SFileOpenFileEx.cpp

/*****************************************************************************/
/* SFileOpenFileEx.cpp                    Copyright (c) Ladislav Zezula 2003 */
/*---------------------------------------------------------------------------*/
/* Description :                                                             */
/*---------------------------------------------------------------------------*/
/*   Date    Ver   Who  Comment                                              */
/* --------  ----  ---  -------                                              */
/* xx.xx.99  1.00  Lad  The first version of SFileOpenFileEx.cpp             */
/*****************************************************************************/

#define __STORMLIB_SELF__
#include "StormLib.h"
#include "StormCommon.h"

/*****************************************************************************/
/* Local functions                                                           */
/*****************************************************************************/

static DWORD FindHashIndex(TMPQArchive * ha, DWORD dwFileIndex)
{
    TMPQHash * pHashTableEnd;
    TMPQHash * pHash;
    DWORD dwFirstIndex = HASH_ENTRY_FREE;

    // Should only be called if the archive has hash table
    assert(ha->pHashTable != NULL);

    // Multiple hash table entries can point to the file table entry.
    // We need to search all of them
    pHashTableEnd = ha->pHashTable + ha->pHeader->dwHashTableSize;
    for(pHash = ha->pHashTable; pHash < pHashTableEnd; pHash++)
    {
        if(MPQ_BLOCK_INDEX(pHash) == dwFileIndex)
        {
            // Duplicate hash entry found
            if(dwFirstIndex != HASH_ENTRY_FREE)
                return HASH_ENTRY_FREE;
            dwFirstIndex = (DWORD)(pHash - ha->pHashTable);
        }
    }

    // Return the hash table entry index
    return dwFirstIndex;
}

static const char * GetPatchFileName(TMPQArchive * ha, const char * szFileName, char * szBuffer)
{
    TMPQNamePrefix * pPrefix;

    // Are there patches in the current MPQ?
    if(ha->dwFlags & MPQ_FLAG_PATCH)
    {
        // The patch prefix must be already known here
        assert(ha->pPatchPrefix != NULL);
        pPrefix = ha->pPatchPrefix;

        // The patch name for "OldWorld\\XXX\\YYY" is "Base\\XXX\YYY"
        // We need to remove the "OldWorld\\" prefix
        if(!_strnicmp(szFileName, "OldWorld\\", 9))
            szFileName += 9;

        // Create the file name from the known patch entry
        memcpy(szBuffer, pPrefix->szPatchPrefix, pPrefix->nLength);
        strcpy(szBuffer + pPrefix->nLength, szFileName);
        szFileName = szBuffer;
    }

    return szFileName;
}

static bool OpenLocalFile(const char * szFileName, HANDLE * PtrFile)
{
    TFileStream * pStream;
    TMPQFile * hf = NULL;
    TCHAR szFileNameT[MAX_PATH];

    // Convert the file name to UNICODE (if needed)
    CopyFileName(szFileNameT, szFileName, strlen(szFileName));

    // Open the file and create the TMPQFile structure
    pStream = FileStream_OpenFile(szFileNameT, STREAM_FLAG_READ_ONLY);
    if(pStream != NULL)
    {
        // Allocate and initialize file handle
        hf = CreateFileHandle(NULL, NULL);
        if(hf != NULL)
        {
            hf->pStream = pStream;
            *PtrFile = hf;
            return true;
        }
        else
        {
            FileStream_Close(pStream);
            SetLastError(ERROR_NOT_ENOUGH_MEMORY);
        }
    }
    *PtrFile = NULL;
    return false;
}

bool OpenPatchedFile(HANDLE hMpq, const char * szFileName, HANDLE * PtrFile)
{
    TMPQArchive * haBase = NULL;
    TMPQArchive * ha = (TMPQArchive *)hMpq;
    TFileEntry * pFileEntry;
    TMPQFile * hfPatch;                     // Pointer to patch file
    TMPQFile * hfBase = NULL;               // Pointer to base open file
    TMPQFile * hf = NULL;
    HANDLE hPatchFile;
    char szNameBuffer[MAX_PATH];

    // First of all, find the latest archive where the file is in base version
    // (i.e. where the original, unpatched version of the file exists)
    while(ha != NULL)
    {
        // If the file is there, then we remember the archive
        pFileEntry = GetFileEntryExact(ha, GetPatchFileName(ha, szFileName, szNameBuffer), 0, NULL);
        if(pFileEntry != NULL && (pFileEntry->dwFlags & MPQ_FILE_PATCH_FILE) == 0)
            haBase = ha;

        // Move to the patch archive
        ha = ha->haPatch;
    }

    // If we couldn't find the base file in any of the patches, it doesn't exist
    if((ha = haBase) == NULL)
    {
        SetLastError(ERROR_FILE_NOT_FOUND);
        return false;
    }

