SQLite

** expressions are the same.  But if you get a 0 or 1 return, then you
** can be sure the expressions are the same.  In the places where
** this routine is used, it does not hurt to get an extra 2 - that
** just might result in some slightly slower code.  But returning
** an incorrect 0 or 1 could lead to a malfunction.
*/
int sqlite3ExprCompare(Expr *pA, Expr *pB){

  if( pA==0||pB==0 ){
    return pB==pA ? 0 : 2;
  }
  assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
  assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
  if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
    return 2;
  }
  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
  if( pA->op!=pB->op ) return 2;
  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;
  if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList) ) return 2;











  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
  if( ExprHasProperty(pA, EP_IntValue) ){
    if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
      return 2;
    }
  }else if( pA->op!=TK_COLUMN && pA->u.zToken ){
    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
    if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ){
      return 2;
    }
  }
  if( (pA->flags & EP_ExpCollate)!=(pB->flags & EP_ExpCollate) ) return 1;
  if( (pA->flags & EP_ExpCollate)!=0 && pA->pColl!=pB->pColl ) return 2;
  return 0;
}

/*
** Compare two ExprList objects.  Return 0 if they are identical and 
** non-zero if they differ in any way.
**
** This routine might return non-zero for equivalent ExprLists.  The
** only consequence will be disabled optimizations.  But this routine
** must never return 0 if the two ExprList objects are different, or
** a malfunction will result.
**
** Two NULL pointers are considered to be the same.  But a NULL pointer
** always differs from a non-NULL pointer.
*/
int sqlite3ExprListCompare(ExprList *pA, ExprList *pB){
  int i;
  if( pA==0 && pB==0 ) return 0;
  if( pA==0 || pB==0 ) return 1;
  if( pA->nExpr!=pB->nExpr ) return 1;
  for(i=0; i<pA->nExpr; i++){
    Expr *pExprA = pA->a[i].pExpr;
    Expr *pExprB = pB->a[i].pExpr;
    if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
    if( sqlite3ExprCompare(pExprA, pExprB) ) return 1;
  }
  return 0;
}

/*
** Add a new element to the pAggInfo->aCol[] array.  Return the index of
** the new element.  Return a negative number if malloc fails.
*/
static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
  int i;

      sqlite3_result_text(context, sqlite3StrAccumFinish(pAccum), -1, 
                          sqlite3_free);
    }
  }
}

/*
** This routine does per-connection function registration.  Most
** of the built-in functions above are part of the global function set.
** This routine only deals with those that are not global.
*/
void sqlite3RegisterBuiltinFunctions(sqlite3 *db){

  int rc = sqlite3_overload_function(db, "MATCH", 2);
  assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
  if( rc==SQLITE_NOMEM ){
    db->mallocFailed = 1;

  }
}

/*
** Set the LIKEOPT flag on the 2-argument function with the given name.
*/
static void setLikeOptFlag(sqlite3 *db, const char *zName, u8 flagVal){

  **
  ** The first form reports the current persistent setting for the
  ** page cache size.  The value returned is the maximum number of
  ** pages in the page cache.  The second form sets both the current
  ** page cache size value and the persistent page cache size value
  ** stored in the database file.
  **
  ** Older versions of SQLite would set the default cache size to a
  ** negative number to indicate synchronous=OFF.  These days, synchronous
  ** is always on by default regardless of the sign of the default cache
  ** size.  But continue to take the absolute value of the default cache
  ** size of historical compatibility.
  */
  if( sqlite3StrICmp(zLeft,"default_cache_size")==0 ){
    static const VdbeOpList getCacheSize[] = {
      { OP_Transaction, 0, 0,        0},                         /* 0 */
      { OP_ReadCookie,  0, 1,        BTREE_DEFAULT_CACHE_SIZE},  /* 1 */
      { OP_IfPos,       1, 7,        0},
      { OP_Integer,     0, 2,        0},

      sqlite3VdbeChangeP1(v, addr+1, iDb);
      sqlite3VdbeChangeP1(v, addr+6, SQLITE_DEFAULT_CACHE_SIZE);
    }else{
      int size = atoi(zRight);
      if( size<0 ) size = -size;
      sqlite3BeginWriteOperation(pParse, 0, iDb);
      sqlite3VdbeAddOp2(v, OP_Integer, size, 1);




      sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_DEFAULT_CACHE_SIZE, 1);
      pDb->pSchema->cache_size = size;
      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
    }
  }else

