add generic digest class

Change-Id: Ic5d2d8fbb0bb4edc4c966e185be81f6ca673950e
Reviewed-on: https://gerrit.libreoffice.org/36790
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

comphelper/Library_comphelper.mk

@@ -43,6 +43,20 @@ $(eval $(call gb_Library_use_externals,comphelper,\
     zlib \
 ))
 
+ifeq ($(TLS),NSS)
+$(eval $(call gb_Library_use_externals,comphelper,\
+       plc4 \
+       nss3 \
+))
+else
+ifeq ($(TLS),OPENSSL)
+$(eval $(call gb_Library_use_externals,comphelper,\
+	openssl \
+	openssl_headers \
+))
+endif
+endif
+
 $(eval $(call gb_Library_use_libraries,comphelper,\
     cppu \
     cppuhelper \
@@ -91,6 +105,7 @@ $(eval $(call gb_Library_add_exception_objects,comphelper,\
     comphelper/source/misc/evtmethodhelper \
     comphelper/source/misc/fileurl \
     comphelper/source/misc/getexpandeduri \
+    comphelper/source/misc/hash \
     comphelper/source/misc/instancelocker \
     comphelper/source/misc/interaction \
     comphelper/source/misc/listenernotification \

comphelper/source/misc/hash.cxx

@@ -0,0 +1,144 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <comphelper/hash.hxx>
+#include <config_oox.h>
+
+#if USE_TLS_NSS
+#include <nss.h>
+#include <pk11pub.h>
+#include <sechash.h>
+#elif USE_TLS_OPENSSL
+#include <openssl/evp.h>
+#include <openssl/sha.h>
+#endif // USE_TLS_OPENSSL
+
+namespace comphelper {
+
+struct HashImpl
+{
+
+#if USE_TLS_NSS
+    HASHContext* mpContext;
+
+    HASH_HashType getNSSType() const
+    {
+        switch (meType)
+        {
+            case HashType::SHA1:
+                return HASH_AlgSHA1;
+            case HashType::SHA256:
+                return HASH_AlgSHA256;
+            case HashType::SHA512:
+                return HASH_AlgSHA512;
+        }
+
+        return HASH_AlgNULL;
+    }
+#elif USE_TLS_OPENSSL
+    EVP_MD_CTX* mpContext;
+
+    EVP_MD* getOpenSSLType() const
+    {
+        switch (meType)
+        {
+            case HashType::SHA1:
+                return EVP_sha1();
+            case HashType::SHA256:
+                return EVP_sha256();
+            case HashType::SHA512:
+                return EVP_sha512();
+        }
+
+        return nullptr;
+    }
+#endif
+
+    HashType meType;
+
+    HashImpl(HashType eType):
+        meType(eType)
+    {
+
+#if USE_TLS_NSS
+        NSS_NoDB_Init(nullptr);
+        mpContext = HASH_Create(getNSSType());
+        HASH_Begin(mpContext);
+#elif USE_TLS_OPENSSL
+        mpContext = EVP_MD_CTX_create();
+        EVP_DigestInit_ex(mpContext, getOpenSSLType(), NULL);
+#endif
+    }
+
+    ~HashImpl()
+    {
+#if USE_TLS_NSS
+        HASH_Destroy(mpContext);
+#elif USE_TLS_OPENSSL
+        EVP_MD_CTX_destroy(mpContext);
+#endif
+    }
+};
+
+Hash::Hash(HashType eType):
+    mpImpl(new HashImpl(eType))
+{
+}
+
+Hash::~Hash()
+{
+}
+
+void Hash::update(const unsigned char* pInput, size_t length)
+{
+#if USE_TLS_NSS
+    HASH_Update(mpImpl->mpContext, pInput, length);
+#elif USE_TLS_OPENSSL
+    EVP_DigestUpdate(mpImpl->mpContext, pInput, length);
+#endif
+}
+
+std::vector<unsigned char> Hash::finalize()
+{
+    std::vector<unsigned char> hash(getLength(), 0);
+    unsigned int digestWrittenLength;
+#if USE_TLS_NSS
+    HASH_End(mpImpl->mpContext, hash.data(), &digestWrittenLength, getLength());
+#elif USE_TLS_OPENSSL
+    EVP_DigestFinal_ex(mpImpl->mpContext, hash.data(), &digestWrittenLength);
+#endif
+
+    return hash;
+}
+
+size_t Hash::getLength() const
+{
+    switch (mpImpl->meType)
+    {
+        case HashType::SHA1:
+            return 20;
+        case HashType::SHA256:
+            return 32;
+        case HashType::SHA512:
+            return 64;
+    }
+
+    return 0;
+}
+
+std::vector<unsigned char> Hash::calculateHash(const unsigned char* pInput, size_t length, HashType eType)
+{
+    Hash aHash(eType);
+    aHash.update(pInput, length);
+    return aHash.finalize();
+}
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

include/comphelper/hash.hxx

@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <comphelper/comphelperdllapi.h>
+
+#include <memory>
+#include <vector>
+
+namespace comphelper {
+
+enum class HashType
+{
+    SHA1,
+    SHA256,
+    SHA512
+};
+
+struct HashImpl;
+
+class COMPHELPER_DLLPUBLIC Hash
+{
+private:
+    std::unique_ptr<HashImpl> mpImpl;
+
+public:
+
+    Hash(HashType eType);
+    ~Hash();
+
+    void update(const unsigned char* pInput, size_t length);
+
+    std::vector<unsigned char> finalize();
+
+    static std::vector<unsigned char> calculateHash(const unsigned char* pInput, size_t length, HashType eType);
+
+    size_t getLength() const;
+};
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */