Import SQLite 3.8.7.4.

third_party/sqlite/src/src/test_fuzzer.c

Index: third_party/sqlite/src/src/test_fuzzer.c
diff --git a/third_party/sqlite/src/src/test_fuzzer.c b/third_party/sqlite/src/src/test_fuzzer.c
deleted file mode 100644
index cf59257175a32bfaa2b9d69eb859a0824fb6194d..0000000000000000000000000000000000000000
--- a/third_party/sqlite/src/src/test_fuzzer.c
+++ /dev/null
@@ -1,944 +0,0 @@
-/*
-** 2011 March 24
-**
-** 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.
-**
-*************************************************************************
-**
-** Code for demonstartion virtual table that generates variations
-** on an input word at increasing edit distances from the original.
-**
-** A fuzzer virtual table is created like this:
-**
-**     CREATE VIRTUAL TABLE temp.f USING fuzzer;
-**
-** The name of the new virtual table in the example above is "f".
-** Note that all fuzzer virtual tables must be TEMP tables.  The
-** "temp." prefix in front of the table name is required when the
-** table is being created.  The "temp." prefix can be omitted when
-** using the table as long as the name is unambiguous.
-**
-** Before being used, the fuzzer needs to be programmed by giving it
-** character transformations and a cost associated with each transformation.
-** Examples:
-**
-**    INSERT INTO f(cFrom,cTo,Cost) VALUES('','a',100);
-**
-** The above statement says that the cost of inserting a letter 'a' is
-** 100.  (All costs are integers.  We recommend that costs be scaled so
-** that the average cost is around 100.)
-**
-**    INSERT INTO f(cFrom,cTo,Cost) VALUES('b','',87);
-**
-** The above statement says that the cost of deleting a single letter
-** 'b' is 87.
-**
-**    INSERT INTO f(cFrom,cTo,Cost) VALUES('o','oe',38);
-**    INSERT INTO f(cFrom,cTo,Cost) VALUES('oe','o',40);
-**
-** This third example says that the cost of transforming the single
-** letter "o" into the two-letter sequence "oe" is 38 and that the
-** cost of transforming "oe" back into "o" is 40.
-**
-** After all the transformation costs have been set, the fuzzer table
-** can be queried as follows:
-**
-**    SELECT word, distance FROM f
-**     WHERE word MATCH 'abcdefg'
-**       AND distance<200;
-**
-** This first query outputs the string "abcdefg" and all strings that
-** can be derived from that string by appling the specified transformations.
-** The strings are output together with their total transformation cost
-** (called "distance") and appear in order of increasing cost.  No string
-** is output more than once.  If there are multiple ways to transform the
-** target string into the output string then the lowest cost transform is
-** the one that is returned.  In the example, the search is limited to 
-** strings with a total distance of less than 200.
-**
-** It is important to put some kind of a limit on the fuzzer output.  This
-** can be either in the form of a LIMIT clause at the end of the query,
-** or better, a "distance<NNN" constraint where NNN is some number.  The
-** running time and memory requirement is exponential in the value of NNN 
-** so you want to make sure that NNN is not too big.  A value of NNN that
-** is about twice the average transformation cost seems to give good results.
-**
-** The fuzzer table can be useful for tasks such as spelling correction.
-** Suppose there is a second table vocabulary(w) where the w column contains
-** all correctly spelled words.   Let $word be a word you want to look up.
-**
-**   SELECT vocabulary.w FROM f, vocabulary
-**    WHERE f.word MATCH $word
-**      AND f.distance<=200
-**      AND f.word=vocabulary.w
-**    LIMIT 20
-**
-** The query above gives the 20 closest words to the $word being tested.
-** (Note that for good performance, the vocubulary.w column should be
-** indexed.)
-**
-** A similar query can be used to find all words in the dictionary that
-** begin with some prefix $prefix:
-**
-**   SELECT vocabulary.w FROM f, vocabulary
-**    WHERE f.word MATCH $prefix
-**      AND f.distance<=200
-**      AND vocabulary.w BETWEEN f.word AND (f.word || x'F7BFBFBF')
-**    LIMIT 50
-**
-** This last query will show up to 50 words out of the vocabulary that
-** match or nearly match the $prefix.
-*/
-#include "sqlite3.h"
-#include <stdlib.h>
-#include <string.h>
-#include <assert.h>
-#include <stdio.h>
-
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-
-/*
-** Forward declaration of objects used by this implementation
-*/
-typedef struct fuzzer_vtab fuzzer_vtab;
-typedef struct fuzzer_cursor fuzzer_cursor;
-typedef struct fuzzer_rule fuzzer_rule;
-typedef struct fuzzer_seen fuzzer_seen;
-typedef struct fuzzer_stem fuzzer_stem;
-
-/*
-** Type of the "cost" of an edit operation.  Might be changed to
-** "float" or "double" or "sqlite3_int64" in the future.
