16.20 - C Function Definition - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Programming Reference
Publication ID
B035-1147-162K
Language
English (United States)
#define SQL_TEXT Unicode_Text
#include "sqltypes_td.h"
#include <string.h>
#define buffer_size 32000

void dclobdecompress(LOB_LOCATOR*        sourceLobLoc,
                     UDT_HANDLE*         resultUDT,
                     char                sqlstate[6] )
{
   LOB_RESULT_LOCATOR resultLobLoc;
   BYTE inputBuffer[buffer_size];
   BYTE outputBuffer[buffer_size*2];
   LOB_CONTEXT_ID id;
   FNC_LobLength_t readlen, writelen;
   int trunc_err = 0;
   readlen=0;
   writelen=0;

   FNC_GetDistinctResultLob(*resultUDT,&resultLobLoc);
   FNC_LobOpen(*sourceLobLoc, &id, 0, 0);
   while( FNC_LobRead(id, inputBuffer, buffer_size, &readlen) == 0 && !trunc_err )
   {
      int i=0;
      BYTE *inputPtr = inputBuffer;
      BYTE *outputPtr = outputBuffer;
      memset(outputBuffer,0,(buffer_size*2));
      for (i=0; i<readlen; i++)
      {
         memcpy(outputPtr,inputPtr,sizeof(BYTE));
         inputPtr += sizeof(BYTE);
         outputPtr += sizeof(BYTE)*2;
      }
      trunc_err = FNC_LobAppend(resultLobLoc, outputBuffer, readlen*2, &writelen);

      /* check trunc_err and properly report an error (performed in the same way as for
      a standard UDF) */
   }
   FNC_LobClose(id);
}