata External Function Metadata)
      @returns(Экземпляр external function)
    }
    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;

  // External function TSumArgsFunction.
  TSumArgsFunction = class(IExternalFunctionImpl)
    // Called when the function instance is destroyed
    procedure dispose(); override;

    { This method is called just before execute and tells
       kernel our requested character set to exchange data internally
       this method. During this call, the context uses the character set
       obtained from ExternalEngine::getCharSet.

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AName Character set name)
      @param(AName Character set name length)
    }
    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    { Executing an external function

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AInMsg Pointer to input message)
      @param(AOutMsg Pointer to output message)
    }
    procedure execute(AStatus: IStatus; AContext: IExternalContext;
      AInMsg: Pointer; AOutMsg: Pointer); override;
  end;

implementation

{ TSumArgsFunctionFactory }

procedure TSumArgsFunctionFactory.dispose;
begin
  Destroy;
end;

function TSumArgsFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := TSumArgsFunction.Create();
end;

procedure TSumArgsFunctionFactory.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TSumArgsFunction }

procedure TSumArgsFunction.dispose;
begin
  Destroy;
end;

procedure TSumArgsFunction.execute(AStatus: IStatus; AContext: IExternalContext;
  AInMsg, AOutMsg: Pointer);
var
  xInput: PSumArgsInMsg;
  xOutput: PSumArgsOutMsg;
begin
  // convert pointers to input and output to typed ones
  xInput := PSumArgsInMsg(AInMsg);
  xOutput := PSumArgsOutMsg(AOutMsg);
  // by default, the output argument is NULL, so set it to nullFlag
  xOutput^.resultNull := True;
  // if one of the arguments is NULL, then the result is NULL
  // otherwise, we calculate the sum of the arguments
  with xInput^ do
  begin
    if not (n1Null or n2Null or n3Null) then
    begin
      xOutput^.result := n1 + n2 + n3;
      // if there is a result, then reset the NULL flag
      xOutput^.resultNull := False;
    end;
  end;
end;

procedure TSumArgsFunction.getCharSet(AStatus: IStatus;
  AContext: IExternalContext; AName: PAnsiChar; ANameSize: Cardinal);
begin
end;

end.

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // register our functions
  AUdrPlugin.registerFunction(AStatus, 'sum_args',
    TSumArgsFunctionFactory.Create());
  // register our procedures
  AUdrPlugin.registerProcedure(AStatus, 'sum_args_proc',
    TSumArgsProcedureFactory.Create());
  //AUdrPlugin.registerProcedure(AStatus, 'gen_rows', TGenRowsFactory.Create());
  // register our triggers
  //AUdrPlugin.registerTrigger(AStatus, 'test_trigger',
  // TMyTriggerFactory.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

unit SumArgsProc;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses
  Firebird;

  { **********************************************************

    create procedure sp_sum_args (
      n1 integer,
      n2 integer,
      n3 integer
    ) returns (result integer)
    external name 'myudr!sum_args_proc'
    engine udr;

    ********************************************************* }
type
  // The structure of which the input message will be displayed
  TSumArgsInMsg = record
    n1: Integer;
    n1Null: WordBool;
    n2: Integer;
    n2Null: WordBool;
    n3: Integer;
    n3Null: WordBool;
  end;
  PSumArgsInMsg = ^TSumArgsInMsg;

  // The structure for which the output will be displayed
  TSumArgsOutMsg = record
    result: Integer;
    resultNull: WordBool;
  end;
  PSumArgsOutMsg = ^TSumArgsOutMsg;

  // Factory to create a copy of the external TSUMARGSPROCEDURE procedure
  TSumArgsProcedureFactory = class(IUdrProcedureFactoryImpl)
    // Called when the factory is destroyed
    procedure dispose(); override;

    { It is performed each time when loading the external procedure in the cache of metadata
       Used to change the input and output format.

      @param(AStatus Status vector)
      @param(AContext The context of the external procedure)
      @param(AMetadata Metadata of the external procedure)
      @param(AInBuilder Message builder for input metadata)
      @param(AOutBuilder Message builder for weekend metadata)
    }
    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    { Creating a new copy of the external procedure TSumArgsProcedure

      @param(AStatus Status vector)
      @param(AContext The context of the external procedure)
      @param(AMetadata Metadata of the external procedure)
      @returns(Экземпляр external procedure)
    }
    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalProcedure; override;
  end;

  TSumArgsProcedure = class(IExternalProcedureImpl)
  public
    // Called when destroying a copy of the procedure
    procedure dispose(); override;

    { This method is called just before open and tells the kernel
      our requested character set to communicate within this
      method. During this call, the context uses the character set
      obtained from ExternalEngine::getCharSet.

      @param(AStatus Status vector)
      @param(AContext The context of external function)
      @param(AName The name of the set of characters)
      @param(AName The length of the name of the set of characters)
    }
    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    { External procedure

      @param(AStatus Status vector)
      @param(AContext The context of external function)
      @param(AInMsg Input message pointer)
      @param(AOutMsg Output indicator)
      @returns(Data set for a selective procedure or
                Nil for the procedures)
    }
    function open(AStatus: IStatus; AContext: IExternalContext; AInMsg: Pointer;
      AOutMsg: Pointer): IExternalResultSet; override;
  end;

implementation

{ TSumArgsProcedureFactory }

procedure TSumArgsProcedureFactory.dispose;
begin
  Destroy;
end;

function TSumArgsProcedureFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalProcedure;
begin
  Result := TSumArgsProcedure.create;
end;

procedure TSumArgsProcedureFactory.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata; AInBuilder,
  AOutBuilder: IMetadataBuilder);
begin

end;

{ TSumArgsProcedure }

procedure TSumArgsProcedure.dispose;
begin
  Destroy;
end;

procedure TSumArgsProcedure.getCharSet(AStatus: IStatus;
  AContext: IExternalContext; AName: PAnsiChar; ANameSize: Cardinal);
begin

end;

function TSumArgsProcedure.open(AStatus: IStatus; AContext: IExternalContext;
  AInMsg, AOutMsg: Pointer): IExternalResultSet;
var
  xInput: PSumArgsInMsg;
  xOutput: PSumArgsOutMsg;
begin
  // The set of data for the procedures performed is not necessary
  Result := nil;
  // We convert the signs to the input and access to the typized
  xInput := PSumArgsInMsg(AInMsg);
  xOutput := PSumArgsOutMsg(AOutMsg);
  // By default, the output argument = NULL, and therefore we expose him nullflag
  xOutput^.resultNull := True;
  // If one of the arguments NULL means the result NULL
  // Otherwise, we consider the amount of arguments
  with xInput^ do
  begin
    if not (n1Null or n2Null or n3Null) then
    begin
      xOutput^.result := n1 + n2 + n3;
      // since there is a result, then drop the NULL flag
      xOutput^.resultNull := False;
    end;
  end;
end;

end.