-*/
-typedef int fuzzer_cost;
-
-
-/*
-** Each transformation rule is stored as an instance of this object.
-** All rules are kept on a linked list sorted by rCost.
-*/
-struct fuzzer_rule {
-  fuzzer_rule *pNext;        /* Next rule in order of increasing rCost */
-  fuzzer_cost rCost;         /* Cost of this transformation */
-  int nFrom, nTo;            /* Length of the zFrom and zTo strings */
-  char *zFrom;               /* Transform from */
-  char zTo[4];               /* Transform to (extra space appended) */
-};
-
-/*
-** A stem object is used to generate variants.  It is also used to record
-** previously generated outputs.
-**
-** Every stem is added to a hash table as it is output.  Generation of
-** duplicate stems is suppressed.
-**
-** Active stems (those that might generate new outputs) are kepts on a linked
-** list sorted by increasing cost.  The cost is the sum of rBaseCost and
-** pRule->rCost.
-*/
-struct fuzzer_stem {
-  char *zBasis;              /* Word being fuzzed */
-  int nBasis;                /* Length of the zBasis string */
-  const fuzzer_rule *pRule;  /* Current rule to apply */
-  int n;                     /* Apply pRule at this character offset */
-  fuzzer_cost rBaseCost;     /* Base cost of getting to zBasis */
-  fuzzer_cost rCostX;        /* Precomputed rBaseCost + pRule->rCost */
-  fuzzer_stem *pNext;        /* Next stem in rCost order */
-  fuzzer_stem *pHash;        /* Next stem with same hash on zBasis */
-};
-
-/* 
-** A fuzzer virtual-table object 
-*/
-struct fuzzer_vtab {
-  sqlite3_vtab base;         /* Base class - must be first */
-  char *zClassName;          /* Name of this class.  Default: "fuzzer" */
-  fuzzer_rule *pRule;        /* All active rules in this fuzzer */
-  fuzzer_rule *pNewRule;     /* New rules to add when last cursor expires */
-  int nCursor;               /* Number of active cursors */
-};
-
-#define FUZZER_HASH  4001    /* Hash table size */
-#define FUZZER_NQUEUE  20    /* Number of slots on the stem queue */
-
-/* A fuzzer cursor object */
-struct fuzzer_cursor {
-  sqlite3_vtab_cursor base;  /* Base class - must be first */
-  sqlite3_int64 iRowid;      /* The rowid of the current word */
-  fuzzer_vtab *pVtab;        /* The virtual table this cursor belongs to */
-  fuzzer_cost rLimit;        /* Maximum cost of any term */
-  fuzzer_stem *pStem;        /* Stem with smallest rCostX */
-  fuzzer_stem *pDone;        /* Stems already processed to completion */
-  fuzzer_stem *aQueue[FUZZER_NQUEUE];  /* Queue of stems with higher rCostX */
-  int mxQueue;               /* Largest used index in aQueue[] */
-  char *zBuf;                /* Temporary use buffer */
-  int nBuf;                  /* Bytes allocated for zBuf */
-  int nStem;                 /* Number of stems allocated */
-  fuzzer_rule nullRule;      /* Null rule used first */
-  fuzzer_stem *apHash[FUZZER_HASH]; /* Hash of previously generated terms */
-};
-
-/* Methods for the fuzzer module */
-static int fuzzerConnect(
-  sqlite3 *db,
-  void *pAux,
-  int argc, const char *const*argv,
-  sqlite3_vtab **ppVtab,
-  char **pzErr
-){
-  fuzzer_vtab *pNew;
-  int n;
-  if( strcmp(argv[1],"temp")!=0 ){
-    *pzErr = sqlite3_mprintf("%s virtual tables must be TEMP", argv[0]);
-    return SQLITE_ERROR;
-  }
-  n = strlen(argv[0]) + 1;
-  pNew = sqlite3_malloc( sizeof(*pNew) + n );
-  if( pNew==0 ) return SQLITE_NOMEM;
-  pNew->zClassName = (char*)&pNew[1];
-  memcpy(pNew->zClassName, argv[0], n);
-  sqlite3_declare_vtab(db, "CREATE TABLE x(word,distance,cFrom,cTo,cost)");
-  memset(pNew, 0, sizeof(*pNew));
-  *ppVtab = &pNew->base;
-  return SQLITE_OK;
-}
-/* Note that for this virtual table, the xCreate and xConnect
-** methods are identical. */
-
-static int fuzzerDisconnect(sqlite3_vtab *pVtab){
-  fuzzer_vtab *p = (fuzzer_vtab*)pVtab;
-  assert( p->nCursor==0 );
-  do{
-    while( p->pRule ){
-      fuzzer_rule *pRule = p->pRule;
-      p->pRule = pRule->pNext;
-      sqlite3_free(pRule);
-    }
-    p->pRule = p->pNewRule;
-    p->pNewRule = 0;
-  }while( p->pRule );
-  sqlite3_free(p);
-  return SQLITE_OK;
-}
-/* The xDisconnect and xDestroy methods are also the same */
-
-/*
-** The two input rule lists are both sorted in order of increasing
-** cost.  Merge them together into a single list, sorted by cost, and
-** return a pointer to the head of that list.
