UNIX 7th Ed. - /usr/src/cmd/cpp/yylex.c

   1: #define isid(a)  ((fastab+COFF)[a]&IB)
   2: #define IB 1
   3: /*	#if '\377' < 0		it would be nice if this worked properly!!!!! */
   4: #if pdp11 | vax
   5: #define COFF 128
   6: #else
   7: #define COFF 0
   8: #endif
   9: 
  10: yylex() {
  11:     static int ifdef=0;
  12:     static char *op2[]={"||",  "&&" , ">>", "<<", ">=", "<=", "!=", "=="};
  13:     static int  val2[]={OROR, ANDAND,  RS,   LS,   GE,   LE,   NE,   EQ};
  14:     static char *opc="b\bt\tn\nf\fr\r\\\\";
  15:     extern char fastab[];
  16:     extern char *outp,*inp,*newp; extern int flslvl;
  17:     register char savc, *s; char *skipbl(); int val;
  18:     register char **p2;
  19:     struct symtab {
  20:         char *name;
  21:         char *value;
  22:     } *sp;
  23: 
  24: for (;;) {
  25:     newp=skipbl(newp);
  26:     if (*inp=='\n') return(stop);   /* end of #if */
  27:     savc= *newp; *newp='\0';
  28:     for (p2=op2+8; --p2>=op2; ) /* check 2-char ops */
  29:         if (0==strcmp(*p2,inp)) {val=val2[p2-op2]; goto ret;}
  30:     s="+-*/%<>&^|?:!~(),";  /* check 1-char ops */
  31:     while (*s) if (*s++== *inp) {val= *--s; goto ret;}
  32:     if (*inp<='9' && *inp>='0') {/* a number */
  33:         if (*inp=='0') yylval= (inp[1]=='x' || inp[1]=='X') ?
  34:             tobinary(inp+2,16) : tobinary(inp+1,8);
  35:         else yylval=tobinary(inp,10);
  36:         val=number;
  37:     } else if (isid(*inp)) {
  38:         if (0==strcmp(inp,"defined")) {ifdef=1; ++flslvl; val=DEFINED;}
  39:         else {
  40:             sp=lookup(inp,-1); if (ifdef!=0) {ifdef=0; --flslvl;}
  41:             yylval= (sp->value==0) ? 0 : 1;
  42:             val=number;
  43:         }
  44:     } else  if (*inp=='\'') {/* character constant */
  45:         val=number;
  46:         if (inp[1]=='\\') {/* escaped */
  47:             char c; if (newp[-1]=='\'') newp[-1]='\0';
  48:             s=opc;
  49:             while (*s) if (*s++!=inp[2]) ++s; else {yylval= *s; goto ret;}
  50:             if (inp[2]<='9' && inp[2]>='0') yylval=c=tobinary(inp+2,8);
  51:             else yylval=inp[2];
  52:         } else yylval=inp[1];
  53:     } else if (0==strcmp("\\\n",inp)) {*newp=savc; continue;}
  54:     else {
  55:         *newp=savc; pperror("Illegal character %c in preprocessor if", *inp);
  56:         continue;
  57:     }
  58: ret:
  59:     *newp=savc; outp=inp=newp; return(val);
  60: }
  61: }
  62: 
  63: tobinary(st, b) char *st; {
  64:     int n, c, t;
  65:     char *s;
  66:     n=0;
  67:     s=st;
  68:     while (c = *s++) {
  69:     switch(c) {
  70:         case '0': case '1': case '2': case '3': case '4':
  71:         case '5': case '6': case '7': case '8': case '9':
  72:             t = c-'0'; break;
  73:         case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
  74:             t = c-'a'; if (b>10) break;
  75:         case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
  76:             t = c - 'A'; if (b>10) break;
  77:         default:
  78:             t = -1;
  79:             if ( c=='l' || c=='L') if (*s=='\0') break;
  80:             pperror("Illegal number %s", st);
  81:     }
  82:     if (t<0) break;
  83:     n = n*b+t;
  84:     }
  85: return(n);
  86: }

Defined functions

Defined struct's

Defined macros

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