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// Copyright 2020 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
// This file provides a Java Native Interface (JNI) version of the Detokenizer
// class. This facilitates using the tokenizer library from Java or other JVM
// languages. A corresponding Java class is provided in Detokenizer.java.
#include <jni.h>
#include <cstring>
#include "pw_preprocessor/concat.h"
#include "pw_span/span.h"
#include "pw_tokenizer/detokenize.h"
#include "pw_tokenizer/token_database.h"
#define DETOKENIZER_METHOD(method) \
JNICALL PW_CONCAT(Java_dev_pigweed_tokenizer_, Detokenizer_, method)
namespace pw::tokenizer {
namespace {
Detokenizer* HandleToPointer(jlong handle) {
Detokenizer* detokenizer = nullptr;
std::memcpy(&detokenizer, &handle, sizeof(detokenizer));
static_assert(sizeof(detokenizer) <= sizeof(handle));
return detokenizer;
}
jlong PointerToHandle(Detokenizer* detokenizer) {
jlong handle = 0;
std::memcpy(&handle, &detokenizer, sizeof(detokenizer));
static_assert(sizeof(handle) >= sizeof(detokenizer));
return handle;
}
} // namespace
extern "C" {
static_assert(sizeof(jbyte) == 1u);
JNIEXPORT jlong DETOKENIZER_METHOD(newNativeDetokenizer)(JNIEnv* env,
jclass,
jbyteArray array) {
jbyte* const data = env->GetByteArrayElements(array, nullptr);
const jsize size = env->GetArrayLength(array);
TokenDatabase tokens = TokenDatabase::Create(pw::span(data, size));
const jlong handle =
PointerToHandle(new Detokenizer(tokens.ok() ? tokens : TokenDatabase()));
env->ReleaseByteArrayElements(array, data, 0);
return handle;
}
JNIEXPORT void DETOKENIZER_METHOD(deleteNativeDetokenizer)(JNIEnv*,
jclass,
jlong handle) {
delete HandleToPointer(handle);
}
JNIEXPORT jstring DETOKENIZER_METHOD(detokenizeNative)(JNIEnv* env,
jobject,
jlong handle,
jbyteArray array) {
jbyte* const data = env->GetByteArrayElements(array, nullptr);
const jsize size = env->GetArrayLength(array);
DetokenizedString result = HandleToPointer(handle)->Detokenize(data, size);
env->ReleaseByteArrayElements(array, data, 0);
return result.matches().empty()
? nullptr
: env->NewStringUTF(result.BestString().c_str());
}
} // extern "C"
} // namespace pw::tokenizer