-*/
-static fuzzer_rule *fuzzerMergeRules(fuzzer_rule *pA, fuzzer_rule *pB){
-  fuzzer_rule head;
-  fuzzer_rule *pTail;
-
-  pTail =  &head;
-  while( pA && pB ){
-    if( pA->rCost<=pB->rCost ){
-      pTail->pNext = pA;
-      pTail = pA;
-      pA = pA->pNext;
-    }else{
-      pTail->pNext = pB;
-      pTail = pB;
-      pB = pB->pNext;
-    }
-  }
-  if( pA==0 ){
-    pTail->pNext = pB;
-  }else{
-    pTail->pNext = pA;
-  }
-  return head.pNext;
-}
-
-
-/*
-** Open a new fuzzer cursor.
-*/
-static int fuzzerOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
-  fuzzer_vtab *p = (fuzzer_vtab*)pVTab;
-  fuzzer_cursor *pCur;
-  pCur = sqlite3_malloc( sizeof(*pCur) );
-  if( pCur==0 ) return SQLITE_NOMEM;
-  memset(pCur, 0, sizeof(*pCur));
-  pCur->pVtab = p;
-  *ppCursor = &pCur->base;
-  if( p->nCursor==0 && p->pNewRule ){
-    unsigned int i;
-    fuzzer_rule *pX;
-    fuzzer_rule *a[15];
-    for(i=0; i<sizeof(a)/sizeof(a[0]); i++) a[i] = 0;
-    while( (pX = p->pNewRule)!=0 ){
-      p->pNewRule = pX->pNext;
-      pX->pNext = 0;
-      for(i=0; a[i] && i<sizeof(a)/sizeof(a[0])-1; i++){
-        pX = fuzzerMergeRules(a[i], pX);
-        a[i] = 0;
-      }
-      a[i] = fuzzerMergeRules(a[i], pX);
-    }
-    for(pX=a[0], i=1; i<sizeof(a)/sizeof(a[0]); i++){
-      pX = fuzzerMergeRules(a[i], pX);
-    }
-    p->pRule = fuzzerMergeRules(p->pRule, pX);
-  }
-  p->nCursor++;
-  return SQLITE_OK;
-}
-
-/*
-** Free all stems in a list.
-*/
-static void fuzzerClearStemList(fuzzer_stem *pStem){
-  while( pStem ){
-    fuzzer_stem *pNext = pStem->pNext;
-    sqlite3_free(pStem);
-    pStem = pNext;
-  }
-}
-
-/*
-** Free up all the memory allocated by a cursor.  Set it rLimit to 0
-** to indicate that it is at EOF.
-*/
-static void fuzzerClearCursor(fuzzer_cursor *pCur, int clearHash){
-  int i;
-  fuzzerClearStemList(pCur->pStem);
-  fuzzerClearStemList(pCur->pDone);
-  for(i=0; i<FUZZER_NQUEUE; i++) fuzzerClearStemList(pCur->aQueue[i]);
-  pCur->rLimit = (fuzzer_cost)0;
-  if( clearHash && pCur->nStem ){
-    pCur->mxQueue = 0;
-    pCur->pStem = 0;
-    pCur->pDone = 0;
-    memset(pCur->aQueue, 0, sizeof(pCur->aQueue));
-    memset(pCur->apHash, 0, sizeof(pCur->apHash));
-  }
-  pCur->nStem = 0;
-}
-
-/*
-** Close a fuzzer cursor.
-*/
-static int fuzzerClose(sqlite3_vtab_cursor *cur){
-  fuzzer_cursor *pCur = (fuzzer_cursor *)cur;
-  fuzzerClearCursor(pCur, 0);
-  sqlite3_free(pCur->zBuf);
-  pCur->pVtab->nCursor--;
-  sqlite3_free(pCur);
-  return SQLITE_OK;
-}
-
-/*
-** Compute the current output term for a fuzzer_stem.
