diff --git a/src/abr.cpp b/src/abr.cpp
index b066a9b..02896ba 100644
--- a/src/abr.cpp
+++ b/src/abr.cpp
@@ -349,7 +349,7 @@ std::vector<std::shared_ptr<Brush>> ABR::compute_brushes(const std::string& path
     return ret;
 }
 
-std::shared_ptr<ABR::VMArray> ABR::parse_vmem()
+std::shared_ptr<SerializedStreamReader::VMArray> SerializedStreamReader::parse_vmem()
 {
     // Virtual Memory Array List
     auto vmem_version = ru32(); // = 3
@@ -416,7 +416,7 @@ std::shared_ptr<ABR::VMArray> ABR::parse_vmem()
     return ret;
 }
 
-std::shared_ptr<ABR::List> ABR::parse_vlls()
+std::shared_ptr<SerializedStreamReader::List> SerializedStreamReader::parse_vlls()
 {
     auto ret = std::make_shared<List>();
     auto count = ru32();
@@ -432,7 +432,7 @@ std::shared_ptr<ABR::List> ABR::parse_vlls()
     return ret;
 }
 
-std::shared_ptr<ABR::String> ABR::parse_text()
+std::shared_ptr<SerializedStreamReader::String> SerializedStreamReader::parse_text()
 {
     auto ret = std::make_shared<String>();
     ret->value = rwstring();
@@ -440,7 +440,7 @@ std::shared_ptr<ABR::String> ABR::parse_text()
     return ret;
 }
 
-std::shared_ptr<ABR::Descriptor> ABR::parse_objc()
+std::shared_ptr<SerializedStreamReader::Descriptor> SerializedStreamReader::parse_objc()
 {
     auto ret = std::make_shared<Descriptor>();
     ret->name = rwstring();
@@ -462,7 +462,7 @@ std::shared_ptr<ABR::Descriptor> ABR::parse_objc()
     return ret;
 }
 
-std::shared_ptr<ABR::UnitFloat> ABR::parse_untf()
+std::shared_ptr<SerializedStreamReader::UnitFloat> SerializedStreamReader::parse_untf()
 {
     auto ret = std::make_shared<UnitFloat>();
     ret->unit = rstring(4);
@@ -471,7 +471,7 @@ std::shared_ptr<ABR::UnitFloat> ABR::parse_untf()
     return ret;
 }
 
-std::shared_ptr<ABR::Boolean> ABR::parse_bool()
+std::shared_ptr<SerializedStreamReader::Boolean> SerializedStreamReader::parse_bool()
 {
     auto ret = std::make_shared<Boolean>();
     ret->value = ru8();
@@ -479,7 +479,7 @@ std::shared_ptr<ABR::Boolean> ABR::parse_bool()
     return ret;
 }
 
-std::shared_ptr<ABR::Integer> ABR::parse_long()
+std::shared_ptr<SerializedStreamReader::Integer> SerializedStreamReader::parse_long()
 {
     auto ret = std::make_shared<Integer>();
     ret->value = ru32();
@@ -487,7 +487,7 @@ std::shared_ptr<ABR::Integer> ABR::parse_long()
     return ret;
 }
 
-std::shared_ptr<ABR::Double> ABR::parse_doub()
+std::shared_ptr<SerializedStreamReader::Double> SerializedStreamReader::parse_doub()
 {
     auto ret = std::make_shared<Double>();
     ret->value = rdbl();
@@ -495,7 +495,7 @@ std::shared_ptr<ABR::Double> ABR::parse_doub()
     return ret;
 }
 
-std::shared_ptr<ABR::Enum> ABR::parse_enum()
+std::shared_ptr<SerializedStreamReader::Enum> SerializedStreamReader::parse_enum()
 {
     auto ret = std::make_shared<Enum>();
     ret->type = rkey_or_string();
@@ -504,26 +504,26 @@ std::shared_ptr<ABR::Enum> ABR::parse_enum()
     return ret;
 }
 
-std::shared_ptr<ABR::RawData> ABR::parse_tdta()
+std::shared_ptr<SerializedStreamReader::RawData> SerializedStreamReader::parse_tdta()
 {
     auto ret = std::make_shared<RawData>();
     ret->data = rraw();
     return ret;
 }
 
