wasCSharpSQLite – Rev 1
?pathlinks?
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using Pgno = System.UInt32;
using i64 = System.Int64;
using u32 = System.UInt32;
using BITVEC_TELEM = System.Byte;
namespace Community.CsharpSqlite
{
public partial class Sqlite3
{
/*
** 2008 February 16
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements an object that represents a fixed-length
** bitmap. Bits are numbered starting with 1.
**
** A bitmap is used to record which pages of a database file have been
** journalled during a transaction, or which pages have the "dont-write"
** property. Usually only a few pages are meet either condition.
** So the bitmap is usually sparse and has low cardinality.
** But sometimes (for example when during a DROP of a large table) most
** or all of the pages in a database can get journalled. In those cases,
** the bitmap becomes dense with high cardinality. The algorithm needs
** to handle both cases well.
**
** The size of the bitmap is fixed when the object is created.
**
** All bits are clear when the bitmap is created. Individual bits
** may be set or cleared one at a time.
**
** Test operations are about 100 times more common that set operations.
** Clear operations are exceedingly rare. There are usually between
** 5 and 500 set operations per Bitvec object, though the number of sets can
** sometimes grow into tens of thousands or larger. The size of the
** Bitvec object is the number of pages in the database file at the
** start of a transaction, and is thus usually less than a few thousand,
** but can be as large as 2 billion for a really big database.
*************************************************************************
** Included in SQLite3 port to C#-SQLite; 2008 Noah B Hart
** C#-SQLite is an independent reimplementation of the SQLite software library
**
** SQLITE_SOURCE_ID: 2010-08-23 18:52:01 42537b60566f288167f1b5864a5435986838e3a3
**
*************************************************************************
*/
//#include "sqliteInt.h"
/* Size of the Bitvec structure in bytes. */
static int BITVEC_SZ = 512;
/* Round the union size down to the nearest pointer boundary, since that's how
** it will be aligned within the Bitvec struct. */
//#define BITVEC_USIZE (((BITVEC_SZ-(3*sizeof(u32)))/sizeof(Bitvec*))*sizeof(Bitvec*))
static int BITVEC_USIZE = ( ( ( BITVEC_SZ - ( 3 * sizeof( u32 ) ) ) / 4 ) * 4 );
/* Type of the array "element" for the bitmap representation.
** Should be a power of 2, and ideally, evenly divide into BITVEC_USIZE.
** Setting this to the "natural word" size of your CPU may improve
** performance. */
//#define BITVEC_TELEM u8
//using BITVEC_TELEM = System.Byte;
/* Size, in bits, of the bitmap element. */
//#define BITVEC_SZELEM 8
const int BITVEC_SZELEM = 8;
/* Number of elements in a bitmap array. */
//#define BITVEC_NELEM (BITVEC_USIZE/sizeof(BITVEC_TELEM))
static int BITVEC_NELEM = (int)( BITVEC_USIZE / sizeof( BITVEC_TELEM ) );
/* Number of bits in the bitmap array. */
//#define BITVEC_NBIT (BITVEC_NELEM*BITVEC_SZELEM)
static int BITVEC_NBIT = ( BITVEC_NELEM * BITVEC_SZELEM );
/* Number of u32 values in hash table. */
//#define BITVEC_NINT (BITVEC_USIZE/sizeof(u32))
static u32 BITVEC_NINT = (u32)( BITVEC_USIZE / sizeof( u32 ) );
/* Maximum number of entries in hash table before
** sub-dividing and re-hashing. */
//#define BITVEC_MXHASH (BITVEC_NINT/2)
static int BITVEC_MXHASH = (int)( BITVEC_NINT / 2 );
/* Hashing function for the aHash representation.
** Empirical testing showed that the *37 multiplier
** (an arbitrary prime)in the hash function provided
** no fewer collisions than the no-op *1. */
//#define BITVEC_HASH(X) (((X)*1)%BITVEC_NINT)
static u32 BITVEC_HASH( u32 X )
{
return (u32)( ( ( X ) * 1 ) % BITVEC_NINT );
}
static int BITVEC_NPTR = (int)( BITVEC_USIZE / 4 );//sizeof(Bitvec *));
