1 #include <sys/cdefs.h>
2
3 __SCCSID("@(#)yylex.c 1.4 10/15/86");
4 __RCSID("$MirOS: src/libexec/cpp/yylex.c,v 1.4 2008/11/22 13:06:44 tg Exp $");
5
6 #define isid(a) ((fastab+COFF)[a]&IB)
7 #define IB 1
8 /* #if '\377' < 0 it would be nice if this worked properly!!!!! */
9 #if pdp11 | vax | mc68000 | tahoe
10 #define COFF 128
11 #else
12 #define COFF 0
13 #endif
14
yylex()15 yylex() {
16 static int ifdef=0;
17 static char *op2[]={"||", "&&" , ">>", "<<", ">=", "<=", "!=", "=="};
18 static int val2[]={OROR, ANDAND, RS, LS, GE, LE, NE, EQ};
19 static char *opc="b\bt\tn\nf\fr\r\\\\";
20 extern char fastab[];
21 extern char *outp,*inp,*newp; extern int flslvl;
22 register char savc, *s; char *skipbl(); int val;
23 register char **p2;
24 struct symtab {
25 char *name;
26 char *value;
27 } *sp, *lookup();
28
29 for (;;) {
30 extern int passcom; /* this crap makes #if's work */
31 int opt_passcom = passcom; /* even with -C option */
32 passcom = 0; /* (else comments make syntax errs) */
33 newp=skipbl(newp);
34 passcom = opt_passcom; /* nb: lint uses -C so its useful! */
35 if (*inp=='\n') return(stop); /* end of #if */
36 savc= *newp; *newp='\0';
37 for (p2=op2+8; --p2>=op2; ) /* check 2-char ops */
38 if (0==strcmp(*p2,inp)) {val=val2[p2-op2]; goto ret;}
39 s="+-*/%<>&^|?:!~(),"; /* check 1-char ops */
40 while (*s) if (*s++== *inp) {val= *--s; goto ret;}
41 if (*inp<='9' && *inp>='0') {/* a number */
42 if (*inp=='0') yylval= (inp[1]=='x' || inp[1]=='X') ?
43 tobinary(inp+2,16) : tobinary(inp+1,8);
44 else yylval=tobinary(inp,10);
45 val=number;
46 } else if (isid(*inp)) {
47 if (0==strcmp(inp,"defined")) {ifdef=1; ++flslvl; val=DEFINED;}
48 else {
49 sp=lookup(inp,-1); if (ifdef!=0) {ifdef=0; --flslvl;}
50 yylval= (sp->value==0) ? 0 : 1;
51 val=number;
52 }
53 } else if (*inp=='\'') {/* character constant */
54 val=number;
55 if (inp[1]=='\\') {/* escaped */
56 char c; if (newp[-1]=='\'') newp[-1]='\0';
57 s=opc;
58 while (*s) if (*s++!=inp[2]) ++s; else {yylval= *s; goto ret;}
59 if (inp[2]<='9' && inp[2]>='0') yylval=c=tobinary(inp+2,8);
60 else yylval=inp[2];
61 } else yylval=inp[1];
62 } else if (0==strcmp("\\\n",inp)) {*newp=savc; continue;}
63 else {
64 *newp=savc; pperror("Illegal character %c in preprocessor if", *inp);
65 continue;
66 }
67 ret:
68 *newp=savc; outp=inp=newp; return(val);
69 }
70 }
71
tobinary(st,b)72 tobinary(st, b) char *st; {
73 int n, c, t;
74 char *s;
75 n=0;
76 s=st;
77 while (c = *s++) {
78 switch(c) {
79 case '0': case '1': case '2': case '3': case '4':
80 case '5': case '6': case '7': case '8': case '9':
81 t = c-'0'; break;
82 case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
83 t = c-'a'+10; if (b>10) break;
84 case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
85 t = c - 'A'+10; if (b>10) break;
86 default:
87 t = -1;
88 if ( c=='l' || c=='L') if (*s=='\0') break;
89 pperror("Illegal number %s", st);
90 }
91 if (t<0) break;
92 n = n*b+t;
93 }
94 return(n);
95 }
96