Clean project structure.

src/base/core/streams/BitStream.cpp

@@ -0,0 +1,147 @@
+#include "BitStream.h"
+
+#include "ByteUtils.h"
+
+#include <sstream>
+#include <iostream>
+
+BitStream::~BitStream()
+{
+
+}
+
+unsigned char BitStream::getCurrentByte()
+{
+    if (mByteOffset < 0)
+    {
+        readNextByte();
+    }
+    return mCurrentByte;
+}
+
+void BitStream::write(uint32_t data)
+{
+    unsigned num_bytes = sizeof(uint32_t);
+    for(unsigned idx=0; idx<num_bytes;idx++)
+    {
+        writeByte(ByteUtils::getByteN(data, idx));
+    }
+}
+
+void BitStream::writeWord(uint16_t data)
+{
+    const auto byte0 = static_cast<unsigned char>(data >> 8);
+    const auto byte1 = static_cast<unsigned char>((data << 8) >> 8);
+    writeByte(byte0);
+    writeByte(byte1);
+}
+
+int BitStream::getCurrentByteOffset() const
+{
+    return mByteOffset;
+}
+
+unsigned BitStream::getCurrentBitOffset() const
+{
+    return mBitOffset;
+}
+
+std::string BitStream::logLocation()
+{
+    std::stringstream sstr;
+    sstr << "Byte offset " << mByteOffset<< " | Bit offset " << mBitOffset;
+    sstr << " | Working byte " << ByteUtils::toString(getCurrentByte()) << '\n';
+    return sstr.str();
+}
+
+std::string BitStream::logNextNBytes(unsigned n) const
+{
+    std::stringstream sstr;
+    unsigned count{0};
+    for(auto byte : peekNextNBytes(n))
+    {
+        sstr << mByteOffset + count << " | " << ByteUtils::toString(byte) + '\n';
+        count++;
+    }
+    return sstr.str();
+}
+
+void BitStream::writeNBits(uint32_t data, unsigned length)
+{
+    const auto num_left = 8 - mBitOffset;
+    const int overshoot = length - num_left;
+
+    if (overshoot > 0)
+    {
+        unsigned char lower_bits = ByteUtils::getLowerNBits(data, num_left);
+        mCurrentByte |= lower_bits << mBitOffset;
+
+        writeByte(mCurrentByte, false);
+
+        unsigned num_bytes = overshoot / 8;
+        for (unsigned idx=0; idx< num_bytes; idx++)
+        {
+            mCurrentByte = ByteUtils::getMBitsAtN(static_cast<unsigned char>(data), overshoot, idx*8 + num_left);
+            writeByte(mCurrentByte, false);
+        }
+
+        if (const auto remainder = overshoot % 8; remainder > 0)
+        {
+            mCurrentByte = ByteUtils::getMBitsAtN(static_cast<unsigned char>(data), remainder, num_bytes*8 + num_left);
+            mBitOffset = remainder;
+        }
+        else
+        {
+            mCurrentByte = 0;
+            mBitOffset = 0;
+        }
+    }
+    else
+    {
+        mCurrentByte |= (static_cast<unsigned char>(data) << mBitOffset);
+        mBitOffset += length;
+        if (mBitOffset == 8)
+        {
+            writeByte(mCurrentByte, false);
+            mCurrentByte = 0;
+            mBitOffset = 0;
+        }
+    }
+
+}
+
+bool BitStream::readNextNBits(unsigned n, unsigned char& buffer)
+{
+    if (mByteOffset < 0)
+    {
+        if (!readNextByte())
+        {
+            return false;
+        }
+    }
+
+    int overshoot = n + mBitOffset - 8;
+    if (overshoot > 0)
+    {
+        unsigned char last_byte = mCurrentByte;
+        if (!readNextByte())
+        {
+            return false;
+        }
+
+        auto num_lower = 8 - mBitOffset;
+        char lower_bits = ByteUtils::getHigherNBits(last_byte, num_lower);
+        char higher_bits = ByteUtils::getLowerNBits(mCurrentByte, overshoot);
+
+        buffer = (higher_bits << num_lower) | lower_bits;
+
+        mBitOffset = overshoot;
+        return true;
+    }
+    else
+    {
+        buffer = ByteUtils::getMBitsAtN(mCurrentByte, n, mBitOffset);
+        mBitOffset += n;
+        return true;
+    }
+}