From a121cef86fcf7b3f4e3a8f067a68795da14de72c Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Tue, 2 Apr 2019 21:43:25 +0200
Subject: Expose additional libuuid functions

---
 lua_uuid.c             | 92 ++++++++++++++++++++++++++++++++++++++++++++++++--
 test/lua_uuid_test.lua | 25 +++++++++++---
 2 files changed, 110 insertions(+), 7 deletions(-)

diff --git a/lua_uuid.c b/lua_uuid.c
index 94d76b1..60f779c 100644
--- a/lua_uuid.c
+++ b/lua_uuid.c
@@ -4,11 +4,14 @@ Utility for generating UUIDs by wrapping libuuid's generate().
 @license MIT
 @module lua_uuid
 */
+#include <string.h>
 #include <lua.h>
 #include <lauxlib.h>
 #include <uuid/uuid.h>
 
-/// Generate a UUID
+#define UUID_LEN 16
+
+/// Generate a UUID. As a shortcut, you can also call the module directly to generate a uuid.
 // @return uuid_str
 // @function generate()
 static int generate(lua_State *L) {
@@ -22,7 +25,92 @@ static int generate(lua_State *L) {
     return 1;
 }
 
+/// Generate a binary UUID
+// @return uuid
+// @function generate_binary()
+static int generate_binary(lua_State *L) {
+    uuid_t uuid;
+    uuid_generate(uuid);
+
+    lua_pushlstring(L, (char *)&uuid, UUID_LEN);
+    return 1;
+}
+
+/// Unparse UUID (create a hex string representation from a binary string representation)
+// @tparam string binary_uuid
+// @treturn string uuid_str
+// @error if the binary_uuid could not be unparsed
+// @function unparse
+static int unparse(lua_State *L) {
+    const char *binary_uuid;
+    size_t binary_uuid_len;
+    uuid_t uuid;
+    char uuid_str[37];
+
+    binary_uuid = luaL_checklstring(L, 1, &binary_uuid_len);
+
+    if (binary_uuid_len != UUID_LEN) {
+        lua_pushnil(L);
+        lua_pushfstring(L, "could not unparse uuid: string length was != %d", UUID_LEN);
+        return 2;
+    }
+
+    memcpy(&uuid[0], binary_uuid, UUID_LEN);
+
+    uuid_unparse_lower(uuid, uuid_str);
+
+    lua_pushstring(L, uuid_str);
+    return 1;
+}
+
+/// Parse a hexadecimal UUID into a binary representation
+// @tparam string uuid_str
+// @treturn string uuid
+// @error if the uuid_str could not be parsed
+// @function parse
+static int parse(lua_State *L) {
+    const char *uuid_str;
+    uuid_t uuid;
+
+    uuid_str = luaL_checkstring(L, 1);
+
+    if (uuid_parse(uuid_str, uuid) != 0) {
+        lua_pushnil(L);
+        lua_pushstring(L, "could not parse uuid");
+        return 2;
+    }
+
+    lua_pushlstring(L, (char *)uuid, UUID_LEN);
+    return 1;
+}
+
+static int mt_call(lua_State *L) {
+    lua_pop(L, 1);
+    return generate(L);
+}
+
+static const struct luaL_Reg mylib [] = {
+    {"generate", generate},
+    {"generate_binary", generate_binary},
+    {"unparse", unparse},
+    {"parse", parse},
+    {NULL, NULL}
+};
+
 int luaopen_lua_uuid(lua_State *L) {
-    lua_pushcfunction(L, generate);
+    // Set up library table
+    lua_newtable(L);
+    const luaL_Reg *fundef = mylib;
+    for(fundef = mylib; fundef->name != NULL; fundef++) {
+        lua_pushcfunction(L, fundef->func);
+        lua_setfield(L, -2, fundef->name);
+    }
+
+    // Set up metatable
+    lua_newtable(L);
+    lua_pushcfunction(L, mt_call);
+    lua_setfield(L, -2, "__call");
+
+    lua_setmetatable(L, -2);
     return 1;
 }
diff --git a/test/lua_uuid_test.lua b/test/lua_uuid_test.lua
index 19ebf67..3406d56 100755
--- a/test/lua_uuid_test.lua
+++ b/test/lua_uuid_test.lua
@@ -2,10 +2,25 @@ package.path = package.path..";./?.lua"
 
 local uuid = require "lua_uuid"
 
-assert(type(uuid) == "function")
+assert(type(uuid) == "table")
 
-local first = uuid()
-local second = uuid()
+local function test_generator(gen)
+  local first = gen()
+  local second = gen()
 
-assert(first ~= second)
-assert(type(uuid()) == "string")
+  assert(first ~= second)
+  assert(type(gen()) == "string")
+end
+
+test_generator(uuid)
+test_generator(uuid.generate)
+test_generator(uuid.generate_binary)
+
+local hexuuid = "cf08a9b2-3492-4b71-9bd9-eb12d9f463a6"
+local binuuid = "\207\008\169\178\052\146\075\113\155\217\235\018\217\244\099\166"
+
+assert(assert(uuid.parse(hexuuid)) == binuuid)
+assert(assert(uuid.unparse(binuuid)) == hexuuid)
+
+assert(uuid.parse("foobar") == nil)
+assert(uuid.unparse("foobar") == nil)
-- 
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