/*
** A bitmap is an instance of the following structure.
**
** This bitmap records the existence of zero or more bits
** with values between 1 and iSize, inclusive.
**
** There are three possible representations of the bitmap.
** If iSize<=BITVEC_NBIT, then Bitvec.u.aBitmap[] is a straight
** bitmap. The least significant bit is bit 1.
**
** If iSize>BITVEC_NBIT and iDivisor==0 then Bitvec.u.aHash[] is
** a hash table that will hold up to BITVEC_MXHASH distinct values.
**
** Otherwise, the value i is redirected into one of BITVEC_NPTR
** sub-bitmaps pointed to by Bitvec.u.apSub[]. Each subbitmap
** handles up to iDivisor separate values of i. apSub[0] holds
** values between 1 and iDivisor. apSub[1] holds values between
** iDivisor+1 and 2*iDivisor. apSub[N] holds values between
** N*iDivisor+1 and (N+1)*iDivisor. Each subbitmap is normalized
** to hold deal with values between 1 and iDivisor.
*/
public class _u
{
public BITVEC_TELEM[] aBitmap = new byte[BITVEC_NELEM]; /* Bitmap representation */
public u32[] aHash = new u32[BITVEC_NINT]; /* Hash table representation */
public Bitvec[] apSub = new Bitvec[BITVEC_NPTR]; /* Recursive representation */
}
public class Bitvec
{
public u32 iSize; /* Maximum bit index. Max iSize is 4,294,967,296. */
public u32 nSet; /* Number of bits that are set - only valid for aHash
** element. Max is BITVEC_NINT. For BITVEC_SZ of 512,
** this would be 125. */
public u32 iDivisor; /* Number of bits handled by each apSub[] entry. */
/* Should >=0 for apSub element. */
/* Max iDivisor is max(u32) / BITVEC_NPTR + 1. */
/* For a BITVEC_SZ of 512, this would be 34,359,739. */
public _u u = new _u();
public static implicit operator bool( Bitvec b )
{
return ( b != null );
}
};
/*
** Create a new bitmap object able to handle bits between 0 and iSize,
** inclusive. Return a pointer to the new object. Return NULL if
** malloc fails.
*/
static Bitvec sqlite3BitvecCreate( u32 iSize )
{
Bitvec p;
//Debug.Assert( sizeof(p)==BITVEC_SZ );
p = new Bitvec();//sqlite3MallocZero( sizeof(p) );
if ( p != null )
{
p.iSize = iSize;
}
return p;
}
/*
** Check to see if the i-th bit is set. Return true or false.
** If p is NULL (if the bitmap has not been created) or if
** i is out of range, then return false.
*/
static int sqlite3BitvecTest( Bitvec p, u32 i )
{
if ( p == null || i == 0 )
return 0;
if ( i > p.iSize )
return 0;
i--;
while ( p.iDivisor != 0 )
{
u32 bin = i / p.iDivisor;
i = i % p.iDivisor;
p = p.u.apSub[bin];
if ( null == p )
{
return 0;
}
}
if ( p.iSize <= BITVEC_NBIT )
{
return ( ( p.u.aBitmap[i / BITVEC_SZELEM] & ( 1 << (int)( i & ( BITVEC_SZELEM - 1 ) ) ) ) != 0 ) ? 1 : 0;
}
else
{
u32 h = BITVEC_HASH( i++ );
while ( p.u.aHash[h] != 0 )
{
if ( p.u.aHash[h] == i )
return 1;
h = ( h + 1 ) % BITVEC_NINT;
}
return 0;
