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Gunzip: added GetFilename() and GetComment() methods (#418) 

Add Filename, Filtetime and Comment support to Gzip classes
pull/186/merge
c0ff 2017-05-12 22:09:21 +03:00 committed by Jeffrey Walton
parent 973de7712a
commit d901ecd9a4
2 changed files with 146 additions and 8 deletions
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111
gzip.cpp
View File

@ -5,19 +5,39 @@
NAMESPACE_BEGIN(CryptoPP)
// Checks whether the character is valid for ISO/IEC 8859-1 as required by RFC 1952
static inline bool Is8859Character(char c) {
const unsigned char cc = static_cast<unsigned char>(c);
return (cc >= 32 && cc <= 126) || (cc >= 160 && cc <= 255);
}
void Gzip::WritePrestreamHeader()
{
m_totalLen = 0;
m_crc.Restart();
int 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 = byte((GetDeflateLevel() == 1) ? FAST : ((GetDeflateLevel() == 9) ? SLOW : 0));
AttachedTransformation()->Put((byte)flags); // general flag
AttachedTransformation()->PutWord32(m_filetime, LITTLE_ENDIAN_ORDER); // time stamp
byte extra = (GetDeflateLevel() == 1) ? FAST : ((GetDeflateLevel() == 9) ? SLOW : 0);
AttachedTransformation()->Put(extra);
AttachedTransformation()->Put(GZIP_OS_CODE);
// Filename is NULL terminated, hence the +1
if(!m_filename.empty())
AttachedTransformation()->Put((const unsigned char*)m_filename.data(), m_filename.size() +1);
// Comment is NULL terminated, hence the +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)
@ -32,12 +52,44 @@ void Gzip::WritePoststreamTail()
m_crc.Final(crc);
AttachedTransformation()->Put(crc, 4);
AttachedTransformation()->PutWord32(m_totalLen, LITTLE_ENDIAN_ORDER);
m_filetime = 0;
m_filename.clear();
m_comment.clear();
}
void Gzip::SetComment(const std::string& comment, bool throwOnEncodingError)
{
if(throwOnEncodingError)
{
for(size_t i = 0; i < comment.length(); i++) {
const char c = comment[i];
if(!Is8859Character(c))
throw InvalidDataFormat("The comment is not ISO/IEC 8859-1 encoded");
}
}
m_comment = comment;
}
void Gzip::SetFilename(const std::string& filename, bool throwOnEncodingError)
{
if(throwOnEncodingError)
{
for(size_t i = 0; i < filename.length(); i++) {
const char c = filename[i];
if(!Is8859Character(c))
throw InvalidDataFormat("The filename is not ISO/IEC 8859-1 encoded");
}
}
m_filename = filename;
}
// *************************************************************
Gunzip::Gunzip(BufferedTransformation *attachment, bool repeat, int propagation)
: Inflator(attachment, repeat, propagation), m_length(0)
: Inflator(attachment, repeat, propagation), m_length(0), m_filetime(0)
{
}
@ -46,15 +98,20 @@ void Gunzip::ProcessPrestreamHeader()
m_length = 0;
m_crc.Restart();
m_filetime = 0;
m_filename.clear();
m_comment.clear();
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 +120,25 @@ void Gunzip::ProcessPrestreamHeader()
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();
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)
@ -96,4 +163,32 @@ void Gunzip::ProcessPoststreamTail()
throw LengthErr();
}
const std::string& Gunzip::GetComment(bool throwOnEncodingError) const
{
if(throwOnEncodingError)
{
for(size_t i = 0; i < m_comment.length(); i++) {
const char c = m_comment[i];
if(!Is8859Character(c))
throw InvalidDataFormat("The comment is not ISO/IEC 8859-1 encoded");
}
}
return m_comment;
}
const std::string& Gunzip::GetFilename(bool throwOnEncodingError) const
{
if(throwOnEncodingError)
{
for(size_t i = 0; i < m_filename.length(); i++) {
const char c = m_filename[i];
if(!Is8859Character(c))
throw InvalidDataFormat("The filename is not ISO/IEC 8859-1 encoded");
}
}
return m_filename;
}
NAMESPACE_END

43
gzip.h
View File

@ -35,9 +35,29 @@ public:
Gzip(const NameValuePairs &parameters, BufferedTransformation *attachment=NULLPTR)
: Deflator(parameters, attachment), m_totalLen(0) {}
//! \param filetime the filetime to set in the header. The application is responsible for setting it.
void SetFiletime(word32 filetime) { m_filetime = filetime; }
//! \param filename the original filename to set in the header. The application is responsible for setting it.
//! RFC 1952 requires a ISO/IEC 8859-1 encoding.
//! \param throwOnEncodingError if throwOnEncodingError is true, then the filename is checked to ensure it is
//! ISO/IEC 8859-1 encoded. If the filename does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat
//! is thrown. If throwOnEncodingError is false then the filename is not checked.
void SetFilename(const std::string& filename, bool throwOnEncodingError = false);
//! \param comment the comment to set in the header. The application is responsible for setting it.
//! RFC 1952 requires a ISO/IEC 8859-1 encoding.
//! \param throwOnEncodingError if throwOnEncodingError is true, then the comment is checked to ensure it is
//! ISO/IEC 8859-1 encoded. If the comment does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat
//! is thrown. If throwOnEncodingError is false then the comment is not checked.
void SetComment(const std::string& comment, bool throwOnEncodingError = false);
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);
@ -45,6 +65,10 @@ protected:
word32 m_totalLen;
CRC32 m_crc;
word32 m_filetime;
std::string m_filename;
std::string m_comment;
};
//! \class Gunzip
@ -73,6 +97,21 @@ public:
//! \param autoSignalPropagation 0 to turn off MessageEnd signal
Gunzip(BufferedTransformation *attachment = NULLPTR, bool repeat = false, int autoSignalPropagation = -1);
//! \return the filetime of the stream as set in the header. The application is responsible for setting it on the decompressed file.
word32 GetFiletime() const { return m_filetime; }
//! \return the filename of the stream as set in the header. The application is responsible for setting it on the decompressed file.
//! \param throwOnEncodingError if throwOnEncodingError is true, then the filename is checked to ensure it is
//! ISO/IEC 8859-1 encoded. If the filename does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat is thrown.
//! If throwOnEncodingError is false then the filename is not checked.
const std::string& GetFilename(bool throwOnEncodingError = false) const;
//! \return the comment of the stream as set in the header.
//! \param throwOnEncodingError if throwOnEncodingError is true, then the comment is checked to ensure it is
//! ISO/IEC 8859-1 encoded. If the comment does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat is thrown.
//! If throwOnEncodingError is false then the comment is not checked.
const std::string& GetComment(bool throwOnEncodingError = false) const;
protected:
enum {
//! \brief First header magic value
@ -94,6 +133,10 @@ protected:
word32 m_length;
CRC32 m_crc;
word32 m_filetime;
std::string m_filename;
std::string m_comment;
};
NAMESPACE_END