/*@@
   @file      CheckpointRecovery.c
   @date      Jun 04 1999
   @author    Thomas Radke
   @desc
              Utility routines for checkpointing/recovery and the filereader
              The actual work is done by the IO thorns.
   @enddesc
   @version   $Id$
 @@*/

#include "cctk.h"
#include "cctk_Parameters.h"
#include "cctk_FortranString.h"
#include "util_Table.h"

#include "ioGH.h"
#include "ioutil_CheckpointRecovery.h"


#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef HAVE_DIRENT_H
#include <dirent.h>
#endif

#include "util_String.h"

static const char *rcsid = "$Header$";
CCTK_FILEVERSION(CactusBase_IOUtil_CheckpointRecovery_c)


/********************************************************************
 ********************    External Routines   ************************
 ********************************************************************/
void IOUtil_RecoverGH (cGH *GH);
void IOUtil_RecoverIDFromDatafiles (cGH *GH);
void CCTK_FCALL CCTK_FNAME (IOUtil_RecoverVarsFromDatafiles)
                           (int *result, cGH **GH, TWO_FORTSTRING_ARG);


/********************************************************************
 ********************    Static Variables   *************************
 ********************************************************************/
/* table to store registered recovery functions */
static int recover_fn_table = -1;
static int checkpoint_file_exists = 0;


/********************************************************************
 ********************    Internal Typedefs   ************************
 ********************************************************************/
typedef struct
{
  char *basename;
  int iteration;
} filelist_t;

typedef int (*recover_fn_t) (cGH *GH, const char *basefilename,int called_from);

/********************************************************************
 ********************    Internal Routines   ************************
 ********************************************************************/
static char *EncodeString (const char *string);
static char *DecodeString (const char *string);
static int OctalDigitToInt (const char digit);
static void SetInputFlag (int vindex, const char *optstring, void *arg);
#ifdef HAVE_DIRENT_H
static int CompareFiles (const void *a, const void *b);
#endif


/************************************************************************
 *
 *  Registration functions for Restoring from IO Files
 *
 ************************************************************************/

 /*@@
   @routine    IOUtil_RegisterRecover
   @date       Monday 21 June 1999
   @author     Gabrielle Allen
   @desc
               Registers a new recovery method
   @enddesc
   @calls      Util_GetHandle
               Util_NewHandle

   @var        name
   @vdesc      The name of the function for recovery
   @vtype      const char *
   @vio        in
   @endvar
   @var        recover_fn
   @vdesc      the recovery function to register
   @vtype      recover_fn_t
   @vio        in
   @endvar

   @returntype int
   @returndesc
               0  for success, or<BR>
               -1 method with this name already registered
   @endreturndesc
@@*/
int IOUtil_RegisterRecover (const char *name, recover_fn_t recover_fn)
{
  int retval;


  /* create the function pointer table on the first time through */
  if (recover_fn_table < 0)
  {
    recover_fn_table = Util_TableCreate (UTIL_TABLE_FLAGS_DEFAULT);
  }

  /* check that the method hasn't already been registered */
  retval = Util_TableQueryValueInfo (recover_fn_table, NULL,NULL,name) ? -1 : 0;
  if (! retval)
  {
    Util_TableSetFnPointer (recover_fn_table, (CCTK_FPOINTER) recover_fn, name);
  }

  return (retval);
}


 /*@@
   @routine    IOUtil_AssembleFilename
   @date       30 June 2004
   @author     Thomas Radke
   @desc
               This routine assembles the full basename for checkpoint/recovery
               and filereader files, paying attention to the different types:

                 * it returns the full filename (directory+filename)
                 * for cp files it prepends the iteration number as "it_%d"
                 * for chunked files it prepends the file number as "file_%d"

               This routine replaces the old routine IOUtil_PrepareFilename()
               which should not be used anymore.
   @enddesc

