/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)lexi.c	5.4 (Berkeley) 9/10/85";
#endif not lint

/*-
 *
 *			  Copyright (C) 1976
 *				by the
 *			  Board of Trustees
 *				of the
 *			University of Illinois
 *
 *			 All rights reserved
 *
 *
 * NAME:
 *	lexi
 *
 * FUNCTION:
 *	This is the token scanner for indent
 *
 * ALGORITHM:
 *	1) Strip off intervening blanks and/or tabs.
 *	2) If it is an alphanumeric token, move it to the token buffer "token".
 *	   Check if it is a special reserved word that indent will want to
 *	   know about.
 *	3) Non-alphanumeric tokens are handled with a big switch statement.  A
 *	   flag is kept to remember if the last token was a "unary delimiter",
 *	   which forces a following operator to be unary as opposed to binary.
 *
 * PARAMETERS:
 *	None
 *
 * RETURNS:
 *	An integer code indicating the type of token scanned.
 *
 * GLOBALS:
 *	buf_ptr =
 *	had_eof
 *	ps.last_u_d =	Set to true iff this token is a "unary delimiter"
 *
 * CALLS:
 *	fill_buffer
 *	printf (lib)
 *
 * CALLED BY:
 *	main
 *
 * NOTES:
 *	Start of comment is passed back so that the comment can be scanned by
 *	pr_comment.
 *
 *	Strings and character literals are returned just like identifiers.
 *
 * HISTORY:
 *	initial coding 	November 1976	D A Willcox of CAC
 *	1/7/77		D A Willcox of CAC	Fix to provide proper handling
 *						of "int a -1;"
 *
 */

/*
 * Here we have the token scanner for indent.  It scans off one token and
 * puts it in the global variable "token".  It returns a code, indicating
 * the type of token scanned. 
 */

#include "indent_globs.h";
#include "indent_codes.h";
#include "ctype.h"

#define alphanum 1
#define opchar 3

struct templ {
    char       *rwd;
    int         rwcode;
};

struct templ specials[100] =
{
    "switch", 1,
    "case", 2,
    "break", 0,
    "struct", 3,
    "union", 3,
    "enum", 3,
    "default", 2,
    "int", 4,
    "char", 4,
    "float", 4,
    "double", 4,
    "long", 4,
    "short", 4,
    "typdef", 4,
    "unsigned", 4,
    "register", 4,
    "static", 4,
    "global", 4,
    "extern", 4,
    "void", 4,
    "goto", 0,
    "return", 0,
    "if", 5,
    "while", 5,
    "for", 5,
    "else", 6,
    "do", 6,
    "sizeof", 7,
    0, 0
};

char        chartype[128] =
{				/* this is used to facilitate the decision
				 * of what type (alphanumeric, operator)
				 * each character is */
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 3, 0, 0, 0, 3, 3, 0,
    0, 0, 3, 3, 0, 3, 3, 3,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 0, 0, 3, 3, 3, 3,
    0, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 0, 0, 0, 3, 1,
    0, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 0, 3, 0, 3, 0
};




int 
lexi()
{
    register char *tok;		/* local pointer to next char in token */
    int         unary_delim;	/* this is set to 1 if the current token 
				 *
				 * forces a following operator to be unary */
    static int  last_code;	/* the last token type returned */
    static int  l_struct;	/* set to 1 if the last token was 'struct' */
    int         code;		/* internal code to be returned */
    char        qchar;		/* the delimiter character for a string */

    tok = token;		/* point to start of place to save token */
    unary_delim = false;
    ps.col_1 = ps.last_nl;	/* tell world that this token started in
				 * column 1 iff the last thing scanned was
				 * nl */
    ps.last_nl = false;

    while (*buf_ptr == ' ' || *buf_ptr == '\t') {	/* get rid of blanks */
	ps.col_1 = false;	/* leading blanks imply token is not in
				 * column 1 */
	if (++buf_ptr >= buf_end)
	    fill_buffer();
    }

    /* Scan an alphanumeric token.  Note that we must also handle
     * stuff like "1.0e+03" and "7e-6". */
    if (chartype[*buf_ptr & 0177] == alphanum) {	/* we have a character
							 * or number */
	register char *j;	/* used for searching thru list of 
				 * reserved words */
	register struct templ *p;
	register int c;

	do {			/* copy it over */
	    *tok++ = *buf_ptr++;
	    if (buf_ptr >= buf_end)
		fill_buffer();
	} while (chartype[c = *buf_ptr & 0177] == alphanum ||
		isdigit(token[0]) && (c == '+' || c == '-') &&
		(tok[-1] == 'e' || tok[-1] == 'E'));
	*tok++ = '\0';
	while (*buf_ptr == ' ' || *buf_ptr == '\t') {	/* get rid of blanks */
	    if (++buf_ptr >= buf_end)
		fill_buffer();
	}
	ps.its_a_keyword = false;
	ps.sizeof_keyword = false;
	if (l_struct) {		/* if last token was 'struct', then this
				 * token should be treated as a
				 * declaration */
	    l_struct = false;
	    last_code = ident;
	    ps.last_u_d = true;
	    return (decl);
	}
	ps.last_u_d = false;	/* Operator after indentifier is binary */
	last_code = ident;	/* Remember that this is the code we will
				 * return */

	/*
	 * This loop will check if the token is a keyword. 
	 */
	for (p = specials; (j = p->rwd) != 0; p++) {
	    tok = token;	/* point at scanned token */
	    if (*j++ != *tok++ || *j++ != *tok++)
		continue;	/* This test depends on the fact that
				 * identifiers are always at least 1
				 * character long (ie. the first two bytes
				 * of the identifier are always
				 * meaningful) */
	    if (tok[-1] == 0)
		break;		/* If its a one-character identifier */
	    while (*tok++ == *j)
		if (*j++ == 0)
		    goto found_keyword;	/* I wish that C had a multi-level
					 * break... */
	}
	if (p->rwd) {		/* we have a keyword */
    found_keyword:
	    ps.its_a_keyword = true;
	    ps.last_u_d = true;
	    switch (p->rwcode) {
		case 1:	/* it is a switch */
		    return (swstmt);
		case 2:	/* a case or default */
		    return (casestmt);

		case 3:	/* a "struct" */
		    if (ps.p_l_follow)
			break;	/* inside parens: cast */
		    l_struct = true;

		    /*
		     * Next time around, we will want to know that we have
		     * had a 'struct' 
		     */
		case 4:	/* one of the declaration keywords */
		    if (ps.p_l_follow) {
			ps.cast_mask |= 1 << ps.p_l_follow;
			break;	/* inside parens: cast */
		    }
		    last_code = decl;
		    return (decl);

		case 5:	/* if, while, for */
		    return (sp_paren);

		case 6:	/* do, else */
		    return (sp_nparen);

		case 7:
		    ps.sizeof_keyword = true;
		default:	/* all others are treated like any other
				 * identifier */
		    return (ident);
	    }			/* end of switch */
	}			/* end of if (found_it) */
	if (*buf_ptr == '(' && ps.tos <= 1 && ps.ind_level == 0
	    && (buf_ptr[1] != ')' || buf_ptr[2] != ';')) {
	    strncpy(ps.procname, token, sizeof ps.procname - 1);
	    ps.in_parameter_declaration = 1;
	}

	/*
	 * The following hack attempts to guess whether or not the current
	 * token is in fact a declaration keyword -- one that has been
	 * typedefd 
	 */
	if (((*buf_ptr == '*' && buf_ptr[1] != '=') || isalpha(*buf_ptr))
	    && !ps.p_l_follow
	    && (ps.last_token == rparen || ps.last_token == semicolon ||
		ps.last_token == decl ||
		ps.last_token == lbrace || ps.last_token == rbrace)) {
	    ps.its_a_keyword = true;
	    ps.last_u_d = true;
	    last_code = decl;
	    return decl;
	}
	if (last_code == decl)	/* if this is a declared variable, then
				 * following sign is unary */
	    ps.last_u_d = true;	/* will make "int a -1" work */
	last_code = ident;
	return (ident);		/* the ident is not in the list */
    }				/* end of procesing for alpanum character */
    /* Scan a non-alphanumeric token */

    *tok++ = *buf_ptr;		/* if it is only a one-character token, it
				 * is moved here */
    *tok = '\0';
    if (++buf_ptr >= buf_end)
	fill_buffer();

    switch (*token) {
	case '\n':
	    unary_delim = ps.last_u_d;
	    ps.last_nl = true;	/* remember that we just had a newline */
	    code = (had_eof ? 0 : newline);

	    /*
	     * if data has been exausted, the newline is a dummy, and we
	     * should return code to stop 
	     */
	    break;

	case '\'':		/* start of quoted character */
	case '"':		/* start of string */
	    qchar = *token;
	    if (troff) {
		tok[-1] = '`';
		if (qchar == '"')
		    *tok++ = '`';
		*tok++ = BACKSLASH;
		*tok++ = 'f';
		*tok++ = 'L';
	    }
	    do {		/* copy the string */
		while (1) {	/* move one character or [/<char>]<char> */
		    if (*buf_ptr == '\n') {
			printf("%d: Unterminated literal\n", line_no);
			goto stop_lit;
		    }
		    *tok = *buf_ptr++;
		    if (buf_ptr >= buf_end)
			fill_buffer();
		    if (had_eof || ((tok - token) > (bufsize - 2))) {
			printf("Unterminated literal\n");
			++tok;
			goto stop_lit;
			/* get outof literal copying loop */
		    }
		    if (*tok == BACKSLASH) {	/* if escape, copy extra
						 * char */
			if (*buf_ptr == '\n')	/* check for escaped
						 * newline */
			    ++line_no;
			if (troff) {
			    *++tok = BACKSLASH;
			    if (*buf_ptr == BACKSLASH)
				*++tok = BACKSLASH;
			}
			*++tok = *buf_ptr++;
			++tok;	/* we must increment this again because we
				 * copied two chars */
			if (buf_ptr >= buf_end)
			    fill_buffer();
		    }
		    else
			break;	/* we copied one character */
		}		/* end of while (1) */
	    } while (*tok++ != qchar);
	    if (troff) {
		tok[-1] = BACKSLASH;
		*tok++ = 'f';
		*tok++ = 'R';
		*tok++ = '\'';
		if (qchar == '"')
		    *tok++ = '\'';
	    }
    stop_lit:
	    code = ident;
	    break;

