SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE


/* series_cursor is a subclas of sqlite3_vtab_cursor which will
** serve as the underlying representation of a cursor that scans
** over rows of the result
*/
typedef struct series_cursor series_cursor;
struct series_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  int isDesc;                /* True to count down rather than up */
................................................................................
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3_vtab *pNew;
  pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) );
  if( pNew==0 ) return SQLITE_NOMEM;

/* Column numbers */
#define SERIES_COLUMN_VALUE 0
#define SERIES_COLUMN_START 1
#define SERIES_COLUMN_STOP  2
#define SERIES_COLUMN_STEP  3

  sqlite3_declare_vtab(db,
     "CREATE TABLE x(value,start hidden,stop hidden,step hidden)");



  memset(pNew, 0, sizeof(*pNew));

  return SQLITE_OK;
}

/*
** This method is the destructor for series_cursor objects.
*/
static int seriesDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
................................................................................
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
#ifndef SQLITE_OMIT_VIRTUALTABLE





  rc = sqlite3_create_module(db, "generate_series", &seriesModule, 0);
#endif
  return rc;
}

SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE


/* series_cursor is a subclass of sqlite3_vtab_cursor which will
** serve as the underlying representation of a cursor that scans
** over rows of the result
*/
typedef struct series_cursor series_cursor;
struct series_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  int isDesc;                /* True to count down rather than up */
................................................................................
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3_vtab *pNew;
  int rc;


/* Column numbers */
#define SERIES_COLUMN_VALUE 0
#define SERIES_COLUMN_START 1
#define SERIES_COLUMN_STOP  2
#define SERIES_COLUMN_STEP  3

  rc = sqlite3_declare_vtab(db,
     "CREATE TABLE x(value,start hidden,stop hidden,step hidden)");
  if( rc==SQLITE_OK ){
    pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) );
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
  }
  return rc;
}

/*
** This method is the destructor for series_cursor objects.
*/
static int seriesDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
................................................................................
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( sqlite3_libversion_number()<3008012 ){
    *pzErrMsg = sqlite3_mprintf(
        "generate_series() requires SQLite 3.8.12 or later");
    return SQLITE_ERROR;
  }
  rc = sqlite3_create_module(db, "generate_series", &seriesModule, 0);
#endif
  return rc;
}

  ** and code in pParse and return NULL. */
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    return 0;
  }

  p = sqlite3FindTable(pParse->db, zName, zDbase);
  if( p==0 ){

#ifndef SQLITE_OMIT_VIRTUAL_TABLE
    /* If zName is the not the name of a table in the schema created using
    ** CREATE, then check to see if it is the name of an virtual table that
    ** can be an eponymous virtual table. */
    Module *pMod = (Module*)sqlite3HashFind(&pParse->db->aModule, zName);
    if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
      return pMod->pEpoTab;
    }
#endif
    const char *zMsg = isView ? "no such view" : "no such table";
    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }
................................................................................
}

/*
** Add the list of function arguments to the SrcList entry for a
** table-valued-function.
*/
void sqlite3SrcListFuncArgs(Parse *pParse, SrcList *p, ExprList *pList){
  if( p && ALWAYS(p->nSrc>0) ){
    struct SrcList_item *pItem = &p->a[p->nSrc-1];
    assert( pItem->fg.notIndexed==0 );
    assert( pItem->fg.isIndexedBy==0 );
    assert( pItem->fg.isTabFunc==0 );
    pItem->u1.pFuncArg = pList;
    pItem->fg.isTabFunc = 1;


  }
}

/*
** When building up a FROM clause in the parser, the join operator
** is initially attached to the left operand.  But the code generator
** expects the join operator to be on the right operand.  This routine

