/*
 *  FreeLoader
 *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
 *  Copyright (C) 2009       Hervé Poussineau  <hpoussin@reactos.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _M_ARM
#include <freeldr.h>
#include <debug.h>

#define SECTORSIZE 2048
#define TAG_ISO_BUFFER 'BosI'
#define TAG_ISO_FILE 'FosI'

DBG_DEFAULT_CHANNEL(FILESYSTEM);

static BOOLEAN IsoSearchDirectoryBufferForFile(PVOID DirectoryBuffer, ULONG DirectoryLength, PCHAR FileName, PISO_FILE_INFO IsoFileInfoPointer)
{
    PDIR_RECORD    Record;
    ULONG        Offset;
    ULONG i;
    CHAR Name[32];

    TRACE("IsoSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x DirectoryLength = %d FileName = %s\n", DirectoryBuffer, DirectoryLength, FileName);

    RtlZeroMemory(Name, 32 * sizeof(UCHAR));

    Offset = 0;
    Record = (PDIR_RECORD)DirectoryBuffer;
    while (TRUE)
    {
        Offset = Offset + Record->RecordLength;
        Record = (PDIR_RECORD)((ULONG_PTR)DirectoryBuffer + Offset);

        if (Record->RecordLength == 0)
        {
            Offset = ROUND_UP(Offset, SECTORSIZE);
            Record = (PDIR_RECORD)((ULONG_PTR)DirectoryBuffer + Offset);
        }

        if (Offset >= DirectoryLength)
            return FALSE;

        if (Record->FileIdLength == 1 && Record->FileId[0] == 0)
        {
            TRACE("Name '.'\n");
        }
        else if (Record->FileIdLength == 1 && Record->FileId[0] == 1)
        {
            TRACE("Name '..'\n");
        }
        else
        {
            for (i = 0; i < Record->FileIdLength && Record->FileId[i] != ';'; i++)
                Name[i] = Record->FileId[i];
            Name[i] = 0;
            TRACE("Name '%s'\n", Name);

            if (strlen(FileName) == strlen(Name) && _stricmp(FileName, Name) == 0)
            {
                IsoFileInfoPointer->FileStart = Record->ExtentLocationL;
                IsoFileInfoPointer->FileSize = Record->DataLengthL;
                IsoFileInfoPointer->FilePointer = 0;
                IsoFileInfoPointer->Directory = (Record->FileFlags & 0x02)?TRUE:FALSE;

                return TRUE;
            }

        }

        RtlZeroMemory(Name, 32 * sizeof(UCHAR));
    }

    return FALSE;
}


/*
 * IsoBufferDirectory()
 * This function allocates a buffer, reads the specified directory
 * and returns a pointer to that buffer into pDirectoryBuffer. The
 * function returns an ARC error code. The directory is specified
 * by its starting sector and length.
 */
static ARC_STATUS IsoBufferDirectory(ULONG DeviceId, ULONG DirectoryStartSector, ULONG DirectoryLength,
    PVOID* pDirectoryBuffer)
{
    PVOID DirectoryBuffer;
    ULONG SectorCount;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    TRACE("IsoBufferDirectory() DirectoryStartSector = %d DirectoryLength = %d\n", DirectoryStartSector, DirectoryLength);

    SectorCount = ROUND_UP(DirectoryLength, SECTORSIZE) / SECTORSIZE;
    TRACE("Trying to read (DirectoryCount) %d sectors.\n", SectorCount);

    //
    // Attempt to allocate memory for directory buffer
    //
    TRACE("Trying to allocate (DirectoryLength) %d bytes.\n", DirectoryLength);
    DirectoryBuffer = FrLdrTempAlloc(DirectoryLength, TAG_ISO_BUFFER);
    if (!DirectoryBuffer)
        return ENOMEM;

    //
    // Now read directory contents into DirectoryBuffer
    //
    Position.HighPart = 0;
    Position.LowPart = DirectoryStartSector * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
    {
        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
        return Status;
    }
    Status = ArcRead(DeviceId, DirectoryBuffer, SectorCount * SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count != SectorCount * SECTORSIZE)
    {
        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
        return EIO;
    }

    *pDirectoryBuffer = DirectoryBuffer;
    return ESUCCESS;
}


/*
 * IsoLookupFile()
 * This function searches the file system for the
 * specified filename and fills in an ISO_FILE_INFO structure
 * with info describing the file, etc. returns ARC error code
 */
static ARC_STATUS IsoLookupFile(PCSTR FileName, ULONG DeviceId, PISO_FILE_INFO IsoFileInfoPointer)
{
    UCHAR Buffer[SECTORSIZE];
    PPVD Pvd = (PPVD)Buffer;
    UINT32        i;
    ULONG            NumberOfPathParts;
    CHAR        PathPart[261];
    PVOID        DirectoryBuffer;
    ULONG        DirectorySector;
    ULONG        DirectoryLength;
    ISO_FILE_INFO    IsoFileInfo;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    TRACE("IsoLookupFile() FileName = %s\n", FileName);

