From 609837361d3a2b81e79aba466f23269faa277496 Mon Sep 17 00:00:00 2001
From: Paul Reeves <preeves@ibphoenix.com>
Date: Thu, 26 Jan 2023 16:35:00 +0100
Subject: [PATCH] Add SaveBlobToFile

---
 src/MyFirstUDRKit.cpp | 114 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 101 insertions(+), 13 deletions(-)

diff --git a/src/MyFirstUDRKit.cpp b/src/MyFirstUDRKit.cpp
index f479465..65d1e36 100644
--- a/src/MyFirstUDRKit.cpp
+++ b/src/MyFirstUDRKit.cpp
@@ -242,8 +242,95 @@ FB_UDR_EXECUTE_FUNCTION
 
 
 FB_UDR_END_FUNCTION
+//END
 
 
+
+/***
+create or alter function SaveBlobToFile (
+	afilename varchar(8191),
+	ablob BLOB
+) returns bigint
+external name 'MyFirstUDRKit!MFK_SaveBlobToFile!Save blob to file'
+engine udr;
+***/
+
+FB_UDR_BEGIN_FUNCTION(MFK_SaveBlobToFile)
+//BEGIN
+FB_UDR_MESSAGE(InMessage,
+							 (FB_CHAR(8191), afilename)
+							 (FB_BLOB, ablob)
+);
+
+FB_UDR_MESSAGE(OutMessage,
+							 (FB_BIGINT, result)
+);
+
+AutoRelease<IAttachment> att;
+AutoRelease<ITransaction> tra;
+AutoRelease<IBlob> Blob;
+
+
+FB_UDR_EXECUTE_FUNCTION
+{
+	// Test Input
+	if (in->afilenameNull != 0 || in->ablobNull != 0 )  {
+		out->resultNull = FB_TRUE;
+		out->result = 0;
+	}
+
+	/*
+	 * DOC NOTE - We do not test for existence of the file here!
+	 */
+
+	fstream File ( in->afilename.str , fstream::out | fstream::binary | fstream::app );
+	if (! File.is_open()) {
+		out->result = -2;
+		return;
+	}
+
+
+	Blob.reset(att->openBlob(status, tra, &in->ablob, 0, nullptr));
+	if (Blob == nullptr) {
+		out->result = -1;
+		return;
+	}
+
+
+	vector<char> Buffer (MaxSegmentSize, 0);
+
+	unsigned BytesRead = 0;
+
+	for (bool Eof = false; !Eof; )
+	{
+		switch (Blob->getSegment( status, MaxSegmentSize, Buffer.data(), &BytesRead))
+		{
+			case IStatus::RESULT_OK:
+			case IStatus::RESULT_SEGMENT:
+			{
+				File.write( Buffer.data(), Buffer.size() );
+				out->result += BytesRead;
+				continue;
+			}
+			default:
+			{
+				Blob->close( status ); // will close interface
+				Blob.release();
+				Eof = true;
+				break;
+			}
+		}
+	}
+
+	Buffer.clear();
+	File.close();
+
+}
+
+
+FB_UDR_END_FUNCTION
+//END
+
 /*** DDL
  create function BillDate (
 	 d    integer,
@@ -252,19 +339,20 @@ FB_UDR_END_FUNCTION
 	 external name 'my_first_udr_kit!MFK_BillDate!What does BillDate do?'
 	 engine udr;
 	 ***/
-// FB_UDR_BEGIN_FUNCTION(MFK_BillDate)
-//
-// FB_UDR_MESSAGE(InMessage,
-// 	(FB_INTEGER, d)
-// 	(FB_INTEGER, date)
-// );
-// FB_UDR_MESSAGE(OutMessage,
-// 	(FB_DATE, result)
-// 	);
-//
-//
-// FB_UDR_END_FUNCTION
-
+/*
+FB_UDR_BEGIN_FUNCTION(MFK_BillDate)
+
+FB_UDR_MESSAGE(InMessage,
+	(FB_INTEGER, d)
+	(FB_INTEGER, date)
+);
+FB_UDR_MESSAGE(OutMessage,
+	(FB_DATE, result)
+	);
+
+
+FB_UDR_END_FUNCTION
+*/