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // We register our functions
  AUdrPlugin.registerFunction(AStatus, 'sum_args',
    TSumArgsFunctionFactory.Create());
  // We register our procedures
  AUdrPlugin.registerProcedure(AStatus, 'sum_args_proc',
    TSumArgsProcedureFactory.Create());
  AUdrPlugin.registerProcedure(AStatus, 'gen_rows', TGenRowsFactory.Create());
  // We register our triggers
  //AUdrPlugin.registerTrigger(AStatus, 'test_trigger',
  //  TMyTriggerFactory.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

unit GenRowsProc;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses
  Firebird, SysUtils;

type
  { **********************************************************

    create procedure gen_rows (
      start  integer,
      finish integer
    ) returns (n integer)
    external name 'myudr!gen_rows'
    engine udr;

    ********************************************************* }

  TInput = record
    start: Integer;
    startNull: WordBool;
    finish: Integer;
    finishNull: WordBool;
  end;
  PInput = ^TInput;

  TOutput = record
    n: Integer;
    nNull: WordBool;
  end;
  POutput = ^TOutput;

  // Factory for creating an instance of the external procedure TGenRowsProcedure
   TGenRowsFactory = class(IUdrProcedureFactoryImpl)
     // Called when the factory is destroyed
     procedure dispose(); override;

     { Executed each time an external function is loaded into the metadata cache.
       Used to change the format of the input and output messages.

       @param(AStatus Status vector)
       @param(AContext External function execution context)
       @param(AMetadata External function metadata)
       @param(AInBuilder Message builder for input metadata)
       @param(AOutBuilder Message builder for output metadata)
     }
     procedure setup(AStatus: IStatus; AContext: IExternalContext;
       AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
       AOutBuilder: IMetadataBuilder); override;

     { Create a new instance of the external procedure TGenRowsProcedure

       @param(AStatus Status vector)
       @param(AContext External function execution context)
       @param(AMetadata External function metadata)
       @returns(External function instance)
     }
     function newItem(AStatus: IStatus; AContext: IExternalContext;
       AMetadata: IRoutineMetadata): IExternalProcedure; override;
   end;

   // External procedure TGenRowsProcedure.
   TGenRowsProcedure = class(IExternalProcedureImpl)
   public
     // Called when the procedure instance is destroyed
     procedure dispose(); override;

     { This method is called just before open and tells
       to the kernel our requested set of characters to exchange data within this
       method. During this call, the context uses the character set obtained from
       ExternalEngine::getCharSet.

       @param(AStatus Status vector)
       @param(AContext External function execution context)
       @param(AName Character set name)
       @param(AName Character set name length)
     }
     procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
       AName: PAnsiChar; ANameSize: cardinal); override;

     { Execution of external procedure

       @param(AStatus Status vector)
       @param(AContext External function execution context)
       @param(AInMsg Pointer to input message)
       @param(AOutMsg Pointer to output message)
       @returns(Data set for selective procedure or
                nil for run procedures)
     }
     function open(AStatus: IStatus; AContext: IExternalContext; AInMsg: Pointer;
       AOutMsg: Pointer): IExternalResultSet; override;
   end;

   // Output data set for the TGenRowsProcedure procedure
   TGenRowsResultSet = class(IExternalResultSetImpl)
     Input: PInput;
     Output: POutput;

     // Called when the dataset instance is destroyed
     procedure dispose(); override;

     { Retrieve the next record from the dataset. Somewhat analogous to
       SUSPEND. In this method, the next record from the data set should
       be prepared.

       @param(AStatus Status vector)
       @returns(True if the dataset has an entry to retrieve,
                False if there are no more entries)
     }
     function fetch(AStatus: IStatus): Boolean; override;
   end;

implementation

{ TGenRowsFactory }

procedure TGenRowsFactory.dispose;
begin
   Destroy;
end;

function TGenRowsFactory.newItem(AStatus: IStatus; AContext: IExternalContext;
   AMetadata: IRoutineMetadata): IExternalProcedure;
begin
   Result := TGenRowsProcedure.create;
end;

procedure TGenRowsFactory.setup(AStatus: IStatus; AContext: IExternalContext;
   AMetadata: IRoutineMetadata; AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TGenRowsProcedure }

procedure TGenRowsProcedure.dispose;
begin
   Destroy;
end;

procedure TGenRowsProcedure.getCharSet(AStatus: IStatus;
   AContext: IExternalContext; AName: PAnsiChar; ANameSize: cardinal);
begin

end;

function TGenRowsProcedure.open(AStatus: IStatus; AContext: IExternalContext;
   AInMsg, AOutMsg: Pointer): IExternalResultSet;
begin
   Result := TGenRowsResultSet.create;
   with TGenRowsResultSet(Result) do
   begin
     Input := AInMsg;
     Output := AOutMsg;
   end;

   // if one of the input arguments is NULL, return nothing
   if PInput(AInMsg).startNull or PInput(AInMsg).finishNull then
   begin
     POutput(AOutMsg).nNull := True;
// intentionally set the output so that
// TGenRowsResultSet.fetch method returned false
     Output.n := Input.finish;
     exit;
   end;
   // checks
   if PInput(AInMsg).start > PInput(AInMsg).finish then
     raise Exception.Create('First parameter greater then second parameter.');

   with TGenRowsResultSet(Result) do
   begin
     // initial value
     Output.nNull := False;
     Output.n := Input.start - 1;
   end;
end;

{ TGenRowsResultSet }

procedure TGenRowsResultSet.dispose;
begin
   Destroy;
end;

// If it returns True, then the next record from the data set is retrieved.
// If it returns False, then the records in the data set are over
// new values in the output vector are calculated each time
// when calling this method
function TGenRowsResultSet.fetch(AStatus: IStatus): Boolean;
begin
  Inc(Output.n);
  Result := (Output.n <= Input.finish);
end;

end.