-ABR::ABR()
+SerializedStreamReader::SerializedStreamReader()
 {
-    m_parser_table = std::map<std::string, std::function<ABR::Type::Ref()>>
+    m_parser_table = std::map<std::string, std::function<SerializedStreamReader::Type::Ref()>>
     {
-        { "VlLs", std::bind(&ABR::parse_vlls, this) },
-        { "TEXT", std::bind(&ABR::parse_text, this) },
-        { "Objc", std::bind(&ABR::parse_objc, this) },
-        { "UntF", std::bind(&ABR::parse_untf, this) },
-        { "bool", std::bind(&ABR::parse_bool, this) },
-        { "long", std::bind(&ABR::parse_long, this) },
-        { "doub", std::bind(&ABR::parse_doub, this) },
-        { "enum", std::bind(&ABR::parse_enum, this) },
-        { "tdta", std::bind(&ABR::parse_tdta, this) },
+        { "VlLs", std::bind(&SerializedStreamReader::parse_vlls, this) },
+        { "TEXT", std::bind(&SerializedStreamReader::parse_text, this) },
+        { "Objc", std::bind(&SerializedStreamReader::parse_objc, this) },
+        { "UntF", std::bind(&SerializedStreamReader::parse_untf, this) },
+        { "bool", std::bind(&SerializedStreamReader::parse_bool, this) },
+        { "long", std::bind(&SerializedStreamReader::parse_long, this) },
+        { "doub", std::bind(&SerializedStreamReader::parse_doub, this) },
+        { "enum", std::bind(&SerializedStreamReader::parse_enum, this) },
+        { "tdta", std::bind(&SerializedStreamReader::parse_tdta, this) },
     };
 }
 
@@ -532,7 +532,7 @@ bool ABR::open(const std::string& path)
     Asset asset;
     if (asset.open(path.c_str()))
     {
-        init(asset.read_all(), asset.m_len, BinaryStream::ByteOrder::BigEndian);
+        init(asset.read_all(), asset.m_len, BinaryStreamReader::ByteOrder::BigEndian);
         auto version_major = ru16();
         auto version_minor = ru16();
         LOG("ABR %d.%d\n", version_major, version_minor);
diff --git a/src/abr.h b/src/abr.h
index 97b1eb4..893e675 100644
--- a/src/abr.h
+++ b/src/abr.h
@@ -20,9 +20,61 @@ public:
 
         return bint.c[0] == 1 ? ByteOrder::BigEndian : ByteOrder::LittleEndian;
     }
-    BinaryStream(const BinaryStream&) = delete;
-    BinaryStream() = default;
-    ~BinaryStream()
+    template<typename T> T swap(T x)
+    {
+#if _MSC_VER >= 1400
+
+        if (sizeof(T) == 2)
+        {
+            auto y = _byteswap_ushort(*reinterpret_cast<uint16_t*>(&x));
+            return *reinterpret_cast<T*>(&y);
+        }
+        else if (sizeof(T) == 4)
+        {
+            auto y = _byteswap_ulong(*reinterpret_cast<uint32_t*>(&x));
+            return *reinterpret_cast<T*>(&y);
+        }
+        else if (sizeof(T) == 8)
+        {
+            auto y = _byteswap_uint64(*reinterpret_cast<uint64_t*>(&x));
+            return *reinterpret_cast<T*>(&y);
+        }
+#else
+        auto p = reinterpret_cast<uint8_t*>(&x);
+        if (sizeof(T) == 2)
+        {
+            std::swap(p[0], p[1]);
+        }
+        else if (sizeof(T) == 4)
+        {
+            std::swap(p[0], p[3]);
+            std::swap(p[1], p[2]);
+        }
+        else if (sizeof(T) == 8)
+        {
+            std::swap(p[0], p[7]);
+            std::swap(p[1], p[6]);
+            std::swap(p[2], p[5]);
+            std::swap(p[3], p[4]);
+        }
+        else
+        {
+            static_assert(true, "Should not reach here");
+        }
+        return x;
+#endif
+    }
+protected:
+    bool m_swap = false;
+    ByteOrder m_byte_order = ByteOrder::Host;
+};
+
+class BinaryStreamReader : public BinaryStream
+{
+public:
+    BinaryStreamReader(const BinaryStreamReader&) = delete;
+    BinaryStreamReader() = default;
+    ~BinaryStreamReader()
     {
         m_ptr = m_cur = nullptr;
         m_size = 0;
@@ -39,7 +91,7 @@ public:
     // snap to the next 4-alignment
     void snap() { if ((size_t)m_cur % 4 != 0) m_cur += 4 - (size_t)m_cur % 4; }
     bool eof() { return std::distance(m_ptr, m_cur) >= m_size; }
-    bool has_data(size_t sz) { return std::distance(m_ptr, m_cur + sz) < m_size; }
+    bool has_data(size_t sz) { return std::distance(m_ptr, m_cur + sz) <= m_size; }
     uint8_t  ru8()  { return read<uint8_t>(); }
     uint16_t ru16() { return m_swap ? swap(read<uint16_t>()) : read<uint16_t>(); }
     uint32_t ru32() { return m_swap ? swap(read<uint32_t>()) : read<uint32_t>(); }
@@ -102,9 +154,6 @@ public:
         {
             n = ri8();
             j++;
-            // force sign
-            if (n >= 128)
-                n -= 256; // can this even happen?
             // copy the following char -n + 1 times
             if (n < 0)
             {
@@ -151,60 +200,115 @@ protected:
         }
         return ret;
     }
-    template<typename T> T swap(T x)
-    {
-#if _MSC_VER >= 1400
-
-        if (sizeof(T) == 2)
-        {
-            auto y = _byteswap_ushort(*reinterpret_cast<uint16_t*>(&x));
-            return *reinterpret_cast<T*>(&y);
-        }
-        else if (sizeof(T) == 4)
-        {
-            auto y = _byteswap_ulong(*reinterpret_cast<uint32_t*>(&x));
-            return *reinterpret_cast<T*>(&y);
-        }
-        else if (sizeof(T) == 8)
-        {
-            auto y = _byteswap_uint64(*reinterpret_cast<uint64_t*>(&x));
-            return *reinterpret_cast<T*>(&y);
-        }
-#else
-        auto p = reinterpret_cast<uint8_t*>(&x);
-        if (sizeof(T) == 2)
-        {
-            std::swap(p[0], p[1]);
-        }
-        else if (sizeof(T) == 4)
-        {
-            std::swap(p[0], p[3]);
-            std::swap(p[1], p[2]);
-        }
-        else if (sizeof(T) == 8)
-        {
-            std::swap(p[0], p[7]);
-            std::swap(p[1], p[6]);
-            std::swap(p[2], p[5]);
-            std::swap(p[3], p[4]);
-        }
-        else
-        {
-            static_assert(true, "Should not reach here");
-        }
-        return x;
-#endif
-    }
 private:
     uint8_t *m_ptr = nullptr;
     uint8_t *m_cur = nullptr;
     size_t m_size = 0;
-    bool m_swap = false;
-    ByteOrder m_byte_order = ByteOrder::Host;
 };
 
