date and time created 82/08/30 09:57:37 by rrh

SCCS-vsn: old/cpp/yylex.c 1.1

diff --git a/usr/src/old/cpp/yylex.c b/usr/src/old/cpp/yylex.c
new file mode 100644 (file)
index 0000000..865addd
--- /dev/null
+++ b/usr/src/old/cpp/yylex.c
@@ -0,0 +1,90 @@
+#ifndef lint
+static char sccsid[] = "@(#)yylex.c 1.1 %G%";
+#endif lint
+
+#define isid(a)  ((fastab+COFF)[a]&IB)
+#define IB 1
+/*     #if '\377' < 0          it would be nice if this worked properly!!!!! */
+#if pdp11 | vax
+#define COFF 128
+#else
+#define COFF 0
+#endif
+
+yylex() {
+       static int ifdef=0;
+       static char *op2[]={"||",  "&&" , ">>", "<<", ">=", "<=", "!=", "=="};
+       static int  val2[]={OROR, ANDAND,  RS,   LS,   GE,   LE,   NE,   EQ};
+       static char *opc="b\bt\tn\nf\fr\r\\\\";
+       extern char fastab[];
+       extern char *outp,*inp,*newp; extern int flslvl;
+       register char savc, *s; char *skipbl(); int val;
+       register char **p2;
+       struct symtab {
+               char *name;
+               char *value;
+       } *sp, *lookup();
+
+for (;;) {
+       newp=skipbl(newp);
+       if (*inp=='\n') return(stop);   /* end of #if */
+       savc= *newp; *newp='\0';
+       for (p2=op2+8; --p2>=op2; )     /* check 2-char ops */
+               if (0==strcmp(*p2,inp)) {val=val2[p2-op2]; goto ret;}
+       s="+-*/%<>&^|?:!~(),";  /* check 1-char ops */
+       while (*s) if (*s++== *inp) {val= *--s; goto ret;}
+       if (*inp<='9' && *inp>='0') {/* a number */
+               if (*inp=='0') yylval= (inp[1]=='x' || inp[1]=='X') ?
+                       tobinary(inp+2,16) : tobinary(inp+1,8);
+               else yylval=tobinary(inp,10);
+               val=number;
+       } else if (isid(*inp)) {
+               if (0==strcmp(inp,"defined")) {ifdef=1; ++flslvl; val=DEFINED;}
+               else {
+                       sp=lookup(inp,-1); if (ifdef!=0) {ifdef=0; --flslvl;}
+                       yylval= (sp->value==0) ? 0 : 1;
+                       val=number;
+               }
+       } else  if (*inp=='\'') {/* character constant */
+               val=number;
+               if (inp[1]=='\\') {/* escaped */
+                       char c; if (newp[-1]=='\'') newp[-1]='\0';
+                       s=opc;
+                       while (*s) if (*s++!=inp[2]) ++s; else {yylval= *s; goto ret;}
+                       if (inp[2]<='9' && inp[2]>='0') yylval=c=tobinary(inp+2,8);
+                       else yylval=inp[2];
+               } else yylval=inp[1];
+       } else if (0==strcmp("\\\n",inp)) {*newp=savc; continue;}
+       else {
+               *newp=savc; pperror("Illegal character %c in preprocessor if", *inp);
+               continue;
+       }
+ret:
+       *newp=savc; outp=inp=newp; return(val);
+}
+}
+
+tobinary(st, b) char *st; {
+       int n, c, t;
+       char *s;
+       n=0;
+       s=st;
+       while (c = *s++) {
+       switch(c) {
+               case '0': case '1': case '2': case '3': case '4': 
+               case '5': case '6': case '7': case '8': case '9': 
+                       t = c-'0'; break;
+               case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': 
+                       t = c-'a'; if (b>10) break;
+               case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': 
+                       t = c - 'A'; if (b>10) break;
+               default:
+                       t = -1;
+                       if ( c=='l' || c=='L') if (*s=='\0') break;
+                       pperror("Illegal number %s", st);
+       }
+       if (t<0) break;
+       n = n*b+t;
+       }
+return(n);
+}