Implemented efficient FFI versions of SoundData methods, which are used when the LuaJIT FFI and JIT compiler are present.

src/modules/sound/wrap_SoundData.cpp

@@ -22,11 +22,21 @@
 
 #include "common/wrap_Data.h"
 
+// Shove the wrap_SoundData.lua code directly into a raw string literal.
+static const char sounddata_lua[] =
+#include "wrap_SoundData.lua"
+;
+
 namespace love
 {
 namespace sound
 {
 
+/**
+ * NOTE: Additional wrapper code is in wrap_SoundData.lua. Be sure to keep it
+ * in sync with any changes made to this file!
+ **/
+
 SoundData *luax_checksounddata(lua_State *L, int idx)
 {
 	return luax_checktype<SoundData>(L, idx, SOUND_SOUND_DATA_ID);
@@ -105,7 +115,22 @@ static const luaL_Reg functions[] =
 
 extern "C" int luaopen_sounddata(lua_State *L)
 {
-	return luax_register_type(L, SOUND_SOUND_DATA_ID, functions);
+	// The last argument pushes the type's metatable onto the stack.
+	int ret = luax_register_type(L, SOUND_SOUND_DATA_ID, functions, true);
+
+	// Load and execute SoundData.lua, sending the metatable as an argument.
+	if (ret > 0)
+	{
+		luaL_loadbuffer(L, sounddata_lua, sizeof(sounddata_lua), "SoundData.lua");
+		lua_pushvalue(L, -2);
+		lua_call(L, 1, 0);
+
+		// Pop the metatable.
+		lua_pop(L, 1);
+		ret--;
+	}
+
+	return ret;
 }
 
 } // sound

src/modules/sound/wrap_SoundData.lua

@@ -0,0 +1,116 @@
+R"luastring"--(
+-- DO NOT REMOVE THE ABOVE LINE. It is used to load this file as a C++ string.
+-- There is a matching delimiter at the bottom of the file.
+
+--[[
+Copyright (c) 2006-2015 LOVE Development Team
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+claim that you wrote the original software. If you use this software
+in a product, an acknowledgment in the product documentation would be
+appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+--]]
+
+local SoundData_mt = ...
+
+if type(jit) ~= "table" or not jit.status() then
+	-- LuaJIT's FFI is *much* slower than LOVE's regular methods when the JIT
+	-- compiler is disabled.
+	return
+end
+
+local status, ffi = pcall(require, "ffi")
+if not status then return end
+
+local tonumber, assert = tonumber, assert
+
+local float = ffi.typeof("float")
+local datatypes = {ffi.typeof("uint8_t *"), ffi.typeof("int16_t *")}
+
+local typemaxvals = {0x7F, 0x7FFF}
+
+local _getBitDepth = SoundData_mt.__index.getBitDepth
+local _getSampleCount = SoundData_mt.__index.getSampleCount
+local _getSampleRate = SoundData_mt.__index.getSampleRate
+local _getChannels = SoundData_mt.__index.getChannels
+
+-- Table which holds SoundData objects as keys, and information about the objects
+-- as values. Uses weak keys so the SoundData objects can still be GC'd properly.
+local objectcache = setmetatable({}, {
+	__mode = "k",
+	__index = function(self, sounddata)
+		local bytedepth = _getBitDepth(sounddata) / 8
+		local pointer = ffi.cast(datatypes[bytedepth], sounddata:getPointer())
+
+		local p = {
+			bytedepth = bytedepth,
+			pointer = pointer,
+			size = sounddata:getSize(),
+			maxvalue = typemaxvals[bytedepth],
+			samplecount = _getSampleCount(sounddata),
+			samplerate = _getSampleRate(sounddata),
+			channels = _getChannels(sounddata),
+		}
+
+		self[sounddata] = p
+		return p
+	end,
+})
+
+
+-- Overwrite existing functions with new FFI versions.
+
+function SoundData_mt.__index:getSample(i)
+	local p = objectcache[self]
+	assert(i >= 0 and i < p.size/p.bytedepth, "Attempt to get out-of-range sample!")
+	if p.bytedepth == 2 then
+		-- 16-bit data is stored as signed values internally.
+		return tonumber(p.pointer[i]) / p.maxvalue
+	else
+		-- 8-bit data is stored as unsigned values internally.
+		return (tonumber(p.pointer[i]) - 128) / 127
+	end
+end
+
+function SoundData_mt.__index:setSample(i, sample)
+	local p = objectcache[self]
+	assert(i >= 0 and i < p.size/p.bytedepth, "Attempt to set out-of-range sample!")
+	if p.bytedepth == 2 then
+		-- 16-bit data is stored as signed values internally.
+		p.pointer[i] = sample * p.maxvalue
+	else
+		-- 8-bit data is stored as unsigned values internally.
+		-- The float cast is needed to make values end up the same as in the
+		-- C++ version of this method.
+		p.pointer[i] = ffi.cast(float, (sample * 127) + 128)
+	end
+end
+
+function SoundData_mt.__index:getSampleCount()
+	local p = objectcache[self]
+	return p.samplecount
+end
+
+function SoundData_mt.__index:getSampleRate()
+	local p = objectcache[self]
+	return p.samplerate
+end
+
+function SoundData_mt.__index:getChannels()
+	local p = objectcache[self]
+	return p.channels
+end
+
+-- DO NOT REMOVE THE NEXT LINE. It is used to load this file as a C++ string.
+--)luastring"--"