Backport PUC Lua 5.4's string.{pack,unpack,packsize}

Author: appgurueu

CMakeLists.txt

@@ -288,6 +288,7 @@ find_package(Lua REQUIRED)
 if(NOT USE_LUAJIT)
 	add_subdirectory(lib/bitop)
 endif()
+add_subdirectory(lib/lstrpack)
 add_subdirectory(lib/sha256)
 
 if(BUILD_UNITTESTS OR BUILD_BENCHMARKS)

doc/lua_api.md

@@ -4228,6 +4228,11 @@ Helper functions
     * e.g. `"a,b":split","` returns `{"a","b"}`
 * `string:trim()`: returns the string without whitespace pre- and suffixes
     * e.g. `"\n \t\tfoo bar\t ":trim()` returns `"foo bar"`
+* Utilities for working with binary data:
+    * `string.pack(fmt, ...)`
+    * `string.unpack(fmt, s, [pos])`
+    * `string.packsize(fmt)`
+    * Backported from Lua 5.4, see https://www.lua.org/manual/5.4/manual.html#6.4.2
 * `core.wrap_text(str, limit, as_table)`: returns a string or table
     * Adds newlines to the string to keep it within the specified character
       limit

games/devtest/mods/unittests/misc.lua

@@ -363,3 +363,10 @@ local function test_sandbox()
 	assert(debug.getinfo(function() end, "f").func ~= nil)
 end
 unittests.register("test_sandbox", test_sandbox)
+
+local function test_str_pack_unpack()
+	local fmt = "d"
+	assert(fmt:packsize() == 8)
+	assert(fmt:unpack(fmt:pack(42.3)) == 42.3)
+end
+unittests.register("test_str_pack_unpack", test_str_pack_unpack)

lib/lstrpack/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_library(lstrpack STATIC lstrpack.c)
+target_include_directories(lstrpack
+	PUBLIC
+		${CMAKE_CURRENT_SOURCE_DIR}
+	PRIVATE
+		${LUA_INCLUDE_DIR}
+)

lib/lstrpack/LICENSE.txt

@@ -0,0 +1,20 @@
+Copyright (C) 1994-2025 Lua.org, PUC-Rio.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.