libbpg-0.9.3

jctvc/TLibCommon/TComBitStream.h

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+/* The copyright in this software is being made available under the BSD
+ * License, included below. This software may be subject to other third party
+ * and contributor rights, including patent rights, and no such rights are
+ * granted under this license.
+ *
+ * Copyright (c) 2010-2014, ITU/ISO/IEC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *  * Neither the name of the ITU/ISO/IEC nor the names of its contributors may
+ *    be used to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file     TComBitStream.h
+    \brief    class for handling bitstream (header)
+*/
+
+#ifndef __TCOMBITSTREAM__
+#define __TCOMBITSTREAM__
+
+#if _MSC_VER > 1000
+#pragma once
+#endif // _MSC_VER > 1000
+
+#include <stdint.h>
+#include <vector>
+#include <stdio.h>
+#include <assert.h>
+#include "CommonDef.h"
+
+//! \ingroup TLibCommon
+//! \{
+
+// ====================================================================================================================
+// Class definition
+// ====================================================================================================================
+
+/// pure virtual class for basic bit handling
+class TComBitIf
+{
+public:
+  virtual Void        writeAlignOne         () {};
+  virtual Void        writeAlignZero        () {};
+  virtual Void        write                 ( UInt uiBits, UInt uiNumberOfBits )  = 0;
+  virtual Void        resetBits             ()                                    = 0;
+  virtual UInt getNumberOfWrittenBits() const = 0;
+  virtual ~TComBitIf() {}
+};
+
+/**
+ * Model of a writable bitstream that accumulates bits to produce a
+ * bytestream.
+ */
+class TComOutputBitstream : public TComBitIf
+{
+  /**
+   * FIFO for storage of bytes.  Use:
+   *  - fifo.push_back(x) to append words
+   *  - fifo.clear() to empty the FIFO
+   *  - &fifo.front() to get a pointer to the data array.
+   *    NB, this pointer is only valid until the next push_back()/clear()
+   */
+  std::vector<uint8_t> m_fifo;
+
+  UInt m_num_held_bits; /// number of bits not flushed to bytestream.
+  UChar m_held_bits; /// the bits held and not flushed to bytestream.
+                             /// this value is always msb-aligned, bigendian.
+public:
+  // create / destroy
+  TComOutputBitstream();
+  ~TComOutputBitstream();
+
+  // interface for encoding
+  /**
+   * append uiNumberOfBits least significant bits of uiBits to
+   * the current bitstream
+   */
+  Void        write           ( UInt uiBits, UInt uiNumberOfBits );
+
+  /** insert one bits until the bitstream is byte-aligned */
+  Void        writeAlignOne   ();
+
+  /** insert zero bits until the bitstream is byte-aligned */
+  Void        writeAlignZero  ();
+
+  /** this function should never be called */
+  Void resetBits() { assert(0); }
+
+  // utility functions
+
+  /**
+   * Return a pointer to the start of the byte-stream buffer.
+   * Pointer is valid until the next write/flush/reset call.
+   * NB, data is arranged such that subsequent bytes in the
+   * bytestream are stored in ascending addresses.
+   */
+  Char* getByteStream() const;
+
+  /**
+   * Return the number of valid bytes available from  getByteStream()
+   */
+  UInt getByteStreamLength();
+
+  /**
+   * Reset all internal state.
+   */
+  Void clear();
+
+  /**
+   * returns the number of bits that need to be written to
+   * achieve byte alignment.
+   */
+  Int getNumBitsUntilByteAligned() { return (8 - m_num_held_bits) & 0x7; }
+
+  /**
+   * Return the number of bits that have been written since the last clear()
+   */
+  UInt getNumberOfWrittenBits() const { return UInt(m_fifo.size()) * 8 + m_num_held_bits; }
+
+  Void insertAt(const TComOutputBitstream& src, UInt pos);
+
+  /**
+   * Return a reference to the internal fifo
+   */
+  std::vector<uint8_t>& getFIFO() { return m_fifo; }
+
+  UChar getHeldBits  ()          { return m_held_bits;          }
+
+  //TComOutputBitstream& operator= (const TComOutputBitstream& src);
+  /** Return a reference to the internal fifo */
+  const std::vector<uint8_t>& getFIFO() const { return m_fifo; }
+
+  Void          addSubstream    ( TComOutputBitstream* pcSubstream );
+  Void writeByteAlignment();
+
+  //! returns the number of start code emulations contained in the current buffer
+  Int countStartCodeEmulations();
+};
+
+/**
+ * Model of an input bitstream that extracts bits from a predefined
+ * bytestream.
