Load iw4x zones for iw4

src/ZoneLoading/Loading/Processor/ProcessorIW4xDecryption.cpp

@@ -0,0 +1,45 @@
+#include "ProcessorIW4xDecryption.h"
+
+#include <cassert>
+
+ProcessorIW4xDecryption::ProcessorIW4xDecryption()
+    : m_last_byte(0u)
+{
+}
+
+uint8_t ProcessorIW4xDecryption::RotateLeft(const uint8_t value, const unsigned count)
+{
+    assert(count < sizeof(value) * 8);
+    return static_cast<uint8_t>(value << count | (value >> ((sizeof(value) * 8) - count)));
+}
+
+uint8_t ProcessorIW4xDecryption::RotateRight(uint8_t value, const unsigned count)
+{
+    assert(count < sizeof(value) * 8);
+    return static_cast<uint8_t>(value >> count | (value << ((sizeof(value) * 8) - count)));
+}
+
+size_t ProcessorIW4xDecryption::Load(void* buffer, const size_t length)
+{
+    const auto readLen = m_base_stream->Load(buffer, length);
+
+    auto* charBuffer = static_cast<uint8_t*>(buffer);
+    for(auto i = 0u; i < readLen; i++)
+    {
+        auto value = charBuffer[i];
+        value ^= m_last_byte;
+        value = RotateLeft(value, 4);
+        value ^= -1;
+        value = RotateRight(value, 6);
+
+        charBuffer[i] = value;
+        m_last_byte = value;
+    }
+
+    return readLen;
+}
+
+int64_t ProcessorIW4xDecryption::Pos()
+{
+    return m_base_stream->Pos();
+}

src/ZoneLoading/Loading/Processor/ProcessorIW4xDecryption.h

@@ -0,0 +1,16 @@
+#pragma once
+#include "Loading/StreamProcessor.h"
+
+class ProcessorIW4xDecryption final : public StreamProcessor
+{
+    uint8_t m_last_byte;
+
+    static uint8_t RotateLeft(uint8_t value, unsigned count);
+    static uint8_t RotateRight(uint8_t value, unsigned count);
+
+public:
+    ProcessorIW4xDecryption();
+
+    size_t Load(void* buffer, size_t length) override;
+    int64_t Pos() override;
+};

src/ZoneLoading/Loading/Processor/ProcessorInflate.cpp

@@ -69,7 +69,7 @@ public:
                 throw InvalidCompressionException();
         }
 
-        return m_stream.avail_out;
+        return length - m_stream.avail_out;
     }
 };