xxd

This is a build2 package for the Vim xxd executable. It creates a hexdump of a given file or standard input. It can also convert a hexdump back to its original binary form. One notable xxd mode is -i|--include, which generates a C array definition of the input that can be used to embed binary data into C/C++ programs. This functionality is the primary reason for the use of this package.

Note that the xxd executable in this page provides build2 metadata.

Usage

To start using xxd in your project, add the following build-time depends value to your manifest, adjusting the version constraint as appropriate:

depends: * xxd >= 8.2.3075

Then import the executable in your buildfile:

import! [metadata] xxd = xxd%exe{xxd}

While the default output of the -i|--include mode is a bit old school (using unsigned int instead of size_t) and the array/length names are derived from the input file name (including directories), xxd can also produce just the array values allowing us to wrap it into an array of our choice. Below are some examples of build2 ad hoc recipes:

# Use the default output. Array and length names will be binary_bin and
# binary_bin_len.
#
cxx{binary}: file{binary.bin} $xxd
{{
  i = $path($<[0])
  env --cwd $directory($i) -- $xxd -i $leaf($i) >$path($>)
}}

# Use just the file name without the extension for names and size_t for
# length.
#
cxx{binary}: file{binary.bin} $xxd
{{
  i = $path($<[0]) # Input.
  o = $path($>)    # Output.
  n = $name($<[0]) # Array name.

  echo "#include <cstddef>"                     >$o
  echo "unsigned char $n[] = {"                >>$o
  $xxd -i <$i                                  >>$o
  echo "};"                                    >>$o
  echo "std::size_t $(n)_len = sizeof \($n\);" >>$o
}}

# Generate both the header with declarations and the source file with
# definitions.
#
<{hxx cxx}{binary}>: file{binary.bin} $xxd
{{
  i = $path($<[0]) # Input.
  h = $path($>[0]) # Output header.
  s = $path($>[1]) # Output source.
  n = $name($<[0]) # Array name.

  # Get the position of the last byte (in hex).
  #
  $xxd -s -1 -l 1 $i | sed -n -e 's/^([0-9a-f]+):.*$/\1/p' - | set pos

  if ($empty($pos))
    exit "unable to extract input size from xxd output"
  end

  # Write the header and source.
  #
  echo "#pragma once"                          >$h
  echo "extern unsigned char $n[0x$pos + 1];" >>$h

  echo "unsigned char $n[0x$pos + 1] = {"      >$s
  $xxd -i <$i                                 >>$s
  echo '};'                                   >>$s
}}