lex.c

LCC4.2 C编译器源码

#include "c.h"
#include <float.h>
#include <errno.h>

static char rcsid[] = "$Id: lex.c,v 1.1 2002/08/28 23:12:44 drh Exp $";

#define MAXTOKEN 32

enum { BLANK=01,  NEWLINE=02, LETTER=04,
       DIGIT=010, HEX=020,    OTHER=040 };

static unsigned char map[256] = { /* 000 nul */	0,
				   /* 001 soh */	0,
				   /* 002 stx */	0,
				   /* 003 etx */	0,
				   /* 004 eot */	0,
				   /* 005 enq */	0,
				   /* 006 ack */	0,
				   /* 007 bel */	0,
				   /* 010 bs  */	0,
				   /* 011 ht  */	BLANK,
				   /* 012 nl  */	NEWLINE,
				   /* 013 vt  */	BLANK,
				   /* 014 ff  */	BLANK,
				   /* 015 cr  */	0,
				   /* 016 so  */	0,
				   /* 017 si  */	0,
				   /* 020 dle */	0,
				   /* 021 dc1 */	0,
				   /* 022 dc2 */	0,
				   /* 023 dc3 */	0,
				   /* 024 dc4 */	0,
				   /* 025 nak */	0,
				   /* 026 syn */	0,
				   /* 027 etb */	0,
				   /* 030 can */	0,
				   /* 031 em  */	0,
				   /* 032 sub */	0,
				   /* 033 esc */	0,
				   /* 034 fs  */	0,
				   /* 035 gs  */	0,
				   /* 036 rs  */	0,
				   /* 037 us  */	0,
				   /* 040 sp  */	BLANK,
				   /* 041 !   */	OTHER,
				   /* 042 "   */	OTHER,
				   /* 043 #   */	OTHER,
				   /* 044 $   */	0,
				   /* 045 %   */	OTHER,
				   /* 046 &   */	OTHER,
				   /* 047 '   */	OTHER,
				   /* 050 (   */	OTHER,
				   /* 051 )   */	OTHER,
				   /* 052 *   */	OTHER,
				   /* 053 +   */	OTHER,
				   /* 054 ,   */	OTHER,
				   /* 055 -   */	OTHER,
				   /* 056 .   */	OTHER,
				   /* 057 /   */	OTHER,
				   /* 060 0   */	DIGIT,
				   /* 061 1   */	DIGIT,
				   /* 062 2   */	DIGIT,
				   /* 063 3   */	DIGIT,
				   /* 064 4   */	DIGIT,
				   /* 065 5   */	DIGIT,
				   /* 066 6   */	DIGIT,
				   /* 067 7   */	DIGIT,
				   /* 070 8   */	DIGIT,
				   /* 071 9   */	DIGIT,
				   /* 072 :   */	OTHER,
				   /* 073 ;   */	OTHER,
				   /* 074 <   */	OTHER,
				   /* 075 =   */	OTHER,
				   /* 076 >   */	OTHER,
				   /* 077 ?   */	OTHER,
				   /* 100 @   */	0,
				   /* 101 A   */	LETTER|HEX,
				   /* 102 B   */	LETTER|HEX,
				   /* 103 C   */	LETTER|HEX,
				   /* 104 D   */	LETTER|HEX,
				   /* 105 E   */	LETTER|HEX,
				   /* 106 F   */	LETTER|HEX,
				   /* 107 G   */	LETTER,
				   /* 110 H   */	LETTER,
				   /* 111 I   */	LETTER,
				   /* 112 J   */	LETTER,
				   /* 113 K   */	LETTER,
				   /* 114 L   */	LETTER,
				   /* 115 M   */	LETTER,
				   /* 116 N   */	LETTER,
				   /* 117 O   */	LETTER,
				   /* 120 P   */	LETTER,
				   /* 121 Q   */	LETTER,
				   /* 122 R   */	LETTER,
				   /* 123 S   */	LETTER,
				   /* 124 T   */	LETTER,
				   /* 125 U   */	LETTER,
				   /* 126 V   */	LETTER,
				   /* 127 W   */	LETTER,
				   /* 130 X   */	LETTER,
				   /* 131 Y   */	LETTER,
				   /* 132 Z   */	LETTER,
				   /* 133 [   */	OTHER,
				   /* 134 \   */	OTHER,
				   /* 135 ]   */	OTHER,
				   /* 136 ^   */	OTHER,
				   /* 137 _   */	LETTER,
				   /* 140 `   */	0,
				   /* 141 a   */	LETTER|HEX,
				   /* 142 b   */	LETTER|HEX,
				   /* 143 c   */	LETTER|HEX,
				   /* 144 d   */	LETTER|HEX,
				   /* 145 e   */	LETTER|HEX,
				   /* 146 f   */	LETTER|HEX,
				   /* 147 g   */	LETTER,
				   /* 150 h   */	LETTER,
				   /* 151 i   */	LETTER,
				   /* 152 j   */	LETTER,
				   /* 153 k   */	LETTER,
				   /* 154 l   */	LETTER,
				   /* 155 m   */	LETTER,
				   /* 156 n   */	LETTER,
				   /* 157 o   */	LETTER,
				   /* 160 p   */	LETTER,
				   /* 161 q   */	LETTER,
				   /* 162 r   */	LETTER,
				   /* 163 s   */	LETTER,
				   /* 164 t   */	LETTER,
				   /* 165 u   */	LETTER,
				   /* 166 v   */	LETTER,
				   /* 167 w   */	LETTER,
				   /* 170 x   */	LETTER,
				   /* 171 y   */	LETTER,
				   /* 172 z   */	LETTER,
				   /* 173 {   */	OTHER,
				   /* 174 |   */	OTHER,
				   /* 175 }   */	OTHER,
				   /* 176 ~   */	OTHER, };
static struct symbol tval;
static char cbuf[BUFSIZE+1];
static unsigned int wcbuf[BUFSIZE+1];