-class ABR : private BinaryStream
+class BinaryStreamWriter : public BinaryStream
 {
+public:
+    std::vector<uint8_t> m_data;
+    BinaryStreamWriter(const BinaryStreamWriter&) = delete;
+    BinaryStreamWriter() = default;
+    ~BinaryStreamWriter() = default;
+    void init(ByteOrder byte_order = ByteOrder::Host)
+    {
+        m_byte_order = byte_order;
+        m_swap = byte_order == ByteOrder::Host ? false : byte_order != sys_order();
+    }
+    //size_t pos() { return std::distance(m_ptr, m_cur); }
+    void skip(size_t bytes, uint8_t fill = 0) { m_data.resize(m_data.size() + bytes); }
+    // snap to the next 4-alignment
+    void snap() { if ((size_t)m_data.size() % 4 != 0) m_data.resize(m_data.size() + 4 - (size_t)m_data.size() % 4); }
+    //bool eof() { return std::distance(m_ptr, m_cur) >= m_size; }
+    //bool has_data(size_t sz) { return std::distance(m_ptr, m_cur + sz) < m_size; }
+    void wu8 (uint8_t v ) { return write<uint8_t>(v); }
+    void wu16(uint16_t v) { return m_swap ? write(swap(v)) : write(v); }
+    void wu32(uint32_t v) { return m_swap ? write(swap(v)) : write(v); }
+    void wu64(uint64_t v) { return m_swap ? write(swap(v)) : write(v); }
+    void wi8 (int8_t v  ) { return write<int8_t>(v); }
+    void wi16(int16_t v ) { return m_swap ? write(swap(v)) : write(v); }
+    void wi32(int32_t v ) { return m_swap ? write(swap(v)) : write(v); }
+    void wi64(int64_t v ) { return m_swap ? write(swap(v)) : write(v); }
+    void wflt(float v   ) { return m_swap ? write(swap(v)) : write(v); }
+    void wdbl(double v  ) { return m_swap ? write(swap(v)) : write(v); }
+    //std::string pick(size_t chars) { return { (char*)m_cur, chars }; }
+    void wstring(std::string s)
+    {
+        wu32(s.size());
+        write(s.data(), s.size());
+    }
+    void wwstring(std::wstring s)
+    {
+        wu32(s.size());
+        std::wstring_convert<std::codecvt_utf16<wchar_t, 0x10ffff>> converter;
+        wstring(converter.to_bytes(s));
+    }
+    void wpascal(std::string s)
+    {
+        wu8(s.size());
+        write(s.data(), s.size());
+    }
+    void wraw(std::vector<uint8_t> raw)
+    {
+        wu32(raw.size());
+        write(raw.data(), raw.size());
+    }
+    void wrle(std::vector<uint8_t> data)
+    {
+        int idx = 0;
+        auto ptr = data.data();
+        
+        // find the next sequence and return the position
+        auto next_seq = [&] () -> std::pair<size_t, size_t> {
+            size_t i = idx;
+            while (i < data.size() - 1)
+            {
+                size_t count = 0;
+                for (size_t j = i + 1; j < data.size() && data[i] == data[j]; j++)
+                    count++;
+                if (count > 0)
+                    return { i, count + 1 };
+                i++;
+            }
+            return { i + 1, 0 };
+        };
+
+        while (idx < data.size())
+        {
+            auto seq = next_seq();
+            // non sequence chars
+            if (seq.first - idx > 0)
+            {
+                wi8(seq.first - idx - 1);
+                write(ptr + idx, seq.first - idx);
+            }
+            if (seq.second > 0)
+            {
+                wi8(-(int8_t)(seq.second - 1));
+                write(ptr[seq.first]);
+            }
+            idx = seq.first + seq.second;
+        }
+    }
+protected:
+    template<typename T> void write(T x)
+    {
+        uint8_t* bytes = reinterpret_cast<uint8_t*>(&x);
+        m_data.insert(m_data.end(), bytes, bytes + sizeof(T));
+    }
+    template<typename T> void write(const T* ptr, size_t size)
+    {
+        const uint8_t* bytes = reinterpret_cast<const uint8_t*>(ptr);
+        m_data.insert(m_data.end(), bytes, bytes + size * sizeof(T));
+    }
+};
+
+class SerializedStream
+{
+public:
     struct Type
     {
         using Vec = std::vector<std::shared_ptr<Type>>;
@@ -410,11 +514,29 @@ class ABR : private BinaryStream
             }
             else
             {
-                printf("Error image with %d channels\n", channels.size());
+                LOG("Error image with %d channels\n", channels.size());
             }
             return nullptr;
         }
     };
+};
+
+class SerializedStreamReader : public SerializedStream, public BinaryStreamReader
+{
+public:
+    std::shared_ptr<VMArray>    parse_vmem(); // Parse Virtual Memory Array List
+    std::shared_ptr<List>       parse_vlls();
+    std::shared_ptr<String>     parse_text();
+    std::shared_ptr<Descriptor> parse_objc();
+    std::shared_ptr<UnitFloat>  parse_untf();
+    std::shared_ptr<Boolean>    parse_bool();
+    std::shared_ptr<Integer>    parse_long();
+    std::shared_ptr<Double>     parse_doub();
+    std::shared_ptr<Enum>       parse_enum();
+    std::shared_ptr<RawData>    parse_tdta();
+
+    std::map<std::string /*key*/, std::function<Type::Ref()>> m_parser_table;
+    SerializedStreamReader();
 
