/*      @(#)scanner.c   8.1 (Berkeley) 6/6/93   */
/*      $NetBSD: scanner.c,v 1.9 2003/08/07 11:17:29 agc Exp $  */

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Edward Wang at The University of California, Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stdlib.h>

#include "defs.h"
#include "token.h"
#include "context.h"
#include "window_string.h"

int     s_getc(void);
int     s_gettok1(void);
int     s_ungetc(int);

int
s_getc(void)
{
        int c;

        switch (cx.x_type) {
        case X_FILE:
                c = getc(cx.x_fp);
                if (cx.x_bol && c != EOF) {
                        cx.x_bol = 0;
                        cx.x_lineno++;
                }
                if (c == '\n')
                        cx.x_bol = 1;
                return c;
        case X_BUF:
                if (*cx.x_bufp != 0)
                        return *cx.x_bufp++ & 0xff;
                else
                        return EOF;
        }
        /*NOTREACHED*/
        return(0);              /* XXX: placate gcc */
}

int
s_ungetc(int c)
{
        if (c == EOF)
                return EOF;
        switch (cx.x_type) {
        case X_FILE:
                cx.x_bol = 0;
                return ungetc(c, cx.x_fp);
        case X_BUF:
                if (cx.x_bufp > cx.x_buf)
                        return *--cx.x_bufp = c;
                else
                        return EOF;
        }
        /*NOTREACHED*/
        return(0);              /* XXX: placate gcc */
}

int
s_gettok(void)
{
        char buf[100];
        char *p = buf;
        int c;
        int state = 0;