Coordinate src;		/* current source coordinate */
int t;
char *token;		/* current token */
Symbol tsym;		/* symbol table entry for current token */

static void *cput(int c, void *cl);
static void *wcput(int c, void *cl);
static void *scon(int q, void *put(int c, void *cl), void *cl);
static int backslash(int q);
static Symbol fcon(void);
static Symbol icon(unsigned long, int, int);
static void ppnumber(char *);

int gettok(void) {
	for (;;) {
		register unsigned char *rcp = cp;
		while (map[*rcp]&BLANK)
			rcp++;
		if (limit - rcp < MAXTOKEN) {
			cp = rcp;
			fillbuf();
			rcp = cp;
		}
		src.file = file;
		src.x = (char *)rcp - line;
		src.y = lineno;
		cp = rcp + 1;
		switch (*rcp++) {
		case '/': if (*rcp == '*') {
			  	int c = 0;
			  	for (rcp++; *rcp != '/' || c != '*'; )
			  		if (map[*rcp]&NEWLINE) {
			  			if (rcp < limit)
			  				c = *rcp;
			  			cp = rcp + 1;
			  			nextline();
			  			rcp = cp;
			  			if (rcp == limit)
			  				break;
			  		} else
			  			c = *rcp++;
			  	if (rcp < limit)
			  		rcp++;
			  	else
			  		error("unclosed comment\n");
			  	cp = rcp;
			  	continue;
			  }
			  return '/';
		case '<':
			if (*rcp == '=') return cp++, LEQ;
			if (*rcp == '<') return cp++, LSHIFT;
			return '<';
		case '>':
			if (*rcp == '=') return cp++, GEQ;
			if (*rcp == '>') return cp++, RSHIFT;
			return '>';
		case '-':
			if (*rcp == '>') return cp++, DEREF;
			if (*rcp == '-') return cp++, DECR;
			return '-';
		case '=': return *rcp == '=' ? cp++, EQL    : '=';
		case '!': return *rcp == '=' ? cp++, NEQ    : '!';
		case '|': return *rcp == '|' ? cp++, OROR   : '|';
		case '&': return *rcp == '&' ? cp++, ANDAND : '&';
		case '+': return *rcp == '+' ? cp++, INCR   : '+';
		case ';': case ',': case ':':
		case '*': case '~': case '%': case '^': case '?':
		case '[': case ']': case '{': case '}': case '(': case ')': 
			return rcp[-1];
		case '\n': case '\v': case '\r': case '\f':
			nextline();
			if (cp == limit) {
				tsym = NULL;
				return EOI;
			}
			continue;

