/* Copyright (C) 1987, 1990, 1991 Free Software Foundation, Inc.
   
   Modified by Allen Wirfs-Brock, Instantiations Inc 2/90
   */
/* This is the Assembler Pre-Processor
   Copyright (C) 1987 Free Software Foundation, Inc.
   
   This file is part of GAS, the GNU Assembler.
   
   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
   
   GAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* App, the assembler pre-processor.  This pre-processor strips out excess
   spaces, turns single-quoted characters into a decimal constant, and turns
   # <number> <filename> <garbage> into a .line <number>\n.app-file <filename> pair.
   This needs better error-handling.
   */

#include <stdio.h>
#include "as.h"		/* For BAD_CASE() only */

#if !defined(__STDC__) && !defined(const)
#define const /* Nothing */
#endif

static char	lex [256];
static char	symbol_chars[] = 
    "$._ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

/* These will go in BSS if not defined elsewhere, producing empty strings. */
extern const char comment_chars[];
extern const char line_comment_chars[];
extern const char line_separator_chars[];

#define LEX_IS_SYMBOL_COMPONENT		1
#define LEX_IS_WHITESPACE		2
#define LEX_IS_LINE_SEPARATOR		3
#define LEX_IS_COMMENT_START		4
#define LEX_IS_LINE_COMMENT_START	5
#define	LEX_IS_TWOCHAR_COMMENT_1ST	6
#define	LEX_IS_TWOCHAR_COMMENT_2ND	7
#define	LEX_IS_STRINGQUOTE		8
#define	LEX_IS_COLON			9
#define	LEX_IS_NEWLINE			10
#define	LEX_IS_ONECHAR_QUOTE		11
#define IS_SYMBOL_COMPONENT(c)		(lex[c] == LEX_IS_SYMBOL_COMPONENT)
#define IS_WHITESPACE(c)		(lex[c] == LEX_IS_WHITESPACE)
#define IS_LINE_SEPARATOR(c)		(lex[c] == LEX_IS_LINE_SEPARATOR)
#define IS_COMMENT(c)			(lex[c] == LEX_IS_COMMENT_START)
#define IS_LINE_COMMENT(c)		(lex[c] == LEX_IS_LINE_COMMENT_START)
#define	IS_NEWLINE(c)			(lex[c] == LEX_IS_NEWLINE)

/* FIXME-soon: The entire lexer/parser thingy should be
   built statically at compile time rather than dynamically
   each and every time the assembler is run.  xoxorich. */

void do_scrub_begin() {
	const char *p;
	
	lex[' '] = LEX_IS_WHITESPACE;
	lex['\t'] = LEX_IS_WHITESPACE;
	lex['\n'] = LEX_IS_NEWLINE;
	lex[';'] = LEX_IS_LINE_SEPARATOR;
	lex['"'] = LEX_IS_STRINGQUOTE;
	lex['\''] = LEX_IS_ONECHAR_QUOTE;
	lex[':'] = LEX_IS_COLON;
	
	/* Note that these override the previous defaults, e.g. if ';'
	   is a comment char, then it isn't a line separator.  */
	for (p = symbol_chars; *p; ++p) {
		lex[*p] = LEX_IS_SYMBOL_COMPONENT;
	} /* declare symbol characters */
	
	for (p = line_comment_chars; *p; p++) {
		lex[*p] = LEX_IS_LINE_COMMENT_START;
	} /* declare line comment chars */
	
	for (p = comment_chars; *p; p++) {
		lex[*p] = LEX_IS_COMMENT_START;
	} /* declare comment chars */
	
	for (p = line_separator_chars; *p; p++) {
		lex[*p] = LEX_IS_LINE_SEPARATOR;
	} /* declare line separators */
	
