/* aslex.c */

/*
 * (C) Copyright 1989-1995
 * All Rights Reserved
 *
 * Alan R. Baldwin
 * 721 Berkeley St.
 * Kent, Ohio  44240
 */

/*
 * Extensions: P. Felber, M. Hope
 */

#include <stdio.h>
#include <setjmp.h>
#include <string.h>
#include <alloc.h>
#include "asm.h"

/*)Module	aslex.c
 *
 *	The module aslex.c includes the general lexical
 *	analysis routines for the assembler.
 *
 *	aslex.c contains the following functions:
 *		char	endline()
 *		char	get()
 *		VOID	getid(id,c)
 *		int	getline()
 *		int	getmap()
 *		char	getnb()
 *		VOID	getst()
 *		int	more()
 *		VOID	unget(c)
 *
 *	aslex.c contains no local/static variables
 */

/*)Function	VOID	getid(id,c)
 *
 *		char *	id		a pointer to a string of
 *					maximum length NCPS
 *		int	c		mode flag
 *					>=0	this is first character to
 *						copy to the string buffer
 *					<0	skip white space, first
 *						character must be a LETTER
 *
 *	The function getid() scans the current assembler-source text line
 *	from the current position copying the next LETTER | DIGIT string
 *	into the external string buffer (id).  The string ends when a non
 *	LETTER or DIGIT character is found. The maximum number of
 *	characters copied is NCPS.  If the input string is larger than
 *	NCPS characters then the string is truncated, if the input string
 *	is shorter than NCPS characters then the string is NULL filled.
 *	If the mode argument (c) is >=0 then (c) is the first character
 *	copied to the string buffer, if (c) is <0 then intervening white
 *	space (SPACES and TABS) are skipped and the first character found
 *	must be a LETTER else a 'q' error terminates the parse of this
 *	assembler-source text line.
 *
 *	local variables:
 *		char *	p		pointer to external string buffer
 *		int	c		current character value
 *
 *	global variables:
 *		char	ctype[]		a character array which defines the
 *					type of character being processed.
 *					This index is the character
 *					being processed.
 *
 *	called functions:
 *		char	get()		aslex.c
 *		char	getnb()		aslex.c
 *		VOID	unget()		aslex.c
 *
 *	side effects:
 *		use of getnb(), get(), and unget() updates the
 *		global pointer ip, the position in the current
 *		assembler-source text line.
 */

VOID
getid(id, c)
register c;
char *id;
{
	register char *p;

	if (c < 0) {
		c = getnb();
		if ((ctype[c] & LETTER) == 0)
			qerr();
	}
	p = id;
	do {
		if (p < &id[NCPS])
			*p++ = c;
	} while (ctype[c=get()] & (LETTER|DIGIT));
	unget(c);
	while (p < &id[NCPS])
		*p++ = 0;
}

/*)Function	VOID	getst(id,c)
 *
 *		char *	id		a pointer to a string of
 *					maximum length NCPS
 *		int	c		mode flag
 *					>=0	this is first character to
 *						copy to the string buffer
 *					<0	skip white space, first
 *						character must be a LETTER
 *
 *	The function getnbid() scans the current assembler-source text line
 *	from the current position copying the next character string into
 *	the external string buffer (id).  The string ends when a SPACE or
 *	ILL character is found. The maximum number of
 *	characters copied is NCPS.  If the input string is larger than
 *	NCPS characters then the string is truncated, if the input string
 *	is shorter than NCPS characters then the string is NULL filled.
 *	If the mode argument (c) is >=0 then (c) is the first character
 *	copied to the string buffer, if (c) is <0 then intervening white
 *	space (SPACES and TABS) are skipped and the first character found
 *	must be a LETTER else a 'q' error terminates the parse of this
 *	assembler-source text line.
 *
 *	local variables:
 *		char *	p		pointer to external string buffer
 *		int	c		current character value
 *
 *	global variables:
 *		char	ctype[]		a character array which defines the
 *					type of character being processed.
 *					This index is the character
 *					being processed.
 *
 *	called functions:
 *		char	get()		aslex.c
 *		char	getnb()		aslex.c
 *		VOID	unget()		aslex.c
 *
 *	side effects:
 *		use of getnb(), get(), and unget() updates the
 *		global pointer ip, the position in the current
 *		assembler-source text line.
 */

