vdr
1.7.27
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00001 /********************************************************************** 00002 * 00003 * HDFF firmware command interface library 00004 * 00005 * Copyright (C) 2011 Andreas Regel 00006 * 00007 * This program is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU General Public License 00009 * as published by the Free Software Foundation; either version 2 00010 * of the License, or (at your option) any later version. 00011 00012 * This program is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 * GNU General Public License for more details. 00016 00017 * You should have received a copy of the GNU General Public License 00018 * along with this program; if not, write to the 00019 * Free Software Foundation, Inc., 00020 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 00021 * 00022 *********************************************************************/ 00023 00024 #include <string.h> 00025 00026 #include "bitbuffer.h" 00027 00028 void BitBuffer_Init(BitBuffer_t * BitBuffer, 00029 uint8_t * Data, uint32_t MaxLength) 00030 { 00031 memset(Data, 0, MaxLength); 00032 BitBuffer->Data = Data; 00033 BitBuffer->MaxLength = MaxLength * 8; 00034 BitBuffer->BitPos = 0; 00035 } 00036 00037 void BitBuffer_SetBits(BitBuffer_t * BitBuffer, int NumBits, uint32_t Data) 00038 { 00039 uint32_t nextBitPos; 00040 uint32_t bytePos; 00041 uint32_t bitsInByte; 00042 int shift; 00043 00044 if (NumBits <= 0 || NumBits > 32) 00045 return; 00046 00047 nextBitPos = BitBuffer->BitPos + NumBits; 00048 00049 if (nextBitPos > BitBuffer->MaxLength) 00050 return; 00051 00052 bytePos = BitBuffer->BitPos / 8; 00053 bitsInByte = BitBuffer->BitPos % 8; 00054 00055 BitBuffer->Data[bytePos] &= (uint8_t) (0xFF << (8 - bitsInByte)); 00056 shift = NumBits - (8 - bitsInByte); 00057 if (shift > 0) 00058 BitBuffer->Data[bytePos] |= (uint8_t) (Data >> shift); 00059 else 00060 BitBuffer->Data[bytePos] |= (uint8_t) (Data << (-shift)); 00061 NumBits -= 8 - bitsInByte; 00062 bytePos++; 00063 while (NumBits > 0) 00064 { 00065 shift = NumBits - 8; 00066 if (shift > 0) 00067 BitBuffer->Data[bytePos] = (uint8_t) (Data >> shift); 00068 else 00069 BitBuffer->Data[bytePos] = (uint8_t) (Data << (-shift)); 00070 NumBits -= 8; 00071 bytePos++; 00072 } 00073 BitBuffer->BitPos = nextBitPos; 00074 } 00075 00076 uint32_t BitBuffer_GetByteLength(BitBuffer_t * BitBuffer) 00077 { 00078 return (BitBuffer->BitPos + 7) / 8; 00079 }