Partially implemented BitStream class - only write() so far.

libuavcan/include/uavcan/internal/marshalling/bit_stream.hpp

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#pragma once
+
+#include <cassert>
+#include <stdint.h>
+#include <string>
+#include <uavcan/internal/util.hpp>
+#include <uavcan/internal/transport/transfer_buffer.hpp>
+
+namespace uavcan
+{
+
+extern "C" void bitarray_copy(const unsigned char *src_org, int src_offset, int src_len,
+                                    unsigned char *dst_org, int dst_offset);
+
+class BitStream
+{
+    enum { MAX_BYTES_PER_RW = 16 };
+
+    ITransferBuffer& buf_;
+    int bit_offset_;
+    uint8_t byte_cache_;
+
+    static inline unsigned int bitlenToBytelen(unsigned int bits) { return (bits + 7) / 8; }
+
+    static inline void copyBitArray(const uint8_t* src_org, int src_offset, int src_len,
+                                          uint8_t* dst_org, int dst_offset)
+    {
+        bitarray_copy(reinterpret_cast<const unsigned char*>(src_org), src_offset, src_len,
+                      reinterpret_cast<unsigned char*>(dst_org), dst_offset);
+    }
+
+public:
+    BitStream(ITransferBuffer& buf)
+    : buf_(buf)
+    , bit_offset_(0)
+    , byte_cache_(0)
+    {
+        StaticAssert<sizeof(uint8_t) == 1>::check();
+    }
+
+    int write(const uint8_t* bytes, const int bitlen);
+
+    std::string toString() const;
+};
+
+}