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