-*/
-static int fuzzerRender(
-  fuzzer_stem *pStem,   /* The stem to be rendered */
-  char **pzBuf,         /* Write results into this buffer.  realloc if needed */
-  int *pnBuf            /* Size of the buffer */
-){
-  const fuzzer_rule *pRule = pStem->pRule;
-  int n;
-  char *z;
-
-  n = pStem->nBasis + pRule->nTo - pRule->nFrom;
-  if( (*pnBuf)<n+1 ){
-    (*pzBuf) = sqlite3_realloc((*pzBuf), n+100);
-    if( (*pzBuf)==0 ) return SQLITE_NOMEM;
-    (*pnBuf) = n+100;
-  }
-  n = pStem->n;
-  z = *pzBuf;
-  if( n<0 ){
-    memcpy(z, pStem->zBasis, pStem->nBasis+1);
-  }else{
-    memcpy(z, pStem->zBasis, n);
-    memcpy(&z[n], pRule->zTo, pRule->nTo);
-    memcpy(&z[n+pRule->nTo], &pStem->zBasis[n+pRule->nFrom], 
-           pStem->nBasis-n-pRule->nFrom+1);
-  }
-  return SQLITE_OK;
-}
-
-/*
-** Compute a hash on zBasis.
-*/
-static unsigned int fuzzerHash(const char *z){
-  unsigned int h = 0;
-  while( *z ){ h = (h<<3) ^ (h>>29) ^ *(z++); }
-  return h % FUZZER_HASH;
-}
-
-/*
-** Current cost of a stem
-*/
-static fuzzer_cost fuzzerCost(fuzzer_stem *pStem){
-  return pStem->rCostX = pStem->rBaseCost + pStem->pRule->rCost;
-}
-
-#if 0
-/*
-** Print a description of a fuzzer_stem on stderr.
-*/
-static void fuzzerStemPrint(
-  const char *zPrefix,
-  fuzzer_stem *pStem,
-  const char *zSuffix
-){
-  if( pStem->n<0 ){
-    fprintf(stderr, "%s[%s](%d)-->self%s",
-       zPrefix,
-       pStem->zBasis, pStem->rBaseCost,
-       zSuffix
-    );
-  }else{
-    char *zBuf = 0;
-    int nBuf = 0;
-    if( fuzzerRender(pStem, &zBuf, &nBuf)!=SQLITE_OK ) return;
-    fprintf(stderr, "%s[%s](%d)-->{%s}(%d)%s",
-      zPrefix,
-      pStem->zBasis, pStem->rBaseCost, zBuf, pStem->,
-      zSuffix
-    );
-    sqlite3_free(zBuf);
-  }
-}
-#endif
-
-/*
-** Return 1 if the string to which the cursor is point has already
-** been emitted.  Return 0 if not.  Return -1 on a memory allocation
-** failures.
-*/
-static int fuzzerSeen(fuzzer_cursor *pCur, fuzzer_stem *pStem){
-  unsigned int h;
-  fuzzer_stem *pLookup;
-
-  if( fuzzerRender(pStem, &pCur->zBuf, &pCur->nBuf)==SQLITE_NOMEM ){
-    return -1;
-  }
-  h = fuzzerHash(pCur->zBuf);
-  pLookup = pCur->apHash[h];
-    while( pLookup && strcmp(pLookup->zBasis, pCur->zBuf)!=0 ){
-    pLookup = pLookup->pHash;
-  }
-  return pLookup!=0;
-}
-
-/*
-** Advance a fuzzer_stem to its next value.   Return 0 if there are
-** no more values that can be generated by this fuzzer_stem.  Return
-** -1 on a memory allocation failure.
-*/
-static int fuzzerAdvance(fuzzer_cursor *pCur, fuzzer_stem *pStem){
-  const fuzzer_rule *pRule;
-  while( (pRule = pStem->pRule)!=0 ){
-    while( pStem->n < pStem->nBasis - pRule->nFrom ){
-      pStem->n++;
-      if( pRule->nFrom==0
-       || memcmp(&pStem->zBasis[pStem->n], pRule->zFrom, pRule->nFrom)==0
-      ){
-        /* Found a rewrite case.  Make sure it is not a duplicate */
-        int rc = fuzzerSeen(pCur, pStem);
-        if( rc<0 ) return -1;
-        if( rc==0 ){
-          fuzzerCost(pStem);
-          return 1;
-        }
-      }
-    }
-    pStem->n = -1;
-    pStem->pRule = pRule->pNext;
-    if( pStem->pRule && fuzzerCost(pStem)>pCur->rLimit ) pStem->pRule = 0;
-  }
-  return 0;
-}
-
-/*
-** The two input stem lists are both sorted in order of increasing
-** rCostX.  Merge them together into a single list, sorted by rCostX, and
-** return a pointer to the head of that new list.
