/* $OpenBSD: comp_scan.c,v 1.16 2023/10/17 09:52:09 nicm Exp $ */

/****************************************************************************
,* Copyright 2020-2022,2023 Thomas E. Dickey                                *
 * Copyright 1998-2016,2017 Free Software Foundation, Inc.                  *
 *                                                                          *
 * Permission is hereby granted, free of charge, to any person obtaining a  *
 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
 *                                                                          *
 * Except as contained in this notice, the name(s) of the above copyright   *
 * holders shall not be used in advertising or otherwise to promote the     *
 * sale, use or other dealings in this Software without prior written       *
 * authorization.                                                           *
 ****************************************************************************/

/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 *     and: Thomas E. Dickey                        1996 on                 *
 ****************************************************************************/

/*
 *      comp_scan.c --- Lexical scanner for terminfo compiler.
 *
 *      _nc_reset_input()
 *      _nc_get_token()
 *      _nc_panic_mode()
 *      int _nc_syntax;
 *      int _nc_curr_line;
 *      long _nc_curr_file_pos;
 *      long _nc_comment_start;
 *      long _nc_comment_end;
 */

#include <curses.priv.h>

#include <ctype.h>
#include <tic.h>

MODULE_ID("$Id: comp_scan.c,v 1.16 2023/10/17 09:52:09 nicm Exp $")

/*
 * Maximum length of string capability we'll accept before raising an error.
 * Yes, there is a real capability in /etc/termcap this long, an "is".
 */
#define MAXCAPLEN       600

#define iswhite(ch)     (ch == ' '  ||  ch == '\t')

NCURSES_EXPORT_VAR (int) _nc_syntax = 0;         /* termcap or terminfo? */
NCURSES_EXPORT_VAR (int) _nc_strict_bsd = 1;  /* ncurses extended termcap? */
NCURSES_EXPORT_VAR (long) _nc_curr_file_pos = 0; /* file offset of current line */
NCURSES_EXPORT_VAR (long) _nc_comment_start = 0; /* start of comment range before name */
NCURSES_EXPORT_VAR (long) _nc_comment_end = 0;   /* end of comment range before name */
NCURSES_EXPORT_VAR (long) _nc_start_line = 0;    /* start line of current entry */

NCURSES_EXPORT_VAR (struct token) _nc_curr_token =
{
    0, 0, 0
};

/*****************************************************************************
 *
 * Token-grabbing machinery
 *
 *****************************************************************************/

static bool first_column;       /* See 'next_char()' below */
static bool had_newline;
static char separator;          /* capability separator */
static int pushtype;            /* type of pushback token */
static char *pushname;

#if NCURSES_EXT_FUNCS
NCURSES_EXPORT_VAR (bool) _nc_disable_period = FALSE; /* used by tic -a option */
#endif

/*****************************************************************************
 *
 * Character-stream handling
 *
 *****************************************************************************/

#define LEXBUFSIZ       1024

static char *bufptr;            /* otherwise, the input buffer pointer */
static char *bufstart;          /* start of buffer so we can compute offsets */
static FILE *yyin;              /* scanner's input file descriptor */

/*
 *      _nc_reset_input()
 *
 *      Resets the input-reading routines.  Used on initialization,
 *      or after a seek has been done.  Exactly one argument must be
 *      non-null.
 */

NCURSES_EXPORT(void)
_nc_reset_input(FILE *fp, char *buf)
{
    TR(TRACE_DATABASE,
       (T_CALLED("_nc_reset_input(fp=%p, buf=%p)"), (void *) fp, buf));

    pushtype = NO_PUSHBACK;
    if (pushname != 0)
        pushname[0] = '\0';
    yyin = fp;
    bufstart = bufptr = buf;
    _nc_curr_file_pos = 0L;
    if (fp != 0)
        _nc_curr_line = 0;
    _nc_curr_col = 0;

    returnVoidDB;
}

/*
 *      int last_char()
 *
 *      Returns the final nonblank character on the current input buffer
 */
static int
last_char(int from_end)
{
    size_t len = strlen(bufptr);
    int result = 0;

    while (len--) {
        if (!isspace(UChar(bufptr[len]))) {
            if (from_end <= (int) len)
                result = bufptr[(int) len - from_end];
            break;
        }
    }
    return result;
}