    RtlZeroMemory(IsoFileInfoPointer, sizeof(ISO_FILE_INFO));
    RtlZeroMemory(&IsoFileInfo, sizeof(ISO_FILE_INFO));

    //
    // Read The Primary Volume Descriptor
    //
    Position.HighPart = 0;
    Position.LowPart = 16 * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
        return Status;
    Status = ArcRead(DeviceId, Pvd, SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count < sizeof(PVD))
        return EIO;

    DirectorySector = Pvd->RootDirRecord.ExtentLocationL;
    DirectoryLength = Pvd->RootDirRecord.DataLengthL;

    //
    // Figure out how many sub-directories we are nested in
    //
    NumberOfPathParts = FsGetNumPathParts(FileName);

    //
    // Loop once for each part
    //
    for (i=0; i<NumberOfPathParts; i++)
    {
        //
        // Get first path part
        //
        FsGetFirstNameFromPath(PathPart, FileName);

        //
        // Advance to the next part of the path
        //
        for (; (*FileName != '\\') && (*FileName != '/') && (*FileName != '\0'); FileName++)
        {
        }
        FileName++;

        //
        // Buffer the directory contents
        //
        Status = IsoBufferDirectory(DeviceId, DirectorySector, DirectoryLength, &DirectoryBuffer);
        if (Status != ESUCCESS)
            return Status;

        //
        // Search for file name in directory
        //
        if (!IsoSearchDirectoryBufferForFile(DirectoryBuffer, DirectoryLength, PathPart, &IsoFileInfo))
        {
            FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
            return ENOENT;
        }

        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);

        //
        // If we have another sub-directory to go then
        // grab the start sector and file size
        //
        if ((i+1) < NumberOfPathParts)
        {
            DirectorySector = IsoFileInfo.FileStart;
            DirectoryLength = IsoFileInfo.FileSize;
        }

    }

    RtlCopyMemory(IsoFileInfoPointer, &IsoFileInfo, sizeof(ISO_FILE_INFO));

    return ESUCCESS;
}

ARC_STATUS IsoClose(ULONG FileId)
{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);

    FrLdrTempFree(FileHandle, TAG_ISO_FILE);

    return ESUCCESS;
}

ARC_STATUS IsoGetFileInformation(ULONG FileId, FILEINFORMATION* Information)
{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);

    TRACE("IsoGetFileInformation() FileSize = %d\n", FileHandle->FileSize);
    TRACE("IsoGetFileInformation() FilePointer = %d\n", FileHandle->FilePointer);

    RtlZeroMemory(Information, sizeof(FILEINFORMATION));
    Information->EndingAddress.LowPart = FileHandle->FileSize;
    Information->CurrentAddress.LowPart = FileHandle->FilePointer;

    return ESUCCESS;
}

ARC_STATUS IsoOpen(CHAR* Path, OPENMODE OpenMode, ULONG* FileId)
{
    ISO_FILE_INFO TempFileInfo;
    PISO_FILE_INFO FileHandle;
    ULONG DeviceId;
    ARC_STATUS Status;

    if (OpenMode != OpenReadOnly)
        return EACCES;

    DeviceId = FsGetDeviceId(*FileId);

    TRACE("IsoOpen() FileName = %s\n", Path);

    RtlZeroMemory(&TempFileInfo, sizeof(TempFileInfo));
    Status = IsoLookupFile(Path, DeviceId, &TempFileInfo);
    if (Status != ESUCCESS)
        return ENOENT;

    FileHandle = FrLdrTempAlloc(sizeof(ISO_FILE_INFO), TAG_ISO_FILE);
    if (!FileHandle)
        return ENOMEM;

    RtlCopyMemory(FileHandle, &TempFileInfo, sizeof(ISO_FILE_INFO));

    FsSetDeviceSpecific(*FileId, FileHandle);
    return ESUCCESS;
}

ARC_STATUS IsoRead(ULONG FileId, VOID* Buffer, ULONG N, ULONG* Count)
{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    UCHAR SectorBuffer[SECTORSIZE];
    LARGE_INTEGER Position;
    ULONG DeviceId;
    ULONG FilePointer;
    ULONG        SectorNumber;
    ULONG        OffsetInSector;
    ULONG        LengthInSector;
    ULONG        NumberOfSectors;
    ULONG BytesRead;
    ARC_STATUS Status;

    TRACE("IsoRead() Buffer = %p, N = %lu\n", Buffer, N);

    DeviceId = FsGetDeviceId(FileId);
    *Count = 0;

