expand.c

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        return 0;
      };
      break;
    };
/*
 * After passing the first character, turn off the explicit match
 * requirement.
 */
    xplicit = 0;
  };
/*
 * To get here the pattern must have been exhausted. If the filename
 * string matched, then the filename string must also have been
 * exhausted.
 */
  return *fptr == '\0';
}

/*.......................................................................
 * Match a character range expression terminated by an unescaped close
 * square bracket.
 *
 * Input:
 *  c               int     The character to be matched with the range
 *                          pattern.
 *  pattern  const char *   The range pattern to be matched (ie. after the
 *                          initiating '[' character).
 *  endp     const char **  On output a pointer to the character following the
 *                          range expression will be assigned to *endp.
 * Output:
 *  return          int     0 - Doesn't match.
 *                          1 - The character matched.
 */
static int ef_matches_range(int c, const char *pattern, const char **endp)
{
  const char *pptr = pattern;  /* The pointer used to scan the pattern */
  int invert = 0;              /* True to invert the sense of the match */
  int matched = 0;             /* True if the character matched the pattern */
/*
 * If the first character is a caret, the sense of the match is
 * inverted and only if the character isn't one of those in the
 * range, do we say that it matches.
 */
  if(*pptr == '^') {
    pptr++;
    invert = 1;
  };
/*
 * The hyphen is only a special character when it follows the first
 * character of the range (not including the caret).
 */
  if(*pptr == '-') {
    pptr++;
    if(c == '-') {
      *endp = pptr;
      matched = 1;
    };
/*
 * Skip other leading '-' characters since they make no sense.
 */
    while(*pptr == '-')
      pptr++;
  };
/*
 * The hyphen is only a special character when it follows the first
 * character of the range (not including the caret or a hyphen).
 */
  if(*pptr == ']') {
    pptr++;
    if(c == ']') {
      *endp = pptr;
      matched = 1;
    };
  };
/*
 * Having dealt with the characters that have special meanings at
 * the beginning of a character range expression, see if the
 * character matches any of the remaining characters of the range,
 * up until a terminating ']' character is seen.
 */
  while(!matched && *pptr && *pptr != ']') {
/*
 * Is this a range of characters signaled by the two end characters
 * separated by a hyphen?
 */
    if(*pptr == '-') {
      if(pptr[1] != ']') {
        if(c >= pptr[-1] && c <= pptr[1])
	  matched = 1;
	pptr += 2;
      };
/*
 * A normal character to be compared directly.
 */
    } else if(*pptr++ == c) {
      matched = 1;
    };
  };
/*
 * Find the terminating ']'.
 */
  while(*pptr && *pptr != ']')
    pptr++;
/*
 * Did we find a terminating ']'?
 */
  if(*pptr == ']') {
    *endp = pptr + 1;
    return matched ? !invert : invert;
  };
/*
 * If the pattern didn't end with a ']' then it doesn't match, regardless
 * of the value of the required sense of the match.
 */
  *endp = pptr;
  return 0;
}

/*.......................................................................
 * This is a qsort() comparison function used to sort strings.
 *
 * Input:
 *  v1, v2   void *  Pointers to the two strings to be compared.
 * Output:
 *  return    int    -1 -> v1 < v2.
 *                    0 -> v1 == v2
 *                    1 -> v1 > v2
 */
static int ef_cmp_strings(const void *v1, const void *v2)
{
  char * const *s1 = (char * const *) v1;
  char * const *s2 = (char * const *) v2;
  return strcmp(*s1, *s2);
}