   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      const cGH *
   @vio        in
   @endvar
   @var        basefilename
   @vdesc      basename of the file
   @vtype      const char *
   @vio        in
   @endvar
   @var        postfix
   @vdesc      optional postfix to append to the basename
               (eg. ".tmp" for temporary files, or "" for no postfix)
   @vtype      const char *
   @vio        in
   @var        extension
   @vdesc      file extension to append to the basefilename
               (should be given with the dot, eg. as ".h5")
   @vtype      const char *
   @vio        in
   @endvar
   @var        called_from
   @vdesc      indicates the caller function:
                 * either Filereader (FILEREADER_DATA)
                 * or IOUtil_RecoverGH() (CP_RECOVER_DATA)
   @vtype      int
   @vio        in
   @endvar
   @var        file_ioproc
   @vdesc      the IO processor number (for chunked files)
   @vtype      int
   @vio        in
   @endvar
   @var        file_unchunked
   @vdesc      flag to indicate whether file mode is unchunked or not
   @vtype      int
   @vio        in
   @endvar

   @returntype char *
   @returndesc
               the filename (must be freed after use)
   @endreturndesc
@@*/
char *IOUtil_AssembleFilename (const cGH *GH,
                               const char *basefilename,
                               const char *postfix,
                               const char *extension,
                               int called_from,
                               int file_ioproc,
                               int file_unchunked)
{
  DECLARE_CCTK_PARAMETERS
  size_t filenamelen;
  char *filename;
  const char *dir, *basename;
  char iteration_postfix[32], filenumber_postfix[32];


  /* get the right parameters */
  dir = basename = NULL;
  switch (called_from)
  {
    case CP_INITIAL_DATA:
      dir = checkpoint_dir;
      basename = checkpoint_ID_file;
      if (CCTK_CreateDirectory(0755, checkpoint_dir) < 0)
        CCTK_VWarn(0, __LINE__, __FILE__, CCTK_THORNSTRING,
                   "Checkpoint directory %s could not be created",
                   checkpoint_dir);
      break;

    case CP_EVOLUTION_DATA:
      dir = checkpoint_dir;
      basename = checkpoint_file;
      if (CCTK_CreateDirectory(0755, checkpoint_dir) < 0)
        CCTK_VWarn(0, __LINE__, __FILE__, CCTK_THORNSTRING,
                   "Checkpoint directory %s could not be created",
                   checkpoint_dir);
      break;

    case CP_RECOVER_DATA:
    case CP_RECOVER_PARAMETERS:
      dir = recover_dir;
      basename = basefilename ? basefilename : recover_file;
      break;
    case FILEREADER_DATA:
      dir = filereader_ID_dir;
      basename = basefilename ? basefilename : recover_file;
      break;

    default:
      CCTK_VWarn (0, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "IOUtil_AssembleFilename: unknown calling mode %d",
                  called_from);
      break;
  }

  /* if checkpoint filename, merge in the iteration number
     and for chunked files also the file number */
  iteration_postfix[0] = 0;
  if (called_from == CP_INITIAL_DATA || called_from == CP_EVOLUTION_DATA)
  {
    Util_snprintf (iteration_postfix, sizeof (iteration_postfix), ".it_%d",
                   (int) GH->cctk_iteration);
  }

  /* If not one unchunked file give a file number */
  filenumber_postfix[0] = 0;
  if (! file_unchunked)
  {
    Util_snprintf (filenumber_postfix, sizeof (filenumber_postfix), ".file_%d",
                   file_ioproc);
  }

  if (! (dir && basename && postfix && extension))
    CCTK_VWarn (0, __LINE__, __FILE__,"IOUtil", "Directory, basename, postfix or extension error");
  filenamelen = strlen (dir) + strlen (basename) + strlen (postfix) +
                strlen (iteration_postfix) + strlen (filenumber_postfix) +
                strlen (extension) + 2;
  filename = malloc (filenamelen);
  if (! (filename))
    CCTK_VWarn (0, __LINE__, __FILE__,"IOUtil", "File name error");
  Util_snprintf (filename, filenamelen, "%s/%s%s%s%s%s", dir, basename, postfix,
                 iteration_postfix, filenumber_postfix, extension);

  return (filename);
}


 /*@@
   @routine    IOUtil_RecoverFromFile
   @date       Jun 14 1999
   @author     Thomas Radke
   @desc
               Recover from a given file.
               This routine loops through all XXX_RecoverGH routines
               registered by IO thorns.
   @enddesc
   @calls      Util_GetHandledData
               <registered RecoverGH routines>