  ** and code in pParse and return NULL. */
  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
    return 0;
  }

  p = sqlite3FindTable(pParse->db, zName, zDbase);
  if( p==0 ){
    const char *zMsg = isView ? "no such view" : "no such table";
#ifndef SQLITE_OMIT_VIRTUAL_TABLE
    /* If zName is the not the name of a table in the schema created using
    ** CREATE, then check to see if it is the name of an virtual table that
    ** can be an eponymous virtual table. */
    Module *pMod = (Module*)sqlite3HashFind(&pParse->db->aModule, zName);
    if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
      return pMod->pEpoTab;
    }
#endif

    if( zDbase ){
      sqlite3ErrorMsg(pParse, "%s: %s.%s", zMsg, zDbase, zName);
    }else{
      sqlite3ErrorMsg(pParse, "%s: %s", zMsg, zName);
    }
    pParse->checkSchema = 1;
  }
................................................................................
}

/*
** Add the list of function arguments to the SrcList entry for a
** table-valued-function.
*/
void sqlite3SrcListFuncArgs(Parse *pParse, SrcList *p, ExprList *pList){
  if( p && pList ){
    struct SrcList_item *pItem = &p->a[p->nSrc-1];
    assert( pItem->fg.notIndexed==0 );
    assert( pItem->fg.isIndexedBy==0 );
    assert( pItem->fg.isTabFunc==0 );
    pItem->u1.pFuncArg = pList;
    pItem->fg.isTabFunc = 1;
  }else{
    sqlite3ExprListDelete(pParse->db, pList);
  }
}

/*
** When building up a FROM clause in the parser, the join operator
** is initially attached to the left operand.  But the code generator
** expects the join operator to be on the right operand.  This routine

** list rather than a single expression.
*/
int sqlite3ResolveExprListNames( 
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  ExprList *pList         /* The expression list to be analyzed. */
){
  int i;

  for(i=0; i<pList->nExpr; i++){
    if( sqlite3ResolveExprNames(pNC, pList->a[i].pExpr) ) return WRC_Abort;
  }
  return WRC_Continue;
}

/*

** list rather than a single expression.
*/
int sqlite3ResolveExprListNames( 
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  ExprList *pList         /* The expression list to be analyzed. */
){
  int i;
  assert( pList!=0 );
  for(i=0; i<pList->nExpr; i++){
    if( sqlite3ResolveExprNames(pNC, pList->a[i].pExpr) ) return WRC_Abort;
  }
  return WRC_Continue;
}

/*

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  sqlite3VdbeEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  assert( p->bIsReader || p->readOnly!=0 );
  p->rc = SQLITE_OK;
  p->iCurrentTime = 0;
  assert( p->explain==0 );
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
................................................................................
    rc = SQLITE_READONLY;
    goto abort_due_to_error;
  }
  pBt = db->aDb[pOp->p1].pBt;

  if( pBt ){
    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);


    if( rc==SQLITE_BUSY ){
      p->pc = (int)(pOp - aOp);
      p->rc = rc = SQLITE_BUSY;
      goto vdbe_return;
    }
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }

    if( pOp->p2 && p->usesStmtJournal 

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  sqlite3VdbeEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || (p->rc&0xff)==SQLITE_BUSY );
  assert( p->bIsReader || p->readOnly!=0 );
  p->rc = SQLITE_OK;
  p->iCurrentTime = 0;
  assert( p->explain==0 );
  p->pResultSet = 0;
  db->busyHandler.nBusy = 0;
  if( db->u1.isInterrupted ) goto abort_due_to_interrupt;
................................................................................
    rc = SQLITE_READONLY;
    goto abort_due_to_error;
  }
  pBt = db->aDb[pOp->p1].pBt;

  if( pBt ){
    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
    testcase( rc==SQLITE_BUSY_SNAPSHOT );
    testcase( rc==SQLITE_BUSY_RECOVERY );
    if( (rc&0xff)==SQLITE_BUSY ){
      p->pc = (int)(pOp - aOp);
      p->rc = rc;
      goto vdbe_return;
    }
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }

    if( pOp->p2 && p->usesStmtJournal 

  ** returned if this statement was compiled using the legacy 
  ** sqlite3_prepare() interface. According to the docs, this can only
  ** be one of the values in the first assert() below. Variable p->rc 
  ** contains the value that would be returned if sqlite3_finalize() 
  ** were called on statement p.
  */
  assert( rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR 
       || rc==SQLITE_BUSY || rc==SQLITE_MISUSE
  );
  assert( (p->rc!=SQLITE_ROW && p->rc!=SQLITE_DONE) || p->rc==p->rcApp );
  if( p->isPrepareV2 && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
    /* If this statement was prepared using sqlite3_prepare_v2(), and an
    ** error has occurred, then return the error code in p->rc to the
    ** caller. Set the error code in the database handle to the same value.
    */ 

