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

2 files changed, 31 insertions, 16 deletions

diff --git a/libqpdf/Pl_AES_PDF.cc b/libqpdf/Pl_AES_PDF.cc
index c3fd03a9..1e5f81ab 100644
--- a/libqpdf/Pl_AES_PDF.cc
+++ b/libqpdf/Pl_AES_PDF.cc
@@ -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);
diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 6cfa6fb9..76567db0 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -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();