/*
 * Read, like fgets(), but error-out if the input contains nulls.
 */
static int
get_text(char *buffer, int length)
{
    int count = 0;
    int limit = length - 1;

    while (limit-- > 0) {
        int ch = fgetc(yyin);

        if (ch == '\0') {
            _nc_err_abort("This is not a text-file");
        } else if (ch == EOF) {
            break;
        }
        ++count;
        *buffer++ = (char) ch;
        if (ch == '\n')
            break;
    }
    *buffer = '\0';
    return count;
}

/*
 *      int next_char()
 *
 *      Returns the next character in the input stream.  Comments and leading
 *      white space are stripped.
 *
 *      The global state variable 'firstcolumn' is set TRUE if the character
 *      returned is from the first column of the input line.
 *
 *      The global variable _nc_curr_line is incremented for each new line.
 *      The global variable _nc_curr_file_pos is set to the file offset of the
 *      beginning of each line.
 */

static int
next_char(void)
{
    static char *result;
    static size_t allocated;
    int the_char;

    if (!yyin) {
        if (result != 0) {
            FreeAndNull(result);
            FreeAndNull(pushname);
            bufptr = 0;
            bufstart = 0;
            allocated = 0;
        }
        /*
         * An string with an embedded null will truncate the input.  This is
         * intentional (we don't read binary files here).
         */
        if (bufptr == 0 || *bufptr == '\0')
            return (EOF);
        if (*bufptr == '\n') {
            _nc_curr_line++;
            _nc_curr_col = 0;
        } else if (*bufptr == '\t') {
            _nc_curr_col = (_nc_curr_col | 7);
        }
    } else if (!bufptr || !*bufptr) {
        /*
         * In theory this could be recoded to do its I/O one character at a
         * time, saving the buffer space.  In practice, this turns out to be
         * quite hard to get completely right.  Try it and see.  If you
         * succeed, don't forget to hack push_back() correspondingly.
         */
        size_t len;

        do {
            size_t used = 0;
            bufstart = 0;
            do {
                if (used + (LEXBUFSIZ / 4) >= allocated) {
                    allocated += (allocated + LEXBUFSIZ);
                    result = typeRealloc(char, allocated, result);
                    if (result == 0)
                        return (EOF);
                    if (bufstart)
                        bufstart = result;
                }
                if (used == 0)
                    _nc_curr_file_pos = ftell(yyin);

                if (get_text(result + used, (int) (allocated - used))) {
                    bufstart = result;
                    if (used == 0) {
                        if (_nc_curr_line == 0
                            && IS_TIC_MAGIC(result)) {
                            _nc_err_abort("This is a compiled terminal description, not a source");
                        }
                        _nc_curr_line++;
                        _nc_curr_col = 0;
                    }
                } else {
                    if (used != 0)
                        _nc_STRCAT(result, "\n", allocated);
                }
                if ((bufptr = bufstart) != 0) {
                    used = strlen(bufptr);
                    if (used == 0)
                        return (EOF);
                    while (iswhite(*bufptr)) {
                        if (*bufptr == '\t') {
                            _nc_curr_col = (_nc_curr_col | 7) + 1;
                        } else {
                            _nc_curr_col++;
                        }
                        bufptr++;
                    }

                    /*
                     * Treat a trailing <cr><lf> the same as a <newline> so we
                     * can read files on OS/2, etc.
                     */
                    if ((len = strlen(bufptr)) > 1) {
                        if (bufptr[len - 1] == '\n'
                            && bufptr[len - 2] == '\r') {
                            len--;
                            bufptr[len - 1] = '\n';
                            bufptr[len] = '\0';
                        }
                    }
                } else {
                    return (EOF);
                }
            } while (bufptr[len - 1] != '\n');  /* complete a line */
        } while (result[0] == '#');     /* ignore comments */
    } else if (*bufptr == '\t') {
        _nc_curr_col = (_nc_curr_col | 7);
    }

    first_column = (bufptr == bufstart);
    if (first_column)
        had_newline = FALSE;

