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comp_scan.c

/****************************************************************************
 * Copyright (c) 1998-2002,2003 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>                         *
 ****************************************************************************/

/*
 *    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 <term_entry.h>
#include <tic.h>

MODULE_ID("$Id: comp_scan.c,v 1.66 2003/12/14 00:32:40 tom 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(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

static bool end_of_stream(void);
static int last_char(void);
static int next_char(void);
static long stream_pos(void);
static void push_back(char c);

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

/*
 *    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[] = "@%&*!#";
    static char *buffer;

    char *after_list;
    char *after_name;
    char *numchk;
    char *ptr;
    char *s;
    char numbuf[80];
    int ch;
    int dot_flag = FALSE;
    int type;
    long number;
    long token_start;
    unsigned found;

    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() */
      return (retval);
    }

    if (end_of_stream()) {
      if (buffer != 0) {
          FreeAndNull(buffer);
      }
      return (EOF);
    }

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

    ch = eat_escaped_newline(ch);

    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))
            continue;
      }

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

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

      if (buffer == 0)
          buffer = typeMalloc(char, MAX_ENTRY_SIZE);

      ptr = buffer;
      *(ptr++) = 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_MEMORY);
            } else if (ch == '|') {
                after_list = ptr;
                if (after_name == 0)
                  after_name = ptr;
            } else if (ch == ':' && last_char() != ',') {
                _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;
                /*
                 * If we see a comma, we assume this is terminfo unless we
                 * subsequently run into a colon.  But we don't stop
                 * looking for a colon until hitting a newline.  This
                 * allows commas to be embedded in description fields of
                 * either syntax.
                 */
            } else
                ch = eat_escaped_newline(ch);

            *ptr++ = ch;
          }
          ptr[0] = '\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's termcap syntax.
             */
            _nc_syntax = SYN_TERMCAP;
            separator = ':';
          } else if (_nc_syntax == SYN_TERMINFO) {
            /* throw away trailing /, *$/ */
            for (--ptr; iswhite(*ptr) || *ptr == ','; ptr--)
                continue;
            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(buffer);
            *after_name = 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')
                  _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 = buffer + strlen(buffer);
            DEBUG(1, ("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 = buffer; 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 = buffer;
          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(ch)) {
                if (_nc_syntax == SYN_TERMINFO) {
                  if (ch != '_')
                      break;
                } else {      /* allow ';' for "k;" */
                  if (ch != ';')
                      break;
                }
            }
            *(ptr++) = ch;
          }

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

          case '#':
            found = 0;
            while (isalnum(ch = next_char())) {
                numbuf[found++] = 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'", buffer);
                if ((*numchk != '\0') || (ch != separator))
                  _nc_warning("Missing separator");
            }
            _nc_curr_token.tk_name = buffer;
            _nc_curr_token.tk_valnumber = number;
            type = NUMBER;
            break;

          case '=':
            ch = _nc_trans_string(ptr, buffer + MAX_ENTRY_SIZE);
            if (!silent && ch != separator)
                _nc_warning("Missing separator");
            _nc_curr_token.tk_name = buffer;
            _nc_curr_token.tk_valstring = 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((chtype) 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(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));

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

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

          if (!(is7bits(ch) && isprint(ch))) {
            _nc_warning("Illegal ^ character - %s", unctrl(ch));
          }
          if (ch == '?') {
            *(ptr++) = '\177';
            if (_nc_tracing)
                _nc_warning("Allow ^? as synonym for \\177");
          } else {
            if ((ch &= 037) == 0)
                ch = 128;
            *(ptr++) = (char) (ch);
          }
      } else if (ch == '\\') {
          ch = c = next_char();
          if (c == EOF)
            _nc_err_abort(MSG_NO_INPUTS);

          if (ch >= '0' && ch <= '7') {
            number = ch - '0';
            for (i = 0; i < 2; i++) {
                ch = c = next_char();
                if (c == EOF)
                  _nc_err_abort(MSG_NO_INPUTS);

                if (c < '0' || c > '7') {
                  if (isdigit(c)) {
                      _nc_warning("Non-octal digit `%c' in \\ sequence", c);
                      /* allow the digit; it'll do less harm */
                  } else {
                      push_back((char) c);
                      break;
                  }
                }

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

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

            case 'a':
                *(ptr++) = '\007';
                break;

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

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

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

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

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

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

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

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

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

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

            case '\n':
                continue;

            default:
                _nc_warning("Illegal character %s in \\ sequence",
                        unctrl(ch));
                /* FALLTHRU */
            case '|':
                *(ptr++) = (char) ch;
            }           /* endswitch (ch) */
          }             /* endelse (ch < '0' ||  ch > '7') */
      }
      /* end else if (ch == '\\') */
      else if (ch == '\n' && (_nc_syntax == SYN_TERMINFO)) {
          /* newlines embedded in a terminfo string are ignored */
          ignored = TRUE;
      } else {
          *(ptr++) = (char) ch;
      }

      if (!ignored) {
          last_ch = ch;
          count++;
      }
      ignored = FALSE;

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

    *ptr = '\0';

    return (ch);
}

/*
 *    _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, pushtype));
}

/*
 * Panic mode error recovery - skip everything until a "ch" is found.
 */
NCURSES_EXPORT(void)
_nc_panic_mode(char ch)
{
    int c;

    for (;;) {
      c = next_char();
      if (c == ch)
          return;
      if (c == EOF)
          return;
    }
}

/*****************************************************************************
 *
 * 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)
{
    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;
}

/*
 *    int last_char()
 *
 *    Returns the final nonblank character on the current input buffer
 */
static int
last_char(void)
{
    size_t len = strlen(bufptr);
    while (len--) {
      if (!isspace(UChar(bufptr[len])))
          return bufptr[len];
    }
    return 0;
}

/*
 *    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)
{
    if (!yyin) {
      /*
       * An string with an embedded null will truncate the input.  This is
       * intentional (we don't read binary files here).
       */
      if (*bufptr == '\0')
          return (EOF);
      if (*bufptr == '\n') {
          _nc_curr_line++;
          _nc_curr_col = 0;
      }
    } 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.
       */
      static char *result;
      static size_t allocated;
      size_t used;
      size_t len;

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

            if (fgets(result + used, allocated - used, yyin) != 0) {
                bufstart = result;
                if (used == 0) {
                  _nc_curr_line++;
                  _nc_curr_col = 0;
                }
            } else {
                if (used != 0)
                  strcat(result, "\n");
            }
            if ((bufptr = bufstart) != 0) {
                used = strlen(bufptr);
                while (iswhite(*bufptr))
                  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 */
    }

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

    _nc_curr_col++;
    return (*bufptr++);
}

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

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

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

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