[refactoring] move some libraries in to library directory

1 files changed, 88 insertions, 0 deletions

diff --git a/src/lib/bitstream/bitstream.cpp b/src/lib/bitstream/bitstream.cpp
new file mode 100644
index 0000000..ddff907
--- /dev/null
+++ b/src/lib/bitstream/bitstream.cpp
@@ -0,0 +1,88 @@
+/*
+ * This file is part of AtracDEnc.
+ *
+ * AtracDEnc is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * AtracDEnc is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with AtracDEnc; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <cstdint>
+#include "bitstream.h"
+
+#ifndef BIGENDIAN_ORDER
+#define NBITSTREAM__LITTLE_ENDIAN_CPU
+#endif
+
+namespace NBitStream {
+
+union UBytes {
+	uint32_t ui = 0;
+	uint8_t bytes[4];
+};
+
+TBitStream::TBitStream(const char* buf, int size)
+    : Buf(buf, buf+size)
+{}
+
+TBitStream::TBitStream()
+{}
+
+void TBitStream::Write(uint32_t val, int n) {
+    if (n > 23 || n < 0)
+        abort();
+    const int bitsLeft = Buf.size() * 8 - BitsUsed;
+    const int bitsReq = n - bitsLeft;
+    const int bytesPos = BitsUsed / 8;
+    const int overlap = BitsUsed % 8;
+
+    if (overlap || bitsReq >= 0) {
+        Buf.resize(Buf.size() + (bitsReq / 8 + (overlap ? 2 : 1 )), 0);
+    }
+    UBytes t;
+    t.ui = (val << (32 - n) >> overlap);
+
+    for (int i = 0; i < n/8 + (overlap ? 2 : 1); ++i) {
+#ifdef NBITSTREAM__LITTLE_ENDIAN_CPU
+        Buf[bytesPos+i] |= t.bytes[3-i];
+#else
+        Buf[bytesPos + i] |= t.bytes[i];
+#endif
+    }
+
+    BitsUsed += n;
+}
+
+uint32_t TBitStream::Read(int n) {
+    if (n >23 || n < 0)
+        abort();
+    const int bytesPos = ReadPos / 8;
+    const int overlap = ReadPos % 8;
+
+    UBytes t;
+    for (int i = 0; i < n/8 + (overlap ? 2 : 1); ++i) {
+#ifdef NBITSTREAM__LITTLE_ENDIAN_CPU
+        t.bytes[3-i] = (uint8_t)Buf[bytesPos+i];
+#else
+        t.bytes[i] = (uint8_t)Buf[bytesPos+i];
+#endif
+    }
+    
+    t.ui = (t.ui << overlap >> (32 - n));
+    ReadPos += n;
+    return t.ui;
+}
+
+unsigned long long TBitStream::GetSizeInBits() const {
+    return BitsUsed;
+}
+
+}