UTF-8 encoding

Currently, the system only supports UTF-8 encoding. For example, controls such as text boxes can only display UTF-8 encoded strings normally. If you want to display other codes normally, you need to transcode by yourself.

sconv

Sconv is an open source library for transcoding. Here, we use it to convert between utf-8 and gbk.

Preparation

Download sconv source and unzip it to our project jni folder.

UTF-8 to GBK

1. Required header file

   #include <string>
   #include "utf8cover/sconv.h"
   

2. Add function

   string utf8_to_gbk(const char* utf8_str) {
    int size = sconv_utf8_to_unicode(utf8_str, -1, NULL, 0);
    wchar *unicode = new wchar[size / 2 + 1];
    size = sconv_utf8_to_unicode(utf8_str, -1, unicode, size);
    unicode[size / 2] = 0;
   
    size = sconv_unicode_to_gbk(unicode, -1, NULL, 0);
    char *ansi_str = new char[size + 1];
    size = sconv_unicode_to_gbk(unicode, -1, ansi_str, size);
    ansi_str[size] = 0;
   
    string gbk(ansi_str, size);
    delete[] ansi_str;
    delete[] unicode;
    return gbk;
   }
   

3. Use the function just now to perform encoding conversion, an example is as follows:

   const char* utf8_str = "This is utf8 encoding";
   string gbk = utf8_to_gbk(utf8_str);
   LOGD("After conversion, a total of %d bytes", gbk.size());
   for (size_t i = 0; i < gbk.size(); ++i) {
     LOGD("%d byte = %02X", i, gbk.data()[i]);
   }
   

GBK to UTF-8

1. Required header file

   #include <string>
   #include "utf8cover/sconv.h"
   

2. Add function

   string gbk_to_utf8(const char* gbk_str) {
    int size = sconv_gbk_to_unicode(gbk_str, -1, NULL, 0);
    wchar *unicode_str = new wchar[size / 2 + 1];
    size = sconv_gbk_to_unicode(gbk_str, -1, unicode_str, size);
    unicode_str[size / 2] = 0;
   
    size = sconv_unicode_to_utf8(unicode_str, -1, NULL, 0);
    char *utf8_str = new char[size + 1];
    size = sconv_unicode_to_utf8(unicode_str, -1, utf8_str, size);
    utf8_str[size] = 0;
    string utf8(utf8_str, size);
    delete[] unicode_str;
    delete[] utf8_str;
    return utf8;
   }
   

3. Use the function just now to perform encoding conversion, an example is as follows:

   //To testing, here is a gbk encoding array whose content is "This is gbk encoding"
   const char gbk_str[] = {0xd5, 0xe2, 0xca, 0xc7, 0x67, 0x62, 0x6b, 0xb1, 0xe0, 0xc2, 0xeb,0};
   string utf8 = gbk_to_utf8(gbk_str);
   LOGD("After conversion, a total of %d bytes", utf8.size());
   LOGD("Content is：%s", utf8.c_str());