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fix: potential alignment issues on take
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-17
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‎.github/workflows/ci.yml

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@@ -11,7 +11,7 @@ on:
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- "docs/**"
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env:
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ROCKSPEC_VERSION: 0.0.2
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ROCKSPEC_VERSION: 0.0.3
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DEV_ROCKSPEC: lua-cryptorandom-dev-1.rockspec
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jobs:

‎README.md

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@@ -14,20 +14,11 @@
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>
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> ```lua-cryptorandom``` is implemented in C, and also compiles as C++.
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## Use cases
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Many security operations rely on high-quality randomization services to avoid reproducibility and remain resistant to reverse engineering:
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* randomized password generation;
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* nonces (numbers used once) generation;
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* initialization vectors;
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* salts in passwords before hashing;
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* tokenization (*token generation*) to represent sensitive data;
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* secure random sampling in statistical analysis.
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## Table of Contents
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* [Installation](#installation)
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* [Usage](#usage)
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* [Use cases](#use-cases)
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* [Methods](#methods)
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* [bytes](#bytes)
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* [integer](#integer)
@@ -66,6 +57,69 @@ Assuming that [LuaRocks](https://luarocks.org) is properly installed and configu
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luarocks install lua-cryptorandom
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```
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## Usage
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* How to generate random bytes
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```lua
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local random = require("lua-cryptorandom")
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-- number of bytes to generate
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local n = 10
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local bytes, err = random.bytes(n)
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if (bytes == nil) then
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print("error code: ", err)
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else
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assert(n == #bytes, "Unexpected number of bytes")
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-- print each byte
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for i, b in ipairs(bytes) do
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print(i, ("0x%02X"):format(b))
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end
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end
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```
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* How to generate a random integer
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```lua
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local random = require("lua-cryptorandom")
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local take, err = random.take()
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if (take == nil) then
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print("error code: ", err)
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else
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print("take: ", take)
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end
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```
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* How to generate a random float number
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```lua
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local random = require("lua-cryptorandom")
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local number, err = random.number()
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if (number == nil) then
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print("error code: ", err)
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else
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print("number: ", number)
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end
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```
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## Use cases
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Many security operations rely on high-quality randomization services to avoid reproducibility and remain resistant to reverse engineering:
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* randomized password generation;
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* nonces (numbers used once) generation;
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* initialization vectors;
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* salts in passwords before hashing;
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* tokenization (*token generation*) to represent sensitive data;
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* secure random sampling in statistical analysis.
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## Methods
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> [!IMPORTANT]
@@ -176,10 +230,13 @@ luarocks install lua-cryptorandom
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>
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> This section mostly applies to users running a customized build of Lua.
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* The error code (second return value) on each method might deliver a value different than the one returned by the underlying library. This condition might happen when the Lua type ```lua_Integer``` is shorter than an ```unsigned long``` in size. Even though it can be achieved on personalized builds of Lua (e.g.: Lua compiled as ANSI C on some platforms), the usual build of Lua should be safe for most users and platforms.
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* The error code (second return value) on each method might deliver a value different than the one returned by the underlying library. This condition might happen when the Lua type ```lua_Integer``` is shorter than an ```unsigned long``` in size. Even though it can be achieved on personalized builds of Lua (e.g.: Lua compiled as C89 on some platforms), the usual build of Lua should be safe for most users and platforms.
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## Change log
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* v0.0.3:
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* Using unions on [take](#take) to avoid alignment issues;
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* Added the [Usage](#usage) section on README.
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* v0.0.2: Prevent the generation of ```NaN``` and positive/negative infinity values in the function [number](#number).
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* v0.0.1: Initial release.
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‎rockspecs/lua-cryptorandom-0.0.3-1.rockspec