    _nc_curr_col++;
    the_char = *bufptr++;
    return UChar(the_char);
}

static void
push_back(int c)
/* push a character back onto the input stream */
{
    if (bufptr == bufstart)
        _nc_syserr_abort("cannot backspace off beginning of line");
    *--bufptr = (char) c;
    _nc_curr_col--;
}

static long
stream_pos(void)
/* return our current character position in the input stream */
{
    return (yyin ? ftell(yyin) : (bufptr ? (long) (bufptr - bufstart) : 0));
}

static bool
end_of_stream(void)
/* are we at end of input? */
{
    return ((yyin
             ? (feof(yyin) && (bufptr == NULL || *bufptr == '\0'))
             : (bufptr && *bufptr == '\0'))
            ? TRUE : FALSE);
}

/* Assume we may be looking at a termcap-style continuation */
static NCURSES_INLINE int
eat_escaped_newline(int ch)
{
    if (ch == '\\') {
        while ((ch = next_char()) == '\n' || iswhite(ch)) {
            /* EMPTY */ ;
        }
    }
    return ch;
}

#define TOK_BUF_SIZE MAX_ENTRY_SIZE

#define OkToAdd() \
        ((tok_ptr - tok_buf) < (TOK_BUF_SIZE - 2))

#define AddCh(ch) \
        *tok_ptr++ = (char) ch; \
        *tok_ptr = '\0'

static char *tok_buf;

/*
 *      int
 *      get_token()
 *
 *      Scans the input for the next token, storing the specifics in the
 *      global structure 'curr_token' and returning one of the following:
 *
 *              NAMES           A line beginning in column 1.  'name'
 *                              will be set to point to everything up to but
 *                              not including the first separator on the line.
 *              BOOLEAN         An entry consisting of a name followed by
 *                              a separator.  'name' will be set to point to
 *                              the name of the capability.
 *              NUMBER          An entry of the form
 *                                      name#digits,
 *                              'name' will be set to point to the capability
 *                              name and 'valnumber' to the number given.
 *              STRING          An entry of the form
 *                                      name=characters,
 *                              'name' is set to the capability name and
 *                              'valstring' to the string of characters, with
 *                              input translations done.
 *              CANCEL          An entry of the form
 *                                      name@,
 *                              'name' is set to the capability name and
 *                              'valnumber' to -1.
 *              EOF             The end of the file has been reached.
 *
 *      A `separator' is either a comma or a semicolon, depending on whether
 *      we are in termcap or terminfo mode.
 *
 */

NCURSES_EXPORT(int)
_nc_get_token(bool silent)
{
    static const char terminfo_punct[] = "@%&*!#";

    char *after_name;           /* after primary name */
    char *after_list;           /* after primary and alias list */
    char *numchk;
    char *tok_ptr;
    char *s;
    char numbuf[80];
    int ch, c0, c1;
    int dot_flag = FALSE;
    int type;
    long number;
    long token_start;
    unsigned found;
#ifdef TRACE
    int old_line;
    int old_col;
#endif

    DEBUG(3, (T_CALLED("_nc_get_token(silent=%d)"), silent));

    if (pushtype != NO_PUSHBACK) {
        int retval = pushtype;

        _nc_set_type(pushname != 0 ? pushname : "");
        DEBUG(3, ("pushed-back token: `%s', class %d",
                  _nc_curr_token.tk_name, pushtype));

        pushtype = NO_PUSHBACK;
        if (pushname != 0)
            pushname[0] = '\0';

        /* currtok wasn't altered by _nc_push_token() */
        DEBUG(3, (T_RETURN("%d"), retval));
        return (retval);
    }

    if (end_of_stream()) {
        yyin = 0;
        (void) next_char();     /* frees its allocated memory */
        if (tok_buf != 0) {
            if (_nc_curr_token.tk_name == tok_buf)
                _nc_curr_token.tk_name = 0;
        }
        DEBUG(3, (T_RETURN("%d"), EOF));
        return (EOF);
    }

  start_token:
    token_start = stream_pos();
    while ((ch = next_char()) == '\n' || iswhite(ch)) {
        if (ch == '\n')
            had_newline = TRUE;
    }

    ch = eat_escaped_newline(ch);
    _nc_curr_token.tk_valstring = 0;

#ifdef TRACE
    old_line = _nc_curr_line;
    old_col = _nc_curr_col;
#endif
    if (ch == EOF)
        type = EOF;
    else {
        /* if this is a termcap entry, skip a leading separator */
        if (separator == ':' && ch == ':')
            ch = next_char();

        if (ch == '.'
#if NCURSES_EXT_FUNCS
            && !_nc_disable_period
#endif
            ) {
            dot_flag = TRUE;
            DEBUG(8, ("dot-flag set"));

            while ((ch = next_char()) == '.' || iswhite(ch)) {
                /* EMPTY */ ;
            }
        }

        if (ch == EOF) {
            type = EOF;
            goto end_of_token;
        }

