From 9feaf15b3d982259236bab27c481d4720f0f23b8 Mon Sep 17 00:00:00 2001
From: Cloud Wu <cloudwu@gmail.com>
Date: Mon, 14 Jul 2014 14:14:05 +0800
Subject: [PATCH] add netpack.pack_padding

---
 examples/login/msggate.lua |  2 +-
 lualib-src/lua-netpack.c   | 43 +++++++++++++++++++++++++++++++-------
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/examples/login/msggate.lua b/examples/login/msggate.lua
index a7315f4f..32b3518f 100644
--- a/examples/login/msggate.lua
+++ b/examples/login/msggate.lua
@@ -32,7 +32,7 @@ function handler.connect(fd, addr)
 end
 
 local function auth(fd, msg, sz)
---	base64(base64(uid)@base64(server)#base64(subid):index:request:base64(hmac)
+--	base64(uid)@base64(server)#base64(subid):index:request:base64(hmac)
 	local message = netpack.tostring(msg, sz)
 	local username, index, request , hmac = string.match(message, "([^:]*):([^:]*):([^:]*):([^:]*)")
 	local content = users[username]
diff --git a/lualib-src/lua-netpack.c b/lualib-src/lua-netpack.c
index a95ed4d7..432818e7 100644
--- a/lualib-src/lua-netpack.c
+++ b/lualib-src/lua-netpack.c
@@ -393,13 +393,13 @@ lpop(lua_State *L) {
  */
 
 static const char *
-tolstring(lua_State *L, size_t *sz) {
+tolstring(lua_State *L, size_t *sz, int index) {
 	const char * ptr;
-	if (lua_isuserdata(L,1)) {
-		ptr = (const char *)lua_touserdata(L,1);
-		*sz = (size_t)luaL_checkinteger(L, 2);
+	if (lua_isuserdata(L,index)) {
+		ptr = (const char *)lua_touserdata(L,index);
+		*sz = (size_t)luaL_checkinteger(L, index+1);
 	} else {
-		ptr = luaL_checklstring(L, 1, sz);
+		ptr = luaL_checklstring(L, index, sz);
 	}
 	return ptr;
 }
@@ -413,7 +413,7 @@ write_size(uint8_t * buffer, int len) {
 static int
 lpack(lua_State *L) {
 	size_t len;
-	const char * ptr = tolstring(L, &len);
+	const char * ptr = tolstring(L, &len, 1);
 	if (len > 0x10000) {
 		return luaL_error(L, "Invalid size (too long) of data : %d", (int)len);
 	}
@@ -433,7 +433,7 @@ lpack_string(lua_State *L) {
 	uint8_t tmp[SMALLSTRING+2];
 	size_t len;
 	uint8_t *buffer;
-	const char * ptr = tolstring(L, &len);
+	const char * ptr = tolstring(L, &len, 1);
 	if (len > 0x10000) {
 		return luaL_error(L, "Invalid size (too long) of data : %d", (int)len);
 	}
@@ -451,6 +451,34 @@ lpack_string(lua_State *L) {
 	return 1;
 }
 
+static int
+lpack_padding(lua_State *L) {
+	uint8_t tmp[SMALLSTRING+2];
+	size_t content_sz;
+	uint8_t *buffer;
+	const char * ptr = tolstring(L, &content_sz, 2);
+	size_t header_sz = 0;
+	const char * header = luaL_checklstring(L,1,&header_sz);
+	size_t len = header_sz + content_sz;
+
+	if (len > 0x10000) {
+		return luaL_error(L, "Invalid size (too long) of data : %d", (int)len);
+	}
+
+	if (len <= SMALLSTRING) {
+		buffer = tmp;
+	} else {
+		buffer = lua_newuserdata(L, len + 2);
+	}
+
+	write_size(buffer, len);
+	memcpy(buffer+2, header, header_sz);
+	memcpy(buffer+2+header_sz, ptr, content_sz);
+	lua_pushlstring(L, (const char *)buffer, len+2);
+
+	return 1;
+}
+
 static int
 ltostring(lua_State *L) {
 	void * ptr = lua_touserdata(L, 1);
@@ -471,6 +499,7 @@ luaopen_netpack(lua_State *L) {
 		{ "pop", lpop },
 		{ "pack", lpack },
 		{ "pack_string", lpack_string },
+		{ "pack_padding", lpack_padding },
 		{ "clear", lclear },
 		{ "tostring", ltostring },
 		{ NULL, NULL },