1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "M4OSA_Types.h" 18#include "M4OSA_Debug.h" 19 20#include "M4VD_Tools.h" 21 22/** 23 ************************************************************************ 24 * @file M4VD_Tools.c 25 * @brief 26 * @note This file implements helper functions for Bitstream parser 27 ************************************************************************ 28 */ 29 30M4OSA_UInt32 M4VD_Tools_GetBitsFromMemory(M4VS_Bitstream_ctxt* parsingCtxt, 31 M4OSA_UInt32 nb_bits) 32{ 33 M4OSA_UInt32 code; 34 M4OSA_UInt32 i; 35 code = 0; 36 for (i = 0; i < nb_bits; i++) 37 { 38 if (parsingCtxt->stream_index == 8) 39 { 40 //M4OSA_memcpy( (M4OSA_MemAddr8)&(parsingCtxt->stream_byte), parsingCtxt->in, 41 // sizeof(unsigned char)); 42 parsingCtxt->stream_byte = (unsigned char)(parsingCtxt->in)[0]; 43 parsingCtxt->in++; 44 //fread(&stream_byte, sizeof(unsigned char),1,in); 45 parsingCtxt->stream_index = 0; 46 } 47 code = (code << 1); 48 code |= ((parsingCtxt->stream_byte & 0x80) >> 7); 49 50 parsingCtxt->stream_byte = (parsingCtxt->stream_byte << 1); 51 parsingCtxt->stream_index++; 52 } 53 54 return code; 55} 56 57M4OSA_ERR M4VD_Tools_WriteBitsToMemory(M4OSA_UInt32 bitsToWrite, 58 M4OSA_MemAddr32 dest_bits, 59 M4OSA_UInt8 offset, M4OSA_UInt8 nb_bits) 60{ 61 M4OSA_UInt8 i,j; 62 M4OSA_UInt32 temp_dest = 0, mask = 0, temp = 1; 63 M4OSA_UInt32 input = bitsToWrite; 64 input = (input << (32 - nb_bits - offset)); 65 66 /* Put destination buffer to 0 */ 67 for(j=0;j<3;j++) 68 { 69 for(i=0;i<8;i++) 70 { 71 if((j*8)+i >= offset && (j*8)+i < nb_bits + offset) 72 { 73 mask |= (temp << ((7*(j+1))-i+j)); 74 } 75 } 76 } 77 mask = ~mask; 78 *dest_bits &= mask; 79 80 /* Parse input bits, and fill output buffer */ 81 for(j=0;j<3;j++) 82 { 83 for(i=0;i<8;i++) 84 { 85 if((j*8)+i >= offset && (j*8)+i < nb_bits + offset) 86 { 87 temp = ((input & (0x80000000 >> offset)) >> (31-offset)); 88 //*dest_bits |= (temp << (31 - i)); 89 *dest_bits |= (temp << ((7*(j+1))-i+j)); 90 input = (input << 1); 91 } 92 } 93 } 94 95 return M4NO_ERROR; 96} 97 98 99 100