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/******************************************************************************
*
* Copyright (C) 2015 The Android Open Source Project
*
* 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.
*
*****************************************************************************
* Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/
/*****************************************************************************/
/* */
/* File Name : impeg2d_bitstream.h */
/* */
/* Description : This file contains all the necessary examples to */
/* establish a consistent use of Ittiam C coding */
/* standards (based on Indian Hill C Standards) */
/* */
/* List of Functions : <List the functions defined in this file> */
/* */
/* Issues / Problems : None */
/* */
/* Revision History : */
/* */
/* DD MM YYYY Author(s) Changes (Describe the changes made) */
/* 10 01 2005 Ittiam Draft */
/* */
/*****************************************************************************/
#ifndef __IMPEG2D_BITSTREAM_H__
#define __IMPEG2D_BITSTREAM_H__
/* Structure for the stream */
typedef struct _stream_t
{
void *pv_bs_buf; /* Pointer to buffer containing the
bitstream */
UWORD32 *pu4_buf_aligned; /* Pointer to the buffer after alignment correction,
It points to the currently usable buffer */
UWORD32 u4_offset; /* Offset in the buffer for the current bit */
UWORD32 u4_buf; /* Buffer storing the current word */
UWORD32 u4_buf_nxt; /* Buffer storing the next Word */
UWORD32 u4_max_offset; /* Max Bit stream buffer offset in bytes for error checks */
} stream_t;
#define GET_MARKER_BIT(dec,stream) \
{ \
if (impeg2d_bit_stream_get(stream,1) != 0x1) { \
/* No need to return error if marker is not present. */ \
} \
}
/* Define A macro for inlining of FlushBits */
#define FLUSH_BITS(u4_offset,u4_buf,u4_buf_nxt,u4_no_bits,pu4_buf_aligned) \
{ \
UWORD32 u4_temp; \
\
if (((u4_offset & 0x1f) + u4_no_bits)>= 32) \
{ \
u4_buf = u4_buf_nxt; \
\
u4_temp = *(pu4_buf_aligned)++; \
\
CONV_LE_TO_BE(u4_buf_nxt,u4_temp) \
} \
u4_offset += u4_no_bits; \
}
/* Macro to initialize the variables from stream */
#define GET_TEMP_STREAM_DATA(u4_buf,u4_buf_nxt,u4_offset,pu4_buf_aligned,stream) \
{ \
u4_buf = stream->u4_buf; \
u4_buf_nxt = stream->u4_buf_nxt; \
u4_offset = stream->u4_offset; \
pu4_buf_aligned = stream->pu4_buf_aligned; \
}
/* Macro to put the stream variable values back */
#define PUT_TEMP_STREAM_DATA(u4_buf,u4_buf_nxt,u4_offset,pu4_buf_aligned,stream) \
{ \
stream->u4_buf = u4_buf; \
stream->u4_buf_nxt = u4_buf_nxt; \
stream->u4_offset = u4_offset; \
stream->pu4_buf_aligned = pu4_buf_aligned; \
}
/* Macro to implement the get bits inline (ibits_nxt_inline) */
#define IBITS_NXT(u4_buf, u4_buf_nxt, u4_offset, u4_bits, no_of_bits) \
{ \
UWORD8 u4_bit_ptr; \
UWORD32 u4_temp; \
\
u4_bit_ptr = u4_offset & 0x1F; \
u4_bits = u4_buf << u4_bit_ptr; \
\
u4_bit_ptr += no_of_bits; \
\
if(32 < u4_bit_ptr) \
{ \
/* Read bits from the next word if necessary */ \
u4_temp = u4_buf_nxt; \
u4_bit_ptr &= (BITS_IN_INT - 1); \
\
u4_temp = (u4_temp >> (BITS_IN_INT - u4_bit_ptr)); \
\
/* u4_temp consists of bits,if any that had to be read from the next word*/ \
/* of the buffer.The bits read from both the words are concatenated and*/ \
/* moved to the least significant positions of 'u4_bits'*/ \
u4_bits = (u4_bits >> (32 - no_of_bits)) | u4_temp; \
} \
else \
{ \
u4_bits = (u4_bits >> (32 - no_of_bits)); \
} \
}
/* Macro to implement the get bits inline (ibits_get_inline) */
#define IBITS_GET(u4_buf,u4_buf_nxt,u4_offset,u4_bits,pu4_buf_aligned,no_of_bits) \
{ \
IBITS_NXT(u4_buf, u4_buf_nxt, u4_offset, u4_bits, no_of_bits) \
FLUSH_BITS(u4_offset,u4_buf,u4_buf_nxt,no_of_bits,pu4_buf_aligned) \
}
void impeg2d_bit_stream_init(stream_t *stream,
UWORD8 *byteBuf,
UWORD32 u4_max_offset);
INLINE UWORD8 impeg2d_bit_stream_get_bit(stream_t *stream);
INLINE void impeg2d_bit_stream_flush(void* ctxt, UWORD32 NoOfBits);
INLINE void impeg2d_bit_stream_flush_to_byte_boundary(void* ctxt);
INLINE UWORD32 impeg2d_bit_stream_nxt(stream_t *stream, WORD32 NoOfBits);
INLINE UWORD32 impeg2d_bit_stream_get(void* ctxt, UWORD32 numBits);
INLINE UWORD32 impeg2d_bit_stream_num_bits_read(void* ctxt);
#endif /* __IMPEG2D_BITSTREAM_H__ */
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