}
}
/*
** Set the i-th bit. Return 0 on success and an error code if
** anything goes wrong.
**
** This routine might cause sub-bitmaps to be allocated. Failing
** to get the memory needed to hold the sub-bitmap is the only
** that can go wrong with an insert, assuming p and i are valid.
**
** The calling function must ensure that p is a valid Bitvec object
** and that the value for "i" is within range of the Bitvec object.
** Otherwise the behavior is undefined.
*/
static int sqlite3BitvecSet( Bitvec p, u32 i )
{
u32 h;
if ( p == null )
return SQLITE_OK;
Debug.Assert( i > 0 );
Debug.Assert( i <= p.iSize );
i--;
while ( ( p.iSize > BITVEC_NBIT ) && p.iDivisor != 0 )
{
u32 bin = i / p.iDivisor;
i = i % p.iDivisor;
if ( p.u.apSub[bin] == null )
{
p.u.apSub[bin] = sqlite3BitvecCreate( p.iDivisor );
//if ( p.u.apSub[bin] == null )
// return SQLITE_NOMEM;
}
p = p.u.apSub[bin];
}
if ( p.iSize <= BITVEC_NBIT )
{
p.u.aBitmap[i / BITVEC_SZELEM] |= (byte)( 1 << (int)( i & ( BITVEC_SZELEM - 1 ) ) );
return SQLITE_OK;
}
h = BITVEC_HASH( i++ );
/* if there wasn't a hash collision, and this doesn't */
/* completely fill the hash, then just add it without */
/* worring about sub-dividing and re-hashing. */
if ( 0 == p.u.aHash[h] )
{
if ( p.nSet < ( BITVEC_NINT - 1 ) )
{
goto bitvec_set_end;
}
else
{
goto bitvec_set_rehash;
}
}
/* there was a collision, check to see if it's already */
/* in hash, if not, try to find a spot for it */
do
{
if ( p.u.aHash[h] == i )
return SQLITE_OK;
h++;
if ( h >= BITVEC_NINT )
h = 0;
} while ( p.u.aHash[h] != 0 );
/* we didn't find it in the hash. h points to the first */
/* available free spot. check to see if this is going to */
/* make our hash too "full". */
bitvec_set_rehash:
if ( p.nSet >= BITVEC_MXHASH )
{
u32 j;
int rc;
u32[] aiValues = new u32[BITVEC_NINT];// = sqlite3StackAllocRaw(0, sizeof(p->u.aHash));
//if ( aiValues == null )
//{
// return SQLITE_NOMEM;
//}
//else
{
Buffer.BlockCopy( p.u.aHash, 0, aiValues, 0, aiValues.Length * ( sizeof( u32 ) ) );// memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
p.u.apSub = new Bitvec[BITVEC_NPTR];//memset(p->u.apSub, 0, sizeof(p->u.apSub));
p.iDivisor = (u32)( ( p.iSize + BITVEC_NPTR - 1 ) / BITVEC_NPTR );
rc = sqlite3BitvecSet( p, i );
for ( j = 0; j < BITVEC_NINT; j++ )
{
if ( aiValues[j] != 0 )
rc |= sqlite3BitvecSet( p, aiValues[j] );
}
//sqlite3StackFree( null, aiValues );
return rc;
}
}
bitvec_set_end:
p.nSet++;
p.u.aHash[h] = i;
return SQLITE_OK;
}
/*
** Clear the i-th bit.
**
** pBuf must be a pointer to at least BITVEC_SZ bytes of temporary storage
** that BitvecClear can use to rebuilt its hash table.
*/
static void sqlite3BitvecClear( Bitvec p, u32 i, u32[] pBuf )
{
if ( p == null )
return;
Debug.Assert( i > 0 );
i--;
while ( p.iDivisor != 0 )
{
u32 bin = i / p.iDivisor;
i = i % p.iDivisor;
p = p.u.apSub[bin];
if ( null == p )
{
return;
}
}
if ( p.iSize <= BITVEC_NBIT )
{
p.u.aBitmap[i / BITVEC_SZELEM] &= (byte)~( ( 1 << (int)( i & ( BITVEC_SZELEM - 1 ) ) ) );
}
else
{
u32 j;
u32[] aiValues = pBuf;
Array.Copy( p.u.aHash, aiValues, p.u.aHash.Length );//memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
p.u.aHash = new u32[aiValues.Length];// memset(p->u.aHash, 0, sizeof(p->u.aHash));
p.nSet = 0;
for ( j = 0; j < BITVEC_NINT; j++ )
{
if ( aiValues[j] != 0 && aiValues[j] != ( i + 1 ) )
{
u32 h = BITVEC_HASH( aiValues[j] - 1 );
p.nSet++;
while ( p.u.aHash[h] != 0 )
{
h++;
if ( h >= BITVEC_NINT )
h = 0;
}
p.u.aHash[h] = aiValues[j];
}
}
}
}
/*
** Destroy a bitmap object. Reclaim all memory used.
*/
static void sqlite3BitvecDestroy( ref Bitvec p )
{
if ( p == null )
return;
if ( p.iDivisor != 0 )
{
u32 i;
for ( i = 0; i < BITVEC_NPTR; i++ )
{
sqlite3BitvecDestroy( ref p.u.apSub[i] );
}
}
//sqlite3_free( ref p );
}
/*
** Return the value of the iSize parameter specified when Bitvec *p
** was created.
*/
static u32 sqlite3BitvecSize( Bitvec p )
{
return p.iSize;
