ansi2knr.c

/* Copyright (C) 1989, 1991, 1993 Aladdin Enterprises. All rights reserved. */

/* ansi2knr.c */
/* Convert ANSI function declarations to K&R syntax */

/*
ansi2knr is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
to anyone for the consequences of using it or for whether it serves any
particular purpose or works at all, unless he says so in writing.  Refer
to the GNU General Public License for full details.

Everyone is granted permission to copy, modify and redistribute
ansi2knr, but only under the conditions described in the GNU
General Public License.  A copy of this license is supposed to have been
given to you along with ansi2knr so you can know your rights and
responsibilities.  It should be in a file named COPYING.  Among other
things, the copyright notice and this notice must be preserved on all
copies.
*/

/*
---------- Here is the GNU GPL file COPYING, referred to above ----------
----- These terms do NOT apply to the JPEG software itself; see README ------

		    GHOSTSCRIPT GENERAL PUBLIC LICENSE
		    (Clarified 11 Feb 1988)

 Copyright (C) 1988 Richard M. Stallman
 Everyone is permitted to copy and distribute verbatim copies of this
 license, but changing it is not allowed.  You can also use this wording
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  The license agreements of most software companies keep you at the
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-------------------- End of file COPYING ------------------------------
*/


#include <stdio.h>
#include <ctype.h>

#ifdef BSD
#include <strings.h>
#else
#ifdef VMS
	extern int strlen(), strncmp();
#else
#include <string.h>
#endif
#endif

/* malloc and free should be declared in stdlib.h, */
/* but if you've got a K&R compiler, they probably aren't. */
#ifdef MSDOS
#include <malloc.h>
#else
#ifdef VMS
     extern char *malloc();
     extern void free();
#else
     extern char *malloc();
     extern int free();
#endif
#endif

/* Usage:
	ansi2knr input_file [output_file]
 * If no output_file is supplied, output goes to stdout.
 * There are no error messages.
 *
 * ansi2knr recognizes functions by seeing a non-keyword identifier
 * at the left margin, followed by a left parenthesis,
 * with a right parenthesis as the last character on the line.
 * It will recognize a multi-line header provided that the last character
 * of the last line of the header is a right parenthesis,
 * and no intervening line ends with a left brace or a semicolon.
 * These algorithms ignore whitespace and comments, except that
 * the function name must be the first thing on the line.
 * The following constructs will confuse it:
 *	- Any other construct that starts at the left margin and
 *	    follows the above syntax (such as a macro or function call).
 *	- Macros that tinker with the syntax of the function header.
 */

/* Scanning macros */
#define isidchar(ch) (isalnum(ch) || (ch) == '_')
#define isidfirstchar(ch) (isalpha(ch) || (ch) == '_')

/* Forward references */
char *skipspace();
int writeblanks();
int test1();
int convert1();

/* The main program */
main(argc, argv)
    int argc;
    char *argv[];
{	FILE *in, *out;
#define bufsize 5000			/* arbitrary size */
	char *buf;
	char *line;
	switch ( argc )
	   {
	default:
		printf("Usage: ansi2knr input_file [output_file]\n");
		exit(0);
	case 2:
		out = stdout; break;
	case 3:
		out = fopen(argv[2], "w");
		if ( out == NULL )
		   {	fprintf(stderr, "Cannot open %s\n", argv[2]);
			exit(1);
		   }
	   }
	in = fopen(argv[1], "r");
	if ( in == NULL )
	   {	fprintf(stderr, "Cannot open %s\n", argv[1]);
		exit(1);
	   }
	fprintf(out, "#line 1 \"%s\"\n", argv[1]);
	buf = malloc(bufsize);
	line = buf;
	while ( fgets(line, (unsigned)(buf + bufsize - line), in) != NULL )
	   {	switch ( test1(buf) )
		   {
		case 1:			/* a function */
			convert1(buf, out);
			break;
		case -1:		/* maybe the start of a function */
			line = buf + strlen(buf);
			if ( line != buf + (bufsize - 1) ) /* overflow check */
				continue;
			/* falls through */
		default:		/* not a function */
			fputs(buf, out);
			break;
		   }
		line = buf;
	   }
	if ( line != buf ) fputs(buf, out);
	free(buf);
	fclose(out);
	fclose(in);
	return 0;
}

/* Skip over space and comments, in either direction. */
char *
skipspace(p, dir)
    register char *p;
    register int dir;			/* 1 for forward, -1 for backward */
{	for ( ; ; )
	   {	while ( isspace(*p) ) p += dir;
		if ( !(*p == '/' && p[dir] == '*') ) break;
		p += dir;  p += dir;
		while ( !(*p == '*' && p[dir] == '/') )
		   {	if ( *p == 0 ) return p;	/* multi-line comment?? */
			p += dir;
		   }
		p += dir;  p += dir;
	   }
	return p;
}

/*
 * Write blanks over part of a string.
 */
int
writeblanks(start, end)
    char *start;
    char *end;
{	char *p;
	for ( p = start; p < end; p++ ) *p = ' ';
	return 0;
}