     std::string rkey_or_string()
     {
@@ -449,30 +571,18 @@ class ABR : private BinaryStream
         }
         return nullptr;
     }
+};
 
+class ABR : private SerializedStreamReader
+{
     bool section_desc();
     bool section_samp();
     bool section_patt();
-    
-    std::shared_ptr<VMArray>    parse_vmem(); // Parse Virtual Memory Array List
-    std::shared_ptr<List>       parse_vlls();
-    std::shared_ptr<String>     parse_text();
-    std::shared_ptr<Descriptor> parse_objc();
-    std::shared_ptr<UnitFloat>  parse_untf();
-    std::shared_ptr<Boolean>    parse_bool();
-    std::shared_ptr<Integer>    parse_long();
-    std::shared_ptr<Double>     parse_doub();
-    std::shared_ptr<Enum>       parse_enum();
-    std::shared_ptr<RawData>    parse_tdta();
-
-    std::map<std::string /*key*/, std::function<Type::Ref()>> m_parser_table;
-
 public:
     std::vector<std::shared_ptr<Descriptor>> m_presets;
     std::map<std::string /*uid*/, std::shared_ptr<Image>> m_patterns;
     std::map<std::string /*uid*/, std::shared_ptr<Image>> m_samples;
 
-    ABR();
     bool open(const std::string& path);
     std::vector<std::shared_ptr<Brush>> compute_brushes(const std::string& path);
 };