#include <assert.h>

#define  FMAX  2        /* Number of different filename patterns */

#include <osbind.h>
#include <stdio.h>

void fcbpath (struct _dta *, char *, char *);

/*
nextfile() returns the name of the next source file matching a filespec.

INPUT
   what: A flag specifying what to do.  If "what" is 0, nextfile()
      initializes itself.  If "what" is 1, nextfile() returns the next
      matching filename.
   filespec:  The filespec, usually containing wildcard characters, that
      specifies which files are needed.  If "what" is 0, filespec must be
      the filespec for which matching filenames are needed.  If "what" is 1,
      nextfile() does not use "filespec" and "filespec" should be NULL to
      avoid an assertion error during debugging.
   fileset:  nextfile() can keep track of more than one set of filespecs.
      The fileset specifies which filespec is being matched and therefore
      which set of files is being considered.  "fileset" can be in the
      range 0:FMAX.  Initialization of one fileset does not affect the
      other filesets.

OUTPUT
   IF what == 0 THEN
      return value is NULL
   ELSE IF what == 1 THEN
      IF a matching filename is found THEN
         return value is pointer to matching filename including supplied path
      ELSE
         IF at least one file matched previously but no more match THEN
            return value is NULL
         ELSE IF supplied filespec never matched any filename THEN
            IF this is the first call with what == 1 THEN
               return value is pointer to original filespec
            ELSE
               return value is NULL
            END IF
         END IF
      END IF
   END IF

NOTE

   Initialization done when "what"=0 is not dependent on the correctness
   of the supplied filespec but simply initializes internal variables
   and makes a local copy of the supplied filespec.  If the supplied
   filespec was illegal, the only effect is that the first time that
   nextfile() is called with "what"=1, it will return the original
   filespec instead of a matching filename.  That the filespec was
   illegal will become obvious when the caller attempts to open the
   returned filename for input/output and the open attempt fails.

USAGE HINTS

nextfile() can be used in the following manner:

      char *filespec;                  -- will point to filespec
      char *this_file;                 -- will point to matching filename
      filespec = parse_command_line(); -- may contain wildcards
      FILE *stream;

      nextfile (0, filespec, 0);          -- initialize fileset 0
      while ((this_file = nextfile(1, (char *) NULL, 0)) != NULL) {
         stream = fopen (this_file, "whatever");
         if (stream == NULL)
            printf ("could not open %s\n", this_file);
         else
            perform_operations (stream);
      }
*/

char *nextfile (what, filespec, fileset)
int what;                        /* whether to initialize or match      */
register char *filespec;         /* filespec to match if initializing   */
register int fileset;            /* which set of files                  */
{
	static struct _dta new_dta [FMAX+1];     /* our own private dta        */
	static int first_time [FMAX+1];
											/* holds a pathname to return */
	static char pathholder [FMAX+1][FILENAME_MAX];
											/* our own copy of filespec   */
	static char saved_fspec [FMAX+1][FILENAME_MAX];
	static done;

   assert(fileset >= 0 && fileset <= FMAX);
   if (what == 0) {
      assert(filespec != NULL);
      strcpy (saved_fspec[fileset], filespec);  /* save the filespec */
      first_time[fileset] = 1;
      return ((char *) NULL);
   }

   Fsetdta (&new_dta[fileset]);   /* set new dta -- our very own */
   assert(what == 1);
   assert(filespec == NULL);
   assert(first_time[fileset] == 0 || first_time[fileset] == 1);

   if (first_time[fileset])            /* first time -- initialize etc. */
	   /* find first matching file */
	   done = Fsfirst(saved_fspec[fileset], 0);
   else
	   /* find next matching file */
	   done = Fsnext();

   if (done) {                         /* if error status                  */
      if (first_time[fileset]) {       /*   if file never matched then     */
         first_time[fileset] = 0;
         return (saved_fspec[fileset]);/*      return original filespec    */
      } else {                         /*   else                           */
         first_time[fileset] = 0;      /*                                  */
         return ((char *) NULL);         /*      return (NULL) for no more   */
      }
   } else {                                        /* a file matched */
      first_time[fileset] = 0;
      /* add path info  */
      fcbpath (&new_dta[fileset], saved_fspec[fileset], pathholder[fileset]);
      return (pathholder[fileset]);                /* matching path  */
   }
} /* nextfile */



/*
fcbpath() accepts a pointer to the Disk Transfer Area, a character
pointer to a pathname that may contain wildcards, and a character
pointer to a buffer.  It copies into the buffer the path prefix from
the pathname and the filename prefix from the DTA so that it forms a
complete path.
*/

void fcbpath (dta, old_path, new_path)
struct _dta *dta;
char *old_path;
register char *new_path;
{
   register int i;
   int length, start_pos;

   strcpy(new_path, old_path);               /* copy the whole thing first */
   length = strlen(new_path);
   i = length - 1;                           /* i points to end of path */
   while (i >= 0 && new_path[i] != '/' && new_path[i] != '\\' && new_path[i] != ':')
      i--;
   /* either we found a "/", "\", or ":", or we reached the beginning of
      the name.  In any case, i points to the last character of the
      path part. */
   start_pos = i + 1;
   for (i = 0; i < 13; i++)
      new_path[start_pos+i] = dta->dta_name[i];
   new_path[start_pos+13] = '\0';
}