   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      cGH *
   @vio        in
   @endvar
   @var        basefilename
   @vdesc      basefilename of the file(s) to recover from
   @vtype      const char *
   @vio        in
   @endvar
   @var        called_from
   @vdesc      indicates the caller function:
                 * either Filereader (FILEREADER_DATA)
                 * or IOUtil_RecoverGH() (CP_RECOVER_DATA)
   @vtype      int
   @vio        in
   @endvar
@@*/
static int IOUtil_RecoverFromFile (cGH *GH,
                                   const char *basefilename,
                                   int called_from)
{
  int keylen, ihandle, retval;
  char *key;
  CCTK_FPOINTER func;
  recover_fn_t recover_fn;


  if (Util_TableQueryNKeys (recover_fn_table) <= 0)
  {
    CCTK_WARN (1, "IOUtil_RecoverFromFile: No recovery routines "
                  "were registered");
    return (-1);
  }

  keylen = Util_TableQueryMaxKeyLength (recover_fn_table) + 1;
  key = malloc (keylen);

  for (ihandle = Util_TableItCreate (recover_fn_table), retval = -1;
       Util_TableItQueryIsNonNull (ihandle) > 0 && retval < 0;
       Util_TableItAdvance (ihandle))
  {
    Util_TableItQueryKeyValueInfo (ihandle, keylen, key, NULL, NULL);
    Util_TableGetFnPointer (recover_fn_table, &func, key);
    if (func)
    {
      recover_fn = (recover_fn_t) func;
      retval = recover_fn (GH, basefilename, called_from);
    }
  }
  free (key);
  Util_TableItDestroy (ihandle);

  return (retval);
}


 /*@@
   @routine    IOUtil_RecoverGH
   @date       Jun 14 1999
   @author     Thomas Radke
   @desc
               The rfr-registered recovery routine.
               Just calls IOUtil_RecoverFromFile()
               with called_from == CP_RECOVER_DATA.
   @enddesc
   @calls      IOUtil_RecoverFromFile

   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      cGH *
   @vio        in
   @endvar
@@*/
void IOUtil_RecoverGH (cGH *GH)
{
  if (checkpoint_file_exists)
  {
    /* stop if recovery failed */
    if (IOUtil_RecoverFromFile (GH, NULL, CP_RECOVER_DATA) < 0)
    {
      CCTK_WARN (0, "Failed to restart from recovery !");
    }
  }
}


 /*@@
   @routine    IOUtil_RecoverVarsFromDatafiles
   @date       Wed Apr 19 2000
   @author     Thomas Radke
   @desc
               IOUtil's function interface to recover variables from data files.
               Any thorn can call this routine with a list of datafile names
               and a list of variables to read in from these files. <BR>

               It just calls IOUtil_RecoverFromFile() with
               called_from == FILEREADER_DATA for each data file
               from the given file list.
   @enddesc

   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      cGH *
   @vio        in
   @endvar
   @var        in_files
   @vdesc      list of filenames to process (separated by spaces)
   @vtype      const char *
   @vio        in
   @endvar
   @var        in_vars
   @vdesc      list of variable fullnames to read in from the files
   @vtype      const char *
   @vio        in
   @endvar

   @returntype int
   @returndesc
               total number of recovered variables
   @endreturndesc
@@*/
int IOUtil_RecoverVarsFromDatafiles (cGH *GH,
                                     const char *in_files,
                                     const char *in_vars)
{
  int retval, num_recovered_vars;
  ioGH *myGH;
  char *basefilename, *delim, delim_char;
  DECLARE_CCTK_PARAMETERS


  myGH = CCTK_GHExtension (GH, "IO");
  if (myGH == NULL)
  {
    CCTK_WARN (0, "invalid cctkGH pointer passed into "
               "IOUtil_RecoverVarsFromDatafiles()");
  }

  if (CCTK_NumVars () > 0)
  {
    void *calldata[2];
    myGH->do_inVars = calloc (CCTK_NumVars (), sizeof (CCTK_INT));
    myGH->alias = calloc (CCTK_NumVars (), sizeof (char *));
    calldata[0] = myGH->do_inVars;
    calldata[1] = myGH->alias;
    if (CCTK_TraverseString (in_vars, SetInputFlag, calldata,
                             CCTK_GROUP_OR_VAR) < 0)
    {
      CCTK_WARN (myGH->stop_on_parse_errors ? 0 : 1,
                 "error while parsing parameter 'IO::filereader_ID_vars'");
    }
  }
  else
  {
    myGH->do_inVars = NULL;
    myGH->alias = NULL;
  }

  num_recovered_vars = 0;

