/*--------------------------------------------------------------------------*/
/*! \file   nifti_tool.c
 *  \brief  a tool for nifti file perusal, manipulation and copying
 *          written by Rick Reynolds, SSCC, NIMH, January 2005
 * <pre>
 *
 * usage: nifti_tool [options] -infiles files...
 *
 * Via this tool, one should be able to:
 * 
 *       - copy a set of volumes (sub-bricks) from one dataset to another
 *       - copy a dataset, restricting some dimensions to given indices
 *
 *       - display the contents of a nifti_image (or various fields)
 *       - display the contents of a nifti1_header (or various fields)
 *       - display AFNI extensions (they are text)
 *       - display the time series at coordinates i,j,k
 *       - display the data from any collapsed image
 *
 *       - do a diff on two nifti_image structs (or various fields)
 *       - do a diff on two nifti1_header structs (or various fields)
 *
 *       - add an AFNI extension
 *       - remove any extension
 *
 *       - modify any field(s) of a nifti_image
 *       - modify any field(s) of a nifti1_struct
 *    
 * usage forms:
 *
 *   nifti_tool -help
 *   nifti_tool -help_hdr
 *   nifti_tool -help_nim
 *   nifti_tool -hist
 *   nifti_tool -ver
 *   nifti_tool -nifti_hist
 *   nifti_tool -nifti_ver
 *
 *   nifti_tool -check_hdr -infiles f1 ...
 *   nifti_tool -check_nim -infiles f1 ...

 *   nifti_tool -disp_exts -infiles f1 ...
 *   nifti_tool -disp_hdr [-field fieldname] [...] -infiles f1 ...
 *   nifti_tool -disp_nim [-field fieldname] [...] -infiles f1 ...
 *   nifti_tool -disp_ts I J K [-dci_lines] -infiles f1 ...
 *   nifti_tool -disp_ci I J K T U V W [-dci_lines] -infiles f1 ...
 *
 *   nifti_tool -diff_hdr [-field fieldname] [...] -infiles f1 f2
 *   nifti_tool -diff_nim [-field fieldname] [...] -infiles f1 f2
 *  
 *   nifti_tool -add_afni_ext    "extension in quotes" -infiles f1 ...
 *   nifti_tool -add_comment_ext "extension in quotes" -infiles f1 ...
 *   nifti_tool -rm_ext ext_index -infiles f1 ...
 *  
 *   nifti_tool -mod_hdr  [-mod_field fieldname new_val] [...] -infiles f1 ...
 *   nifti_tool -mod_nim  [-mod_field fieldname new_val] [...] -infiles f1 ...
 *  
 * </pre> */
/*-------------------------------------------------------------------------*/

/*! module history */
static char * g_history[] =
{
  "----------------------------------------------------------------------\n"
  "nifti_tool modification history:\n"
  "\n",
  "0.1  30 December 2004 [rickr]\n"
  "     (Rick Reynolds of the National Institutes of Health, SSCC/DIRP/NIMH)\n"
  "   - skeleton version: options read and printed\n"
  "\n",
  "1.0  07 January 2005 [rickr]\n"
  "   - initial release version\n"
  "\n",
  "1.1  14 January 2005 [rickr]\n"
  "   - changed all non-error/non-debug output from stderr to stdout\n"
  "       note: creates a mis-match between normal output and debug messages\n"
  "   - modified act_diff_hdrs and act_diff_nims to do the processing in\n"
  "       lower-level functions\n",
  "   - added functions diff_hdrs, diff_hdrs_list, diff_nims, diff_nims_list\n"
  "   - added function get_field, to return a struct pointer via a fieldname\n"
  "   - made 'quiet' output more quiet (no description on output)\n"
  "   - made hdr and nim_fields arrays global, so do not pass in main()\n"
  "   - return (from main()) after first act_diff() difference\n"
  "\n",
  "1.2  9 February 2005 [rickr] - minor\n"
  "   - defined a local NTL_FERR macro (so it does not come from nifti1_io.h)\n"
  "   - added new set_byte_order parameter to nifti_set_filenames\n"
  "\n",
  "1.3  23 February 2005 [rickr] - sourceforge.net merge\n"
  "   - moved to utils directory\n"
  "   - added simple casts of 3 pointers for -pedantic warnings\n"
  "   - added a doxygen comment for the file\n"
  "\n",
  "1.4  02 March 2005 [rickr] - small update\n"
  "   - no validation in nifti_read_header calls\n"
  "\n",
  "1.5  05 April 2005 [rickr] - small update\n"
  "   - refuse mod_hdr for gzipped files (we cannot do partial overwrites)\n"
  "\n",
  "1.6  08 April 2005 [rickr] - added cbl, cci and dts functionality\n"
  "   - added -cbl: 'copy brick list' dataset copy functionality\n"
  "   - added -ccd: 'copy collapsed data' dataset copy functionality\n"
  "   - added -disp_ts: 'disp time series' data display functionality\n"
  "   - moved raw data display to disp_raw_data()\n"
  "\n",
  "1.7  14 April 2005 [rickr] - added data display functionality\n" 
  "   - added -dci: 'display collapsed image' functionality\n"
  "   - modified -dts to use -dci\n"
  "   - modified and updated the help in use_full()\n"
  "   - changed copy_collapsed_dims to copy_collapsed_image, etc.\n",
  "   - fixed problem in disp_raw_data() for printing NT_DT_CHAR_PTR\n"
  "   - modified act_disp_ci():\n"
  "       o was act_disp_ts(), now displays arbitrary collapsed image data\n"
  "       o added missed debug filename act_disp_ci()\n"
  "       o can now save free() of data pointer for end of file loop\n",
  "   - modified disp_raw_data()\n"
  "       o takes a flag for whether to print newline\n"
  "       o trailing spaces and zeros are removed from printing floats\n"
  "   - added clear_float_zeros(), to remove trailing zeros\n"
  "\n",
  "1.8  19 April 2005 [rickr] - COMMENT extensions\n"
  "   - added int_list struct, and keep_hist,etypes,command fields to nt_opts\n"
  "   - added -add_comment_ext action\n"
  "   - allowed for removal of multiple extensions, including option of ALL\n"
  "   - added -keep_hist option, to store the command as a COMMENT extension\n",
  "     (includes fill_cmd_string() and add_int(), is done for all actions)\n"
  "   - added remove_ext_list(), for removing a list of extensions by indices\n"
  "   - added -strip action, to strip all extensions and descrip fields\n"
  "\n",
  "1.9  25 August 2005 [rickr] - const/string cleanup for warnings\n"
  "\n",
  "1.10 18 November 2005 [rickr] - added check_hdr and check_nim actions\n"
  "----------------------------------------------------------------------\n"
};
static char g_version[] = "version 1.10 (November 18, 2005)";
static int  g_debug = 1;

#define _NIFTI_TOOL_C_
#include "nifti1_io.h"
#include "nifti_tool.h"

#define NTL_FERR(func,msg,file)                                      \
            fprintf(stderr,"** ERROR (%s): %s '%s'\n",func,msg,file)

/* these are effectively constant, and are built only for verification */
field_s g_hdr_fields[NT_HDR_NUM_FIELDS];    /* nifti_1_header fields */
field_s g_nim_fields[NT_NIM_NUM_FIELDS];    /* nifti_image fields    */

int main( int argc, char * argv[] )
{
   nt_opts opts;
   int     rv;

   if( (rv = process_opts(argc, argv, &opts)) != 0)
      return rv;

   if( (rv = verify_opts(&opts, argv[0])) != 0 )
      return rv;

   /* now perform the requested action(s) */

   if( (rv = fill_hdr_field_array(g_hdr_fields)) != 0 )
      return rv;

   if( (rv = fill_nim_field_array(g_nim_fields)) != 0 )
      return rv;

   /* 'check' functions, first */
   if( opts.check_hdr || opts.check_nim ) /* allow for both */
      return act_check_hdrs(&opts);

   /* copy or dts functions */
   if( opts.cbl )             return act_cbl(&opts);  /* just return */
   if( opts.cci )             return act_cci(&opts);
   if( opts.dts || opts.dci ) return act_disp_ci(&opts);

   /* perform modifications early, in case we allow multiple actions */
   if( opts.strip     && ((rv = act_strip    (&opts)) != 0) ) return rv;

   if( opts.add_exts  && ((rv = act_add_exts (&opts)) != 0) ) return rv;
   if( opts.rm_exts   && ((rv = act_rm_ext   (&opts)) != 0) ) return rv;

   if( opts.mod_hdr   && ((rv = act_mod_hdrs (&opts)) != 0) ) return rv;
   if( opts.mod_nim   && ((rv = act_mod_nims (&opts)) != 0) ) return rv;

   /* if a diff, return wither a difference exists (like the UNIX command) */
   if( opts.diff_hdr  && ((rv = act_diff_hdrs(&opts)) != 0) ) return rv;
   if( opts.diff_nim  && ((rv = act_diff_nims(&opts)) != 0) ) return rv;

   /* last action type is display */
   if( opts.disp_exts && ((rv = act_disp_exts(&opts)) != 0) ) return rv;
   if( opts.disp_hdr  && ((rv = act_disp_hdrs(&opts)) != 0) ) return rv;
   if( opts.disp_nim  && ((rv = act_disp_nims(&opts)) != 0) ) return rv;

   return 0;
}

/*----------------------------------------------------------------------
 * process user options, return 0 on success
 *----------------------------------------------------------------------*/
int process_opts( int argc, char * argv[], nt_opts * opts )
{
   int ac;

   memset(opts, 0, sizeof(*opts));

   opts->prefix = NULL;
   opts->debug = 1;  /* init debug level to basic output */

   if( argc < 2 ) return usage(argv[0], USE_SHORT);

   /* terminal options are first, the rest are sorted */
   for( ac = 1; ac < argc; ac++ )
   {
      if( ! strncmp(argv[ac], "-help_hdr", 9) )
         return usage(argv[0], USE_FIELD_HDR);
      if( ! strncmp(argv[ac], "-help_nim", 9) )
         return usage(argv[0], USE_FIELD_NIM);
      if( ! strncmp(argv[ac], "-help", 5) )
         return usage(argv[0], USE_FULL);
      else if( ! strncmp(argv[ac], "-hist", 5) )
         return usage(argv[0], USE_HIST);
      else if( ! strncmp(argv[ac], "-ver", 2) )
         return usage(argv[0], USE_VERSION);
      else if( ! strncmp(argv[ac], "-nifti_hist", 11) )
      {
         nifti_disp_lib_hist();
         return 1;
      }
      else if( ! strncmp(argv[ac], "-nifti_ver", 10) )
      {
         nifti_disp_lib_version();
         return 1;
      }

      /* begin normal execution options... */
      else if( ! strncmp(argv[ac], "-add_afni_ext", 9) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-add_afni_ext");
         if( add_string(&opts->elist, argv[ac]) ) return 1; /* add extension */
         if( add_int(&opts->etypes, NIFTI_ECODE_AFNI) ) return 1;
         opts->add_exts = 1;
      }
      else if( ! strncmp(argv[ac], "-add_comment_ext", 9) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-add_comment_ext");
         if( add_string(&opts->elist, argv[ac]) ) return 1; /* add extension */
         if( add_int(&opts->etypes, NIFTI_ECODE_COMMENT) ) return 1;
         opts->add_exts = 1;
      }
      else if( ! strncmp(argv[ac], "-check_hdr", 10) )
         opts->check_hdr = 1;
      else if( ! strncmp(argv[ac], "-check_nim", 10) )
         opts->check_nim = 1;
      else if( ! strncmp(argv[ac], "-copy_brick_list", 11) ||
               ! strncmp(argv[ac], "-cbl", 4) )
      {
         opts->cbl = 1;
      }
      else if( ! strncmp(argv[ac], "-copy_collapsed_image", 10) ||
               ! strncmp(argv[ac], "-cci", 4) )
      {
         /* we need to read in the 7 dimension values */
         int index;
         opts->ci_dims[0] = 0;
         for( index = 1; index < 8; index++ )
         {
            ac++;
            CHECK_NEXT_OPT_MSG(ac,argc,"-cci","7 dimension values are requred");
            if( ! isdigit(argv[ac][0]) && strcmp(argv[ac],"-1") ){
               fprintf(stderr,"** -cci param %d (= '%s') is not a valid\n"
                       "   consider: 'nifti_tool -help'\n",index,argv[ac]);
               return 1;
            }
            opts->ci_dims[index] = atoi(argv[ac]);
         }

         opts->cci = 1;
      }
      else if( ! strncmp(argv[ac], "-debug", 6) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-debug");
         opts->debug = atoi(argv[ac]);
      }
      else if( ! strncmp(argv[ac], "-diff_hdr", 8) )
         opts->diff_hdr = 1;
      else if( ! strncmp(argv[ac], "-diff_nim", 8) )
         opts->diff_nim = 1;
      else if( ! strncmp(argv[ac], "-disp_exts", 7) )
         opts->disp_exts = 1;
      else if( ! strncmp(argv[ac], "-disp_hdr", 8) )
         opts->disp_hdr = 1;
      else if( ! strncmp(argv[ac], "-disp_nim", 8) )
         opts->disp_nim = 1;
      else if( ! strncmp(argv[ac], "-dci_lines", 6) ||   /* before -dts */ 
               ! strncmp(argv[ac], "-dts_lines", 6) ) 
      {
         opts->dci_lines = 1;
      }
      else if( ! strncmp(argv[ac], "-disp_collapsed_image", 10) ||
               ! strncmp(argv[ac], "-disp_ci", 8) )
      {
         /* we need to read in the 7 dimension values */
         int index;
         opts->ci_dims[0] = 0;
         for( index = 1; index < 8; index++ )
         {
            ac++;
            CHECK_NEXT_OPT_MSG(ac,argc,"-disp_ci",
                               "7 dimension values are requred");
            if( ! isdigit(argv[ac][0]) && strcmp(argv[ac],"-1") ){
               fprintf(stderr,"** -disp_ci param %d (= '%s') is not a valid\n"
                       "   consider: 'nifti_tool -help'\n",index,argv[ac]);
               return 1;
            }
            opts->ci_dims[index] = atoi(argv[ac]);
         }

         opts->dci = 1;
      }
      else if( ! strncmp(argv[ac], "-disp_ts", 10) ||
               ! strncmp(argv[ac], "-dts", 4) )
      {
         /* we need to read in the ijk indices into the ci_dims array */
         int index;
         for( index = 1; index <= 3; index++ )
         {
            ac++;
            CHECK_NEXT_OPT_MSG(ac,argc,"-dts","i,j,k indices are requied\n");
            if( ! isdigit(argv[ac][0]) ){
               fprintf(stderr,"** -dts param %d (= '%s') is not a number\n"
                       "   consider: 'nifti_tool -help'\n",index,argv[ac]);
               return 1;
            }
            opts->ci_dims[index] = atoi(argv[ac]);
         }
         /* and fill the rest of the array */
         opts->ci_dims[0] = 0;
         for( index = 4; index < 8; index++ ) opts->ci_dims[index] = -1;

