core: rename mbgl directories to mln (#4511)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

include/mln/util/char_array_buffer.hpp

@@ -0,0 +1,57 @@
+#pragma once
+
+#include <streambuf>
+
+namespace mln {
+namespace util {
+
+// ref https://artofcode.wordpress.com/2010/12/12/deriving-from-stdstreambuf/
+
+class CharArrayBuffer : public std::streambuf {
+public:
+    CharArrayBuffer(char const* data, std::size_t size)
+        : begin_(data),
+          end_(data + size),
+          current_(data) {}
+
+private:
+    int_type underflow() final {
+        if (current_ == end_) {
+            return traits_type::eof();
+        }
+        return traits_type::to_int_type(*current_);
+    }
+
+    int_type uflow() final {
+        if (current_ == end_) {
+            return traits_type::eof();
+        }
+        return traits_type::to_int_type(*current_++);
+    }
+
+    int_type pbackfail(int_type ch) final {
+        if (current_ == begin_ || (ch != traits_type::eof() && ch != current_[-1])) {
+            return traits_type::eof();
+        }
+        return traits_type::to_int_type(*--current_);
+    }
+
+    std::streamsize showmanyc() final { return end_ - current_; }
+
+    pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode) final {
+        if (dir == std::ios_base::beg)
+            current_ = std::min(begin_ + off, end_);
+        else if (dir == std::ios_base::cur)
+            current_ = std::min(current_ + off, end_);
+        else
+            current_ = std::max(end_ - off, begin_); // dir == std::ios_base::end
+        return {off_type(current_ - begin_)};
+    }
+
+    char const* const begin_;
+    char const* const end_;
+    char const* current_;
+};
+
+} // namespace util
+} // namespace mln