  /* duplicate the filename list and parse it */
  basefilename = strdup (in_files);
  while (basefilename && *basefilename)
  {
    /* skip leading spaces */
    while (isspace ((int) *basefilename))
    {
      basefilename++;
    }
    if (! *basefilename)
    {
      break;
    }

    /* find delimiter for current filename and cut there */
    for (delim = basefilename + 1; ! isspace ((int) *delim) && *delim; delim++);
    delim_char = *delim;
    *delim = 0;

    if (! CCTK_Equals (verbose, "none"))
    {
      CCTK_VInfo (CCTK_THORNSTRING, "Reading variables from file with base name '%s'",
                  basefilename);
    }

    retval = IOUtil_RecoverFromFile (GH, basefilename, FILEREADER_DATA);
    if (retval >= 0)
    {
      num_recovered_vars += retval;
    }
    else
    {
      CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "Failed to read variables from data file with base name '%s'", basefilename);
    }

    *delim = delim_char;
    basefilename = delim;
  }

  if (basefilename)
  {
    free (basefilename - strlen (in_files));
  }

  if (myGH->do_inVars)
  {
    free (myGH->do_inVars);
    myGH->do_inVars = NULL;
  }

  if (myGH->alias)
  {
    const int numVars = CCTK_NumVars ();
    for (int i = 0; i < numVars; i++)
    {
      if (myGH->alias[i])
        free ((void*)myGH->alias[i]);
    }
    free (myGH->alias);
    myGH->alias = NULL;
  }

  return (num_recovered_vars);
}

void CCTK_FCALL CCTK_FNAME (IOUtil_RecoverVarsFromDatafiles)
                           (int *result, cGH **GH, TWO_FORTSTRING_ARG)
{
  TWO_FORTSTRING_CREATE (in_files, in_vars)
  *result = IOUtil_RecoverVarsFromDatafiles (*GH, in_files, in_vars);
  free (in_files);
  free (in_vars);
}


 /*@@
   @routine    IOUtil_RecoverIDFromDatafiles
   @date       Wed Apr 19 2000
   @author     Thomas Radke
   @desc
               The rfr-registered initial data recovery routine.
               Just calls IOUtil's generic routine
               IOUtil_RecoverVarsFromDatafiles() with the filereader_ID_XXX
               parameters.
   @enddesc
   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      cGH *
   @vio        in
   @endvar
@@*/
void IOUtil_RecoverIDFromDatafiles (cGH *GH)
{
  ioGH *myGH;
  DECLARE_CCTK_PARAMETERS


  myGH = CCTK_GHExtension (GH, "IO");
  myGH->stop_on_parse_errors = strict_io_parameter_check;
  IOUtil_RecoverVarsFromDatafiles (GH, filereader_ID_files, filereader_ID_vars);
  myGH->stop_on_parse_errors = 0;
}


 /*@@
   @routine    IOUtil_RecoverParameters
   @date       Apr 22 2000
   @author     Thomas Radke
   @desc
               The generic parameter recovery routine.
               It is called by the IO thorns' parameter recovery routines
               scheduled at CCTK_RECOVER_PARAMETERS, and simply calls
               the given callback routine with its arguments
               plus a checkpoint filename.
   @enddesc

   @var        recover_fn
   @vdesc      callback function for recovery of parameters
               from a given checkpoint file
   @vtype      int (*) (cGH *, const char *, int)
   @vio        in
   @endvar
   @var        fileExtension
   @vdesc      extension of valid checkpoint files for given callback
   @vtype      const char *
   @vio        in
   @endvar
   @var        fileType
   @vdesc      string to describe the type of checkpoint file
               (used for warning/info messages)
   @vtype      const char *
   @vio        in
   @endvar