  /*

  assert( p->pGroupBy==0 || (p->selFlags & SF_Aggregate)!=0 );
  if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct ){
    p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
    pGroupBy = p->pGroupBy;
    p->selFlags &= ~SF_Distinct;
    isDistinct = 0;
  }

  /* If there is both a GROUP BY and an ORDER BY clause and they are
  ** identical, then disable the ORDER BY clause since the GROUP BY
  ** will cause elements to come out in the correct order.  This is
  ** an optimization - the correct answer should result regardless.
  ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
  ** to disable this optimization for testing purposes.
  */
  if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy)==0
         && (db->flags & SQLITE_GroupByOrder)==0 ){
    pOrderBy = 0;
  }

  /* If there is an ORDER BY clause, then this sorting
  ** index might end up being unused if the data can be 
  ** extracted in pre-sorted order.  If that is the case, then the
  ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
  ** we figure out that the sorting index is not needed.  The addrSortIndex
  ** variable is used to facilitate that change.

** These must be the low-order bits of the flags field.
*/
#define SQLITE_QueryFlattener 0x01        /* Disable query flattening */
#define SQLITE_ColumnCache    0x02        /* Disable the column cache */
#define SQLITE_IndexSort      0x04        /* Disable indexes for sorting */
#define SQLITE_IndexSearch    0x08        /* Disable indexes for searching */
#define SQLITE_IndexCover     0x10        /* Disable index covering table */
#define SQLITE_GroupByOrder   0x20        /* Disable GROUPBY cover of ORDERBY */
#define SQLITE_OptMask        0xff        /* Mask of all disablable opts */

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */

Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
void sqlite3Vacuum(Parse*);
int sqlite3RunVacuum(char**, sqlite3*);
char *sqlite3NameFromToken(sqlite3*, Token*);
int sqlite3ExprCompare(Expr*, Expr*);
int sqlite3ExprListCompare(ExprList*, ExprList*);
void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
Vdbe *sqlite3GetVdbe(Parse*);
void sqlite3PrngSaveState(void);
void sqlite3PrngRestoreState(void);
void sqlite3PrngResetState(void);
void sqlite3RollbackAll(sqlite3*);

/*
** A utility for printing all or part of an SQLite database file.
*/
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>


static int pagesize = 1024;     /* Size of a database page */
static int db = -1;             /* File descriptor for reading the DB */
static int mxPage = 0;          /* Last page number */
static int perLine = 16;        /* HEX elements to print per line */

typedef long long int i64;      /* Datatype for 64-bit integers */


/*
** Convert the var-int format into i64.  Return the number of bytes
** in the var-int.  Write the var-int value into *pVal.
*/
static int decodeVarint(const unsigned char *z, i64 *pVal){
  i64 v = 0;
  int i;
  for(i=0; i<8; i++){
    v = (v<<7) + (z[i]&0x7f);
    if( (z[i]&0x80)==0 ){ *pVal = v; return i+1; }
  }
  v = (v<<8) + (z[i]&0xff);
  *pVal = v;
  return 9;
}

/* Report an out-of-memory error and die.
*/
static void out_of_memory(void){
  fprintf(stderr,"Out of memory...\n");
  exit(1);
}

/*
** Read content from the file.
**
** Space to hold the content is obtained from malloc() and needs to be
** freed by the caller.
*/
static unsigned char *getContent(int ofst, int nByte){
  unsigned char *aData;

  aData = malloc(nByte);
  if( aData==0 ) out_of_memory();
  lseek(db, ofst, SEEK_SET);
  read(db, aData, nByte);
  return aData;
}