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
   AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
   // register our functions
   AUdrPlugin.registerFunction(AStatus, 'sum_args',
     TSumArgsFunctionFactory.Create());
   // register our procedures
   AUdrPlugin.registerProcedure(AStatus, 'sum_args_proc',
     TSumArgsProcedureFactory.Create());
   AUdrPlugin.registerProcedure(AStatus, 'gen_rows', TGenRowsFactory.Create());
   // register our triggers
   AUdrPlugin.registerTrigger(AStatus, 'test_trigger',
     TMyTriggerFactory.Create());

   theirUnloadFlag := AUnloadFlagLocal;
   Result := @myUnloadFlag;
end;

unit TestTrigger;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses
  Firebird, SysUtils;

type
  { **********************************************************
    create table test (
      id int generated by default as identity,
      a int,
      b int,
      name varchar(100),
      constraint pk_test primary key(id)
    );

    create or alter trigger tr_test_biu for test
    active before insert or update position 0
    external name 'myudr!test_trigger'
    engine udr;
  }

  // structure for displaying NEW.* and OLD.* messages
  // must match the field set of the test table
  TFieldsMessage = record
    Id: Integer;
    IdNull: WordBool;
    A: Integer;
    ANull: WordBool;
    B: Integer;
    BNull: WordBool;
    Name: record
      Length: Word;
      Value: array [0 .. 399] of AnsiChar;
    end;
    NameNull: WordBool;
  end;

  PFieldsMessage = ^TFieldsMessage;

  // Factory for instantiating external trigger TMyTrigger
  TMyTriggerFactory = class(IUdrTriggerFactoryImpl)
    // Called when the factory is destroyed
    procedure dispose(); override;

    { Executed each time an external trigger is loaded into the metadata cache.
      Used to change the message format for fields.

      @param(AStatus Status vector)
      @param(AContext External trigger execution context)
      @param(AMetadata External trigger metadata)
      @param(AFieldsBuilder Message builder for table fields)
    }
    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AFieldsBuilder: IMetadataBuilder); override;

    { Creating a new instance of the external trigger TMyTrigger

      @param(AStatus Status vector)
      @param(AContext External trigger execution context)
      @param(AMetadata External trigger metadata)
      @returns(Instance of external trigger)
    }
    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalTrigger; override;
  end;

  TMyTrigger = class(IExternalTriggerImpl)
    // Called when the trigger is destroyed
    procedure dispose(); override;

    { This method is called just before execute and tells
      kernel our requested character set to exchange data internally
      this method. During this call, the context uses the character set
      obtained from ExternalEngine::getCharSet.

      @param(AStatus Status vector)
      @param(AContext External trigger execution context)
      @param(AName Character set name)
      @param(AName Character set name length)
    }
    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;

      AName: PAnsiChar; ANameSize: Cardinal); override;

    { trigger execution TMyTrigger

      @param(AStatus Status vector)
      @param(AContext External trigger execution context)
      @param(AAction Action (current event) trigger)
      @param(AOldMsg Message for old field values :OLD.*)
      @param(ANewMsg Message for new field values :NEW.*)
    }
    procedure execute(AStatus: IStatus; AContext: IExternalContext;
      AAction: Cardinal; AOldMsg: Pointer; ANewMsg: Pointer); override;
  end;

implementation

{ TMyTriggerFactory }

procedure TMyTriggerFactory.dispose;
begin
  Destroy;
end;

function TMyTriggerFactory.newItem(AStatus: IStatus; AContext: IExternalContext;
  AMetadata: IRoutineMetadata): IExternalTrigger;
begin
  Result := TMyTrigger.create;
end;

procedure TMyTriggerFactory.setup(AStatus: IStatus; AContext: IExternalContext;
  AMetadata: IRoutineMetadata; AFieldsBuilder: IMetadataBuilder);
begin

end;

{ TMyTrigger }

procedure TMyTrigger.dispose;
begin
  Destroy;
end;

procedure TMyTrigger.execute(AStatus: IStatus; AContext: IExternalContext;
  AAction: Cardinal; AOldMsg, ANewMsg: Pointer);
var
  xOld, xNew: PFieldsMessage;
begin
  // xOld := PFieldsMessage(AOldMsg);
  xNew := PFieldsMessage(ANewMsg);
  case AAction of
    IExternalTrigger.ACTION_INSERT:
      begin
        if xNew.BNull and not xNew.ANull then
        begin
          xNew.B := xNew.A + 1;
          xNew.BNull := False;
        end;
      end;

    IExternalTrigger.ACTION_UPDATE:
      begin
        if xNew.BNull and not xNew.ANull then
        begin
          xNew.B := xNew.A + 1;
          xNew.BNull := False;
        end;
      end;

    IExternalTrigger.ACTION_DELETE:
      begin

      end;
  end;
end;

procedure TMyTrigger.getCharSet(AStatus: IStatus; AContext: IExternalContext;
  AName: PAnsiChar; ANameSize: Cardinal);
begin

end;

end.

TMyStruct = record
  <var_1>: <type_1>;
  <nullIndicator_1>: WordBool;
  <var_2>: <type_1>;
  <nullIndicator_2>: WordBool;
  ...
  <var_N>: <type_1>;
  <nullIndicator_N>: WordBool;
end;
PMyStruct = ^TMyStruct;

function SUM_ARGS(A SMALLINT, B INTEGER) RETURNS BIGINT
....

TInput = record
  A: Smallint;
  ANull: WordBool;
  B: Integer;
  BNull: WordBool;
end;
PInput = ^TInput;

TOutput = record
  Value: Int64;
  Null: WordBool;
end;
POutput = ^TOutput;

function SUM_ARGS(A NUMERIC(4, 2), B NUMERIC(9, 3)) RETURNS NUMERIC(18, 6)
....

TInput = record
  A: Smallint;
  ANull: WordBool;
  B: Integer;
  BNull: WordBool;
end;
PInput = ^TInput;

TOutput = record
  Value: Int64;
  Null: WordBool;
end;
POutput = ^TOutput;

procedure SOME_PROC(A CHAR(3) CHARACTER SET WIN1251, B VARCHAR(10) CHARACTER SET UTF8)
....

TInput = record
  A: array[0..2] of AnsiChar;
  ANull: WordBool;
  B: record
    Length: Smallint;
    Value: array[0..39] of AnsiChar;
  end;
  BNull: WordBool;
end;
PInput = ^TInput;

  // Factory for instantiating the external function TSumArgsFunction
  TSumArgsFunctionFactory = class(IUdrFunctionFactoryImpl)
    // Called when the factory is destroyed
    procedure dispose(); override;

    { Executed each time an external function is loaded into the metadata cache

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AMetadata External function metadata)
      @param(AInBuilder Message builder for input metadata)
      @param(AOutBuilder Message builder for output metadata)
    }
    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    { Creating a new instance of the external function TSumArgsFunction

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AMetadata External function metadata)
      @returns(External function instance)
    }
    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;

  // External function TSumArgsFunction.
  TSumArgsFunction = class(IExternalFunctionImpl)
  private
    FMetadata: IRoutineMetadata;
  public
    property Metadata: IRoutineMetadata read FMetadata write FMetadata;
  public
    // Called when the function instance is destroyed
    procedure dispose(); override;

    { This method is called just before execute and tells the kernel
      our requested character set to communicate within this method.
      During this call, the context uses the character set obtained
      from ExternalEngine::getCharSet.

