SWIG unsigned char and byte[]

问题

I've looked all over the place. I have tried some of the techniques on this site. To no avail.

I have a c++ global function

char* squid( char* buff, int len );

I create a .i file

%module Crabby

%include "arrays_java.i"

%{
/* headers here are included in the wrapper code */
#include "sponge.h"
%}



%typemap(jtype) (const signed char *arr, size_t sz) "byte[]"
%typemap(jstype) (const signed char *arr, size_t sz) "byte[]"
%typemap(jni) (const signed char *arr, size_t sz) "jbyteArray"
%typemap(javain) (const signed char *arr, size_t sz) "$javainput"

%typemap(in) (const signed char* arr, size_t sz) {
  $1 = JCALL2(GetByteArrayElements, jenv, $input, NULL);
  const size_t sz = JCALL1(GetArrayLength, jenv, $input);
  $2 = $1 + sz;
}

%typemap(freearg) (const signed char *arr, size_t sz) {
  // Or use  0 instead of ABORT to keep changes if it was a copy
  JCALL3(ReleaseByteArrayElements, jenv, $input, $1, JNI_ABORT); 
}

%apply (const signed char* arr, size_t sz) { (const unsigned char* buff, int len) }
%apply (const signed char* arr, size_t sz) { (const unsigned char* query, int queryLen) }

%include "sponge.h"

No matter what I do the interface is always

public static String Squid(String buff, int len)

if I remove the unsigned I get illegal conversions in the cxx wrapper

this is Swig 2.0.1

回答1:

Your interface is close, but has the following issues:

const matters for %apply
You need to exactly match the signed/unsigned qualifier for buff (there is no qualifier in the declaration you showed.
Your in typemap needs numinputs=1 to compress it to just one Java input.
Setting the size to be a computed pointer doesn't make much sense.

So the fixed interface looks like:

%module Crabby

%include "arrays_java.i"

%{
/* headers here are included in the wrapper code */
#include "sponge.h"
%}

%typemap(jtype) (const signed char *arr, size_t sz) "byte[]"
%typemap(jstype) (const signed char *arr, size_t sz) "byte[]"
%typemap(jni) (const signed char *arr, size_t sz) "jbyteArray"
%typemap(javain) (const signed char *arr, size_t sz) "$javainput"

%typemap(in,numinputs=1) (const signed char* arr, size_t sz) {
  $1 = JCALL2(GetByteArrayElements, jenv, $input, NULL);
  const size_t sz = JCALL1(GetArrayLength, jenv, $input);
  $2 = sz;
}

%typemap(freearg) (const signed char *arr, size_t sz) {
  // Or use  0 instead of ABORT to keep changes if it was a copy
  JCALL3(ReleaseByteArrayElements, jenv, $input, $1, JNI_ABORT);
}

%apply (const signed char* arr, size_t sz) { ( char* buff, int len) }

%include "sponge.h"

来源：https://stackoverflow.com/questions/16673256/swig-unsigned-char-and-byte

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