   @returntype int
   @returndesc
                0 if in "autoprobe" mode and no cp files were found, or<BR>
               +1 if parameter recovery was successful for some cp file,<BR>
               -1 if in "auto" mode and no checkpoint files were found,
                  or if parameter recovery failed for some cp file,<BR>
               -2 if in "auto*" mode and recovery dir doesn't exist
   @endreturndesc
@@*/
int IOUtil_RecoverParameters (int (*recover_fn) (cGH *GH,
                                                 const char *basefilename,
                                                 int called_from),
                              const char *fileExtension,
                              const char *fileType)
{
  int retval;
#ifdef HAVE_DIRENT_H
  int len, recover_file_len;
  unsigned int num_files;
  const char *p, *q;
  DIR *dir;
  struct dirent *file;
  filelist_t *filelist, *tmp;
#endif
  DECLARE_CCTK_PARAMETERS


  if (CCTK_Equals (recover, "auto") || CCTK_Equals (recover, "autoprobe"))
  {
#ifdef HAVE_DIRENT_H
    if (CCTK_Equals (verbose, "full"))
    {
      CCTK_VInfo (CCTK_THORNSTRING, "Searching for %s checkpoint files "
                  "with basefilename '%s' in directory '%s'",
                  fileType, recover_file, recover_dir);
    }

    dir = opendir (recover_dir);
    if (! dir)
    {
      /* The recovery directory does not exist */
      if (CCTK_Equals (recover, "autoprobe"))
      {
        /* This is harmless when "autoprobe" is used */
        CCTK_VInfo (CCTK_THORNSTRING,
                    "Recovery directory '%s' doesn't exist", recover_dir);
        return 0;
      }
      else
      {
        /* This is an error when "auto" is used */
        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                    "Recovery directory '%s' doesn't exist", recover_dir);
        return -2;
      }
    }

    /* get the list of potential recovery files */
    recover_file_len = strlen (recover_file);
    num_files = 0;
    filelist = NULL;

    while ((file = readdir (dir)) != NULL)
    {
      /* first check the file prefix */
      if (strncmp (file->d_name, recover_file, recover_file_len) ||
          strncmp (file->d_name + recover_file_len, ".it_", 4))
      {
        continue;
      }

      /* now check if there is an iteration number following the file prefix */
      for (p = file->d_name + recover_file_len + 4; *p && *p != '.'; p++)
      {
        if (! isdigit ((int) *p))
        {
          break;
        }
      }

      /* check for a '.file_<processor>' suffix for chunked output */
      q = p;
      if (! strncmp (q, ".file_", 6))
      {
        /* read past the <processor> number */
        for (q = q + 6; *q && *q != '.'; q++)
        {
          if (! isdigit ((int) *q))
          {
            break;
          }
        }
      }

      /* finally check the file extension suffix */
      if (*q != '.' || strcmp (q, fileExtension))
      {
        continue;
      }

      /* found a recovery file by that basename */
      if (num_files == 0)
      {
        tmp = malloc (sizeof (filelist_t));
      }
      else
      {
        tmp = realloc (filelist, (num_files+1) * sizeof (filelist_t));
      }
      if (tmp == NULL)
      {
        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                    "Failed to allocate memory for file list");
        continue;
      }
      filelist = tmp;
      filelist[num_files].basename = strdup (file->d_name);
      /* cut the filename after the iteration number field */
      len = p - file->d_name;
      filelist[num_files].basename[len] = 0;
      filelist[num_files].iteration = atoi (file->d_name + recover_file_len+4);

      num_files++;
    }
    closedir (dir);

    retval = CCTK_Equals (recover, "auto") ? -1 : 0;
    if (num_files)
    {
      /* sort the list according to their iteration numbers */
      qsort (filelist, num_files, sizeof (filelist_t), CompareFiles);

      /* loop over all recovery files found and call the callback routine;
         skip all following files after the first successful recovery (when
         recover_fn() returned a positive value) */
      while (num_files--)
      {
        if (retval <= 0)
        {
          retval = recover_fn (NULL, filelist[num_files].basename,
                               CP_RECOVER_PARAMETERS);
        }
        free (filelist[num_files].basename);
      }
      free (filelist);
    }
    else
    {
      CCTK_VWarn (retval ? 1 : 3, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "No %s checkpoint files with basefilename '%s' found in "
                  "recovery directory '%s'",
                  fileType, recover_file, recover_dir);
    }
#else
    fileExtension = fileExtension;