	/* Only allow slash-star comments if slash is not in use */
	if (lex['/'] == 0) {
		lex['/'] = LEX_IS_TWOCHAR_COMMENT_1ST;
	}
	/* FIXME-soon.  This is a bad hack but otherwise, we
	   can't do c-style comments when '/' is a line
	   comment char. xoxorich. */
	if (lex['*'] == 0) {
		lex['*'] = LEX_IS_TWOCHAR_COMMENT_2ND;
	}
} /* do_scrub_begin() */

FILE *scrub_file;

int scrub_from_file() {
	return getc(scrub_file);
}

void scrub_to_file(ch)
int ch;
{
	ungetc(ch,scrub_file);
} /* scrub_to_file() */

char *scrub_string;
char *scrub_last_string;

int scrub_from_string() {
	return scrub_string == scrub_last_string ? EOF : *scrub_string++;
} /* scrub_from_string() */

void scrub_to_string(ch)
int ch;
{
	*--scrub_string=ch;
} /* scrub_to_string() */

/* Saved state of the scrubber */
static int state;
static int old_state;
static char *out_string;
static char out_buf[20];
static int add_newlines = 0;

/* Data structure for saving the state of app across #include's.  Note that
   app is called asynchronously to the parsing of the .include's, so our
   state at the time .include is interpreted is completely unrelated.
   That's why we have to save it all.  */

struct app_save {
	int state;
	int old_state;
	char *out_string;
	char out_buf[sizeof (out_buf)];
	int add_newlines;
	char *scrub_string;
	char *scrub_last_string;
	FILE *scrub_file;
};

char *app_push() {
	register struct app_save *saved;
	
	saved = (struct app_save *) xmalloc(sizeof (*saved));
	saved->state		= state;
	saved->old_state	= old_state;
	saved->out_string	= out_string;
	bcopy(saved->out_buf, out_buf, sizeof(out_buf));
	saved->add_newlines	= add_newlines;
	saved->scrub_string	= scrub_string;
	saved->scrub_last_string = scrub_last_string;
	saved->scrub_file	= scrub_file;
	
	/* do_scrub_begin() is not useful, just wastes time. */
	return (char *)saved;
}

void app_pop(arg)
char *arg;
{
	register struct app_save *saved = (struct app_save *)arg;
	
	/* There is no do_scrub_end (). */
	state		= saved->state;
	old_state	= saved->old_state;
	out_string	= saved->out_string;
	bcopy (out_buf,  saved->out_buf, sizeof (out_buf));
	add_newlines	= saved->add_newlines;
	scrub_string	= saved->scrub_string;
	scrub_last_string = saved->scrub_last_string;
	scrub_file	= saved->scrub_file;
	
	free (arg);
} /* app_pop() */

int do_scrub_next_char(get,unget)
int (*get)();
void (*unget)();
{
	/*State 0: beginning of normal line
	  1: After first whitespace on line (flush more white)
	  2: After first non-white (opcode) on line (keep 1white)
	  3: after second white on line (into operands) (flush white)
	  4: after putting out a .line, put out digits
	  5: parsing a string, then go to old-state
	  6: putting out \ escape in a "d string.
	  7: After putting out a .app-file, put out string.
	  8: After putting out a .app-file string, flush until newline.
	  -1: output string in out_string and go to the state in old_state
	  -2: flush text until a '*' '/' is seen, then go to state old_state
	  */
	
	register int ch, ch2 = 0;
	
	switch (state) {
	case -1: 
		ch= *out_string++;
		if(*out_string==0) {
			state=old_state;
			old_state=3;
		}
		return ch;
		
	case -2:
		for(;;) {
			do {
				ch=(*get)();
			} while(ch!=EOF && ch!='\n' && ch!='*');
			if(ch=='\n' || ch==EOF)
			    return ch;
			