-*/
-static fuzzer_stem *fuzzerMergeStems(fuzzer_stem *pA, fuzzer_stem *pB){
-  fuzzer_stem head;
-  fuzzer_stem *pTail;
-
-  pTail =  &head;
-  while( pA && pB ){
-    if( pA->rCostX<=pB->rCostX ){
-      pTail->pNext = pA;
-      pTail = pA;
-      pA = pA->pNext;
-    }else{
-      pTail->pNext = pB;
-      pTail = pB;
-      pB = pB->pNext;
-    }
-  }
-  if( pA==0 ){
-    pTail->pNext = pB;
-  }else{
-    pTail->pNext = pA;
-  }
-  return head.pNext;
-}
-
-/*
-** Load pCur->pStem with the lowest-cost stem.  Return a pointer
-** to the lowest-cost stem.
-*/
-static fuzzer_stem *fuzzerLowestCostStem(fuzzer_cursor *pCur){
-  fuzzer_stem *pBest, *pX;
-  int iBest;
-  int i;
-
-  if( pCur->pStem==0 ){
-    iBest = -1;
-    pBest = 0;
-    for(i=0; i<=pCur->mxQueue; i++){
-      pX = pCur->aQueue[i];
-      if( pX==0 ) continue;
-      if( pBest==0 || pBest->rCostX>pX->rCostX ){
-        pBest = pX;
-        iBest = i;
-      }
-    } 
-    if( pBest ){
-      pCur->aQueue[iBest] = pBest->pNext;
-      pBest->pNext = 0;
-      pCur->pStem = pBest;
-    }
-  }
-  return pCur->pStem;
-}
-
-/*
-** Insert pNew into queue of pending stems.  Then find the stem
-** with the lowest rCostX and move it into pCur->pStem.
-** list.  The insert is done such the pNew is in the correct order
-** according to fuzzer_stem.zBaseCost+fuzzer_stem.pRule->rCost.
-*/
-static fuzzer_stem *fuzzerInsert(fuzzer_cursor *pCur, fuzzer_stem *pNew){
-  fuzzer_stem *pX;
-  int i;
-
-  /* If pCur->pStem exists and is greater than pNew, then make pNew
-  ** the new pCur->pStem and insert the old pCur->pStem instead.
-  */
-  if( (pX = pCur->pStem)!=0 && pX->rCostX>pNew->rCostX ){
-    pNew->pNext = 0;
-    pCur->pStem = pNew;
-    pNew = pX;
-  }
-
-  /* Insert the new value */
-  pNew->pNext = 0;
-  pX = pNew;
-  for(i=0; i<=pCur->mxQueue; i++){
-    if( pCur->aQueue[i] ){
-      pX = fuzzerMergeStems(pX, pCur->aQueue[i]);
-      pCur->aQueue[i] = 0;
-    }else{
-      pCur->aQueue[i] = pX;
-      break;
-    }
-  }
-  if( i>pCur->mxQueue ){
-    if( i<FUZZER_NQUEUE ){
-      pCur->mxQueue = i;
-      pCur->aQueue[i] = pX;
-    }else{
-      assert( pCur->mxQueue==FUZZER_NQUEUE-1 );
-      pX = fuzzerMergeStems(pX, pCur->aQueue[FUZZER_NQUEUE-1]);
-      pCur->aQueue[FUZZER_NQUEUE-1] = pX;
-    }
-  }
-
-  return fuzzerLowestCostStem(pCur);
-}
-
-/*
-** Allocate a new fuzzer_stem.  Add it to the hash table but do not
-** link it into either the pCur->pStem or pCur->pDone lists.
