/* scan.c - lexical analyser for bcc */

/* Copyright (C) 1992 Bruce Evans */

#define GCH1() do { if (SYMOFCHAR(ch = *++lineptr) == SPECIALCHAR) specialchar(); } while (0)

#include "const.h"
#include "types.h"
#include "input.h"
#include "os.h"
#include "output.h"
#include "sc.h"
#include "sizes.h"
#include "table.h"
#include "type.h"

#undef EXTERN
#define EXTERN
#include "scan.h"

PUBLIC sym_t symofchar[256] =
{
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, WHITESPACE, SPECIALCHAR, BADCHAR,
    WHITESPACE, SPECIALCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,

    WHITESPACE, LOGNOTOP, STRINGCONST, CONTROL,	/*  !"# */
    BADCHAR, MODOP, AMPERSAND, CHARCONST,	/* $%&' */
    LPAREN, RPAREN, STAR, ADDOP,		/* ()*+ */
    COMMA, HYPHEN, FLOATCONST, SLASH,		/* ,-./ */

    INTCONST, INTCONST, INTCONST, INTCONST,	/* 0123 */
    INTCONST, INTCONST, INTCONST, INTCONST,	/* 4567 */
    INTCONST, INTCONST, COLON, SEMICOLON,	/* 89:; */
    LTOP, ASSIGNOP, GTOP, CONDOP,		/* <=>? */

    BADCHAR, IDENT, IDENT, IDENT,		/* @ABC */
    IDENT, IDENT, IDENT, IDENT,			/* DEFG */
    IDENT, IDENT, IDENT, IDENT,			/* HIJK */
    IDENT, IDENT, IDENT, IDENT,			/* LMNO */
    IDENT, IDENT, IDENT, IDENT,			/* PQRS */
    IDENT, IDENT, IDENT, IDENT,			/* TUVW */
    IDENT, IDENT, IDENT, LBRACKET,		/* XYZ[ */
    SPECIALCHAR, RBRACKET, EOROP, IDENT,	/* \]^_ */

    BADCHAR, IDENT, IDENT, IDENT,		/* `abc */
    IDENT, IDENT, IDENT, IDENT,			/* defg */
    IDENT, IDENT, IDENT, IDENT,			/* hijk */
    IDENT, IDENT, IDENT, IDENT,			/* lmno */
    IDENT, IDENT, IDENT, IDENT,			/* pqrs */
    IDENT, IDENT, IDENT, IDENT,			/* tuvw */
    IDENT, IDENT, IDENT, LBRACE,		/* xyz{ */
    OROP, RBRACE, NOTOP, BADCHAR,		/* |}~  */

    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,

    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,

    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,

    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR,
    BADCHAR, BADCHAR, BADCHAR, BADCHAR
};

FORWARD void getident P((void));
FORWARD void intconst P((void));
FORWARD void ppnumber P((void));
PRIVATE void newstringorcharconst P((void));

/* skip white space up to end of line (skip EOL's if in comments) */

PUBLIC void blanks()
{
    register char *reglineptr;

    while (TRUE)
    {
	reglineptr = lineptr;
	while (SYMOFCHAR(*reglineptr) == WHITESPACE)
	    ++reglineptr;
	lineptr = reglineptr;
	if (SYMOFCHAR(ch = *reglineptr) == SPECIALCHAR)
	{
	    specialchar();
	    if (ch == EOL)
		return;
	    if (SYMOFCHAR(ch) == WHITESPACE)
		continue;
	    reglineptr = lineptr;
	}
	if (*reglineptr != '/')
	    return;
	if (SYMOFCHAR(*(reglineptr + 1)) == SPECIALCHAR)
	{
	    ch = *(lineptr = reglineptr + 1);
	    specialchar();
	    ch = *(reglineptr = --lineptr) = '/';	/* pushback */
	}
	if (*(reglineptr + 1) != '*')
	    return;
	gch1();
	skipcomment();
    }
}

