From: Maxim Mamontov <faust.madf@gmail.com>
Date: Sat, 21 Jun 2014 20:39:36 +0000 (+0300)
Subject: Added stream encryption/decryption.
X-Git-Url: https://git.stg.codes/stg.git/commitdiff_plain/d4c4fa8efc14b0b5e9bbca41af0e24e652a28d11

Added stream encryption/decryption.
---

diff --git a/stglibs/crypto.lib/bfstream.cpp b/stglibs/crypto.lib/bfstream.cpp
new file mode 100644
index 00000000..4f376c5d
--- /dev/null
+++ b/stglibs/crypto.lib/bfstream.cpp
@@ -0,0 +1,122 @@
+#include "stg/bfstream.h"
+
+#include "stg/blowfish.h"
+
+#include <cstring>
+
+namespace
+{
+
+#ifndef BFSTREAM_BUF_SIZE
+const size_t BUFFER_SIZE = 1024;
+#else
+const size_t BUFFER_SIZE = BFSTREAM_BUF_SIZE;
+#endif
+
+class COMMON
+{
+    public:
+        typedef void (* CALLBACK)(const void * block, size_t size, void * data);
+        typedef void (* PROC)(void * dest, const void * source, size_t length, const BLOWFISH_CTX * ctx);
+
+        COMMON(const std::string & key, CALLBACK callback, void * data, PROC proc)
+            : m_ptr(m_buffer),
+              m_callback(callback),
+              m_data(data),
+              m_proc(proc)
+        {
+        InitContext(key.c_str(), key.length(), &m_ctx);
+        }
+
+        void Put(const void * data, size_t size, bool last)
+        {
+        size_t dataSize = m_ptr - m_buffer;
+        if (dataSize + size > sizeof(m_buffer))
+            {
+            memcpy(m_ptr, data, sizeof(m_buffer) - dataSize); // Fill buffer
+            size -= sizeof(m_buffer) - dataSize; // Adjust size
+            data += sizeof(m_buffer) - dataSize; // Adjust data pointer
+            m_proc(m_buffer, m_buffer, sizeof(m_buffer), &m_ctx); // Process
+            m_callback(m_buffer, sizeof(m_buffer), m_data); // Consume
+            m_ptr = m_buffer;
+            }
+        memcpy(m_ptr, data, size);
+        m_ptr += size;
+        m_tryConsume(last);
+        }
+
+    private:
+        char m_buffer[BUFFER_SIZE];
+        char * m_ptr;
+        CALLBACK m_callback;
+        void * m_data;
+        BLOWFISH_CTX m_ctx;
+        PROC m_proc;
+
+        void m_tryConsume(bool last)
+        {
+        size_t dataSize = (m_ptr - m_buffer) & ~7;
+        size_t remainder = m_ptr - m_buffer - dataSize;
+        if (last && remainder > 0)
+            {
+            dataSize += 8;
+            remainder = 0;
+            }
+        if (dataSize == 0)
+            return;
+        m_proc(m_buffer, m_buffer, dataSize, &m_ctx);
+        m_callback(m_buffer, dataSize, m_data);
+        if (remainder > 0)
+            memmove(m_buffer, m_buffer + dataSize, remainder);
+        m_ptr = m_buffer + remainder;
+        }
+};
+
+} // namespace anonymous
+
+using STG::ENCRYPT_STREAM;
+using STG::DECRYPT_STREAM;
+
+class ENCRYPT_STREAM::IMPL : public COMMON
+{
+    public:
+        IMPL(const std::string & key, CALLBACK callback, void * data)
+            : COMMON(key, callback, data, EncryptString)
+        {}
+};
+
+class DECRYPT_STREAM::IMPL : public COMMON
+{
+    public:
+        IMPL(const std::string & key, CALLBACK callback, void * data)
+            : COMMON(key, callback, data, DecryptString)
+        {}
+};
+
+ENCRYPT_STREAM::ENCRYPT_STREAM(const std::string & key, CALLBACK callback, void * data)
+    : m_impl(new IMPL(key, callback, data))
+{}
+
+ENCRYPT_STREAM::~ENCRYPT_STREAM()
+{
+delete m_impl;
+}
+
+void ENCRYPT_STREAM::Put(const void * data, size_t size, bool last)
+{
+m_impl->Put(data, size, last);
+}
+
+DECRYPT_STREAM::DECRYPT_STREAM(const std::string & key, CALLBACK callback, void * data)
+    : m_impl(new IMPL(key, callback, data))
+{}
+
+DECRYPT_STREAM::~DECRYPT_STREAM()
+{
+delete m_impl;
+}
+
+void DECRYPT_STREAM::Put(const void * data, size_t size, bool last)
+{
+m_impl->Put(data, size, last);
+}
diff --git a/stglibs/crypto.lib/include/stg/bfstream.h b/stglibs/crypto.lib/include/stg/bfstream.h
new file mode 100644
index 00000000..41b44330
--- /dev/null
+++ b/stglibs/crypto.lib/include/stg/bfstream.h
@@ -0,0 +1,42 @@
+#ifndef __STG_STGLIBS_BF_STREAM_H__
+#define __STG_STGLIBS_BF_STREAM_H__
+
+#include <string>
+#include <cstddef> // size_t
+
+namespace STG
+{
+
+class ENCRYPT_STREAM
+{
+    public:
+        typedef void (* CALLBACK)(const void * block, size_t size, void * data);
+
+        ENCRYPT_STREAM(const std::string & key, CALLBACK callback, void * data);
+        ~ENCRYPT_STREAM();
+        void Put(const void * data, size_t size, bool last = false);
+
+    private:
+        class IMPL;
+
+        IMPL * m_impl;
+};
+
+class DECRYPT_STREAM
+{
+    public:
+        typedef void (* CALLBACK)(const void * block, size_t size, void * data);
+
+        DECRYPT_STREAM(const std::string & key, CALLBACK callback, void * data);
+        ~DECRYPT_STREAM();
+        void Put(const void * data, size_t size, bool last = false);
+
+    private:
+        class IMPL;
+
+        IMPL * m_impl;
+};
+
+} // namespace STG
+
+#endif