-*/
-static fuzzer_stem *fuzzerNewStem(
-  fuzzer_cursor *pCur,
-  const char *zWord,
-  fuzzer_cost rBaseCost
-){
-  fuzzer_stem *pNew;
-  unsigned int h;
-
-  pNew = sqlite3_malloc( sizeof(*pNew) + strlen(zWord) + 1 );
-  if( pNew==0 ) return 0;
-  memset(pNew, 0, sizeof(*pNew));
-  pNew->zBasis = (char*)&pNew[1];
-  pNew->nBasis = strlen(zWord);
-  memcpy(pNew->zBasis, zWord, pNew->nBasis+1);
-  pNew->pRule = pCur->pVtab->pRule;
-  pNew->n = -1;
-  pNew->rBaseCost = pNew->rCostX = rBaseCost;
-  h = fuzzerHash(pNew->zBasis);
-  pNew->pHash = pCur->apHash[h];
-  pCur->apHash[h] = pNew;
-  pCur->nStem++;
-  return pNew;
-}
-
-
-/*
-** Advance a cursor to its next row of output
-*/
-static int fuzzerNext(sqlite3_vtab_cursor *cur){
-  fuzzer_cursor *pCur = (fuzzer_cursor*)cur;
-  int rc;
-  fuzzer_stem *pStem, *pNew;
-
-  pCur->iRowid++;
-
-  /* Use the element the cursor is currently point to to create
-  ** a new stem and insert the new stem into the priority queue.
-  */
-  pStem = pCur->pStem;
-  if( pStem->rCostX>0 ){
-    rc = fuzzerRender(pStem, &pCur->zBuf, &pCur->nBuf);
-    if( rc==SQLITE_NOMEM ) return SQLITE_NOMEM;
-    pNew = fuzzerNewStem(pCur, pCur->zBuf, pStem->rCostX);
-    if( pNew ){
-      if( fuzzerAdvance(pCur, pNew)==0 ){
-        pNew->pNext = pCur->pDone;
-        pCur->pDone = pNew;
-      }else{
-        if( fuzzerInsert(pCur, pNew)==pNew ){
-          return SQLITE_OK;
-        }
-      }
-    }else{
-      return SQLITE_NOMEM;
-    }
-  }
-
-  /* Adjust the priority queue so that the first element of the
-  ** stem list is the next lowest cost word.
-  */
-  while( (pStem = pCur->pStem)!=0 ){
-    if( fuzzerAdvance(pCur, pStem) ){
-      pCur->pStem = 0;
-      pStem = fuzzerInsert(pCur, pStem);
-      if( (rc = fuzzerSeen(pCur, pStem))!=0 ){
-        if( rc<0 ) return SQLITE_NOMEM;
-        continue;
-      }
-      return SQLITE_OK;  /* New word found */
-    }
-    pCur->pStem = 0;
-    pStem->pNext = pCur->pDone;
-    pCur->pDone = pStem;
-    if( fuzzerLowestCostStem(pCur) ){
-      rc = fuzzerSeen(pCur, pCur->pStem);
-      if( rc<0 ) return SQLITE_NOMEM;
-      if( rc==0 ){
-        return SQLITE_OK;
-      }
-    }
-  }
-
-  /* Reach this point only if queue has been exhausted and there is
-  ** nothing left to be output. */
-  pCur->rLimit = (fuzzer_cost)0;
-  return SQLITE_OK;
-}
-
-/*
-** Called to "rewind" a cursor back to the beginning so that
-** it starts its output over again.  Always called at least once
-** prior to any fuzzerColumn, fuzzerRowid, or fuzzerEof call.
-*/
-static int fuzzerFilter(
-  sqlite3_vtab_cursor *pVtabCursor, 
-  int idxNum, const char *idxStr,
-  int argc, sqlite3_value **argv
-){
-  fuzzer_cursor *pCur = (fuzzer_cursor *)pVtabCursor;
-  const char *zWord = 0;
-  fuzzer_stem *pStem;
-
-  fuzzerClearCursor(pCur, 1);
-  pCur->rLimit = 2147483647;
-  if( idxNum==1 ){
-    zWord = (const char*)sqlite3_value_text(argv[0]);
-  }else if( idxNum==2 ){
-    pCur->rLimit = (fuzzer_cost)sqlite3_value_int(argv[0]);
-  }else if( idxNum==3 ){
-    zWord = (const char*)sqlite3_value_text(argv[0]);
-    pCur->rLimit = (fuzzer_cost)sqlite3_value_int(argv[1]);
-  }
-  if( zWord==0 ) zWord = "";
-  pCur->pStem = pStem = fuzzerNewStem(pCur, zWord, (fuzzer_cost)0);
-  if( pStem==0 ) return SQLITE_NOMEM;
-  pCur->nullRule.pNext = pCur->pVtab->pRule;
-  pCur->nullRule.rCost = 0;
-  pCur->nullRule.nFrom = 0;
-  pCur->nullRule.nTo = 0;
-  pCur->nullRule.zFrom = "";
-  pStem->pRule = &pCur->nullRule;
-  pStem->n = pStem->nBasis;
-  pCur->iRowid = 1;
-  return SQLITE_OK;
-}
-
-/*
-** Only the word and distance columns have values.  All other columns
-** return NULL
-*/
-static int fuzzerColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
-  fuzzer_cursor *pCur = (fuzzer_cursor*)cur;
-  if( i==0 ){
-    /* the "word" column */
-    if( fuzzerRender(pCur->pStem, &pCur->zBuf, &pCur->nBuf)==SQLITE_NOMEM ){
-      return SQLITE_NOMEM;
-    }
-    sqlite3_result_text(ctx, pCur->zBuf, -1, SQLITE_TRANSIENT);
-  }else if( i==1 ){
-    /* the "distance" column */
-    sqlite3_result_int(ctx, pCur->pStem->rCostX);
-  }else{
-    /* All other columns are NULL */
-    sqlite3_result_null(ctx);
-  }
-  return SQLITE_OK;
-}
-
-/*
-** The rowid.