/*.......................................................................
 * Preprocess a path, expanding ~/, ~user/ and $envvar references, using
 * ef->path as a work buffer, then copy the result into a cache entry,
 * and return a pointer to this copy.
 *
 * Input:
 *  ef    ExpandFile *  The resource object of the file matcher.
 *  pathlen      int    The length of the prefix of path[] to be expanded.
 * Output:
 *  return      char *  A pointer to a copy of the output path in the
 *                      cache. On error NULL is returned, and a description
 *                      of the error is left in ef->errmsg[].
 */
static char *ef_expand_special(ExpandFile *ef, const char *path, int pathlen)
{
  int spos;      /* The index of the start of the path segment that needs */
                 /*  to be copied from path[] to the output pathname. */
  int ppos;      /* The index of a character in path[] */
  char *pptr;    /* A pointer into the output path */
  int escaped;   /* True if the previous character was a '\' */
  int i;
/*
 * Clear the pathname buffer.
 */
  _pn_clear_path(ef->path);
/*
 * We need to perform two passes, one to expand environment variables
 * and a second to do tilde expansion. This caters for the case
 * where an initial dollar expansion yields a tilde expression.
 */
  escaped = 0;
  for(spos=ppos=0; ppos < pathlen; ppos++) {
    int c = path[ppos];
    if(escaped) {
      escaped = 0;
    } else if(c == '\\') {
      escaped = 1;
    } else if(c == '$') {
      int envlen;   /* The length of the environment variable */
      char *value;  /* The value of the environment variable */
/*
 * Record the preceding unrecorded part of the pathname.
 */
      if(spos < ppos && _pn_append_to_path(ef->path, path + spos, ppos-spos, 0)
	 == NULL) {
	strcpy(ef->errmsg, "Insufficient memory to expand path");
	return NULL;
      };
/*
 * Skip the dollar.
 */
      ppos++;
/*
 * Copy the environment variable name that follows the dollar into
 * ef->envnam[], stopping if a directory separator or end of string
 * is seen.
 */
      for(envlen=0; envlen<ENV_LEN && ppos < pathlen &&
	  strncmp(path + ppos, FS_DIR_SEP, FS_DIR_SEP_LEN); envlen++)
	ef->envnam[envlen] = path[ppos++];
/*
 * If the username overflowed the buffer, treat it as invalid (note that
 * on most unix systems only 8 characters are allowed in a username,
 * whereas our ENV_LEN is much bigger than that.
 */
      if(envlen >= ENV_LEN) {
	strcpy(ef->errmsg, "Environment variable name too long");
	return NULL;
      };
/*
 * Terminate the environment variable name.
 */
      ef->envnam[envlen] = '\0';
/*
 * Lookup the value of the environment variable.
 */
      value = getenv(ef->envnam);
      if(!value) {
	const char *fmt = "No expansion found for: $%.*s";
	sprintf(ef->errmsg, fmt, ERRLEN - strlen(fmt), ef->envnam);
	return NULL;
      };
/*
 * Copy the value of the environment variable into the output pathname.
 */
      if(_pn_append_to_path(ef->path, value, -1, 0) == NULL) {
	strcpy(ef->errmsg, "Insufficient memory to expand path");
	return NULL;
      };
/*
 * Record the start of the uncopied tail of the input pathname.
 */
      spos = ppos;
    };
  };
/*
 * Record the uncopied tail of the pathname.
 */
  if(spos < ppos && _pn_append_to_path(ef->path, path + spos, ppos-spos, 0)
     == NULL) {
    strcpy(ef->errmsg, "Insufficient memory to expand path");
    return NULL;
  };
/*
 * If the first character of the resulting pathname is a tilde,
 * then attempt to substitute the home directory of the specified user.
 */
  pptr = ef->path->name;
  if(*pptr == '~' && path[0] != '\\') {
    int usrlen;           /* The length of the username following the tilde */
    const char *homedir;  /* The home directory of the user */
    int homelen;          /* The length of the home directory string */
    int plen;             /* The current length of the path */
    int skip=0;           /* The number of characters to skip after the ~user */
/*
 * Get the current length of the output path.
 */
    plen = strlen(ef->path->name);
/*
 * Skip the tilde.
 */
    pptr++;
/*
 * Copy the optional username that follows the tilde into ef->usrnam[].
 */
    for(usrlen=0; usrlen<USR_LEN && *pptr &&
	strncmp(pptr, FS_DIR_SEP, FS_DIR_SEP_LEN); usrlen++)
      ef->usrnam[usrlen] = *pptr++;
/*
 * If the username overflowed the buffer, treat it as invalid (note that
 * on most unix systems only 8 characters are allowed in a username,
 * whereas our USR_LEN is much bigger than that.
 */
    if(usrlen >= USR_LEN) {
      strcpy(ef->errmsg, "Username too long");
      return NULL;
    };
/*
 * Terminate the username string.
 */
    ef->usrnam[usrlen] = '\0';
/*
 * Lookup the home directory of the user.
 */
    homedir = _hd_lookup_home_dir(ef->home, ef->usrnam);
    if(!homedir) {
      strncpy(ef->errmsg, _hd_last_home_dir_error(ef->home), ERRLEN);
      ef->errmsg[ERRLEN] = '\0';
      return NULL;
    };
    homelen = strlen(homedir);
/*
 * ~user and ~ are usually followed by a directory separator to
 * separate them from the file contained in the home directory.
 * If the home directory is the root directory, then we don't want
 * to follow the home directory by a directory separator, so we must
 * erase it.
 */
    if(strcmp(homedir, FS_ROOT_DIR) == 0 &&
       strncmp(pptr, FS_DIR_SEP, FS_DIR_SEP_LEN) == 0) {
      skip = FS_DIR_SEP_LEN;
    };
/*
 * If needed, increase the size of the pathname buffer to allow it
 * to accomodate the home directory instead of the tilde expression.
 * Note that pptr may not be valid after this call.
 */
    if(_pn_resize_path(ef->path, plen - usrlen - 1 - skip + homelen)==NULL) {
      strcpy(ef->errmsg, "Insufficient memory to expand filename");
      return NULL;
    };
/*
 * Move the part of the pathname that follows the tilde expression to
 * the end of where the home directory will need to be inserted.
 */
    memmove(ef->path->name + homelen,
	    ef->path->name + 1 + usrlen + skip, plen - usrlen - 1 - skip+1);
/*
 * Write the home directory at the beginning of the string.
 */
    for(i=0; i<homelen; i++)
      ef->path->name[i] = homedir[i];
  };
/*
 * Copy the result into the cache, and return a pointer to the copy.
 */
  return ef_cache_pathname(ef, ef->path->name, 0);
}

