1 /****************************************************************************** 2 * 3 * Copyright (C) 2015 The Android Open Source Project 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ***************************************************************************** 18 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore 19 */ 20 /*****************************************************************************/ 21 /* */ 22 /* File Name : impeg2d_bitstream.h */ 23 /* */ 24 /* Description : This file contains all the necessary examples to */ 25 /* establish a consistent use of Ittiam C coding */ 26 /* standards (based on Indian Hill C Standards) */ 27 /* */ 28 /* List of Functions : <List the functions defined in this file> */ 29 /* */ 30 /* Issues / Problems : None */ 31 /* */ 32 /* Revision History : */ 33 /* */ 34 /* DD MM YYYY Author(s) Changes (Describe the changes made) */ 35 /* 10 01 2005 Ittiam Draft */ 36 /* */ 37 /*****************************************************************************/ 38 #ifndef __IMPEG2D_BITSTREAM_H__ 39 #define __IMPEG2D_BITSTREAM_H__ 40 41 42 43 /* Structure for the stream */ 44 typedef struct _stream_t 45 { 46 void *pv_bs_buf; /* Pointer to buffer containing the 47 bitstream */ 48 49 UWORD32 *pu4_buf_aligned; /* Pointer to the buffer after alignment correction, 50 It points to the currently usable buffer */ 51 52 UWORD32 u4_offset; /* Offset in the buffer for the current bit */ 53 54 UWORD32 u4_buf; /* Buffer storing the current word */ 55 56 UWORD32 u4_buf_nxt; /* Buffer storing the next Word */ 57 58 UWORD32 u4_max_offset; /* Max Bit stream buffer offset in bytes for error checks */ 59 } stream_t; 60 61 #define GET_MARKER_BIT(dec,stream) \ 62 { \ 63 if (impeg2d_bit_stream_get(stream,1) != 0x1) { \ 64 /* No need to return error if marker is not present. */ \ 65 } \ 66 } 67 68 /* Define A macro for inlining of FlushBits */ 69 #define FLUSH_BITS(u4_offset,u4_buf,u4_buf_nxt,u4_no_bits,pu4_buf_aligned) \ 70 { \ 71 UWORD32 u4_temp; \ 72 \ 73 if (((u4_offset & 0x1f) + u4_no_bits)>= 32) \ 74 { \ 75 u4_buf = u4_buf_nxt; \ 76 \ 77 u4_temp = *(pu4_buf_aligned)++; \ 78 \ 79 CONV_LE_TO_BE(u4_buf_nxt,u4_temp) \ 80 } \ 81 u4_offset += u4_no_bits; \ 82 } 83 84 /* Macro to initialize the variables from stream */ 85 #define GET_TEMP_STREAM_DATA(u4_buf,u4_buf_nxt,u4_offset,pu4_buf_aligned,stream) \ 86 { \ 87 u4_buf = stream->u4_buf; \ 88 u4_buf_nxt = stream->u4_buf_nxt; \ 89 u4_offset = stream->u4_offset; \ 90 pu4_buf_aligned = stream->pu4_buf_aligned; \ 91 } 92 93 /* Macro to put the stream variable values back */ 94 #define PUT_TEMP_STREAM_DATA(u4_buf,u4_buf_nxt,u4_offset,pu4_buf_aligned,stream) \ 95 { \ 96 stream->u4_buf = u4_buf; \ 97 stream->u4_buf_nxt = u4_buf_nxt; \ 98 stream->u4_offset = u4_offset; \ 99 stream->pu4_buf_aligned = pu4_buf_aligned; \ 100 } 101 102 /* Macro to implement the get bits inline (ibits_nxt_inline) */ 103 #define IBITS_NXT(u4_buf, u4_buf_nxt, u4_offset, u4_bits, no_of_bits) \ 104 { \ 105 UWORD8 u4_bit_ptr; \ 106 UWORD32 u4_temp; \ 107 \ 108 u4_bit_ptr = u4_offset & 0x1F; \ 109 u4_bits = u4_buf << u4_bit_ptr; \ 110 \ 111 u4_bit_ptr += no_of_bits; \ 112 \ 113 if(32 < u4_bit_ptr) \ 114 { \ 115 /* Read bits from the next word if necessary */ \ 116 u4_temp = u4_buf_nxt; \ 117 u4_bit_ptr &= (BITS_IN_INT - 1); \ 118 \ 119 u4_temp = (u4_temp >> (BITS_IN_INT - u4_bit_ptr)); \ 120 \ 121 /* u4_temp consists of bits,if any that had to be read from the next word*/ \ 122 /* of the buffer.The bits read from both the words are concatenated and*/ \ 123 /* moved to the least significant positions of 'u4_bits'*/ \ 124 u4_bits = (u4_bits >> (32 - no_of_bits)) | u4_temp; \ 125 } \ 126 else \ 127 { \ 128 u4_bits = (u4_bits >> (32 - no_of_bits)); \ 129 } \ 130 } 131 132 /* Macro to implement the get bits inline (ibits_get_inline) */ 133 #define IBITS_GET(u4_buf,u4_buf_nxt,u4_offset,u4_bits,pu4_buf_aligned,no_of_bits) \ 134 { \ 135 IBITS_NXT(u4_buf, u4_buf_nxt, u4_offset, u4_bits, no_of_bits) \ 136 FLUSH_BITS(u4_offset,u4_buf,u4_buf_nxt,no_of_bits,pu4_buf_aligned) \ 137 } 138 139 void impeg2d_bit_stream_init(stream_t *stream, 140 UWORD8 *byteBuf, 141 UWORD32 u4_max_offset); 142 INLINE UWORD8 impeg2d_bit_stream_get_bit(stream_t *stream); 143 INLINE void impeg2d_bit_stream_flush(void* ctxt, UWORD32 NoOfBits); 144 INLINE void impeg2d_bit_stream_flush_to_byte_boundary(void* ctxt); 145 INLINE UWORD32 impeg2d_bit_stream_nxt(stream_t *stream, WORD32 NoOfBits); 146 147 INLINE UWORD32 impeg2d_bit_stream_get(void* ctxt, UWORD32 numBits); 148 INLINE UWORD32 impeg2d_bit_stream_num_bits_read(void* ctxt); 149 150 151 152 153 154 155 156 #endif /* __IMPEG2D_BITSTREAM_H__ */ 157