        /* have to make some punctuation chars legal for terminfo */
        if (!isalnum(UChar(ch))
#if NCURSES_EXT_FUNCS
            && !(ch == '.' && _nc_disable_period)
#endif
            && ((strchr) (terminfo_punct, (char) ch) == 0)) {
            if (!silent)
                _nc_warning("Illegal character (expected alphanumeric or %s) - '%s'",
                            terminfo_punct, unctrl(UChar(ch)));
            _nc_panic_mode(separator);
            goto start_token;
        }

        if (tok_buf == 0)
            tok_buf = typeMalloc(char, TOK_BUF_SIZE);

#ifdef TRACE
        old_line = _nc_curr_line;
        old_col = _nc_curr_col;
#endif
        tok_ptr = tok_buf;
        AddCh(ch);

        if (first_column) {
            _nc_comment_start = token_start;
            _nc_comment_end = _nc_curr_file_pos;
            _nc_start_line = _nc_curr_line;

            _nc_syntax = ERR;
            after_name = 0;
            after_list = 0;
            while ((ch = next_char()) != '\n') {
                if (ch == EOF) {
                    _nc_err_abort(MSG_NO_INPUTS);
                } else if (ch == '|') {
                    after_list = tok_ptr;
                    if (after_name == 0)
                        after_name = tok_ptr;
                } else if (ch == ':' && last_char(0) != ',') {
                    _nc_syntax = SYN_TERMCAP;
                    separator = ':';
                    break;
                } else if (ch == ',') {
                    _nc_syntax = SYN_TERMINFO;
                    separator = ',';
                    /*
                     * If we did not see a '|', then we found a name with no
                     * aliases or description.
                     */
                    if (after_name == 0)
                        break;
                    /*
                     * We saw a comma, but are not entirely sure this is
                     * terminfo format, since we can still be parsing the
                     * description field (for either syntax).
                     *
                     * A properly formatted termcap line ends with either a
                     * colon, or a backslash after a colon.  It is possible
                     * to have a backslash in the middle of a capability, but
                     * then there would be no leading whitespace on the next
                     * line - something we want to discourage.
                     */
                    c0 = last_char(0);
                    c1 = last_char(1);
                    if (c1 != ':' && c0 != '\\' && c0 != ':') {
                        bool capability = FALSE;

                        /*
                         * Since it is not termcap, assume the line is terminfo
                         * format.  However, the comma can be embedded in a
                         * description field.  It also can be a separator
                         * between a description field and a capability.
                         *
                         * Improve the guess by checking if the next word after
                         * the comma does not look like a capability.  In that
                         * case, extend the description past the comma.
                         */
                        for (s = bufptr; isspace(UChar(*s)); ++s) {
                            ;
                        }
                        if (islower(UChar(*s))) {
                            char *name = s;
                            while (isalnum(UChar(*s))) {
                                ++s;
                            }
                            if (*s == '#' || *s == '=' || *s == '@') {
                                /*
                                 * Checking solely with syntax allows us to
                                 * support extended capabilities with string
                                 * values.
                                 */
                                capability = TRUE;
                            } else if (*s == ',') {
                                c0 = *s;
                                *s = '\0';
                                /*
                                 * Otherwise, we can handle predefined boolean
                                 * capabilities, still aided by syntax.
                                 */
                                if (_nc_find_entry(name,
                                                   _nc_get_hash_table(FALSE))) {
                                    capability = TRUE;
                                }
                                *s = (char) c0;
                            }
                        }
                        if (capability) {
                            break;
                        }
                    }
                } else
                    ch = eat_escaped_newline(ch);

                if (OkToAdd()) {
                    AddCh(ch);
                } else {
                    break;
                }
            }
            *tok_ptr = '\0';
            if (_nc_syntax == ERR) {
                /*
                 * Grrr...what we ought to do here is barf, complaining that
                 * the entry is malformed.  But because a couple of name fields
                 * in the 8.2 termcap file end with |\, we just have to assume
                 * it is termcap syntax.
                 */
                _nc_syntax = SYN_TERMCAP;
                separator = ':';
            } else if (_nc_syntax == SYN_TERMINFO) {
                /* throw away trailing /, *$/ */
                for (--tok_ptr;
                     iswhite(*tok_ptr) || *tok_ptr == ',';
                     tok_ptr--) {
                    /* EMPTY */ ;
                }
                tok_ptr[1] = '\0';
            }