-*/
-static int fuzzerRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
-  fuzzer_cursor *pCur = (fuzzer_cursor*)cur;
-  *pRowid = pCur->iRowid;
-  return SQLITE_OK;
-}
-
-/*
-** When the fuzzer_cursor.rLimit value is 0 or less, that is a signal
-** that the cursor has nothing more to output.
-*/
-static int fuzzerEof(sqlite3_vtab_cursor *cur){
-  fuzzer_cursor *pCur = (fuzzer_cursor*)cur;
-  return pCur->rLimit<=(fuzzer_cost)0;
-}
-
-/*
-** Search for terms of these forms:
-**
-**       word MATCH $str
-**       distance < $value
-**       distance <= $value
-**
-** The distance< and distance<= are both treated as distance<=.
-** The query plan number is as follows:
-**
-**   0:    None of the terms above are found
-**   1:    There is a "word MATCH" term with $str in filter.argv[0].
-**   2:    There is a "distance<" term with $value in filter.argv[0].
-**   3:    Both "word MATCH" and "distance<" with $str in argv[0] and
-**         $value in argv[1].
-*/
-static int fuzzerBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
-  int iPlan = 0;
-  int iDistTerm = -1;
-  int i;
-  const struct sqlite3_index_constraint *pConstraint;
-  pConstraint = pIdxInfo->aConstraint;
-  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
-    if( pConstraint->usable==0 ) continue;
-    if( (iPlan & 1)==0 
-     && pConstraint->iColumn==0
-     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH
-    ){
-      iPlan |= 1;
-      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
-      pIdxInfo->aConstraintUsage[i].omit = 1;
-    }
-    if( (iPlan & 2)==0
-     && pConstraint->iColumn==1
-     && (pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT
-           || pConstraint->op==SQLITE_INDEX_CONSTRAINT_LE)
-    ){
-      iPlan |= 2;
-      iDistTerm = i;
-    }
-  }
-  if( iPlan==2 ){
-    pIdxInfo->aConstraintUsage[iDistTerm].argvIndex = 1;
-  }else if( iPlan==3 ){
-    pIdxInfo->aConstraintUsage[iDistTerm].argvIndex = 2;
-  }
-  pIdxInfo->idxNum = iPlan;
-  if( pIdxInfo->nOrderBy==1
-   && pIdxInfo->aOrderBy[0].iColumn==1
-   && pIdxInfo->aOrderBy[0].desc==0
-  ){
-    pIdxInfo->orderByConsumed = 1;
-  }
-  pIdxInfo->estimatedCost = (double)10000;
-   
-  return SQLITE_OK;
-}
-
-/*
-** Disallow all attempts to DELETE or UPDATE.  Only INSERTs are allowed.
-**
-** On an insert, the cFrom, cTo, and cost columns are used to construct
-** a new rule.   All other columns are ignored.  The rule is ignored
-** if cFrom and cTo are identical.  A NULL value for cFrom or cTo is
-** interpreted as an empty string.  The cost must be positive.
