zipstrm.cpp

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/////////////////////////////////////////////////////////////////////////////
// Name:        zipstrm.cpp
// Purpose:     Streams for Zip files
// Author:      Mike Wetherell
// RCS-ID:      $Id: zipstrm.cpp,v 1.31.2.4 2006/01/18 16:32:47 JS Exp $
// Copyright:   (c) Mike Wetherell
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  #pragma implementation "zipstrm.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
  #pragma hdrstop
#endif

#ifndef WX_PRECOMP
  #include "wx/defs.h"
#endif

#if wxUSE_ZLIB && wxUSE_STREAMS && wxUSE_ZIPSTREAM

#include "wx/zipstrm.h"
#include "wx/log.h"
#include "wx/intl.h"
#include "wx/datstrm.h"
#include "wx/zstream.h"
#include "wx/mstream.h"
#include "wx/utils.h"
#include "wx/buffer.h"
#include "wx/ptr_scpd.h"
#include "wx/wfstream.h"
#include "zlib.h"

// value for the 'version needed to extract' field (20 means 2.0)
enum {
    VERSION_NEEDED_TO_EXTRACT = 20
};

// signatures for the various records (PKxx)
enum {
    CENTRAL_MAGIC = 0x02014b50,     // central directory record
    LOCAL_MAGIC   = 0x04034b50,     // local header
    END_MAGIC     = 0x06054b50,     // end of central directory record
    SUMS_MAGIC    = 0x08074b50      // data descriptor (info-zip)
};

// unix file attributes. zip stores them in the high 16 bits of the
// 'external attributes' field, hence the extra zeros.
enum {
    wxZIP_S_IFMT  = 0xF0000000,
    wxZIP_S_IFDIR = 0x40000000,
    wxZIP_S_IFREG = 0x80000000
};

// minimum sizes for the various records
enum {
    CENTRAL_SIZE  = 46,
    LOCAL_SIZE    = 30,
    END_SIZE      = 22,
    SUMS_SIZE     = 12
};

// The number of bytes that must be written to an wxZipOutputStream before
// a zip entry is created. The purpose of this latency is so that
// OpenCompressor() can see a little data before deciding which compressor
// it should use.
enum {
    OUTPUT_LATENCY = 4096
};

// Some offsets into the local header
enum {
    SUMS_OFFSET  = 14
};

IMPLEMENT_DYNAMIC_CLASS(wxZipEntry, wxArchiveEntry)
IMPLEMENT_DYNAMIC_CLASS(wxZipClassFactory, wxArchiveClassFactory)

//FORCE_LINK_ME(zipstrm)
int _wx_link_dummy_func_zipstrm();
int _wx_link_dummy_func_zipstrm()
{
    return 1;
}


/////////////////////////////////////////////////////////////////////////////
// Helpers

// read a string of a given length
//
static wxString ReadString(wxInputStream& stream, wxUint16 len, wxMBConv& conv)
{
#if wxUSE_UNICODE
    wxCharBuffer buf(len);
    stream.Read(buf.data(), len);
    wxString str(buf, conv);
#else
    wxString str;
    (void)conv;
    {
        wxStringBuffer buf(str, len);
        stream.Read(buf, len);
    }
#endif

    return str;
}

// Decode a little endian wxUint32 number from a character array
//
static inline wxUint32 CrackUint32(const char *m)
{
    const unsigned char *n = (const unsigned char*)m;
    return (n[3] << 24) | (n[2] << 16) | (n[1] << 8) | n[0];
}

// Temporarily lower the logging level in debug mode to avoid a warning
// from SeekI about seeking on a stream with data written back to it.
//
static wxFileOffset QuietSeek(wxInputStream& stream, wxFileOffset pos)
{
#ifdef __WXDEBUG__
    wxLogLevel level = wxLog::GetLogLevel();
    wxLog::SetLogLevel(wxLOG_Debug - 1);
    wxFileOffset result = stream.SeekI(pos);
    wxLog::SetLogLevel(level);
    return result;
#else
    return stream.SeekI(pos);
#endif
}


/////////////////////////////////////////////////////////////////////////////
// Stored input stream
// Trival decompressor for files which are 'stored' in the zip file.

class wxStoredInputStream : public wxFilterInputStream
{
public:
    wxStoredInputStream(wxInputStream& stream);

    void Open(wxFileOffset len) { Close(); m_len = len; }
    void Close() { m_pos = 0; m_lasterror = wxSTREAM_NO_ERROR; }

    virtual char Peek() { return wxInputStream::Peek(); }
    virtual wxFileOffset GetLength() const { return m_len; }

protected:
    virtual size_t OnSysRead(void *buffer, size_t size);
    virtual wxFileOffset OnSysTell() const { return m_pos; }

private:
    wxFileOffset m_pos;
    wxFileOffset m_len;