		case 'i':
			if (rcp[0] == 'f'
			&& !(map[rcp[1]]&(DIGIT|LETTER))) {
				cp = rcp + 1;
				return IF;
			}
			if (rcp[0] == 'n'
			&&  rcp[1] == 't'
			&& !(map[rcp[2]]&(DIGIT|LETTER))) {
				cp = rcp + 2;
				tsym = inttype->u.sym;
				return INT;
			}
			goto id;
		case 'h': case 'j': case 'k': case 'm': case 'n': case 'o':
		case 'p': case 'q': case 'x': case 'y': case 'z':
		case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
		case 'G': case 'H': case 'I': case 'J': case 'K':
		case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R':
		case 'S': case 'T': case 'U': case 'V': case 'W': case 'X':
		case 'Y': case 'Z':
		id:
			if (limit - rcp < MAXLINE) {
				cp = rcp - 1;
				fillbuf();
				rcp = ++cp;
			}
			assert(cp == rcp);
			token = (char *)rcp - 1;
			while (map[*rcp]&(DIGIT|LETTER))
				rcp++;
			token = stringn(token, (char *)rcp - token);
			tsym = lookup(token, identifiers);
			cp = rcp;
			return ID;
		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9': {
			unsigned long n = 0;
			if (limit - rcp < MAXLINE) {
				cp = rcp - 1;
				fillbuf();
				rcp = ++cp;
			}
			assert(cp == rcp);
			token = (char *)rcp - 1;
			if (*token == '0' && (*rcp == 'x' || *rcp == 'X')) {
				int d, overflow = 0;
				while (*++rcp) {
					if (map[*rcp]&DIGIT)
						d = *rcp - '0';
					else if (*rcp >= 'a' && *rcp <= 'f')
						d = *rcp - 'a' + 10;
					else if (*rcp >= 'A' && *rcp <= 'F')
						d = *rcp - 'A' + 10;
					else
						break;
					if (n&~(~0UL >> 4))
						overflow = 1;
					else
						n = (n<<4) + d;
				}
				if ((char *)rcp - token <= 2)
					error("invalid hexadecimal constant `%S'\n", token, (char *)rcp-token);
				cp = rcp;
				tsym = icon(n, overflow, 16);
			} else if (*token == '0') {
				int err = 0, overflow = 0;
				for ( ; map[*rcp]&DIGIT; rcp++) {
					if (*rcp == '8' || *rcp == '9')
						err = 1;
					if (n&~(~0UL >> 3))
						overflow = 1;
					else
						n = (n<<3) + (*rcp - '0');
				}
				if (*rcp == '.' || *rcp == 'e' || *rcp == 'E') {
					cp = rcp;
					tsym = fcon();
					return FCON;
				}
				cp = rcp;
				tsym = icon(n, overflow, 8);
				if (err)
					error("invalid octal constant `%S'\n", token, (char*)cp-token);
			} else {
				int overflow = 0;
				for (n = *token - '0'; map[*rcp]&DIGIT; ) {
					int d = *rcp++ - '0';
					if (n > (ULONG_MAX - d)/10)
						overflow = 1;
					else
						n = 10*n + d;
				}
				if (*rcp == '.' || *rcp == 'e' || *rcp == 'E') {
					cp = rcp;
					tsym = fcon();
					return FCON;
				}
				cp = rcp;
				tsym = icon(n, overflow, 10);
			}
			return ICON;
		}
		case '.':
			if (rcp[0] == '.' && rcp[1] == '.') {
				cp += 2;
				return ELLIPSIS;
			}
			if ((map[*rcp]&DIGIT) == 0)
				return '.';
			if (limit - rcp < MAXLINE) {
				cp = rcp - 1;
				fillbuf();
				rcp = ++cp;
			}