         opts->dts = 1;
      }
      else if( ! strncmp(argv[ac], "-field", 2) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-field");
         if( add_string(&opts->flist, argv[ac]) ) return 1; /* add field */
      }
      else if( ! strncmp(argv[ac], "-infiles", 3) )
      {
         int count;
         /* for -infiles, get all next arguments until a '-' or done */
         ac++;
         for( count = 0; (ac < argc) && (argv[ac][0] != '-'); ac++, count++ )
            if( add_string(&opts->infiles, argv[ac]) ) return 1; /* add field */
         if( count > 0 && ac < argc ) ac--;  /* more options to process */
         if( g_debug > 2 ) fprintf(stderr,"+d have %d file names\n", count);
      }
      else if( ! strncmp(argv[ac], "-mod_field", 6) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-mod_field");
         if( add_string(&opts->flist, argv[ac]) ) return 1; /* add field */
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-mod_field (2)");
         if( add_string(&opts->vlist, argv[ac]) ) return 1; /* add value */
      }
      else if( ! strncmp(argv[ac], "-mod_hdr", 7) )
         opts->mod_hdr = 1;
      else if( ! strncmp(argv[ac], "-mod_nim", 7) )
         opts->mod_nim = 1;
      else if( ! strncmp(argv[ac], "-keep_hist", 5) )
         opts->keep_hist = 1;
      else if( ! strncmp(argv[ac], "-overwrite", 6) )
         opts->overwrite = 1;
      else if( ! strncmp(argv[ac], "-prefix", 4) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-prefix");
         opts->prefix = argv[ac];
      }
      else if( ! strncmp(argv[ac], "-quiet", 3) )
         opts->debug = 0;
      else if( ! strncmp(argv[ac], "-rm_ext", 7) )
      {
         ac++;
         CHECK_NEXT_OPT(ac, argc, "-rm_ext");
         if( strcmp(argv[ac],"ALL") == 0 )  /* special case, pass -1 */
         {
            if( add_string(&opts->elist, "-1") ) return 1;
         }
         else
         {
            int index = atoi(argv[ac]);
            if( (index != -1) && ((index > 1000) || !isdigit(*argv[ac])) ){
               fprintf(stderr,
                    "** '-rm_ext' requires an extension index (read '%s')\n",
                    argv[ac]);
               return 1;
            }
            if( add_string(&opts->elist, argv[ac]) ) return 1;
         }
         opts->rm_exts = 1;
      }
      else if( ! strncmp(argv[ac], "-strip_extras", 6) )
         opts->strip = 1;
      else
      {
         fprintf(stderr,"** unknown option: '%s'\n", argv[ac]);
         return 1;
      }
   }

   /* verify for programming purposes */
   if( opts->add_exts && ( opts->elist.len != opts->etypes.len ) )
   {
      fprintf(stderr,"** ext list length (%d) != etype length (%d)\n",
              opts->elist.len, opts->etypes.len);
      return 1;
   }

   g_debug = opts->debug;
   nifti_set_debug_level(g_debug);

   fill_cmd_string(opts, argc, argv);  /* copy this command */

   if( g_debug > 2 ) disp_nt_opts("options read: ", opts);

   return 0;
}


/*----------------------------------------------------------------------
 * verify that the options make sense
 *----------------------------------------------------------------------*/
int verify_opts( nt_opts * opts, char * prog )
{
   int ac, errs = 0;   /* number of requested action types */

   /* check that only one of disp, diff, mod or add_*_ext is used */
   ac  = (opts->check_hdr || opts->check_nim                   ) ? 1 : 0;
   ac += (opts->diff_hdr  || opts->diff_nim                    ) ? 1 : 0;
   ac += (opts->disp_hdr  || opts->disp_nim  || opts->disp_exts) ? 1 : 0;
   ac += (opts->mod_hdr   || opts->mod_nim                     ) ? 1 : 0;
   ac += (opts->add_exts  || opts->rm_exts                     ) ? 1 : 0;
   ac += (opts->strip                                          ) ? 1 : 0;
   ac += (opts->cbl                                            ) ? 1 : 0;
   ac += (opts->cci                                            ) ? 1 : 0;
   ac += (opts->dts       || opts->dci                         ) ? 1 : 0;

   if( ac < 1 )
   {
      fprintf(stderr,
              "** no action option, so nothing to do...\n"
              "   (try one of '-add...', '-diff...', '-disp...' or '-mod...')\n"
              "   (see '%s -help' for details)\n", prog);
      return 1;
   }
   else if( ac > 1 )
   {
      fprintf(stderr,
         "** only one action option is allowed, please use only one of:\n"
         "        '-add_...', '-check_...', '-diff_...', '-disp_...',\n"
         "        '-mod_...', '-strip', '-dts', '-cbl' or '-cci'\n"
         "   (see '%s -help' for details)\n", prog);
      return 1;
   }

   /* can modify nifti_1_header or nifti_image, but not both */
   if( opts->mod_hdr && opts->mod_nim )
   {
      fprintf(stderr,"** cannot use both '-mod_hdr' and '-mod_nim'\n");
      return 1;
   }

   /* can add or remove extensions, but not both */
   if( opts->add_exts && opts->rm_exts )
   {
      fprintf(stderr,"** cannot use both '-add_*_ext' and '-rm_ext'\n");
      return 1;
   }
   if( (opts->add_exts || opts->rm_exts) && opts->elist.len <= 0 )
   {
      fprintf(stderr,"** missing extensions to add or remove\n");
      return 1;
   }

   /* if modify, then we need fields and corresponding values */
   if( opts->mod_hdr || opts->mod_nim )
   {
      if( opts->flist.len <= 0 )
      {
         fprintf(stderr,"** missing field to modify (need '-mod_field' opt)\n");
         return 1;
      }
      if( opts->flist.len != opts->vlist.len )
      {
         fprintf(stderr,"** error: modifying %d fields with %d values\n",
                 opts->flist.len, opts->vlist.len);
         return 1;
      }
   }

   /* verify the number of files given for each of 4 action types */

   /* -diff_... : require nfiles == 2 */
   if( opts->diff_hdr || opts->diff_nim )
   {
     if( opts->infiles.len != 2 )
     {
      fprintf(stderr,"** '-diff_XXX' options require exactly 2 inputs files\n");
      return 1;
     }
   }
   /* if we are making changes, but not overwriting... */
   else if( (opts->elist.len > 0 || opts->mod_hdr || opts->mod_nim) &&
            !opts->overwrite )
   {
      if( opts->infiles.len > 1 )
      {
         fprintf(stderr,"** without -overwrite, only one input file may be"
                          " modified at a time\n");
         errs++;
      }
      if( ! opts->prefix )
      {
         fprintf(stderr,"** missing -prefix for output file\n");
         errs++;
      }
   }

   if( opts->dci_lines && ! opts->dts && ! opts->dci )
   {
      fprintf(stderr,"** option '-dci_lines' must only be used with '-dts'\n");
      errs++;
   }

   if( opts->infiles.len <= 0 ) /* in any case */
   {
      fprintf(stderr,"** missing input files (see -infiles option)\n");
      errs++;
   }

   if ( opts->overwrite && opts->prefix )
   {
      fprintf(stderr, "** please specify only one of -prefix and -overwrite\n");
      errs++;
   }

   if( errs ) return 1;

   if( g_debug > 1 ) fprintf(stderr,"+d options seem valid\n");

   return 0;
}


/*----------------------------------------------------------------------
 * re-assemble the command string into opts->command
 *----------------------------------------------------------------------*/
int fill_cmd_string( nt_opts * opts, int argc, char * argv[])
{
   char * cp;
   int    len, remain = NT_CMD_LEN;  /* NT_CMD_LEN is max command len */
   int    c, ac;
   int    has_space;  /* arguments containing space must be quoted */
   int    skip = 0;   /* counter to skip some of the arguments     */

   /* get the first argument separately */
   len = sprintf( opts->command, "\n  command: %s", argv[0] );
   cp = opts->command + len;
   remain -= len;

   /* get the rest, with special attention to input files */
   for( ac = 1; ac < argc; ac++ )
   {
      if( skip ){ skip--;  continue; }  /* then skip these arguments */

      len = strlen(argv[ac]);
      if( len + 3 >= remain ) {  /* extra 3 for space and possible '' */
         fprintf(stderr,"FCS: no space remaining for command, continuing...\n");
         return 1;
      }

      /* put the argument in, possibly with '' */

      has_space = 0;
      for( c = 0; c < len-1; c++ )
         if( isspace(argv[ac][c]) ){ has_space = 1; break; }
      if( has_space ) len = sprintf(cp, " '%s'", argv[ac]);
      else            len = sprintf(cp, " %s",   argv[ac]);

      remain -= len;

      /* infiles is okay, but after the *next* argument, we may skip files */
      /* (danger, will robinson!  hack alert!) */
      if( !strncmp(argv[ac-1],"-infiles",3) )
      {
         /* if more than 4 (just to be arbitrary) input files,
            include only the first and last */
         if( opts->infiles.len > 4 )
            skip = opts->infiles.len - 2;
      }

      cp += len;
   }

   if( g_debug > 1 ){
      fprintf(stderr,"+d filled command string, %d args, %d bytes\n",
              argc, (int)(cp - opts->command));
      if( g_debug > 2 ) fprintf(stderr,"%s\n", opts->command);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * - only bother to alloc one pointer at a time (don't need efficiency here)
 * - return 0 on success
 *----------------------------------------------------------------------*/
int add_int(int_list * ilist, int val)
{
   if( ilist->len == 0 ) ilist->list = NULL;  /* just to be safe */
   ilist->len++;
   ilist->list = (int *)realloc(ilist->list,ilist->len*sizeof(int));
   if( ! ilist->list ){
      fprintf(stderr,"** failed to alloc %d (int *) elements\n",ilist->len);
      return -1;
   }

   ilist->list[ilist->len-1] = val;

   return 0;
}


/*----------------------------------------------------------------------
 * - do not duplicate the string
 * - only bother to alloc one pointer at a time (don't need efficiency here)
 * - return 0 on success
 *----------------------------------------------------------------------*/
int add_string(str_list * slist, char * str)
{
   if( slist->len == 0 ) slist->list = NULL;  /* just to be safe */
   slist->len++;
   slist->list = (char **)realloc(slist->list,slist->len*sizeof(char *));
   if( ! slist->list ){
      fprintf(stderr,"** failed to alloc %d (char *) elements\n",slist->len);
      return -1;
   }

   slist->list[slist->len-1] = str;

   return 0;
}


/*----------------------------------------------------------------------
 * display information on using the program
 *----------------------------------------------------------------------*/
int usage(char * prog, int level)
{
   int c, len;
   if( level == USE_SHORT )
   {
      fprintf(stdout,"usage %s [options] -infiles files...\n", prog);
      fprintf(stdout,"usage %s -help\n", prog);
   }
   else if( level == USE_FULL )
      use_full("nifti_tool");  /* let's not allow paths in here */
   else if( level == USE_HIST )
   {
      len = sizeof(g_history)/sizeof(char *);
      for( c = 0; c < len; c++)
          fputs(g_history[c], stdout);
   }
   else if( level == USE_FIELD_HDR )
   {
      field_s nhdr_fields[NT_HDR_NUM_FIELDS];  /* just do it all here */

      fill_hdr_field_array(nhdr_fields);
      disp_field_s_list("nifti_1_header: ", nhdr_fields, NT_HDR_NUM_FIELDS);
   }
   else if( level == USE_FIELD_NIM )
   {
      field_s nim_fields[NT_NIM_NUM_FIELDS];

      fill_nim_field_array(nim_fields);
      disp_field_s_list("nifti_image: ", nim_fields, NT_NIM_NUM_FIELDS);
   }
   else if( level == USE_VERSION )
      fprintf(stdout, "%s, %s\n", prog, g_version);
   else
      fprintf(stdout,"** illegal level for usage(): %d\n", level);

   return 1;
}


/*----------------------------------------------------------------------
 * full usage
 *----------------------------------------------------------------------*/
int use_full(char * prog)
{
   printf(
   "nifti_tool\n"
   "\n"
   "   - display, modify or compare nifti structures in datasets\n"
   "   - copy a dataset by selecting a list of volumes from the original\n"
   "   - copy a dataset, collapsing any dimensions, each to a single index\n"
   "   - display a time series for a voxel, or more generally, the data\n"
   "       from any collapsed image, in ASCII text\n");
   printf(
   "\n"
   "  This program can be used to display information from nifti datasets,\n"
   "  to modify information in nifti datasets, to look for differences\n"
   "  between two nifti datasets (like the UNIX 'diff' command), and to copy\n"
   "  a dataset to a new one, either by restricting any dimensions, or by\n"
   "  copying a list of volumes (the time dimension) from a dataset.\n"
   "\n");
   printf(
   "  Only one action type is allowed, e.g. one cannot modify a dataset\n"
   "  and then take a 'diff'.\n"
   "\n");
   printf(
   "  one can display - any or all fields in the nifti_1_header structure\n"
   "                  - any or all fields in the nifti_image structure\n"
   "                  - the extensions in the nifti_image structure\n"
   "                  - the time series from a 4-D dataset, given i,j,k\n"
   "                  - the data from any collapsed image, given dims. list\n"
   "\n");
   printf(
   "  one can check   - perform internal check on the nifti_1_header struct\n"
   "                    (by nifti_hdr_looks_good())\n"
   "                  - perform internal check on the nifti_image struct\n"
   "                    (by nifti_nim_is_valid())\n"
   "\n");
   printf(
   "  one can modify  - any or all fields in the nifti_1_header structure\n"
   "                  - any or all fields in the nifti_image structure\n"
   "          add/rm  - any or all extensions in the nifti_image structure\n"
   "          remove  - all extensions and descriptions from the datasets\n"
   "\n");
   printf(
   "  one can compare - any or all field pairs of nifti_1_header structures\n"
   "                  - any or all field pairs of nifti_image structures\n"
   "\n"
   "  one can copy    - an arbitrary list of dataset volumes (time points)\n"
   "                  - a dataset, collapsing across arbitrary dimensions\n"
   "                    (restricting those dimensions to the given indices)\n"
   "\n");
   printf(
   "  Note: to learn about which fields exist in either of the structures,\n"
   "        or to learn a field's type, size of each element, or the number\n"
   "        of elements in the field, use either the '-help_hdr' option, or\n"
   "        the '-help_nim' option.  No further options are required.\n"
   "  ------------------------------\n");
   printf(
   "\n"
   "  usage styles:\n"
   "\n"
   "    nifti_tool -help                 : show this help\n"
   "    nifti_tool -help_hdr             : show nifti_1_header field info\n"
   "    nifti_tool -help_nim             : show nifti_image field info\n"
   "\n");
   printf(
   "    nifti_tool -ver                  : show the current version\n"
   "    nifti_tool -hist                 : show the modification history\n"
   "    nifti_tool -nifti_ver            : show the nifti library version\n"
   "    nifti_tool -nifti_hist           : show the nifti library history\n"
   "\n"
   "\n");
   printf(
   "    nifti_tool -check_hdr -infiles f1 ...\n"
   "    nifti_tool -check_nim -infiles f1 ...\n"
   "\n");
   printf(
   "    nifti_tool -copy_brick_list -infiles f1'[indices...]'\n"
   "    nifti_tool -copy_collapsed_image I J K T U V W -infiles f1\n"
   "\n");
   printf(
   "    nifti_tool -disp_hdr [-field FIELDNAME] [...] -infiles f1 ...\n"
   "    nifti_tool -disp_nim [-field FIELDNAME] [...] -infiles f1 ...\n"
   "    nifti_tool -disp_exts -infiles f1 ...\n"
   "    nifti_tool -disp_ts I J K [-dci_lines] -infiles f1 ...\n"
   "    nifti_tool -disp_ci I J K T U V W [-dci_lines] -infiles f1 ...\n"
   "\n");
   printf(
   "    nifti_tool -mod_hdr  [-mod_field FIELDNAME NEW_VAL] [...] -infiles f1\n"
   "    nifti_tool -mod_nim  [-mod_field FIELDNAME NEW_VAL] [...] -infiles f1\n"
   "\n"
   "    nifti_tool -add_afni_ext    'extension in quotes' [...] -infiles f1\n"
   "    nifti_tool -add_comment_ext 'extension in quotes' [...] -infiles f1\n"
   "    nifti_tool -rm_ext INDEX [...] -infiles f1 ...\n"
   "    nifti_tool -strip_extras -infiles f1 ...\n"
   "\n");
   printf(
   "    nifti_tool -diff_hdr [-field FIELDNAME] [...] -infiles f1 f2\n"
   "    nifti_tool -diff_nim [-field FIELDNAME] [...] -infiles f1 f2\n"
   "\n"
   "  ------------------------------\n");

