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680165d7 | 1 | //-*- Mode: C++ -*- |
2 | // $Id$ | |
3 | #ifndef ALIHLTDATAINFLATER_H | |
4 | #define ALIHLTDATAINFLATER_H | |
5 | //* This file is property of and copyright by the ALICE HLT Project * | |
6 | //* ALICE Experiment at CERN, All rights reserved. * | |
7 | //* See cxx source for full Copyright notice * | |
8 | ||
9 | /// @file AliHLTDataInflater.h | |
10 | /// @author Matthias Richter, Timm Steinbeck | |
11 | /// @date 2011-08-10 | |
12 | /// @brief Data inflater reading the bitstream from the AliHLTDataDeflater | |
13 | /// @note Code original from AliHLTTPCCompModelInflater | |
14 | ||
15 | #include "AliHLTLogging.h" | |
16 | #include "AliHLTDataTypes.h" | |
17 | #include "AliHLTStdIncludes.h" | |
18 | ||
19 | /** | |
20 | * @class AliHLTDataInflater | |
6bd50951 | 21 | * Data inflating interface to a bitstream encoded by AliHLTDataDeflater |
22 | * | |
23 | * Setting up the data inflater: | |
24 | * <pre> | |
25 | AliHLTDataInflater inflater; | |
26 | if (inflater.InitBitDataInput(pData, dataSize)<0) { | |
27 | // can not initialize | |
28 | } | |
29 | * </pre> | |
30 | * | |
31 | * If the layout in the bitstream is known the parts of known bit length | |
32 | * can be read by | |
33 | * - InputBit(value) | |
34 | * - InputBits(value, length) | |
35 | * | |
36 | * For inflating huffman encoded streams where the symbol length is unknown | |
37 | * one has to read a fixed value, retrieve the symbol and rewind the stream. | |
38 | * Example how to read a fixed number of bits from the stream and rewind | |
39 | * after the length of the symbol has been determined. | |
40 | * <pre> | |
41 | AliHLTUInt64_t inputWord=0; | |
42 | int inputLength=sizeof(inputWord)*8; | |
43 | while (outClusterCnt<nofClusters && inflater.InputBits(inputWord, inputLength)) { | |
44 | // check how many of the bits belong to the symbol and rewind the | |
45 | // input stream | |
46 | int symbolLength=...; | |
47 | inputWord>>=(inputLength-symbolLength); | |
48 | if (!inflater.RewindBitPosition(inputLength-symbolLength)) { | |
49 | // some error | |
50 | break; | |
51 | } | |
52 | ||
53 | // do something with data in input word | |
54 | ||
55 | // check if there is less remaining data than the full input word bit length | |
56 | UInt_t bytes=inflater.GetRemainingBitDataSizeBytes(); | |
57 | if (bytes>0 && bytes<=sizeof(inputWord)) { | |
58 | // reading the last bytes | |
59 | // available bits are determined by cuurent position+1 (because | |
60 | // position 0 means 1 bit still available) and the bits in the | |
61 | // available bytes | |
62 | inputLength=inflater.GetCurrentBitInputPosition()+1+(bytes-1)*8; | |
63 | } | |
64 | } | |
65 | * </pre> | |
680165d7 | 66 | * |
67 | * | |
68 | * @ingroup alihlt_base | |
69 | */ | |
70 | class AliHLTDataInflater : public AliHLTLogging | |
71 | { | |
72 | public: | |
73 | /// standard constructor | |
74 | AliHLTDataInflater(); | |
75 | /// destructor | |
76 | ~AliHLTDataInflater(); | |
77 | ||
78 | /** init inflater for reading | |
79 | * @param input AliHLTUInt8_t* pointer to input data | |
80 | * @param inputSize UInt_t input data size | |
81 | */ | |
82 | int InitBitDataInput(const AliHLTUInt8_t* input, UInt_t inputSize ); | |
83 | ||
84 | /** close inflater for reading */ | |
85 | void CloseBitDataInput(); | |
86 | ||
87 | /** function to get current byte input position | |
88 | * @return unsigned long value of current byte input position | |
89 | */ | |
90 | unsigned long GetCurrentByteInputPosition() const | |
91 | { | |
92 | return (unsigned long)( fBitDataCurrentInput - fBitDataCurrentInputStart ); | |
93 | } | |
94 | ||
95 | /** function to get current bit input position | |
96 | * @return unsigned value of current bit input position | |
97 | */ | |
98 | unsigned GetCurrentBitInputPosition() const | |
99 | { | |
100 | return fBitDataCurrentPosInWord; | |
101 | } | |
102 | ||
103 | /** function to get current input byte | |
104 | * @return AliHLTUInt8_t value of current input byte | |
105 | */ | |
106 | AliHLTUInt8_t GetCurrentInputByte() const | |
107 | { | |
108 | return fBitDataCurrentWord; | |
109 | } | |
110 | ||
111 | /** function to determine end of bit input | |
112 | * @return boolean if end is reached or not | |
113 | */ | |
114 | bool EndOfBitInput() const | |
115 | { | |
116 | return (fBitDataCurrentInput>=fBitDataCurrentInputEnd); | |
117 | } | |
118 | ||
119 | /** function to get bit data input size bytes | |
120 | * @return UInt_t value of bit data input size bytes | |
121 | */ | |
122 | UInt_t GetBitDataInputSizeBytes() const | |
123 | { | |