loop:
        c = s_getc();
        switch (state) {
        case 0:
                switch (c) {
                case ' ':
                case '\t':
                        break;
                case '\n':
                case ';':
                        cx.x_token = T_EOL;
                        state = -1;
                        break;
                case '#':
                        state = 1;
                        break;
                case EOF:
                        cx.x_token = T_EOF;
                        state = -1;
                        break;
                case 'a': case 'b': case 'c': case 'd': case 'e':
                case 'f': case 'g': case 'h': case 'i': case 'j':
                case 'k': case 'l': case 'm': case 'n': case 'o':
                case 'p': case 'q': case 'r': case 's': case 't':
                case 'u': case 'v': case 'w': case 'x': case 'y':
                case 'z':
                case 'A': case 'B': case 'C': case 'D': case 'E':
                case 'F': case 'G': case 'H': case 'I': case 'J':
                case 'K': case 'L': case 'M': case 'N': case 'O':
                case 'P': case 'Q': case 'R': case 'S': case 'T':
                case 'U': case 'V': case 'W': case 'X': case 'Y':
                case 'Z':
                case '_': case '.':
                        *p++ = c;
                        state = 2;
                        break;
                case '"':
                        state = 3;
                        break;
                case '\'':
                        state = 4;
                        break;
                case '\\':
                        switch (c = s_gettok1()) {
                        case -1:
                                break;
                        case -2:
                                state = 0;
                                break;
                        default:
                                *p++ = c;
                                state = 2;
                        }
                        break;
                case '0':
                        cx.x_val.v_num = 0;
                        state = 10;
                        break;
                case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        cx.x_val.v_num = c - '0';
                        state = 11;
                        break;
                case '>':
                        state = 20;
                        break;
                case '<':
                        state = 21;
                        break;
                case '=':
                        state = 22;
                        break;
                case '!':
                        state = 23;
                        break;
                case '&':
                        state = 24;
                        break;
                case '|':
                        state = 25;
                        break;
                case '$':
                        state = 26;
                        break;
                case '~':
                        cx.x_token = T_COMP;
                        state = -1;
                        break;
                case '+':
                        cx.x_token = T_PLUS;
                        state = -1;
                        break;
                case '-':
                        cx.x_token = T_MINUS;
                        state = -1;
                        break;
                case '*':
                        cx.x_token = T_MUL;
                        state = -1;
                        break;
                case '/':
                        cx.x_token = T_DIV;
                        state = -1;
                        break;
                case '%':
                        cx.x_token = T_MOD;
                        state = -1;
                        break;
                case '^':
                        cx.x_token = T_XOR;
                        state = -1;
                        break;
                case '(':
                        cx.x_token = T_LP;
                        state = -1;
                        break;
                case ')':
                        cx.x_token = T_RP;
                        state = -1;
                        break;
                case ',':
                        cx.x_token = T_COMMA;
                        state = -1;
                        break;
                case '?':
                        cx.x_token = T_QUEST;
                        state = -1;
                        break;
                case ':':
                        cx.x_token = T_COLON;
                        state = -1;
                        break;
                case '[':
                        cx.x_token = T_LB;
                        state = -1;
                        break;
                case ']':
                        cx.x_token = T_RB;
                        state = -1;
                        break;
                default:
                        cx.x_val.v_num = c;
                        cx.x_token = T_CHAR;
                        state = -1;
                        break;
                }
                break;
        case 1:                         /* got # */
                if (c == '\n' || c == EOF) {
                        (void) s_ungetc(c);
                        state = 0;
                }
                break;
        case 2:                         /* unquoted string */
                switch (c) {
                case 'a': case 'b': case 'c': case 'd': case 'e':
                case 'f': case 'g': case 'h': case 'i': case 'j':
                case 'k': case 'l': case 'm': case 'n': case 'o':
                case 'p': case 'q': case 'r': case 's': case 't':
                case 'u': case 'v': case 'w': case 'x': case 'y':
                case 'z':
                case 'A': case 'B': case 'C': case 'D': case 'E':
                case 'F': case 'G': case 'H': case 'I': case 'J':
                case 'K': case 'L': case 'M': case 'N': case 'O':
                case 'P': case 'Q': case 'R': case 'S': case 'T':
                case 'U': case 'V': case 'W': case 'X': case 'Y':
                case 'Z':
                case '_': case '.':
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        if (p < buf + sizeof buf - 1)
                                *p++ = c;
                        break;
                case '"':
                        state = 3;
                        break;
                case '\'':
                        state = 4;
                        break;
                case '\\':
                        switch (c = s_gettok1()) {
                        case -2:
                                (void) s_ungetc(' ');
                        case -1:
                                break;
                        default:
                                if (p < buf + sizeof buf - 1)
                                        *p++ = c;
                        }
                        break;
                default:
                        (void) s_ungetc(c);
                        /* FALLTHROUGH */
                case EOF:
                        *p = 0;
                        cx.x_token = T_STR;
                        switch (*buf) {
                        case 'i':
                                if (buf[1] == 'f' && buf[2] == 0)
                                        cx.x_token = T_IF;
                                break;
                        case 't':
                                if (buf[1] == 'h' && buf[2] == 'e'
                                    && buf[3] == 'n' && buf[4] == 0)
                                        cx.x_token = T_THEN;
                                break;
                        case 'e':
                                if (buf[1] == 'n' && buf[2] == 'd'
                                    && buf[3] == 'i' && buf[4] == 'f'
                                    && buf[5] == 0)
                                        cx.x_token = T_ENDIF;
                                else {
                                        if (buf[1] == 'l' && buf[2] == 's') {
                                                if (buf[3] == 'i'
                                                &&  buf[4] == 'f'
                                                &&  buf[5] == 0)
                                                        cx.x_token = T_ELSIF;
                                                else {
                                                        if (buf[3] == 'e'
                                                        && buf[4] == 0)
