/*

 * Copyright (c) 2015, 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 <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <io.h>

#include <malloc.h>

#include "jni.h"

#include "osSupport.hpp"

/**

 * Open a regular file read-only.

 * Return the file descriptor.

 */

jint osSupport::openReadOnly(const char *path) {

    return ::open(path, 0, 0);

}

/**

 * Close a file descriptor.

 */

jint osSupport::close(jint fd) {

    return ::close(fd);

}

/**

 * Return the size of a regular file.

 */

jlong osSupport::size(const char *path) {

    struct stat statbuf;

    if (stat(path, &statbuf) < 0 ||

            (statbuf.st_mode & S_IFREG) != S_IFREG) {

        return -1;

    }

    return (jlong) statbuf.st_size;

}

/**

 * Read nBytes at offset into a buffer.

 */

jlong osSupport::read(jint fd, char *buf, jlong nBytes, jlong offset) {

    OVERLAPPED ov;

    DWORD nread;

    BOOL result;

    ZeroMemory(&ov, sizeof (ov));

    ov.Offset = (DWORD) offset;

    ov.OffsetHigh = (DWORD) (offset >> 32);

    HANDLE h = (HANDLE)::_get_osfhandle(fd);

    result = ReadFile(h, (LPVOID) buf, (DWORD) nBytes, &nread, &ov);

    return result ? nread : 0;

}

/**

 * Map nBytes at offset into memory and return the address.

 * The system chooses the address.

 */

void* osSupport::map_memory(jint fd, const char *file_name, size_t file_offset, size_t bytes) {

    HANDLE hFile;

    char* base = NULL;

    // Get a handle to the file

    hFile = CreateFile(file_name, GENERIC_READ, FILE_SHARE_READ, NULL,

            OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    if (hFile != NULL) {

        // Create a file mapping handle

        HANDLE hMap = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0,

                NULL /* file_name */);

        if (hMap != NULL) {

            // Map the file into the address space at the offset

            base = (char*) MapViewOfFileEx(hMap, FILE_MAP_READ, 0, (DWORD) file_offset,

                    (DWORD) bytes, NULL);

            CloseHandle(hMap); // The mapping is no longer needed

        }

        CloseHandle(hFile); // The file handle is no longer needed

    }

    return base;

}

/**

 * Unmap nBytes of memory at address.

 */

int osSupport::unmap_memory(void* addr, size_t bytes) {

    BOOL result = UnmapViewOfFile(addr);

    return result;

}

/**

 * A CriticalSection to protect a small section of code.

 */

void SimpleCriticalSection::enter() {

    EnterCriticalSection(&critical_section);

}

void SimpleCriticalSection::exit() {

    LeaveCriticalSection(&critical_section);

}

SimpleCriticalSection::SimpleCriticalSection() {

    InitializeCriticalSection(&critical_section);

}

//SimpleCriticalSection::~SimpleCriticalSection() {

//    DeleteCriticalSection(&critical_section);

//}