compilers/linux86-0.16.17/libc/misc/getopt.c

   1
   2 /*
   3  * From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) Newsgroups: net.sources
   4  * Subject: getopt library routine Date: 30 Mar 85 04:45:33 GMT
   5  */
   6 /*
   7  * getopt -- public domain version of standard System V routine
   8  *
   9  * Strictly enforces the System V Command Syntax Standard; provided by D A
  10  * Gwyn of BRL for generic ANSI C implementations
  11  *
  12  * #define STRICT to prevent acceptance of clustered options with arguments
  13  * and ommision of whitespace between option and arg.
  14  */
  15
  16 #include <stdio.h>
  17 #include <string.h>
  18
  19 int   opterr = 1;               /* error => print message */
  20 int   optind = 1;               /* next argv[] index */
  21 char *optarg = NULL;            /* option parameter if any */
  22
  23 static int
  24 Err(name, mess, c)              /* returns '?' */
  25 char *name;                     /* program name argv[0] */
  26 char *mess;                     /* specific message */
  27 int   c;                        /* defective option letter */
  28 {
  29    if (opterr)
  30    {
  31       (void) fprintf(stderr,
  32                      "%s: %s -- %c\n",
  33                      name, mess, c
  34           );
  35    }
  36
  37    return '?';                  /* erroneous-option marker */
  38 }
  39
  40 int
  41 getopt(argc, argv, optstring)   /* returns letter, '?', EOF */
  42 int   argc;                     /* argument count from main */
  43 char *argv[];                   /* argument vector from main */
  44 char *optstring;                /* allowed args, e.g. "ab:c" */
  45 {
  46    static int sp = 1;           /* position within argument */
  47    register int osp;            /* saved `sp' for param test */
  48 #ifndef STRICT
  49    register int oind;           /* saved `optind' for param test */
  50 #endif
  51    register int c;              /* option letter */
  52    register char *cp;           /* -> option in `optstring' */
  53
  54    optarg = NULL;
  55
  56    if (sp == 1)                 /* fresh argument */
  57       if (optind >= argc        /* no more arguments */
  58           || argv[optind][0] != '-'     /* no more options */
  59           || argv[optind][1] == '\0'    /* not option; stdin */
  60           )
  61          return EOF;
  62       else if (strcmp(argv[optind], "--") == 0)
  63       {
  64          ++optind;              /* skip over "--" */
  65          return EOF;            /* "--" marks end of options */
  66       }
  67
  68    c = argv[optind][sp];        /* option letter */
  69    osp = sp++;                  /* get ready for next letter */
  70
  71 #ifndef STRICT
  72    oind = optind;               /* save optind for param test */
  73 #endif
  74    if (argv[optind][sp] == '\0')/* end of argument */
  75    {
  76       ++optind;                 /* get ready for next try */
  77       sp = 1;                   /* beginning of next argument */
  78    }
  79
  80    if (c == ':' || c == '?'     /* optstring syntax conflict */
  81        || (cp = strchr(optstring, c)) == NULL   /* not found */
  82        )
  83       return Err(argv[0], "illegal option", c);
  84
  85    if (cp[1] == ':')            /* option takes parameter */
  86    {
  87 #ifdef STRICT
  88       if (osp != 1)
  89          return Err(argv[0],
  90                     "option must not be clustered",
  91                     c
  92              );
  93
  94       if (sp != 1)              /* reset by end of argument */
  95          return Err(argv[0],
  96                     "option must be followed by white space",
  97                     c
  98              );
  99
 100 #else
 101       if (oind == optind)       /* argument w/o whitespace */
 102       {
 103          optarg = &argv[optind][sp];
 104          sp = 1;                /* beginning of next argument */
 105       }
 106
 107       else
 108 #endif
 109       if (optind >= argc)
 110          return Err(argv[0],
 111                     "option requires an argument",
 112                     c
 113              );
 114
 115       else                      /* argument w/ whitespace */
 116          optarg = argv[optind];
 117
 118       ++optind;                 /* skip over parameter */
 119    }
 120
 121    return c;
 122 }