    /* No opendir(3) ??? It's probably a Windows box, so just give up ! */
    CCTK_WARN (0, "You cannot use 'IO::recover = \"auto*\"' on "
               "this architecture because it doesn't provide opendir(3) to "
               "automatically look for checkpoint files.\n"
               "Please use 'IO::recover = \"manual\"' instead !");
    retval = -1;
#endif
  }
  else
  {
    /* just call the recovery routine */
    retval = (*recover_fn) (NULL, recover_file, CP_RECOVER_PARAMETERS);
  }

  if (retval < 0)
  {
    CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Could not recover parameters from %s checkpoint file(s) "
                "with basefilename '%s' in recovery directory '%s'",
                fileType, recover_file, recover_dir);
  }

  /* remember parameter recovery status for later evaluation in
     IOUtil_RecoverGH() */
  checkpoint_file_exists = retval > 0;

  return (retval);
}


 /*@@
   @routine    IOUtil_GetAllParameters
   @date       Mon Apr 10 2000
   @author     Thomas Radke
   @desc
               Collect all parameters of active implementations
               into a single string which can then be dumped as an attribute.

               Each "<parameter> = <value>" pair in the resulting string
               is separated by a newline character from the next pair.
               The "<value>" substring is encoded such that non-printable
               characters are contained as escape sequences, and a single
               '\' character is escaped by another '\' character.
   @enddesc

   @var        GH
   @vdesc      pointer to CCTK grid hierarchy
   @vtype      const cGH *
   @vio        in
   @endvar
   @var        all
   @vdesc      flag indicating whether to save all parameters or just the ones
               which have been set before
   @vtype      int
   @vio        in
   @endvar

   @returntype char *
   @returndesc the allocated string or NULL
   @endreturndesc
@@*/
char *IOUtil_GetAllParameters (const cGH *GH, int all)
{
  int i, first, add_len, current_len, max_len;
  char *param, *value, *encoded_value, *tmp, *retval;
  const char *thorn;
  const cParamData *pdata;
  DECLARE_CCTK_PARAMETERS


  /* avoid compiler warning about unused parameter */
  GH = GH;

  /* preallocate buffer for parameters, to prevent too many subsequent reallocs
     (causing unnecessary memory fragmentation) */
  max_len = 1024*1024;
  retval = malloc(max_len);
  if (! retval)
  {
    CCTK_VWarn (0, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Failed to allocate buffer of %d bytes", max_len);
  }
  current_len = 0;

  /* loop over all thorns */
  for (i = CCTK_NumCompiledThorns () - 1; i >= 0; i--)
  {
    thorn = CCTK_CompiledThorn (i);

    /* skip all inactive thorns */
    if (! CCTK_IsThornActive (thorn))
    {
      continue;
    }

    /* now walk through all parameters of given thorn */
    first = 1;
    while (CCTK_ParameterWalk (first, thorn, &param, &pdata) == 0)
    {
      first = 0;

      /* if 'all' is false get only parameters which have been set */
      if (all || pdata->n_set > 0)
      {
        value = CCTK_ParameterValString (pdata->name, pdata->thorn);
        if (value == NULL)
        {
          CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                      "Couldn't get value for parameter '%s'", param);
        }
        else
        {
          encoded_value = EncodeString (value);
          add_len = strlen (param) + strlen (encoded_value) + 5;
          if (current_len + add_len >= max_len)
          {
            /* double new buffer length until buffer is large enough */
            while (current_len + add_len >= max_len)
            {
              max_len *= 2;
            }
            tmp = realloc (retval, max_len);
            if (! tmp)
            {
              CCTK_VWarn (0, __LINE__, __FILE__, CCTK_THORNSTRING,
                          "Failed to allocate buffer of %d bytes", max_len);
            }
            retval = tmp;
          }

          sprintf (retval + current_len, "%s = %s\n", param, encoded_value);
          current_len += add_len - 1;

          free (encoded_value);
          free (value);
        }
      }

      free (param);

    } /* end of loop walking over all parameters of given thorn */
  } /* end of looping over all thorns */

  return (retval);
}


 /*@@
   @routine    IOUtil_SetAllParameters
   @date       Mon Apr 10 2000
   @author     Thomas Radke
   @desc
               Parse the given string for parameters
               and call CCTK_SetParameter() for each.