   printf(
   "\n"
   "  selected examples:\n"
   "\n"
   "    checks header (for problems):\n"
   "\n"
   "       nifti_tool -check_hdr -infiles dset0.nii dset1.nii\n"
   "       nifti_tool -check_hdr -infiles *.nii *.hdr\n"
   "       nifti_tool -check_hdr -quiet -infiles *.nii *.hdr\n"
   "\n");
   printf(
   "    show header differences:\n"
   "\n"
   "       nifti_tool -diff_hdr -field dim -field intent_code  \\\n"
   "                  -infiles dset0.nii dset1.nii \n"
   "\n"
   "    display structures or fields:\n"
   "\n");
   printf(
   "       nifti_tool -disp_hdr -infiles dset0.nii dset1.nii dset2.nii\n"
   "       nifti_tool -disp_hdr -field dim -field descrip -infiles dset0.nii\n"
   "\n"
   "       nifti_tool -disp_exts -infiles dset0.nii dset1.nii dset2.nii\n"
   "\n"
   "       nifti_tool -disp_ts 23 0 172 -infiles dset1_time.nii\n"
   "\n"
   "       nifti_tool -disp_ci 23 0 172 -1 0 0 0 -infiles dset1_time.nii\n"
   "\n");
   printf(
   "    copy brick list, or copy collapsed image:\n"
   "\n"
   "       nifti_tool -cbl -prefix new_07.nii -infiles dset0.nii'[0,7]'\n"
   "       nifti_tool -cbl -prefix new_partial.nii \\\n"
   "                  -infiles dset0.nii'[3..$(2)]'\n"
   "\n"
   "       nifti_tool -cci 5 4 17 -1 -1 -1 -1 -prefix new_5_4_17.nii\n"
   "       nifti_tool -cci 5 0 17 -1 -1 2 -1  -keep_hist \\\n"
   "                    -prefix new_5_0_17_2.nii\n"
   "\n");
   printf(
   "    modify the header:\n"
   "\n"
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field dim '4 64 64 20 30 1 1 1 1'\n"
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field descrip 'beer, brats and cheese, mmmmm...'\n"
   "\n");
   printf(
   "    strip, add or remove extensions:\n"
   "\n"
   "       nifti_tool -strip -overwrite -infiles *.nii\n"
   "\n"
   "       nifti_tool -add_comment 'converted from MY_AFNI_DSET+orig' \\\n"
   "                  -prefix dnew -infiles dset0.nii\n"
   "\n");
   printf(
   "       nifti_tool -rm_ext ALL -prefix dset1 -infiles dset0.nii\n"
   "       nifti_tool -rm_ext 2 -rm_ext 3 -rm_ext 5 -overwrite \\\n"
   "                  -infiles dset0.nii\n"
   "\n"
   "  ------------------------------\n");
   printf(
   "\n"
   "  options for check actions:\n"
   "\n");
   printf(
   "    -check_hdr         : check for a valid nifti_1_header struct\n"
   "\n"
   "       This action is used to check the nifti_1_header structure for\n"
   "       problems.  The nifti_hdr_looks_good() function is used for the\n"
   "       test, and currently checks:\n"
   "       \n"
   "         dim[], sizeof_hdr, magic, datatype\n"
   "       \n"
   "       More tests can be requested of the author.\n"
   "\n");
   printf(
   "       e.g. perform checks on the headers of some datasets\n"
   "       nifti_tool -check_hdr -infiles dset0.nii dset1.nii\n"
   "       nifti_tool -check_hdr -infiles *.nii *.hdr\n"
   "       \n"
   "       e.g. add the -quiet option, so that only erros are reported\n"
   "       nifti_tool -check_hdr -quiet -infiles *.nii *.hdr\n"
   "\n");
   printf(
   "    -check_nim         : check for a valid nifti_image struct\n"
   "\n"
   "       This action is used to check the nifti_image structure for\n"
   "       problems.  This is tested via both nifti_convert_nhdr2nim()\n"
   "       and nifti_nim_is_valid(), though other functions are called\n"
   "       below them, of course.  Current checks are:\n"
   "\n");
   printf(
   "         dim[], sizeof_hdr, datatype, fname, iname, nifti_type\n"
   "       \n"
   "       Note that creation of a nifti_image structure depends on good\n"
   "       header fields.  So errors are terminal, meaning this check would\n"
   "       probably report at most one error, even if more exist.  The\n"
   "       -check_hdr action is more complete.\n"
   "\n");
   printf(
   "       More tests can be requested of the author.\n"
   "\n");
   printf(
   "             e.g. nifti_tool -check_nim -infiles dset0.nii dset1.nii\n"
   "             e.g. nifti_tool -check_nim -infiles *.nii *.hdr\n"
   "\n");
   printf(
   "  ------------------------------\n");

   printf(
   "\n"
   "  options for copy actions:\n"
   "\n"
   "    -copy_brick_list   : copy a list of volumes to a new dataset\n"
   "    -cbl               : (a shorter, alternative form)\n"
   "\n");
   printf(
   "       This action allows the user to copy a list of volumes (over time)\n"
   "       from one dataset to another.  The listed volumes can be in any\n"
   "       order and contain repeats, but are of course restricted to\n"
   "       the set of values {1, 2, ..., nt-1}, from dimension 4.\n"
   "\n");
   printf(
   "       This option is a flag.  The index list is specified with the input\n"
   "       dataset, contained in square brackets.  Note that square brackets\n"
   "       are special to most UNIX shells, so they should be contained\n"
   "       within single quotes.  Syntax of an index list:\n"
   "\n"
   "       notes:\n"
   "\n");
   printf(
   "         - indices start at zero\n"
   "         - indices end at nt-1, which has the special symbol '$'\n"
   "         - single indices should be separated with commas, ','\n"
   "             e.g. -infiles dset0.nii'[0,3,8,5,2,2,2]'\n"
   "         - ranges may be specified using '..' or '-' \n");
   printf(
   "             e.g. -infiles dset0.nii'[2..95]'\n"
   "             e.g. -infiles dset0.nii'[2..$]'\n"
   "         - ranges may have step values, specified in ()\n"
   "           example: 2 through 95 with a step of 3, i.e. {2,5,8,11,...,95}\n"
   "             e.g. -infiles dset0.nii'[2..95(3)]'\n"
   "\n");
   printf(
   "       This functionality applies only to 4-dimensional datasets.\n"
   "\n"
   "       e.g. to copy sub-bricks 0 and 7:\n"
   "       nifti_tool -cbl -prefix new_07.nii -infiles dset0.nii'[0,7]'\n"
   "\n"
   "       e.g. to copy an entire dataset:\n"
   "       nifti_tool -cbl -prefix new_all.nii -infiles dset0.nii'[0..$]'\n"
   "\n");
   printf(
   "       e.g. to copy every other time point, skipping the first three:\n"
   "       nifti_tool -cbl -prefix new_partial.nii \\\n"
   "                  -infiles dset0.nii'[3..$(2)]'\n"
   "\n"
   "\n"
   "    -copy_collapsed_image ... : copy a list of volumes to a new dataset\n"
   "    -cci I J K T U V W        : (a shorter, alternative form)\n"
   "\n");
   printf(
   "       This action allows the user to copy a collapsed dataset, where\n"
   "       some dimensions are collapsed to a given index.  For instance, the\n"
   "       X dimension could be collapsed to i=42, and the time dimensions\n"
   "       could be collapsed to t=17.  To collapse a dimension, set Di to\n"
   "       the desired index, where i is in {0..ni-1}.  Any dimension that\n"
   "       should not be collapsed must be listed as -1.\n"
   "\n");
   printf(
   "       Any number (of valid) dimensions can be collapsed, even down to a\n"
   "       a single value, by specifying enough valid indices.  The resulting\n"
   "       dataset will then have a reduced number of non-trivial dimensions.\n"
   "\n"
   "       Assume dset0.nii has nim->dim[8] = { 4, 64, 64, 21, 80, 1, 1, 1 }.\n"
   "       Note that this is a 4-dimensional dataset.\n"
   "\n");
   printf(
   "         e.g. copy the time series for voxel i,j,k = 5,4,17\n"
   "         nifti_tool -cci 5 4 17 -1 -1 -1 -1 -prefix new_5_4_17.nii\n"
   "\n"
   "         e.g. read the single volume at time point 26\n"
   "         nifti_tool -cci -1 -1 -1 26 -1 -1 -1 -prefix new_t26.nii\n"
   "\n");
   printf(
   "       Assume dset1.nii has nim->dim[8] = { 6, 64, 64, 21, 80, 4, 3, 1 }.\n"
   "       Note that this is a 6-dimensional dataset.\n"
   "\n"
   "         e.g. copy all time series for voxel i,j,k = 5,0,17, with v=2\n"
   "              (and add the command to the history)\n"
   "         nifti_tool -cci 5 0 17 -1 -1 2 -1  -keep_hist \\\n"
   "                    -prefix new_5_0_17_2.nii\n"
   "\n");
   printf(
   "         e.g. copy all data where i=3, j=19 and v=2\n"
   "              (I do not claim to know a good reason to do this)\n"
   "         nifti_tool -cci 3 19 -1 -1 -1 2 -1 -prefix new_mess.nii\n"
   "\n"
   "       See '-disp_ci' for more information (which displays/prints the\n"
   "       data, instead of copying it to a new dataset).\n"
   "\n"
   "  ------------------------------\n");

