scanner.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/************************************************************************
 *									*
 *			Copyright (c) 1986, 1989 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *									*
 *			Modification History				*
 *									*
 *	005 - Made # and \ work as expected in shellmode.		*
 *	      (Jon Reeves, January 21, 1989)				*
 *									*
 *      004 - Added a <cr> for the -x option for use with xdb           *
 *            (David Metsky, March 8, 1988)				*
 *									*
 *	003 - Merged in 4.3 changes.					*
 *	      (vjh, April 29, 1986)					*
 *									*
 *	002 - Update copyright.						*
 *	      (vjh, August 23, 1985)					*
 *									*
 *	001 - Added saved-command feature:  <cr> alone on a command 	*
 *	      line reexecutes previously entered command.		*
 *	      (Victoria Holt, April 9, 1985)				*
 *									*
 ************************************************************************/

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

/* derived from: "@(#)scanner.c	5.1 (Berkeley) 5/31/85" */
#ifndef lint
static char sccsid[] = "@(#)scanner.c	4.2	ULTRIX	11/9/90";
#endif not lint

static char rcsid[] = "$Header: scanner.c,v 1.5 84/12/26 10:42:05 linton Exp $";

/*
 * Debugger scanner.
 */

#include "defs.h"
#include "scanner.h"
#include "main.h"
#include "keywords.h"
#include "tree.h"
#include "symbols.h"
#include "names.h"
#include "y.tab.h"

#ifndef public
typedef int Token;

#define MAXLINESIZE 10240

#endif

public String initfile;
public boolean xdb;		/* xdb specific features */

typedef enum { WHITE, ALPHA, NUM, OTHER } Charclass;

private Charclass class[256 + 1];
private Charclass *lexclass = class + 1;

#define isdigit(c) (lexclass[c] == NUM)
#define isalnum(c) (lexclass[c] == ALPHA or lexclass[c] == NUM)
#define ishexdigit(c) ( \
    isdigit(c) or (c >= 'a' and c <= 'f') or (c >= 'A' and c <= 'F') \
)

public boolean chkalias;
public char scanner_linebuf[MAXLINESIZE];

private File in;
private File recorded_input;
private char *record_name = nil;
private char *curchar, *prevchar;
private char prevbuf[MAXLINESIZE];

#define MAXINCLDEPTH 10

private struct {
    File savefile;
    Filename savefn;
    int savelineno;
} inclinfo[MAXINCLDEPTH];

private unsigned int curinclindex;

private Token getident();
private Token getnum();
private Token getstring();
private Boolean eofinput();
private char charcon();

private enterlexclass(class, s)
Charclass class;
String s;
{
    register char *p;

    for (p = s; *p != '\0'; p++) {
	lexclass[*p] = class;
    }
}

public set_record(string)
char *string;
{
	if(record_name != nil) {
		fclose(recorded_input);
		record_name = nil;
	}
	if(strlen(string)) {
		if((recorded_input = fopen(string, "w")) != nil) {
			record_name = strdup(string);
		} else {
			error("unable to open %s for recording", string);
		}
	}
}

public scanner_init()
{
    register Integer i;

    for (i = 0; i < 257; i++) {
	class[i] = OTHER;
    }
    enterlexclass(WHITE, " \t");
    enterlexclass(ALPHA, "abcdefghijklmnopqrstuvwxyz");
    enterlexclass(ALPHA, "ABCDEFGHIJKLMNOPQRSTUVWXYZ_$");
    enterlexclass(NUM, "0123456789");
    in = stdin;
    errfilename = nil;
    errlineno = 0;
    curchar = scanner_linebuf;
    scanner_linebuf[0] = '\0';
    prevbuf[0] = '\n';
    chkalias = true;
}

/*
 * Read a single token.
 *
 * The input is line buffered.  Tokens cannot cross line boundaries.
 *
 * There are two "modes" of operation:  one as in a compiler,
 * and one for reading shell-like syntax.  In the first mode
 * there is the additional choice of doing alias processing.
 */

private Boolean shellmode;

public Token yylex()
{
    register int c;
    register char *p;
    register Token t;
    String line;
    integer n;

    p = curchar;
    if (*p == '\0') {
	do {
	    if (isterm(in)) {
		printf("(%s) ", cmdname);
		if (xdb) {     /* 004 - DNM */
		    printf("\n");
		}
	    }
	    fflush(stdout);
	    line = fgets(scanner_linebuf, MAXLINESIZE, in);
	} while (line == nil and not eofinput());
	if (line == nil) {
	    c = EOF;
	} else {
	    p = scanner_linebuf;
	    while (lexclass[*p] == WHITE) {
		p++;
	    }
	    if (*p == '\n') {
	        strcpy(scanner_linebuf, prevbuf);
		p = scanner_linebuf;
	    } else {
	        strcpy(prevbuf, p);
	    }
	    shellmode = false;
	}
	Iline_alloc(p);
	if(record_name != nil) {
		fputs(p, recorded_input);
    }
	chkalias = true;
    } else {
	while (lexclass[*p] == WHITE) {
	    p++;
	}
    }
    curchar = p;
    prevchar = curchar;
    c = *p;
    if (lexclass[c] == ALPHA) {
	t = getident(chkalias);
    } else if (lexclass[c] == NUM) {
	if (shellmode) {
	    t = getident(chkalias);
	} else {
	    t = getnum();
	}
    } else {
	++curchar;
	switch (c) {
	    case '\n':
		t = '\n';
		if (errlineno != 0) {
		    errlineno++;
		}
		break;