-*/
-static int fuzzerUpdate(
-  sqlite3_vtab *pVTab,
-  int argc,
-  sqlite3_value **argv,
-  sqlite_int64 *pRowid
-){
-  fuzzer_vtab *p = (fuzzer_vtab*)pVTab;
-  fuzzer_rule *pRule;
-  const char *zFrom;
-  int nFrom;
-  const char *zTo;
-  int nTo;
-  fuzzer_cost rCost;
-  if( argc!=7 ){
-    sqlite3_free(pVTab->zErrMsg);
-    pVTab->zErrMsg = sqlite3_mprintf("cannot delete from a %s virtual table",
-                                     p->zClassName);
-    return SQLITE_CONSTRAINT;
-  }
-  if( sqlite3_value_type(argv[0])!=SQLITE_NULL ){
-    sqlite3_free(pVTab->zErrMsg);
-    pVTab->zErrMsg = sqlite3_mprintf("cannot update a %s virtual table",
-                                     p->zClassName);
-    return SQLITE_CONSTRAINT;
-  }
-  zFrom = (char*)sqlite3_value_text(argv[4]);
-  if( zFrom==0 ) zFrom = "";
-  zTo = (char*)sqlite3_value_text(argv[5]);
-  if( zTo==0 ) zTo = "";
-  if( strcmp(zFrom,zTo)==0 ){
-    /* Silently ignore null transformations */
-    return SQLITE_OK;
-  }
-  rCost = sqlite3_value_int(argv[6]);
-  if( rCost<=0 ){
-    sqlite3_free(pVTab->zErrMsg);
-    pVTab->zErrMsg = sqlite3_mprintf("cost must be positive");
-    return SQLITE_CONSTRAINT;    
-  }
-  nFrom = strlen(zFrom);
-  nTo = strlen(zTo);
-  pRule = sqlite3_malloc( sizeof(*pRule) + nFrom + nTo );
-  if( pRule==0 ){
-    return SQLITE_NOMEM;
-  }
-  pRule->zFrom = &pRule->zTo[nTo+1];
-  pRule->nFrom = nFrom;
-  memcpy(pRule->zFrom, zFrom, nFrom+1);
-  memcpy(pRule->zTo, zTo, nTo+1);
-  pRule->nTo = nTo;
-  pRule->rCost = rCost;
-  pRule->pNext = p->pNewRule;
-  p->pNewRule = pRule;
-  return SQLITE_OK;
-}
-
-/*
-** A virtual table module that provides read-only access to a
-** Tcl global variable namespace.
-*/
-static sqlite3_module fuzzerModule = {
-  0,                           /* iVersion */
-  fuzzerConnect,
-  fuzzerConnect,
-  fuzzerBestIndex,
-  fuzzerDisconnect, 
-  fuzzerDisconnect,
-  fuzzerOpen,                  /* xOpen - open a cursor */
-  fuzzerClose,                 /* xClose - close a cursor */
-  fuzzerFilter,                /* xFilter - configure scan constraints */
-  fuzzerNext,                  /* xNext - advance a cursor */
-  fuzzerEof,                   /* xEof - check for end of scan */
-  fuzzerColumn,                /* xColumn - read data */
-  fuzzerRowid,                 /* xRowid - read data */
-  fuzzerUpdate,                /* xUpdate - INSERT */
-  0,                           /* xBegin */
-  0,                           /* xSync */
-  0,                           /* xCommit */
-  0,                           /* xRollback */
-  0,                           /* xFindMethod */
-  0,                           /* xRename */
-};
-
-#endif /* SQLITE_OMIT_VIRTUALTABLE */
-
-
-/*
-** Register the fuzzer virtual table
-*/
-int fuzzer_register(sqlite3 *db){
-  int rc = SQLITE_OK;
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-  rc = sqlite3_create_module(db, "fuzzer", &fuzzerModule, 0);
-#endif
-  return rc;
-}
-
-#ifdef SQLITE_TEST
-#include <tcl.h>
-/*
-** Decode a pointer to an sqlite3 object.
-*/
-extern int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb);
-
-/*
-** Register the echo virtual table module.
-*/
-static int register_fuzzer_module(
-  ClientData clientData, /* Pointer to sqlite3_enable_XXX function */
-  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
-  int objc,              /* Number of arguments */
-  Tcl_Obj *CONST objv[]  /* Command arguments */
-){
-  sqlite3 *db;
-  if( objc!=2 ){
-    Tcl_WrongNumArgs(interp, 1, objv, "DB");
-    return TCL_ERROR;
-  }
-  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
-  fuzzer_register(db);
-  return TCL_OK;
-}
-
-
-/*
-** Register commands with the TCL interpreter.
-*/
-int Sqlitetestfuzzer_Init(Tcl_Interp *interp){
-  static struct {
-     char *zName;
-     Tcl_ObjCmdProc *xProc;
-     void *clientData;
-  } aObjCmd[] = {
-     { "register_fuzzer_module",   register_fuzzer_module, 0 },
-  };
-  int i;
-  for(i=0; i<sizeof(aObjCmd)/sizeof(aObjCmd[0]); i++){
-    Tcl_CreateObjCommand(interp, aObjCmd[i].zName, 
-        aObjCmd[i].xProc, aObjCmd[i].clientData, 0);
-  }
-  return TCL_OK;
-}
-
-#endif /* SQLITE_TEST */