               The input string is expected to follow the format of
               IOUtil_GetAllParameters() (see above) where each
               "<parameter> = <value>" pair is separated by a newline character
               from the next pair.
               The "<value>" substring is encoded such that non-printable
               characters are contained as escape sequences, and a single
               '\' character is escaped by another '\' character. This
               encoding is undone before setting the a value of a parameter.
   @enddesc

   @var        parameters
   @vdesc      the parameter string
   @vtype      const char *
   @vio        in
   @endvar
@@*/
void IOUtil_SetAllParameters (const char *parameters)
{
  char *tmp, *nextparam, *avalue, *decoded_value, *param;
  char oldchar;
  char *name, *thorn_impl, *parameter_string, *free_me;
  const char *thorn;
  const cParamData *paramdata;
  int ierr, steered_non_steerable;
  DECLARE_CCTK_PARAMETERS


  parameter_string = free_me = strdup (parameters);
  steered_non_steerable = 0;
  while (*parameter_string)
  {
    /* find the end of the current "<parameter> = <value>" pair substring */
    nextparam = parameter_string;
    while (*nextparam != '\n' && *nextparam)
    {
      nextparam++;
    }
    oldchar = *nextparam;
    *nextparam = 0;

    /* find the end of "<parameter>" */
    tmp = parameter_string;
    while (*tmp != ' ')
    {
      tmp++;
    }
    *tmp = 0;

    param = parameter_string;
    /* skip the " = " delimiter to get to "<value>" */
    avalue = tmp + 3;

    name = thorn_impl = NULL;
    if (Util_SplitString (&thorn_impl, &name, param, "::") == 0)
    {
      /* find out the implementing thorn of the parameter given */
      thorn = CCTK_ActivatingThorn (thorn_impl);
      if (! thorn)
      {
        thorn = thorn_impl;
      }

      /* set parameter only if it belongs to an active implementation
         and is not an accumulator parameter */
      if (CCTK_IsThornActive (thorn))
      {
        paramdata = CCTK_ParameterData (name, thorn);
        if (paramdata && ! paramdata->accumulator_expression)
        {
          decoded_value = DecodeString (avalue);
          ierr = CCTK_ParameterSet (name, thorn, decoded_value);
          if (ierr == -10)
          {
            steered_non_steerable = 1;
          }
          else if (ierr < 0)
          {
            CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                        "Couldn't set parameter '%s' to '%s'",
                        param, decoded_value);
          }
          free (decoded_value);
        }
      }
      else if (CCTK_Equals (verbose, "full"))
      {
        CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                    "Ignoring inactive parameter '%s' for recovery", param);
      }

      if (name)
      {
        free (name);
      }
      if (thorn_impl)
      {
        free (thorn_impl);
      }
    }

    *nextparam = oldchar;
    parameter_string = nextparam;
    if (*parameter_string == '\n')
    {
      parameter_string++;
    }
  }

  free (free_me);

  if (steered_non_steerable)
  {
    CCTK_ERROR ("Attempted to steer non steerable parameters.");
  }
}



/********************************************************************
 ********************    Internal Routines   ************************
 ********************************************************************/
/* encodes a C string with all the non-printable characters converted
   into a 4-char-long escape sequence representation "\xxx" and
   the single '\' character converted into "\\" */
static char *EncodeString (const char *string)
{
  size_t i, len = strlen (string);
  char *p, *retval;


  p = retval = malloc (4*len + 1);
  if (! retval)
  {
    CCTK_WARN (0, "Out of memory !");
  }

  for (i = 0; i < len; i++)
  {
    if (! isprint (string[i]))
    {
      sprintf (p, "\\%.03o", (unsigned char)string[i]);
      p += 4;
    }
    else
    {
      *p++ = string[i];
      if (string[i] == '\\')
      {
        *p++ = string[i];
      }
    }
  }
  *p = 0;

  return (retval);
}


/* decodes a string encoded by EncodeString() back into a C string */
static char *DecodeString (const char *string)
{
  size_t i, len = strlen (string);
  char *p, *retval;
  int o1, o2, o3;


  p = retval = malloc (len + 1);
  if (! retval)
  {
    CCTK_WARN (0, "Out of memory !");
  }

  for (i = 0; i < len; i++)
  {
    if (string[i] != '\\')
    {
      *p++ = string[i];
    }
    else
    {
      if (i+1 >= len) goto bail_out;
      if (string[i+1] == '\\')
      {
        *p++ = '\\'; i++;
      }
      else
      {
        if (i+3 >= len) goto bail_out;
        o1 = OctalDigitToInt (string[i+1]);
        o2 = OctalDigitToInt (string[i+2]);
        o3 = OctalDigitToInt (string[i+3]);
        if (o1 < 0 || o2 < 0 || o3 < 0) goto bail_out;
        *p++ = (char) (8*8*o1 + 8*o2 + o3);
        i += 3;
      }
    }
  }
  *p = 0;