            /*
             * This is the soonest we have the terminal name fetched.  Set up
             * for following warning messages.  If there's no '|', then there
             * is no description.
             */
            if (after_name != 0) {
                ch = *after_name;
                *after_name = '\0';
                _nc_set_type(tok_buf);
                *after_name = (char) ch;
            }

            /*
             * Compute the boundary between the aliases and the description
             * field for syntax-checking purposes.
             */
            if (after_list != 0) {
                if (!silent) {
                    if (*after_list == '\0' || strchr("|", after_list[1]) != NULL) {
                        _nc_warning("empty longname field");
                    } else if (strchr(after_list, ' ') == 0) {
                        _nc_warning("older tic versions may treat the description field as an alias");
                    }
                }
            } else {
                after_list = tok_buf + strlen(tok_buf);
                DEBUG(2, ("missing description"));
            }

            /*
             * Whitespace in a name field other than the long name can confuse
             * rdist and some termcap tools.  Slashes are a no-no.  Other
             * special characters can be dangerous due to shell expansion.
             */
            for (s = tok_buf; s < after_list; ++s) {
                if (isspace(UChar(*s))) {
                    if (!silent)
                        _nc_warning("whitespace in name or alias field");
                    break;
                } else if (*s == '/') {
                    if (!silent)
                        _nc_warning("slashes aren't allowed in names or aliases");
                    break;
                } else if (strchr("$[]!*?", *s)) {
                    if (!silent)
                        _nc_warning("dubious character `%c' in name or alias field", *s);
                    break;
                }
            }

            _nc_curr_token.tk_name = tok_buf;
            type = NAMES;
        } else {
            if (had_newline && _nc_syntax == SYN_TERMCAP) {
                _nc_warning("Missing backslash before newline");
                had_newline = FALSE;
            }
            while ((ch = next_char()) != EOF) {
                if (!isalnum(UChar(ch))) {
                    if (_nc_syntax == SYN_TERMINFO) {
                        if (ch != '_')
                            break;
                    } else {    /* allow ';' for "k;" */
                        if (ch != ';')
                            break;
                    }
                }
                if (OkToAdd()) {
                    AddCh(ch);
                } else {
                    ch = EOF;
                    break;
                }
            }

            *tok_ptr++ = '\0';  /* separate name/value in buffer */
            switch (ch) {
            case ',':
            case ':':
                if (ch != separator)
                    _nc_err_abort("Separator inconsistent with syntax");
                _nc_curr_token.tk_name = tok_buf;
                type = BOOLEAN;
                break;
            case '@':
                if ((ch = next_char()) != separator && !silent)
                    _nc_warning("Missing separator after `%s', have %s",
                                tok_buf, unctrl(UChar(ch)));
                _nc_curr_token.tk_name = tok_buf;
                type = CANCEL;
                break;

            case '#':
                found = 0;
                while (isalnum(ch = next_char())) {
                    numbuf[found++] = (char) ch;
                    if (found >= sizeof(numbuf) - 1)
                        break;
                }
                numbuf[found] = '\0';
                number = strtol(numbuf, &numchk, 0);
                if (!silent) {
                    if (numchk == numbuf)
                        _nc_warning("no value given for `%s'", tok_buf);
                    if ((*numchk != '\0') || (ch != separator))
                        _nc_warning("Missing separator for `%s'", tok_buf);
                    if (number < 0)
                        _nc_warning("value of `%s' cannot be negative", tok_buf);
                    if (number > MAX_OF_TYPE(NCURSES_INT2)) {
                        _nc_warning("limiting value of `%s' from %#lx to %#x",
                                    tok_buf,
                                    number, MAX_OF_TYPE(NCURSES_INT2));
                        number = MAX_OF_TYPE(NCURSES_INT2);
                    }
                }
                _nc_curr_token.tk_name = tok_buf;
                _nc_curr_token.tk_valnumber = (int) number;
                type = NUMBER;
                break;

            case '=':
                ch = _nc_trans_string(tok_ptr, tok_buf + TOK_BUF_SIZE);
                if (!silent && ch != separator)
                    _nc_warning("Missing separator");
                _nc_curr_token.tk_name = tok_buf;
                _nc_curr_token.tk_valstring = tok_ptr;
                type = STRING;
                break;

            case EOF:
                type = EOF;
                break;
            default:
                /* just to get rid of the compiler warning */
                type = UNDEF;
                if (!silent)
                    _nc_warning("Illegal character - '%s'", unctrl(UChar(ch)));
            }
        }                       /* end else (first_column == FALSE) */
    }                           /* end else (ch != EOF) */

  end_of_token:

