| Index: third_party/sqlite/src/bitvec.c
|
| ===================================================================
|
| --- third_party/sqlite/src/bitvec.c (revision 56608)
|
| +++ third_party/sqlite/src/bitvec.c (working copy)
|
| @@ -1,410 +0,0 @@
|
| -/*
|
| -** 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.
|
| -**
|
| -** @(#) $Id: bitvec.c,v 1.17 2009/07/25 17:33:26 drh Exp $
|
| -*/
|
| -#include "sqliteInt.h"
|
| -
|
| -/* Size of the Bitvec structure in bytes. */
|
| -#define BITVEC_SZ (sizeof(void*)*128) /* 512 on 32bit. 1024 on 64bit */
|
| -
|
| -/* 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*))
|
| -
|
| -/* 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
|
| -/* Size, in bits, of the bitmap element. */
|
| -#define BITVEC_SZELEM 8
|
| -/* Number of elements in a bitmap array. */
|
| -#define BITVEC_NELEM (BITVEC_USIZE/sizeof(BITVEC_TELEM))
|
| -/* Number of bits in the bitmap array. */
|
| -#define BITVEC_NBIT (BITVEC_NELEM*BITVEC_SZELEM)
|
| -
|
| -/* Number of u32 values in hash table. */
|
| -#define BITVEC_NINT (BITVEC_USIZE/sizeof(u32))
|
| -/* Maximum number of entries in hash table before
|
| -** sub-dividing and re-hashing. */
|
| -#define BITVEC_MXHASH (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)
|
| -
|
| -#define BITVEC_NPTR (BITVEC_USIZE/sizeof(Bitvec *))
|
| -
|
| -
|
| -/*
|
| -** A bitmap is an instance of the following structure.
|
| -**
|
| -** This bitmap records the existance 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.
|
| -*/
|
| -struct Bitvec {
|
| - u32 iSize; /* Maximum bit index. Max iSize is 4,294,967,296. */
|
| - 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. */
|
| - 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. */
|
| - union {
|
| - BITVEC_TELEM aBitmap[BITVEC_NELEM]; /* Bitmap representation */
|
| - u32 aHash[BITVEC_NINT]; /* Hash table representation */
|
| - Bitvec *apSub[BITVEC_NPTR]; /* Recursive representation */
|
| - } u;
|
| -};
|
| -
|
| -/*
|
| -** 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.
|
| -*/
|
| -Bitvec *sqlite3BitvecCreate(u32 iSize){
|
| - Bitvec *p;
|
| - assert( sizeof(*p)==BITVEC_SZ );
|
| - p = sqlite3MallocZero( sizeof(*p) );
|
| - if( p ){
|
| - 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.
|
| -*/
|
| -int sqlite3BitvecTest(Bitvec *p, u32 i){
|
| - if( p==0 ) return 0;
|
| - if( i>p->iSize || i==0 ) return 0;
|
| - i--;
|
| - while( p->iDivisor ){
|
| - u32 bin = i/p->iDivisor;
|
| - i = i%p->iDivisor;
|
| - p = p->u.apSub[bin];
|
| - if (!p) {
|
| - return 0;
|
| - }
|
| - }
|
| - if( p->iSize<=BITVEC_NBIT ){
|
| - return (p->u.aBitmap[i/BITVEC_SZELEM] & (1<<(i&(BITVEC_SZELEM-1))))!=0;
|
| - } else{
|
| - u32 h = BITVEC_HASH(i++);
|
| - while( p->u.aHash[h] ){
|
| - 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.
|
| -*/
|
| -int sqlite3BitvecSet(Bitvec *p, u32 i){
|
| - u32 h;
|
| - if( p==0 ) return SQLITE_OK;
|
| - assert( i>0 );
|
| - assert( i<=p->iSize );
|
| - i--;
|
| - while((p->iSize > BITVEC_NBIT) && p->iDivisor) {
|
| - u32 bin = i/p->iDivisor;
|
| - i = i%p->iDivisor;
|
| - if( p->u.apSub[bin]==0 ){
|
| - p->u.apSub[bin] = sqlite3BitvecCreate( p->iDivisor );
|
| - if( p->u.apSub[bin]==0 ) return SQLITE_NOMEM;
|
| - }
|
| - p = p->u.apSub[bin];
|
| - }
|
| - if( p->iSize<=BITVEC_NBIT ){
|
| - p->u.aBitmap[i/BITVEC_SZELEM] |= 1 << (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( !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] );
|
| - /* 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 ){
|
| - unsigned int j;
|
| - int rc;
|
| - u32 *aiValues = sqlite3StackAllocRaw(0, sizeof(p->u.aHash));
|
| - if( aiValues==0 ){
|
| - return SQLITE_NOMEM;
|
| - }else{
|
| - memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
|
| - memset(p->u.apSub, 0, sizeof(p->u.apSub));
|
| - p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
|
| - rc = sqlite3BitvecSet(p, i);
|
| - for(j=0; j<BITVEC_NINT; j++){
|
| - if( aiValues[j] ) rc |= sqlite3BitvecSet(p, aiValues[j]);
|
| - }
|
| - sqlite3StackFree(0, 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.
