/*
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include <windows.h>

#include "jni_util.h"
#include "jlong.h"
#include "jdk_internal_jimage_concurrent_ConcurrentPReader.h"

static jfieldID handle_fdID;

JNIEXPORT void JNICALL
Java_jdk_internal_jimage_concurrent_ConcurrentPReader_initIDs(JNIEnv *env, jclass clazz)
{
    CHECK_NULL(clazz = (*env)->FindClass(env, "java/io/FileDescriptor"));
    CHECK_NULL(handle_fdID = (*env)->GetFieldID(env, clazz, "handle", "J"));
}

JNIEXPORT jint JNICALL
Java_jdk_internal_jimage_concurrent_ConcurrentPReader_pread(JNIEnv *env, jclass clazz,
                                                            jobject fdo, jlong address,
                                                            jint len, jlong offset)
{
    OVERLAPPED ov;
    DWORD nread;
    BOOL result;

    jlong handle = (*env)->GetLongField(env, fdo, handle_fdID);
    void *buf = (void *)jlong_to_ptr(address);

    ZeroMemory(&ov, sizeof(ov));
    ov.Offset = (DWORD)offset;
    ov.OffsetHigh = (DWORD)(offset >> 32);

    result = ReadFile(handle, (LPVOID)buf, len, &nread, &ov);
    if (result == 0) {
        JNU_ThrowIOExceptionWithLastError(env, "ReadFile failed");
    }

    return nread;
}