SHA2: switch to pluggable crypto

1 files changed, 92 insertions, 0 deletions

diff --git a/libqpdf/Pl_SHA2.cc b/libqpdf/Pl_SHA2.cc
new file mode 100644
index 00000000..3da78773
--- /dev/null
+++ b/libqpdf/Pl_SHA2.cc
@@ -0,0 +1,92 @@
+#include <qpdf/Pl_SHA2.hh>
+#include <stdexcept>
+#include <cstdio>
+#include <qpdf/PointerHolder.hh>
+#include <qpdf/QUtil.hh>
+#include <qpdf/QPDFCryptoProvider.hh>
+
+Pl_SHA2::Pl_SHA2(int bits, Pipeline* next) :
+    Pipeline("sha2", next),
+    in_progress(false)
+{
+    if (bits)
+    {
+        resetBits(bits);
+    }
+}
+
+Pl_SHA2::~Pl_SHA2()
+{
+}
+
+void
+Pl_SHA2::write(unsigned char* buf, size_t len)
+{
+    if (! this->in_progress)
+    {
+	this->in_progress = true;
+    }
+
+    // Write in chunks in case len is too big to fit in an int.
+    // Assume int is at least 32 bits.
+    static size_t const max_bytes = 1 << 30;
+    size_t bytes_left = len;
+    unsigned char* data = buf;
+    while (bytes_left > 0)
+    {
+	size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left);
+        this->crypto->SHA2_update(data, bytes);
+	bytes_left -= bytes;
+        data += bytes;
+    }
+
+    if (this->getNext(true))
+    {
+        this->getNext()->write(buf, len);
+    }
+}
+
+void
+Pl_SHA2::finish()
+{
+    if (this->getNext(true))
+    {
+        this->getNext()->finish();
+    }
+    this->crypto->SHA2_finalize();
+    this->in_progress = false;
+}
+
+void
+Pl_SHA2::resetBits(int bits)
+{
+    if (this->in_progress)
+    {
+	throw std::logic_error(
+	    "bit reset requested for in-progress SHA2 Pipeline");
+    }
+    this->crypto = QPDFCryptoProvider::getImpl();
+    this->crypto->SHA2_init(bits);
+}
+
+std::string
+Pl_SHA2::getRawDigest()
+{
+    if (this->in_progress)
+    {
+	throw std::logic_error(
+	    "digest requested for in-progress SHA2 Pipeline");
+    }
+    return this->crypto->SHA2_digest();
+}
+
+std::string
+Pl_SHA2::getHexDigest()
+{
+    if (this->in_progress)
+    {
+	throw std::logic_error(
+	    "digest requested for in-progress SHA2 Pipeline");
+    }
+    return QUtil::hex_encode(getRawDigest());
+}