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AName Character set name)
      @param(AName Character set name length)
    }
    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    { Executing an external function

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AInMsg Pointer to input message)
      @param(AOutMsg Pointer to output message)
    }
    procedure execute(AStatus: IStatus; AContext: IExternalContext;
      AInMsg: Pointer; AOutMsg: Pointer); override;
  end;
........................

{ TSumArgsFunctionFactory }

procedure TSumArgsFunctionFactory.dispose;
begin
  Destroy;
end;

function TSumArgsFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := TSumArgsFunction.Create();
  with Result as TSumArgsFunction do
  begin
    Metadata := AMetadata;
  end;
end;

procedure TSumArgsFunctionFactory.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

........................

procedure TSumArgsFunction.execute(AStatus: IStatus; AContext: IExternalContext;
  AInMsg, AOutMsg: Pointer);
var
  n1, n2, n3: Integer;
  n1Null, n2Null, n3Null: WordBool;
  Result: Integer;
  resultNull: WordBool;
  xInputMetadata, xOutputMetadata: IMessageMetadata;
begin
  xInputMetadata := FMetadata.getInputMetadata(AStatus);
  xOutputMetadata := FMetadata.getOutputMetadata(AStatus);
  try
    // get the values of the input arguments by their offsets
    n1 := PInteger(PByte(AInMsg) + xInputMetadata.getOffset(AStatus, 0))^;
    n2 := PInteger(PByte(AInMsg) + xInputMetadata.getOffset(AStatus, 1))^;
    n3 := PInteger(PByte(AInMsg) + xInputMetadata.getOffset(AStatus, 2))^;
    // get values of null indicators of input arguments by their offsets
    n1Null := PWordBool(PByte(AInMsg) +
      xInputMetadata.getNullOffset(AStatus, 0))^;
    n2Null := PWordBool(PByte(AInMsg) +
      xInputMetadata.getNullOffset(AStatus, 1))^;
    n3Null := PWordBool(PByte(AInMsg) +
      xInputMetadata.getNullOffset(AStatus, 2))^;
    //by default, the output argument is NULL, so we set it to nullFlag
    resultNull := True;
    Result := 0;
    // if one of the arguments is NULL, then the result is NULL
    // otherwise, we calculate the sum of the arguments
    if not(n1Null or n2Null or n3Null) then
    begin
      Result := n1 + n2 + n3;
      // once there is a result, then reset the NULL flag
      resultNull := False;
    end;
    PWordBool(PByte(AInMsg) + xOutputMetadata.getNullOffset(AStatus, 0))^ :=
      resultNull;
    PInteger(PByte(AInMsg) + xOutputMetadata.getOffset(AStatus, 0))^ := Result;
  finally
    xInputMetadata.release;
    xOutputMetadata.release;
  end;
end;

function TSumArgsFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  // create an instance of an external function
  Result := TSumArgsFunction.Create();
end;

  // External function TSumArgsFunction.
  TSumArgsFunction = class(IExternalFunctionImpl)
  private
    FMetadata: IRoutineMetadata;
  public
    property Metadata: IRoutineMetadata read FMetadata write FMetadata;
  public
  ...
  end;

function TSumArgsFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := TSumArgsFunction.Create();
  with Result as TSumArgsFunction do
  begin
    Metadata := AMetadata;
  end;
end;

SET TERM ^ ;

CREATE OR ALTER PACKAGE MYUDR2
AS
begin
  function SqrSmallint(AInput SMALLINT) RETURNS INTEGER;
  function SqrInteger(AInput INTEGER) RETURNS BIGINT;
  function SqrBigint(AInput BIGINT) RETURNS BIGINT;
  function SqrFloat(AInput FLOAT) RETURNS DOUBLE PRECISION;
  function SqrDouble(AInput DOUBLE PRECISION) RETURNS DOUBLE PRECISION;
end^

RECREATE PACKAGE BODY MYUDR2
AS
begin
  function SqrSmallint(AInput SMALLINT) RETURNS INTEGER
  external name 'myudr2!sqrt_func'
  engine udr;

  function SqrInteger(AInput INTEGER) RETURNS BIGINT
  external name 'myudr2!sqrt_func'
  engine udr;

  function SqrBigint(AInput BIGINT) RETURNS BIGINT
  external name 'myudr2!sqrt_func'
  engine udr;

  function SqrFloat(AInput FLOAT) RETURNS DOUBLE PRECISION
  external name 'myudr2!sqrt_func'
  engine udr;

  function SqrDouble(AInput DOUBLE PRECISION) RETURNS DOUBLE PRECISION
  external name 'myudr2!sqrt_func'
  engine udr;

end
^

SET TERM ; ^

select
  myudr2.SqrSmallint(1) as n1,
  myudr2.SqrInteger(2) as n2,
  myudr2.SqrBigint(3) as n3,
  myudr2.SqrFloat(3.1) as n4,
  myudr2.SqrDouble(3.2) as n5
from rdb$database

.......................
type
  // the structure to which the input message will be mapped
  TSqrInMsg<T> = record
    n1: T;
    n1Null: WordBool;
  end;

  // the structure to which the output message will be mapped
  TSqrOutMsg<T> = record
    result: T;
    resultNull: WordBool;
  end;

  // Factory for instantiating external function TSqrFunction
  TSqrFunctionFactory = class(IUdrFunctionFactoryImpl)
    // Called when the factory is destroyed
    procedure dispose(); override;

    { Executed each time an external function is loaded into the metadata cache.
      Used to change the format of the input and output messages.

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AMetadata External function metadata)
      @param(AInBuilder Message builder for input metadata)
      @param(AOutBuilder Message builder for output metadata)
    }
    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    { Creating a new instance of an external TSqrFunction

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AMetadata External function metadata)
      @returns(External function instance)
    }
    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;


  // External function TSqrFunction.
  TSqrFunction<TIn, TOut> = class(IExternalFunctionImpl)
  private
    function sqrExec(AIn: TIn): TOut; virtual; abstract;
  public
    type
      TInput = TSqrInMsg<TIn>;
      TOutput = TSqrOutMsg<TOut>;
      PInput = ^TInput;
      POutput = ^TOutput;
    // Called when the function instance is destroyed
    procedure dispose(); override;

    { This method is called just before execute and
      tells the kernel our requested character set to communicate within this
      method. During this call, the context uses the character set obtained from
      ExternalEngine::getCharSet.

