compressFile

From R.utils v2.0.0 by Henrik Bengtsson

Compressing and decompressing files

Compressing and decompressing files such as gzip:ed and bzip2:ed files.

Keywords: file, programming

Usage

## S3 method for class 'default':
compressFile(filename, destname=sprintf("\%s.\%s", filename, ext), ext, FUN,
  temporary=FALSE, skip=FALSE, overwrite=FALSE, remove=TRUE, BFR.SIZE=1e+07, ...)
 ## S3 method for class 'default':
decompressFile(filename, destname=gsub(sprintf("[.]\%s$", ext), "", filename,
  ignore.case = TRUE), ext, FUN, temporary=FALSE, skip=FALSE, overwrite=FALSE,
  remove=TRUE, BFR.SIZE=1e+07, ...)
 ## S3 method for class 'default':
isCompressedFile(filename, method=c("extension", "content"), ext, fileClass, ...)
 ## S3 method for class 'default':
bzip2(filename, ..., ext="bz2", FUN=bzfile)
 ## S3 method for class 'default':
bunzip2(filename, ..., ext="bz2", FUN=bzfile)
 ## S3 method for class 'default':
gzip(filename, ..., ext="gz", FUN=gzfile)
 ## S3 method for class 'default':
gunzip(filename, ..., ext="gz", FUN=gzfile)

Arguments

filename: Pathname of input file.
destname: Pathname of output file.
temporary: If TRUE, the output file is created in a temporary directory.
skip: If TRUE and the output file already exists, the output file is returned as is.
overwrite: If TRUE and the output file already exists, the file is silently overwritting, otherwise an exception is thrown (unless skip is TRU
remove: If TRUE, the input file is removed afterward, otherwise not.
BFR.SIZE: The number of bytes read in each chunk.
...: Passed to the underlying function or alternatively not used.
method: A character string specifying how to infer whether a file is compressed or not.
ext, fileClass, FUN: (internal) Filename extension, file class, and a connection function used to read from/write to file.

Details

Internally bzfile() and gzfile() (see connections) are used to read (write) files. If the process is interrupted before completed, the partially written output file is automatically removed.

Value

Returns the pathname of the output file. The number of bytes processed is returned as an attribute.
isCompressedFile() etc. return a logical.

Examples

## bzip2
  cat(file="foo.txt", "Hello world!")
  print(isBzipped("foo.txt"))
  print(isBzipped("foo.txt.bz2"))

  bzip2("foo.txt")
  print(file.info("foo.txt.bz2"))
  print(isBzipped("foo.txt"))
  print(isBzipped("foo.txt.bz2"))

  bunzip2("foo.txt.bz2")
  print(file.info("foo.txt"))

  ## gzip
  cat(file="foo.txt", "Hello world!")
  print(isGzipped("foo.txt"))
  print(isGzipped("foo.txt.gz"))

  gzip("foo.txt")
  print(file.info("foo.txt.gz"))
  print(isGzipped("foo.txt"))
  print(isGzipped("foo.txt.gz"))

  gunzip("foo.txt.gz")
  print(file.info("foo.txt"))

  ## Cleanup
  file.remove("foo.txt")

Documentation reproduced from package R.utils, version 2.0.0, License: LGPL (>= 2.1)

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