PUBLIC void cppscan()
{
    while (TRUE)
    {
	switch (SYMOFCHAR(ch))
	{
	case CHARCONST:
	case STRINGCONST:
	    stringorcharconst();
	    *charptr = 0;	/* room reserved */
	    outstr(constant.value.s);	/* XXX - embedded null would kill it */
	    charptr = constant.value.s;
	    break;
	case CONTROL:
	    gch1();
	    if (maclevel != 0)
	    {
		error("# in a macro: not preprocessed");	/* XXX? */
		break;
	    }
	    else
	    {
		cppmode = FALSE;
		docontrol();
		cppmode = TRUE;
		break;
	    }
	case SLASH:
	    gch1();
	    if (ch == '*')
	    {
		skipcomment();
		break;
	    }
	    outbyte('/');
	    break;
	case FLOATCONST:
	    gch1();
	    if (SYMOFCHAR(ch) == INTCONST)
	    {
		--lineptr;
		ch = '.';	/* pushback */
		ppnumber();
		outstr(constant.value.s);
		charptr = constant.value.s;
	    }
	    else
		outbyte('.');
	    break;
	case IDENT:
	    getident();
	    if ((gsymptr = findlorg(gsname)) != NULL)
	    {
		if (gsymptr->flags == DEFINITION)
		{
		    entermac();
		    break;
		}
	    }
	    outstr(gsname);
	    break;
	case INTCONST:
	    ppnumber();
	    outstr(constant.value.s);
	    charptr = constant.value.s;
	    break;
	case SPECIALCHAR:
	    specialchar();	/* XXX - this is necessary because entermac
				 * and skipeol can leave lineptr at a special
				 * char although GCH1 cannot.  entermac would
				 * be easy to fix, but too many places already
				 * have to handle the extra work after skipeol
				 * for other reasons.
				 */
	    if (ch == EOL)
	    {
		skipeol();
		if (eof)
		    return;
		break;
	    }
#ifdef COEOL
	    if (ch == COEOL)
	    {
		gch1();
		break;
	    }
#endif
	    if (SYMOFCHAR(ch) != SPECIALCHAR)
		break;		/* specialchar advanced the input */
	    /* must be '\\' */
	default:
	    OUTBYTE(ch);
	    GCH1();
	    break;
	}
    }
}

PUBLIC void eofin(message)
char *message;
{
    error2error("end of file in ", message);
}

/* get identifier in gsname == gs2name + 2 */

PRIVATE void getident()
{
    register int c;
    register char *idptr;
    register int length;
    register char *reglineptr;

    idptr = gsname;
    length = NAMESIZE;
    reglineptr = lineptr;
    c = ch;
more:
    do
    {
	*idptr++ = c;
	c = (unsigned char) *++reglineptr;
    }
    while (symofchar[c] <= MAXIDSYM && --length != 0);
    ch = c;
    *idptr = 0;
    lineptr = reglineptr;
    if (symofchar[c] == SPECIALCHAR)
    {
	specialchar();
	if (SYMOFCHAR(ch) <= MAXIDSYM && length != 0)
	{
	    reglineptr = lineptr;
	    c = ch;
	    goto more;
	}
    }
}

/* return nonzero if at an identifier */

PUBLIC bool_pt isident()
{
    if (SYMOFCHAR(ch) != IDENT)
	return FALSE;
    getident();
    return TRUE;
}