   printf(
   "\n"
   "  options for display actions:\n"
   "\n"
   "    -disp_hdr          : display nifti_1_header fields for datasets\n"
   "\n"
   "       This flag means the user wishes to see some of the nifti_1_header\n"
   "       fields in one or more nifti datasets. The user may want to specify\n"
   "       mutliple '-field' options along with this.  This option requires\n"
   "       one or more files input, via '-infiles'.\n"
   "\n");
   printf(
   "       If no '-field' option is present, all fields will be displayed.\n"
   "\n"
   "       e.g. to display the contents of all fields:\n"
   "       nifti_tool -disp_hdr -infiles dset0.nii\n"
   "       nifti_tool -disp_hdr -infiles dset0.nii dset1.nii dset2.nii\n"
   "\n"
   "       e.g. to display the contents of select fields:\n"
   "       nifti_tool -disp_hdr -field dim -infiles dset0.nii\n"
   "       nifti_tool -disp_hdr -field dim -field descrip -infiles dset0.nii\n"
   "\n");
   printf(
   "    -disp_nim          : display nifti_image fields for datasets\n"
   "\n"
   "       This flag option works the same way as the '-disp_hdr' option,\n"
   "       except that the fields in question are from the nifti_image\n"
   "       structure.\n"
   "\n");
   printf(
   "    -disp_exts         : display all AFNI-type extensions\n"
   "\n"
   "       This flag option is used to display all nifti_1_extension data,\n"
   "       for only those extensions of type AFNI (code = 4).  The only\n"
   "       other option used will be '-infiles'.\n"
   "\n");
   printf(
   "       e.g. to display the extensions in datasets:\n"
   "       nifti_tool -disp_exts -infiles dset0.nii\n"
   "       nifti_tool -disp_exts -infiles dset0.nii dset1.nii dset2.nii\n"
   "\n");
   printf(
   "    -disp_ts I J K    : display ASCII time series at i,j,k = I,J,K\n"
   "\n"
   "       This option is used to display the time series data for the voxel\n"
   "       at i,j,k indices I,J,K.  The data is displayed in text, either all\n"
   "       on one line (the default), or as one number per line (via the\n"
   "       '-dci_lines' option).\n"
   "\n");
   printf(
   "       Notes:\n"
   "\n"
   "         o This function applies only to 4-dimensional datasets.\n"
   "         o The '-quiet' option can be used to suppress the text header,\n"
   "           leaving only the data.\n"
   "         o This option is short for using '-disp_ci' (display collapsed\n"
   "           image), restricted to 4-dimensional datasets.  i.e. :\n"
   "               -disp_ci I J K -1 -1 -1 -1\n"
   "\n");
   printf(
   "       e.g. to display the time series at voxel 23, 0, 172:\n"
   "       nifti_tool -disp_ts 23 0 172            -infiles dset1_time.nii\n"
   "       nifti_tool -disp_ts 23 0 172 -dci_lines -infiles dset1_time.nii\n"
   "       nifti_tool -disp_ts 23 0 172 -quiet     -infiles dset1_time.nii\n"
   "\n");
   printf(
   "    -disp_collapsed_image  : display ASCII values for collapsed dataset\n"
   "    -disp_ci I J K T U V W : (a shorter, alternative form)\n"
   "\n"
   "       This option is used to display all of the data from a collapsed\n"
   "       image, given the dimension list.  The data is displayed in text,\n"
   "       either all on one line (the default), or as one number per line\n"
   "       (by using the '-dci_lines' flag).\n"
   "\n");
   printf(
   "       The '-quiet' option can be used to suppress the text header.\n"
   "\n"
   "       e.g. to display the time series at voxel 23, 0, 172:\n"
   "       nifti_tool -disp_ci 23 0 172 -1 0 0 0 -infiles dset1_time.nii\n"
   "\n"
   "       e.g. to display z-slice 14, at time t=68:\n"
   "       nifti_tool -disp_ci -1 -1 14 68 0 0 0 -infiles dset1_time.nii\n"
   "\n"
   "       See '-ccd' for more information, which copies such data to a new\n"
   "       dataset, instead of printing it to the terminal window.\n"
   "\n"
   "  ------------------------------\n");
   printf(
   "\n"
   "  options for modification actions:\n"
   "\n"
   "    -mod_hdr           : modify nifti_1_header fields for datasets\n"
   "\n"
   "       This action is used to modify some of the nifti_1_header fields in\n"
   "       one or more datasets.  The user must specify a list of fields to\n"
   "       modify via one or more '-mod_field' options, which include field\n"
   "       names, along with the new (set of) values.\n"
   "\n");
   printf(
   "       The user can modify a dataset in place, or use '-prefix' to\n"
   "       produce a new dataset, to which the changes have been applied.\n"
   "       It is recommended to normally use the '-prefix' option, so as not\n"
   "       to ruin a dataset.\n"
   "\n");
   printf(
   "       Note that some fields have a length greater than 1, meaning that\n"
   "       the field is an array of numbers, or a string of characters.  In\n"
   "       order to modify an array of numbers, the user must provide the\n"
   "       correct number of values, and contain those values in quotes, so\n"
   "       that they are seen as a single option.\n"
   "\n");
   printf(
   "       To modify a string field, put the string in quotes.\n"
   "\n"
   "       The '-mod_field' option takes a field_name and a list of values.\n"
   "\n"
   "       e.g. to modify the contents of various fields:\n"
   "\n");
   printf(
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field qoffset_x -17.325\n"
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field dim '4 64 64 20 30 1 1 1 1'\n"
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field descrip 'beer, brats and cheese, mmmmm...'\n"
   "\n");
   printf(
   "       e.g. to modify the contents of multiple fields:\n"
   "       nifti_tool -mod_hdr -prefix dnew -infiles dset0.nii  \\\n"
   "                  -mod_field qoffset_x -17.325 -mod_field slice_start 1\n"
   "\n"
   "       e.g. to modify the contents of multiple files (must overwrite):\n"
   "       nifti_tool -mod_hdr -overwrite -mod_field qoffset_x -17.325   \\\n"
   "                  -infiles dset0.nii dset1.nii\n"
   "\n");
   printf(
   "    -mod_nim          : modify nifti_image fields for datasets\n"
   "\n"
   "       This action option is used the same way that '-mod_hdr' is used,\n"
   "       except that the fields in question are from the nifti_image\n"
   "       structure.\n"
   "\n");
   printf(
   "    -strip_extras     : remove extensions and descriptions from datasets\n"
   "\n"
   "       This action is used to attempt to 'clean' a dataset of general\n"
   "       text, in order to make it more anonymous.  Extensions and the\n"
   "       nifti_image descrip field are cleared by this action.\n"
   "\n");
   printf(
   "       e.g. to strip all *.nii datasets in this directory:\n"
   "       nifti_tool -strip -overwrite -infiles *.nii\n"
   "\n"
   "  ------------------------------\n");
   printf(
   "\n"
   "  options for adding/removing extensions:\n"
   "\n"
   "    -add_afni_ext EXT : add an AFNI extension to the dataset\n"
   "\n"
   "       This option is used to add AFNI-type extensions to one or more\n"
   "       datasets.  This option may be used more than once to add more than\n"
   "       one extension.\n"
   "\n");
   printf(
   "       The '-prefix' option is recommended, to create a new dataset.\n"
   "       In such a case, only a single file may be taken as input.  Using\n"
   "       '-overwrite' allows the user to overwrite the current file, or\n"
   "       to add the extension(s) to multiple files, overwriting them.\n"
   "\n");
   printf(
   "       e.g. to add a generic AFNI extension:\n"
   "       nifti_tool -add_afni_ext 'wow, my first extension' -prefix dnew \\\n"
   "                  -infiles dset0.nii\n"
   "\n"
   "       e.g. to add multiple AFNI extensions:\n"
   "       nifti_tool -add_afni_ext 'wow, my first extension :)'      \\\n"
   "                  -add_afni_ext 'look, my second...'              \\\n"
   "                  -prefix dnew -infiles dset0.nii\n"
   "\n");
   printf(
   "       e.g. to add an extension, and overwrite the dataset:\n"
   "       nifti_tool -add_afni_ext 'some AFNI extension' -overwrite \\\n"
   "                  -infiles dset0.nii dset1.nii \n"
   "\n");
   printf(
   "    -add_comment_ext EXT : add a COMMENT extension to the dataset\n"
   "\n"
   "       This option is used to add COMMENT-type extensions to one or more\n"
   "       datasets.  This option may be used more than once to add more than\n"
   "       one extension.  This option may also be used with '-add_afni_ext'.\n"
   "\n");
   printf(
   "       The '-prefix' option is recommended, to create a new dataset.\n"
   "       In such a case, only a single file may be taken as input.  Using\n"
   "       '-overwrite' allows the user to overwrite the current file, or\n"
   "       to add the extension(s) to multiple files, overwriting them.\n"
   "\n");
   printf(
   "       e.g. to add a comment about the dataset:\n"
   "       nifti_tool -add_comment 'converted from MY_AFNI_DSET+orig' \\\n"
   "                  -prefix dnew                                    \\\n"
   "                  -infiles dset0.nii\n"
   "\n");
   printf(
   "       e.g. to add multiple extensions:\n"
   "       nifti_tool -add_comment  'add a comment extension'         \\\n"
   "                  -add_afni_ext 'and an AFNI XML style extension' \\\n"
   "                  -add_comment  'dataset copied from dset0.nii'   \\\n"
   "                  -prefix dnew -infiles dset0.nii\n"
   "\n");
   printf(
   "    -rm_ext INDEX     : remove the extension given by INDEX\n"
   "\n"
   "       This option is used to remove any single extension from the\n"
   "       dataset.  Multiple extensions require multiple options.\n"
   "\n"
   "       notes  - extension indices begin with 0 (zero)\n"
   "              - to view the current extensions, see '-disp_exts'\n"
   "              - all exensions can be removed using ALL or -1 for INDEX\n"
   "\n");
   printf(
   "       e.g. to remove the extension #0:\n"
   "       nifti_tool -rm_ext 0 -overwrite -infiles dset0.nii\n"
   "\n"
   "       e.g. to remove ALL extensions:\n"
   "       nifti_tool -rm_ext ALL -prefix dset1 -infiles dset0.nii\n"
   "       nifti_tool -rm_ext -1  -prefix dset1 -infiles dset0.nii\n"
   "\n");
   printf(
   "       e.g. to remove the extensions #2, #3 and #5:\n"
   "       nifti_tool -rm_ext 2 -rm_ext 3 -rm_ext 5 -overwrite \\\n"
   "                  -infiles dset0.nii\n"
   "\n"
   "  ------------------------------\n");

   printf(
   "\n"
   "  options for showing differences:\n"
   "\n"
   "    -diff_hdr         : display header field diffs between two datasets\n"
   "\n"
   "       This option is used to find differences between two datasets.\n"
   "       If any fields are different, the contents of those fields is\n"
   "       displayed (unless the '-quiet' option is used).\n"
   "\n");
   printf(
   "       A list of fields can be specified by using multiple '-field'\n"
   "       options.  If no '-field' option is given, all fields will be\n"
   "       checked.\n"
   "\n"
   "       Exactly two dataset names must be provided via '-infiles'.\n"
   "\n"
   "       e.g. to display all nifti_1_header field differences:\n"
   "       nifti_tool -diff_hdr -infiles dset0.nii dset1.nii\n"
   "\n");
   printf(
   "       e.g. to display selected nifti_1_header field differences:\n"
   "       nifti_tool -diff_hdr -field dim -field intent_code  \\\n"
   "                  -infiles dset0.nii dset1.nii \n"
   "\n"
   "    -diff_nim         : display nifti_image field diffs between datasets\n"
   "\n"
   "       This option works the same as '-diff_hdr', except that the fields\n"
   "       in question are from the nifti_image structure.\n"
   "\n"
   "  ------------------------------\n");

   printf(
   "\n"
   "  miscellaneous options:\n"
   "\n"
   "    -debug LEVEL      : set the debugging level\n"
   "\n"
   "       Level 0 will attempt to operate with no screen output, but errors.\n"
   "       Level 1 is the default.\n"
   "       Levels 2 and 3 give progressively more infomation.\n"
   "\n"
   "       e.g. -debug 2\n"
   "\n");
   printf(
   "    -field FIELDNAME  : provide a field to work with\n"
   "\n"
   "       This option is used to provide a field to display, modify or\n"
   "       compare.  This option can be used along with one of the action\n"
   "       options presented above.\n"
   "\n"
   "       See '-disp_hdr', above, for complete examples.\n"
   "\n"
   "       e.g. nifti_tool -field descrip\n"
   "       e.g. nifti_tool -field descrip -field dim\n"
   "\n");
   printf(
   "    -infiles file0... : provide a list of files to work with\n"
   "\n"
   "       This parameter is required for any of the actions, in order to\n"
   "       provide a list of files to process.  If input filenames do not\n"
   "       have an extension, the directory we be searched for any\n"
   "       appropriate files (such as .nii or .hdr).\n"
   "\n");
   printf(
   "       See '-mod_hdr', above, for complete examples.\n"
   "\n"
   "       e.g. nifti_tool -infiles file0.nii\n"
   "       e.g. nifti_tool -infiles file1.nii file2 file3.hdr\n"
   "\n");
   printf(
   "    -mod_field NAME 'VALUE_LIST' : provide new values for a field\n"
   "\n"
   "       This parameter is required for any the modification actions.\n"
   "       If the user wants to modify any fields of a dataset, this is\n"
   "       where the fields and values are specified.\n"
   "\n");
   printf(
   "       NAME is a field name (in either the nifti_1_header structure or\n"
   "       the nifti_image structure).  If the action option is '-mod_hdr',\n"
   "       then NAME must be the name of a nifti_1_header field.  If the\n"
   "       action is '-mod_nim', NAME must be from a nifti_image structure.\n"
   "\n");
   printf(
   "       VALUE_LIST must be one or more values, as many as are required\n"
   "       for the field, contained in quotes if more than one is provided.\n"
   "\n"
   "       Use 'nifti_tool -help_hdr' to get a list of nifti_1_header fields\n"
   "       Use 'nifti_tool -help_nim' to get a list of nifti_image fields\n"
   "\n"
   "       See '-mod_hdr', above, for complete examples.\n"
   "\n");
   printf(
   "       e.g. modifying nifti_1_header fields:\n"
   "            -mod_field descrip 'toga, toga, toga'\n"
   "            -mod_field qoffset_x 19.4 -mod_field qoffset_z -11\n"
   "            -mod_field pixdim '1 0.9375 0.9375 1.2 1 1 1 1'\n"
   "\n");
   printf(
   "    -keep_hist         : add the command as COMMENT (to the 'history')\n"
   "\n"
   "        When this option is used, the current command will be added\n"
   "        as a NIFTI_ECODE_COMMENT type extension.  This provides the\n"
   "        ability to keep a history of commands affecting a dataset.\n"
   "\n"
   "       e.g. -keep_hist\n"
   "\n");
   printf(
   "    -overwrite        : any modifications will be made to input files\n"
   "\n"
   "       This option is used so that all field modifications, including\n"
   "       extension additions or deletions, will be made to the files that\n"
   "       are input.\n"
   "\n");
   printf(
   "       In general, the user is recommended to use the '-prefix' option\n"
   "       to create new files.  But if overwriting the contents of the\n"
   "       input files is prefered, this is how to do it.\n"
   "\n"
   "       See '-mod_hdr' or '-add_afni_ext', above, for complete examples.\n"
   "\n"
   "       e.g. -overwrite\n"
   "\n");
   printf(
   "    -prefix           : specify an output file to write change into\n"
   "\n"
   "       This option is used to specify an output file to write, after\n"
   "       modifications have been made.  If modifications are being made,\n"
   "       then either '-prefix' or '-overwrite' is required.\n"
   "\n"
   "       If no extension is given, the output extension will be '.nii'.\n"
   "\n");
   printf(
   "       e.g. -prefix new_dset\n"
   "       e.g. -prefix new_dset.nii\n"
   "       e.g. -prefix new_dset.hdr\n"
   "\n"
   "    -quiet            : report only errors or requested information\n"
   "\n"
   "       This option is equivalent to '-debug 0'.\n"
   "\n"
   "  ------------------------------\n");

   printf(
   "\n"
   "  basic help options:\n"
   "\n"
   "    -help             : show this help\n"
   "\n"
   "       e.g.  nifti_tool -help\n"
   "\n"
   "    -help_hdr         : show nifti_1_header field info\n"
   "\n"
   "       e.g.  nifti_tool -help_hdr\n"
   "\n"
   "    -help_nim         : show nifti_image field info\n"
   "\n"
   "       e.g.  nifti_tool -help_nim\n");

   printf(
   "\n"
   "    -ver              : show the program version number\n"
   "\n"
   "       e.g.  nifti_tool -ver\n"
   "\n"
   "    -hist             : show the program modification history\n"
   "\n"
   "       e.g.  nifti_tool -hist\n"
   "\n");
   printf(
   "    -nifti_ver        : show the nifti library version number\n"
   "\n"
   "       e.g.  nifti_tool -nifti_ver\n"
   "\n"
   "    -nifti_hist       : show the nifti library modification history\n"
   "\n"
   "       e.g.  nifti_tool -nifti_hist\n"
   "\n"
   "  ------------------------------\n"
   "\n"
   "  R. Reynolds\n"
   "  compiled: %s\n"
   "  %s\n\n",
   __DATE__, g_version );

   return 1;
}


/*----------------------------------------------------------------------
 * display the contents of the struct and all lists
 *----------------------------------------------------------------------*/
int disp_nt_opts(char * mesg, nt_opts * opts)
{
   int c;

   if( mesg ) fputs(mesg, stderr);
   if( ! opts )
   {
      fprintf(stderr,"** disp_nt_opts: missing opts\n");
      return -1;
   }

   fprintf(stderr,"nt_opts @ %p\n"
                  "   check_hdr, check_nim = %d, %d\n"
                  "   diff_hdr, diff_nim   = %d, %d\n"
                  "   disp_hdr, disp_nim   = %d, %d\n"
                  "   disp_exts            = %d\n"
                  "   add_exts, rm_exts    = %d, %d\n"
                  "   mod_hdr,  mod_nim    = %d, %d\n"
                  "   cbl, cci             = %d, %d\n"
                  "   dts, dci_lines       = %d, %d\n",
            (void *)opts,
            opts->check_hdr, opts->check_nim,
            opts->diff_hdr, opts->diff_nim, opts->disp_hdr, opts->disp_nim,
            opts->disp_exts, opts->add_exts, opts->rm_exts,
            opts->mod_hdr, opts->mod_nim, opts->cbl, opts->cci,
            opts->dts, opts->dci_lines );

