only seed randon number generater once for aes-cbc, try to avoid compressing Metadata streams

git-svn-id: svn+q:///qpdf/trunk@818 71b93d88-0707-0410-a8cf-f5a4172ac649
This commit is contained in:
Jay Berkenbilt 2009-10-18 14:09:10 +00:00
parent 67e353e4e4
commit 4ccc9330a8
4 changed files with 43 additions and 16 deletions

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@ -1,3 +1,14 @@
2009-10-18 Jay Berkenbilt <ejb@ql.org>
* libqpdf/QPDFWriter.cc (unparseObject): avoid compressing
Metadata streams if possible.
2009-10-04 Jay Berkenbilt <ejb@ql.org>
* Implement support AES encrypt and crypt filters. Implementation
is not fully tested due to lack of test data but has been tested
for several cases.
2009-10-04 Jay Berkenbilt <ejb@ql.org>
* Add methods to QPDFWriter and corresponding command line

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@ -108,17 +108,22 @@ Pl_AES_PDF::finish()
void
Pl_AES_PDF::initializeVector()
{
std::string seed_str;
seed_str += QUtil::int_to_string((int)QUtil::get_current_time());
seed_str += " QPDF aes random";
MD5 m;
m.encodeString(seed_str.c_str());
MD5::Digest digest;
m.digest(digest);
assert(sizeof(digest) >= sizeof(unsigned int));
unsigned int seed;
memcpy((void*)(&seed), digest, sizeof(unsigned int));
srandom(seed);
static bool seeded_random = false;
if (! seeded_random)
{
std::string seed_str;
seed_str += QUtil::int_to_string((int)QUtil::get_current_time());
seed_str += " QPDF aes random";
MD5 m;
m.encodeString(seed_str.c_str());
MD5::Digest digest;
m.digest(digest);
assert(sizeof(digest) >= sizeof(unsigned int));
unsigned int seed;
memcpy((void*)(&seed), digest, sizeof(unsigned int));
srandom(seed);
seeded_random = true;
}
for (unsigned int i = 0; i < this->buf_size; ++i)
{
this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);

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@ -860,6 +860,12 @@ QPDFWriter::unparseObject(QPDFObjectHandle object, int level,
}
QPDFObjectHandle stream_dict = object.getDict();
bool is_metadata = false;
if (stream_dict.getKey("/Type").isName() &&
(stream_dict.getKey("/Type").getName() == "/Metadata"))
{
is_metadata = true;
}
bool filter = (this->stream_data_mode != s_preserve);
if (this->stream_data_mode == s_compress)
{
@ -878,7 +884,14 @@ QPDFWriter::unparseObject(QPDFObjectHandle object, int level,
}
bool normalize = false;
bool compress = false;
if (this->normalize_content && normalized_streams.count(old_id))
if (is_metadata &&
((! this->encrypted) || (this->encrypt_metadata == false)))
{
QTC::TC("qpdf", "QPDFWriter not compressing metadata");
filter = true;
compress = false;
}
else if (this->normalize_content && normalized_streams.count(old_id))
{
normalize = true;
filter = true;
@ -907,10 +920,7 @@ QPDFWriter::unparseObject(QPDFObjectHandle object, int level,
}
this->cur_stream_length = stream_data.getPointer()->getSize();
if (this->encrypted &&
stream_dict.getKey("/Type").isName() &&
(stream_dict.getKey("/Type").getName() == "/Metadata") &&
(! this->encrypt_metadata))
if (is_metadata && this->encrypted && (! this->encrypt_metadata))
{
// Don't encrypt stream data for the metadata stream
this->cur_data_key.clear();

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@ -160,3 +160,4 @@ qpdf-c called qpdf_force_pdf_version 0
qpdf-c called qpdf_init_write multiple times 0
QPDF_encryption rc4 decode string 0
QPDF_encryption rc4 decode stream 0
QPDFWriter not compressing metadata 0