	case ('('):
	case ('['):
	    unary_delim = true;
	    code = lparen;
	    break;

	case (')'):
	case (']'):
	    code = rparen;
	    break;

	case '#':
	    unary_delim = ps.last_u_d;
	    code = preesc;
	    break;

	case '?':
	    unary_delim = true;
	    code = question;
	    break;

	case (':'):
	    code = colon;
	    unary_delim = true;
	    break;

	case (';'):
	    unary_delim = true;
	    code = semicolon;
	    break;

	case ('{'):
	    unary_delim = true;

	    /*
	     * if (ps.in_or_st) ps.block_init = 1; 
	     */
	    code = ps.block_init ? lparen : lbrace;
	    break;

	case ('}'):
	    unary_delim = true;
	    code = ps.block_init ? rparen : rbrace;
	    break;

	case 014:		/* a form feed */
	    unary_delim = ps.last_u_d;
	    ps.last_nl = true;	/* remember this so we can set 'ps.col_1'
				 * right */
	    code = form_feed;
	    break;

	case (','):
	    unary_delim = true;
	    code = comma;
	    break;

	case '.':
	    unary_delim = false;
	    code = period;
	    break;

	case '-':
	case '+':		/* check for -, +, --, ++ */
	    code = (ps.last_u_d ? unary_op : binary_op);
	    unary_delim = true;

	    if (*buf_ptr == token[0]) {
		/* check for doubled character */
		*tok++ = *buf_ptr++;
		/* buffer overflow will be checked at end of loop */
		if (last_code == ident || last_code == rparen) {
		    code = (ps.last_u_d ? unary_op : postop);
		    /* check for following ++ or -- */
		    unary_delim = false;
		}
	    }
	    else if (*buf_ptr == '=')
		/* check for operator += */
		*tok++ = *buf_ptr++;
	    else if (token[0] == '-' && *buf_ptr == '>') {
		/* check for operator -> */
		*tok++ = *buf_ptr++;
		if (!pointer_as_binop) {
		    code = unary_op;
		    unary_delim = false;
		    ps.want_blank = false;
		}
	    }
	    /* buffer overflow will be checked at end of switch */

	    break;

	case '=':
	    if (ps.in_or_st)
		ps.block_init = 1;
	    if (chartype[*buf_ptr] == opchar) {	/* we have two char
						 * assignment */
		tok[-1] = *buf_ptr++;
		if ((tok[-1] == '<' || tok[-1] == '>') && tok[-1] == *buf_ptr)
		    *tok++ = *buf_ptr++;
		*tok++ = '=';	/* Flip =+ to += */
		*tok = 0;
	    }
	    code = binary_op;
	    unary_delim = true;
	    break;
	    /* can drop thru!!! */

	case '>':
	case '<':
	case '!':		/* ops like <, <<, <=, !=, etc */
	    if (*buf_ptr == '>' || *buf_ptr == '<' || *buf_ptr == '=') {
		*tok++ = *buf_ptr;
		if (++buf_ptr >= buf_end)
		    fill_buffer();
	    }
	    if (*buf_ptr == '=')
		*tok++ = *buf_ptr++;
	    code = (ps.last_u_d ? unary_op : binary_op);
	    unary_delim = true;
	    break;

	default:
	    if (token[0] == '/' && *buf_ptr == '*') {
		/* it is start of comment */
		*tok++ = '*';

		if (++buf_ptr >= buf_end)
		    fill_buffer();

		code = comment;
		unary_delim = ps.last_u_d;
		break;
	    }
	    while (*(tok - 1) == *buf_ptr || *buf_ptr == '=') {
		/* handle ||, &&, etc, and also things as in int *****i */
		*tok++ = *buf_ptr;
		if (++buf_ptr >= buf_end)
		    fill_buffer();
	    }
	    code = (ps.last_u_d ? unary_op : binary_op);
	    unary_delim = true;


    }				/* end of switch */
    if (code != newline) {
	l_struct = false;
	last_code = code;
    }
    if (buf_ptr >= buf_end)	/* check for input buffer empty */
	fill_buffer();
    ps.last_u_d = unary_delim;
    *tok = '\0';		/* null terminate the token */
    return (code);
};

/* Add the given keyword to the keyword table, using val as the keyword type
   */
addkey (key, val)
char       *key;
{
    register struct templ *p = specials;
    while (p->rwd)
	if (p->rwd[0] == key[0] && strcmp(p->rwd, key) == 0)
	    return;
	else
	    p++;
    if (p >= specials + sizeof specials / sizeof specials[0])
	return;			/* For now, table overflows are silently
				   ignored */
    p->rwd = key;
    p->rwcode = val;
    p[1].rwd = 0;
    p[1].rwcode = 0;
    return;
}