   fprintf(stderr,"   ci_dims[8]          = ");
   disp_raw_data(opts->ci_dims, DT_INT32, 8, ' ', 1);

   fprintf(stderr,"\n"
                  "   debug, keep_hist    = %d, %d\n"
                  "   overwrite           = %d\n"
                  "   prefix              = '%s'\n",
            opts->debug, opts->keep_hist, opts->overwrite,
            opts->prefix ? opts->prefix : "(NULL)" );

   fprintf(stderr,"   elist   (length %d)  :\n", opts->elist.len);
   for( c = 0; c < opts->elist.len; c++ )
       fprintf(stderr,"      %d : %s\n", c, opts->elist.list[c]);

   fprintf(stderr,"   etypes  (length %d)  : ", opts->etypes.len);
   disp_raw_data(opts->etypes.list, DT_INT32, opts->etypes.len, ' ', 0);
   fputc('\n',stderr);

   fprintf(stderr,"   flist   (length %d)  :\n", opts->flist.len);
   for( c = 0; c < opts->flist.len; c++ )
       fprintf(stderr,"      %d : %s\n", c, opts->flist.list[c]);

   fprintf(stderr,"   vlist   (length %d)  :\n", opts->vlist.len);
   for( c = 0; c < opts->vlist.len; c++ )
       fprintf(stderr,"      %d : %s\n", c, opts->vlist.list[c]);

   fprintf(stderr,"   infiles (length %d)  :\n", opts->infiles.len);
   for( c = 0; c < opts->infiles.len; c++ )
       fprintf(stderr,"      %d : %s\n", c, opts->infiles.list[c]);

   fprintf(stderr,"   command len         : %d\n",(int)strlen(opts->command));

   return 0;
}


/*----------------------------------------------------------------------
 * For each file, add all extensions with type NIFTI_ECODE_AFNI.
 * Though it should not matter, copy the trailing null characters.
 *----------------------------------------------------------------------*/
int act_add_exts( nt_opts * opts )
{
   nifti_image      * nim;
   int                fc, ec;

   if( g_debug > 2 ){
      fprintf(stderr,"+d adding %d extensions to %d files...\n"
                     "   extension types are: ",
              opts->elist.len, opts->infiles.len);
      disp_raw_data(opts->etypes.list, DT_INT32, opts->etypes.len, ' ', 1);
   }

   if( opts->prefix && opts->infiles.len != 1 ){
      fprintf(stderr,"** error: we have a prefix but %d files\n",
              opts->infiles.len);
      return 1;
   }

   if( opts->elist.len <= 0 ) return 0;

   for( fc = 0; fc < opts->infiles.len; fc++ )
   {
      nim = nifti_image_read( opts->infiles.list[fc], 1 );
      if( !nim ) return 1;  /* errors come from the library */

      for( ec = 0; ec < opts->elist.len; ec++ ){
         if( nifti_add_extension(nim, opts->elist.list[ec],
                   strlen(opts->elist.list[ec]), opts->etypes.list[ec]) ){
            nifti_image_free(nim);
            return 1;
         }
      }

      if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                             strlen(opts->command), NIFTI_ECODE_COMMENT) )
         fprintf(stderr,"** failed to add command to image as extension\n");

      if( opts->prefix &&
          nifti_set_filenames(nim, opts->prefix, !opts->overwrite, 1) )
      {
         nifti_image_free(nim);
         return 1;
      }

      if( g_debug > 1 )
         fprintf(stderr,"+d writing %s with %d new extension(s)\n",
                 opts->infiles.list[fc], opts->elist.len);

      nifti_image_write(nim);
      nifti_image_free(nim);
   }

   if( g_debug > 0 )
      fprintf(stderr,"+d added %d extension(s) to %d files\n",
              opts->elist.len, opts->infiles.len);

   return 0;
}


/*----------------------------------------------------------------------
 * For each file, strip the extra fields.
 *
 * Clear extensions and descrip field.  No other generic strings will get
 * passed to nifti_1_header struct.
 *
 * - this may make the datasets more anonymous
 * - no history is appended here
 *----------------------------------------------------------------------*/
int act_strip( nt_opts * opts )
{
   nifti_image      * nim;
   int                fc;

   if( g_debug > 2 )
      fprintf(stderr,"+d stripping extras from %d files\n", opts->infiles.len);

   if( opts->prefix && opts->infiles.len != 1 ){
      fprintf(stderr,"** error: we have a prefix but %d files\n",
              opts->infiles.len);
      return 1;
   }

   for( fc = 0; fc < opts->infiles.len; fc++ )
   {
      nim = nifti_image_read( opts->infiles.list[fc], 1 );
      if( !nim ) return 1;  /* errors come from the library */

      /* now remove the extensions */
      nifti_free_extensions(nim);
      memset(nim->descrip, 0, 80);

      if( opts->prefix &&
          nifti_set_filenames(nim, opts->prefix, !opts->overwrite, 1) ){
         nifti_image_free(nim);
         return 1;
      }

      if( g_debug > 1 )
         fprintf(stderr,"+d writing %s without extensions or 'descrip'\n",
                 nim->fname);

      nifti_image_write(nim);

      if( g_debug > 3 ) nifti_image_infodump(nim);
      nifti_image_free(nim);
   }

   if( g_debug > 0 )
      fprintf(stderr,"+d stripped extras from %d files\n", opts->infiles.len);

   return 0;
}


/*----------------------------------------------------------------------
 * For each file, remove the given extension for the given indices.
 *
 * Note that index = -1 means to remove them all.
 *----------------------------------------------------------------------*/
int act_rm_ext( nt_opts * opts )
{
   nifti_image      * nim;
   int                fc, ext_ind, num_ext;

   if( g_debug > 2 )
      fprintf(stderr,"+d removing %d extensions from %d files...\n",
              opts->elist.len, opts->infiles.len);

   if( opts->elist.len <= 0 ) return 0;

   if( opts->prefix && opts->infiles.len != 1 ){
      fprintf(stderr,"** error: we have a prefix but %d files\n",
              opts->infiles.len);
      return 1;
   }
   else if( opts->overwrite && opts->infiles.len != 1 &&
            strcmp(opts->elist.list[0], "-1") ) {
      fprintf(stderr,"** error: for multiple files, can only delete ALL\n");
      return 1;
   }

   ext_ind = atoi(opts->elist.list[0]);
   if( ext_ind < -1 ){
      fprintf(stderr,"** bad extension index to remove: %d\n", ext_ind);
      return 1;
   }

   if( g_debug > 1 ) fprintf(stderr,"+d removing extension index %d\n",ext_ind);

   for( fc = 0; fc < opts->infiles.len; fc++ )
   {
      nim = nifti_image_read( opts->infiles.list[fc], 1 );
      if( !nim ) return 1;  /* errors come from the library */

      /* now remove the extensions */
      if( remove_ext_list(nim, opts->elist.list, opts->elist.len) )
         return 1;

      if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                             strlen(opts->command), NIFTI_ECODE_COMMENT) )
         fprintf(stderr,"** failed to add command to image as extension\n");

      if( opts->prefix &&
          nifti_set_filenames(nim, opts->prefix, !opts->overwrite, 1) ){
         nifti_image_free(nim);
         return 1;
      }

      if( g_debug > 1 )
         fprintf(stderr,"+d writing %s with %d fewer extension(s)\n",
                 nim->fname, ext_ind == -1 ? num_ext : opts->elist.len);

      nifti_image_write(nim);
      nifti_image_free(nim);
   }

   if( g_debug > 0 )
      fprintf(stderr,"+d removed %s extension(s) from %d files\n",
              ext_ind == -1 ? "ALL" : "1", opts->infiles.len);

   return 0;
}


/*----------------------------------------------------------------------
 * remove extensions by index
 *
 * return: 0 on success, -1 on failure
 *----------------------------------------------------------------------*/
int remove_ext_list( nifti_image * nim, char ** elist, int len )
{
   int * marks;
   int   c, ec, extval;

   if( len > nim->num_ext ){
      fprintf(stderr, "** cannot remove %d exts from image '%s' with only %d\n",
              len, nim->fname, nim->num_ext);
      return -1;
   }

   if( len <= 0 ){
      fprintf(stderr,"** REL: (%d) no extensions to remove?\n",len);
      return -1;
   }

   extval = atoi(elist[0]);  /* check the first value */

   /* first special case, elist[0] == -1 */
   if( extval == -1 )
   {
      if( g_debug > 1 )
          fprintf(stderr,"+d removing ALL (%d) extensions from '%s'\n",
                  nim->num_ext, nim->fname );
      nifti_free_extensions(nim);
      return 0;
   }

   if( g_debug > 2 )
      fprintf(stderr,"+d removing %d exts from '%s'\n", len, nim->fname );

   if( ! (marks = (int *)calloc(nim->num_ext, sizeof(int))) ) {
      fprintf(stderr,"** failed to alloc %d marks\n",nim->num_ext);
      return -1;
   }

   /* mark all extensions for removal */
   for( ec = 0; ec < len; ec++ )
   {
      extval = atoi(elist[ec]);

      if( extval < 0 || extval >= nim->num_ext ){
         fprintf(stderr,"** ext #%d (= %d) is out of range [0,%d] for %s\n",
                 ec, extval, nim->num_ext-1, nim->fname);
         free(marks); return -1;
      }

      if( marks[extval] ){
         fprintf(stderr,"** ext #%d (= %d) is a duplicate", ec, extval);
         free(marks); return -1;
      }

      marks[extval]++;
   }

   /* now remove them - count from top down to do lazy programming */
   for( ec = nim->num_ext-1; ec >= 0; ec-- )
   {
      if( !marks[ec] ) continue;   /* do not delete this one */

      if( g_debug > 2 )
         disp_nifti1_extension("+d removing ext: ",nim->ext_list+ec,-1);

      /* delete this data, and shift the list down (yeah, inefficient) */
      if( nim->ext_list[ec].edata ) free( nim->ext_list[ec].edata );

      /* move anything above down one */
      for( c = ec+1; c < nim->num_ext; c++ )
         nim->ext_list[c-1] = nim->ext_list[c];

      nim->num_ext--;
   }

   if( g_debug > 3 ) fprintf(stderr,"-d done removing extensions\n");

   if( nim->num_ext == 0 ){  /* did we trash the only extension? */
      if( g_debug > 1 )
         fprintf(stderr,"-d removed ALL extensions from %s\n",nim->fname);
      free(nim->ext_list);
      nim->ext_list = NULL;
   }

   return 0;
}


/*----------------------------------------------------------------------
 * check for diffs between all fields in opts->flist, or in the
 * entire nifti_1_header
 *
 * if quiet mode (debug == 0) return on first diff
 *
 * return: 1 if diffs exist, 0 otherwise
 *----------------------------------------------------------------------*/
int act_diff_hdrs( nt_opts * opts )
{
   nifti_1_header * nhdr0, * nhdr1;
   int              diffs = 0;

   if( opts->infiles.len != 2 ){
      fprintf(stderr,"** -diff_hdr requires 2 -infiles, have %d\n",
              opts->infiles.len);
      return 1;
   }

   if( g_debug > 2 )
      fprintf(stderr,"-d nifti_1_header diff between %s and %s...\n",
              opts->infiles.list[0], opts->infiles.list[1]);

   /* get the nifiti headers (but do not validate them) */

   nhdr0 = nifti_read_header(opts->infiles.list[0], NULL, 0);
   if( ! nhdr0 ) return 1;  /* errors have been printed */

   nhdr1 = nifti_read_header(opts->infiles.list[1], NULL, 0);
   if( ! nhdr1 ){ free(nhdr0); return 1; }

   if( g_debug > 1 )
      fprintf(stderr,"\n-d nifti_1_header diffs between '%s' and '%s'...\n",
              opts->infiles.list[0], opts->infiles.list[1]);

   if( opts->flist.len <= 0 )
      diffs = diff_hdrs(nhdr0, nhdr1, g_debug > 0);
   else
      diffs = diff_hdrs_list(nhdr0, nhdr1, &opts->flist, g_debug > 0);

   if( diffs == 0 && g_debug > 1 )
      fprintf(stderr,"+d no differences found\n");
   else if ( g_debug > 2 )
      fprintf(stderr,"+d %d differences found\n", diffs);

   free(nhdr0);
   free(nhdr1);

   return (diffs > 0);
}


/*----------------------------------------------------------------------
 * check for diffs between all fields in opts->flist, or in the
 * entire nifti_image
 *
 * if quiet mode (debug == 0) return on first diff
 *
 * return: 1 if diffs exist, 0 otherwise
 *----------------------------------------------------------------------*/
int act_diff_nims( nt_opts * opts )
{
   nifti_image * nim0, * nim1;
   int           diffs = 0;

   if( opts->infiles.len != 2 ){
      fprintf(stderr,"** -diff_nim requires 2 -infiles, have %d\n",
              opts->infiles.len);
      return 1;
   }

   if( g_debug > 2 )
      fprintf(stderr,"-d nifti_image diff between %s and %s...\n",
              opts->infiles.list[0], opts->infiles.list[1]);

