#ident "$URL: svn://elmer/devel/SVN/SDDAS/trunk/libdB/GetDbfRecord.c $ %D% SwRI"

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include "dbf.h"

/************************
 ** >FILE: GetDbfRecord.c
 ************************/

/******************************************************
 ** Function:  int GetDbfRecord(int dbf, int RecNum)
 **
 **    int dbf    handle to database structure
 **    int RecNum    record number to read
 **
 ** Description:
 **    This routine reads the RecNm record from the database associated with
 ** the database structure D.  THe RecNum is checked for a valid record
 ** number and returns an error if RecNum is not within a valid record number
 ** range.  Before reading the RecNum record, a check is made to make sure
 ** the current reocrd has not been updated, if it has been updated then the
 ** record is written to the file.
 **
 ** Return Values:
 **    * FAILURE - dbf_code set to actual error
 **    * SUCCESS - the routine completed without error
 **
 *****************
 *****************/

dbRet_t GetDbfRecord(SDDAS_INT dbf, SDDAS_INT RecNum)
{
   dbfRecord_t *D;
   int nbytes;
   off_t offset;


   if ((D = GetOldDbfHandle(dbf)) == NULL) 
      return FAILURE;

   /*
    | check for a valid record number
    */
   if (RecNum > D->NumRecs)
   {
      sprintf(msg, "'%s'", D->FileName);
      dbf_code = REC_TOO_HIGH;
      return FAILURE;
   }
   else if (RecNum < 1)
   {
      sprintf(msg, "'%s'", D->FileName);
      dbf_code = REC_TOO_LOW;
      return FAILURE;
   }

   /*
    | update the current record if needed
    */
   if (D->rStatus == Updated)
   {
      if (PutDbfRecord (dbf, D->CurRec) != SUCCESS)
      {
         return FAILURE;
      }
   }

   /*
    | position to the record to read
    */
   offset = D->HeadLen + (RecNum-1) * D->RecLen;
   if ((nbytes=lseek(D->dFile, offset, SEEK_SET)) < offset)
   {
      sprintf(msg, "'%s'", D->FileName);
      if (nbytes == -1)
         dbf_code = errno;
      else
         dbf_code = LSEEK_ERROR;
      return FAILURE;
   }

   if ((nbytes=read(D->dFile, (char *)D->CurRecord, D->RecLen)) < D->RecLen)
   {
      sprintf(msg, "'%s'", D->FileName);
      if (nbytes == -1)
         dbf_code = errno;
      else
         dbf_code = READ_ERROR;
      return FAILURE;
   }

   /*
    | update the current record number
    */
   D->CurRec = RecNum;

   dbf_msg_clr;
   dbf_code = 0;
   return SUCCESS;
}


/******************************************************
 ** Function:  int PutDbfRecord(int dbf, int RecNum)
 **
 **    int dbf    handle to database structure
 **
 ** Description:
 **    The PutDbfRecord routine writes the current record to the database
 ** file at RecNum.  THe record number is checked for a valid record number,
 ** if the RecNum number is greater than the number of records in the
 ** database, RecNum is changed to be the new last record number.  If however
 ** RecNum is less than 1 then an error is returned.  The record status is
 ** updated and if this is a new record then the header status is changed to
 ** 'Updated' so the header will be updated upon close.
 **
 ** Return Values:
 **
 *****************
 *****************/

dbRet_t PutDbfRecord(SDDAS_INT dbf, SDDAS_INT RecNum)
{ 
   dbfRecord_t *D;
   char new_rec;
   int nbytes;
   off_t offset;

   
   if ((D = GetOldDbfHandle(dbf)) == NULL) 
      return FAILURE;

   new_rec = 0;

   /*
    | check the record numbwe for a valid number
    */
   if (RecNum > D->NumRecs)
   {
      RecNum = D->NumRecs+1;
      D->NumRecs = RecNum;
      new_rec = 1;
      D->CurRecord[0][0] = ' ';
   }

   offset = D->HeadLen + (RecNum-1) * D->RecLen;
   if ((nbytes=lseek(D->dFile, offset, SEEK_SET)) < offset)
   {
      sprintf(msg, "'%s'", D->FileName);
      if (nbytes == -1)
         dbf_code = errno;
      else
         dbf_code = LSEEK_ERROR;
      return FAILURE;
   }

   if ((nbytes=write(D->dFile, (char *)D->CurRecord, D->RecLen)) < D->RecLen)
   {
      sprintf(msg, "'%s'", D->FileName);
      perror ("write");
      dbf_code = errno;
      return FAILURE;
   }

   D->rStatus = NotUpdated;

   if (new_rec)
      D->hStatus = Updated;

   D->CurRec = RecNum;

   dbf_msg_clr;
   dbf_code = 0;
   return SUCCESS;
}


/***************************************
 ** Function:  int AppendDbf(int dbf)
 **
 **    int dbf    handle to database structure
 **
 ** Description:
 **    This routine simply calls PutDbfRecord with a new last record number
 ** to append the current record in memory to the database.
 **
 ** Return Values:
 **
 **    * return value from PutDbfRecord()
 **
 *****************
 *****************/

dbRet_t AppendDbf(SDDAS_INT dbf)
{
   dbfRecord_t *D;

   if ((D = GetOldDbfHandle(dbf)) == NULL) 
      return FAILURE;

   return(PutDbfRecord(dbf, (int)(D->NumRecs+1)));
}