  ** returned if this statement was compiled using the legacy 
  ** sqlite3_prepare() interface. According to the docs, this can only
  ** be one of the values in the first assert() below. Variable p->rc 
  ** contains the value that would be returned if sqlite3_finalize() 
  ** were called on statement p.
  */
  assert( rc==SQLITE_ROW  || rc==SQLITE_DONE   || rc==SQLITE_ERROR 
       || (rc&0xff)==SQLITE_BUSY || rc==SQLITE_MISUSE
  );
  assert( (p->rc!=SQLITE_ROW && p->rc!=SQLITE_DONE) || p->rc==p->rcApp );
  if( p->isPrepareV2 && rc!=SQLITE_ROW && rc!=SQLITE_DONE ){
    /* If this statement was prepared using sqlite3_prepare_v2(), and an
    ** error has occurred, then return the error code in p->rc to the
    ** caller. Set the error code in the database handle to the same value.
    */ 

  zMod = pTab->azModuleArg[0];
  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);

  /* If the module has been registered and includes a Create method, 
  ** invoke it now. If the module has not been registered, return an 
  ** error. Otherwise, do nothing.
  */
  if( pMod==0 || pMod->pModule->xCreate==0 ){
    *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
    rc = SQLITE_ERROR;
  }else{
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
  }

  /* Justification of ALWAYS():  The xConstructor method is required to
................................................................................
int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
  int rc = SQLITE_OK;
  Table *pTab;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  if( ALWAYS(pTab!=0 && pTab->pVTable!=0) ){
    VTable *p;

    for(p=pTab->pVTable; p; p=p->pNext){
      assert( p->pVtab );
      if( p->pVtab->nRef>0 ){
        return SQLITE_LOCKED;
      }
    }
    p = vtabDisconnectAll(db, pTab);
    rc = p->pMod->pModule->xDestroy(p->pVtab);


    /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
    if( rc==SQLITE_OK ){
      assert( pTab->pVTable==p && p->pNext==0 );
      p->pVtab = 0;
      pTab->pVTable = 0;
      sqlite3VtabUnlock(p);
    }
................................................................................
  pTab->zName = (char*)&pTab[1];
  memcpy(pTab->zName, pMod->zName, nName);
  pTab->nRef = 1;
  pTab->pSchema = db->aDb[0].pSchema;
  pTab->tabFlags |= TF_Virtual;
  pTab->nModuleArg = 0;
  pTab->iPKey = -1;
  addModuleArgument(db, pTab, pTab->zName);
  addModuleArgument(db, pTab, 0);
  addModuleArgument(db, pTab, pTab->zName);
  rc = vtabCallConstructor(db, pTab, pMod, pModule->xConnect, &zErr);
  if( rc ){
    sqlite3ErrorMsg(pParse, "%s", zErr);
    sqlite3DbFree(db, zErr);
    sqlite3VtabEponymousTableClear(db, pMod);
    return 0;
  }
................................................................................
** Erase the eponymous virtual table instance associated with
** virtual table module pMod, if it exists.
*/
void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
  Table *pTab = pMod->pEpoTab;
  if( (pTab = pMod->pEpoTab)!=0 ){
    sqlite3DeleteColumnNames(db, pTab);
    sqlite3DbFree(db, pTab->azModuleArg);
    sqlite3DbFree(db, pTab);
    pMod->pEpoTab = 0;
  }
}

/*
** Return the ON CONFLICT resolution mode in effect for the virtual

  zMod = pTab->azModuleArg[0];
  pMod = (Module*)sqlite3HashFind(&db->aModule, zMod);

