/*
** Configure the file-system object according to the current values of
** the LSM_CONFIG_MMAP and LSM_CONFIG_SET_COMPRESSION options.
*/
int lsmFsConfigure(lsm_db *db){
  FileSystem *pFS = db->pFS;

  lsm_env *pEnv = pFS->pEnv;
  Page *pPg;

  assert( pFS->nOut==0 );
  assert( pFS->pWaiting==0 );

  /* Reset any compression/decompression buffers already allocated */
  lsmFree(pEnv, pFS->aIBuffer);
  lsmFree(pEnv, pFS->aOBuffer);
  pFS->nBuffer = 0;

  /* Unmap the file, if it is currently mapped */
  if( pFS->pMap ){
    lsmEnvRemap(pEnv, pFS->fdDb, -1, &pFS->pMap, &pFS->nMap);
    pFS->bUseMmap = 0;
  }

  /* Free all allocate page structures */
  pPg = pFS->pLruFirst;
  while( pPg ){
    Page *pNext = pPg->pLruNext;
    if( pPg->flags & PAGE_FREE ) lsmFree(pEnv, pPg->aData);
    lsmFree(pEnv, pPg);
    pPg = pNext;
  }

  /* Zero pointers that point to deleted page objects */
  pFS->nCacheAlloc = 0;
  pFS->pLruFirst = 0;
  pFS->pLruLast = 0;
  pFS->pFree = 0;

  /* Configure the FileSystem object */
  if( db->compress.xCompress ){
    pFS->pCompress = &db->compress;
    pFS->bUseMmap = 0;
  }else{
    pFS->pCompress = 0;
    pFS->bUseMmap = db->bMmap;

  }

  return LSM_OK;
}

/*
** Close and destroy a FileSystem object.

/*
** Configure the file-system object according to the current values of
** the LSM_CONFIG_MMAP and LSM_CONFIG_SET_COMPRESSION options.
*/
int lsmFsConfigure(lsm_db *db){
  FileSystem *pFS = db->pFS;
  if( pFS ){
    lsm_env *pEnv = pFS->pEnv;
    Page *pPg;

    assert( pFS->nOut==0 );
    assert( pFS->pWaiting==0 );

    /* Reset any compression/decompression buffers already allocated */
    lsmFree(pEnv, pFS->aIBuffer);
    lsmFree(pEnv, pFS->aOBuffer);
    pFS->nBuffer = 0;

    /* Unmap the file, if it is currently mapped */
    if( pFS->pMap ){
      lsmEnvRemap(pEnv, pFS->fdDb, -1, &pFS->pMap, &pFS->nMap);
      pFS->bUseMmap = 0;
    }

    /* Free all allocate page structures */
    pPg = pFS->pLruFirst;
    while( pPg ){
      Page *pNext = pPg->pLruNext;
      if( pPg->flags & PAGE_FREE ) lsmFree(pEnv, pPg->aData);
      lsmFree(pEnv, pPg);
      pPg = pNext;
    }

    /* Zero pointers that point to deleted page objects */
    pFS->nCacheAlloc = 0;
    pFS->pLruFirst = 0;
    pFS->pLruLast = 0;
    pFS->pFree = 0;

    /* Configure the FileSystem object */
    if( db->compress.xCompress ){
      pFS->pCompress = &db->compress;
      pFS->bUseMmap = 0;
    }else{
      pFS->pCompress = 0;
      pFS->bUseMmap = db->bMmap;
    }
  }

  return LSM_OK;
}

/*
** Close and destroy a FileSystem object.

