util/cpp/skip.c

   1 /*
   2  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
   3  * See the copyright notice in the ACK home directory, in the file "Copyright".
   4  */
   5 /* $Id: skip.c,v 1.6 1994/06/24 10:19:03 ceriel Exp $ */
   6 /* PREPROCESSOR: INPUT SKIP FUNCTIONS */
   7
   8 #include        "LLlex.h"
   9 #include        "class.h"
  10 #include        "input.h"
  11
  12 int
  13 skipspaces(ch, skipnl)
  14         register int ch;
  15 {
  16         /*      skipspaces() skips any white space and returns the first
  17                 non-space character.
  18         */
  19         register int nlseen = 0;
  20
  21         for (;;) {
  22                 while (class(ch) == STSKIP) {
  23                         nlseen = 0;
  24                         LoadChar(ch);
  25                 }
  26                 if (skipnl && class(ch) == STNL) {
  27                         LoadChar(ch);
  28                         ++LineNumber;
  29                         nlseen++;
  30                         continue;
  31                 }
  32                 /* How about "\\\n"?????????    */
  33                 if (ch == '/') {
  34                         LoadChar(ch);
  35                         if (ch == '*') {
  36                                 skipcomment();
  37                                 LoadChar(ch);
  38                         }
  39                         else    {
  40                                 PushBack();
  41                                 return '/';
  42                         }
  43                 }
  44                 else if (nlseen && ch == '#') {
  45                         domacro();
  46                         LoadChar(ch);
  47                         /* ch is the first character of a line. This means
  48                          * that nlseen will still be true.
  49                          */
  50                 } else
  51                         return ch;
  52         }
  53 }
  54
  55 skipline()
  56 {
  57         /*      skipline() skips all characters until a newline character
  58                 is seen, not escaped by a '\\'.
  59                 Any comment is skipped.
  60         */
  61         register int c;
  62
  63         LoadChar(c);
  64         while (class(c) != STNL && c != EOI) {
  65                 if (class(c) == STSTR || class(c) == STCHAR) {
  66                         register int stopc = c;
  67                         int escaped;
  68                         do {
  69                                 escaped = 0;
  70                                 LoadChar(c);
  71                                 if (class(c) == STNL || c == EOI) {
  72                                         break;
  73                                 }
  74                                 if (c == '\\') {
  75                                         LoadChar(c);
  76                                         if (c == '\n') {
  77                                                 ++LineNumber;
  78                                         }
  79                                         else escaped = 1;
  80                                 }
  81                         } while (escaped || c != stopc);
  82                         if (class(c) != STNL && c != EOI) {
  83                                 LoadChar(c);
  84                         }
  85                         continue;
  86                 }
  87                 if (c == '\\') {
  88                         LoadChar(c);
  89                         if (class(c) == STNL)
  90                                 ++LineNumber;
  91                 }
  92                 if (c == '/') {
  93                         LoadChar(c);
  94                         if (c == '*')
  95                                 skipcomment();
  96                         else
  97                                 continue;
  98                 }
  99                 LoadChar(c);
 100         }
 101         ++LineNumber;
 102         if (c == EOI) {         /* garbage input...             */
 103                 error("unexpected EOF while skipping text");
 104                 PushBack();
 105         }
 106 }