VOID
getst(id, c)
register c;
char *id;
{
	register char *p;

	if (c < 0) {
		c = getnb();
		if ((ctype[c] & LETTER) == 0)
			qerr();
	}
	p = id;
	do {
		if (p < &id[NCPS])
			*p++ = c;
	} while (ctype[c=get()] & ~(SPACE|ILL));
	unget(c);
	while (p < &id[NCPS])
		*p++ = 0;
}

/*)Function	char	getnb()
 *
 *	The function getnb() scans the current assembler-source
 *	text line returning the first character not a SPACE or TAB.
 *
 *	local variables:
 *		int	c		current character from
 *					assembler-source text line
 *
 *	global variables:
 *		none
 *
 *	called functions:
 *		char	get()		aslex.c
 *
 *	side effects:
 *		use of get() updates the global pointer ip, the position
 *		in the current assembler-source text line
 */

char
getnb()
{
	register c;

	while ((c=get()) == ' ' || c == '\t')
		;
	return (c);
}

/*)Function	char	get()
 *
 *	The function get() returns the next character in the
 *	assembler-source text line, at the end of the line a
 *	NULL character is returned.
 *
 *	local variables:
 *		int	c		current character from
 *					assembler-source text line
 *
 *	global variables:
 *		char *	ip		pointer into the current
 *					assembler-source text line
 *
 *	called functions:
 *		none
 *
 *	side effects:
 *		updates ip to the next character position in the
 *		assembler-source text line.  If ip is at the end of the
 *		line, ip is not updated.
 */

char
get()
{
	register c;

	if ((c = *ip) != 0)
		++ip;
	return (c);
}

/*)Function	VOID	unget(c)
 *
 *		int	c		value of last character read from
 *					assembler-source text line
 *
 *	If (c) is not a NULL character then the global pointer ip
 *	is updated to point to the preceeding character in the
 *	assembler-source text line.
 *
 *	NOTE:	This function does not push the character (c)
 *		back into the assembler-source text line, only
 *		the pointer ip is changed.
 *
 *	local variables:
 *		int	c		last character read from
 *					assembler-source text line
 *
 *	global variables:
 *		char *	ip		position into the current
 *					assembler-source text line
 *
 *	called functions:
 *		none
 *
 *	side effects:
 *		ip decremented by 1 character position
 */

VOID
unget(c)
{
	if (c)
		if (ip != ib)
			--ip;
}

/*)Function	int	getmap(d)
 *
 *		int	d		value to compare with the
 *					assembler-source text line character
 *
 *	The function getmap() converts the 'C' style characters \b, \f,
 *	\n, \r, and \t to their equivalent ascii values and also
 *	converts 'C' style octal constants '\123' to their equivalent
 *	numeric values.  If the first character is equivalent to (d) then
 *	a (-1) is returned, if the end of the line is detected then
 *	a 'q' error terminates the parse for this line, or if the first
 *	character is not a \ then the character value is returned.
 *
 *	local variables:
 *		int	c		value of character from the
 *					assembler-source text line
 *		int	n		looping counter
 *		int	v		current value of numeric conversion
 *
 *	global variables:
 *		none
 *
 *	called functions:
 *		char	get()		aslex.c
 *
 *	side effects:
 *		use of get() updates the global pointer ip the position
 *		in the current assembler-source text line
 */

int
getmap(d)
{
	register c, n, v;

	if ((c=get()) == '\0')
		qerr();
	if (c == d)
		return (-1);
	if (c == '\\') {
		c = get();
		switch (c) {

		case 'b':
			c = '\b';
			break;

		case 'f':
			c = '\f';
			break;

		case 'n':
			c = '\n';
			break;

		case 'r':
			c = '\r';
			break;

		case 't':
			c = '\t';
			break;