}
#if !SQLITE_OMIT_BUILTIN_TEST
/*
** Let V[] be an array of unsigned characters sufficient to hold
** up to N bits. Let I be an integer between 0 and N. 0<=I<N.
** Then the following macros can be used to set, clear, or test
** individual bits within V.
*/
//#define SETBIT(V,I) V[I>>3] |= (1<<(I&7))
static void SETBIT( byte[] V, int I )
{
V[I >> 3] |= (byte)( 1 << ( I & 7 ) );
}
//#define CLEARBIT(V,I) V[I>>3] &= ~(1<<(I&7))
static void CLEARBIT( byte[] V, int I )
{
V[I >> 3] &= (byte)~( 1 << ( I & 7 ) );
}
//#define TESTBIT(V,I) (V[I>>3]&(1<<(I&7)))!=0
static int TESTBIT( byte[] V, int I )
{
return ( V[I >> 3] & ( 1 << ( I & 7 ) ) ) != 0 ? 1 : 0;
}
/*
** This routine runs an extensive test of the Bitvec code.
**
** The input is an array of integers that acts as a program
** to test the Bitvec. The integers are opcodes followed
** by 0, 1, or 3 operands, depending on the opcode. Another
** opcode follows immediately after the last operand.
**
** There are 6 opcodes numbered from 0 through 5. 0 is the
** "halt" opcode and causes the test to end.
**
** 0 Halt and return the number of errors
** 1 N S X Set N bits beginning with S and incrementing by X
** 2 N S X Clear N bits beginning with S and incrementing by X
** 3 N Set N randomly chosen bits
** 4 N Clear N randomly chosen bits
** 5 N S X Set N bits from S increment X in array only, not in bitvec
**
** The opcodes 1 through 4 perform set and clear operations are performed
** on both a Bitvec object and on a linear array of bits obtained from malloc.
** Opcode 5 works on the linear array only, not on the Bitvec.
** Opcode 5 is used to deliberately induce a fault in order to
** confirm that error detection works.
**
** At the conclusion of the test the linear array is compared
** against the Bitvec object. If there are any differences,
** an error is returned. If they are the same, zero is returned.
**
** If a memory allocation error occurs, return -1.
*/
static int sqlite3BitvecBuiltinTest( u32 sz, int[] aOp )
{
Bitvec pBitvec = null;
byte[] pV = null;
int rc = -1;
int i, nx, pc, op;
u32[] pTmpSpace;
/* Allocate the Bitvec to be tested and a linear array of
** bits to act as the reference */
pBitvec = sqlite3BitvecCreate( sz );
pV = sqlite3_malloc( (int)( sz + 7 ) / 8 + 1 );
pTmpSpace = new u32[BITVEC_SZ];// sqlite3_malloc( BITVEC_SZ );
if ( pBitvec == null || pV == null || pTmpSpace == null )
goto bitvec_end;
Array.Clear( pV, 0, (int)( sz + 7 ) / 8 + 1 );// memset( pV, 0, ( sz + 7 ) / 8 + 1 );
/* NULL pBitvec tests */
sqlite3BitvecSet( null, (u32)1 );
sqlite3BitvecClear( null, 1, pTmpSpace );
/* Run the program */
pc = 0;
while ( ( op = aOp[pc] ) != 0 )
{
switch ( op )
{
case 1:
case 2:
case 5:
{
nx = 4;
i = aOp[pc + 2] - 1;
aOp[pc + 2] += aOp[pc + 3];
break;
}
case 3:
case 4:
default:
{
nx = 2;
i64 i64Temp = 0;
sqlite3_randomness( sizeof( i64 ), ref i64Temp );
i = (int)i64Temp;
break;
}
}
if ( ( --aOp[pc + 1] ) > 0 )
nx = 0;
pc += nx;
i = (int)( ( i & 0x7fffffff ) % sz );
if ( ( op & 1 ) != 0 )
{
SETBIT( pV, ( i + 1 ) );
if ( op != 5 )
{
if ( sqlite3BitvecSet( pBitvec, (u32)i + 1 ) != 0 )
goto bitvec_end;
}
}
else
{
CLEARBIT( pV, ( i + 1 ) );
sqlite3BitvecClear( pBitvec, (u32)i + 1, pTmpSpace );
}
}
/* Test to make sure the linear array exactly matches the
** Bitvec object. Start with the assumption that they do
** match (rc==0). Change rc to non-zero if a discrepancy
** is found.
*/
rc = sqlite3BitvecTest( null, 0 ) + sqlite3BitvecTest( pBitvec, sz + 1 )
+ sqlite3BitvecTest( pBitvec, 0 )
+ (int)( sqlite3BitvecSize( pBitvec ) - sz );
for ( i = 1; i <= sz; i++ )
{
if ( ( TESTBIT( pV, i ) ) != sqlite3BitvecTest( pBitvec, (u32)i ) )
{
rc = i;
break;
}
}
/* Free allocated structure */
bitvec_end:
//sqlite3_free( ref pTmpSpace );
//sqlite3_free( ref pV );
sqlite3BitvecDestroy( ref pBitvec );
return rc;
}
#endif //* SQLITE_OMIT_BUILTIN_TEST */
}
}