	    case '"':
	    case '\'':
		t = getstring(c);
		break;

	    case '.':
		if (shellmode) {
		    --curchar;
		    t = getident(chkalias);
		} else if (isdigit(*curchar)) {
		    --curchar;
		    t = getnum();
		} else {
		    t = '.';
		}
		break;

	    case '-':
		if (shellmode) {
		    --curchar;
		    t = getident(chkalias);
		} else if (*curchar == '>') {
		    ++curchar;
		    t = ARROW;
		} else {
		    t = '-';
		}
		break;

	    case '#':
		if (shellmode) {
		    --curchar;
		    t = getident(chkalias);
		} else if (not isterm(in)) {
		    *p = '\0';
		    curchar = p;
		    t = '\n';
		    ++errlineno;
		} else {
		    t = '#';
		}
		break;

	    case '\\':
		if (*(p+1) == '\n') {
		    n = MAXLINESIZE - (p - &scanner_linebuf[0]);
		    if (n > 1) {
			if (fgets(p, n, in) == nil) {
			    t = 0;
			} else {
			    curchar = p;
			    t = yylex();
			}
		    } else {
			if (shellmode) {
			    --curchar;
			    t = getident(chkalias);
			} else {
			    t = '\\';
			}
		    }
		} else {
		    if (shellmode) {
			--curchar;
			t = getident(chkalias);
		    } else {
			t = '\\';
		    }
		}
		break;

	    case EOF:
		t = 0;
		break;

	    default:
		if (shellmode and index("!&*<>()[]", c) == nil) {
		    --curchar;
		    t = getident(chkalias);
		} else {
		    t = c;
		}
		break;
	}
    }
    chkalias = false;
#   ifdef LEXDEBUG
	if (lexdebug) {
	    fprintf(stderr, "yylex returns ");
	    print_token(stderr, t);
	    fprintf(stderr, "\n");
	}
#   endif
	if(t == DELETE) {
		char *tmp;
		
		if(strncmp((tmp = (char *)strpbrk(line, "a")), "all", 3) == 0) {
			tmp[0] = '*';
			tmp[1] = ' ';
			tmp[2] = ' ';
		}
	}
    return t;
}

/*
 * Put the given string before the current character
 * in the current line, thus inserting it into the input stream.
 */

public insertinput (s)
String s;
{
    register char *p, *q;
    int need, avail, shift;

    q = s;
    need = strlen(q);
    avail = curchar - &scanner_linebuf[0];
    if (need <= avail) {
	curchar = &scanner_linebuf[avail - need];
	p = curchar;
	while (*q != '\0') {
	    *p++ = *q++;
	}
    } else {
	p = curchar;
	while (*p != '\0') {
	    ++p;
	}
	shift = need - avail;
	if (p + shift >= &scanner_linebuf[MAXLINESIZE]) {
	    error("alias expansion too large");
	}
	for (;;) {
	    *(p + shift) = *p;
	    if (p == curchar) {
		break;
	    }
	    --p;
	}
	p = &scanner_linebuf[0];
	while (*q != '\0') {
	    *p++ = *q++;
	}
	curchar = &scanner_linebuf[0];
    }
}

/*
 * Get the actuals for a macro call.
 */

private String movetochar (str, c)
String str;
char c;
{
    register char *p;

    while (*p != c) {
	if (*p == '\0') {
	    error("missing ')' in macro call");
	} else if (*p == ')') {
	    error("not enough parameters in macro call");
	} else if (*p == ',') {
	    error("too many parameters in macro call");
	}
	++p;
    }
    return p;
}

private String *getactuals (n)
integer n;
{
    String *a;
    register char *p;
    int i;

    a = newarr(String, n);
    p = curchar;
    while (*p != '(') {
	if (lexclass[*p] != WHITE) {
	    error("missing actuals for macro");
	}
	++p;
    }
    ++p;
    for (i = 0; i < n - 1; i++) {
	a[i] = p;
	p = movetochar(p, ',');
	*p = '\0';
	++p;
    }
    a[n-1] = p;
    p = movetochar(p, ')');
    *p = '\0';
    curchar = p + 1;
    return a;
}

/*
 * Do command macro expansion, assuming curchar points to the beginning
 * of the actuals, and we are not in shell mode.
 */

private expand (pl, str)
List pl;
String str;
{
    char buf[4096], namebuf[100];
    register char *p, *q, *r;
    String *actual;
    Name n;
    integer i;
    boolean match;

    if (pl == nil) {
	insertinput(str);
    } else {
	actual = getactuals(list_size(pl));
	p = buf;
	q = str;
	while (*q != '\0') {
	    if (p >= &buf[4096]) {
		error("alias expansion too large");
	    }
	    if (lexclass[*q] == ALPHA) {