/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * RemoteFX Codec Library - Bit Stream

 *

 * Copyright 2011 Vic Lee

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef FREERDP_LIB_CODEC_RFX_BITSTREAM_H

#define FREERDP_LIB_CODEC_RFX_BITSTREAM_H

#include <winpr/assert.h>

#include <winpr/cast.h>

#include <freerdp/codec/rfx.h>

#ifdef __cplusplus

extern "C"

{

#endif

  typedef struct

  {

    BYTE* buffer;

    uint32_t nbytes;

    uint32_t byte_pos;

    uint32_t bits_left;

  } RFX_BITSTREAM;

  static inline void rfx_bitstream_attach(RFX_BITSTREAM* bs, BYTE* WINPR_RESTRICT buffer,

                                          size_t nbytes)

  {

    WINPR_ASSERT(bs);

    bs->buffer = (buffer);

    WINPR_ASSERT(nbytes <= UINT32_MAX);

    bs->nbytes = WINPR_ASSERTING_INT_CAST(uint32_t, nbytes);

    bs->byte_pos = 0;

    bs->bits_left = 8;

  }

  WINPR_ATTR_NODISCARD

  static inline uint32_t rfx_bitstream_get_bits(RFX_BITSTREAM* bs, uint32_t nbits)

  {

    UINT16 n = 0;

    while (bs->byte_pos < bs->nbytes && nbits > 0)

    {

      uint32_t b = nbits;

      if (b > bs->bits_left)

        b = bs->bits_left;

      if (n)

        n <<= b;

      n |= (bs->buffer[bs->byte_pos] >> (bs->bits_left - b)) & ((1 << b) - 1);

      bs->bits_left -= b;

      nbits -= b;

      if (bs->bits_left == 0)

      {

        bs->bits_left = 8;

        bs->byte_pos++;

      }

    }

    return n;

  }

  static inline void rfx_bitstream_put_bits(RFX_BITSTREAM* bs, uint32_t _bits, uint32_t _nbits)

  {

    UINT16 bits = WINPR_ASSERTING_INT_CAST(UINT16, _bits);

    uint32_t nbits = (_nbits);

    while (bs->byte_pos < bs->nbytes && nbits > 0)

    {

      uint32_t b = nbits;

      if (b > bs->bits_left)

        b = bs->bits_left;

      bs->buffer[bs->byte_pos] |= ((bits >> (nbits - b)) & ((1 << b) - 1))

                                  << (bs->bits_left - b);

      bs->bits_left -= b;

      nbits -= b;

      if (bs->bits_left == 0)

      {

        bs->bits_left = 8;

        bs->byte_pos++;

      }

    }

  }

  static inline void rfx_bitstream_flush(RFX_BITSTREAM* bs)

  {

    WINPR_ASSERT(bs);

    if (bs->bits_left != 8)

    {

      uint32_t _nbits = 8 - bs->bits_left;

      rfx_bitstream_put_bits(bs, 0, _nbits);

    }

  }

  WINPR_ATTR_NODISCARD

  static inline BOOL rfx_bitstream_eos(RFX_BITSTREAM* bs)

  {

    WINPR_ASSERT(bs);

    return ((bs)->byte_pos >= (bs)->nbytes);

  }

  WINPR_ATTR_NODISCARD

  static inline uint32_t rfx_bitstream_left(RFX_BITSTREAM* bs)

  {

    WINPR_ASSERT(bs);

    if ((bs)->byte_pos >= (bs)->nbytes)

      return 0;

    return ((bs)->nbytes - (bs)->byte_pos - 1) * 8 + (bs)->bits_left;

  }

  WINPR_ATTR_NODISCARD

  static inline uint32_t rfx_bitstream_get_processed_bytes(RFX_BITSTREAM* bs)

  {

    WINPR_ASSERT(bs);

    if ((bs)->bits_left < 8)

      return (bs)->byte_pos + 1;

    return (bs)->byte_pos;

  }

#ifdef __cplusplus

}

#endif

#endif /* FREERDP_LIB_CODEC_RFX_BITSTREAM_H */