   /* get the nifiti images */

   nim0 = nifti_image_read(opts->infiles.list[0], 0);
   if( ! nim0 ) return 1;  /* errors have been printed */

   nim1 = nifti_image_read(opts->infiles.list[1], 0);
   if( ! nim1 ){ free(nim0); return 1; }

   if( g_debug > 1 )
      fprintf(stderr,"\n-d nifti_image diffs between '%s' and '%s'...\n",
              opts->infiles.list[0], opts->infiles.list[1]);

   if( opts->flist.len <= 0 )
      diffs = diff_nims(nim0, nim1, g_debug > 0);
   else
      diffs = diff_nims_list(nim0, nim1, &opts->flist, g_debug > 0);

   if( diffs == 0 && g_debug > 1 )
      fprintf(stderr,"+d no differences found\n");
   else if ( g_debug > 2 )
      fprintf(stderr,"+d %d differences found\n", diffs);

   nifti_image_free(nim0);
   nifti_image_free(nim1);

   return (diffs > 0);
}


/*----------------------------------------------------------------------
 * for each file, read nifti1_header
 *   if checking header, check it
 *   if checking nifti_image, convert and check it
 *----------------------------------------------------------------------*/
int act_check_hdrs( nt_opts * opts )
{
   nifti_1_header *  nhdr;
   nifti_image    *  nim;
   int               filenum, rv;

   if( g_debug > 2 )
      fprintf(stderr,"-d checking hdrs/nims for %d nifti datasets...\n",
              opts->infiles.len);

   for( filenum = 0; filenum < opts->infiles.len; filenum++ )
   {
      /* do not validate the header structure */
      nhdr = nifti_read_header(opts->infiles.list[filenum], NULL, 0);
      if( !nhdr ) continue;  /* errors are printed from library */

      if( opts->check_hdr )
      {
          if( g_debug > 1 )
             fprintf(stdout,"\nchecking nifti_1_header for file '%s'\n",
                     opts->infiles.list[filenum]);

          rv = nifti_hdr_looks_good(nhdr);

          if( rv && g_debug > 0 )  /* if quiet, no GOOD response */
             printf("header IS GOOD for file %s\n",opts->infiles.list[filenum]);
          else if( ! rv )
             printf("header FAILURE for file %s\n",opts->infiles.list[filenum]);
      }

      if( opts->check_nim )
      {
          nim = nifti_convert_nhdr2nim(*nhdr, opts->infiles.list[filenum]);
          if( !nim ) continue;  /* errors are printed from library */
          
          if( g_debug > 1 )
             fprintf(stdout,"\nchecking nifti_image for file '%s'\n",
                     opts->infiles.list[filenum]);

          rv = nifti_nim_is_valid(nim, 1); /* complain about errors */

          if( rv && g_debug > 0 )  /* if quiet, no GOOD response */
             printf("nifti_image IS GOOD for file %s\n",
                    opts->infiles.list[filenum]);
          else if( ! rv )
             printf("nifti_image FAILURE for file %s\n",
                    opts->infiles.list[filenum]);

          free(nim);
      }

      free(nhdr);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * display all extensions for each dataset
 *----------------------------------------------------------------------*/
int act_disp_exts( nt_opts * opts )
{
   nifti_image * nim;
   char          mesg[32];
   int           ec, fc;

   if( g_debug > 2 )
      fprintf(stderr,"-d displaying all extensions for %d files...\n",
              opts->infiles.len);

   for( fc = 0; fc < opts->infiles.len; fc++ )
   {
      nim = nifti_image_read(opts->infiles.list[fc], 0);
      if( !nim ) return 1;  /* errors are printed from library */

      if( g_debug > 0 )
         fprintf(stdout,"header file '%s', num_ext = %d\n",
                 nim->fname, nim->num_ext);
      for( ec = 0; ec < nim->num_ext; ec++ )
      {
         sprintf(mesg, "    ext #%d : ", ec);
         disp_nifti1_extension(mesg, nim->ext_list + ec, -1);
      }

      nifti_image_free(nim);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * for each file, read nifti1_header and display all fields
 *----------------------------------------------------------------------*/
int act_disp_hdrs( nt_opts * opts )
{
   nifti_1_header *  nhdr;
   field_s        *  fnhdr;
   char           ** sptr;
   int               nfields, filenum, fc;

   /* set the number of fields to display */
   nfields = opts->flist.len > 0 ? opts->flist.len : NT_HDR_NUM_FIELDS;

   if( g_debug > 2 )
      fprintf(stderr,"-d displaying %d fields for %d nifti datasets...\n",
              nfields, opts->infiles.len);

   for( filenum = 0; filenum < opts->infiles.len; filenum++ )
   {
      /* do not validate the header structure */
      nhdr = nifti_read_header(opts->infiles.list[filenum], NULL, 0);
      if( !nhdr ) return 1;  /* errors are printed from library */

      if( g_debug > 0 )
         fprintf(stdout,"\nheader file '%s', num_fields = %d\n",
                 opts->infiles.list[filenum], nfields);
      if( g_debug > 1 )
         fprintf(stderr,"-d header is: %s\n",
                 nifti_hdr_looks_good(nhdr) ? "valid" : "invalid");

      if( opts->flist.len <= 0 ) /* then display all fields */
         disp_field("\nall fields:\n", g_hdr_fields, nhdr, nfields, g_debug>0);
      else  /* print only the requested fields... */
      {
         /* must locate each field before printing it */
         sptr = opts->flist.list;
         for( fc = 0; fc < opts->flist.len; fc++ )
         {
            fnhdr = get_hdr_field(*sptr, filenum == 0);
            if( fnhdr ) disp_field(NULL, fnhdr, nhdr, 1, g_debug>0 && fc == 0);
            sptr++;
         }
      }

      free(nhdr);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * for each file, get nifti_image and display all fields
 *----------------------------------------------------------------------*/
int act_disp_nims( nt_opts * opts )
{
   nifti_image *  nim;
   field_s     *  fnim;
   char        ** sptr;
   int            nfields, filenum, fc;

   /* set the number of fields to display */
   nfields = opts->flist.len > 0 ? opts->flist.len : NT_NIM_NUM_FIELDS;

   if( g_debug > 2 )
      fprintf(stderr,"-d displaying %d fields for %d nifti datasets...\n",
              nfields, opts->infiles.len);

   for( filenum = 0; filenum < opts->infiles.len; filenum++ )
   {
      nim = nifti_image_read(opts->infiles.list[filenum], 0);
      if( !nim ) return 1;  /* errors are printed from library */
                                                                                
      if( g_debug > 0 )
         fprintf(stdout,"\nheader file '%s', num_fields = %d, fields:\n\n",
                 nim->fname, nfields);

      if( opts->flist.len <= 0 ) /* then display all fields */
         disp_field("all fields:\n", g_nim_fields, nim, nfields, g_debug > 0);
      else  /* print only the requested fields... */
      {
         /* must locate each field before printing it */
         sptr = opts->flist.list;
         for( fc = 0; fc < opts->flist.len; fc++ )
         {
            fnim = get_nim_field(*sptr, filenum == 0);
            if( fnim ) disp_field(NULL, fnim, nim, 1, g_debug > 0 && fc == 0);
            sptr++;
         }
      }

      nifti_image_free(nim);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * - read header
 * - modify header
 * - if -prefix duplicate file
 * - else if swapped, swap back
 * - overwrite file header      (allows (danger-of) no evaluation of data)
 *----------------------------------------------------------------------*/
int act_mod_hdrs( nt_opts * opts )
{
   nifti_1_header * nhdr;
   nifti_image    * nim;         /* for reading/writing entire datasets */
   int              filec, swap;
   char           * fname, * dupname;
   char             func[] = { "act_mod_hdrs" };
 
   if( g_debug > 2 )
      fprintf(stderr,"-d modifying %d fields for %d nifti headers...\n",
              opts->flist.len, opts->infiles.len);
   if( opts->flist.len <= 0 || opts->infiles.len <= 0 ) return 0;

   for( filec = 0; filec < opts->infiles.len; filec++ )
   {
      fname = opts->infiles.list[filec];  /* for convenience and mod file */

      if( nifti_is_gzfile(fname) ){
         fprintf(stderr,"** sorry, cannot modify a zipped file: %s\n", fname);
         continue;
      }

      /* do not validate the header structure */
      nhdr = nifti_read_header(fname, &swap, 0);
      if( !nhdr ) return 1;

      if( g_debug > 1 )
      {
         fprintf(stderr,"-d modifying %d fields of '%s' header\n",
                 opts->flist.len, fname);
         fprintf(stderr,"-d header is: %s\n",
                 nifti_hdr_looks_good(nhdr) ? "valid" : "invalid");
      }

      /* okay, let's actually trash the data fields */
      if( modify_all_fields(nhdr, opts, g_hdr_fields, NT_HDR_NUM_FIELDS) )
      {
         free(nhdr);
         return 1;
      }

      dupname = NULL;                     /* unless we duplicate file   */

      /* possibly duplicate the current dataset before writing new header */
      if( opts->prefix )
      {
         nim = nifti_image_read(fname, 1); /* get data */
         if( !nim ) {
            fprintf(stderr,"** failed to dup file '%s' before modifying\n",
                    fname);
            return 1;
         }
         if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                                strlen(opts->command), NIFTI_ECODE_COMMENT) )
               fprintf(stderr,"** failed to add command to image as exten\n");
         if( nifti_set_filenames(nim, opts->prefix, 1, 1) )
         {
            NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
            nifti_image_free(nim);
            return 1;
         }
         dupname = nifti_strdup(nim->fname);  /* so we know to free it */
         fname = dupname;
         nifti_image_write(nim);  /* create the duplicate file */
         /* if we added a history note, get the new offset into the header */
         if( opts->keep_hist ) nhdr->vox_offset = nim->iname_offset;
         nifti_image_free(nim);
      }
      else if ( swap )
         swap_nifti_header(nhdr, NIFTI_VERSION(*nhdr));

      /* if all is well, overwrite header in fname dataset */
      (void)write_hdr_to_file(nhdr, fname); /* errors printed in function */

      if( dupname ) free(dupname);
      free(nhdr);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * - read image w/data, modify and write
 *----------------------------------------------------------------------*/
int act_mod_nims( nt_opts * opts )
{
   nifti_image    * nim;         /* for reading/writing entire datasets */
   int              filec;
   char             func[] = { "act_mod_nims" };
 
   if( g_debug > 2 )
      fprintf(stderr,"-d modifying %d fields for %d nifti images...\n",
              opts->flist.len, opts->infiles.len);
   if( opts->flist.len <= 0 || opts->infiles.len <= 0 ) return 0;

   for( filec = 0; filec < opts->infiles.len; filec++ )
   {
      nim = nifti_image_read(opts->infiles.list[filec], 1); /* with data */

      if( g_debug > 1 )
         fprintf(stderr,"-d modifying %d fields from '%s' image\n",
                 opts->flist.len, opts->infiles.list[filec]);

      /* okay, let's actually trash the data fields */
      if( modify_all_fields(nim, opts, g_nim_fields, NT_NIM_NUM_FIELDS) )
      {
         nifti_image_free(nim);
         return 1;
      }

      /* add command as COMMENT extension */
      if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                             strlen(opts->command), NIFTI_ECODE_COMMENT) )
         fprintf(stderr,"** failed to add command to image as extension\n");

      /* possibly duplicate the current dataset before writing new header */
      if( opts->prefix )
         if( nifti_set_filenames(nim, opts->prefix, 1, 1) )
         {
            NTL_FERR(func,"failed to set prefix for new file: ",opts->prefix);
            nifti_image_free(nim);
            return 1;
         }

      nifti_image_write(nim);  /* and write it out, piece of cake :) */
      nifti_image_free(nim);
   }

   return 0;
}


/*----------------------------------------------------------------------
 * overwrite nifti_1_header in the given file
 *----------------------------------------------------------------------*/
int write_hdr_to_file( nifti_1_header * nhdr, char * fname )
{
   znzFile fp;
   size_t  bytes;
   char    func[] = { "write_hdr_to_file" };
   int     rv = 0;

   fp = znzopen(fname,"r+b",nifti_is_gzfile(fname));
   if( znz_isnull(fp) ){
      NTL_FERR(func, "failed to re-open mod file", fname);
      return 1;
   }

   bytes = znzwrite(nhdr, 1, sizeof(nifti_1_header), fp);
   if( bytes != sizeof(nifti_1_header)){
      NTL_FERR(func, "failed to write header to file",fname);
      fprintf(stderr,"  - wrote %d of %d bytes\n",
              (int)bytes,(int)sizeof(nifti_1_header));
      rv = 1;
   }

   if( g_debug > 3 )
      disp_nifti_1_header("+d writing new header to file : ", nhdr);

   znzclose(fp);

   return rv;
}


/*----------------------------------------------------------------------
 * modify all fields in the list
 *----------------------------------------------------------------------*/
int modify_all_fields( void * basep, nt_opts * opts, field_s * fields, int flen)
{
   field_s * fp;
   int       fc, lc;  /* field and list counters */

   if( opts->flist.len <= 0 ) return 0;
   if( opts->flist.len != opts->vlist.len ){
      fprintf(stderr,"** have %d fields but %d new values\n",
              opts->flist.len, opts->vlist.len);
      return 1;
   }

   for( lc = 0; lc < opts->flist.len; lc++ )
   {
      /* is it in the list? */
      fp = fields;
      for( fc = 0; fc < flen; fc++, fp++ )
         if( strcmp(opts->flist.list[lc], fp->name) == 0 ) break;

      if( fc == flen )    /* do no modifications on failure */
      {
         fprintf(stderr,"** field '%s' not found in structure\n",
                 opts->flist.list[lc]);
         return 1;
      }

      if( modify_field( basep, fp, opts->vlist.list[lc]) )
         return 1;
   }

   return 0;
}


/*----------------------------------------------------------------------
 * modify a single field with the given value field
 *
 * pointer fields are not allowed here
 *----------------------------------------------------------------------*/
int modify_field(void * basep, field_s * field, char * data)
{
   float   fval;
   char  * posn = data;
   int     val, max, fc, nchars;

   if( g_debug > 1 )
      fprintf(stderr,"+d modifying field '%s' with '%s'\n", field->name, data);

   if( !data || strlen(data) == 0 )
   {
      fprintf(stderr,"** no data for '%s' field modification\n",field->name);
      return 1;
   }

   switch( field->type )
   {
         case DT_UNKNOWN:
         case NT_DT_POINTER:
         case NT_DT_CHAR_PTR:
         case NT_DT_EXT_PTR:
         default:
            fprintf(stderr,"** refusing to modify a pointer field, '%s'\n",
                    field->name);
            return 1;

         case DT_INT8:
         {
            max = 127;
            for( fc = 0; fc < field->len; fc++ )
            {
               if( sscanf(posn, " %d%n", &val, &nchars) != 1 )
               {
                  fprintf(stderr,"** found %d of %d modify values\n",
                          fc,field->len);
                  return 1;
               }
               if( val > max || val < -(max+1) )
               {
                  fprintf(stderr,
                    "** mod val #%d (= %d) outside byte range [-%d,%d]\n",
                    fc, val, max+1, max);
                  return 1;
               }
               /* otherwise, we're good */
               (((char *)basep + field->offset))[fc] = (char)val;
               if( g_debug > 1 )
                  fprintf(stderr,"+d setting posn %d of '%s' to %d\n",
                          fc, field->name, val);
               posn += nchars;
            }
         }
         break;

         case DT_INT16:
         {
            max = 32767;
            for( fc = 0; fc < field->len; fc++ )
            {
               if( sscanf(posn, " %d%n", &val, &nchars) != 1 )
               {
                  fprintf(stderr,"** found %d of %d modify values\n",
                          fc,field->len);
                  return 1;
               }
               if( val > max || val < -(max+1) )
               {
                  fprintf(stderr,
                    "** mod val #%d (= %d) outside byte range [-%d,%d]\n",
                    fc, val, max+1, max);
                  return 1;
               }
               /* otherwise, we're good */
               ((short *)((char *)basep + field->offset))[fc] = (short)val;
               if( g_debug > 1 )
                  fprintf(stderr,"+d setting posn %d of '%s' to %d\n",
                          fc, field->name, val);
               posn += nchars;
            }
         }
         break;

         case DT_INT32:
         {
            for( fc = 0; fc < field->len; fc++ )
            {
               if( sscanf(posn, " %d%n", &val, &nchars) != 1 )
               {
                  fprintf(stderr,"** found %d of %d modify values\n",
                          fc,field->len);
                  return 1;
               }
               ((int *)((char *)basep + field->offset))[fc] = val;
               if( g_debug > 1 )
                  fprintf(stderr,"+d setting posn %d of '%s' to %d\n",
                          fc, field->name, val);
               posn += nchars;
            }
         }
         break;

         case DT_FLOAT32:
         {
            for( fc = 0; fc < field->len; fc++ )
            {
               if( sscanf(posn, " %f%n", &fval, &nchars) != 1 )
               {
                  fprintf(stderr,"** found %d of %d modify values\n",
                          fc,field->len);
                  return 1;
               }
               /* otherwise, we're good */
               ((float *)((char *)basep + field->offset))[fc] = fval;
               if( g_debug > 1 )
                  fprintf(stderr,"+d setting posn %d of '%s' to %f\n",
                          fc, field->name, fval);
               posn += nchars;
            }
         }
         break;

         case NT_DT_STRING:
         {
            char * dest = (char *)basep + field->offset;
            nchars = strlen(data);
            strncpy(dest, data, field->len);
            if( nchars < field->len )  /* clear the rest */
               memset(dest+nchars, '\0', field->len-nchars);
         }
         break;
   }

   return 0;
}


/*----------------------------------------------------------------------
 * fill the nifti_1_header field list
 *----------------------------------------------------------------------*/
int fill_hdr_field_array( field_s * nh_fields )
{
   nifti_1_header   nhdr;
   field_s        * nhf = nh_fields;
   int              rv, errs;

   memset(nhf, 0, NT_HDR_NUM_FIELDS*sizeof(field_s));