/*
** Print a range of bytes as hex and as ascii.
*/
static unsigned char *print_byte_range(
  int ofst,          /* First byte in the range of bytes to print */
  int nByte,         /* Number of bytes to print */
  int printOfst      /* Add this amount to the index on the left column */
){
  unsigned char *aData;
  int i, j;
  const char *zOfstFmt;

  if( ((printOfst+nByte)&~0xfff)==0 ){
    zOfstFmt = " %03x: ";
  }else if( ((printOfst+nByte)&~0xffff)==0 ){
    zOfstFmt = " %04x: ";
  }else if( ((printOfst+nByte)&~0xfffff)==0 ){
    zOfstFmt = " %05x: ";
  }else if( ((printOfst+nByte)&~0xffffff)==0 ){
    zOfstFmt = " %06x: ";
  }else{
    zOfstFmt = " %08x: ";
  }

  aData = getContent(ofst, nByte);
  for(i=0; i<nByte; i += perLine){
    fprintf(stdout, zOfstFmt, i+printOfst);
    for(j=0; j<perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, "   ");
      }else{
        fprintf(stdout,"%02x ", aData[i+j]);
      }
    }
    for(j=0; j<perLine; j++){
      if( i+j>nByte ){
        fprintf(stdout, " ");
      }else{
        fprintf(stdout,"%c", isprint(aData[i+j]) ? aData[i+j] : '.');
      }
    }
    fprintf(stdout,"\n");
  }
  return aData;
}

/*
** Print an entire page of content as hex
*/
static print_page(int iPg){
  int iStart;
  unsigned char *aData;
  iStart = (iPg-1)*pagesize;
  fprintf(stdout, "Page %d:   (offsets 0x%x..0x%x)\n",
          iPg, iStart, iStart+pagesize-1);
  aData = print_byte_range(iStart, pagesize, 0);
  free(aData);
}

/* Print a line of decode output showing a 4-byte integer.
*/
static print_decode_line(
  unsigned char *aData,      /* Content being decoded */
  int ofst, int nByte,       /* Start and size of decode */
  const char *zMsg           /* Message to append */
){
  int i, j;
  int val = aData[ofst];
  char zBuf[100];
  sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
  i = strlen(zBuf);
  for(j=1; j<4; j++){
    if( j>=nByte ){
      sprintf(&zBuf[i], "   ");
    }else{
      sprintf(&zBuf[i], " %02x", aData[ofst+j]);
      val = val*256 + aData[ofst+j];
    }
    i += strlen(&zBuf[i]);
  }
  sprintf(&zBuf[i], "   %9d", val);
  printf("%s  %s\n", zBuf, zMsg);
}

/*
** Decode the database header.
*/
static void print_db_header(void){
  unsigned char *aData;
  aData = print_byte_range(0, 100, 0);
  printf("Decoded:\n");
  print_decode_line(aData, 16, 2, "Database page size");
  print_decode_line(aData, 18, 1, "File format write version");
  print_decode_line(aData, 19, 1, "File format read version");
  print_decode_line(aData, 20, 1, "Reserved space at end of page");
  print_decode_line(aData, 24, 4, "File change counter");
  print_decode_line(aData, 28, 4, "Size of database in pages");
  print_decode_line(aData, 32, 4, "Page number of first freelist page");
  print_decode_line(aData, 36, 4, "Number of freelist pages");
  print_decode_line(aData, 40, 4, "Schema cookie");
  print_decode_line(aData, 44, 4, "Schema format version");
  print_decode_line(aData, 48, 4, "Default page cache size");
  print_decode_line(aData, 52, 4, "Largest auto-vac root page");
  print_decode_line(aData, 56, 4, "Text encoding");
  print_decode_line(aData, 60, 4, "User version");
  print_decode_line(aData, 64, 4, "Incremental-vacuum mode");
  print_decode_line(aData, 68, 4, "meta[7]");
  print_decode_line(aData, 72, 4, "meta[8]");
  print_decode_line(aData, 76, 4, "meta[9]");
  print_decode_line(aData, 80, 4, "meta[10]");
  print_decode_line(aData, 84, 4, "meta[11]");
  print_decode_line(aData, 88, 4, "meta[12]");
  print_decode_line(aData, 92, 4, "meta[13]");
  print_decode_line(aData, 96, 4, "SQLite version number");
}

