1 files changed, 84 insertions, 0 deletions
diff --git a/plugins/MirLua/Modules/ffi/src/README.md b/plugins/MirLua/Modules/ffi/src/README.md
new file mode 100644
index 0000000000..df6ffba165
--- /dev/null
+++ b/plugins/MirLua/Modules/ffi/src/README.md
@@ -0,0 +1,84 @@
+About
+-----
+This is a library for calling C function and manipulating C types from lua. It
+is designed to be interface compatible with the FFI library in LuaJIT (see
+http://luajit.org/ext_ffi.html). It can parse C function declarations and
+struct definitions that have been directly copied out of C header files and
+into lua source as a string.
+
+This is a fork of https://github.com/jmckaskill/luaffi
+
+Source
+------
+https://github.com/facebook/luaffifb
+
+Platforms
+---------
+Currently supported:
+- Linux x86/x64
+- OS X x86/x64
+
+Runs with both Lua 5.1 and Lua 5.2.
+
+Build
+-----
+In a terminal:
+
+```bash
+git clone https://github.com/facebook/luaffifb
+cd luaffifb
+luarocks make
+```
+
+Documentation
+-------------
+This library is designed to be source compatible with LuaJIT's FFI extension. The documentation at http://luajit.org/ext_ffi.html describes the API and semantics.
+
+Pointer Comparison
+------------
+Use `ffi.NULL` instead of `nil` when checking for `NULL` pointers.
+```lua
+  ffi.new('void *', 0) == ffi.NULL -- true
+```
+
+Known Issues
+------------
+- Comparing a ctype pointer to `nil` doesn't work the same as in LuaJIT (see above).
+  This is unfixable with the current metamethod semantics.
+- Constant expressions can't handle non integer intermediate values (eg
+  offsetof won't work because it manipulates pointers)
+- Not all metamethods work with Lua 5.1 (eg char* + number). This is due to
+  the way metamethods are looked up with mixed types in Lua 5.1. If you need
+this upgrade to Lua 5.2 or use boxed numbers (uint64_t and uintptr_t).
+- All bitfields are treated as unsigned (does anyone even use signed
+  bitfields?). Note that "int s:8" is unsigned on unix x86/x64, but signed on
+windows.
+
+
+How it works
+------------
+Types are represented by a struct ctype structure and an associated user value
+table. The table is shared between all related types for structs, unions, and
+functions. It's members have the types of struct members, function argument
+types, etc. The struct ctype structure then contains the modifications from
+the base type (eg number of pointers, array size, etc).
+
+Types are pushed into lua as a userdata containing the struct ctype with a
+user value (or fenv in 5.1) set to the shared type table.
+
+Boxed cdata types are pushed into lua as a userdata containing the struct
+cdata structure (which contains the struct ctype of the data as its header)
+followed by the boxed data.
+
+The functions in `ffi.C` provide the `cdata` and `ctype` metatables and ffi.*
+functions which manipulate these two types.
+
+C functions (and function pointers) are pushed into lua as a lua c function
+with the function pointer cdata as the first upvalue. The actual code is JITed
+using dynasm (see call_x86.dasc). The JITed code does the following in order:
+
+1. Calls the needed unpack functions in `ffi.C` placing each argument on the HW stack
+2. Updates `errno`
+3. Performs the C call
+4. Retrieves `errno`
+5. Pushes the result back into lua from the HW register or stack