/****************************************************************************** * * 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 : */ /* */ /* 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__ */