/*
** Create a description for a single cell.
*/
static int describeCell(unsigned char cType, unsigned char *a, char **pzDesc){
  int i;
  int nDesc = 0;
  int n = 0;
  int leftChild;
  i64 nPayload;
  i64 rowid;
  static char zDesc[100];
  i = 0;
  if( cType<=5 ){
    leftChild = ((a[0]*256 + a[1])*256 + a[2])*256 + a[3];
    a += 4;
    n += 4;
    sprintf(zDesc, "left-child: %d ", leftChild);
    nDesc = strlen(zDesc);
  }
  if( cType!=5 ){
    i = decodeVarint(a, &nPayload);
    a += i;
    n += i;
    sprintf(&zDesc[nDesc], "sz: %lld ", nPayload);
    nDesc += strlen(&zDesc[nDesc]);
  }
  if( cType==5 || cType==13 ){
    i = decodeVarint(a, &rowid);
    a += i;
    n += i;
    sprintf(&zDesc[nDesc], "rowid: %lld ", rowid);
    nDesc += strlen(&zDesc[nDesc]);
  }
  *pzDesc = zDesc;
  return n;
}

/*
** Decode a btree page
*/
static void decode_btree_page(unsigned char *a, int pgno, int hdrSize){
  const char *zType = "unknown";
  int nCell;
  int i;
  int iCellPtr;
  switch( a[0] ){
    case 2:  zType = "index interior node";  break;
    case 5:  zType = "table interior node";  break;
    case 10: zType = "index leaf";           break;
    case 13: zType = "table leaf";           break;
  }
  printf("Decode of btree page %d:\n", pgno);
  print_decode_line(a, 0, 1, zType);
  print_decode_line(a, 1, 2, "Offset to first freeblock");
  print_decode_line(a, 3, 2, "Number of cells on this page");
  nCell = a[3]*256 + a[4];
  print_decode_line(a, 5, 2, "Offset to cell content area");
  print_decode_line(a, 7, 1, "Fragmented byte count");
  if( a[0]==2 || a[0]==5 ){
    print_decode_line(a, 8, 4, "Right child");
    iCellPtr = 12;
  }else{
    iCellPtr = 8;
  }
  for(i=0; i<nCell; i++){
    int cofst = iCellPtr + i*2;
    char *zDesc;
    cofst = a[cofst]*256 + a[cofst+1];
    describeCell(a[0], &a[cofst-hdrSize], &zDesc);
    printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
  }
}

int main(int argc, char **argv){
  struct stat sbuf;
  unsigned char zPgSz[2];
  if( argc<2 ){
    fprintf(stderr,"Usage: %s FILENAME ?PAGE? ...\n", argv[0]);
    exit(1);
  }
  db = open(argv[1], O_RDONLY);
  if( db<0 ){
    fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
    exit(1);
  }
  zPgSz[0] = 0;
  zPgSz[1] = 0;
  lseek(db, 16, SEEK_SET);
  read(db, zPgSz, 2);
  pagesize = zPgSz[0]*256 + zPgSz[1];
  if( pagesize==0 ) pagesize = 1024;
  printf("Pagesize: %d\n", pagesize);
  fstat(db, &sbuf);
  mxPage = sbuf.st_size/pagesize;
  printf("Available pages: 1..%d\n", mxPage);
  if( argc==2 ){
    int i;
    for(i=1; i<=mxPage; i++) print_page(i);
  }else{
    int i;
    for(i=2; i<argc; i++){
      int iStart, iEnd;
      char *zLeft;
      if( strcmp(argv[i], "dbheader")==0 ){
        print_db_header();
        continue;
      }
      if( !isdigit(argv[i][0]) ){
        fprintf(stderr, "%s: unknown option: [%s]\n", argv[0], argv[i]);
        continue;
      }
      iStart = strtol(argv[i], &zLeft, 0);
      if( zLeft && strcmp(zLeft,"..end")==0 ){
        iEnd = mxPage;
      }else if( zLeft && zLeft[0]=='.' && zLeft[1]=='.' ){
        iEnd = strtol(&zLeft[2], 0, 0);
      }else if( zLeft && zLeft[0]=='b' ){
        int ofst, nByte, hdrSize;
        unsigned char *a;
        if( iStart==1 ){
          ofst = hdrSize = 100;
          nByte = pagesize-100;
        }else{
          hdrSize = 0;
          ofst = (iStart-1)*pagesize;
          nByte = pagesize;
        }
        a = getContent(ofst, nByte);
        decode_btree_page(a, iStart, hdrSize);
        free(a);
        continue;
      }else{
        iEnd = iStart;
      }
      if( iStart<1 || iEnd<iStart || iEnd>mxPage ){
        fprintf(stderr,
          "Page argument should be LOWER?..UPPER?.  Range 1 to %d\n",
          mxPage);