iconv编码转换

环境：cocos2dx 3.10

1.vs环境下编译windows版本，需要增加头文件和链接库
①cocos2d-x-3.10\external\win32-specific\icon\include
②cocos2d-x-3.10\external\win32-specific\icon\prebuilt

2.编译android版本，需要修改Android.mk文件增加iconv支持
①LOCAL_WHOLE_STATIC_LIBRARIES += android_support
②$(call import-module, android/support)

3.转换函数

 #if CC_TARGET_PLATFORM == CC_PLATFORM_WIN32
 #include "iconv.h"
 #elif CC_TARGET_PLATFORM == CC_PLATFORM_IOS
 #include <iconv.h>
 #elif CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
 #include "iconv.h"
 #endif

 int iconv_convert(void *src, unsigned int src_len, const char *src_charset, void *dest, unsigned int dest_len, const char *dest_charset)
 {
     int ret = -;
     iconv_t oConv = iconv_open(dest_charset, src_charset);
     if (oConv == (iconv_t)(-))
     {
         cocos2d::log("ERROR: unable to open libiconv.");
         return ret;
     }

 #ifdef _WIN32
     const char *in = (const char *)src;
 #else
     char *in = (char *)src;
 #endif
     char *out = (char *)dest;
     size_t src_left = src_len, dest_left = dest_len;

     //dest_len目标长度不够的话，会进入这里
     //in_left表示还有多少长度输入没有转换，out_left表示还有长度输出剩余
     if (iconv(oConv, &in, &src_left, &out, &dest_left) != (size_t)(-)){
         //返回转换了多少空间，用来计算剩余多少空间（可以用于确定写入\0的位置；但是如果src中已经包含了\0则无需再写入）
         ret = dest_len - dest_left;
     }

     iconv_close(oConv);

     return ret;
 }

 /*
 //使用例子
 char inStr[] = "China中国 Test";
 char outStr[1024] = {};
 if (iconv_convert(&inStr, sizeof(inStr), "GBK", &outStr, sizeof(outStr), "UTF-8") > 0){
 Label* label1 = Label::createWithSystemFont(outStr, "fonts/arial.ttf", 24);
 }
 */