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AName Character set name)
      @param(AName Character set name length)
    }
    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    { Executing an external function

      @param(AStatus Status vector)
      @param(AContext External function execution context)
      @param(AInMsg Pointer to input message)
      @param(AOutMsg Pointer to output message)
    }
    procedure execute(AStatus: IStatus; AContext: IExternalContext;
      AInMsg: Pointer; AOutMsg: Pointer); override;
  end;

  TSqrExecSmallint = class(TSqrFunction<Smallint, Integer>)
  public
    function sqrExec(AIn: Smallint): Integer; override;
  end;

  TSqrExecInteger = class(TSqrFunction<Integer, Int64>)
  public
    function sqrExec(AIn: Integer): Int64; override;
  end;

  TSqrExecInt64 = class(TSqrFunction<Int64, Int64>)
  public
    function sqrExec(AIn: Int64): Int64; override;
  end;

  TSqrExecFloat = class(TSqrFunction<Single, Double>)
  public
    function sqrExec(AIn: Single): Double; override;
  end;

  TSqrExecDouble = class(TSqrFunction<Double, Double>)
  public
    function sqrExec(AIn: Double): Double; override;
  end;

implementation

uses
  SysUtils, FbTypes, System.TypInfo;

{ TSqrFunctionFactory }

procedure TSqrFunctionFactory.dispose;
begin
  Destroy;
end;

function TSqrFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
var
  xInputMetadata: IMessageMetadata;
  xInputType: TFBType;
begin
  // get the type of the input argument
  xInputMetadata := AMetadata.getInputMetadata(AStatus);
  xInputType := TFBType(xInputMetadata.getType(AStatus, 0));
  xInputMetadata.release;
  // create an instance of a function depending on the type
  case xInputType of
    SQL_SHORT:
      result := TSqrExecSmallint.Create();

    SQL_LONG:
      result := TSqrExecInteger.Create();
    SQL_INT64:
      result := TSqrExecInt64.Create();

    SQL_FLOAT:
      result := TSqrExecFloat.Create();
    SQL_DOUBLE, SQL_D_FLOAT:
      result := TSqrExecDouble.Create();
  else
    result := TSqrExecInt64.Create();
  end;

end;

procedure TSqrFunctionFactory.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TSqrFunction }

procedure TSqrFunction<TIn, TOut>.dispose;
begin
  Destroy;
end;

procedure TSqrFunction<TIn, TOut>.execute(AStatus: IStatus;
  AContext: IExternalContext; AInMsg, AOutMsg: Pointer);
var
  xInput: PInput;
  xOutput: POutput;
begin
  xInput := PInput(AInMsg);
  xOutput := POutput(AOutMsg);
  xOutput.resultNull := True;
  if (not xInput.n1Null) then
  begin
    xOutput.resultNull := False;
    xOutput.result := Self.sqrExec(xInput.n1);
  end;
end;

procedure TSqrFunction<TIn, TOut>.getCharSet(AStatus: IStatus;
  AContext: IExternalContext; AName: PAnsiChar; ANameSize: Cardinal);
begin
end;


{ TSqrtExecSmallint }

function TSqrExecSmallint.sqrExec(AIn: Smallint): Integer;
begin
  Result := AIn * AIn;
end;

{ TSqrExecInteger }

function TSqrExecInteger.sqrExec(AIn: Integer): Int64;
begin
  Result := AIn * AIn;
end;

{ TSqrExecInt64 }

function TSqrExecInt64.sqrExec(AIn: Int64): Int64;
begin
  Result := AIn * AIn;
end;

{ TSqrExecFloat }

function TSqrExecFloat.sqrExec(AIn: Single): Double;
begin
  Result := AIn * AIn;
end;

{ TSqrExecDouble }

function TSqrExecDouble.sqrExec(AIn: Double): Double;
begin
  Result := AIn * AIn;
end;

.................

type
  // the structure to which the input message will be mapped
  TSumArgsInMsg = record
    n1: Integer;
    n1Null: WordBool;
    n2: Integer;
    n2Null: WordBool;
    n3: Integer;
    n3Null: WordBool;
  end;

  PSumArgsInMsg = ^TSumArgsInMsg;

  // the structure to which the output message will be mapped
  TSumArgsOutMsg = record
    result: Integer;
    resultNull: WordBool;
  end;

  PSumArgsOutMsg = ^TSumArgsOutMsg;

{ TSumArgsFunctionFactory }

procedure TSumArgsFunctionFactory.dispose;
begin
  Destroy;
end;

function TSumArgsFunctionFactory.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := TSumArgsFunction.Create();
end;

procedure TSumArgsFunctionFactory.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin
  // building a message for the input parameters
  AInBuilder.setType(AStatus, 0, Cardinal(SQL_LONG));
  AInBuilder.setLength(AStatus, 0, sizeof(Int32));
  AInBuilder.setType(AStatus, 1, Cardinal(SQL_LONG));
  AInBuilder.setLength(AStatus, 1, sizeof(Int32));
  AInBuilder.setType(AStatus, 2, Cardinal(SQL_LONG));
  AInBuilder.setLength(AStatus, 2, sizeof(Int32));
  // building a message for output parameters
  AOutBuilder.setType(AStatus, 0, Cardinal(SQL_LONG));
  AOutBuilder.setLength(AStatus, 0, sizeof(Int32));
end;

procedure TSumArgsFunction.execute(AStatus: IStatus; AContext: IExternalContext;
  AInMsg, AOutMsg: Pointer);
var
  xInput: PSumArgsInMsg;
  xOutput: PSumArgsOutMsg;
begin
  // convert pointers to input and output to typed
  xInput := PSumArgsInMsg(AInMsg);
  xOutput := PSumArgsOutMsg(AOutMsg);
  // by default, the output argument is NULL, so we set it to nullFlag
  xOutput^.resultNull := True;
  // if one of the arguments is NULL, then the result is NULL
   // otherwise, we calculate the sum of the arguments
  with xInput^ do
  begin
    if not(n1Null or n2Null or n3Null) then
    begin
      xOutput^.result := n1 + n2 + n3;
      // once there is a result, then reset the NULL flag
      xOutput^.resultNull := False;
    end;
  end;
end;