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package = "lua-cryptorandom"
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version = "0.0.3-1"
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source = {
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url = "git+https://github.com/luau-project/lua-cryptorandom",
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tag = "v0.0.3"
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}
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description = {
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homepage = "https://github.com/luau-project/lua-cryptorandom",
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summary = [[Generate cryptographically secure pseudo random numbers for Lua]],
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detailed = [=[
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lua-cryptorandom is a lightweight, native library for Lua aimed to generate cryptographically secure pseudo random numbers, using trusted sources of randomness provided by the operating system.
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Visit the repository for more information.]=],
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license = "MIT"
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}
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dependencies = {
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"lua >= 5.1"
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}
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local function external_dependencies_plat()
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return {
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["CRYPTO"] = {
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header = "openssl/rand.h"
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}
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}
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end
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external_dependencies = {
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platforms = {
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linux = external_dependencies_plat(),
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freebsd = external_dependencies_plat(),
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openbsd = external_dependencies_plat(),
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netbsd = external_dependencies_plat(),
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dragonfly = external_dependencies_plat()
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}
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}
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local function build_plat(plat)
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if (plat == "macosx" or plat == "macos") then
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return {
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type = "make",
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makefile = "Makefile.macosx",
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build_variables = {
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CFLAGS = "$(CFLAGS)",
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LIBFLAG = "$(LIBFLAG)",
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CFLAGS_EXTRA = "-DLUA_CRYPTORANDOM_BUILD_SHARED -DLUA_CRYPTORANDOM_USE_APPLE",
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LIBFLAG_EXTRA = "-framework Security",
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LUA_INCDIR = "$(LUA_INCDIR)",
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OBJ_EXTENSION = "$(OBJ_EXTENSION)",
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LIB_EXTENSION = "$(LIB_EXTENSION)"
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},
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install_variables = {
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INSTALL_PREFIX = "$(PREFIX)",
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INSTALL_LIBDIR = "$(LIBDIR)",
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LUA_VERSION = "$(LUA_VERSION)",
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LIB_EXTENSION = "$(LIB_EXTENSION)"
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}
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}
62+
elseif (plat == "windows" or plat == "cygwin") then
63+
return {
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type = "builtin",
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modules = {
66+
["lua-cryptorandom"] = {
67+
sources = { "src/lua-cryptorandom.c" },
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libraries = { "bcrypt" },
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defines = { "LUA_CRYPTORANDOM_BUILD_SHARED", "LUA_CRYPTORANDOM_USE_WIN32" },
70+
incdirs = { "src" },
71+
libdirs = { }
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}
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}
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}
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elseif (plat == "linux" or plat == "bsd") then
76+
return {
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type = "builtin",
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modules = {
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["lua-cryptorandom"] = {
80+
sources = { "src/lua-cryptorandom.c" },
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libraries = { "crypto" },
82+
defines = { "LUA_CRYPTORANDOM_BUILD_SHARED", "LUA_CRYPTORANDOM_USE_OPENSSL" },
83+
incdirs = { "src", "$(CRYPTO_INCDIR)" },
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libdirs = { "$(CRYPTO_LIBDIR)" }
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}
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}
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}
88+
else
89+
error("Unknown platform", 2)
90+
end
91+
end
92+
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build = {
94+
platforms = {
95+
macosx = build_plat("macosx"),
96+
macos = build_plat("macos"),
97+
windows = build_plat("windows"),
98+
cygwin = build_plat("cygwin"),
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linux = build_plat("linux"),
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freebsd = build_plat("bsd"),
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openbsd = build_plat("bsd"),
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netbsd = build_plat("bsd"),
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dragonfly = build_plat("bsd")
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}
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}

‎src/lua-cryptorandom.c

Lines changed: 14 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,17 @@
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#define isinf(x) ((x)==(HUGE_VAL)?(1):((x)==(-HUGE_VAL)?(-1):(0)))
3333
#endif
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/*
36+
** helper union to the function
37+
** lua_cryptorandom_take
38+
*/
39+
typedef union tagLuaCryptoRandomInt
40+
{
41+
int value;
42+
unsigned char buffer[sizeof(int)];
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} LuaCryptoRandomInt;
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3546
/*
3647
** helper union to the function
3748
** lua_cryptorandom_integer
@@ -124,18 +135,17 @@ static int lua_cryptorandom_bytes(lua_State *L)
124135

125136
static int lua_cryptorandom_take(lua_State *L)
126137
{
127-
unsigned char buffer[sizeof(int)];
138+
LuaCryptoRandomInt rtake;
128139

129140
unsigned long err;
130-
if (lua_cryptorandom_bytes_impl(L, (unsigned char *)buffer, sizeof(int), &err) == 0)
141+
if (lua_cryptorandom_bytes_impl(L, (unsigned char *)(rtake.buffer), sizeof(int), &err) == 0)
131142
{
132143
lua_pushnil(L);
133144
lua_pushinteger(L, (lua_Integer)err);
134145
}
135146
else
136147
{
137-
int *take_ptr = (int *)buffer;
138-
lua_pushinteger(L, *take_ptr);
148+
lua_pushinteger(L, rtake.value);
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lua_pushnil(L);
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}
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