newlib/libc/stdio/sccl.c

   1 /*-
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * and/or other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  */
  17
  18 /* Split from vfscanf.c  */
  19
  20 #include <_ansi.h>
  21 #include <reent.h>
  22 #include <newlib.h>
  23 #include <stdio.h>
  24 #include "local.h"
  25
  26 /*
  27  * Fill in the given table from the scanset at the given format
  28  * (just after `[').  Return a pointer to the character past the
  29  * closing `]'.  The table has a 1 wherever characters should be
  30  * considered part of the scanset.
  31  */
  32
  33 u_char *
  34 __sccl (register char *tab,
  35        register u_char *fmt)
  36 {
  37   register int c, n, v;
  38
  39   /* first `clear' the whole table */
  40   c = *fmt++;                   /* first char hat => negated scanset */
  41   if (c == '^')
  42     {
  43       v = 1;                    /* default => accept */
  44       c = *fmt++;               /* get new first char */
  45     }
  46   else
  47     v = 0;                      /* default => reject */
  48   /* should probably use memset here */
  49   for (n = 0; n < 256; n++)
  50     tab[n] = v;
  51   if (c == 0)
  52     return fmt - 1;             /* format ended before closing ] */
  53
  54   /*
  55    * Now set the entries corresponding to the actual scanset to the
  56    * opposite of the above.
  57    *
  58    * The first character may be ']' (or '-') without being special; the
  59    * last character may be '-'.
  60    */
  61
  62   v = 1 - v;
  63   for (;;)
  64     {
  65       tab[c] = v;               /* take character c */
  66     doswitch:
  67       n = *fmt++;               /* and examine the next */
  68       switch (n)
  69         {
  70
  71         case 0:         /* format ended too soon */
  72           return fmt - 1;
  73
  74         case '-':
  75           /*
  76            * A scanset of the form [01+-] is defined as `the digit 0, the
  77            * digit 1, the character +, the character -', but the effect of a
  78            * scanset such as [a-zA-Z0-9] is implementation defined.  The V7
  79            * Unix scanf treats `a-z' as `the letters a through z', but treats
  80            * `a-a' as `the letter a, the character -, and the letter a'.
  81            *
  82            * For compatibility, the `-' is not considerd to define a range if
  83            * the character following it is either a close bracket (required by
  84            * ANSI) or is not numerically greater than the character we just
  85            * stored in the table (c).
  86            */
  87           n = *fmt;
  88           if (n == ']' || n < c)
  89             {
  90               c = '-';
  91               break;            /* resume the for(;;) */
  92             }
  93           fmt++;
  94           do
  95             {                   /* fill in the range */
  96               tab[++c] = v;
  97             }
  98           while (c < n);
  99 #if 1                   /* XXX another disgusting compatibility hack */
 100           /*
 101            * Alas, the V7 Unix scanf also treats formats such
 102            * as [a-c-e] as `the letters a through e'. This too
 103            * is permitted by the standard....
 104            */
 105           goto doswitch;
 106 #else
 107           c = *fmt++;
 108           if (c == 0)
 109             return fmt - 1;
 110           if (c == ']')
 111             return fmt;
 112 #endif
 113
 114           break;
 115
 116
 117         case ']':               /* end of scanset */
 118           return fmt;
 119
 120         default:                /* just another character */
 121           c = n;
 122           break;
 123         }
 124     }
 125   /* NOTREACHED */
 126 }