PRIVATE void intconst()
{
    fastin_t base;
    fastin_t digit;
    register char *digptr;
    fastin_t lcount;
    fastin_t ucount;
    bool_t dflag;

    ppnumber();
    digptr = charptr = constant.value.s;
    if (*digptr == '0')
    {
	if (digptr[1] != 'x' && digptr[1] != 'X')
	    base = 8;
	else
	{
	    base = 16;
	    digptr += 2;
	}
    }
    else
	base = 10;
    dflag = FALSE;
    if (*digptr == 0)
	error("constant has no digits");
    if (base != 16)
    {
	while (SYMOFCHAR(*digptr) == INTCONST)
	    ++digptr;
	if (*digptr == '.')
	{
	    dflag = TRUE;
	    ++digptr;
	    while (SYMOFCHAR(*digptr) == INTCONST)
		++digptr;
	}
	if (*digptr == 'E' || *digptr == 'e')
	{
	    dflag = TRUE;
	    ++digptr;
	    if (*digptr == '+' || *digptr == '-')
		++digptr;
	    if (SYMOFCHAR(*digptr) != INTCONST)
		error("exponent has no digits");
	    while (SYMOFCHAR(*digptr) == INTCONST)
		++digptr;
	}
    }
    if (dflag)
    {
	constant.type = dtype;
	digit = *digptr;
	*digptr = 0;
	constant.value.d = atof(constant.value.s);
	*digptr = digit;
	if (digit == 'F' || digit == 'f')
	{
	    ++digptr;
	    constant.type = fltype;
	    constant.value.d = (float) constant.value.d;
	}
	sym = FLOATCONST;
	if (*digptr != 0)
	    error("junk at end of floating point constant");
	return;
    }
    if (base != 16)
	digptr = constant.value.s;
    constant.value.v = 0;
    while (*digptr >= '0')
    {
	digit = *digptr;
	if (digit > '9')
	{
	    if (base != 16)
		break;
	    if (digit >= 'a' && digit <= 'f')
		digit = digit + (-'a' + '0' + 10);
	    else if (digit >= 'A' && digit <= 'F')
		digit = digit + (-'A' + '0' + 10);
	    else
		break;
	}
	constant.value.v = base * constant.value.v + (digit - '0');
	++digptr;
    }
    ucount = lcount = 0;
    while (TRUE)
    {
	if (*digptr == 'L' || *digptr == 'l')
	    ++lcount;
	else if (*digptr == 'U' || *digptr == 'u')
	    ++ucount;
	else
	    break;
	++digptr;
    }
    if (lcount > 1)
	error("more than one 'L' in integer constant");
    if (ucount > 1)
	error("more than one 'U' in integer constant");
    if (constant.value.v <= maxintto && lcount == 0 && ucount == 0)
	constant.type = itype;
    else if (constant.value.v <= maxuintto && lcount == 0
	     && (base != 10 || ucount != 0))
	constant.type = uitype;
    else if (constant.value.v <= maxlongto && ucount == 0)
	constant.type = ltype;
    else
	constant.type = ultype;
    if (*digptr != 0)
	error("junk at end of integer constant");
}

PUBLIC void nextsym()
{
    static char lastch;
    register char *reglineptr;