/*
 * Test whether the string in buf is a function definition.
 * The string may contain and/or end with a newline.
 * Return as follows:
 *	0 - definitely not a function definition;
 *	1 - definitely a function definition;
 *	-1 - may be the beginning of a function definition,
 *		append another line and look again.
 */
int
test1(buf)
    char *buf;
{	register char *p = buf;
	char *bend;
	char *endfn;
	int contin;
	if ( !isidfirstchar(*p) )
		return 0;		/* no name at left margin */
	bend = skipspace(buf + strlen(buf) - 1, -1);
	switch ( *bend )
	   {
	case ')': contin = 1; break;
	case '{':
	case ';': return 0;		/* not a function */
	default: contin = -1;
	   }
	while ( isidchar(*p) ) p++;
	endfn = p;
	p = skipspace(p, 1);
	if ( *p++ != '(' )
		return 0;		/* not a function */
	p = skipspace(p, 1);
	if ( *p == ')' )
		return 0;		/* no parameters */
	/* Check that the apparent function name isn't a keyword. */
	/* We only need to check for keywords that could be followed */
	/* by a left parenthesis (which, unfortunately, is most of them). */
	   {	static char *words[] =
		   {	"asm", "auto", "case", "char", "const", "double",
			"extern", "float", "for", "if", "int", "long",
			"register", "return", "short", "signed", "sizeof",
			"static", "switch", "typedef", "unsigned",
			"void", "volatile", "while", 0
		   };
		char **key = words;
		char *kp;
		int len = endfn - buf;
		while ( (kp = *key) != 0 )
		   {	if ( strlen(kp) == len && !strncmp(kp, buf, len) )
				return 0;	/* name is a keyword */
			key++;
		   }
	   }
	return contin;
}

int
convert1(buf, out)
    char *buf;
    FILE *out;
{	char *endfn;
	register char *p;
	char **breaks;
	unsigned num_breaks = 2;	/* for testing */
	char **btop;
	char **bp;
	char **ap;
	/* Pre-ANSI implementations don't agree on whether strchr */
	/* is called strchr or index, so we open-code it here. */
	for ( endfn = buf; *(endfn++) != '('; ) ;
top:	p = endfn;
	breaks = (char **)malloc(sizeof(char *) * num_breaks * 2);
	if ( breaks == 0 )
	   {	/* Couldn't allocate break table, give up */
		fprintf(stderr, "Unable to allocate break table!\n");
		fputs(buf, out);
		return -1;
	   }
	btop = breaks + num_breaks * 2 - 2;
	bp = breaks;
	/* Parse the argument list */
	do
	   {	int level = 0;
		char *end = NULL;
		if ( bp >= btop )
		   {	/* Filled up break table. */
			/* Allocate a bigger one and start over. */
			free((char *)breaks);
			num_breaks <<= 1;
			goto top;
		   }
		*bp++ = p;
		/* Find the end of the argument */
		for ( ; end == NULL; p++ )
		   {	switch(*p)
			   {
			case ',': if ( !level ) end = p; break;
			case '(': level++; break;
			case ')': if ( --level < 0 ) end = p; break;
			case '/': p = skipspace(p, 1) - 1; break;
			default: ;
			   }
		   }
		p--;			/* back up over terminator */
		/* Find the name being declared. */
		/* This is complicated because of procedure and */
		/* array modifiers. */
		for ( ; ; )
		   {	p = skipspace(p - 1, -1);
			switch ( *p )
			   {
			case ']':	/* skip array dimension(s) */
			case ')':	/* skip procedure args OR name */
			   {	int level = 1;
				while ( level )
				 switch ( *--p )
				   {
				case ']': case ')': level++; break;
				case '[': case '(': level--; break;
				case '/': p = skipspace(p, -1) + 1; break;
				default: ;
				   }
			   }
				if ( *p == '(' && *skipspace(p + 1, 1) == '*' )
				   {	/* We found the name being declared */
					while ( !isidfirstchar(*p) )
						p = skipspace(p, 1) + 1;
					goto found;
				   }
				break;
			default: goto found;
			   }
		   }
found:		if ( *p == '.' && p[-1] == '.' && p[-2] == '.' )
		   {	p++;
			if ( bp == breaks + 1 )	/* sole argument */
				writeblanks(breaks[0], p);
			else
				writeblanks(bp[-1] - 1, p);
			bp--;
		   }
		else
		   {	while ( isidchar(*p) ) p--;
			*bp++ = p+1;
		   }
		p = end;
	   }
	while ( *p++ == ',' );
	*bp = p;
	/* Make a special check for 'void' arglist */
	if ( bp == breaks+2 )
	   {	p = skipspace(breaks[0], 1);
		if ( !strncmp(p, "void", 4) )
		   {	p = skipspace(p+4, 1);
			if ( p == breaks[2] - 1 )
			   {	bp = breaks;	/* yup, pretend arglist is empty */
				writeblanks(breaks[0], p + 1);
			   }
		   }
	   }
	/* Put out the function name */
	p = buf;
	while ( p != endfn ) putc(*p, out), p++;
	/* Put out the declaration */
	for ( ap = breaks+1; ap < bp; ap += 2 )
	   {	p = *ap;
		while ( isidchar(*p) ) putc(*p, out), p++;
		if ( ap < bp - 1 ) fputs(", ", out);
	   }
	fputs(")  ", out);
	/* Put out the argument declarations */
	for ( ap = breaks+2; ap <= bp; ap += 2 ) (*ap)[-1] = ';';
	fputs(breaks[0], out);
	free((char *)breaks);
	return 0;
}