    // Now open the base file
    if(SFileOpenFileEx((HANDLE)ha, GetPatchFileName(ha, szFileName, szNameBuffer), SFILE_OPEN_BASE_FILE, (HANDLE *)&hfBase))
    {
        // The file must be a base file, i.e. without MPQ_FILE_PATCH_FILE
        assert((hfBase->pFileEntry->dwFlags & MPQ_FILE_PATCH_FILE) == 0);
        hf = hfBase;

        // Now open all patches and attach them on top of the base file
        for(ha = ha->haPatch; ha != NULL; ha = ha->haPatch)
        {
            // Prepare the file name with a correct prefix
            if(SFileOpenFileEx((HANDLE)ha, GetPatchFileName(ha, szFileName, szNameBuffer), SFILE_OPEN_BASE_FILE, &hPatchFile))
            {
                // Remember the new version
                hfPatch = (TMPQFile *)hPatchFile;

                // We should not find patch file
                assert((hfPatch->pFileEntry->dwFlags & MPQ_FILE_PATCH_FILE) != 0);

                // Attach the patch to the base file
                hf->hfPatch = hfPatch;
                hf = hfPatch;
            }
        }
    }

    // Give the updated base MPQ
    if(PtrFile != NULL)
        *PtrFile = (HANDLE)hfBase;
    return (hfBase != NULL);
}

/*****************************************************************************/
/* Public functions                                                          */
/*****************************************************************************/

//-----------------------------------------------------------------------------
// SFileEnumLocales enums all locale versions within MPQ. 
// Functions fills all available language identifiers on a file into the buffer
// pointed by plcLocales. There must be enough entries to copy the localed,
// otherwise the function returns ERROR_INSUFFICIENT_BUFFER.

int WINAPI SFileEnumLocales(
    HANDLE hMpq,
    const char * szFileName,
    LCID * PtrLocales,
    LPDWORD PtrMaxLocales,
    DWORD dwSearchScope)
{
    TMPQArchive * ha = (TMPQArchive *)hMpq;
    TMPQHash * pFirstHash;
    TMPQHash * pHash;
    DWORD dwFileIndex = 0;
    DWORD dwMaxLocales;
    DWORD dwLocales = 0;

    // Test the parameters
    if(!IsValidMpqHandle(hMpq))
        return ERROR_INVALID_HANDLE;
    if(szFileName == NULL || *szFileName == 0)
        return ERROR_INVALID_PARAMETER;
    if(ha->pHashTable == NULL)
        return ERROR_NOT_SUPPORTED;
    if(PtrMaxLocales == NULL)
        return ERROR_INVALID_PARAMETER;
    if(IsPseudoFileName(szFileName, &dwFileIndex))
        return ERROR_INVALID_PARAMETER;
    
    // Keep compiler happy
    dwMaxLocales = PtrMaxLocales[0];
    dwSearchScope = dwSearchScope;

    // Parse all files with that name
    pFirstHash = pHash = GetFirstHashEntry(ha, szFileName);
    while(pHash != NULL)
    {
        // Put the locales to the buffer
        if(PtrLocales != NULL && dwLocales < dwMaxLocales)
            *PtrLocales++ = pHash->lcLocale;
        dwLocales++;

        // Get the next locale
        pHash = GetNextHashEntry(ha, pFirstHash, pHash);
    }

    // Give the caller the number of locales and return
    PtrMaxLocales[0] = dwLocales;
    return (dwLocales <= dwMaxLocales) ? ERROR_SUCCESS : ERROR_INSUFFICIENT_BUFFER;
}

//-----------------------------------------------------------------------------
// SFileOpenFileEx
//
//   hMpq          - Handle of opened MPQ archive
//   szFileName    - Name of file to open
//   dwSearchScope - Where to search
//   PtrFile       - Pointer to store opened file handle

bool WINAPI SFileOpenFileEx(HANDLE hMpq, const char * szFileName, DWORD dwSearchScope, HANDLE * PtrFile)
{
    TMPQArchive * ha = IsValidMpqHandle(hMpq);
    TFileEntry  * pFileEntry = NULL;
    TMPQFile    * hf = NULL;
    DWORD dwHashIndex = HASH_ENTRY_FREE;
    DWORD dwFileIndex = 0;
    bool bOpenByIndex = false;
    int nError = ERROR_SUCCESS;

    // Don't accept NULL pointer to file handle
    if(szFileName == NULL || *szFileName == 0)
        nError = ERROR_INVALID_PARAMETER;

    // When opening a file from MPQ, the handle must be valid
    if(dwSearchScope != SFILE_OPEN_LOCAL_FILE && ha == NULL)
        nError = ERROR_INVALID_HANDLE;

    // When not checking for existence, the pointer to file handle must be valid
    if(dwSearchScope != SFILE_OPEN_CHECK_EXISTS && PtrFile == NULL)
        nError = ERROR_INVALID_PARAMETER;