		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
			n = 0;
			v = 0;
			while (++n<=3 && c>='0' && c<='7') {
				v = (v<<3) + c - '0';
				c = get();
			}
			unget(c);
			c = v;
			break;
		}
	}
	return (c);
}

/*)Function	int	getline()
 *
 *	The function getline() reads a line of assembler-source text
 *	from an assembly source text file or an include file.
 *	Lines of text are processed from assembler-source files until
 *	all files have been read.  If an include file is opened then
 *	lines of text are read from the include file (or nested
 *	include file) until the end of the include file is found.
 *	The input text line is copied into the global string ib[]
 *	and converted to a NULL terminated string.  The function
 *	getline() returns a (1) after succesfully reading a line
 *	or a (0) if all files have been read.
 *
 *	local variables:
 *		int	i		string length
 *
 *	global variables:
 *		char	ib[]		string buffer containing
 *					assembler-source text line
 *		char	ifp[]		array of file handles for
 *					include files
 *		int	incfil		index for ifp[] specifies
 *					active include file
 *		int	incline[]	array of include file
 *					line numbers
 *		char	sfp[]		array of file handles for
 *					assembler source files
 *		int	cfile		index for sfp[] specifies
 *					active source file
 *		int	srcline[]	array of source file
 *					line numbers
 *		int	inpfil		maximum input file index
 *
 *	called functions:
 *		int	fclose()	c-library
 *		char *	fgets()		c-library
 *		int	strlen()	c-library
 *
 *	side effects:
 *		include file will be closed at detection of end of file.
 *		the next sequential source file may be selected.
 *		the global file indexes incfil or cfile may be changed.
 *		The respective source line or include line counter
 *		will be updated.
 */

int
getline()
{
register i;

loop:	if (incfil >= 0) {
		if (fgets(ib, sizeof ib, ifp[incfil]) == NULL) {
#ifdef SDK
			fclose(ifp[incfil]);
			ifp[incfil--] = NULL;
#else /* SDK */
			fclose(ifp[incfil--]);
#endif /* SDK */
			lop = NLPP;
			goto loop;
		} else {
			++incline[incfil];
		}
	} else {
		if (fgets(ib, sizeof ib, sfp[cfile]) == NULL) {
			if (++cfile <= inpfil) {
				srcline[cfile] = 0;
				goto loop;
			}
			return (0);
		} else {
			++srcline[cfile];
		}
	}
	i = strlen(ib) - 1;
	if (ib[i] == '\n')
		ib[i] = 0;
	return (1);
}

/*)Function	int	more()
 *
 *	The function more() scans the assembler-source text line
 *	skipping white space (SPACES and TABS) and returns a (0)
 *	if the end of the line or a comment delimeter (;) is found,
 *	or a (1) if their are additional characters in the line.
 *
 *	local variables:
 *		int	c		next character from the
 *					assembler-source text line
 *
 *	global variables:
 *		none
 *
 *	called functions:
 *		char	getnb()		aslex.c
 *		VOID	unget()		aslex.c
 *
 *	side effects:
 *		use of getnb() and unget() updates the global pointer ip
 *		the position in the current assembler-source text line
 */

int
more()
{
	register c;

	c = getnb();
	unget(c);
	return( (c == '\0' || c == ';') ? 0 : 1 );
}

/*)Function	char	endline()
 *
 *	The function endline() scans the assembler-source text line
 *	skipping white space (SPACES and TABS) and returns the next
 *	character or a (0) if the end of the line is found or a
 *	comment delimiter (;) is found.
 *
 *	local variables:
 *		int	c		next character from the
 *					assembler-source text line
 *
 *	global variables:
 *		none
 *
 *	called functions:
 *		char	getnb()		aslex.c
 *
 *	side effects:
 *		use of getnb() updates the global pointer ip the
 *		position in the current assembler-source text line
 */

char
endline()
{
	register c;

	c = getnb();
	return( (c == '\0' || c == ';') ? 0 : c );
}