124 | return fBitDataCurrentInput-fBitDataCurrentInputStart; | |
125 | } | |
126 | ||
6bd50951 | 127 | /** get number of remaining input bytes |
128 | * the last byte might be already partially read, use | |
129 | * GetCurrentBitInputPosition() | |
130 | */ | |
131 | UInt_t GetRemainingBitDataSizeBytes() const | |
132 | { | |
133 | return fBitDataCurrentInputEnd-fBitDataCurrentInput; | |
134 | } | |
135 | ||
680165d7 | 136 | /** function to determine input bit |
137 | * @return boolean (if bit is 1 or 0) | |
138 | */ | |
139 | bool InputBit( AliHLTUInt8_t & value ); | |
140 | ||
141 | /** function to read bits from bitstream | |
142 | * @param value | |
143 | * @param bitCount | |
144 | * @return boolean | |
145 | */ | |
146 | template<typename T> | |
147 | bool InputBits( T & value, UInt_t const & bitCount ); | |
6bd50951 | 148 | |
149 | /** | |
150 | * Rewind the current bit position by the given number of bits. | |
151 | */ | |
152 | bool RewindBitPosition(UInt_t const & bitCount); | |
680165d7 | 153 | |
154 | /** function pad 8 bits */ | |
155 | void Pad8Bits(); | |
156 | ||
157 | /** function to determine input bytes | |
158 | * @param data AliHLTUInt8_t* pointer to input data | |
159 | * @param byteCount UInt_t const & | |
160 | * @return boolean | |
161 | */ | |
162 | bool InputBytes( AliHLTUInt8_t* data, UInt_t const & byteCount ); | |
163 | ||
9409b4b1 | 164 | /** |
165 | * Read the next value. | |
166 | * Data read function for inflaters for different formats | |
167 | */ | |
168 | virtual bool NextValue(AliHLTUInt64_t& /*value*/, AliHLTUInt32_t& /*length*/) {return false;} | |
70d61ae2 | 169 | /// switch to next parameter |
170 | virtual int NextParameter() {return -ENOSYS;} | |
9409b4b1 | 171 | |
680165d7 | 172 | /// clear the object and reset pointer references |
173 | virtual void Clear(Option_t * /*option*/ =""); | |
174 | ||
175 | /// print info | |
176 | virtual void Print(Option_t *option="") const; | |
177 | ||
178 | /// print info | |
179 | virtual void Print(ostream& out, Option_t *option="") const; | |
180 | ||
181 | protected: | |
182 | private: | |
183 | /** copy constructor prohibited */ | |
184 | AliHLTDataInflater(const AliHLTDataInflater&); | |
185 | /** assignment operator prohibited */ | |
186 | AliHLTDataInflater& operator=(const AliHLTDataInflater&); | |
187 | ||
188 | /** member variable for bit data current word */ | |
189 | AliHLTUInt8_t fBitDataCurrentWord; // member variable for bit data current word | |
190 | /** member variable for bit data current position in word */ | |
191 | UInt_t fBitDataCurrentPosInWord;// member variable for bit data current position in word | |
192 | /** member variable for bit data current input */ | |
193 | const AliHLTUInt8_t *fBitDataCurrentInput; // member variable for bit data current input | |
194 | /** member variable for bit data current input start */ | |
195 | const AliHLTUInt8_t *fBitDataCurrentInputStart; // member variable for bit data current input star | |
196 | /** member variable for bit data current input end */ | |
197 | const AliHLTUInt8_t *fBitDataCurrentInputEnd; // member variable for bit data current input end | |
198 | ||
199 | ClassDef(AliHLTDataInflater, 0) | |
200 | }; | |
201 | ||
202 | template<typename T> | |
203 | bool AliHLTDataInflater::InputBits( T & value, UInt_t const & bitCount ) | |
204 | { | |
205 | // read bits from the input stream into variable | |
206 | if (bitCount>sizeof(T)*8) { | |
207 | HLTFatal( "variable of type size %u too small to read %u bits", sizeof(T)*8, (unsigned)bitCount); | |
208 | return false; | |
209 | } | |
210 | UInt_t bitsToRead=bitCount; | |
211 | UInt_t curBitCount; | |
212 | value = 0; | |
213 | while ( bitsToRead>0 ) { | |
214 | if ( fBitDataCurrentInput>=fBitDataCurrentInputEnd ) | |
215 | return false; | |
216 | if ( bitsToRead >= fBitDataCurrentPosInWord+1 ) | |
217 | curBitCount = fBitDataCurrentPosInWord+1; | |
218 | else | |
219 | curBitCount = bitsToRead; | |
220 | value = (value << curBitCount) | ( (fBitDataCurrentWord >> (fBitDataCurrentPosInWord-curBitCount+1)) & ((1 << curBitCount)-1) ); | |
221 | if ( fBitDataCurrentPosInWord < curBitCount ) { | |
222 | fBitDataCurrentInput++; | |
6bd50951 | 223 | fBitDataCurrentPosInWord = 7; |
680165d7 | 224 | if ( fBitDataCurrentInput<fBitDataCurrentInputEnd ) { |
225 | fBitDataCurrentWord = *fBitDataCurrentInput; | |
680165d7 | 226 | } |
227 | } | |
228 | else | |
229 | fBitDataCurrentPosInWord -= curBitCount; | |
230 | bitsToRead -= curBitCount; | |
231 | } | |
232 | return true; | |
233 | } | |
234 | ||
235 | ostream& operator<<(ostream &out, const AliHLTDataInflater& me); | |
236 | ||
237 | #endif |