+ */
+class TComInputBitstream
+{
+  std::vector<uint8_t> *m_fifo; /// FIFO for storage of complete bytes
+  std::vector<UInt> m_emulationPreventionByteLocation;
+
+protected:
+  UInt m_fifo_idx; /// Read index into m_fifo
+
+  UInt m_num_held_bits;
+  UChar m_held_bits;
+  UInt  m_numBitsRead;
+
+public:
+  /**
+   * Create a new bitstream reader object that reads from #buf#.  Ownership
+   * of #buf# remains with the callee, although the constructed object
+   * will hold a reference to #buf#
+   */
+  TComInputBitstream(std::vector<uint8_t>* buf);
+  ~TComInputBitstream();
+
+  // interface for decoding
+  Void        pseudoRead      ( UInt uiNumberOfBits, UInt& ruiBits );
+  Void        read            ( UInt uiNumberOfBits, UInt& ruiBits );
+  Void        readByte        ( UInt &ruiBits )
+  {
+    assert(m_fifo_idx < m_fifo->size());
+    ruiBits = (*m_fifo)[m_fifo_idx++];
+  }
+
+  Void        peekPreviousByte( UInt &byte )
+  {
+    assert(m_fifo_idx > 0);
+    byte = (*m_fifo)[m_fifo_idx - 1];
+  }
+
+  UInt        readOutTrailingBits ();
+  UChar getHeldBits  ()          { return m_held_bits;          }
+  TComOutputBitstream& operator= (const TComOutputBitstream& src);
+  UInt  getByteLocation              ( )                     { return m_fifo_idx                    ; }
+
+  // Peek at bits in word-storage. Used in determining if we have completed reading of current bitstream and therefore slice in LCEC.
+  UInt        peekBits (UInt uiBits) { UInt tmp; pseudoRead(uiBits, tmp); return tmp; }
+
+  // utility functions
+  UInt read(UInt numberOfBits) { UInt tmp; read(numberOfBits, tmp); return tmp; }
+  UInt     readByte() { UInt tmp; readByte( tmp ); return tmp; }
+  UInt getNumBitsUntilByteAligned() { return m_num_held_bits & (0x7); }
+  UInt getNumBitsLeft() { return 8*((UInt)m_fifo->size() - m_fifo_idx) + m_num_held_bits; }
+  TComInputBitstream *extractSubstream( UInt uiNumBits ); // Read the nominated number of bits, and return as a bitstream.
+  Void                deleteFifo(); // Delete internal fifo of bitstream.
+  UInt  getNumBitsRead() { return m_numBitsRead; }
+  UInt readByteAlignment();
+
+  Void      pushEmulationPreventionByteLocation ( UInt pos )                  { m_emulationPreventionByteLocation.push_back( pos ); }
+  UInt      numEmulationPreventionBytesRead     ()                            { return (UInt) m_emulationPreventionByteLocation.size();    }
+  std::vector<UInt>  getEmulationPreventionByteLocation  ()                   { return m_emulationPreventionByteLocation;           }
+  UInt      getEmulationPreventionByteLocation  ( UInt idx )                  { return m_emulationPreventionByteLocation[ idx ];    }
+  Void      clearEmulationPreventionByteLocation()                            { m_emulationPreventionByteLocation.clear();          }
+  Void      setEmulationPreventionByteLocation  ( std::vector<UInt> vec )     { m_emulationPreventionByteLocation = vec;            }
+};
+
+//! \}
+
+#endif