/* d4go.c   (c)Copyright Sequiter Software Inc., 1990-1994.  All rights reserved. */

#include "d4all.h"
#ifndef S4UNIX
#ifdef __TURBOC__
#pragma hdrstop
#endif
#endif

int S4FUNCTION d4go( DATA4 *data, long rec )
{
  int rc ;

#ifdef S4VBASIC
  if ( c4parm_check( data, 2, E4_D4GO ) )
    return -1 ;
#endif

  if ( data == 0 )
#ifdef S4DEBUG
    e4severe( e4parm, E4_D4GO ) ;
#else
  return -1 ;
#endif

#ifdef S4OFF_WRITE
  if ( data->code_base->error_code < 0 )
    return -1 ;
#else
  rc = d4update_record( data, 0 ) ;   /* returns -1 if code_base->error_code < 0 */
  if ( rc )
    return rc ;
#endif

#ifndef S4SINGLE
  if ( !d4lock_test( data, rec ) )  /* record not already locked */
  {
    rc = d4unlock_data( data ) ;
    if ( rc )
      return rc ;

    if ( data->code_base->read_lock )
    {
      rc = d4lock( data, rec ) ;
      if ( rc )
        return rc ;
    }
  }

#ifndef S4OPTIMIZE_OFF
  /* if bufferred old, and only record is locked, read from disk */
  if ( !data->memo_validated && data->file.do_buffer && !data->file_lock )
    if ( d4lock_test( data, rec ) )
      data->code_base->opt.force_current = 1 ;
#endif
#endif

  rc = d4go_data( data, rec ) ;

#ifndef S4SINGLE
#ifndef S4OPTIMIZE_OFF
  data->code_base->opt.force_current = 0 ;
#endif
#endif

  if ( rc )
    return rc ;

  data->bof_flag = data->eof_flag = 0 ;

#ifndef S4SINGLE
  if ( d4lock_test( data, rec ) )
  {
#endif
    memcpy( data->record_old, data->record, data->record_width ) ;
    data->rec_num_old = data->rec_num ;
    data->memo_validated = 1 ;
#ifndef S4SINGLE
  }
  else
    data->memo_validated = 0 ;
#endif

#ifndef S4OPTIMIZE_OFF
#ifndef S4DETECT_OFF
  data->code_base->mode |= 0x01 ;
#endif
#endif

  return rc ;
}

int S4FUNCTION d4go_data( DATA4 *data, long rec )
{
  unsigned len ;

  if ( data == 0 )
#ifdef S4DEBUG
    e4severe( e4parm, E4_D4GO_DATA ) ;
#else
  return -1 ;
#endif

  if( data->code_base->error_code < 0 )
    return -1 ;

  if ( rec <= 0 )
    len = 0 ;
  else
  {
    len = file4read( &data->file, d4record_position( data, rec ) ,data->record, data->record_width ) ;
    if( data->code_base->error_code < 0 )
      return -1 ;
  }

  if ( len != data->record_width )
  {
    memset( data->record, ' ', data->record_width ) ;  /* clear the partially read record to avoid corruption */
    data->rec_num = -1 ;  /* at an invalid position */
    if ( data->code_base->go_error )
      return e4( data->code_base, e4read, data->file.name ) ;
    return r4entry ;
  }
  data->rec_num = rec ;
  return 0 ;
}

int  S4FUNCTION d4go_eof( DATA4 *data )
{
  int rc ;
  long count ;

  if ( data == 0 )
#ifdef S4DEBUG
    e4severe( e4parm, E4_D4GO_EOF ) ;
#else
  return -1 ;
#endif

#ifdef S4OFF_WRITE
  if ( data->code_base->error_code < 0 )
    return -1 ;
#else
  rc = d4update_record( data, 1 ) ;   /* returns -1 if code_base->error_code < 0 */
  if ( rc )
    return rc ;
#endif

  count = d4reccount( data ) ;
  if ( count < 0 )
    return -1 ;
  data->rec_num = count + 1L ;
  data->eof_flag = 1 ;
  if ( data->rec_num == 1 )
    data->bof_flag = 1 ;
  memset( data->record, ' ', data->record_width ) ;
  return r4eof ;
}