|
| -*/
|
| -void sqlite3BitvecClear(Bitvec *p, u32 i, void *pBuf){
|
| - if( p==0 ) return;
|
| - assert( i>0 );
|
| - i--;
|
| - while( p->iDivisor ){
|
| - u32 bin = i/p->iDivisor;
|
| - i = i%p->iDivisor;
|
| - p = p->u.apSub[bin];
|
| - if (!p) {
|
| - return;
|
| - }
|
| - }
|
| - if( p->iSize<=BITVEC_NBIT ){
|
| - p->u.aBitmap[i/BITVEC_SZELEM] &= ~(1 << (i&(BITVEC_SZELEM-1)));
|
| - }else{
|
| - unsigned int j;
|
| - u32 *aiValues = pBuf;
|
| - memcpy(aiValues, p->u.aHash, sizeof(p->u.aHash));
|
| - memset(p->u.aHash, 0, sizeof(p->u.aHash));
|
| - p->nSet = 0;
|
| - for(j=0; j<BITVEC_NINT; j++){
|
| - if( aiValues[j] && aiValues[j]!=(i+1) ){
|
| - u32 h = BITVEC_HASH(aiValues[j]-1);
|
| - p->nSet++;
|
| - while( p->u.aHash[h] ){
|
| - h++;
|
| - if( h>=BITVEC_NINT ) h = 0;
|
| - }
|
| - p->u.aHash[h] = aiValues[j];
|
| - }
|
| - }
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Destroy a bitmap object. Reclaim all memory used.
|
| -*/
|
| -void sqlite3BitvecDestroy(Bitvec *p){
|
| - if( p==0 ) return;
|
| - if( p->iDivisor ){
|
| - unsigned int i;
|
| - for(i=0; i<BITVEC_NPTR; i++){
|
| - sqlite3BitvecDestroy(p->u.apSub[i]);
|
| - }
|
| - }
|
| - sqlite3_free(p);
|
| -}
|
| -
|
| -/*
|
| -** Return the value of the iSize parameter specified when Bitvec *p
|
| -** was created.
|
| -*/
|
| -u32 sqlite3BitvecSize(Bitvec *p){
|
| - return p->iSize;
|
| -}
|
| -
|
| -#ifndef 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))
|
| -#define CLEARBIT(V,I) V[I>>3] &= ~(1<<(I&7))
|
| -#define TESTBIT(V,I) (V[I>>3]&(1<<(I&7)))!=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.
|
| -*/
|
| -int sqlite3BitvecBuiltinTest(int sz, int *aOp){
|
| - Bitvec *pBitvec = 0;
|
| - unsigned char *pV = 0;
|
| - int rc = -1;
|
| - int i, nx, pc, op;
|
| - void *pTmpSpace;
|
| -
|
| - /* Allocate the Bitvec to be tested and a linear array of
|
| - ** bits to act as the reference */
|
| - pBitvec = sqlite3BitvecCreate( sz );
|
| - pV = sqlite3_malloc( (sz+7)/8 + 1 );
|
| - pTmpSpace = sqlite3_malloc(BITVEC_SZ);
|
| - if( pBitvec==0 || pV==0 || pTmpSpace==0 ) goto bitvec_end;
|
| - memset(pV, 0, (sz+7)/8 + 1);
|
| -
|
| - /* NULL pBitvec tests */
|
| - sqlite3BitvecSet(0, 1);
|
| - sqlite3BitvecClear(0, 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;
|
| - sqlite3_randomness(sizeof(i), &i);
|
| - break;
|
| - }
|
| - }
|
| - if( (--aOp[pc+1]) > 0 ) nx = 0;
|
| - pc += nx;
|
| - i = (i & 0x7fffffff)%sz;
|
| - if( (op & 1)!=0 ){
|
| - SETBIT(pV, (i+1));
|
| - if( op!=5 ){
|
| - if( sqlite3BitvecSet(pBitvec, i+1) ) goto bitvec_end;
|
| - }
|
| - }else{
|
| - CLEARBIT(pV, (i+1));
|
| - sqlite3BitvecClear(pBitvec, 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(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
|
| - + sqlite3BitvecTest(pBitvec, 0)
|
| - + (sqlite3BitvecSize(pBitvec) - sz);
|
| - for(i=1; i<=sz; i++){
|
| - if( (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
|
| - rc = i;
|
| - break;
|
| - }
|
| - }
|
| -
|
| - /* Free allocated structure */
|
| -bitvec_end:
|
| - sqlite3_free(pTmpSpace);
|
| - sqlite3_free(pV);
|
| - sqlite3BitvecDestroy(pBitvec);
|
| - return rc;
|
| -}
|
| -#endif /* SQLITE_OMIT_BUILTIN_TEST */
|
|
|