字符集WideCharToMultiByte

GDAL C#封装对中文字符转换过程中存在问题。

C++封装一个Win32 DLL，采用Unicode字符集。使用标准头文件。

https://msdn.microsoft.com/en-us/library/dd319072(VS.85).aspx

 1 class CodePageHelper
 2 {
 3 public:
 4     CodePageHelper(void);
 5     ~CodePageHelper(void);
 6     static wchar_t*  ANSIToUnicode( const char* str );
 7     static char* UnicodeToANSI( const wchar_t* str );
 8     static wchar_t* UTF8ToUnicode( const char* str );
 9     static char* UnicodeToUTF8( const wchar_t* str );
10 };

CodePageHelper.h

  1 #include "StdAfx.h"
  2 #include "CodePageHelper.h"
  3 
  4 
  5 CodePageHelper::CodePageHelper(void)
  6 {
  7 }
  8 
  9 
 10 CodePageHelper::~CodePageHelper(void)
 11 {
 12 }
 13 
 14 // ANSI to Unicode
 15  wchar_t* CodePageHelper:: ANSIToUnicode( const char* str )
 16 {
 17  int  unicodeLen = ::MultiByteToWideChar( CP_ACP,
 18             0,
 19             str,
 20             -1,
 21             NULL,
 22             0 );  
 23  wchar_t *  pUnicode;  
 24  pUnicode = new  wchar_t[unicodeLen+1];  
 25  memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t));  
 26  ::MultiByteToWideChar( CP_ACP,
 27          0,
 28          str,
 29          -1,
 30          (LPWSTR)pUnicode,
 31          unicodeLen );  
 32  wchar_t*  rt;  
 33  rt = ( wchar_t* )pUnicode;
 34  //delete  pUnicode; 
 35  
 36  return  rt;  
 37 }
 38 //  Unicode to ANSI
 39  char* CodePageHelper:: UnicodeToANSI( const wchar_t* str )
 40 {
 41  char*     pElementText;
 42  int    iTextLen;
 43  // wide char to multi char
 44  iTextLen = WideCharToMultiByte( CP_ACP,
 45          0,
 46          str,
 47          -1,
 48          NULL,
 49          0,
 50 NULL,
 51          NULL );
 52  pElementText = new char[iTextLen + 1];
 53  memset( ( void* )pElementText, 0, sizeof( char ) * ( iTextLen + 1 ) );
 54  ::WideCharToMultiByte( CP_ACP,
 55          0,
 56          str,
 57          -1,
 58          pElementText,
 59          iTextLen,
 60          NULL,
 61          NULL );
 62  char* strText;
 63  strText = pElementText;
 64  //delete[] pElementText;
 65  return strText;
 66 }
 67 //  UTF-8 to Unicode
 68  wchar_t* CodePageHelper::UTF8ToUnicode( const char* str )
 69 {
 70  int  unicodeLen = ::MultiByteToWideChar( CP_UTF8,
 71             0,
 72             str,
 73             -1,
 74             NULL,
 75             0 );  
 76  wchar_t *  pUnicode;  
 77  pUnicode = new  wchar_t[unicodeLen+1];  
 78  memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t));  
 79  ::MultiByteToWideChar( CP_UTF8,
 80          0,
 81          str,
 82          -1,
 83          (LPWSTR)pUnicode,
 84          unicodeLen );  
 85  wchar_t*  rt;  
 86  rt = ( wchar_t* )pUnicode;
 87  //delete  pUnicode; 
 88  
 89  return  rt;  
 90 }
 91 //  Unicode to UTF-8    
 92 
 93  char* CodePageHelper::UnicodeToUTF8( const wchar_t* str )
 94 {
 95  char*     pElementText;
 96  int    iTextLen;
 97  // wide char to multi char
 98  iTextLen = WideCharToMultiByte( CP_UTF8,
 99          0,
100          str,
101          -1,
102          NULL,
103          0,
104          NULL,
105          NULL );
106  pElementText = new char[iTextLen + 1];
107  memset( ( void* )pElementText, 0, sizeof( char ) * ( iTextLen + 1 ) );
108  ::WideCharToMultiByte( CP_UTF8,
109          0,
110          str,
111          -1,
112          pElementText,
113          iTextLen,
114          NULL,
115          NULL );
116  char* strText;
117  strText = pElementText;
118  //delete[] pElementText;
119  return strText;
120 }

CodePageHelper

 1 #ifdef DEMIMP_EXPORTS
 2 #define CPL_DLL __declspec(dllexport)
 3 #else
 4 #define CPL_DLL __declspec(dllimport)
 5 #endif
 6 
 7 #ifndef CPL_DISABLE_STDCALL
 8 #  define CPL_STDCALL __stdcall
 9 #endif
10 
11 extern "C"
12 {
13     HANDLE CPL_DLL WINAPI GetMetaData(LPWSTR filepath);
14 };

GDALRaster.h

 1 HANDLE CPL_DLL WINAPI GetMetaData(LPWSTR filepath)
 2 {
 3     //char*  file=CodePageHelper::UnicodeToUTF8((const wchar_t*)filepath);
 4 
 5     char*  file1=CodePageHelper::UnicodeToANSI((const wchar_t*)filepath);
 6     //const wchar_t* file2=filepath;
 7     GDALAllRegister();    
 8     CPLSetConfigOption("GDAL_FILENAME_IS_UTF8","NO");     
 9     GDALDataset *pDSrc = (GDALDataset *)GDALOpen(file1, GA_ReadOnly);    
10     if (pDSrc == NULL)    
11     {    
12         return 0;    
13     }    
14     char** metadata=pDSrc->GetMetadata("");
15     return metadata;
16 }

C# P/Invoke调用：

1  [DllImport("GDALRaster.dll", EntryPoint = "GetMetaData", CharSet = CharSet.Unicode)]
2         private static extern IntPtr CSharp_GetMetadata([In, MarshalAs(UnmanagedType.LPWStr)]string filepath);

解析字符串：

 1 public static string[] GetMetaData(string filePath)
 2         {
 3             IntPtr cPtr = CSharp_GetMetadata(filePath);
 4             if (cPtr == IntPtr.Zero) throw new Exception("打开失败");
 5 
 6             IntPtr objPtr;
 7             int count = 0;
 8             if (cPtr != IntPtr.Zero)
 9             {
10                 while (Marshal.ReadIntPtr(cPtr, count * IntPtr.Size) != IntPtr.Zero)
11                     ++count;
12             }
13             string[] ret = new string[count];
14             if (count > 0)
15             {
16                 for (int cx = 0; cx < count; cx++)
17                 {
18                     objPtr = System.Runtime.InteropServices.Marshal.ReadIntPtr(cPtr, cx * System.Runtime.InteropServices.Marshal.SizeOf(typeof(IntPtr)));
19                     ret[cx] = (objPtr == IntPtr.Zero) ? null : System.Runtime.InteropServices.Marshal.PtrToStringAnsi(objPtr);
20                 }
21             }
22             return ret;
23             //double[] temp = new double[xsize * ysize];
24             //Marshal.Copy(pData, temp, 0, xsize * ysize);
25             //FreeData(pData);
26             //return temp;
27 
28         }