  /* If the module has been registered and includes a Create method, 
  ** invoke it now. If the module has not been registered, return an 
  ** error. Otherwise, do nothing.
  */
  if( pMod==0 || pMod->pModule->xCreate==0 || pMod->pModule->xDestroy==0 ){
    *pzErr = sqlite3MPrintf(db, "no such module: %s", zMod);
    rc = SQLITE_ERROR;
  }else{
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
  }

  /* Justification of ALWAYS():  The xConstructor method is required to
................................................................................
int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab){
  int rc = SQLITE_OK;
  Table *pTab;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  if( ALWAYS(pTab!=0 && pTab->pVTable!=0) ){
    VTable *p;
    int (*xDestroy)(sqlite3_vtab *);
    for(p=pTab->pVTable; p; p=p->pNext){
      assert( p->pVtab );
      if( p->pVtab->nRef>0 ){
        return SQLITE_LOCKED;
      }
    }
    p = vtabDisconnectAll(db, pTab);
    xDestroy = p->pMod->pModule->xDestroy;
    assert( xDestroy!=0 );  /* Checked before the virtual table is created */
    rc = xDestroy(p->pVtab);
    /* Remove the sqlite3_vtab* from the aVTrans[] array, if applicable */
    if( rc==SQLITE_OK ){
      assert( pTab->pVTable==p && p->pNext==0 );
      p->pVtab = 0;
      pTab->pVTable = 0;
      sqlite3VtabUnlock(p);
    }
................................................................................
  pTab->zName = (char*)&pTab[1];
  memcpy(pTab->zName, pMod->zName, nName);
  pTab->nRef = 1;
  pTab->pSchema = db->aDb[0].pSchema;
  pTab->tabFlags |= TF_Virtual;
  pTab->nModuleArg = 0;
  pTab->iPKey = -1;
  addModuleArgument(db, pTab, sqlite3DbStrDup(db, pTab->zName));
  addModuleArgument(db, pTab, 0);
  addModuleArgument(db, pTab, sqlite3DbStrDup(db, pTab->zName));
  rc = vtabCallConstructor(db, pTab, pMod, pModule->xConnect, &zErr);
  if( rc ){
    sqlite3ErrorMsg(pParse, "%s", zErr);
    sqlite3DbFree(db, zErr);
    sqlite3VtabEponymousTableClear(db, pMod);
    return 0;
  }
................................................................................
** Erase the eponymous virtual table instance associated with
** virtual table module pMod, if it exists.
*/
void sqlite3VtabEponymousTableClear(sqlite3 *db, Module *pMod){
  Table *pTab = pMod->pEpoTab;
  if( (pTab = pMod->pEpoTab)!=0 ){
    sqlite3DeleteColumnNames(db, pTab);
    sqlite3VtabClear(db, pTab);
    sqlite3DbFree(db, pTab);
    pMod->pEpoTab = 0;
  }
}

/*
** Return the ON CONFLICT resolution mode in effect for the virtual

  pTab = pItem->pTab;
  assert( pTab!=0 );
  pArgs = pItem->u1.pFuncArg;
  assert( pArgs!=0 );
  for(j=k=0; j<pArgs->nExpr; j++){
    while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){ k++; }
    if( k>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "too many arguments on %s - max %d",
                      pTab->zName, j);
      return;
    }
    pColRef = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
    if( pColRef==0 ) return;
    pColRef->iTable = pItem->iCursor;
    pColRef->iColumn = k++;
    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef,
                         sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
  }
}

  pTab = pItem->pTab;
  assert( pTab!=0 );
  pArgs = pItem->u1.pFuncArg;
  assert( pArgs!=0 );
  for(j=k=0; j<pArgs->nExpr; j++){
    while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){ k++; }
    if( k>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d",
                      pTab->zName, j);
      return;
    }
    pColRef = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
    if( pColRef==0 ) return;
    pColRef->iTable = pItem->iCursor;
    pColRef->iColumn = k++;
    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef,
                         sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
  }
}