    // Prepare the file opening
    if(nError == ERROR_SUCCESS)
    {
        switch(dwSearchScope)
        {
            case SFILE_OPEN_FROM_MPQ:
            case SFILE_OPEN_BASE_FILE:
            case SFILE_OPEN_CHECK_EXISTS:
                
                // Check the pseudo-file name
                if((bOpenByIndex = IsPseudoFileName(szFileName, &dwFileIndex)) == true)
                {
                    // Get the file entry for the file
                    if(dwFileIndex > ha->dwFileTableSize)
                        break;
                    pFileEntry = ha->pFileTable + dwFileIndex;
                }
                else
                {
                    // If this MPQ has no patches, open the file from this MPQ directly
                    if(ha->haPatch == NULL || dwSearchScope == SFILE_OPEN_BASE_FILE)
                    {
                        pFileEntry = GetFileEntryLocale2(ha, szFileName, lcFileLocale, &dwHashIndex);
                    }

                    // If this MPQ is a patched archive, open the file as patched
                    else
                    {
                        return OpenPatchedFile(hMpq, szFileName, PtrFile);
                    }
                }
                break;

            case SFILE_OPEN_ANY_LOCALE:

                // This open option is reserved for opening MPQ internal listfile.
                // No argument validation. Tries to open file with neutral locale first,
                // then any other available.
                pFileEntry = GetFileEntryLocale2(ha, szFileName, 0, &dwHashIndex);
                break;

            case SFILE_OPEN_LOCAL_FILE:

                // Open a local file
                return OpenLocalFile(szFileName, PtrFile); 

            default:

                // Don't accept any other value
                nError = ERROR_INVALID_PARAMETER;
                break;
        }
    }

    // Check whether the file really exists in the MPQ
    if(nError == ERROR_SUCCESS)
    {
        if(pFileEntry == NULL || (pFileEntry->dwFlags & MPQ_FILE_EXISTS) == 0)
            nError = ERROR_FILE_NOT_FOUND;

        // Ignore unknown loading flags (example: MPQ_2016_v1_WME4_4.w3x)
//      if(pFileEntry != NULL && pFileEntry->dwFlags & ~MPQ_FILE_VALID_FLAGS)
//          nError = ERROR_NOT_SUPPORTED;
    }

    // Did the caller just wanted to know if the file exists?
    if(nError == ERROR_SUCCESS && dwSearchScope != SFILE_OPEN_CHECK_EXISTS)
    {
        // Allocate file handle
        hf = CreateFileHandle(ha, pFileEntry);
        if(hf != NULL)
        {
            // Get the hash index for the file
            if(ha->pHashTable != NULL && dwHashIndex == HASH_ENTRY_FREE)
                dwHashIndex = FindHashIndex(ha, dwFileIndex);
            if(dwHashIndex != HASH_ENTRY_FREE)
                hf->pHashEntry = ha->pHashTable + dwHashIndex;
            hf->dwHashIndex = dwHashIndex;

            // If the MPQ has sector CRC enabled, enable if for the file
            if(ha->dwFlags & MPQ_FLAG_CHECK_SECTOR_CRC)
                hf->bCheckSectorCRCs = true;

            // If we know the real file name, copy it to the file entry
            if(bOpenByIndex == false)
            {
                // If there is no file name yet, allocate it
                AllocateFileName(ha, pFileEntry, szFileName);

                // If the file is encrypted, we should detect the file key
                if(pFileEntry->dwFlags & MPQ_FILE_ENCRYPTED)
                {
                    hf->dwFileKey = DecryptFileKey(szFileName,
                                                   pFileEntry->ByteOffset,
                                                   pFileEntry->dwFileSize,
                                                   pFileEntry->dwFlags);
                }
            }
        }
        else
        {
            nError = ERROR_NOT_ENOUGH_MEMORY;
        }
    }

    // Give the file entry
    if(PtrFile != NULL)
        PtrFile[0] = hf;

    // Return error code
    if(nError != ERROR_SUCCESS)
        SetLastError(nError);
    return (nError == ERROR_SUCCESS);
}

//-----------------------------------------------------------------------------
// SFileHasFile
//
//   hMpq          - Handle of opened MPQ archive
//   szFileName    - Name of file to look for

bool WINAPI SFileHasFile(HANDLE hMpq, const char * szFileName)
{
    return SFileOpenFileEx(hMpq, szFileName, SFILE_OPEN_CHECK_EXISTS, NULL);
}

//-----------------------------------------------------------------------------
// bool WINAPI SFileCloseFile(HANDLE hFile);

bool WINAPI SFileCloseFile(HANDLE hFile)
{
    TMPQFile * hf = (TMPQFile *)hFile;
    
    if(!IsValidFileHandle(hFile))
    {
        SetLastError(ERROR_INVALID_HANDLE);
        return false;
    }

    // Free the structure
    FreeFileHandle(hf);
    return true;
}