xref: /btstack/3rd-party/bluedroid/decoder/include/oi_bitstream.h (revision df25739fc3ea5a0a90f0f5925e6461d653697d2e)

/******************************************************************************
 *
 *  Copyright (C) 2014 The Android Open Source Project
 *  Copyright 2003 - 2004 Open Interface North America, Inc. All rights reserved.
 *
 *  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 _OI_BITSTREAM_H
#define _OI_BITSTREAM_H

/**********************************************************************************
  $Revision: #1 $
***********************************************************************************/


/**
@file
Function prototypes and macro definitions for manipulating input and output
bitstreams.

@ingroup codec_internal
*/

/**
@addtogroup codec_internal
@{
*/

#include "oi_codec_sbc_private.h"
#include "oi_stddefs.h"

INLINE void OI_BITSTREAM_ReadInit(OI_BITSTREAM *bs, const OI_BYTE *buffer);

INLINE void OI_BITSTREAM_WriteInit(OI_BITSTREAM *bs, OI_BYTE *buffer);

INLINE OI_UINT32 OI_BITSTREAM_ReadUINT(OI_BITSTREAM *bs, OI_UINT bits);

INLINE OI_UINT8 OI_BITSTREAM_ReadUINT4Aligned(OI_BITSTREAM *bs);

INLINE OI_UINT8 OI_BITSTREAM_ReadUINT8Aligned(OI_BITSTREAM *bs);

INLINE void OI_BITSTREAM_WriteUINT(OI_BITSTREAM *bs,
                                   OI_UINT16 value,
                                   OI_UINT bits);

/*
 * Use knowledge that the bitstream is aligned to optimize the write of a byte
 */
PRIVATE void OI_BITSTREAM_WriteUINT8Aligned(OI_BITSTREAM *bs,
                                            OI_UINT8 datum);

/*
 * Use knowledge that the bitstream is aligned to optimize the write pair of nibbles
 */
PRIVATE void OI_BITSTREAM_Write2xUINT4Aligned(OI_BITSTREAM *bs,
                                              OI_UINT8 datum1,
                                              OI_UINT8 datum2);

/** Internally the bitstream looks ahead in the stream. When
 * OI_SBC_ReadScalefactors() goes to temporarily break the abstraction, it will
 * need to know where the "logical" pointer is in the stream.
 */
#define OI_BITSTREAM_GetWritePtr(bs) ((bs)->ptr.w - 3)
#define OI_BITSTREAM_GetReadPtr(bs) ((bs)->ptr.r - 3)

/** This is declared here as a macro because decoder.c breaks the bitsream
 * encapsulation for efficiency reasons.
 */
#define OI_BITSTREAM_READUINT(result, bits, ptr, value, bitPtr) \
do { \
    OI_ASSERT((bits) <= 16); \
    OI_ASSERT((bitPtr) < 16); \
    OI_ASSERT((bitPtr) >= 8); \
    \
    result = (value) << (bitPtr); \
    result >>= 32 - (bits); \
    \
    bitPtr += (bits); \
    while (bitPtr >= 16) { \
        value = (((value) << 8) | *ptr++) & 0xffffffff; \
        bitPtr -= 8; \
    } \
    OI_ASSERT((bits == 0) || (result < (1u << (bits)))); \
} while (0)


#define OI_BITSTREAM_WRITEUINT(ptr, value, bitPtr, datum, bits) \
do {\
    bitPtr -= bits;\
    value |= datum << bitPtr;\
    \
    while (bitPtr <= 16) {\
        bitPtr += 8;\
        *ptr++ = (OI_UINT8)(value >> 24);\
        value <<= 8;\
    }\
} while (0)

#define OI_BITSTREAM_WRITEFLUSH(ptr, value, bitPtr) \
do {\
    while (bitPtr < 32) {\
        bitPtr += 8;\
        *ptr++ = (OI_UINT8)(value >> 24);\
        value <<= 8;\
    }\
} while (0)

/**
@}
*/

#endif /* _OI_BITSTREAM_H */