    DECLARE_NO_COPY_CLASS(wxStoredInputStream)
};

wxStoredInputStream::wxStoredInputStream(wxInputStream& stream)
  : wxFilterInputStream(stream),
    m_pos(0),
    m_len(0)
{
}

size_t wxStoredInputStream::OnSysRead(void *buffer, size_t size)
{
    size_t count = wx_truncate_cast(size_t,
                wxMin(size + wxFileOffset(0), m_len - m_pos + size_t(0)));
    count = m_parent_i_stream->Read(buffer, count).LastRead();
    m_pos += count;

    if (m_pos == m_len)
        m_lasterror = wxSTREAM_EOF;
    else if (!*m_parent_i_stream)
        m_lasterror = wxSTREAM_READ_ERROR;

    return count;
}


/////////////////////////////////////////////////////////////////////////////
// Stored output stream
// Trival compressor for files which are 'stored' in the zip file.

class wxStoredOutputStream : public wxFilterOutputStream
{
public:
    wxStoredOutputStream(wxOutputStream& stream) :
        wxFilterOutputStream(stream), m_pos(0) { }

    bool Close() {
        m_pos = 0;
        m_lasterror = wxSTREAM_NO_ERROR;
        return true;
    }

protected:
    virtual size_t OnSysWrite(const void *buffer, size_t size);
    virtual wxFileOffset OnSysTell() const { return m_pos; }

private:
    wxFileOffset m_pos;
    DECLARE_NO_COPY_CLASS(wxStoredOutputStream)
};

size_t wxStoredOutputStream::OnSysWrite(const void *buffer, size_t size)
{
    if (!IsOk() || !size)
        return 0;
    size_t count = m_parent_o_stream->Write(buffer, size).LastWrite();
    if (count != size)
        m_lasterror = wxSTREAM_WRITE_ERROR;
    m_pos += count;
    return count;
}


/////////////////////////////////////////////////////////////////////////////
// wxRawInputStream
//
// Used to handle the unusal case of raw copying an entry of unknown
// length. This can only happen when the zip being copied from is being
// read from a non-seekable stream, and also was original written to a
// non-seekable stream.
//
// In this case there's no option but to decompress the stream to find
// it's length, but we can still write the raw compressed data to avoid the
// compression overhead (which is the greater one).
//
// Usage is like this:
//  m_rawin = new wxRawInputStream(*m_parent_i_stream);
//  m_decomp = m_rawin->Open(OpenDecompressor(m_rawin->GetTee()));
//
// The wxRawInputStream owns a wxTeeInputStream object, the role of which
// is something like the unix 'tee' command; it is a transparent filter, but
// allows the data read to be read a second time via an extra method 'GetData'.
//
// The wxRawInputStream then draws data through the tee using a decompressor
// then instead of returning the decompressed data, retuns the raw data
// from wxTeeInputStream::GetData().

class wxTeeInputStream : public wxFilterInputStream
{
public:
    wxTeeInputStream(wxInputStream& stream);

    size_t GetCount() const { return m_end - m_start; }
    size_t GetData(char *buffer, size_t size);

    void Open();
    bool Final();

    wxInputStream& Read(void *buffer, size_t size);

protected:
    virtual size_t OnSysRead(void *buffer, size_t size);
    virtual wxFileOffset OnSysTell() const { return m_pos; }

private:
    wxFileOffset m_pos;
    wxMemoryBuffer m_buf;
    size_t m_start;
    size_t m_end;

    DECLARE_NO_COPY_CLASS(wxTeeInputStream)
};

wxTeeInputStream::wxTeeInputStream(wxInputStream& stream)
  : wxFilterInputStream(stream),
    m_pos(0), m_buf(8192), m_start(0), m_end(0)
{
}

void wxTeeInputStream::Open()
{
    m_pos = m_start = m_end = 0;
    m_lasterror = wxSTREAM_NO_ERROR;
}

bool wxTeeInputStream::Final()
{
    bool final = m_end == m_buf.GetDataLen();
    m_end = m_buf.GetDataLen();
    return final;
}

wxInputStream& wxTeeInputStream::Read(void *buffer, size_t size)
{
    size_t count = wxInputStream::Read(buffer, size).LastRead();
    m_end = m_buf.GetDataLen();
    m_buf.AppendData(buffer, count);
    return *this;
}