			/* At this point, ch must be a '*' */
			while ( (ch=(*get)()) == '*' ){
				;
			}
			if(ch==EOF || ch=='/')
			    break;
			(*unget)(ch);
		}
		state=old_state;
		return ' ';
		
	case 4:
		ch=(*get)();
		if(ch==EOF || (ch>='0' && ch<='9'))
		    return ch;
		else {
			while(ch!=EOF && IS_WHITESPACE(ch))
			    ch=(*get)();
			if(ch=='"') {
				(*unget)(ch);
				out_string="\n.app-file ";
				old_state=7;
				state= -1;
				return *out_string++;
			} else {
				while(ch!=EOF && ch!='\n')
				    ch=(*get)();
				return ch;
			}
		}
		
	case 5:
		ch=(*get)();
		if(ch=='"') {
			state=old_state;
			return '"';
		} else if(ch=='\\') {
			state=6;
			return ch;
		} else if(ch==EOF) {
			as_warn("End of file in string: inserted '\"'");
 			state=old_state;
			(*unget)('\n');
			return '"';
		} else {
			return ch;
		}
		
	case 6:
		state=5;
		ch=(*get)();
		switch(ch) {
			/* This is neet.  Turn "string
			   more string" into "string\n  more string"
			   */
		case '\n':
			(*unget)('n');
			add_newlines++;
			return '\\';
			
		case '"':
		case '\\':
		case 'b':
		case 'f':
		case 'n':
		case 'r':
		case 't':
#ifdef BACKSLASH_V
		case 'v':
#endif /* BACKSLASH_V */
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
			break;
			
#ifdef ONLY_STANDARD_ESCAPES
		default:
			as_warn("Unknown escape '\\%c' in string: Ignored",ch);
			break;
#else /* ONLY_STANDARD_ESCAPES */
		default:
			/* Accept \x as x for any x */
			break;
#endif /* ONLY_STANDARD_ESCAPES */
			
		case EOF:
			as_warn("End of file in string: '\"' inserted");
			return '"';
		}
		return ch;
		
	case 7:
		ch=(*get)();
		state=5;
		old_state=8;
		return ch;
		
	case 8:
		do ch= (*get)();
		while(ch!='\n');
		state=0;
		return ch;
	}
	
	/* OK, we are somewhere in states 0 through 4 */
	
	/* flushchar: */
	ch=(*get)();
 recycle:
	if (ch == EOF) {
		if (state != 0)
		    as_warn("End of file not at end of a line: Newline inserted.");
		return ch;
	}
	
	switch (lex[ch]) {
	case LEX_IS_WHITESPACE:
		do ch=(*get)();
		while(ch!=EOF && IS_WHITESPACE(ch));
		if(ch==EOF)
		    return ch;
		if(IS_COMMENT(ch) || (state==0 && IS_LINE_COMMENT(ch)) || ch=='/' || IS_LINE_SEPARATOR(ch)) {
			goto recycle;
		}
		switch (state) {
		case 0:	state++; goto recycle;	/* Punted leading sp */
		case 1:          BAD_CASE(state); /* We can't get here */
		case 2: state++; (*unget)(ch); return ' ';  /* Sp after opco */
		case 3:		 goto recycle;	/* Sp in operands */
		default:	BAD_CASE(state);
		}
		break;
		
	case LEX_IS_TWOCHAR_COMMENT_1ST:
		ch2=(*get)();
		if (ch2 != EOF && lex[ch2] == LEX_IS_TWOCHAR_COMMENT_2ND) {
			for(;;) {
				do {
					ch2=(*get)();
					if(ch2 != EOF && IS_NEWLINE(ch2))
					    add_newlines++;
				} while(ch2!=EOF &&
					(lex[ch2] != LEX_IS_TWOCHAR_COMMENT_2ND));
				
				while (ch2!=EOF &&
				       (lex[ch2] == LEX_IS_TWOCHAR_COMMENT_2ND)){
					ch2=(*get)();
				}
				
				if(ch2==EOF 
				   || lex[ch2] == LEX_IS_TWOCHAR_COMMENT_1ST)
				    break;
				(*unget)(ch);
			}
			if(ch2==EOF)
			    as_warn("End of file in multiline comment");
			
			ch = ' ';
			goto recycle;
		} else {
			if(ch2!=EOF)
			    (*unget)(ch2);
			return ch;
		}
		break;
		
	case LEX_IS_STRINGQUOTE:
		old_state=state;
		state=5;
		return ch;
		