/*.......................................................................
 * Return a description of the last path-expansion error that occurred.
 *
 * Input:
 *  ef     ExpandFile *   The path-expansion resource object.
 * Output:
 *  return       char *   The description of the last error.
 */
const char *ef_last_error(ExpandFile *ef)
{
  return ef ? ef->errmsg : "NULL ExpandFile argument";
}

/*.......................................................................
 * Print out an array of matching files.
 *
 * Input:
 *  result  FileExpansion *   The container of the sorted array of
 *                            expansions.
 *  fp               FILE *   The output stream to write to.
 *  term_width        int     The width of the terminal.
 * Output:
 *  return            int     0 - OK.
 *                            1 - Error.
 */
int ef_list_expansions(FileExpansion *result, FILE *fp, int term_width)
{
  int maxlen;    /* The length of the longest matching string */
  int width;     /* The width of a column */
  int ncol;      /* The number of columns to list */
  int nrow;      /* The number of rows needed to list all of the expansions */
  int row,col;   /* The row and column being written to */
  int i;
/*
 * Check the arguments.
 */
  if(!result || !fp) {
    fprintf(stderr, "ef_list_expansions: NULL argument(s).\n");
    return 1;
  };
/*
 * Not enough space to list anything?
 */
  if(term_width < 1)
    return 0;
/*
 * Work out the maximum length of the matching filenames.
 */
  maxlen = 0;
  for(i=0; i<result->nfile; i++) {
    int len = strlen(result->files[i]);
    if(len > maxlen)
      maxlen = len;
  };
/*
 * Nothing to list?
 */
  if(maxlen == 0)
    return 0;
/*
 * Split the available terminal width into columns of maxlen + 2 characters.
 */
  width = maxlen + 2;
  ncol = term_width / width;
/*
 * If the column width is greater than the terminal width, the matches will
 * just have to overlap onto the next line.
 */
  if(ncol < 1)
    ncol = 1;
/*
 * How many rows will be needed?
 */
  nrow = (result->nfile + ncol - 1) / ncol;
/*
 * Print the expansions out in ncol columns, sorted in row order within each
 * column.
 */
  for(row=0; row < nrow; row++) {
    for(col=0; col < ncol; col++) {
      int m = col*nrow + row;
      if(m < result->nfile) {
	const char *filename = result->files[m];
	if(fprintf(fp, "%s%-*s%s", filename,
		   (int) (ncol > 1 ? maxlen - strlen(filename):0), "",
		   col<ncol-1 ? "  " : "\r\n") < 0)
	  return 1;
      } else {
	if(fprintf(fp, "\r\n") < 0)
	  return 1;
	break;
      };
    };
  };
  return 0;
}