使用zlib压缩解压并导出lua接口

               

网络游戏在前后端交换的过程中，有可能会有大量的数据，比如说游戏回放功能，这时最好是将数据压缩一下。

比较简单的数据压库就是zlib了。

zlib官方文档，常用的函数都在这里了，解释很详细。

一  C++功能实现部分

下面将代码贴上来。

在ZipUtils中添加下面三个函数：

// ZipUtils.h

 <pre name="code" class="cpp">typedef struct{ unsigned str_size; unsigned buf_size; char data[];// 柔性数组}CompressedData;class ZipUtils {    public:  // add by XuLidong  static void testFun();  static unsigned getCompressBound(unsigned len);  static bool compressString(const char* str,CompressedData* pdata);  static bool decompressString(CompressedData* pdata, char* str);};

用到了柔性数组，不动的可以参考我的另一篇文章

下面是相应的实现：

// ZipUtils.cpp

#include <zlib.h>#include <stdlib.h>#include "ZipUtils.h"int test1(){ char text[] = "zlib compress and uncompress test\nxulidong_china@163.com\n2012-11-05\n";   uLong tlen = strlen(text) + 1;  /* 需要把字符串的结束符'\0'也一并处理 */   char* buf = NULL;   uLong blen;   /* 计算缓冲区大小，并为其分配内存 */   blen = compressBound(tlen); /* 压缩后的长度是不会超过blen的 */ printf("compress str_size:%d, buf_size:%d\n", tlen, blen); if((buf = (char*)malloc(sizeof(char) * blen)) == NULL)   {    printf("no enough memory!\n");    return -1;   }   /* 压缩 */   if(compress((Bytef*)buf, &blen, (const Bytef*)text, tlen) != Z_OK)   {    printf("compress failed!\n");    return -1;   }   /* 解压缩 */ printf("uncompress str_size:%d, buf_size:%d\n", tlen, blen); if(uncompress((Bytef*)text, &tlen, (const Bytef*)buf, blen) != Z_OK)   {  printf("uncompress failed!\n");    return -1;   }   /* 打印结果，并释放内存 */   printf("%s", text);   if(buf != NULL)   {    free(buf);    buf = NULL; }}void test2(){ const char* str="abcdefg 中文字符可以吗 ？ 》 , >\ "; unsigned len = strlen(str) + 1; unsigned long blen = compressBound(len); CompressedData* pdata = (CompressedData*)malloc(sizeof(CompressedData) + blen * sizeof(char)); pdata->str_size = len; pdata->buf_size = blen; ZipUtils::compressString(str, pdata); char* ustr = (char*)malloc(len); memset(ustr, 0, len); ZipUtils::decompressString(pdata, ustr); free(ustr);}void ZipUtils::testFun(){ //test1(); test2();}unsigned ZipUtils::getCompressBound(unsigned len){ return (unsigned)compressBound((unsigned long)len);}bool ZipUtils::compressString(const char* str, CompressedData* pdata){  printf("compress string:%s\n", str); int res = compress((Bytef*)pdata->data, (unsigned long*)&(pdata->buf_size), (const Bytef*)str, (unsigned long)pdata->str_size); if( res != Z_OK) {    printf("compress failed, error code:%d\n", res);    return false;   }  printf("string size %d, buffer size: %d\n", pdata->str_size, pdata->buf_size); return true;}bool ZipUtils::decompressString(CompressedData* pdata, char* str){ printf("string size %d, buffer size: %d\n", pdata->str_size, pdata->buf_size); int res = uncompress((Bytef*)str, (unsigned long *)&(pdata->str_size), (const Bytef *)pdata->data, (unsigned long)pdata->buf_size); if(res != Z_OK)   {    printf("uncompress failed, error code:%d\n", res);    return false;   }   printf("uncompress string:%s\n", str); return true;}

二 C++导出到Lua接口

// ZipUtilsLua.h

#include "tolua++.h"#include "tolua_event.h"#include "lauxlib.h"int tolua_ZipUtils_open(lua_State *L);

// ZipUtilsLua.cpp

#include "support/zip_support/ZipUtils.h"#include <string>#include "tolua++.h"#include "tolua_event.h"#include "lauxlib.h"using namespace cocos2d;int TOLUA_API luaCopressString(lua_State *L){  size_t slen = 0; const char *str = lua_tolstring(L, 1, &slen); unsigned blen = ZipUtils::getCompressBound((unsigned long)slen); CompressedData* pdata = (CompressedData*)malloc(sizeof(CompressedData) + blen * sizeof(char)); pdata->str_size = slen; pdata->buf_size = blen; if(ZipUtils::compressString(str, pdata)){  lua_pushlstring(L, (char*)pdata, pdata->buf_size+sizeof(CompressedData));  printf("sizeof=%d", sizeof(CompressedData));   } else{  lua_pushstring(L, ""); } free(pdata); return 1;}int TOLUA_API luaDecopressString(lua_State *L){  const char *strBuf = lua_tostring(L, 1); CompressedData* pdata = (CompressedData*)strBuf; unsigned slen = pdata->str_size; unsigned blen = pdata->buf_size; char* str = (char*)malloc(pdata->str_size * sizeof(char)); if(ZipUtils::decompressString(pdata, str)){  lua_pushlstring(L, str, slen);  } else{  lua_pushstring(L, ""); }  free(str); return 1;}int TOLUA_API luaTestFun(lua_State *L){ ZipUtils::testFun(); return 1;}static luaL_Reg ziplib[] = { {"compress", luaCopressString}, {"decompress", luaDecopressString}, {"testFun", luaTestFun}, {NULL, NULL}};// 函数名必须为luaopen_xxx，其中xxx表示library名称,Lua代码require "xxx"需要与之对应。int luaopen_ZipUtils(lua_State* L){ const char* libName = "ZipUtils"; luaL_register(L, libName, ziplib);// 调用方式libName.函数名 return 1;}int tolua_ZipUtils_open(lua_State *L){  luaopen_ZipUtils(L); return 1;}

注册代码：

    // register lua engine    CCLuaEngine* pEngine = CCLuaEngine::defaultEngine();    CCScriptEngineManager::sharedManager()->setScriptEngine(pEngine);    <span style="font-family: Arial, Helvetica, sans-serif;">tolua_ZipUtils_open</span><span style="font-family: Arial, Helvetica, sans-serif;">(pEngine->getLuaStack()->getLuaState());</span>

三 Lua中调用

 require ("ZipUtils")  local string = "hello, world" local zipData = ZipUtils.compress(string) if c ~= "" then  print("XXXXXXXXXXXXXXXXX compress", zipData) else  print("XXXXXXXXXXXXXXXXX error") end local str = ZipUtils.decompress(zipData) if str ~= "" then  print("XXXXXXXXXXXXXXXXX decompress", str) else  print("XXXXXXXXXXXXXXXXX error") end