   /* this macro takes (TYPE, NAME, NUM) and does:
         fill_field(nhdr, TYPE, NT_OFF(nhdr,NAME), NUM, "NAME");
         nhf++;
   */
   errs = 0;
   NT_SFILL(nhdr, nhf, DT_INT32,     sizeof_hdr,     1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, data_type,     10, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, db_name,       18, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT32,     extents,        1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     session_error,  1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, regular,        1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT8,      dim_info,       1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, DT_INT16,     dim,            8, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   intent_p1,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   intent_p2,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   intent_p3,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     intent_code,    1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, DT_INT16,     datatype,       1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     bitpix,         1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     slice_start,    1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   pixdim,         8, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   vox_offset,     1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   scl_slope,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   scl_inter,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     slice_end,      1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, DT_INT8,      slice_code,     1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT8,      xyzt_units,     1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   cal_max,        1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   cal_min,        1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   slice_duration, 1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   toffset,        1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT32,     glmax,          1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT32,     glmin,          1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, NT_DT_STRING, descrip,       80, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, aux_file,      24, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     qform_code,     1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_INT16,     sform_code,     1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, DT_FLOAT32,   quatern_b,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   quatern_c,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   quatern_d,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   qoffset_x,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   qoffset_y,      1, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   qoffset_z,      1, rv);  errs += rv;

   NT_SFILL(nhdr, nhf, DT_FLOAT32,   srow_x,         4, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   srow_y,         4, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, DT_FLOAT32,   srow_z,         4, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, intent_name,   16, rv);  errs += rv;
   NT_SFILL(nhdr, nhf, NT_DT_STRING, magic,          4, rv);  errs += rv;

   if( errs > 0 ){
      fprintf(stderr, "** %d fill_fields errors!\n", errs);
      return 1;
   }

   /* failure here is a serious problem */
   if( check_total_size("nifti_1_header test: ", nh_fields,
                        NT_HDR_NUM_FIELDS, sizeof(nhdr)) )
      return 1;

   if( g_debug > 3 )
      disp_field_s_list("nh_fields: ", nh_fields, NT_HDR_NUM_FIELDS);

   return 0;
}


/*----------------------------------------------------------------------
 * fill the nifti_image field list
 *----------------------------------------------------------------------*/
int fill_nim_field_array( field_s * nim_fields )
{
   nifti_image   nim;
   field_s     * nif = nim_fields;
   int           rv, errs;

   memset(nif, 0, NT_NIM_NUM_FIELDS*sizeof(field_s));

   errs = 0;

   NT_SFILL(nim, nif, DT_INT32,             ndim,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nx,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               ny,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nz,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nt,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nu,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nv,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,               nw,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,              dim,  8, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,             nvox,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,           nbyper,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,         datatype,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dx,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dy,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dz,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dt,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             du,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dv,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,             dw,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,         pixdim,  8, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      scl_slope,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      scl_inter,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        cal_min,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        cal_max,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,       qform_code,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,       sform_code,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,         freq_dim,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,        phase_dim,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,        slice_dim,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,       slice_code,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,      slice_start,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,        slice_end,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32, slice_duration,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      quatern_b,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      quatern_c,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      quatern_d,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      qoffset_x,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      qoffset_y,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      qoffset_z,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,           qfac,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        qto_xyz, 16, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        qto_ijk, 16, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        sto_xyz, 16, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        sto_ijk, 16, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,        toffset,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,        xyz_units,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,       time_units,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,       nifti_type,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,      intent_code,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      intent_p1,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      intent_p2,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_FLOAT32,      intent_p3,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_STRING,  intent_name, 16, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_STRING,      descrip, 80, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_STRING,     aux_file, 24, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_CHAR_PTR,      fname,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_CHAR_PTR,      iname,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,     iname_offset,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,         swapsize,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,        byteorder,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_POINTER,        data,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, DT_INT32,          num_ext,  1, rv);  errs += rv;
   NT_SFILL(nim, nif, NT_DT_EXT_PTR,    ext_list,  1, rv);  errs += rv;

   if( errs > 0 ){
      fprintf(stderr, "** %d fill_fields errors "
                      "(note that pointers get aligned)\n", errs);
      return 1;
   }

   if( g_debug > 3 )  /* failure here is not an error condition */
       check_total_size("nifti_image test: ", nim_fields,
                        NT_NIM_NUM_FIELDS, sizeof(nim));

   if( g_debug > 3 )
      disp_field_s_list("nim_fields: ", nim_fields, NT_NIM_NUM_FIELDS);

   return 0;
}


/*----------------------------------------------------------------------
 * compare sizes to offset, including total
 *----------------------------------------------------------------------*/
int check_total_size( char * mesg, field_s * fields, int nfields, int tot_size )
{
   field_s * fp;
   int       c, total;
   int       bad_offs;

   total = 0;
   bad_offs = 0;
   for( c = 0, fp = fields; c < nfields; c++, fp++ ){
      if( fp->offset != total ){
         if( g_debug > 2 )
            fprintf(stderr,"** bad offset for field '%s'\n"
                           "   offset = %d, total = %d\n",
                           fp->name, fp->offset, total);
         bad_offs++;
      }

      total += fp->size * fp->len;
   }

   if( g_debug > 1  || (g_debug > 0 && bad_offs > 0) ){
      fputs(mesg, stderr);  c = 0;
      if( bad_offs > 0 ){
         fprintf(stderr,"** found %d bad offsets\n", bad_offs);  c++; }
      if( total != tot_size ){
         fprintf(stderr,"** computed total %d not equal to struct size %d\n",
                 total, tot_size);   c++; }
      if( c == 0 ) fputs("... okay\n", stderr);
   }

   if( bad_offs > 0 ) return 1;

   return 0;
}


/*----------------------------------------------------------------------
 * fill the field structure with the given data
 *----------------------------------------------------------------------*/
int fill_field( field_s * fp, int type, int offset, int num, char * name )
{
   fp->type   = type;
   fp->offset = offset;
   fp->size   = 1;     /* init before check */
   fp->len    = num;
   
   strncpy(fp->name, name, NT_FIELD_NAME_LEN-1);

   switch( type ){
      case DT_UNKNOWN:
      case DT_INT8:
      case NT_DT_STRING:
         fp->size = 1;
         break;

      case DT_INT16:
         fp->size = 2;
         break;

      case DT_INT32:
      case DT_FLOAT32:
         fp->size = 4;
         break;

      case NT_DT_POINTER:
      case NT_DT_CHAR_PTR:
      case NT_DT_EXT_PTR:
         fp->size = (int)sizeof(void *);
         break;

      default:
         fprintf(stderr,"** fill_field: invalid type %d\n", type );
         return 1;
   }

   return 0;
}


/*----------------------------------------------------------------------
 * display the contents of all of the field structures
 *----------------------------------------------------------------------*/
char * field_type_str( int type )
{
   if( type == DT_INT8 )        return "DT_INT8";
   if( type == DT_INT16 )       return "DT_INT16";
   if( type == DT_INT32 )       return "DT_INT32";
   if( type == DT_FLOAT32 )     return "DT_FLOAT32";
   if( type == NT_DT_STRING )   return "NT_DT_STRING";
   if( type == NT_DT_POINTER )  return "NT_DT_POINTER";
   if( type == NT_DT_CHAR_PTR ) return "NT_DT_CHAR_PTR"; /* longest: 14 */
   if( type == NT_DT_EXT_PTR )  return "NT_DT_EXT_PTR";

   return "DT_UNKNOWN";  /* for DT_UNKNOWN, or as an else */
}

#define NT_MAX_DT_STR_LEN 14

/*----------------------------------------------------------------------
 * display the contents of all of the field structures
 *----------------------------------------------------------------------*/
int disp_field_s_list( char * mesg, field_s * fp, int nfields )
{
   int c;

   if( mesg ) fputs(mesg, stdout);

   fprintf(stdout," %d fields:\n"
           "   name                  size   len   offset   type\n"
           "   -------------------   ----   ---   ------   --------------\n",
           nfields);

   for( c = 0; c < nfields; c++, fp++ )
      fprintf(stdout,"   %-*s  %4d    %3d   %4d     %-14s\n",
                     NT_FIELD_NAME_LEN-1, fp->name, fp->size, fp->len,
                     fp->offset, field_type_str(fp->type));

   return 0;
}


/*----------------------------------------------------------------------
 * display the contents of all of the field structures
 *----------------------------------------------------------------------*/
int disp_field(char *mesg, field_s *fieldp, void * str, int nfields, int header)
{
   field_s * fp;
   int       c;

   if( mesg ) fputs(mesg, stdout);

   if( header && g_debug > 0 ){
      fprintf(stdout, "  name                offset  nvals  values\n");
      fprintf(stdout, "  ------------------- ------  -----  ------\n");
   }

   fp = fieldp;
   for( c = 0; c < nfields; c++, fp++ )
   {
      /* start by displaying the field information */
      if( g_debug > 0 )
         fprintf(stdout, "  %-*.*s %4d    %3d    ",
                      NT_FIELD_NAME_LEN-1, NT_FIELD_NAME_LEN-1, fp->name,
                      fp->offset, fp->len);

      /* now, print the value(s), depending on the type */
      switch( fp->type ){
         case DT_UNKNOWN:
         default:
            fprintf(stdout,"(unknown data type)\n");
            break;

         case DT_INT8:    case DT_UINT8:
         case DT_INT16:   case DT_UINT16:
         case DT_INT32:   case DT_UINT32:
         case DT_FLOAT32: case DT_FLOAT64:
            disp_raw_data((char *)str+fp->offset, fp->type, fp->len, ' ', 1);
            break;
                
         case NT_DT_POINTER:
            fprintf(stdout,"(raw data of unknown type)\n");
            break;

         case NT_DT_CHAR_PTR:  /* look for string of length <= 40 */
         {
            char * sp;
            int    len;

            /* start by sucking the pointer stored here */
            sp = *(char **)((char *)str + fp->offset);

            if( ! sp ){ fprintf(stdout,"(NULL)\n");  break; }  /* anything? */

            /* see if we have a printable string here */
            for(len = 0; len <= 40 && *sp && isprint(*sp); len++, sp++ )
               ;
            if( len > 40 )
               fprintf(stdout,"(apparent long string)\n");
            else if ( len == 0 )
               fprintf(stdout,"(empty string)\n");
            else if( *sp && !isprint(*sp) )  /* if no termination, it's bad */
               fprintf(stdout,"(non-printable string)\n");
            else  /* woohoo!  a good string */
               fprintf(stdout,"'%.40s'\n",*(char **)((char *)str + fp->offset));
            break;
         }

         case NT_DT_EXT_PTR:
         {
            nifti1_extension * extp;

            /* yank the address sitting there into extp */
            extp = *(nifti1_extension **)((char *)str + fp->offset);

            /* the user may use -disp_exts to display all of them */
            if( extp ) disp_nifti1_extension(NULL, extp, 6);
            else fprintf(stdout,"(NULL)\n");
            break;
         }

         case NT_DT_STRING:
         {
            char * charp = (char *)str + fp->offset;
            fprintf(stdout,"%.*s\n", fp->len, charp);
            break;
         }
      }
   }

   return 0;
}


/*----------------------------------------------------------------------
 * no display, just return whether any fields differ
 *----------------------------------------------------------------------*/
int diff_field(field_s *fieldp, void * str0, void * str1, int nfields)
{
   field_s * fp;
   char    * cp0, * cp1;
   int       fnum, c, size;

   fp = fieldp;
   for( fnum = 0; fnum < nfields; fnum++, fp++ )
   {
      switch( fp->type ){
         case DT_UNKNOWN:     /* all basic types are easy */
         case DT_INT8:
         case DT_INT16:
         case DT_INT32:
         case DT_FLOAT32:
         case NT_DT_STRING:
            size = fp->size * fp->len;  /* total field size */
            cp0 = (char *)str0 + fp->offset;
            cp1 = (char *)str1 + fp->offset;
            for( c = 0; c < size; c++, cp0++, cp1++ )
               if( *cp0 != *cp1 ) break;

            if(c < size) return 1;  /* found a diff */
  
            break;

         case NT_DT_POINTER:     /* let's pass on these - no diff */
         case NT_DT_CHAR_PTR:
            
            break;

         case NT_DT_EXT_PTR:
         {
            nifti1_extension * ext0, * ext1;

            ext0 = *(nifti1_extension **)((char *)str0 + fp->offset);
            ext1 = *(nifti1_extension **)((char *)str1 + fp->offset);

            if( ! ext0 && ! ext1 ) break;     /* continue on */

            if( ext0 && ! ext1 )   return 1;  /* pointer diff is diff */
            if( ! ext0 && ext1 )   return 1;

