Initial commit

src/Huffman/Codec.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace NoccyLabs\React\Http2\Huffman;
+
+class Codec
+{
+    private Dictionary $dictionary;
+
+    const CODE_EOS = 256;
+
+    public function __construct(Dictionary $dictionary)
+    {
+        $this->dictionary = $dictionary;
+    }
+
+    public function decode(string $data): ?string
+    {
+        $in = array_map("ord", str_split($data));
+        $out = [];
+        $bits = '';
+        for ($ch = 0; $ch < count($in); $ch++) {
+            $bits .= str_pad(decbin($in[$ch]), 8, "0", STR_PAD_LEFT);
+            while (($code = $this->dictionary->match($bits)) !== null) {
+                if ($code === self::CODE_EOS) break(2);
+                $out[] = $code;
+            }
+        }
+        return join("", array_map("chr", $out));
+    }
+
+    public function encode(string $data): ?string
+    {
+        $in = array_map("ord", str_split($data));
+        //$in[] = self::CODE_EOS;
+        $out = [];
+        $bits = '';
+        for ($ch = 0; $ch < count($in); $ch++) {
+            $bits .= $this->dictionary->pattern($in[$ch]);
+            while (strlen($bits) >= 8) {
+                $out[] = bindec(substr($bits, 0, 8));
+                $bits = substr($bits, 8);
+            }
+        }
+        if (strlen($bits) > 0) {
+            $out[] = bindec(str_pad($bits, 8, "1", STR_PAD_RIGHT));
+        }
+        return join("", array_map("chr", $out));
+    }
+
+}