CREATE OR ALTER FUNCTION FN_SUM_ARGS (
    N1 VARCHAR(15),
    N2 VARCHAR(15),
    N3 VARCHAR(15))
RETURNS VARCHAR(15)
EXTERNAL NAME 'MyUdrSetup!sum_args'
ENGINE UDR;

select FN_SUM_ARGS('15', '21', '35') from rdb$database

unit UdrFactories;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses SysUtils, Firebird;

type

  // A simple external function factory
  TFunctionSimpleFactory<T: IExternalFunctionImpl, constructor> = class
    (IUdrFunctionFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;

  // A simple external procedure factory
  TProcedureSimpleFactory<T: IExternalProcedureImpl, constructor> = class
    (IUdrProcedureFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalProcedure; override;
  end;

  // A simple external trigger factory
  TTriggerSimpleFactory<T: IExternalTriggerImpl, constructor> = class
    (IUdrTriggerFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AFieldsBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalTrigger; override;
  end;

implementation

{ TProcedureSimpleFactory<T> }

procedure TProcedureSimpleFactory<T>.dispose;
begin
  Destroy;
end;

function TProcedureSimpleFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalProcedure;
begin
  Result := T.Create;
end;

procedure TProcedureSimpleFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;


{ TFunctionFactory<T> }

procedure TFunctionSimpleFactory<T>.dispose;
begin
  Destroy;
end;

function TFunctionSimpleFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := T.Create;
end;

procedure TFunctionSimpleFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TTriggerSimpleFactory<T> }

procedure TTriggerSimpleFactory<T>.dispose;
begin
  Destroy;
end;

function TTriggerSimpleFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalTrigger;
begin
  Result := T.Create;
end;

procedure TTriggerSimpleFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AFieldsBuilder: IMetadataBuilder);
begin

end;

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // register our function
  AUdrPlugin.registerFunction(AStatus, 'sum_args',
    TFunctionSimpleFactory<TSumArgsFunction>.Create());
  // register our procedure
  AUdrPlugin.registerProcedure(AStatus, 'gen_rows',
    TProcedureSimpleFactory<TGenRowsProcedure>.Create());
  // register our trigger
  AUdrPlugin.registerTrigger(AStatus, 'test_trigger',
    TTriggerSimpleFactory<TMyTrigger>.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

unit UdrFactories;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses SysUtils, Firebird;

type
...

  // External function with metadata
  TExternalFunction = class(IExternalFunctionImpl)
    Metadata: IRoutineMetadata;
  end;

  // External procedure with metadata
  TExternalProcedure = class(IExternalProcedureImpl)
    Metadata: IRoutineMetadata;
  end;

  // External trigger with metadata
  TExternalTrigger = class(IExternalTriggerImpl)
    Metadata: IRoutineMetadata;
  end;

unit UdrFactories;

{$IFDEF FPC}
{$MODE DELPHI}{$H+}
{$ENDIF}

interface

uses SysUtils, Firebird;

type
...

  // Factory of external functions with metadata
  TFunctionFactory<T: TExternalFunction, constructor> = class
    (IUdrFunctionFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;

  // Factory of external procedures with metadata
  TProcedureFactory<T: TExternalProcedure, constructor> = class
    (IUdrProcedureFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalProcedure; override;
  end;

  // Factory of external triggers with metadata
  TTriggerFactory<T: TExternalTrigger, constructor> = class
    (IUdrTriggerFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AFieldsBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalTrigger; override;
  end;

implementation
...

{ TFunctionFactory<T> }

procedure TFunctionFactory<T>.dispose;
begin
  Destroy;
end;

function TFunctionFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalFunction;
begin
  Result := T.Create;
  (Result as T).Metadata := AMetadata;
end;

procedure TFunctionFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TProcedureFactory<T> }

procedure TProcedureFactory<T>.dispose;
begin
  Destroy;
end;

function TProcedureFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalProcedure;
begin
  Result := T.Create;
  (Result as T).Metadata := AMetadata;
end;

procedure TProcedureFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata;
  AInBuilder, AOutBuilder: IMetadataBuilder);
begin

end;

{ TTriggerFactory<T> }

procedure TTriggerFactory<T>.dispose;
begin
  Destroy;
end;

function TTriggerFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalTrigger;
begin
  Result := T.Create;
  (Result as T).Metadata := AMetadata;
end;

procedure TTriggerFactory<T>.setup(AStatus: IStatus; AContext: IExternalContext;
  AMetadata: IRoutineMetadata; AFieldsBuilder: IMetadataBuilder);
begin

end;

create procedure split (
    txt blob sub_type text character set utf8,
    delimiter char(1) character set utf8 = ','
)
returns (
    id integer
)
external name 'myudr!split'
engine udr;

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // register our procedure
  AUdrPlugin.registerProcedure(AStatus, 'split', TProcedureSimpleFactory<TSplitProcedure>.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

...
interface

uses SysUtils, Firebird;

type

  TProcedureSimpleFactory<T: IExternalProcedureImpl, constructor> =
  class(IUdrProcedureFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalProcedure; override;
  end;

...

implementation

{ TProcedureSimpleFactory<T> }

procedure TProcedureSimpleFactory<T>.dispose;
begin
  Destroy;
end;

function TProcedureSimpleFactory<T>.newItem(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata): IExternalProcedure;
begin
  Result := T.Create;
end;

procedure TProcedureSimpleFactory<T>.setup(AStatus: IStatus;
  AContext: IExternalContext; AMetadata: IRoutineMetadata; AInBuilder,
  AOutBuilder: IMetadataBuilder);
begin

...

  TInput = record
    txt: ISC_QUAD;
    txtNull: WordBool;
    delimiter: array [0 .. 3] of AnsiChar;
    delimiterNull: WordBool;
  end;

  TInputPtr = ^TInput;

  TOutput = record
    Id: Integer;
    Null: WordBool;
  end;

  TOutputPtr = ^TOutput;

  TSplitProcedure = class(IExternalProcedureImpl)
  private
    procedure SaveBlobToStream(AStatus: IStatus; AContext: IExternalContext;
      ABlobId: ISC_QUADPtr; AStream: TStream);
    function readBlob(AStatus: IStatus; AContext: IExternalContext;
      ABlobId: ISC_QUADPtr): string;
  public
    // Called when destroying a copy of the procedure
    procedure dispose(); override;

    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    function open(AStatus: IStatus; AContext: IExternalContext; AInMsg: Pointer;
      AOutMsg: Pointer): IExternalResultSet; override;
  end;

  TSplitResultSet = class(IExternalResultSetImpl)
{$IFDEF FPC}
    OutputArray: TStringArray;
{$ELSE}
    OutputArray: TArray<string>;
{$ENDIF}
    Counter: Integer;
    Output: TOutputPtr;

    procedure dispose(); override;
    function fetch(AStatus: IStatus): Boolean; override;
  end;

function TSplitProcedure.open(AStatus: IStatus; AContext: IExternalContext;
  AInMsg, AOutMsg: Pointer): IExternalResultSet;
var
  xInput: TInputPtr;
  xText: string;
  xDelimiter: string;
begin
  xInput := AInMsg;

