source: trunk/athena/bin/delete/shell_regexp.c @ 24908

/*
 * $Id: shell_regexp.c,v 1.4 1999-01-22 23:09:04 ghudson Exp $
 *
 * This program is part of a package including delete, undelete,
 * lsdel, expunge and purge.  The software suite is meant as a
 * replacement for rm which allows for file recovery.
 * 
 * Copyright (c) 1989 by the Massachusetts Institute of Technology.
 * For copying and distribution information, see the file "mit-copying.h."
 */

#include <com_err.h>
#include "shell_regexp.h"
#include "delete_errs.h"
#include "errors.h"
#include "mit-copying.h"
#include "util.h"

static int real_cmp();

/*
 * This is a simple pattern matcher that takes a pattern string and
 * another string (theoretically a filename) and checks if the second
 * string matches the pattern string using shell special characters
 * (i.e. it recognizes \, ?, *, [, ]).  It also special cases dot
 * files (i.e. * doesn't match files that start with periods, and
 * neither will ?*, and neither will [.]*).
 */

int reg_cmp(pattern, filename)
char *pattern, *filename;
{
     /* First, dot file special cases */
     if ((*filename == '.') && (*pattern != '.'))
          return REGEXP_NO_MATCH;

     return real_cmp(pattern, filename);
}

static int real_cmp(pattern, filename)
char *pattern, *filename;
{
     if (*pattern == '\0') {
          if (*filename == '\0')
               return REGEXP_MATCH;
          else
               return REGEXP_NO_MATCH;
     }
     
     if (*pattern == '*') {
          int retval;
          char *ptr;
          
          if (*(pattern + 1) == '\0')
               /* asterisk by itself matches anything */
               return REGEXP_MATCH;
          for (ptr = filename; *ptr; ptr++)
               if ((retval = real_cmp(pattern + 1, ptr)) != REGEXP_NO_MATCH)
                    return retval;
          return REGEXP_NO_MATCH;
     }

     if (*filename == '\0')
          return REGEXP_NO_MATCH;
     
     if (*pattern == '?')
          return real_cmp(pattern + 1, filename + 1);

     if (*pattern == '\\') {
          if (*(pattern + 1) == '\0') {
               set_error(REGEXP_MISSING_QUOTED_CHAR);
               return -1;
          }
          if (*(pattern + 1) == *filename)
               return real_cmp(pattern + 2, filename + 1);
          else
               return REGEXP_NO_MATCH;
     }

     if (*pattern == '[') {
          char *ptr, *end_ptr;

          for (end_ptr = pattern + 1; (*end_ptr != '\0') && (*end_ptr != ']');
               end_ptr++) ;
          if (*end_ptr == '\0') {
               set_error(REGEXP_MISSING_BRACE);
               return -1;
          }
          if (end_ptr == pattern + 1) {
               set_error(REGEXP_EMPTY_BRACES);
               return -1;
          }
          for (ptr = pattern + 1; ptr < end_ptr; ptr++) {
               if ((*(ptr + 1) == '-') && (*(ptr + 2) != ']')) {
                    if ((*ptr <= *filename) && (*(ptr + 2) >= *filename))
                         return real_cmp(end_ptr + 1, filename + 1);
                    else {
                         ptr += 2;
                         continue;
                    }
               }
               if (*ptr == *filename)
                    return real_cmp(end_ptr + 1, filename + 1);
          }

          return REGEXP_NO_MATCH;
     }
                    
     if (*pattern == *filename)
          return real_cmp(pattern + 1, filename + 1);
     else
          return REGEXP_NO_MATCH;
}