    while (TRUE)		/* exit with short, fast returns */
    {
	reglineptr = lineptr;
	while ((sym = SYMOFCHAR(*reglineptr)) == WHITESPACE)
	    ++reglineptr;
	lastch = *reglineptr;
	if (SYMOFCHAR(ch = *(lineptr = reglineptr + 1)) == SPECIALCHAR
	    && sym != SPECIALCHAR)
	    specialchar();
	switch (sym)
	{
	case CHARCONST:
	    --lineptr;
	    ch = lastch;	/* pushback */
	    stringorcharconst();
	    newstringorcharconst();
	    if (charptr == constant.value.s)
	    {
		charptr = constant.value.s;
		error("empty character constant");
		constant.value.v = 0;
	    }
	    else
	    {
		if (charptr != constant.value.s + 1)
		    error("character constant too long");
		charptr = constant.value.s;
		constant.value.v = *constant.value.s & CHMASKTO;
	    }
	    constant.type = itype;
	    return;
	case CONTROL:
	    if (maclevel != 0)
	    {
		error("# in a macro: not preprocessed");	/* XXX? */
		return;
	    }
	    else
	    {
		docontrol();
		break;
	    }
	case FLOATCONST:
	    if (SYMOFCHAR(ch) == INTCONST)
	    {
		--lineptr;
		ch = lastch;
		intconst();
	    }
	    else
		sym = STRUCELTOP;
	    return;
	case IDENT:
	    --lineptr;
	    ch = lastch;
	    getident();
	    if ((gsymptr = findlorg(gsname)) != NULL)
	    {
		if (gsymptr->flags == DEFINITION)
		{
		    entermac();
		    break;
		}
		if (gsymptr->flags == KEYWORD)
		    sym = gsymptr->offset.offsym;
	    }
	    return;
	case INTCONST:
	    --lineptr;
	    ch = lastch;
	    intconst();
	    return;
	case SPECIALCHAR:
	    ch = *(lineptr = reglineptr);
	    specialchar();
	    if (ch == EOL)
	    {
		if (incppexpr)
		{
		    sym = SEMICOLON;
		    return;
		}
		skipeol();
		if (eof)
		{
		    sym = EOFSYM;
		    return;
		}
		break;
	    }
	    if (SYMOFCHAR(ch) != SPECIALCHAR)
		break;
	    gch1();
	    /* fall through to BADCHAR case */
	case BADCHAR:
	    error("illegal character");
	    break;
	case STRINGCONST:
	    --lineptr;
	    ch = lastch;	/* pushback */
	    stringorcharconst();
	    newstringorcharconst();
#ifdef TS
	    ts_n_string += charptr - constant.value.s;
#endif
	    return;
	case COLON:		/* could be COLONOP or in label */
	case COMMA:		/* could be COMMAOP or in list */
	case CONDOP:
	case LBRACE:
	case LBRACKET:
	case LPAREN:
	case NOTOP:
	case RBRACE:
	case RBRACKET:
	case RPAREN:
	case SEMICOLON:
	    return;
	case ASSIGNOP:
	    if (ch == '=')
	    {
		sym = EQOP;
		gch1();
	    }
	    return;
	case ADDOP:
	    if (ch == '+')
	    {
		sym = INCSYM;	/* PREINCOP or POSINCOP */
		gch1();
	    }
	    else if (ch == '=')
	    {
		sym = ADDABOP;
		gch1();
	    }
	    return;
	case HYPHEN:		/* NEGOP or SUBOP or decoded below */
	    if (ch == '-')
	    {
		sym = DECSYM;	/* PREDECOP or POSTDECOP */
		gch1();
	    }
	    else if (ch == '=')
	    {
		sym = SUBABOP;
		gch1();
	    }
	    else if (ch == '>')
	    {
		sym = STRUCPTROP;
		gch1();
	    }
	    return;
	case STAR:		/* INDIRECTOP or MULOP or as below */
	    if (ch == '=')
	    {
		sym = MULABOP;
		gch1();
	    }
	    return;
	case SLASH:
	    if (ch == '*')
	    {
		skipcomment();
		break;
	    }
	    if (ch == '=')
	    {
		sym = DIVABOP;
		gch1();
	    }
	    else
		sym = DIVOP;
	    return;
	case MODOP:
	    if (ch == '=')
	    {
		sym = MODABOP;
		gch1();
	    }
	    return;
	case LTOP:
	    if (ch == '=')
	    {
		sym = LEOP;
		gch1();
	    }
	    else if (ch == '<')
	    {
		gch1();
		if (ch == '=')
		{
		    sym = SLABOP;
		    gch1();
		}
		else
		{
		    sym = SLOP;
		}
	    }
	    return;
	case GTOP:
	    if (ch == '=')
	    {
		sym = GEOP;
		gch1();
	    }
	    else if (ch == '>')
	    {
		gch1();
		if (ch == '=')
		{
		    sym = SRABOP;
		    gch1();
		}
		else
		{
		    sym = SROP;
		}
	    }
	    return;
	case AMPERSAND:		/* ADDRESSOP or ANDOP or as below */
	    if (ch == '&')
	    {
		sym = LOGANDOP;
		gch1();
	    }
	    else if (ch == '=')
	    {
		sym = ANDABOP;
		gch1();
	    }
	    return;
	case EOROP:
	    if (ch == '=')
	    {
		sym = EORABOP;
		gch1();
	    }
	    return;
	case OROP:
	    if (ch == '|')
	    {
		sym = LOGOROP;
		gch1();
	    }
	    else if (ch == '=')
	    {
		sym = ORABOP;
		gch1();
	    }
	    return;
	case LOGNOTOP:
	    if (ch == '=')
	    {
		sym = NEOP;
		gch1();
	    }
	    return;
	}
    }
}