            /* just check size and type for a single extension */
            if( ext0->esize != ext1->esize ) return 1;
            if( ext0->ecode != ext1->ecode ) return 1;

            break;
         }
      }
   }

   return 0;   /* no diffs found */
}


/*----------------------------------------------------------------------
 * display a single extension
 *----------------------------------------------------------------------*/
int disp_nifti1_extension(char *mesg, nifti1_extension * ext, int maxlen)
{
   int len;
   if( mesg ) fputs(mesg, stdout);

   if( !ext )
   {
      fprintf(stderr,"** no extension to display\n");
      return 1;
   }

   fprintf(stdout,"ecode = %d, esize = %d, edata = ",
           ext->ecode, ext->esize);

   if( !ext->edata )
      fprintf(stdout,"(NULL)\n");
   else if ( ext->ecode == NIFTI_ECODE_AFNI ||
             ext->ecode == NIFTI_ECODE_COMMENT )
   {
      len = ext->esize-8;
      if( maxlen >= 0 && len > maxlen ) len = maxlen;
      fprintf(stdout,"%.*s\n", len, (char *)ext->edata);
   }
   else
      fprintf(stdout,"(unknown data type)\n");

   fflush(stdout);

   return 0;
}


/*----------------------------------------------------------------------
 * return the appropritate pointer into the g_hdr_fields struct
 *----------------------------------------------------------------------*/
field_s * get_hdr_field( char * fname, int show_fail )
{
   field_s * fp;
   int       c;

   if( ! fname || *fname == '\0' ) return NULL;

   fp = g_hdr_fields;
   for( c = 0; c < NT_HDR_NUM_FIELDS; c++, fp++ )
      if( strcmp(fname, fp->name) == 0 ) break;

   if( c == NT_HDR_NUM_FIELDS )
   {
      if( show_fail > 0 )
         fprintf(stderr,"** get_hdr_field: field not found in hdr: %s\n",fname);
      return NULL;
   }

   return fp;
}


/*----------------------------------------------------------------------
 * return the appropritate pointer into the g_hdr_fields struct
 *----------------------------------------------------------------------*/
field_s * get_nim_field( char * fname, int show_fail )
{
   field_s * fp;
   int       c;

   if( ! fname || *fname == '\0' ) return NULL;

   fp = g_nim_fields;
   for( c = 0; c < NT_NIM_NUM_FIELDS; c++, fp++ )
      if( strcmp(fname, fp->name) == 0 ) break;

   if( c == NT_NIM_NUM_FIELDS )
   {
      if( show_fail > 0 )
         fprintf(stderr,"** get_nim_field: field not found in hdr: %s\n",fname);
      return NULL;
   }

   return fp;
}


/*----------------------------------------------------------------------
 * return the number of fields that differ
 *----------------------------------------------------------------------*/
int diff_hdrs( nifti_1_header * s0, nifti_1_header * s1, int display )
{
   field_s * fp = g_hdr_fields;
   int       c, ndiff = 0;

   for( c = 0; c < NT_HDR_NUM_FIELDS; c++, fp++ )
      if( diff_field(fp, s0, s1, 1) )
      {
         if( display ) disp_field(NULL, fp, s0, 1, ndiff == 0);
         if( display ) disp_field(NULL, fp, s1, 1, 0);
         ndiff++;
      }

   return ndiff;
}


/*----------------------------------------------------------------------
 * return the number of fields that differ
 *----------------------------------------------------------------------*/
int diff_nims( nifti_image * s0, nifti_image * s1, int display )
{
   field_s * fp = g_nim_fields;
   int       c, ndiff = 0;

   for( c = 0; c < NT_NIM_NUM_FIELDS; c++, fp++ )
      if( diff_field(fp, s0, s1, 1) )
      {
         if( display ) disp_field(NULL, fp, s0, 1, ndiff == 0);
         if( display ) disp_field(NULL, fp, s1, 1, 0);
         ndiff++;
      }

   return ndiff;
}


/*----------------------------------------------------------------------
 * return the number of fields that differ
 *----------------------------------------------------------------------*/
int diff_hdrs_list( nifti_1_header * s0, nifti_1_header * s1, str_list * slist,
                    int display )
{
   field_s  * fp;
   char    ** sptr;
   int        c, ndiff = 0;

   sptr = slist->list;
   for( c = 0; c < slist->len; c++ )
   {
      fp = get_hdr_field(*sptr, 1);    /* "not found" displayed in func */
      if( fp && diff_field(fp, s0, s1, 1) )
      {
         if( display ) disp_field(NULL, fp, s0, 1, ndiff == 0);
         if( display ) disp_field(NULL, fp, s1, 1, 0);
         ndiff++;
      }
      sptr++;
   }

   return ndiff;
}


/*----------------------------------------------------------------------
 * return the number of fields that differ
 *----------------------------------------------------------------------*/
int diff_nims_list( nifti_image * s0, nifti_image * s1, str_list * slist,
                    int display )
{
   field_s  * fp;
   char    ** sptr;
   int        c, ndiff = 0;

   sptr = slist->list;
   for( c = 0; c < slist->len; c++ )
   {
      fp = get_nim_field(*sptr, 1);    /* "not found" displayed in func */
      if( fp && diff_field(fp, s0, s1, 1) )
      {
         if( display ) disp_field(NULL, fp, s0, 1, ndiff == 0);
         if( display ) disp_field(NULL, fp, s1, 1, 0);
         ndiff++;
      }
      sptr++;
   }

   return ndiff;
}


/*----------------------------------------------------------------------
 * display data from collapsed_image
 *----------------------------------------------------------------------*/
int act_disp_ci( nt_opts * opts )
{
   nifti_image *  nim;
   void        *  data = NULL;
   char           space = ' ';  /* use space or newline */
   int            filenum, len, err;

   if( opts->dci_lines ) space = '\n';  /* then use newlines as separators */

   if( g_debug > 2 && opts->dts )
   {
      fprintf(stderr,"-d displaying time series at (i,j,k) = (%d,%d,%d)\n"
                     "      for %d nifti datasets...\n\n", opts->ci_dims[1],
              opts->ci_dims[2], opts->ci_dims[3], opts->infiles.len);
   }
   else if ( g_debug > 2 ) /* the general collapsed image form */
   {
      fprintf(stderr,"-d displaying collapsed image for %d datasets...\n\n"
                     "   dims = ", opts->infiles.len);
      disp_raw_data(opts->ci_dims, DT_INT32, 8, ' ', 1);
   }

   for( filenum = 0; filenum < opts->infiles.len; filenum++ )
   {
      err = 0;
      nim = nifti_image_read(opts->infiles.list[filenum], 0);
      if( !nim ) continue;  /* errors are printed from library */
      if( opts->dts && nim->ndim != 4 )
      {
         fprintf(stderr,"** error: dataset '%s' is not 4-dimensional\n",
                 nim->fname);
         err++;
      }
      
      switch( nim->datatype )
      {
         case DT_INT8:    case DT_INT16:   case DT_INT32:
         case DT_UINT8:   case DT_UINT16:  case DT_UINT32:
         case DT_FLOAT32: case DT_FLOAT64:
               if( g_debug > 1 )
                  fprintf(stderr,"-d datatype %d of size %d\n",
                          nim->datatype, nim->nbyper);
               break;
         default:
               fprintf(stderr,"** dataset '%s' has unknown type %d\n",
                       nim->fname, nim->datatype);
               err++;
               break;
      }

      if( err ) { nifti_image_free(nim);  continue; }
                                                                                
      len = nifti_read_collapsed_image(nim, opts->ci_dims, &data);
      if( len < 0 || !data )
      {
         fprintf(stderr,"** FAILURE for dataset '%s'\n", nim->fname);
         if( data ) free(data);
         err++;
      }
      else if( len != (nim->nt * nim->nbyper) )
      {
         fprintf(stderr,"** dset read '%s', returned length %d instead of %d\n",
                 nim->fname, len, nim->nt * nim->nbyper);
         free(data);  data = NULL;
         err++;
      }

      if( err ){ nifti_image_free(nim);  continue; }

      /* now just print the results */
      if( g_debug > 0 )
      {
         fprintf(stdout,"\ndataset '%s' @ (", nim->fname);
         if( opts->dts ) disp_raw_data(opts->ci_dims+1, DT_INT32, 3, ' ', 0);
         else            disp_raw_data(opts->ci_dims+1, DT_INT32, 7, ' ', 0);
         fprintf(stdout,")\n");
      }

      disp_raw_data(data, nim->datatype, len / nim->nbyper, space, 1);

      nifti_image_free(nim);
   }

   if( data ) free(data);

   return 0;
}


int disp_raw_data( void * data, int type, int nvals, char space, int newline )
{
   char * dp, fbuf[32];
   int    c, size;

   nifti_datatype_sizes( type, &size, NULL );   /* get nbyper */

   for( c = 0, dp = (char *)data; c < nvals; c++, dp += size )
   {
      switch( type )
      {
         case DT_INT8:
               printf("%d", *(char *)dp);
               break;
         case DT_INT16:
               printf("%d", *(short *)dp);
               break;
         case DT_INT32:
               printf("%d", *(int *)dp);
               break;
         case DT_UINT8:
               printf("%u", *(unsigned char *)dp);
               break;
         case DT_UINT16:
               printf("%u", *(unsigned short *)dp);
               break;
         case DT_UINT32:
               printf("%u", *(unsigned int *)dp);
               break;
         case DT_FLOAT32:
         {
               sprintf(fbuf,"%f", *(float *)dp);
               clear_float_zeros(fbuf);
               printf("%s", fbuf);
               break;
         }
         case DT_FLOAT64:
         {
               sprintf(fbuf,"%f", *(double *)dp);
               clear_float_zeros(fbuf);
               printf("%s", fbuf);
               break;
         }
         default:
               fprintf(stderr,"** disp_raw_data: unknown type %d\n", type);
               return 1;
      }
      if( c < nvals - 1 ) fputc(space,stdout);
   }

   if ( newline ) fputc('\n',stdout);

   return 0;
}

/*----------------------------------------------------------------------
 * remove trailing zeros from string of printed float
 * return  1 if something was cleared
 *         0 if not
 *----------------------------------------------------------------------*/
int clear_float_zeros( char * str )
{
   char * dp  = strchr(str, '.'), * valp;
   int    len;

   if( !dp ) return 0;      /* nothing to clear */

   len = strlen(dp);

   /* never clear what is just to the right of '.' */
   for( valp = dp+len-1; (valp > dp+1) && (*valp==' ' || *valp=='0'); valp-- )
       *valp = '\0';     /* clear, so we don't worry about break conditions */

   if( valp < dp + len - 1 ) return 1;
   return 0;
}


/*----------------------------------------------------------------------
 * create a new dataset using sub-brick selection
 *----------------------------------------------------------------------*/
int act_cbl( nt_opts * opts )
{
   nifti_brick_list   NBL;
   nifti_image      * nim;
   char             * fname, * selstr, * cp;
   int              * blist;
   int                err = 0;

   if( g_debug > 2 )
      fprintf(stderr,"-d copying file info from '%s' to '%s'\n",
              opts->infiles.list[0], opts->prefix);

   /* sanity checks */
   if( ! opts->prefix ) {
      fprintf(stderr,"** error: -prefix is required with -cbl function\n");
      return 1;
   } else if( opts->infiles.len > 1 ) {
      fprintf(stderr,"** sorry, at the moment -cbl allows only 1 input\n");
      return 1;
   }

   /* remove selector from fname, and copy selector string */
   fname = nifti_strdup(opts->infiles.list[0]);
   cp = strchr(fname,'[');  if( !cp )  cp = strchr(fname,'{');

   if( !cp ) {
      if( g_debug > 1 )
         fprintf(stderr,"-d using -cbl without brick list in '%s'\n",fname);
      selstr = nifti_strdup("[0..$]");
   } else {
      selstr = nifti_strdup(cp);
      *cp = '\0';    /* remove selection string from fname */
   }

   if( g_debug > 1 )
      fprintf(stderr,"+d -cbl: using '%s' for selection string\n", selstr);

   nim = nifti_image_read(fname, 0);  /* get image */
   if( !nim ) return 1;
      
   blist = nifti_get_intlist(nim->nt, selstr);
   nifti_image_free(nim);             /* throw away, will re-load */
   if( !blist ){
      fprintf(stderr,"** failed sub-brick selection using '%s'\n",selstr);
      free(fname);  free(selstr);  return 1;
   }

   nim = nifti_image_read_bricks(fname, blist[0], blist+1, &NBL);
   free(blist);  /* with this */
   if( !nim ){  free(fname);  free(selstr);  return 1; }

   if( g_debug > 1 ) fprintf(stderr,"+d sub-bricks loaded\n");

   /* add command as COMMENT extension */
   if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                          strlen(opts->command), NIFTI_ECODE_COMMENT) )
      fprintf(stderr,"** failed to add command to image as extension\n");

   /* replace filenames using prefix */
   if( nifti_set_filenames(nim, opts->prefix, 1, 1) )
   {
      fprintf(stderr,"** failed to set names, prefix = '%s'\n",opts->prefix);
      err++;
   }

   if(g_debug>2) disp_field("new nim:\n",g_nim_fields,nim,NT_NIM_NUM_FIELDS,1);

   /* and finally, write out results */
   if( err == 0 && nifti_nim_is_valid(nim, g_debug) )
      nifti_image_write_bricks(nim, &NBL);

   nifti_image_free(nim);
   nifti_free_NBL(&NBL);
   free(fname);
   free(selstr);

   return 0;
}


/*----------------------------------------------------------------------
 * create a new dataset using read_collapsed_image
 *----------------------------------------------------------------------*/
int act_cci( nt_opts * opts )
{
   nifti_image      * nim;
   int                c;

   if( g_debug > 2 )
      fprintf(stderr,"-d collapsing file info from '%s' to '%s'\n",
              opts->infiles.list[0], opts->prefix);

   /* sanity checks */
   if( ! opts->prefix ) {
      fprintf(stderr,"** error: -prefix is required with -cci function\n");
      return 1;
   } else if( opts->infiles.len > 1 ) {
      fprintf(stderr,"** sorry, at the moment -cci allows only 1 input\n");
      return 1;
   }

   nim = nifti_image_read(opts->infiles.list[0], 0);
   if( !nim ) return 1;
   nim->data = NULL;    /* just to be sure */
      
   if( nifti_read_collapsed_image(nim, opts->ci_dims, &nim->data) < 0 )
   {
      nifti_image_free(nim);
      return 1;
   }

   /* add command as COMMENT extension */
   if( opts->keep_hist && nifti_add_extension(nim, opts->command,
                          strlen(opts->command), NIFTI_ECODE_COMMENT) )
      fprintf(stderr,"** failed to add command to image as extension\n");

   /* replace filenames using prefix */
   if( nifti_set_filenames(nim, opts->prefix, 1, 1) )
   {
      fprintf(stderr,"** failed to set names, prefix = '%s'\n",opts->prefix);
      nifti_image_free(nim);
      return 1;
   }

   for( c = 1; c < 8; c++ )  /* nuke any collapsed dimension */
      if( opts->ci_dims[c] >= 0 ) nim->dim[c] = 1;

   nifti_update_dims_from_array(nim);

   if(g_debug>2) disp_field("new nim:\n",g_nim_fields,nim,NT_NIM_NUM_FIELDS,1);

   /* and finally, write out results */
   if( nifti_nim_is_valid(nim, g_debug) ) nifti_image_write(nim);

   nifti_image_free(nim);

   return 0;
}

