146 lines
4.1 KiB
C++
146 lines
4.1 KiB
C++
//+-------------------------------------------------------------------------
|
|
//
|
|
// Microsoft Windows
|
|
// Copyright (C) Microsoft Corporation, 1992 - 1994
|
|
//
|
|
// File: KeyHash.cxx
|
|
//
|
|
// Contents: Key hash
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
// 29-May-1994 DwightKr Changed hash table to store bit
|
|
// offset of first key on page, rather
|
|
// than just the page number.
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
#include <pch.cxx>
|
|
#pragma hdrstop
|
|
|
|
#include "keyhash.hxx"
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CKeyHash::CKeyHash
|
|
//
|
|
// Synopsis: Construct keyhash
|
|
//
|
|
// Arguments: [cDirEntry] -- Number of leaf directory nodes
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CKeyHash::CKeyHash( unsigned cDirEntry )
|
|
: _cBitsPerEntry( Size(cDirEntry) )
|
|
{
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CRKeyHash::CRKeyHash
|
|
//
|
|
// Synopsis: Construct keyhash
|
|
//
|
|
// Arguments: [physHash] -- On disk stream
|
|
// [cDirEntry] -- Number of leaf directory nodes
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CRKeyHash::CRKeyHash( CPhysHash & physHash, unsigned cDirEntry )
|
|
: CKeyHash(cDirEntry),
|
|
_bitstm( physHash )
|
|
{
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CRKeyHash::Find
|
|
//
|
|
// Synopsis: Lookup value for key in hash
|
|
//
|
|
// Arguments: [kid] -- Key id
|
|
//
|
|
// Returns: Bitoffset for [kid]
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
void CRKeyHash::Find( KEYID kid, BitOffset & resultOffset )
|
|
{
|
|
BitOffset off = KidToOff(kid);
|
|
|
|
_bitstm.Seek( off );
|
|
|
|
ULONG ulResult = _bitstm.GetBits( BitsPerEntry() );
|
|
resultOffset.Init( ulResult >> BITS_IN_CI_PAGE_SIZE,
|
|
ulResult & CI_PAGE_MASK);
|
|
|
|
|
|
ciDebugOut(( DEB_KEYLIST, "KeyHash: kid %u --> page,off 0x%x,0x%x\n",
|
|
kid, resultOffset.Page(), resultOffset.Offset() ));
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CWKeyHash::CWKeyHash
|
|
//
|
|
// Synopsis: Construct keyhash
|
|
//
|
|
// Arguments: [physHash] -- On disk stream
|
|
// [cDirEntry] -- Number of leaf directory nodes
|
|
// [kidMax] -- Number of keys to be stored
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
CWKeyHash::CWKeyHash( CPhysHash & physHash, unsigned cDirEntry, KEYID kidMax )
|
|
: CKeyHash(cDirEntry),
|
|
_bitstm( physHash )
|
|
{
|
|
//
|
|
// Zero all pages by touching them.
|
|
//
|
|
|
|
BitOffset off = KidToOff(kidMax+1);
|
|
|
|
ciDebugOut(( DEB_KEYLIST, "KeyHash: Zeroing %d pages\n", off.Page() ));
|
|
|
|
for ( ULONG i = 0; i <= off.Page(); i++ )
|
|
{
|
|
physHash.BorrowNewBuffer( i );
|
|
physHash.ReturnBuffer( i );
|
|
}
|
|
}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CWKeyHash::Add
|
|
//
|
|
// Synopsis: Add mapping for new key
|
|
//
|
|
// Arguments: [kid] -- Key id
|
|
// [bitOff] -- Directory entry corresponding to [kid]
|
|
//
|
|
// History: 17-Feb-1994 KyleP Created
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
void CWKeyHash::Add( KEYID kid, BitOffset & bitOff )
|
|
{
|
|
BitOffset off = KidToOff(kid);
|
|
_bitstm.Seek( off );
|
|
|
|
Win4Assert(bitOff.Page() < 0x100000); // Fits into a 20-bit number
|
|
ULONG ulDirEntry = (bitOff.Page() << BITS_IN_CI_PAGE_SIZE ) | bitOff.Offset();
|
|
|
|
_bitstm.OverwriteBits( ulDirEntry, BitsPerEntry() );
|
|
|
|
ciDebugOut(( DEB_KEYLIST, "KeyHash: WRITE kid %u = page,offset 0x%x,0x%x\n",
|
|
kid, bitOff.Page(), bitOff.Offset() ));
|
|
}
|