  SELECT * FROM generate_series(1,9);
} {1 2 3 4 5 6 7 8 9}
do_execsql_test tabfunc01-1.6 {
  SELECT * FROM generate_series(1,10) WHERE step=3;
} {1 4 7 10}
do_catchsql_test tabfunc01-1.7 {
  SELECT * FROM generate_series(1,9,2,11);
} {1 {too many arguments on generate_series - max 3}}

do_execsql_test tabfunc01-1.8 {
  SELECT * FROM generate_series(0,32,5) ORDER BY rowid DESC;
} {30 25 20 15 10 5 0}
do_execsql_test tabfunc01-1.9 {
  SELECT rowid, * FROM generate_series(0,32,5) ORDER BY value DESC;
} {1 30 2 25 3 20 4 15 5 10 6 5 7 0}
................................................................................
} {7 30 6 25 5 20 4 15 3 10 2 5 1 0}

do_execsql_test tabfunc01-2.1 {
  CREATE TABLE t1(x);
  INSERT INTO t1(x) VALUES(2),(3);
  SELECT *, '|' FROM t1, generate_series(1,x) ORDER BY 1, 2
} {2 1 | 2 2 | 3 1 | 3 2 | 3 3 |}






finish_test

  SELECT * FROM generate_series(1,9);
} {1 2 3 4 5 6 7 8 9}
do_execsql_test tabfunc01-1.6 {
  SELECT * FROM generate_series(1,10) WHERE step=3;
} {1 4 7 10}
do_catchsql_test tabfunc01-1.7 {
  SELECT * FROM generate_series(1,9,2,11);
} {1 {too many arguments on generate_series() - max 3}}

do_execsql_test tabfunc01-1.8 {
  SELECT * FROM generate_series(0,32,5) ORDER BY rowid DESC;
} {30 25 20 15 10 5 0}
do_execsql_test tabfunc01-1.9 {
  SELECT rowid, * FROM generate_series(0,32,5) ORDER BY value DESC;
} {1 30 2 25 3 20 4 15 5 10 6 5 7 0}
................................................................................
} {7 30 6 25 5 20 4 15 3 10 2 5 1 0}

do_execsql_test tabfunc01-2.1 {
  CREATE TABLE t1(x);
  INSERT INTO t1(x) VALUES(2),(3);
  SELECT *, '|' FROM t1, generate_series(1,x) ORDER BY 1, 2
} {2 1 | 2 2 | 3 1 | 3 2 | 3 3 |}

do_execsql_test tabfunc01-2.2 {
  SELECT * FROM generate_series() LIMIT 5;
} {0 1 2 3 4}


finish_test

}

/*
** Advance the rolling hash by a single character "c"
*/
static void hash_next(hash *pHash, int c){
  u16 old = pHash->z[pHash->i];
  pHash->z[pHash->i] = c;
  pHash->i = (pHash->i+1)&(NHASH-1);
  pHash->a = pHash->a - old + c;
  pHash->b = pHash->b - NHASH*old + pHash->a;
}

/*
** Return a 32-bit hash value
*/
static u32 hash_32bit(hash *pHash){
................................................................................
}

/*
** Return the number digits in the base-64 representation of a positive integer
*/
static int digit_count(int v){
  unsigned int i, x;
  for(i=1, x=64; v>=x; i++, x <<= 6){}
  return i;
}

/*
** Compute a 32-bit checksum on the N-byte buffer.  Return the result.
*/
static unsigned int checksum(const char *zIn, size_t N){
................................................................................
static int rbuDeltaCreate(
  const char *zSrc,      /* The source or pattern file */
  unsigned int lenSrc,   /* Length of the source file */
  const char *zOut,      /* The target file */
  unsigned int lenOut,   /* Length of the target file */
  char *zDelta           /* Write the delta into this buffer */
){
  int i, base;
  char *zOrigDelta = zDelta;
  hash h;
  int nHash;                 /* Number of hash table entries */
  int *landmark;             /* Primary hash table */
  int *collide;              /* Collision chain */
  int lastRead = -1;         /* Last byte of zSrc read by a COPY command */

................................................................................

