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ISMIndex.h
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1//# ISMIndex.h: The Index of the Incremental Storage Manager
2//# Copyright (C) 1996,1997,1999,2005
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have received a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//# $Id$
27
28#ifndef TABLES_ISMINDEX_H
29#define TABLES_ISMINDEX_H
30
31//# Includes
32#include <casacore/casa/aips.h>
33#include <casacore/casa/Containers/Block.h>
34
35namespace casacore { //# NAMESPACE CASACORE - BEGIN
36
37//# Forward declarations
38class ISMBase;
39class AipsIO;
40
41
42// <summary>
43// The Index of the Incremental Storage Manager
44// </summary>
45
46// <use visibility=local>
47
48// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
49// </reviewed>
50
51// <prerequisite>
52//# Classes you should understand before using this one.
53// <li> <linkto class=ISMBase>ISMBase</linkto>
54// </prerequisite>
55
56// <etymology>
57// ISMIndex represents the index in the Incremental Storage Manager.
58// </etymology>
59
60// <synopsis>
61// ISMIndex maintains an index of all buckets in an ISM (Incremental Storage
62// Manager). The index consists of the starting row number and the
63// bucket number of each bucket in the BucketCache object of the ISM.
64// When the ISM is opened, the entire index is read in and kept in memory.
65// When the ISM is closed or flushed, the index is written back after
66// all buckets in the file. A little header at the beginning of the file
67// indicates the starting offset of the index.
68// </synopsis>
69
70// <motivation>
71// ISMIndex encapsulates all operations on the ISM index.
72// </motivation>
73
74//# <todo asof="$DATE:$">
75//# A List of bugs, limitations, extensions or planned refinements.
76//# </todo>
77
78
80{
81public:
82 // Create a ISMIndex object with the given parent for a new table.
83 // It keeps the pointer to its parent (but does not own it).
84 explicit ISMIndex (ISMBase* parent);
85
86 // The destructor closes the file (if opened).
88
89 // Add a row.
90 void addRow (rownr_t nrrow);
91
92 // Remove a row from the index.
93 // If the result of this is that the entire bucket gets empty,
94 // that bucketnr is returned. Otherwise -1 is returned.
96
97 // Get the bucket number for the given row.
98 // Also return the start row of the bucket and the number of rows in it.
99 uInt getBucketNr (rownr_t rownr, rownr_t& bucketStartRow,
100 rownr_t& bucketNrrow) const;
101
102 // Read the bucket index from the AipsIO object.
103 void get (AipsIO& os);
104
105 // Write the bucket index into the AipsIO object.
106 void put (AipsIO& os);
107
108 // Add a bucket number to the index.
109 // Argument <src>rownr</src> gives the starting row of the bucket.
110 // It is used to add the bucket number at the correct place
111 // (such that the row numbers are kept in ascending order).
112 void addBucketNr (rownr_t rownr, uInt bucketNr);
113
114 // Get the number of the next bucket from the index and return
115 // it in <src>bucketNr</src>. The starting row of that bucket and
116 // the number of rows in the bucket are also returned.
117 // Return status False indicates that no more buckets are available.
118 // <br>The start of the iteration is indicated by cursor=0.
119 // The first bucket returned is the bucket containing the rownr
120 // given in <src>bucketStartRow</src> (thus set bucketStartRow
121 // to 0 if you want to start at the first bucket).
122 // <br>The next iterations return the next bucket number and fill
123 // the starting row and number of rows.
124 Bool nextBucketNr (uInt& cursor, rownr_t& bucketStartRow,
125 rownr_t& bucketNrrow, uInt& bucketNr) const;
126
127 // Show the index.
128 void show (std::ostream&) const;
129
130private:
131 // Forbid copy constructor.
133
134 // Forbid assignment.
136
137 // Get the index of the bucket containing the given row.
138 uInt getIndex (rownr_t rownr) const;
139
140
141 //# Declare member variables.
142 // Pointer to the parent storage manager.
144 // Number of entries used.
146 // Rownr index (i.e. row rows_p[i] starts in bucketNr_p[i]).
148 // Corresponding bucket number.
150};
151
152
153
154
155} //# NAMESPACE CASACORE - END
156
157#endif
simple 1-D array
Definition Block.h:200
void get(AipsIO &os)
Read the bucket index from the AipsIO object.
uInt nused_p
Number of entries used.
Definition ISMIndex.h:145
void addBucketNr(rownr_t rownr, uInt bucketNr)
Add a bucket number to the index.
uInt getBucketNr(rownr_t rownr, rownr_t &bucketStartRow, rownr_t &bucketNrrow) const
Get the bucket number for the given row.
Int removeRow(rownr_t rownr)
Remove a row from the index.
ISMIndex(ISMBase *parent)
Create a ISMIndex object with the given parent for a new table.
uInt getIndex(rownr_t rownr) const
Get the index of the bucket containing the given row.
void show(std::ostream &) const
Show the index.
ISMIndex & operator=(const ISMIndex &)
Forbid assignment.
Block< rownr_t > rows_p
Rownr index (i.e.
Definition ISMIndex.h:147
void put(AipsIO &os)
Write the bucket index into the AipsIO object.
Block< uInt > bucketNr_p
Corresponding bucket number.
Definition ISMIndex.h:149
ISMBase * stmanPtr_p
Pointer to the parent storage manager.
Definition ISMIndex.h:143
void addRow(rownr_t nrrow)
Add a row.
~ISMIndex()
The destructor closes the file (if opened).
ISMIndex(const ISMIndex &)
Forbid copy constructor.
Bool nextBucketNr(uInt &cursor, rownr_t &bucketStartRow, rownr_t &bucketNrrow, uInt &bucketNr) const
Get the number of the next bucket from the index and return it in bucketNr.
this file contains all the compiler specific defines
Definition mainpage.dox:28
unsigned int uInt
Definition aipstype.h:51
int Int
Definition aipstype.h:50
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:42
uInt64 rownr_t
Define the type of a row number in a table.
Definition aipsxtype.h:46