compiler/stdc/stpsym.c

   1 /*
   2     Copyright © 2002-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     SAS/C function stpsym().
   6 */
   7
   8 #include <ctype.h>
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <string.h>
  14
  15         char * stpsym (
  16
  17 /*  SYNOPSIS */
  18         char * str_ptr,
  19         char * dest_ptr,
  20         int dest_size)
  21
  22 /*  FUNCTION
  23         Searches for a symbol in a string.
  24
  25     INPUTS
  26         str_ptr - points to the string to scan
  27
  28         dest_ptr - points to the string where stpsym stores the symbol
  29
  30         dest_size - specifies the size in bytes of *dest_ptr
  31
  32     RESULT
  33         Pointer to the next character in the string after the symbol.
  34         If stpsym could not find a symbol, it returns str_ptr.
  35
  36     NOTES
  37         A symbol consists of an alphabetic character followed by zero
  38         or more alphanumeric characters.  stpsym() does not skip leading
  39         space characters.
  40
  41         Note that if you want to retrieve a symbol of length n, you need
  42         to ensure that *dest_ptr can accommodate at least n+1 elements,
  43         and that dest_size == n+1.  This extra element is needed for the
  44         terminating null character.
  45
  46     EXAMPLE
  47         #include <string.h>
  48         #include <stdio.h>
  49
  50         int main(void)
  51         {
  52             char *text;
  53             char symbol[10];
  54             char *r;
  55
  56             text = "alpha1  2";
  57             r = stpsym(text,symbol,10);
  58             printf("%s",symbol);   // prints "alpha1"
  59         }
  60
  61     BUGS
  62
  63     SEE ALSO
  64
  65     INTERNALS
  66
  67 ******************************************************************************/
  68 {
  69     int count = 0;
  70     char *str = str_ptr;
  71
  72     if(str == NULL)
  73         return NULL;
  74
  75     if(isalpha(*str))
  76     {
  77         dest_ptr[count++] = *str++;
  78         while(isalnum(*str) && count<(dest_size-1))
  79         {
  80             dest_ptr[count++] = *str++;
  81         }
  82         dest_ptr[count] = 0;
  83     }
  84
  85     return str;
  86 } /* stpsym */