1 files changed, 113 insertions, 0 deletions

diff --git a/xbmc/utils/BitstreamWriter.cpp b/xbmc/utils/BitstreamWriter.cpp
new file mode 100644
index 0000000..43c0788
--- /dev/null
+++ b/xbmc/utils/BitstreamWriter.cpp
@@ -0,0 +1,113 @@
+/*
+ *  Copyright (C) 2017-2018 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "BitstreamWriter.h"
+
+CBitstreamWriter::CBitstreamWriter(uint8_t *buffer, unsigned int buffer_size, int writer_le)
+  : writer_le(writer_le)
+  , bit_buf(0)
+  , bit_left(32)
+  , buf(buffer)
+  , buf_ptr(buf)
+{
+}
+
+void CBitstreamWriter::WriteBits(int n, unsigned int value)
+{
+  // Write up to 32 bits into a bitstream.
+  unsigned int bit_buf;
+  int bit_left;
+
+  if (n == 32)
+  {
+    // Write exactly 32 bits into a bitstream.
+    // danger, recursion in play.
+    int lo = value & 0xffff;
+    int hi = value >> 16;
+    if (writer_le)
+    {
+      WriteBits(16, lo);
+      WriteBits(16, hi);
+    }
+    else
+    {
+      WriteBits(16, hi);
+      WriteBits(16, lo);
+    }
+    return;
+  }
+
+  bit_buf = this->bit_buf;
+  bit_left = this->bit_left;
+
+  if (writer_le)
+  {
+    bit_buf |= value << (32 - bit_left);
+    if (n >= bit_left) {
+      BS_WL32(buf_ptr, bit_buf);
+      buf_ptr += 4;
+      bit_buf = (bit_left == 32) ? 0 : value >> bit_left;
+      bit_left += 32;
+    }
+    bit_left -= n;
+  }
+  else
+  {
+    if (n < bit_left) {
+      bit_buf = (bit_buf << n) | value;
+      bit_left -= n;
+    }
+    else {
+      bit_buf <<= bit_left;
+      bit_buf |= value >> (n - bit_left);
+      BS_WB32(buf_ptr, bit_buf);
+      buf_ptr += 4;
+      bit_left += 32 - n;
+      bit_buf = value;
+    }
+  }
+
+  this->bit_buf = bit_buf;
+  this->bit_left = bit_left;
+}
+
+void CBitstreamWriter::SkipBits(int n)
+{
+  // Skip the given number of bits.
+  // Must only be used if the actual values in the bitstream do not matter.
+  // If n is 0 the behavior is undefined.
+  bit_left -= n;
+  buf_ptr -= 4 * (bit_left >> 5);
+  bit_left &= 31;
+}
+
+void CBitstreamWriter::FlushBits()
+{
+  if (!writer_le)
+  {
+    if (bit_left < 32)
+      bit_buf <<= bit_left;
+  }
+  while (bit_left < 32)
+  {
+
+    if (writer_le)
+    {
+      *buf_ptr++ = bit_buf;
+      bit_buf >>= 8;
+    }
+    else
+    {
+      *buf_ptr++ = bit_buf >> 24;
+      bit_buf <<= 8;
+    }
+    bit_left += 8;
+  }
+  bit_left = 32;
+  bit_buf = 0;
+}