  Result := TSplitResultSet.Create;
  TSplitResultSet(Result).Output := AOutMsg;

  if xInput.txtNull or xInput.delimiterNull then
  begin
    with TSplitResultSet(Result) do
    begin
      // We create an empty array
      OutputArray := [];
      Counter := 1;
    end;
    Exit;
  end;

  xText := readBlob(AStatus, AContext, @xInput.txt);
  xDelimiter := TFBCharSet.CS_UTF8.GetString(TBytes(@xInput.delimiter), 0, 4);
  // automatically is not correctly determined because the lines
  // not completed by zero
  // Place the backing of byte/4
  SetLength(xDelimiter, 1);

  with TSplitResultSet(Result) do
  begin
    OutputArray := xText.Split([xDelimiter], TStringSplitOptions.ExcludeEmpty);
    Counter := 0;
  end;
end;

procedure TSplitProcedure.SaveBlobToStream(AStatus: IStatus;
  AContext: IExternalContext; ABlobId: ISC_QUADPtr; AStream: TStream);
var
  att: IAttachment;
  trx: ITransaction;
  blob: IBlob;
  buffer: array [0 .. 32767] of AnsiChar;
  l: Integer;
begin
  try
    att := AContext.getAttachment(AStatus);
    trx := AContext.getTransaction(AStatus);
    blob := att.openBlob(AStatus, trx, ABlobId, 0, nil);
    while True do
    begin
      case blob.getSegment(AStatus, SizeOf(buffer), @buffer, @l) of
        IStatus.RESULT_OK:
          AStream.WriteBuffer(buffer, l);
        IStatus.RESULT_SEGMENT:
          AStream.WriteBuffer(buffer, l);
      else
        break;
      end;
    end;
    AStream.Position := 0;
    // CLOSE method in case of success combines the IBLOB interface
    // Therefore, the subsequent call is not needed
    blob.close(AStatus);
    blob := nil;
  finally
    if Assigned(blob) then
      blob.release;
    if Assigned(trx) then
      trx.release;
    if Assigned(att) then
      att.release;
  end;
end;

function TSplitProcedure.readBlob(AStatus: IStatus; AContext: IExternalContext;
  ABlobId: ISC_QUADPtr): string;
var
{$IFDEF FPC}
  xStream: TBytesStream;
{$ELSE}
  xStream: TStringStream;
{$ENDIF}
begin
{$IFDEF FPC}
  xStream := TBytesStream.Create(nil);
{$ELSE}
  xStream := TStringStream.Create('', 65001);
{$ENDIF}
  try
    SaveBlobToStream(AStatus, AContext, ABlobId, xStream);
{$IFDEF FPC}
    Result := TEncoding.UTF8.GetString(xStream.Bytes, 0, xStream.Size);
{$ELSE}
    Result := xStream.DataString;
{$ENDIF}
  finally
    xStream.Free;
  end;
end;

procedure TSplitResultSet.dispose;
begin
  SetLength(OutputArray, 0);
  Destroy;
end;

function TSplitResultSet.fetch(AStatus: IStatus): Boolean;
var
  statusVector: array [0 .. 4] of NativeIntPtr;
begin
  if Counter <= High(OutputArray) then
  begin
    Output.Null := False;
    // Exceptions will be intercepted in any case with the ISC_Random code
    // Here we will throw out the standard for Firebird
    // error ISC_CONVERT_ERROR
    try
      Output.Id := OutputArray[Counter].ToInteger();
    except
      on e: EConvertError do
      begin

        statusVector[0] := NativeIntPtr(isc_arg_gds);
        statusVector[1] := NativeIntPtr(isc_convert_error);
        statusVector[2] := NativeIntPtr(isc_arg_string);
        statusVector[3] := NativeIntPtr(PAnsiChar('Cannot convert string to integer'));
        statusVector[4] := NativeIntPtr(isc_arg_end);

        AStatus.setErrors(@statusVector);
      end;
    end;
    inc(Counter);
    Result := True;
  end
  else
    Result := False;
end;

SELECT ids.ID
FROM SPLIT((SELECT LIST(ID) FROM MYTABLE), ',') ids

CREATE PACKAGE BlobFileUtils
AS
BEGIN
  PROCEDURE SaveBlobToFile(ABlob BLOB, AFileName VARCHAR(255) CHARACTER SET UTF8);

  FUNCTION LoadBlobFromFile(AFileName VARCHAR(255) CHARACTER SET UTF8) RETURNS BLOB;
END^

CREATE PACKAGE BODY BlobFileUtils
AS
BEGIN
  PROCEDURE SaveBlobToFile(ABlob BLOB, AFileName VARCHAR(255) CHARACTER SET UTF8)
  EXTERNAL NAME 'BlobFileUtils!SaveBlobToFile'
  ENGINE UDR;

  FUNCTION LoadBlobFromFile(AFileName VARCHAR(255) CHARACTER SET UTF8) RETURNS BLOB
  EXTERNAL NAME 'BlobFileUtils!LoadBlobFromFile'
  ENGINE UDR;
END^

function firebird_udr_plugin(AStatus: IStatus; AUnloadFlagLocal: BooleanPtr;
  AUdrPlugin: IUdrPlugin): BooleanPtr; cdecl;
begin
  // registerable
  AUdrPlugin.registerProcedure(AStatus, 'SaveBlobToFile', TSaveBlobToFileProcFactory.Create());
  AUdrPlugin.registerFunction(AStatus, 'LoadBlobFromFile', TLoadBlobFromFileFuncFactory.Create());

  theirUnloadFlag := AUnloadFlagLocal;
  Result := @myUnloadFlag;
end;

interface

uses
  Firebird, Classes, SysUtils;

type

  // Input messages of the function
  TInput = record
    filename: record
      len: Smallint;
      str: array [0 .. 1019] of AnsiChar;
    end;
    filenameNull: WordBool;
  end;
  TInputPtr = ^TInput;

  // Output function
  TOutput = record
    blobData: ISC_QUAD;
    blobDataNull: WordBool;
  end;
  TOutputPtr = ^TOutput;

  // realization features Loadblobfromfile
  TLoadBlobFromFileFunc = class(IExternalFunctionImpl)
  public
    procedure dispose(); override;

    procedure getCharSet(AStatus: IStatus; AContext: IExternalContext;
      AName: PAnsiChar; ANameSize: Cardinal); override;

    procedure execute(AStatus: IStatus; AContext: IExternalContext;
      AInMsg: Pointer; AOutMsg: Pointer); override;
  end;

