Data commit

Task/Huffman-coding/UNIX-Shell/huffman-coding.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+set -eu
+
+# make scratch directory
+t="$(mktemp -d)"
+cd "${t:?mktemp failed}"
+trap 'rm -r -- "$t"' EXIT
+
+# get character frequencies
+declare -a freq=()
+while read addr line; do
+  for c in $line; do
+    : $((freq[8#$c]++))
+  done
+done < <(od -b -v)
+
+# convert freqs into a bucket queue
+declare -i i=0
+for c in ${!freq[@]}; do
+  fn="${freq[c]}.$((i++))"
+  echo "$c:${freq[c]}" >"$fn"
+done
+
+top2() { ls | sort -t. -k1,1n -k2,2n | sed 2q; }
+set -- $(top2)
+while [[ $# -gt 1 ]]; do
+  declare -i l="${1%%.*}" r="${2%%.*}" # combine weights into
+  fn="$((l + r)).$((i++))"             # ... new node weight
+  mkdir "$fn"
+  mv "$1" "$fn/0"
+  mv "$2" "$fn/1"
+  set -- $(top2)
+done
+
+echo -e "Symbol\tWeight\tHuffman Code"
+cd "$fn"
+find . -type f -exec grep . {} + |
+  tr -d ./ |
+  awk -F: '{printf "%c\t%d\t%s\n", $2, $3, $1}' |
+  sort -k 2,2nr -k 3,3n