#ifdef TRACE
    if (dot_flag == TRUE)
        DEBUG(8, ("Commented out "));

    if (_nc_tracing >= DEBUG_LEVEL(8)) {
        _tracef("parsed %d.%d to %d.%d",
                old_line, old_col,
                _nc_curr_line, _nc_curr_col);
    }
    if (_nc_tracing >= DEBUG_LEVEL(7)) {
        switch (type) {
        case BOOLEAN:
            _tracef("Token: Boolean; name='%s'",
                    _nc_curr_token.tk_name);
            break;

        case NUMBER:
            _tracef("Token: Number;  name='%s', value=%d",
                    _nc_curr_token.tk_name,
                    _nc_curr_token.tk_valnumber);
            break;

        case STRING:
            _tracef("Token: String;  name='%s', value=%s",
                    _nc_curr_token.tk_name,
                    _nc_visbuf(_nc_curr_token.tk_valstring));
            break;

        case CANCEL:
            _tracef("Token: Cancel; name='%s'",
                    _nc_curr_token.tk_name);
            break;

        case NAMES:

            _tracef("Token: Names; value='%s'",
                    _nc_curr_token.tk_name);
            break;

        case EOF:
            _tracef("Token: End of file");
            break;

        default:
            _nc_warning("Bad token type");
        }
    }
#endif

    if (dot_flag == TRUE)       /* if commented out, use the next one */
        type = _nc_get_token(silent);

    DEBUG(3, ("token: `%s', class %d",
              ((_nc_curr_token.tk_name != 0)
               ? _nc_curr_token.tk_name
               : "<null>"),
              type));

    DEBUG(3, (T_RETURN("%d"), type));
    return (type);
}

/*
 *      char
 *      trans_string(ptr)
 *
 *      Reads characters using next_char() until encountering a separator, nl,
 *      or end-of-file.  The returned value is the character which caused
 *      reading to stop.  The following translations are done on the input:
 *
 *              ^X  goes to  ctrl-X (i.e. X & 037)
 *              {\E,\n,\r,\b,\t,\f}  go to
 *                      {ESCAPE,newline,carriage-return,backspace,tab,formfeed}
 *              {\^,\\}  go to  {carat,backslash}
 *              \ddd (for ddd = up to three octal digits)  goes to the character ddd
 *
 *              \e == \E
 *              \0 == \200
 *
 */

NCURSES_EXPORT(int)
_nc_trans_string(char *ptr, const char *const last)
{
    int count = 0;
    int number = 0;
    int i, c;
    int last_ch = '\0';
    bool ignored = FALSE;
    bool long_warning = FALSE;

    while ((c = next_char()) != separator && c != EOF) {
        if (ptr >= (last - 1)) {
            if (c != EOF) {
                while ((c = next_char()) != separator && c != EOF) {
                    ;
                }
            }
            break;
        }
        if ((_nc_syntax == SYN_TERMCAP) && c == '\n')
            break;
        if (c == '^' && last_ch != '%') {
            c = next_char();
            if (c == EOF)
                _nc_err_abort(MSG_NO_INPUTS);

            if (!(is7bits(c) && isprint(c))) {
                _nc_warning("Illegal ^ character - '%s'", unctrl(UChar(c)));
            }
            if (c == '?' && (_nc_syntax != SYN_TERMCAP)) {
                *(ptr++) = '\177';
            } else {
                if ((c &= 037) == 0)
                    c = 128;
                *(ptr++) = (char) (c);
            }
        } else if (c == '\\') {
            bool strict_bsd = ((_nc_syntax == SYN_TERMCAP) && _nc_strict_bsd);

            c = next_char();
            if (c == EOF)
                _nc_err_abort(MSG_NO_INPUTS);