      }
      *piVal = pDb->eSafety;
      break;
    }

    case LSM_CONFIG_MMAP: {
      int *piVal = va_arg(ap, int *);
      if( pDb->pDatabase==0 ){
        pDb->bMmap = (LSM_IS_64_BIT && *piVal);

      }
      *piVal = pDb->bMmap;
      break;
    }

    case LSM_CONFIG_USE_LOG: {
      int *piVal = va_arg(ap, int *);

      }
      *piVal = pDb->eSafety;
      break;
    }

    case LSM_CONFIG_MMAP: {
      int *piVal = va_arg(ap, int *);
      if( pDb->iReader<0 && *piVal>=0 && *piVal<=1 ){
        pDb->bMmap = *piVal;
        rc = lsmFsConfigure(pDb);
      }
      *piVal = pDb->bMmap;
      break;
    }

    case LSM_CONFIG_USE_LOG: {
      int *piVal = va_arg(ap, int *);

  return rc;
}

static int lsmPosixOsTruncate(
  lsm_file *pFile,                /* File to write to */
  lsm_i64 nSize                   /* Size to truncate file to */
){

  int rc = LSM_OK;
  int prc;                        /* Posix Return Code */
  PosixFile *p = (PosixFile *)pFile;




  prc = ftruncate(p->fd, (off_t)nSize);

  if( prc<0 ) rc = lsm_ioerr();

  return rc;
}

static int lsmPosixOsRead(
  lsm_file *pFile,                /* File to read from */

  return rc;
}

static int lsmPosixOsTruncate(
  lsm_file *pFile,                /* File to write to */
  lsm_i64 nSize                   /* Size to truncate file to */
){
  PosixFile *p = (PosixFile *)pFile;
  int rc = LSM_OK;                /* Return code */
  int prc;                        /* Posix Return Code */

  struct stat sStat;              /* Result of fstat() invocation */
  
  prc = fstat(p->fd, &sStat);
  if( prc==0 && sStat.st_size>nSize ){
    prc = ftruncate(p->fd, (off_t)nSize);
  }
  if( prc<0 ) rc = lsm_ioerr();

  return rc;
}

static int lsmPosixOsRead(
  lsm_file *pFile,                /* File to read from */

# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************




#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix lsm4
db close

# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# The focus of this file is testing the LSM library. More specifically,
# it focuses on testing the compression, compression-id and
# compression-factory functionality.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix lsm4
db close

# 2013 February 08
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# The focus of this file is testing the LSM library. 
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix lsm5
db close

#-------------------------------------------------------------------------
# When the database system is shut down (i.e. when the last connection
# disconnects), an attempt is made to truncate the database file to the
# minimum number of blocks required.
# 
# This test case checks that this process does not actually cause the
# database to grow.
# 
do_test 1.1 {
  lsm_open db test.db
  db config {mmap 0}
} {0}
do_test 1.2 {
  db write 1 one
  db write 2 two
  db close
} {}
do_test 1.3 {
  expr [file size test.db] < (64*1024)
} 1

finish_test

    always set to 0.
    <p> If it is set to true, the entire database file is memory mapped. Or, if
    it is false, data is accessed using ordinary OS file read and write
    primitives. Memory mapping the database file can significantly improve the
    performance of read operations, as database pages do not have to be copied
    from operating system buffers into user space buffers before they can be
    examined. 
    <p>This option can only be set before lsm_open() is called on the database
    connection.
    <p>The default value is 1 (true) on a 64-bit platform, and 0 otherwise.

  <dt> <a href=lsmapi.wiki#LSM_CONFIG_MULTIPLE_PROCESSES>LSM_CONFIG_MULTIPLE_PROCESSES</a>
  <dd> <p style=margin-top:0>
    This option may also be set to either 1 (true) or 0 (false).  The default
    value is 1 (true). If it is set to false, then the library assumes that all
    database clients are located within the same process (have access to the

    always set to 0.
    <p> If it is set to true, the entire database file is memory mapped. Or, if
    it is false, data is accessed using ordinary OS file read and write
    primitives. Memory mapping the database file can significantly improve the
    performance of read operations, as database pages do not have to be copied
    from operating system buffers into user space buffers before they can be
    examined. 
    <p>This option may not be set if there is a read or write transaction
    open on the database.
    <p>The default value is 1 (true) on a 64-bit platform, and 0 otherwise.

  <dt> <a href=lsmapi.wiki#LSM_CONFIG_MULTIPLE_PROCESSES>LSM_CONFIG_MULTIPLE_PROCESSES</a>
  <dd> <p style=margin-top:0>
    This option may also be set to either 1 (true) or 0 (false).  The default
    value is 1 (true). If it is set to false, then the library assumes that all
    database clients are located within the same process (have access to the