ansi2knr.c

linux下的jpeg解码库

	  }
	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 output file %s\n", argv[2]);
			exit(1);
		   }
	   }
	in = fopen(argv[1], "r");
	if ( in == NULL )
	   {	fprintf(stderr, "Cannot open input file %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 )
	   {
test:		line += strlen(line);
		switch ( test1(buf) )
		   {
		case 2:			/* a function header */
			convert1(buf, out, 1, convert_varargs);
			break;
		case 1:			/* a function */
			/* Check for a { at the start of the next line. */
			more = ++line;
f:			if ( line >= buf + (bufsize - 1) ) /* overflow check */
			  goto wl;
			if ( fgets(line, (unsigned)(buf + bufsize - line), in) == NULL )
			  goto wl;
			switch ( *skipspace(more, 1) )
			  {
			  case '{':
			    /* Definitely a function header. */
			    convert1(buf, out, 0, convert_varargs);
			    fputs(more, out);
			    break;
			  case 0:
			    /* The next line was blank or a comment: */
			    /* keep scanning for a non-comment. */
			    line += strlen(line);
			    goto f;
			  default:
			    /* buf isn't a function header, but */
			    /* more might be. */
			    fputs(buf, out);
			    strcpy(buf, more);
			    line = buf;
			    goto test;
			  }
			break;
		case -1:		/* maybe the start of a function */
			if ( line != buf + (bufsize - 1) ) /* overflow check */
			  continue;
			/* falls through */
		default:		/* not a function */
wl:			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 ( is_space(*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.
 * Don't overwrite end-of-line characters.
 */
int
writeblanks(start, end)
    char *start;
    char *end;
{	char *p;
	for ( p = start; p < end; p++ )
	  if ( *p != '\r' && *p != '\n' )
	    *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;
 *	2 - definitely a function prototype (NOT USED);
 *	-1 - may be the beginning of a function definition,
 *		append another line and look again.
 * The reason we don't attempt to convert function prototypes is that
 * Ghostscript's declaration-generating macros look too much like
 * prototypes, and confuse the algorithms.
 */
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 = 0 /*2*/; break;
	   case ')': contin = 1; break;
	   case '{': return 0;		/* not a function */
	   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;
}

/* Convert a recognized function definition or header to K&R syntax. */
int
convert1(buf, out, header, convert_varargs)
    char *buf;
    FILE *out;
    int header;			/* Boolean */
    int convert_varargs;	/* Boolean */
{	char *endfn;
	register char *p;
	char **breaks;
	unsigned num_breaks = 2;	/* for testing */
	char **btop;
	char **bp;
	char **ap;
	char *vararg = 0;

	/* 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 *lp = NULL;
		char *rp;
		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 '(':
				if ( !level ) lp = p;
				level++;
				break;
			   case ')':
				if ( --level < 0 ) end = p;
				else rp = p;
				break;
			   case '/':
				p = skipspace(p, 1) - 1;
				break;
			   default:
				;
			   }
		   }
		/* Erase any embedded prototype parameters. */
		if ( lp )
		  writeblanks(lp + 1, rp);
		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] == '.' )
		  {	if ( convert_varargs )
			  {	*bp++ = "va_alist";
				vararg = p-2;
			  }
			else
			  {	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 and left parenthesis. */
	p = buf;
	while ( p != endfn ) putc(*p, out), p++;
	/* Put out the declaration. */
	if ( header )
	  {	fputs(");", out);
		for ( p = breaks[0]; *p; p++ )
		  if ( *p == '\r' || *p == '\n' )
		    putc(*p, out);
	  }
	else
	  {	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] = ';';
		if ( vararg != 0 )
		  {	*vararg = 0;
			fputs(breaks[0], out);		/* any prior args */
			fputs("va_dcl", out);		/* the final arg */
			fputs(bp[0], out);
		  }
		else
		  fputs(breaks[0], out);
	  }
	free((char *)breaks);
	return 0;
}