#ifndef IEEE_STYLE
	case LEX_IS_ONECHAR_QUOTE:
		ch=(*get)();
		if(ch==EOF) {
			as_warn("End-of-file after a one-character quote; \000 inserted");
			ch=0;
		}
		sprintf(out_buf,"%d", (int)(unsigned char)ch);
		
		/* None of these 'x constants for us.  We want 'x'.
		 */
		if ( (ch=(*get)()) != '\'' ) {
#ifdef REQUIRE_CHAR_CLOSE_QUOTE
			as_warn("Missing close quote: (assumed)");
#else
			(*unget)(ch);
#endif
		}
		
		old_state=state;
		state= -1;
		out_string=out_buf;
		return *out_string++;
#endif
	case LEX_IS_COLON:
		if(state!=3)
		    state=0;
		return ch;
		
	case LEX_IS_NEWLINE:
		/* Roll out a bunch of newlines from inside comments, etc.  */
		if(add_newlines) {
			--add_newlines;
			(*unget)(ch);
		}
		/* fall thru into... */
		
	case LEX_IS_LINE_SEPARATOR:
		state=0;
		return ch;
		
	case LEX_IS_LINE_COMMENT_START:
		if (state != 0)		/* Not at start of line, act normal */
		    goto de_fault;
		
		/* FIXME-someday: The two character comment stuff was badly
		   thought out.  On i386, we want '/' as line comment start
		   AND we want C style comments.  hence this hack.  The
		   whole lexical process should be reworked.  xoxorich.  */
		
		if (ch == '/' && (ch2 = (*get)()) == '*') {
			state = -2;
			return(do_scrub_next_char(get, unget));
		} else {
			(*unget)(ch2);
		} /* bad hack */
		
		do ch=(*get)();
		while(ch!=EOF && IS_WHITESPACE(ch));
		if(ch==EOF) {
			as_warn("EOF in comment:  Newline inserted");
			return '\n';
		}
		if(ch<'0' || ch>'9') {
			/* Non-numerics:  Eat whole comment line */
			while(ch!=EOF && !IS_NEWLINE(ch))
			    ch=(*get)();
			if(ch==EOF)
			    as_warn("EOF in Comment: Newline inserted");
			state=0;
			return '\n';
		}
		/* Numerics begin comment.  Perhaps CPP `# 123 "filename"' */
		(*unget)(ch);
		old_state=4;
		state= -1;
		out_string=".line ";
		return *out_string++;
		
	case LEX_IS_COMMENT_START:
		do ch=(*get)();
		while(ch!=EOF && !IS_NEWLINE(ch));
		if(ch==EOF)
		    as_warn("EOF in comment:  Newline inserted");
		state=0;
		return '\n';
		
	default:
	de_fault:
		/* Some relatively `normal' character.  */
		if(state==0) {
			state=2;	/* Now seeing opcode */
			return ch;
		} else if(state==1) {
			state=2;	/* Ditto */
			return ch;
		} else {
			return ch;	/* Opcode or operands already */
		}
	}
	return -1;
}

#ifdef TEST

char comment_chars[] = "|";
char line_comment_chars[] = "#";

main()
{
	int	ch;
	
	app_begin();
	while((ch=do_scrub_next_char(stdin))!=EOF)
	    putc(ch,stdout);
}

as_warn(str)
char *str;
{
	fputs(str,stderr);
	putc('\n',stderr);
}
#endif

/*
 * Local Variables:
 * comment-column: 0
 * fill-column: 131
 * End:
 */

/* end of app.c */