CWE-ou-minkata/Sources/Plasma/PubUtilLib/plCompression/plZlibStream.cpp

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*==LICENSE==*/
#include "plZlibStream.h"
#include <zlib.h>

voidpf ZlibAlloc(voidpf opaque, uInt items, uInt size)
{
    return malloc(items*size);
}

void ZlibFree(voidpf opaque, voidpf address)
{
    free(address);
}

plZlibStream::plZlibStream() : fOutput(nil), fZStream(nil), fHeader(kNeedMoreData), fDecompressedOk(false)
{
}

plZlibStream::~plZlibStream()
{
    hsAssert(!fOutput && !fZStream, "plZlibStream not closed");
}

bool plZlibStream::Open(const plFileName& filename, const char* mode)
{
    fFilename = filename;
    fMode = mode;

    fOutput = new hsUNIXStream;
    return fOutput->Open(filename, "wb");
}

bool plZlibStream::Close()
{
    if (fOutput)
    {
        fOutput->Close();
        delete fOutput;
        fOutput = nil;
    }
    if (fZStream)
    {
        z_streamp zstream = (z_streamp)fZStream;
        inflateEnd(zstream);
        delete zstream;
        fZStream = nil;
    }

    return true;
}

uint32_t plZlibStream::Write(uint32_t byteCount, const void* buffer)
{
    uint8_t* byteBuf = (uint8_t*)buffer;

    // Check if we've read in the full gzip header yet
    if (fHeader == kNeedMoreData)
    {
        int cutAmt = IValidateGzHeader(byteCount, buffer);

        // Once we've read in the whole header, cut out whatever part of it is
        // in this buffer, leaving raw compressed data
        if (cutAmt != 0)
        {
            byteCount -= cutAmt;
            byteBuf += cutAmt;
        }
    }

    if (fHeader == kInvalidHeader)
        return 0;

    if (fHeader == kValidHeader)
    {
        ASSERT(fOutput);
        ASSERT(fZStream);
        z_streamp zstream = (z_streamp)fZStream;
        zstream->avail_in = byteCount;
        zstream->next_in = byteBuf;

        char outBuf[2048];
        while (zstream->avail_in != 0)
        {
            zstream->avail_out = sizeof(outBuf);
            zstream->next_out = (uint8_t*)outBuf;

            uint32_t amtWritten = zstream->total_out;

            int ret = inflate(zstream, Z_NO_FLUSH);

            bool inflateErr = (ret == Z_NEED_DICT || ret == Z_DATA_ERROR ||
                                ret == Z_STREAM_ERROR || ret == Z_MEM_ERROR || ret == Z_BUF_ERROR);
            // If we have a decompression error, just fail
            if (inflateErr)
            {
                hsAssert(!inflateErr, "Error in inflate");
                fHeader = kInvalidHeader;
                break;
            }

            amtWritten = zstream->total_out - amtWritten;
            fOutput->Write(amtWritten, outBuf);

            // If zlib says we hit the end of the stream, ignore avail_in
            if (ret == Z_STREAM_END)
            {
                fDecompressedOk = true;
                break;
            }
        }
    }

    return byteCount;
}

int plZlibStream::IValidateGzHeader(uint32_t byteCount, const void* buffer)
{
    // Ripped from gzio.cpp
    #define HEAD_CRC     0x02
    #define EXTRA_FIELD  0x04
    #define ORIG_NAME    0x08
    #define COMMENT      0x10
    #define RESERVED     0xE0
    static int gz_magic[2] = {0x1f, 0x8b}; // gzip magic header
    
    #define CheckForEnd() if (s.AtEnd()) { fHeader = kNeedMoreData; return 0; }

    int i;

    int initCacheSize = fHeaderCache.size();
    for (i = 0; i < byteCount; i++)
        fHeaderCache.push_back(((uint8_t*)buffer)[i]);
    hsReadOnlyStream s(fHeaderCache.size(), &fHeaderCache[0]);
    
    // Check the gzip magic header
    for (i = 0; i < 2; i++)
    {
        uint8_t c = s.ReadByte();
        if (c != gz_magic[i])
        {
            CheckForEnd();
            fHeader = kInvalidHeader;
            return 0;
        }
    }
    
    int method = s.ReadByte();
    int flags = s.ReadByte();
    if (method != Z_DEFLATED || (flags & RESERVED) != 0)
    {
        CheckForEnd();
        fHeader = kInvalidHeader;
        return 0;
    }
    
    // Discard time, xflags and OS code:
    for (i = 0; i < 6; i++)
        s.ReadByte();
    CheckForEnd();
    
    if ((flags & EXTRA_FIELD) != 0)
    {
        // skip the extra field
        uint16_t len = s.ReadLE16();
        while (len-- != 0 && s.ReadByte())
        {
            CheckForEnd();
        }
    }
    
    int c;

    // skip the original file name
    if ((flags & ORIG_NAME) != 0)
    {
        while ((c = s.ReadByte()) != 0)
        {
            CheckForEnd();
        }
    }
    
    // skip the .gz file comment
    if ((flags & COMMENT) != 0)
    {
        while ((c = s.ReadByte()) != 0)
        {
            CheckForEnd();
        }
    }

    // skip the header crc
    if ((flags & HEAD_CRC) != 0)
    {
        s.ReadLE16();
        CheckForEnd();
    }
    
    CheckForEnd();
    
    uint32_t headerSize = s.GetPosition();
    uint32_t clipBuffer = headerSize - initCacheSize;
    
    // Initialize the zlib stream
    z_streamp zstream = new z_stream_s;
    memset(zstream, 0, sizeof(z_stream_s));
    zstream->zalloc = ZlibAlloc;
    zstream->zfree = ZlibFree;
    zstream->opaque = nil;
    zstream->avail_in = byteCount - clipBuffer;
    zstream->next_in = (uint8_t*)&fHeaderCache[clipBuffer];
    // Gotta use inflateInit2, because there's no header for zlib to look at.
    // The -15 tells it to not try and find a header
    bool initOk = (inflateInit2(zstream, -15) == Z_OK);
    fZStream = zstream;

    fHeaderCache.clear();

    if (!initOk)
    {
        hsAssert(0, "Zip init failed");
        fHeader = kInvalidHeader;
        return 0;
    }
    ASSERT(fZStream);

    fHeader = kValidHeader;
    return clipBuffer;
}

bool plZlibStream::AtEnd()
{
    hsAssert(0, "AtEnd not supported");
    return true;
}

uint32_t plZlibStream::Read(uint32_t byteCount, void* buffer)
{
    hsAssert(0, "Read not supported");
    return 0;
}

void plZlibStream::Skip(uint32_t deltaByteCount)
{
    hsAssert(0, "Skip not supported");
}

void plZlibStream::Rewind()
{
    // hack so rewind will work (someone thought it would be funny to not implement base class functions)
    Close();
    Open(fFilename, fMode);
    fHeader = kNeedMoreData;
    fDecompressedOk = false;
}

void plZlibStream::FastFwd()
{
    hsAssert(0, "FastFwd not supported");
}

uint32_t plZlibStream::GetEOF()
{
    hsAssert(0, "GetEOF not supported");
    return 0;
}