			assert(cp == rcp);
			cp = rcp - 1;
			token = (char *)cp;
			tsym = fcon();
			return FCON;
		case 'L':
			if (*rcp == '\'') {
				unsigned int *s = scon(*cp, wcput, wcbuf);
				if (s - wcbuf > 2)
					warning("excess characters in wide-character literal ignored\n");
				tval.type = widechar;
				tval.u.c.v.u = wcbuf[0];
				tsym = &tval;
				return ICON;
			} else if (*rcp == '"') {
				unsigned int *s = scon(*cp, wcput, wcbuf);
				tval.type = array(widechar, s - wcbuf, 0);
				tval.u.c.v.p = wcbuf;
				tsym = &tval;
				return SCON;
			} else
				goto id;
		case '\'': {
			char *s = scon(*--cp, cput, cbuf);
			if (s - cbuf > 2)
				warning("excess characters in multibyte character literal ignored\n");
			tval.type = inttype;
			if (chartype->op == INT)
				tval.u.c.v.i = extend(cbuf[0], chartype);
			else
				tval.u.c.v.i = cbuf[0]&0xFF;
			tsym = &tval;
			return ICON;
			}
		case '"': {
			char *s = scon(*--cp, cput, cbuf);
			tval.type = array(chartype, s - cbuf, 0);
			tval.u.c.v.p = cbuf;
			tsym = &tval;
			return SCON;
			}
		case 'a':
			if (rcp[0] == 'u'
			&&  rcp[1] == 't'
			&&  rcp[2] == 'o'
			&& !(map[rcp[3]]&(DIGIT|LETTER))) {
				cp = rcp + 3;
				return AUTO;
			}
			goto id;
		case 'b':
			if (rcp[0] == 'r'
			&&  rcp[1] == 'e'
			&&  rcp[2] == 'a'
			&&  rcp[3] == 'k'
			&& !(map[rcp[4]]&(DIGIT|LETTER))) {
				cp = rcp + 4;
				return BREAK;
			}
			goto id;
		case 'c':
			if (rcp[0] == 'a'
			&&  rcp[1] == 's'
			&&  rcp[2] == 'e'
			&& !(map[rcp[3]]&(DIGIT|LETTER))) {
				cp = rcp + 3;
				return CASE;
			}
			if (rcp[0] == 'h'
			&&  rcp[1] == 'a'
			&&  rcp[2] == 'r'
			&& !(map[rcp[3]]&(DIGIT|LETTER))) {
				cp = rcp + 3;
				tsym = chartype->u.sym;
				return CHAR;
			}
			if (rcp[0] == 'o'
			&&  rcp[1] == 'n'
			&&  rcp[2] == 's'
			&&  rcp[3] == 't'
			&& !(map[rcp[4]]&(DIGIT|LETTER))) {
				cp = rcp + 4;
				return CONST;
			}
			if (rcp[0] == 'o'
			&&  rcp[1] == 'n'
			&&  rcp[2] == 't'
			&&  rcp[3] == 'i'
			&&  rcp[4] == 'n'
			&&  rcp[5] == 'u'
			&&  rcp[6] == 'e'
			&& !(map[rcp[7]]&(DIGIT|LETTER))) {
				cp = rcp + 7;
				return CONTINUE;
			}
			goto id;
		case 'd':
			if (rcp[0] == 'e'
			&&  rcp[1] == 'f'
			&&  rcp[2] == 'a'
			&&  rcp[3] == 'u'
			&&  rcp[4] == 'l'
			&&  rcp[5] == 't'
			&& !(map[rcp[6]]&(DIGIT|LETTER))) {
				cp = rcp + 6;
				return DEFAULT;
			}
			if (rcp[0] == 'o'
			&&  rcp[1] == 'u'
			&&  rcp[2] == 'b'
			&&  rcp[3] == 'l'
			&&  rcp[4] == 'e'
			&& !(map[rcp[5]]&(DIGIT|LETTER))) {
				cp = rcp + 5;
				tsym = doubletype->u.sym;
				return DOUBLE;
			}
			if (rcp[0] == 'o'
			&& !(map[rcp[1]]&(DIGIT|LETTER))) {
				cp = rcp + 1;
				return DO;
			}
			goto id;
		case 'e':
			if (rcp[0] == 'l'
			&&  rcp[1] == 's'
			&&  rcp[2] == 'e'
			&& !(map[rcp[3]]&(DIGIT|LETTER))) {
				cp = rcp + 3;
				return ELSE;