Prototype for replacement encoding

lib/Encoding/Replacement.php

@@ -0,0 +1,125 @@
+<?php
+/** @license MIT
+ * Copyright 2018 J. King et al.
+ * See LICENSE and AUTHORS files for details */
+
+declare(strict_types=1);
+namespace MensBeam\Intl\Encoding;
+
+class Replacement implements Encoding {
+    const NAME = "replacement";
+    const LABELS = [
+        "csiso2022kr",
+        "hz-gb-2312",
+        "iso-2022-cn",
+        "iso-2022-cn-ext",
+        "iso-2022-kr",
+        "replacement",
+    ];
+
+    protected $len = 0;
+    protected $done = false;
+    protected $fatal = false;
+
+    public $posErr = 0;
+
+    public function __construct(string $string, bool $fatal = false, bool $allowSurrogates = false) {
+        $this->len = strlen($string);
+        $this->fatal = $fatal;
+    }
+
+    public function posByte(): int {
+        return $this->done ? $this->len : 0;
+    }
+
+    public function posChar(): int {
+        return $this->done ? 1 : 0;
+    }
+
+    public function nextChar(): string {
+        if (!$this->eof()) {
+            try {
+                return $this->peekChar();
+            } finally {
+                $this->done = true;
+                $this->posErr = 1;
+            }
+        }
+        return "";
+    }
+
+    public function nextCode() {
+        if (!$this->eof()) {
+            try {
+                return $this->peekCode();
+            } finally {
+                $this->done = true;
+                $this->posErr = 1;
+            }
+        }
+        return false;
+    }
+
+    public function seek(int $distance): int {
+        if ($distance > 0) {
+            if (!$this->eof()) {
+                $distance--;
+                $this->nextCode();
+            }
+        } elseif ($distance < 0) {
+            if ($this->eof()) {
+                $distance++;
+                $this->rewind();
+            }
+        }
+        return $distance;
+    }
+
+    public function rewind() {
+        $this->done = false;
+    }
+
+    public function peekChar(int $num = 1): string {
+        if (!$this->eof()) {
+            if ($this->fatal) {
+                throw new DecoderException("Unable to decode string", self::E_INVALID_BYTE);
+            }
+            return "\u{FFFD}";
+        }
+        return "";
+    }
+
+    public function peekCode(int $num = 1): array {
+        if (!$this->eof()) {
+            if ($this->fatal) {
+                throw new DecoderException("Unable to decode string", self::E_INVALID_BYTE);
+            }
+            return [0xFFFD];
+        }
+        return [];
+    }
+
+    public function lenByte(): int {
+        return $this->len;
+    }
+
+    public function lenChar(): int {
+        return (int) ($this->len > 0);
+    }
+
+    public function eof(): bool {
+        return $this->done || $this->len === 0;
+    }
+
+    public function chars(): \Generator {
+        if (!$this->eof()) {
+            yield 0 => $this->nextChar();
+        }
+    }
+
+    public function codes(): \Generator {
+        if (!$this->eof()) {
+            yield 0 => $this->nextCode();
+        }
+    }
+}