src/sys/ddb/db_lex.c

/*	$OpenBSD: db_lex.c,v 1.15 2020/10/15 03:14:00 deraadt Exp $	*/
/*	$NetBSD: db_lex.c,v 1.8 1996/02/05 01:57:05 christos Exp $	*/

/*
 * Mach Operating System
 * Copyright (c) 1993,1992,1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 *
 *	Author: David B. Golub, Carnegie Mellon University
 *	Date:	7/90
 */

/*
 * Lexical analyzer.
 */
#include <sys/param.h>
#include <sys/systm.h>

#include <machine/db_machdep.h>

#include <ddb/db_lex.h>
#include <ddb/db_output.h>
#include <ddb/db_command.h>
#include <ddb/db_extern.h>
#include <ddb/db_var.h>

char	db_line[120];
char *	db_lp, *db_endlp;

db_expr_t db_tok_number;
char	db_tok_string[TOK_STRING_SIZE];

void db_flush_line(void);
int db_read_char(void);
void db_unread_char(int);

int
db_read_line(void)
{
	int	i;

	i = db_readline(db_line, sizeof(db_line));
	if (i == 0)
		return (0);	/* EOI */
	db_lp = db_line;
	db_endlp = db_lp + i;
	return (i);
}

void
db_flush_line(void)
{
	db_lp = db_line;
	db_endlp = db_line;
}

int	db_look_char = 0;

int
db_read_char(void)
{
	int	c;

	if (db_look_char != 0) {
		c = db_look_char;
		db_look_char = 0;
	} else if (db_lp >= db_endlp)
		c = -1;
	else
		c = *db_lp++;
	return (c);
}

void
db_unread_char(int c)
{
	db_look_char = c;
}

int	db_look_token = 0;

void
db_unread_token(int t)
{
	db_look_token = t;
}

int
db_read_token(void)
{
	int	t;

	if (db_look_token) {
		t = db_look_token;
		db_look_token = 0;
	} else
		t = db_lex();
	return (t);
}

void
db_flush_lex(void)
{
	db_flush_line();
	db_look_char = 0;
	db_look_token = 0;
}

int
db_lex(void)
{
	int	c;

	c = db_read_char();
	while (c <= ' ' || c > '~') {
		if (c == '\n' || c == -1)
			return (tEOL);
		c = db_read_char();
	}

	if (c >= '0' && c <= '9') {
		/* number */
		int	r, digit = 0;

		if (c > '0')
			r = db_radix;
		else {
			c = db_read_char();
			if (c == 'O' || c == 'o')
				r = 8;
			else if (c == 'T' || c == 't')
				r = 10;
			else if (c == 'X' || c == 'x')
				r = 16;
			else {
				r = db_radix;
				db_unread_char(c);
			}
			c = db_read_char();
		}
		db_tok_number = 0;
		for (;;) {
			if (c >= '0' && c <= ((r == 8) ? '7' : '9'))
				digit = c - '0';
			else if (r == 16 && ((c >= 'A' && c <= 'F') ||
			    (c >= 'a' && c <= 'f'))) {
				if (c >= 'a')
					digit = c - 'a' + 10;
				else if (c >= 'A')
					digit = c - 'A' + 10;
			} else
				break;
			db_tok_number = db_tok_number * r + digit;
			c = db_read_char();
		}
		if ((c >= '0' && c <= '9') ||
		    (c >= 'A' && c <= 'Z') ||
		    (c >= 'a' && c <= 'z') ||
		    (c == '_')) {
			db_error("Bad character in number\n");
			/*NOTREACHED*/
		}
		db_unread_char(c);
		return (tNUMBER);
	}
	if ((c >= 'A' && c <= 'Z') ||
	    (c >= 'a' && c <= 'z') ||
	    c == '_' || c == '\\') {
		/* string */
		char *cp;

		cp = db_tok_string;
		if (c == '\\') {
			c = db_read_char();
			if (c == '\n' || c == -1) {
				db_error("Bad escape\n");
				/*NOTREACHED*/
			}
		}
		*cp++ = c;
		while (1) {
			c = db_read_char();
			if ((c >= 'A' && c <= 'Z') ||
			    (c >= 'a' && c <= 'z') ||
			    (c >= '0' && c <= '9') ||
			    c == '_' || c == '\\' || c == ':') {
				if (c == '\\') {
					c = db_read_char();
					if (c == '\n' || c == -1) {
						db_error("Bad escape\n");
						/*NOTREACHED*/
					}
				}
				*cp++ = c;
				if (cp == db_tok_string+sizeof(db_tok_string)) {
					db_error("String too long\n");
					/*NOTREACHED*/
				}
				continue;
			} else {
				*cp = '\0';
				break;
			}
		}
		db_unread_char(c);
		return (tIDENT);
	}

	switch (c) {
	case '+':
		return (tPLUS);
	case '-':
		return (tMINUS);
	case '.':
		c = db_read_char();
		if (c == '.')
			return (tDOTDOT);
		db_unread_char(c);
		return (tDOT);
	case '*':
		return (tSTAR);
	case '/':
		return (tSLASH);
	case '=':
		return (tEQ);
	case '%':
		return (tPCT);
	case '#':
		return (tHASH);
	case '(':
		return (tLPAREN);
	case ')':
		return (tRPAREN);
	case ',':
		return (tCOMMA);
	case '"':
		return (tDITTO);
	case '$':
		return (tDOLLAR);
	case '!':
		return (tEXCL);
	case '<':
		c = db_read_char();
		if (c == '<')
			return (tSHIFT_L);
		db_unread_char(c);
		break;
	case '>':
		c = db_read_char();
		if (c == '>')
			return (tSHIFT_R);
		db_unread_char(c);
		break;
	case -1:
		return (tEOF);
	}
	db_printf("Bad character\n");
	db_flush_lex();
	return (tEOF);
}