[fpc-pascal] android JNI JString to String
I have a strange problem, I pass data from the android String via JNI. pass data from FreePascal wideString successfully using the following code NewString: function (Env: PJNIEnv; const Unicode: PJChar; Len: JSize): JString; cdecl; GetStringChars:function(Env:PJNIEnv;Str:JString;IsCopy:PJBoolean):PJChar; cdecl; function JNI_WideStringToJString(Env: PJNIEnv; const WStr: WideString): JString; begin Result := Env^.NewString(Env, Pointer(WStr), Length(WStr)); end; but when passing data JString to widestring, using this code : function JNI_JStringToWideString(Env: PJNIEnv; JStr: JString): WideString; var IsCopy: JBoolean; Chars: PJChar; begin if (JStr = nil) then begin Result := ''; Exit; end; Chars := Env^.GetStringChars(Env, JStr, IsCopy); if (Chars = nil) then begin Result := '' end else begin Result := WideString(Chars); Env^.ReleaseStringChars(Env, JStr, Chars); end; end; return only 1 character leading. if anyone has ever experienced ? or there's something wrong with JNI header ? thanks - - -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/android-JNI-JString-to-String-tp4340388p4340388.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
RE : [fpc-pascal] android JNI JString to String
PJChar is defined as a pointer to a word. Casting to WideString isn't working since internally Widestring has extra bytes for reference count and string length. These extra bytes are locate before the actual string. This explains why assigning Pointer(WStr) to PJChar works. Try Result := WideString(PWideChar(Chars)); PWideChar matches probably PJChar and the compiler knows how to convert PWideChar to WideString. Ludo -Message d'origine- De : fpc-pascal-boun...@lists.freepascal.org [mailto:fpc-pascal-boun...@lists.freepascal.org] De la part de herux Envoyé : mardi 26 avril 2011 10:37 À : fpc-pascal@lists.freepascal.org Objet : [fpc-pascal] android JNI JString to String I have a strange problem, I pass data from the android String via JNI. pass data from FreePascal wideString successfully using the following code NewString: function (Env: PJNIEnv; const Unicode: PJChar; Len: JSize): JString; cdecl; GetStringChars:function(Env:PJNIEnv;Str:JString;IsCopy:PJBoolean):PJChar; cdecl; function JNI_WideStringToJString(Env: PJNIEnv; const WStr: WideString): JString; begin Result := Env^.NewString(Env, Pointer(WStr), Length(WStr)); end; but when passing data JString to widestring, using this code : function JNI_JStringToWideString(Env: PJNIEnv; JStr: JString): WideString; var IsCopy: JBoolean; Chars: PJChar; begin if (JStr = nil) then begin Result := ''; Exit; end; Chars := Env^.GetStringChars(Env, JStr, IsCopy); if (Chars = nil) then begin Result := '' end else begin Result := WideString(Chars); Env^.ReleaseStringChars(Env, JStr, Chars); end; end; return only 1 character leading. if anyone has ever experienced ? or there's something wrong with JNI header ? thanks - - -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/android-JNI-JString-to-Stri ng-tp4340388p4340388.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: RE : [fpc-pascal] android JNI JString to String
thanks for the response. I am doing what you suggest. but it's still the same. I debug this line of code using android log Chars := Env^.GetStringChars(Env, AJString, nil); __android_log_write(ANDROID_LOG_DEBUG,'proj_debug',PChar(Chars)); and the log I retrieved : 04-26 17:53:17.942: DEBUG/proj_debug(711): e <--- only "e" character from input AJString = eNp9zt0KwjAMBeBXCecBrApeCEmG+iRzdrX+dKMrMn16Y0G8M5Cr75ATbub7jR4+T3FIgtViiUa5VS5xGPsfrA2c8lG5o5NghrJX7ikInqCzYCo5pgCKgq3NJ1x1+KuvqjEVH3yuXGuc3b4oX2knAO2tfgM6fNHEdbb2jGv1DUfmNOA= so I thought, this is not about that. but I do not know why - - -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/android-JNI-JString-to-String-tp4340388p4340649.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: RE : [fpc-pascal] android JNI JString to String
On 26 Apr 2011, at 13:06, herux wrote: I debug this line of code using android log Chars := Env^.GetStringChars(Env, AJString, nil); __android_log_write(ANDROID_LOG_DEBUG,'proj_debug',PChar(Chars)); and the log I retrieved : 04-26 17:53:17.942: DEBUG/proj_debug(711): e <--- only "e" character That is normal, because Chars is probably an array of jchar, and a jchar is utf-16 (= widechar). That means that if you treat it as pchar and it only contains plain ASCII, the second "ansichar" will always be #0 on a little endian system (on a big endian system, the first "ansichar" will already be #0). Jonas ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
RE : RE : [fpc-pascal] android JNI JString to String
Pchar(Chars) interpretes your widechars as chars. The widechar e is converted to the chars e and #0. The #0 is end of line for a pchar. So your debug output is as expected. Take a look at http://groups.google.com/group/android-ndk/browse_thread/thread/e0ab7aefb398 2c45. It talks about the same problem calling GetStringChars from C. The function returns non null terminated utf16 data. You could also go the hard way, something along the lines of: Chars := Env^.GetStringChars(Env, JStr, @IsCopy); if (Chars = nil) then begin Result := '' end else begin len:=Env^.GetStringLength(Env, JStr); setlength(Result,len); move(Chars,Result[1],len*2); Env^.ReleaseStringChars(Env, JStr, Chars); end; -Message d'origine- De : fpc-pascal-boun...@lists.freepascal.org [mailto:fpc-pascal-boun...@lists.freepascal.org] De la part de herux Envoyé : mardi 26 avril 2011 13:06 À : fpc-pascal@lists.freepascal.org Objet : Re: RE : [fpc-pascal] android JNI JString to String thanks for the response. I am doing what you suggest. but it's still the same. I debug this line of code using android log Chars := Env^.GetStringChars(Env, AJString, nil); __android_log_write(ANDROID_LOG_DEBUG,'proj_debug',PChar(Chars)); and the log I retrieved : 04-26 17:53:17.942: DEBUG/proj_debug(711): e <--- only "e" character from input AJString = eNp9zt0KwjAMBeBXCecBrApeCEmG+iRzdrX+dKMrMn16Y0G8M5Cr75ATbub7jR4+T3FIgtViiUa5 VS5xGPsfrA2c8lG5o5NghrJX7ikInqCzYCo5pgCKgq3NJ1x1+KuvqjEVH3yuXGuc3b4oX2knAO2t fgM6fNHEdbb2jGv1DUfmNOA= so I thought, this is not about that. but I do not know why - - -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/android-JNI-JString-to-Stri ng-tp4340388p4340649.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: RE : RE : [fpc-pascal] android JNI JString to String
Yes, there's bug. thanks you. I using GetStringUTFChars function JNI_JStringToString(Env: PJNIEnv; JStr: jstring): String; var IsCopy: Pjboolean; Chars: PChar; begin if JStr = nil then begin Result := ''; Exit; end; Chars:= Env^.GetStringUTFChars(Env, JStr, IsCopy); if Chars = nil then Result := '' else Begin Result := String(Chars); Env^.ReleaseStringUTFChars(Env, JStr, Chars); end; end; - - -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/android-JNI-JString-to-String-tp4340388p4342883.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