size_t wxTeeInputStream::OnSysRead(void *buffer, size_t size)
{
    size_t count = m_parent_i_stream->Read(buffer, size).LastRead();
    m_lasterror = m_parent_i_stream->GetLastError();
    return count;
}

size_t wxTeeInputStream::GetData(char *buffer, size_t size)
{
    if (m_wbacksize) {
        size_t len = m_buf.GetDataLen();
        len = len > m_wbacksize ? len - m_wbacksize : 0;
        m_buf.SetDataLen(len);
        if (m_end > len) {
            wxFAIL; // we've already returned data that's now being ungot
            m_end = len;
        }
        m_parent_i_stream->Reset();
        m_parent_i_stream->Ungetch(m_wback, m_wbacksize);
        free(m_wback);
        m_wback = NULL;
        m_wbacksize = 0;
        m_wbackcur = 0;
    }

    if (size > GetCount())
        size = GetCount();
    if (size) {
        memcpy(buffer, m_buf + m_start, size);
        m_start += size;
        wxASSERT(m_start <= m_end);
    }

    if (m_start == m_end && m_start > 0 && m_buf.GetDataLen() > 0) {
        size_t len = m_buf.GetDataLen();
        char *buf = (char*)m_buf.GetWriteBuf(len);
        len -= m_end;
        memmove(buf, buf + m_end, len);
        m_buf.UngetWriteBuf(len);
        m_start = m_end = 0;
    }

    return size;
}

class wxRawInputStream : public wxFilterInputStream
{
public:
    wxRawInputStream(wxInputStream& stream);
    virtual ~wxRawInputStream() { delete m_tee; }

    wxInputStream* Open(wxInputStream *decomp);
    wxInputStream& GetTee() const { return *m_tee; }

protected:
    virtual size_t OnSysRead(void *buffer, size_t size);
    virtual wxFileOffset OnSysTell() const { return m_pos; }

private:
    wxFileOffset m_pos;
    wxTeeInputStream *m_tee;

    enum { BUFSIZE = 8192 };
    wxCharBuffer m_dummy;

    DECLARE_NO_COPY_CLASS(wxRawInputStream)
};

wxRawInputStream::wxRawInputStream(wxInputStream& stream)
  : wxFilterInputStream(stream),
    m_pos(0),
    m_tee(new wxTeeInputStream(stream)),
    m_dummy(BUFSIZE)
{
}

wxInputStream *wxRawInputStream::Open(wxInputStream *decomp)
{
    if (decomp) {
        m_parent_i_stream = decomp;
        m_pos = 0;
        m_lasterror = wxSTREAM_NO_ERROR;
        m_tee->Open();
        return this;
    } else {
        return NULL;
    }
}

size_t wxRawInputStream::OnSysRead(void *buffer, size_t size)
{
    char *buf = (char*)buffer;
    size_t count = 0;

    while (count < size && IsOk())
    {
        while (m_parent_i_stream->IsOk() && m_tee->GetCount() == 0)
            m_parent_i_stream->Read(m_dummy.data(), BUFSIZE);

        size_t n = m_tee->GetData(buf + count, size - count);
        count += n;

        if (n == 0 && m_tee->Final())
            m_lasterror = m_parent_i_stream->GetLastError();
    }

    m_pos += count;
    return count;
}


/////////////////////////////////////////////////////////////////////////////
// Zlib streams than can be reused without recreating.

class wxZlibOutputStream2 : public wxZlibOutputStream
{
public:
    wxZlibOutputStream2(wxOutputStream& stream, int level) :
        wxZlibOutputStream(stream, level, wxZLIB_NO_HEADER) { }

    bool Open(wxOutputStream& stream);
    bool Close() { DoFlush(true); m_pos = wxInvalidOffset; return IsOk(); }
};

bool wxZlibOutputStream2::Open(wxOutputStream& stream)
{
    wxCHECK(m_pos == wxInvalidOffset, false);

    m_deflate->next_out = m_z_buffer;
    m_deflate->avail_out = m_z_size;
    m_pos = 0;
    m_lasterror = wxSTREAM_NO_ERROR;
    m_parent_o_stream = &stream;

    if (deflateReset(m_deflate) != Z_OK) {
        wxLogError(_("can't re-initialize zlib deflate stream"));
        m_lasterror = wxSTREAM_WRITE_ERROR;
        return false;
    }

    return true;
}

class wxZlibInputStream2 : public wxZlibInputStream
{
public:
    wxZlibInputStream2(wxInputStream& stream) :
        wxZlibInputStream(stream, wxZLIB_NO_HEADER) { }

    bool Open(wxInputStream& stream);
};

bool wxZlibInputStream2::Open(wxInputStream& stream)
{