            if (isoctal(c) || (strict_bsd && isdigit(c))) {
                number = c - '0';
                for (i = 0; i < 2; i++) {
                    c = next_char();
                    if (c == EOF)
                        _nc_err_abort(MSG_NO_INPUTS);

                    if (!isoctal(c)) {
                        if (isdigit(c)) {
                            if (!strict_bsd) {
                                _nc_warning("Non-octal digit `%c' in \\ sequence", c);
                                /* allow the digit; it'll do less harm */
                            }
                        } else {
                            push_back(c);
                            break;
                        }
                    }

                    number = number * 8 + c - '0';
                }

                number = UChar(number);
                if (number == 0 && !strict_bsd)
                    number = 0200;
                *(ptr++) = (char) number;
            } else {
                switch (c) {
                case 'E':
                    *(ptr++) = '\033';
                    break;

                case 'n':
                    *(ptr++) = '\n';
                    break;

                case 'r':
                    *(ptr++) = '\r';
                    break;

                case 'b':
                    *(ptr++) = '\010';
                    break;

                case 'f':
                    *(ptr++) = '\014';
                    break;

                case 't':
                    *(ptr++) = '\t';
                    break;

                case '\\':
                    *(ptr++) = '\\';
                    break;

                case '^':
                    *(ptr++) = '^';
                    break;

                case ',':
                    *(ptr++) = ',';
                    break;

                case '\n':
                    continue;

                default:
                    if ((_nc_syntax == SYN_TERMINFO) || !_nc_strict_bsd) {
                        switch (c) {
                        case 'a':
                            c = '\007';
                            break;
                        case 'e':
                            c = '\033';
                            break;
                        case 'l':
                            c = '\n';
                            break;
                        case 's':
                            c = ' ';
                            break;
                        case ':':
                            c = ':';
                            break;
                        default:
                            _nc_warning("Illegal character '%s' in \\ sequence",
                                        unctrl(UChar(c)));
                            break;
                        }
                    }
                    /* FALLTHRU */
                case '|':
                    *(ptr++) = (char) c;
                }               /* endswitch (c) */
            }                   /* endelse (c < '0' ||  c > '7') */
        }
        /* end else if (c == '\\') */
        else if (c == '\n' && (_nc_syntax == SYN_TERMINFO)) {
            /*
             * Newlines embedded in a terminfo string are ignored, provided
             * that the next line begins with whitespace.
             */
            ignored = TRUE;
        } else {
            *(ptr++) = (char) c;
        }

        if (!ignored) {
            if (_nc_curr_col <= 1) {
                push_back(c);
                c = '\n';
                break;
            }
            last_ch = c;
            count++;
        }
        ignored = FALSE;

        if (count > MAXCAPLEN && !long_warning) {
            _nc_warning("Very long string found.  Missing separator?");
            long_warning = TRUE;
        }
    }                           /* end while */

    *ptr = '\0';

    return (c);
}

/*
 *      _nc_push_token()
 *
 *      Push a token of given type so that it will be reread by the next
 *      get_token() call.
 */

NCURSES_EXPORT(void)
_nc_push_token(int tokclass)
{
    /*
     * This implementation is kind of bogus, it will fail if we ever do more
     * than one pushback at a time between get_token() calls.  It relies on the
     * fact that _nc_curr_token is static storage that nothing but
     * _nc_get_token() touches.
     */
    pushtype = tokclass;
    if (pushname == 0)
        pushname = typeMalloc(char, MAX_NAME_SIZE + 1);
    _nc_get_type(pushname);

    DEBUG(3, ("pushing token: `%s', class %d",
              ((_nc_curr_token.tk_name != 0)
               ? _nc_curr_token.tk_name
               : "<null>"),
              pushtype));
}

/*
 * Panic mode error recovery - skip everything until a "ch" is found.
 */
NCURSES_EXPORT(void)
_nc_panic_mode(char ch)
{
    for (;;) {
        int c = next_char();
        if (c == ch)
            return;
        if (c == EOF)
            return;
    }
}

#if NO_LEAKS
NCURSES_EXPORT(void)
_nc_comp_scan_leaks(void)
{
    if (pushname != 0) {
        FreeAndNull(pushname);
    }
    if (tok_buf != 0) {
        FreeAndNull(tok_buf);
    }
}
#endif