Diff for Crypto++ gzip for filename and comment processing

Index: gzip.h
===================================================================
--- gzip.h  (revision 541)
+++ gzip.h  (working copy)
@@ -12,13 +12,20 @@
 {
 public:
    Gzip(BufferedTransformation *attachment=NULL, unsigned int deflateLevel=DEFAULT_DEFLATE_LEVEL, unsigned int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true)
-       : Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible) {}
+       : Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible), m_filetime(0) {}
    Gzip(const NameValuePairs &parameters, BufferedTransformation *attachment=NULL)
-       : Deflator(parameters, attachment) {}
+       : Deflator(parameters, attachment), m_filetime(0) {}
+
+    void SetFiletime(word32 filetime) { m_filetime = filetime; }
+    void SetFilename(const std::string& filename) { m_filename = filename; }
+    void SetComment(const std::string& comment) { m_comment = comment; }

 protected:
    enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header
          DEFLATED=8, FAST=4, SLOW=2};
+
+    enum FLAG_MASKS {
+       FILENAME=8, COMMENTS=16};

    void WritePrestreamHeader();
    void ProcessUncompressedData(const byte *string, size_t length);
@@ -26,6 +33,10 @@

    word32 m_totalLen;
    CRC32 m_crc;
+
+    word32 m_filetime;
+    std::string m_filename;
+    std::string m_comment;
 };

 /// GZIP Decompression (RFC 1952)
@@ -42,6 +53,10 @@
        \param autoSignalPropagation 0 to turn off MessageEnd signal
    */
    Gunzip(BufferedTransformation *attachment = NULL, bool repeat = false, int autoSignalPropagation = -1);
+
+    word32 GetFiletime() const { return m_filetime; }
+    const std::string& GetFilename() const { return m_filename; }
+    const std::string& GetComment() const { return m_comment; }

 protected:
    enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header
@@ -58,6 +73,10 @@

    word32 m_length;
    CRC32 m_crc;
+
+    word32 m_filetime;
+    std::string m_filename;
+    std::string m_comment;
 };

 NAMESPACE_END
Index: gzip.cpp
===================================================================
--- gzip.cpp    (revision 541)
+++ gzip.cpp    (working copy)
@@ -9,15 +9,27 @@
 {
    m_totalLen = 0;
    m_crc.Restart();
+
+    word32 flags = 0;
+    if(!m_filename.empty())
+        flags |= FILENAME;
+    if(!m_comment.empty())
+        flags |= COMMENTS;

    AttachedTransformation()->Put(MAGIC1);
    AttachedTransformation()->Put(MAGIC2);
    AttachedTransformation()->Put(DEFLATED);
-   AttachedTransformation()->Put(0);       // general flag
-   AttachedTransformation()->PutWord32(0); // time stamp
-   byte extra = (GetDeflateLevel() == 1) ? FAST : ((GetDeflateLevel() == 9) ? SLOW : 0);
+   AttachedTransformation()->Put(flags);               // general flag
+   AttachedTransformation()->PutWord32(m_filetime);    // time stamp
+    byte extra = (GetDeflateLevel() == 1) ? FAST : ((GetDeflateLevel() == 9) ? SLOW : 0);
    AttachedTransformation()->Put(extra);
-   AttachedTransformation()->Put(GZIP_OS_CODE);
+    AttachedTransformation()->Put(GZIP_OS_CODE);
+
+    if(!m_filename.empty())
+        AttachedTransformation()->Put((const unsigned char*)m_filename.data(), m_filename.size() +1);
+
+    if(!m_comment.empty())
+        AttachedTransformation()->Put((const unsigned char*)m_comment.data(), m_comment.size() +1);
 }

 void Gzip::ProcessUncompressedData(const byte *inString, size_t length)
@@ -37,7 +49,7 @@
 // *************************************************************

 Gunzip::Gunzip(BufferedTransformation *attachment, bool repeat, int propagation)
-   : Inflator(attachment, repeat, propagation)
+   : Inflator(attachment, repeat, propagation), m_filetime(0)
 {
 }

@@ -45,16 +57,25 @@
 {
    m_length = 0;
    m_crc.Restart();
+
+    m_filetime = 0;
+
+    m_filename.erase(0);
+    m_filename.reserve(16);
+
+    m_comment.erase(0);
+    m_comment.reserve(32);

    byte buf[6];
    byte b, flags;

    if (m_inQueue.Get(buf, 2)!=2) throw HeaderErr();
    if (buf[0] != MAGIC1 || buf[1] != MAGIC2) throw HeaderErr();
-   if (!m_inQueue.Skip(1)) throw HeaderErr();   // skip extra flags
+   if (!m_inQueue.Get(b) || (b != DEFLATED)) throw HeaderErr();     // skip CM flag
    if (!m_inQueue.Get(flags)) throw HeaderErr();
    if (flags & (ENCRYPTED | CONTINUED)) throw HeaderErr();
-   if (m_inQueue.Skip(6)!=6) throw HeaderErr();    // Skip file time, extra flags and OS type
+    if (m_inQueue.GetWord32(m_filetime, LITTLE_ENDIAN_ORDER) != 4) throw HeaderErr();
+   if (m_inQueue.Skip(2)!=2) throw HeaderErr();    // Skip extra flags and OS type

    if (flags & EXTRA_FIELDS)   // skip extra fields
    {
@@ -63,15 +84,25 @@
        if (m_inQueue.Skip(length)!=length) throw HeaderErr();
    }

-   if (flags & FILENAME)   // skip filename
+   if (flags & FILENAME)   // extract filename
+    {
        do
+        {
            if(!m_inQueue.Get(b)) throw HeaderErr();
-       while (b);
+            if(b) m_filename.append( 1, (char)b );
+       }
+        while (b);
+    }

-   if (flags & COMMENTS)   // skip comments
+   if (flags & COMMENTS)   // extract comments
+    {
        do
+        {
            if(!m_inQueue.Get(b)) throw HeaderErr();
+            if(b) m_comment.append( 1, (char)b );
+        }
        while (b);
+    }
 }

 void Gunzip::ProcessDecompressedData(const byte *inString, size_t length)