externals/figlet/getopt.c

   1 /*
   2  * *    @(#)getopt.c    2.3 (smail) 5/30/87
   3  */
   4
   5 /*
   6  * Here's something you've all been waiting for:  the AT&T public domain
   7  * source for getopt(3).  It is the code which was given out at the 1985
   8  * UNIFORUM conference in Dallas. I obtained it by electronic mail directly
   9  * from AT&T.  The people there assure me that it is indeed in the public
  10  * domain.
  11  *
  12  * There is no manual page. That is because the one they gave out at UNIFORUM
  13  * was slightly different from the current System V Release 2 manual page.
  14  * The difference apparently involved a note about the famous rules 5 and 6,
  15  * recommending using white space between an option and its first argument,
  16  * and not grouping options that have arguments. Getopt itself is currently
  17  * lenient about both of these things White space is allowed, but not
  18  * mandatory, and the last option in a group can have an argument.  That
  19  * particular version of the man page evidently has no official existence,
  20  * and my source at AT&T did not send a copy. The current SVR2 man page
  21  * reflects the actual behavior of this getopt. However, I am not about to
  22  * post a copy of anything licensed by AT&T.
  23  */
  24
  25 #ifdef BSD
  26  #include <strings.h>
  27 #else
  28  #define index strchr
  29  #include <string.h>
  30 #endif
  31
  32 /* LINTLIBRARY */
  33 #ifndef NULL
  34 #define NULL    0
  35 #endif
  36
  37 #define EOF    (-1)
  38 #define ERR(s, c)    if(opterr){\
  39     extern int write(int, void *, unsigned);\
  40     char errbuf[2];\
  41     errbuf[0] = (char)c; errbuf[1] = '\n';\
  42     (void) write(2, strlwr(argv[0]), (unsigned)strlen(argv[0]));\
  43     (void) write(2, s, (unsigned)strlen(s));\
  44     (void) write(2, errbuf, 2);}
  45
  46 extern char    *index();
  47
  48 int             opterr = 1;
  49 int             optind = 1;
  50 int             optopt;
  51 char           *optarg;
  52
  53 int getopt(int argc, char *argv[], char *opts)
  54 {
  55       static int      sp = 1;
  56       register int    c;
  57       register char  *cp;
  58
  59       if (sp == 1)
  60       {
  61             if (optind >= argc || argv[optind][0] != '-' ||
  62                   argv[optind][1] == '\0')
  63                         return (EOF);
  64             else if (strcmp(argv[optind], "--") == 0)
  65             {
  66                   optind++;
  67                   return (EOF);
  68             }
  69       }
  70       optopt = c = argv[optind][sp];
  71       if (c == ':' || (cp = index(opts, c)) == NULL)
  72       {
  73             ERR(": illegal option -- ", c);
  74             if (argv[optind][++sp] == '\0')
  75             {
  76                   optind++;
  77                   sp = 1;
  78             }
  79             return ('?');
  80       }
  81       if (*++cp == ':')
  82       {
  83             if (argv[optind][sp + 1] != '\0')
  84                   optarg = &argv[optind++][sp + 1];
  85             else if (++optind >= argc)
  86             {
  87                   ERR(": option requires an argument -- ", c);
  88                   sp = 1;
  89                   return ('?');
  90             }
  91             else  optarg = argv[optind++];
  92             sp = 1;
  93       }
  94       else
  95       {
  96             if (argv[optind][++sp] == '\0')
  97             {
  98                   sp = 1;
  99                   optind++;
 100             }
 101             optarg = NULL;
 102       }
 103       return (c);
 104 }