shacolor

#!/bin/bash
set -eu

NUM=1

if [ $# -ge 1 ]; then
  case "$1" in
    -1)   NUM=1   ; shift ;;
    -2)   NUM=256 ; shift ;;
    -224) NUM=224 ; shift ;;
    -256) NUM=256 ; shift ;;
    -384) NUM=384 ; shift ;;
    -512) NUM=512 ; shift ;;
  esac
fi

case "$NUM" in
  224) rows=2; cols=14 ;;
  256) rows=2; cols=16 ;;
  384) rows=3; cols=16 ;;
  512) rows=4; cols=16 ;;
  1)   rows=1; cols=20 ;;
  *)
      echo >&2 "error: unexpected sha: sha$NUM"
      exit 1
      ;;
esac

color_for_nibble() {
    if [ $# -lt 1 ]; then
        echo >&2 "must pass nibble"
        return 1
    fi

    num=$((0x$1))

    echo -en "\033[48;5;${num}m"
    echo -n " $1 "
    echo -en "\033[0m"
}

sha_prog() {
  local num
  num="$1"
  shift

  case "$OSTYPE" in
    darwin*)
      shasum -a "$num" "$@"
      ;;
    *)
      "sha${num}sum" "$@"
      ;;
  esac
}

sha_prog "$NUM" "$@" | while read hash filename; do
  echo "$hash $filename"
  i=0
  for (( row=0; row < rows; row++ )); do
    for (( col=0; col < cols; col++ )); do
      color_for_nibble "${hash:$i:2}"
      i=$((i + 2))
    done
    echo ''
  done
done

# vim: set sw=2 ts=2 :