  // Factory for creating a copy of the external function Loadblobfromfile
  TLoadBlobFromFileFuncFactory = class(IUdrFunctionFactoryImpl)
    procedure dispose(); override;

    procedure setup(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata; AInBuilder: IMetadataBuilder;
      AOutBuilder: IMetadataBuilder); override;

    function newItem(AStatus: IStatus; AContext: IExternalContext;
      AMetadata: IRoutineMetadata): IExternalFunction; override;
  end;

procedure TLoadBlobFromFileFunc.execute(AStatus: IStatus;
  AContext: IExternalContext; AInMsg: Pointer; AOutMsg: Pointer);
const
  MaxBufSize = 16384;
var
  xInput: TInputPtr;
  xOutput: TOutputPtr;
  xFileName: string;
  xStream: TFileStream;
  att: IAttachment;
  trx: ITransaction;
  blob: IBlob;
  buffer: array [0 .. 32767] of Byte;
  xStreamSize: Integer;
  xBufferSize: Integer;
  xReadLength: Integer;
begin
  xInput := AInMsg;
  xOutput := AOutMsg;
  if xInput.filenameNull then
  begin
    xOutput.blobDataNull := True;
    Exit;
  end;
  xOutput.blobDataNull := False;
  // We get the file name
  xFileName := TEncoding.UTF8.GetString(TBytes(@xInput.filename.str), 0,
    xInput.filename.len * 4);
  SetLength(xFileName, xInput.filename.len);
  // We read the file in the stream
  xStream := TFileStream.Create(xFileName, fmOpenRead or fmShareDenyNone);
  att := AContext.getAttachment(AStatus);
  trx := AContext.getTransaction(AStatus);
  blob := nil;
  try
    xStreamSize := xStream.Size;
    // Determine the maximum size of the buffer (segment)
    if xStreamSize > MaxBufSize then
      xBufferSize := MaxBufSize
    else
      xBufferSize := xStreamSize;
    // We create a new Blob
    blob := att.createBlob(AStatus, trx, @xOutput.blobData, 0, nil);
    // We read the contents of the stream and write it in Blob
    while xStreamSize <> 0 do
    begin
      if xStreamSize > xBufferSize then
        xReadLength := xBufferSize
      else
        xReadLength := xStreamSize;
      xStream.ReadBuffer(buffer, xReadLength);

      blob.putSegment(AStatus, xReadLength, @buffer[0]);

      Dec(xStreamSize, xReadLength);
    end;
    // Close Blob
    // CLOSE method in case of success combines the IBLOB interface
    // Therefore, the subsequent call is not needed
    blob.close(AStatus);
    blob := nil;
  finally
    if Assigned(blob) then
      blob.release;
    trx.release;
    att.release;
    xStream.Free;
  end;
end;

unit FbBlob;

interface

uses Classes, SysUtils, Firebird;

const
  MAX_SEGMENT_SIZE = $7FFF;

type
  TFbBlobHelper = class helper for IBlob
    { Loads in Blob the contents of the stream

      @param(AStatus Статус вектор)
      @param(AStream Поток)
    }
    procedure LoadFromStream(AStatus: IStatus; AStream: TStream);
    { Loads BLOB contents into the stream

      @param(AStatus Статус вектор)
      @param(AStream Поток)
    }
    procedure SaveToStream(AStatus: IStatus; AStream: TStream);
  end;

implementation

uses Math;

procedure TFbBlobHelper.LoadFromStream(AStatus: IStatus; AStream: TStream);
var
  xStreamSize: Integer;
  xReadLength: Integer;
  xBuffer: array [0 .. MAX_SEGMENT_SIZE] of Byte;
begin
  xStreamSize := AStream.Size;
  AStream.Position := 0;
  while xStreamSize <> 0 do
  begin
    xReadLength := Min(xStreamSize, MAX_SEGMENT_SIZE);
    AStream.ReadBuffer(xBuffer, xReadLength);
    Self.putSegment(AStatus, xReadLength, @xBuffer[0]);
    Dec(xStreamSize, xReadLength);
  end;
end;

procedure TFbBlobHelper.SaveToStream(AStatus: IStatus; AStream: TStream);
var
  xInfo: TFbBlobInfo;
  Buffer: array [0 .. MAX_SEGMENT_SIZE] of Byte;
  xBytesRead: Cardinal;
  xBufferSize: Cardinal;
begin
  AStream.Position := 0;
  xBufferSize := Min(SizeOf(Buffer), MAX_SEGMENT_SIZE);
  while True do
  begin
    case Self.getSegment(AStatus, xBufferSize, @Buffer[0], @xBytesRead) of
      IStatus.RESULT_OK:
        AStream.WriteBuffer(Buffer, xBytesRead);
      IStatus.RESULT_SEGMENT:
        AStream.WriteBuffer(Buffer, xBytesRead);
    else
      break;
    end;
  end;
end;

end.

procedure TLoadBlobFromFileFunc.execute(AStatus: IStatus;
  AContext: IExternalContext; AInMsg: Pointer; AOutMsg: Pointer);
var
  xInput: TInputPtr;
  xOutput: TOutputPtr;
  xFileName: string;
  xStream: TFileStream;
  att: IAttachment;
  trx: ITransaction;
  blob: IBlob;
begin
  xInput := AInMsg;
  xOutput := AOutMsg;
  if xInput.filenameNull then
  begin
    xOutput.blobDataNull := True;
    Exit;
  end;
  xOutput.blobDataNull := False;
  // We get the file name
  xFileName := TEncoding.UTF8.GetString(TBytes(@xInput.filename.str), 0,
    xInput.filename.len * 4);
  SetLength(xFileName, xInput.filename.len);
  // We read the file in the stream
  xStream := TFileStream.Create(xFileName, fmOpenRead or fmShareDenyNone);
  att := AContext.getAttachment(AStatus);
  trx := AContext.getTransaction(AStatus);
  blob := nil;
  try
    // We create a new Blob
    blob := att.createBlob(AStatus, trx, @xOutput.blobData, 0, nil);
    // We load the contents of the flow into Blob
    blob.LoadFromStream(AStatus, xStream);
    // Close Blob
    // CLOSE method in case of success combines the IBLOB interface
    // Therefore, the subsequent call is not needed
    blob.close(AStatus);
    blob := nil;
  finally
    if Assigned(blob) then
      blob.release;
    att.release;
    trx.release;
    xStream.Free;
  end;
end;