1 #ifndef ALIHLTMUONDATABLOCKREADER_H
2 #define ALIHLTMUONDATABLOCKREADER_H
3 /**************************************************************************
4 * Copyright(c) 1998-2007, ALICE Experiment at CERN, All rights reserved. *
6 * Author: The ALICE Off-line Project. *
7 * Contributors are mentioned in the code where appropriate. *
9 * Permission to use, copy, modify and distribute this software and its *
10 * documentation strictly for non-commercial purposes is hereby granted *
11 * without fee, provided that the above copyright notice appears in all *
12 * copies and that both the copyright notice and this permission notice *
13 * appear in the supporting documentation. The authors make no claims *
14 * about the suitability of this software for any purpose. It is *
15 * provided "as is" without express or implied warranty. *
16 **************************************************************************/
21 * @file AliHLTMUONDataBlockReader.h
22 * @author Artur Szostak <artursz@iafrica.com>
24 * @brief Definition of a reader class for internal dimuon HLT raw data blocks.
27 #include "AliHLTMUONDataTypes.h"
30 #include "AliHLTMUONTriggerRecordsBlockStruct.h"
31 #include "AliHLTMUONTrigRecsDebugBlockStruct.h"
32 #include "AliHLTMUONTriggerChannelsBlockStruct.h"
33 #include "AliHLTMUONRecHitsBlockStruct.h"
34 #include "AliHLTMUONClustersBlockStruct.h"
35 #include "AliHLTMUONChannelsBlockStruct.h"
38 * A light weight class for reading the contents of an internal dimuon HLT
40 * Suppose we are given a pointer 'buffer' to the buffer where a data block is
41 * stored in memory and the size of the data block is given by the variable 'size'.
42 * The data block is of type 'block_type' and the data block entries are of type
43 * 'entries_type'. The data block can be accessed in the following way:
45 * void* buffer = somebuffer;
46 * AliHLTUInt32_t size = somebuffer_size;
48 * // Initialise the data block reader.
49 * AliHLTMUONDataBlockReader<block_type, entries_type> block(buffer, size);
51 * // Check that the buffer has the expected size.
52 * if (not block.BufferSizeOk())
57 * // Find the number of entries in the data block.
58 * AliHLTUInt32_t nentries = block.Nentries();
60 * // Loop over all entries in the data block.
61 * for (AliHLTUInt32_t i = 0; i < nentries; i++)
63 * const entries_type& entry = block[i];
64 * // Do something with the entry...
67 template <class DataBlockType, class DataElementType>
68 class AliHLTMUONDataBlockReader
73 * Constructor that sets the internal pointer to the start of the data
74 * block and the total size of the block in bytes.
75 * @param buffer The pointer to the first byte of the block in memory.
76 * @param size The total size of the data block in bytes.
78 AliHLTMUONDataBlockReader(const void* buffer, AliHLTUInt32_t size) :
80 fBlock(reinterpret_cast<const DataBlockType*>(buffer)),
81 fData(reinterpret_cast<const DataElementType*>(
82 reinterpret_cast<const DataBlockType*>(buffer) + 1
85 assert( buffer != NULL );
89 * Checks that the size of the buffer storing the data block is correct.
90 * Basic sanity checks are performed such as seeing if the data block
91 * size corresponds to the number of reconstructed hits stored and that
92 * the size of the buffer is at least sizeof(DataBlockType) bytes big.
94 bool BufferSizeOk() const
96 // The block size must be at least sizeof(DataBlockType) bytes.
97 if (fSize < sizeof(DataBlockType)) return false;
99 // Now check if the size of the data block corresponds to the
100 // number of entries it claims to contain.
101 AliHLTUInt32_t arraysize = fSize - sizeof(DataBlockType);
102 return arraysize == Nentries() * sizeof(DataElementType);
106 * Returns the common data block header.
108 const AliHLTMUONDataBlockHeader& BlockHeader() const
110 return fBlock->fHeader;
114 * Returns the total number of entries in the data block.
116 AliHLTUInt32_t Nentries() const { return fBlock->fHeader.fNrecords; }
119 * Returns a pointer to the i'th entry.
120 * If the index 'i' is out of bounds then NULL is returned.
121 * This is a safe access method because it does bounds checking but is
122 * a little slower than the array operator.
123 * @param i The index number of the entry to be returned.
124 * @return A pointer to the entry or NULL.
126 const DataElementType* Entry(AliHLTUInt32_t i) const
128 return (i < Nentries()) ? &fData[i] : NULL;
132 * Array operator for accessing the data entries directly.
133 * The index variable 'i' is not checked (except in debug compilations)
134 * so one should make sure they are within the valid range.
136 const DataElementType& operator [] (AliHLTUInt32_t i) const
138 assert( i < Nentries() );
143 * Returns a pointer to the array of elements in the data block.
144 * Care must be taken not to read beyond the array limits given by
147 const DataElementType* GetArray() const { return fData; }
151 AliHLTUInt32_t fSize; // Size of the data block in bytes.
152 const DataBlockType* fBlock; // Pointer to the data block buffer.
153 const DataElementType* fData; // Pointer to the data array.
157 // We now define the reader classes for the various data block types from the
158 // template class AliHLTMUONDataBlockReader.
160 typedef AliHLTMUONDataBlockReader<
161 AliHLTMUONTriggerRecordsBlockStruct,
162 AliHLTMUONTriggerRecordStruct
163 > AliHLTMUONTriggerRecordsBlockReader;
165 typedef AliHLTMUONDataBlockReader<
166 AliHLTMUONTrigRecsDebugBlockStruct,
167 AliHLTMUONTrigRecInfoStruct
168 > AliHLTMUONTrigRecsDebugBlockReader;
170 typedef AliHLTMUONDataBlockReader<
171 AliHLTMUONTriggerChannelsBlockStruct,
172 AliHLTMUONTriggerChannelStruct
173 > AliHLTMUONTriggerChannelsBlockReader;
175 typedef AliHLTMUONDataBlockReader<
176 AliHLTMUONRecHitsBlockStruct,
177 AliHLTMUONRecHitStruct
178 > AliHLTMUONRecHitsBlockReader;
180 typedef AliHLTMUONDataBlockReader<
181 AliHLTMUONClustersBlockStruct,
182 AliHLTMUONClusterStruct
183 > AliHLTMUONClustersBlockReader;
185 typedef AliHLTMUONDataBlockReader<
186 AliHLTMUONChannelsBlockStruct,
187 AliHLTMUONChannelStruct
188 > AliHLTMUONChannelsBlockReader;
190 #endif // ALIHLTMUONDATABLOCKREADER_H