1 files changed, 245 insertions, 0 deletions
diff --git a/xbmc/utils/RingBuffer.cpp b/xbmc/utils/RingBuffer.cpp
new file mode 100644
index 0000000..454f1f9
--- /dev/null
+++ b/xbmc/utils/RingBuffer.cpp
@@ -0,0 +1,245 @@
+/*
+ *  Copyright (C) 2010-2018 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 "RingBuffer.h"
+
+#include <algorithm>
+#include <cstdlib>
+#include <cstring>
+#include <mutex>
+
+/* Constructor */
+CRingBuffer::CRingBuffer()
+{
+  m_buffer = NULL;
+  m_size = 0;
+  m_readPtr = 0;
+  m_writePtr = 0;
+  m_fillCount = 0;
+}
+
+/* Destructor */
+CRingBuffer::~CRingBuffer()
+{
+  Destroy();
+}
+
+/* Create a ring buffer with the specified 'size' */
+bool CRingBuffer::Create(unsigned int size)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  m_buffer = (char*)malloc(size);
+  if (m_buffer != NULL)
+  {
+    m_size = size;
+    return true;
+  }
+  return false;
+}
+
+/* Free the ring buffer and set all values to NULL or 0 */
+void CRingBuffer::Destroy()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (m_buffer != NULL)
+  {
+    free(m_buffer);
+    m_buffer = NULL;
+  }
+  m_size = 0;
+  m_readPtr = 0;
+  m_writePtr = 0;
+  m_fillCount = 0;
+}
+
+/* Clear the ring buffer */
+void CRingBuffer::Clear()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  m_readPtr = 0;
+  m_writePtr = 0;
+  m_fillCount = 0;
+}
+
+/* Read in data from the ring buffer to the supplied buffer 'buf'. The amount
+ * read in is specified by 'size'.
+ */
+bool CRingBuffer::ReadData(char *buf, unsigned int size)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (size > m_fillCount)
+  {
+    return false;
+  }
+  if (size + m_readPtr > m_size)
+  {
+    unsigned int chunk = m_size - m_readPtr;
+    memcpy(buf, m_buffer + m_readPtr, chunk);
+    memcpy(buf + chunk, m_buffer, size - chunk);
+    m_readPtr = size - chunk;
+  }
+  else
+  {
+    memcpy(buf, m_buffer + m_readPtr, size);
+    m_readPtr += size;
+  }
+  if (m_readPtr == m_size)
+    m_readPtr = 0;
+  m_fillCount -= size;
+  return true;
+}
+
+/* Read in data from the ring buffer to another ring buffer object specified by
+ * 'rBuf'.
+ */
+bool CRingBuffer::ReadData(CRingBuffer &rBuf, unsigned int size)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (rBuf.getBuffer() == NULL)
+    rBuf.Create(size);
+
+  bool bOk = size <= rBuf.getMaxWriteSize() && size <= getMaxReadSize();
+  if (bOk)
+  {
+    unsigned int chunksize = std::min(size, m_size - m_readPtr);
+    bOk = rBuf.WriteData(&getBuffer()[m_readPtr], chunksize);
+    if (bOk && chunksize < size)
+      bOk = rBuf.WriteData(&getBuffer()[0], size - chunksize);
+    if (bOk)
+      SkipBytes(size);
+  }
+
+  return bOk;
+}
+
+/* Write data to ring buffer from buffer specified in 'buf'. Amount read in is
+ * specified by 'size'.
+ */
+bool CRingBuffer::WriteData(const char *buf, unsigned int size)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (size > m_size - m_fillCount)
+  {
+    return false;
+  }
+  if (size + m_writePtr > m_size)
+  {
+    unsigned int chunk = m_size - m_writePtr;
+    memcpy(m_buffer + m_writePtr, buf, chunk);
+    memcpy(m_buffer, buf + chunk, size - chunk);
+    m_writePtr = size - chunk;
+  }
+  else
+  {
+    memcpy(m_buffer + m_writePtr, buf, size);
+    m_writePtr += size;
+  }
+  if (m_writePtr == m_size)
+    m_writePtr = 0;
+  m_fillCount += size;
+  return true;
+}
+
+/* Write data to ring buffer from another ring buffer object specified by
+ * 'rBuf'.
+ */
+bool CRingBuffer::WriteData(CRingBuffer &rBuf, unsigned int size)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (m_buffer == NULL)
+    Create(size);
+
+  bool bOk = size <= rBuf.getMaxReadSize() && size <= getMaxWriteSize();
+  if (bOk)
+  {
+    unsigned int readpos = rBuf.getReadPtr();
+    unsigned int chunksize = std::min(size, rBuf.getSize() - readpos);
+    bOk = WriteData(&rBuf.getBuffer()[readpos], chunksize);
+    if (bOk && chunksize < size)
+      bOk = WriteData(&rBuf.getBuffer()[0], size - chunksize);
+  }
+
+  return bOk;
+}
+
+/* Skip bytes in buffer to be read */
+bool CRingBuffer::SkipBytes(int skipSize)
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  if (skipSize < 0)
+  {
+    return false; // skipping backwards is not supported
+  }
+
+  unsigned int size = skipSize;
+  if (size > m_fillCount)
+  {
+    return false;
+  }
+  if (size + m_readPtr > m_size)
+  {
+    unsigned int chunk = m_size - m_readPtr;
+    m_readPtr = size - chunk;
+  }
+  else
+  {
+    m_readPtr += size;
+  }
+  if (m_readPtr == m_size)
+    m_readPtr = 0;
+  m_fillCount -= size;
+  return true;
+}
+
+/* Append all content from ring buffer 'rBuf' to this ring buffer */
+bool CRingBuffer::Append(CRingBuffer &rBuf)
+{
+  return WriteData(rBuf, rBuf.getMaxReadSize());
+}
+
+/* Copy all content from ring buffer 'rBuf' to this ring buffer overwriting any existing data */
+bool CRingBuffer::Copy(CRingBuffer &rBuf)
+{
+  Clear();
+  return Append(rBuf);
+}
+
+/* Our various 'get' methods */
+char *CRingBuffer::getBuffer()
+{
+  return m_buffer;
+}
+
+unsigned int CRingBuffer::getSize()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  return m_size;
+}
+
+unsigned int CRingBuffer::getReadPtr() const
+{
+  return m_readPtr;
+}
+
+unsigned int CRingBuffer::getWritePtr()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  return m_writePtr;
+}
+
+unsigned int CRingBuffer::getMaxReadSize()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  return m_fillCount;
+}
+
+unsigned int CRingBuffer::getMaxWriteSize()
+{
+  std::unique_lock<CCriticalSection> lock(m_critSection);
+  return m_size - m_fillCount;
+}