Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
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// gzip.cpp - originally written and placed in the public domain by Wei Dai
#include "pch.h"
#include "gzip.h"
#include "argnames.h"
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);
}
void Gzip::IsolatedInitialize(const NameValuePairs &parameters)
{
Deflator::IsolatedInitialize(parameters);
ConstByteArrayParameter v;
if (parameters.GetValue(Name::FileName(), v))
m_filename.assign(reinterpret_cast<const char*>(v.begin()), v.size());
if (parameters.GetValue(Name::Comment(), v))
m_comment.assign(reinterpret_cast<const char*>(v.begin()), v.size());
m_filetime = parameters.GetIntValueWithDefault(Name::FileTime(), 0);
}
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((byte)flags); // general flag
AttachedTransformation()->PutWord32(m_filetime, LITTLE_ENDIAN_ORDER); // time stamp
byte extra = static_cast<byte>((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)
{
m_crc.Update(inString, length);
m_totalLen += (word32)length;
}
void Gzip::WritePoststreamTail()
{
SecByteBlock crc(4);
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), m_filetime(0)
{
}
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.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.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
{
word16 length;
if (m_inQueue.GetWord16(length, LITTLE_ENDIAN_ORDER) != 2) throw HeaderErr();
if (m_inQueue.Skip(length)!=length) throw HeaderErr();
}
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) // 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)
{
AttachedTransformation()->Put(inString, length);
m_crc.Update(inString, length);
m_length += (word32)length;
}
void Gunzip::ProcessPoststreamTail()
{
SecByteBlock crc(4);
if (m_inQueue.Get(crc, 4) != 4)
throw TailErr();
if (!m_crc.Verify(crc))
throw CrcErr();
word32 lengthCheck;
if (m_inQueue.GetWord32(lengthCheck, LITTLE_ENDIAN_ORDER) != 4)
throw TailErr();
if (lengthCheck != m_length)
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