  return (retval);

 bail_out:
  free (retval);
  CCTK_WARN (1, "Malformed string");
  return NULL;
}


/* callback for CCTK_TraverseString() to set the input flag
   for the given variable */
static void SetInputFlag (int vindex, const char *optstring, void *calldata)
{
  int table, iterator;
  char key[128];
  CCTK_INT type, nelems;
  void **flags = (void**)calldata;
  CCTK_INT *do_inVars = (CCTK_INT *) flags[0];
  const char **alias = (const char **) flags[1];


  /* default -1 is to read the last iteration number from the file */
  do_inVars[vindex] = -1;

  /* default is NULL to use CCTK_FullName() */
  alias[vindex] = NULL;

  if (optstring)
  {
    table = Util_TableCreateFromString (optstring);
    if (table >= 0)
    {
      if (Util_TableQueryValueInfo (table, &type, &nelems, "cctk_iteration") >0)
      {
        if (type == CCTK_VARIABLE_INT && nelems == 1)
        {
          Util_TableGetInt (table, &do_inVars[vindex], "cctk_iteration");

          /* if a specific iteration number was given then increment it
             to keep 0 as disabling value */
          if (do_inVars[vindex] >= 0)
          {
            do_inVars[vindex]++;
          }
        }
        else
        {
          CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                      "Invalid value for option 'cctk_iteration' in option "
                      "string '%s' (must be an integer)", optstring);
          CCTK_WARN (1, "Option will be ignored by file reader routines");
        }
        Util_TableDeleteKey (table, "cctk_iteration");
      }

      if (Util_TableQueryValueInfo (table, &type, &nelems, "alias") >0)
      {
        if (type == CCTK_VARIABLE_CHAR)
        {
          char *buf = malloc(nelems+1);
          if (! (buf))
          {
            CCTK_VError (__LINE__, __FILE__,"IOUtil",
                         "Could not allocate %d bytes", nelems+1);
          }
          int len = Util_TableGetString (table, nelems+1, buf, "alias");
          if (len != nelems)
          {
            CCTK_VError (__LINE__, __FILE__,"IOUtil",
                         "Unexpected length %d of 'alias' option value in '%s'. Expected length %d.",
                         len, optstring, nelems);
          }

          alias[vindex] = buf;
        }
        else
        {
          CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                      "Invalid value for option 'alias' in option "
                      "string '%s' (must be a string)", optstring);
          CCTK_WARN (1, "Option will be ignored by file reader routines");
        }
        Util_TableDeleteKey (table, "alias");
      }

      /* warn about other options */
      for (iterator = Util_TableItCreate (table);
           Util_TableItQueryIsNonNull (iterator) > 0 &&
           Util_TableItQueryKeyValueInfo (iterator, sizeof (key), key, 0, 0) >0;
           Util_TableItAdvance (iterator))
      {
        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                    "Found option with unrecognized key '%s' in option string "
                    "'%s'", key, optstring);
        CCTK_WARN (1, "Option will be ignored by file reader routines");
      }
      Util_TableItDestroy (iterator);

      Util_TableDestroy (table);
    }
    else
    {
      CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "Couldn't parse option string '%s'", optstring);
      CCTK_WARN (1, "Option will be ignored by file reader routines");
    }
  }
}


/* Convert an octal digit to an integer.  Return -1 if this is not an
   octal digit.  Note that this routine does not assume ASCII encoding
   (and thus cannot calculate digit-'0'), and does not use
   non-standard library function such as isoctal.  */
static int OctalDigitToInt (const char digit)
{
  switch (digit)
  {
    case '0': return 0;
    case '1': return 1;
    case '2': return 2;
    case '3': return 3;
    case '4': return 4;
    case '5': return 5;
    case '6': return 6;
    case '7': return 7;
  }
  return -1;
}


#ifdef HAVE_DIRENT_H
/* callback for qsort() to sort the list of recovery files found */
static int CompareFiles (const void *a, const void *b)
{
  return (((const filelist_t *) a)->iteration -
          ((const filelist_t *) b)->iteration);
}
#endif