R/utility.R

In LaF: Fast Access to Large ASCII Files

# Copyright 2012 Jan van der Laan
#
# This file is part of LaF.
#
# LaF is free software: you can redistribute it and/or modify it under the terms
# of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# LaF is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# LaF.  If not, see <http://www.gnu.org/licenses/>.

# =============================================================================
# Check if a file can be opened for reading. This function is more robust than
# using file.access.
.file_readable <- function(filename) {
    tryCatch({
            con <- file(filename, "r")
            close(con)
            return(TRUE)
        }, error = function(e) {}, warning = function(w) {})
    return(FALSE)
}