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BitMap Class Reference

#include <bitmap.h>

List of all members.

Public Methods

 BitMap (int nitems)
 ~BitMap ()
void Mark (int which)
void Clear (int which)
bool Test (int which)
int Find ()
int NumClear ()
void Print ()
void FetchFrom (OpenFile *file)
void WriteBack (OpenFile *file)

Private Attributes

int numBits
int numWords
unsigned int * map

Constructor & Destructor Documentation

BitMap::BitMap (  int    nitems ) 
 

Definition at line 20 of file bitmap.cc.

References BitsInWord, Clear, divRoundUp, map, numBits, and numWords. 

00021 { 
00022     numBits = nitems;
00023     numWords = divRoundUp(numBits, BitsInWord);
00024     map = new unsigned int[numWords];
00025     for (int i = 0; i < numBits; i++) 
00026         Clear(i);
00027 }

BitMap::~BitMap (    ) 
 

Definition at line 34 of file bitmap.cc.

References map. 

00035 { 
00036     delete map;
00037 }

Member Function Documentation

void BitMap::Clear (  int    which ) 
 

Definition at line 61 of file bitmap.cc.

References ASSERT, BitsInWord, map, and numBits.

Referenced by BitMap, FileHeader::Deallocate, and FileSystem::Remove. 

00062 {
00063     ASSERT(which >= 0 && which < numBits);
00064     map[which / BitsInWord] &= ~(1 << (which % BitsInWord));
00065 }

void BitMap::FetchFrom (  OpenFile *    file ) 
 

Definition at line 149 of file bitmap.cc.

References map, numWords, and OpenFile::ReadAt.

Referenced by FileSystem::Create, FileSystem::Print, and FileSystem::Remove. 

00150 {
00151     file->ReadAt((char *)map, numWords * sizeof(unsigned), 0);
00152 }

int BitMap::Find (    ) 
 

Definition at line 95 of file bitmap.cc.

References Mark, numBits, and Test.

Referenced by FileHeader::Allocate, and FileSystem::Create. 

00096 {
00097     for (int i = 0; i < numBits; i++)
00098         if (!Test(i)) {
00099             Mark(i);
00100             return i;
00101         }
00102     return -1;
00103 }

void BitMap::Mark (  int    which ) 
 

Definition at line 47 of file bitmap.cc.

References ASSERT, BitsInWord, map, and numBits.

Referenced by FileSystem::FileSystem, and Find. 

00048 { 
00049     ASSERT(which >= 0 && which < numBits);
00050     map[which / BitsInWord] |= 1 << (which % BitsInWord);
00051 }

int BitMap::NumClear (    ) 
 

Definition at line 112 of file bitmap.cc.

References numBits, and Test.

Referenced by FileHeader::Allocate. 

00113 {
00114     int count = 0;
00115 
00116     for (int i = 0; i < numBits; i++)
00117         if (!Test(i)) count++;
00118     return count;
00119 }

void BitMap::Print (    ) 
 

Definition at line 130 of file bitmap.cc.

References numBits, and Test.

Referenced by FileSystem::FileSystem, and FileSystem::Print. 

00131 {
00132     printf("Bitmap set:\n"); 
00133     for (int i = 0; i < numBits; i++)
00134         if (Test(i))
00135             printf("%d, ", i);
00136     printf("\n"); 
00137 }

bool BitMap::Test (  int    which ) 
 

Definition at line 75 of file bitmap.cc.

References ASSERT, BitsInWord, FALSE, map, numBits, and TRUE.

Referenced by FileHeader::Deallocate, Find, NumClear, and Print. 

00076 {
00077     ASSERT(which >= 0 && which < numBits);
00078     
00079     if (map[which / BitsInWord] & (1 << (which % BitsInWord)))
00080         return TRUE;
00081     else
00082         return FALSE;
00083 }

void BitMap::WriteBack (  OpenFile *    file ) 
 

Definition at line 162 of file bitmap.cc.

References map, numWords, and OpenFile::WriteAt.

Referenced by FileSystem::Create, FileSystem::FileSystem, and FileSystem::Remove. 

00163 {
00164    file->WriteAt((char *)map, numWords * sizeof(unsigned), 0);
00165 }

Member Data Documentation

unsigned int* BitMap::map [private]
 

Definition at line 61 of file bitmap.h.

Referenced by BitMap, Clear, FetchFrom, Mark, Test, WriteBack, and ~BitMap.

int BitMap::numBits [private]
 

Definition at line 56 of file bitmap.h.

Referenced by BitMap, Clear, Find, Mark, NumClear, Print, and Test.

int BitMap::numWords [private]
 

Definition at line 57 of file bitmap.h.

Referenced by BitMap, FetchFrom, and WriteBack.

The documentation for this class was generated from the following files:
Generated on Mon Feb 10 09:54:53 2003 for nachos by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002
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