                                                                cx.x_token =
                                                                    T_ELSE;
                                                }
                                        }
                                }
                                break;
                        }
                        if (cx.x_token == T_STR
                            && (cx.x_val.v_str = str_cpy(buf)) == 0) {
                                p_memerror();
                                cx.x_token = T_EOF;
                        }
                        state = -1;
                        break;
                }
                break;
        case 3:                         /* " quoted string */
                switch (c) {
                case '\n':
                        (void) s_ungetc(c);
                        /* FALLTHROUGH */
                case EOF:
                case '"':
                        state = 2;
                        break;
                case '\\':
                        switch (c = s_gettok1()) {
                        case -1:
                        case -2:        /* newlines are invisible */
                                break;
                        default:
                                if (p < buf + sizeof buf - 1)
                                        *p++ = c;
                        }
                        break;
                default:
                        if (p < buf + sizeof buf - 1)
                                *p++ = c;
                        break;
                }
                break;
        case 4:                         /* ' quoted string */
                switch (c) {
                case '\n':
                        (void) s_ungetc(c);
                        /* FALLTHROUGH */
                case EOF:
                case '\'':
                        state = 2;
                        break;
                case '\\':
                        switch (c = s_gettok1()) {
                        case -1:
                        case -2:        /* newlines are invisible */
                                break;
                        default:
                                if (p < buf + sizeof buf - 1)
                                        *p++ = c;
                        }
                        break;
                default:
                        if (p < buf + sizeof buf - 1)
                                *p++ = c;
                        break;
                }
                break;
        case 10:                        /* got 0 */
                switch (c) {
                case 'x':
                case 'X':
                        cx.x_val.v_num = 0;
                        state = 12;
                        break;
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7':
                        cx.x_val.v_num = c - '0';
                        state = 13;
                        break;
                case '8': case '9':
                        cx.x_val.v_num = c - '0';
                        state = 11;
                        break;
                default:
                        (void) s_ungetc(c);
                        state = -1;
                        cx.x_token = T_NUM;
                }
                break;
        case 11:                        /* decimal number */
                switch (c) {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        cx.x_val.v_num = cx.x_val.v_num * 10 + c - '0';
                        break;
                default:
                        (void) s_ungetc(c);
                        state = -1;
                        cx.x_token = T_NUM;
                }
                break;
        case 12:                        /* hex number */
                switch (c) {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        cx.x_val.v_num = cx.x_val.v_num * 16 + c - '0';
                        break;
                case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
                        cx.x_val.v_num = cx.x_val.v_num * 16 + c - 'a' + 10;
                        break;
                case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
                        cx.x_val.v_num = cx.x_val.v_num * 16 + c - 'A' + 10;
                        break;
                default:
                        (void) s_ungetc(c);
                        state = -1;
                        cx.x_token = T_NUM;
                }
                break;
        case 13:                        /* octal number */
                switch (c) {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7':
                        cx.x_val.v_num = cx.x_val.v_num * 8 + c - '0';
                        break;
                default:
                        (void) s_ungetc(c);
                        state = -1;
                        cx.x_token = T_NUM;
                }
                break;
        case 20:                        /* got > */
                switch (c) {
                case '=':
                        cx.x_token = T_GE;
                        state = -1;
                        break;
                case '>':
                        cx.x_token = T_RS;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_GT;
                        state = -1;
                }
                break;
        case 21:                        /* got < */
                switch (c) {
                case '=':
                        cx.x_token = T_LE;
                        state = -1;
                        break;
                case '<':
                        cx.x_token = T_LS;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_LT;
                        state = -1;
                }
                break;
        case 22:                        /* got = */
                switch (c) {
                case '=':
                        cx.x_token = T_EQ;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_ASSIGN;
                        state = -1;
                }
                break;
        case 23:                        /* got ! */
                switch (c) {
                case '=':
                        cx.x_token = T_NE;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_NOT;
                        state = -1;
                }
                break;
        case 24:                        /* got & */
                switch (c) {
                case '&':
                        cx.x_token = T_ANDAND;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_AND;
                        state = -1;
                }
                break;
        case 25:                        /* got | */
                switch (c) {
                case '|':
                        cx.x_token = T_OROR;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_OR;
                        state = -1;
                }
                break;
        case 26:                        /* got $ */
                switch (c) {
                case '?':
                        cx.x_token = T_DQ;
                        state = -1;
                        break;
                default:
                        (void) s_ungetc(c);
                        cx.x_token = T_DOLLAR;
                        state = -1;
                }
                break;
        default:
                abort();
        }
        if (state >= 0)
                goto loop;
        return cx.x_token;
}

int
s_gettok1(void)
{
        int c;
        int n;

        c = s_getc();                   /* got \ */
        switch (c) {
        case EOF:
                return -1;
        case '\n':
                return -2;
        case 'b':
                return '\b';
        case 'f':
                return '\f';
        case 'n':
                return '\n';
        case 'r':
                return '\r';
        case 't':
                return '\t';
        default:
                return c;
        case '0': case '1': case '2': case '3': case '4':
        case '5': case '6': case '7':
                break;
        }
        n = c - '0';
        c = s_getc();                   /* got \[0-7] */
        if (c < '0' || c > '7') {
                (void) s_ungetc(c);
                return n;
        }
        n = n * 8 + c - '0';
        c = s_getc();                   /* got \[0-7][0-7] */
        if (c < '0' || c > '7') {
                (void) s_ungetc(c);
                return n;
        }
        return n * 8 + c - '0';
}