    //
    // If they are trying to read past the
    // end of the file then return success
    // with Count == 0
    //
    FilePointer = FileHandle->FilePointer;
    if (FilePointer >= FileHandle->FileSize)
    {
        return ESUCCESS;
    }

    //
    // If they are trying to read more than there is to read
    // then adjust the amount to read
    //
    if (FilePointer + N > FileHandle->FileSize)
    {
        N = FileHandle->FileSize - FilePointer;
    }

    //
    // Ok, now we have to perform at most 3 calculations
    // I'll draw you a picture (using nifty ASCII art):
    //
    // CurrentFilePointer -+
    //                     |
    //    +----------------+
    //    |
    // +-----------+-----------+-----------+-----------+
    // | Sector  1 | Sector  2 | Sector  3 | Sector  4 |
    // +-----------+-----------+-----------+-----------+
    //    |                                    |
    //    +---------------+--------------------+
    //                    |
    // N -----------------+
    //
    // 1 - The first calculation (and read) will align
    //     the file pointer with the next sector
    //     boundary (if we are supposed to read that much)
    // 2 - The next calculation (and read) will read
    //     in all the full sectors that the requested
    //     amount of data would cover (in this case
    //     sectors 2 & 3).
    // 3 - The last calculation (and read) would read
    //     in the remainder of the data requested out of
    //     the last sector.
    //


    //
    // Only do the first read if we
    // aren't aligned on a cluster boundary
    //
    if (FilePointer % SECTORSIZE)
    {
        //
        // Do the math for our first read
        //
        SectorNumber = FileHandle->FileStart + (FilePointer / SECTORSIZE);
        OffsetInSector = FilePointer % SECTORSIZE;
        LengthInSector = (N > (SECTORSIZE - OffsetInSector)) ? (SECTORSIZE - OffsetInSector) : N;

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, SectorBuffer, SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != SECTORSIZE)
        {
            return EIO;
        }
        RtlCopyMemory(Buffer, SectorBuffer + OffsetInSector, LengthInSector);
        *Count += LengthInSector;
        N -= LengthInSector;
        FilePointer += LengthInSector;
        Buffer = (PVOID)((ULONG_PTR)Buffer + LengthInSector);
    }

    //
    // Do the math for our second read (if any data left)
    //
    if (N > 0)
    {
        //
        // Determine how many full clusters we need to read
        //
        NumberOfSectors = (N / SECTORSIZE);

        SectorNumber = FileHandle->FileStart + (FilePointer / SECTORSIZE);

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, Buffer, NumberOfSectors * SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != NumberOfSectors * SECTORSIZE)
        {
            return EIO;
        }

        *Count += NumberOfSectors * SECTORSIZE;
        N -= NumberOfSectors * SECTORSIZE;
        FilePointer += NumberOfSectors * SECTORSIZE;
        Buffer = (PVOID)((ULONG_PTR)Buffer + NumberOfSectors * SECTORSIZE);
    }

    //
    // Do the math for our third read (if any data left)
    //
    if (N > 0)
    {
        SectorNumber = FileHandle->FileStart + (FilePointer / SECTORSIZE);

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, SectorBuffer, SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != SECTORSIZE)
        {
            return EIO;
        }
        RtlCopyMemory(Buffer, SectorBuffer, N);
        *Count += N;
        FilePointer += N;
    }

    TRACE("IsoRead() done\n");

    return ESUCCESS;
}

ARC_STATUS IsoSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMode)
{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);

    TRACE("IsoSeek() NewFilePointer = %lu\n", Position->LowPart);

    if (SeekMode != SeekAbsolute)
        return EINVAL;
    if (Position->HighPart != 0)
        return EINVAL;
    if (Position->LowPart >= FileHandle->FileSize)
        return EINVAL;

    FileHandle->FilePointer = Position->LowPart;
    return ESUCCESS;
}

const DEVVTBL Iso9660FuncTable =
{
    IsoClose,
    IsoGetFileInformation,
    IsoOpen,
    IsoRead,
    IsoSeek,
    L"cdfs",
};

const DEVVTBL* IsoMount(ULONG DeviceId)
{
    UCHAR Buffer[SECTORSIZE];
    PPVD Pvd = (PPVD)Buffer;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    //
    // Read The Primary Volume Descriptor
    //
    Position.HighPart = 0;
    Position.LowPart = 16 * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
        return NULL;
    Status = ArcRead(DeviceId, Pvd, SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count < sizeof(PVD))
        return NULL;

    //
    // Check if PVD is valid. If yes, return ISO9660 function table
    //
    if (Pvd->VdType == 1 && RtlEqualMemory(Pvd->StandardId, "CD001", 5))
        return &Iso9660FuncTable;
    else
        return NULL;
}

#endif