PRIVATE void ppnumber()
{
    constant.value.s = charptr;
    while (TRUE)
    {
	if (charptr >= char1top)
	    constant.value.s = growobject(constant.value.s, 2);
	*charptr++ = ch;
	if (ch == 'E' || ch == 'e')
	{
	    gch1();
	    if (ch == '+' || ch == '-')
		continue;
	}
	else
	    GCH1();
	if (SYMOFCHAR(ch) > MAXPPNUMSYM)
	    break;
    }
    *charptr = 0;
}

PUBLIC void stringorcharconst()
{
    char terminator;

    constant.value.s = charptr;
    terminator = ch;
    while (TRUE)
    {
	if (charptr >= char3top)
	    constant.value.s = growobject(constant.value.s, 4);
	*charptr++ = ch;
	if (ch == '\\')
	{
	    gch1();
	    if (ch == EOL)
	    {
		if (!orig_cppmode)
		    eofin("escape sequence");
		break;
	    }
	    *charptr++ = ch;
	}
	GCH1();
	if (ch == EOL)
	{
	    if (!orig_cppmode)
		error(terminator == '"' ? "end of line in string constant"
		      : "end of line in character constant");
	    break;
	}
	if (ch == terminator)
	{
	    *charptr++ = terminator;
	    gch1();
	    break;
	}
    }
}

PRIVATE void newstringorcharconst()
{
    char *endinptr;
    int escvalue;
    fastin_t maxdigits;
    register char *inptr;
    register char *outptr;

    outptr = constant.value.s;
    inptr = charptr - 1;
    if (inptr == outptr || *inptr != *outptr)
	endinptr = charptr;	/* not properly terminated */
    else
	endinptr = inptr;
    inptr = outptr + 1;
    while (inptr != endinptr)
    {
	if (*inptr == '\\')
	{
	    if (++inptr == endinptr)
		break;		/* error reported already */
	    if (*inptr >= '0' && *inptr < '8')
	    {
		escvalue = 0;
		maxdigits = 3;
		do
		{
		    escvalue = 8 * escvalue + *inptr - '0';
		    ++inptr;
		}
		while (--maxdigits != 0 && *inptr >= '0' && *inptr < '8');
		--inptr;
		*outptr++ = escvalue;
	    }
	    else switch (*inptr)
	    {
	    case '"':
	    case '\'':
	    case '\\':
		*outptr++ = *inptr;
		break;
	    case 'a':
		*outptr++ = 7;
		break;
	    case 'b':
		*outptr++ = 8;
		break;
	    case 'f':
		*outptr++ = 12;
		break;
	    case 'n':
		*outptr++ = EOLTO;
		break;
	    case 'r':
		*outptr++ = 13;
		break;
	    case 't':
		*outptr++ = 9;
		break;
	    case 'v':
		*outptr++ = 11;
		break;
	    default:
		error("%wnonstandard escape sequence");
		*outptr++ = *inptr;
		break;
	    }
	}
	else
	    *outptr++ = *inptr;
	++inptr;
    }
    charptr = outptr;
}