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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@4142 626c5289-ae23-0410-ae9c-e8d60b6d4f22
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Dave Beazley 2002-11-30 22:10:17 +00:00
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Examples/java/typemap/example.i Normal file
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/* File : example.i */
%module example
%{
/*
example of a function that returns a value in the char * argument
normally used like:
char buf[bigenough];
f1(buf);
*/
void f1(char *s) {
if(s != NULL) {
sprintf(s, "hello world");
}
}
void f2(char *s) {
f1(s);
}
void f3(char *s) {
f1(s);
}
%}
/* default behaviour is that of input arg, Java cannot return a value in a
* string argument, so any changes made by f1(char*) will not be seen in the Java
* string passed to the f1 function.
*/
void f1(char *s);
%include various.i
/* use the BYTE argout typemap to get around this. Changes in the string by
* f2 can be seen in Java. */
void f2(char *BYTE);
/* alternative approach uses a StringBuffer typemap for argout */
/* what is the corresponding jni type */
%typemap(jni) char *SBUF "jobject"
/* what types to use in java source code */
%typemap(jtype) char *SBUF "StringBuffer"
%typemap(jstype) char *SBUF "StringBuffer"
/* how to convert java type to requested c type */
%typemap(in) char *SBUF {
jclass sbufClass;
jmethodID toStringID;
jmethodID setLengthID;
jstring js;
$1 = NULL;
if($input != NULL) {
/* get the String from the StringBuffer */
sbufClass = (*jenv)->GetObjectClass(jenv, $input);
toStringID = (*jenv)->GetMethodID(jenv, sbufClass, "toString", "()Ljava/lang/String;");
js = (jstring) (*jenv)->CallObjectMethod(jenv, $input, toStringID);
/* convert the String to a char * */
$1 = (char *)(*jenv)->GetStringUTFChars(jenv, js, 0);
/* zero the original StringBuffer, so we can replace it with the result */
setLengthID = (*jenv)->GetMethodID(jenv, sbufClass, "setLength", "(I)V");
(*jenv)->CallVoidMethod(jenv, $input, setLengthID, (jint) 0);
}
}
/* how to convert the c type to the java type */
%typemap(argout) char *SBUF {
jclass sbufClass;
jmethodID appendStringID;
if($1 != NULL) {
/* append the result to the empty StringBuffer */
sbufClass = (*jenv)->GetObjectClass(jenv, $input);
appendStringID = (*jenv)->GetMethodID(jenv, sbufClass, "append", "(Ljava/lang/String;)Ljava/lang/StringBuffer;");
(*jenv)->CallObjectMethod(jenv, $input, appendStringID, (*jenv)->NewStringUTF(jenv, $1));
if($input != NULL) (*jenv)->ReleaseStringUTFChars(jenv, $input, $1);
}
}
/* Prevent the default freearg typemap from being used */
%typemap(freearg) char *SBUF ""
/* apply the new typemap to our function */
void f3(char *SBUF);