  /* Begin scanning the target file and generating copy commands and
  ** literal sections of the delta.
  */
  base = 0;    /* We have already generated everything before zOut[base] */
  while( base+NHASH<lenOut ){
    int iSrc, iBlock;
    unsigned int bestCnt, bestOfst=0, bestLitsz=0;
    hash_init(&h, &zOut[base]);
    i = 0;     /* Trying to match a landmark against zOut[base+i] */
    bestCnt = 0;
    while( 1 ){
      int hv;
      int limit = 250;

................................................................................
        int cnt, ofst, litsz;
        int j, k, x, y;
        int sz;

        /* Beginning at iSrc, match forwards as far as we can.  j counts
        ** the number of characters that match */
        iSrc = iBlock*NHASH;

        for(j=0, x=iSrc, y=base+i; x<lenSrc && y<lenOut; j++, x++, y++){



          if( zSrc[x]!=zOut[y] ) break;
        }
        j--;

        /* Beginning at iSrc-1, match backwards as far as we can.  k counts
        ** the number of characters that match */
        for(k=1; k<iSrc && k<=i; k++){
          if( zSrc[iSrc-k]!=zOut[base+i-k] ) break;
        }
        k--;

        /* Compute the offset and size of the matching region */
        ofst = iSrc-k;
        cnt = j+k+1;

}

/*
** Advance the rolling hash by a single character "c"
*/
static void hash_next(hash *pHash, int c){
  u16 old = pHash->z[pHash->i];
  pHash->z[pHash->i] = (char)c;
  pHash->i = (pHash->i+1)&(NHASH-1);
  pHash->a = pHash->a - old + (char)c;
  pHash->b = pHash->b - NHASH*old + pHash->a;
}

/*
** Return a 32-bit hash value
*/
static u32 hash_32bit(hash *pHash){
................................................................................
}

/*
** Return the number digits in the base-64 representation of a positive integer
*/
static int digit_count(int v){
  unsigned int i, x;
  for(i=1, x=64; (unsigned int)v>=x; i++, x <<= 6){}
  return i;
}

/*
** Compute a 32-bit checksum on the N-byte buffer.  Return the result.
*/
static unsigned int checksum(const char *zIn, size_t N){
................................................................................
static int rbuDeltaCreate(
  const char *zSrc,      /* The source or pattern file */
  unsigned int lenSrc,   /* Length of the source file */
  const char *zOut,      /* The target file */
  unsigned int lenOut,   /* Length of the target file */
  char *zDelta           /* Write the delta into this buffer */
){
  unsigned int i, base;
  char *zOrigDelta = zDelta;
  hash h;
  int nHash;                 /* Number of hash table entries */
  int *landmark;             /* Primary hash table */
  int *collide;              /* Collision chain */
  int lastRead = -1;         /* Last byte of zSrc read by a COPY command */

................................................................................

  /* Begin scanning the target file and generating copy commands and
  ** literal sections of the delta.
  */
  base = 0;    /* We have already generated everything before zOut[base] */
  while( base+NHASH<lenOut ){
    int iSrc, iBlock;
    int bestCnt, bestOfst=0, bestLitsz=0;
    hash_init(&h, &zOut[base]);
    i = 0;     /* Trying to match a landmark against zOut[base+i] */
    bestCnt = 0;
    while( 1 ){
      int hv;
      int limit = 250;

................................................................................
        int cnt, ofst, litsz;
        int j, k, x, y;
        int sz;

        /* Beginning at iSrc, match forwards as far as we can.  j counts
        ** the number of characters that match */
        iSrc = iBlock*NHASH;
        for(
          j=0, x=iSrc, y=base+i;
          (unsigned int)x<lenSrc && (unsigned int)y<lenOut;
          j++, x++, y++
        ){
          if( zSrc[x]!=zOut[y] ) break;
        }
        j--;

        /* Beginning at iSrc-1, match backwards as far as we can.  k counts
        ** the number of characters that match */
        for(k=1; k<iSrc && (unsigned int)k<=i; k++){
          if( zSrc[iSrc-k]!=zOut[base+i-k] ) break;
        }
        k--;

        /* Compute the offset and size of the matching region */
        ofst = iSrc-k;
        cnt = j+k+1;