From: dan <dan@noemail.net>
Date: Thu, 3 Jul 2014 20:39:39 +0000 (+0000)
Subject: Add support for NEAR expressions to fts5.
X-Git-Tag: version-3.8.11~114^2~171
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c18a8fe99c3d6e8ad316ecac66b961a5a9dcb996;p=thirdparty%2Fsqlite.git

Add support for NEAR expressions to fts5.

FossilOrigin-Name: 250ae8d40115e2e47cc5a1e8a427fa8c0a89124d
---

diff --git a/ext/fts5/fts5_expr.c b/ext/fts5/fts5_expr.c
index 1c0e936cb0..5a29f04709 100644
--- a/ext/fts5/fts5_expr.c
+++ b/ext/fts5/fts5_expr.c
@@ -69,7 +69,6 @@ struct Fts5ExprTerm {
 */
 struct Fts5ExprPhrase {
   Fts5Buffer poslist;             /* Current position list */
-  i64 iRowid;                     /* Current rowid */
   int nTerm;                      /* Number of entries in aTerm[] */
   Fts5ExprTerm aTerm[0];          /* Terms that make up this phrase */
 };
@@ -109,7 +108,7 @@ struct Fts5PoslistIter {
   i64 iPos;                       /* (iCol<<32) + iPos */
 };
 
-static void fts5PoslistIterNext(Fts5PoslistIter *pIter){
+static int fts5PoslistIterNext(Fts5PoslistIter *pIter){
   if( pIter->i>=pIter->n ){
     pIter->bEof = 1;
   }else{
@@ -122,6 +121,7 @@ static void fts5PoslistIterNext(Fts5PoslistIter *pIter){
     }
     pIter->iPos += (iVal-2);
   }
+  return pIter->bEof;
 }
 
 static void fts5PoslistIterInit(const u8 *a, int n, Fts5PoslistIter *pIter){
@@ -130,6 +130,32 @@ static void fts5PoslistIterInit(const u8 *a, int n, Fts5PoslistIter *pIter){
   pIter->n = n;
   fts5PoslistIterNext(pIter);
 }
+
+typedef struct Fts5PoslistWriter Fts5PoslistWriter;
+struct Fts5PoslistWriter {
+  int iCol;
+  int iOff;
+};
+
+static int fts5PoslistWriterAppend(
+  Fts5Buffer *pBuf, 
+  Fts5PoslistWriter *pWriter,
+  i64 iPos
+){
+  int rc = SQLITE_OK;
+  int iCol = (int)(iPos >> 32);
+  int iOff = (iPos & 0x7FFFFFFF);
+
+  if( iCol!=pWriter->iCol ){
+    fts5BufferAppendVarint(&rc, pBuf, 1);
+    fts5BufferAppendVarint(&rc, pBuf, iCol);
+    pWriter->iCol = iCol;
+    pWriter->iOff = 0;
+  }
+  fts5BufferAppendVarint(&rc, pBuf, (iOff - pWriter->iOff) + 2);
+
+  return rc;
+}
 /*
 *************************************************************************/
 
@@ -302,11 +328,14 @@ static int fts5ExprPhraseIsMatch(
   Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
   int *pbMatch                    /* OUT: Set to true if really a match */
 ){
+  Fts5PoslistWriter writer = {0, 0};
   Fts5PoslistIter aStatic[4];
   Fts5PoslistIter *aIter = aStatic;
   int i;
   int rc = SQLITE_OK;
 
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
   if( pPhrase->nTerm>(sizeof(aStatic) / sizeof(aStatic[0])) ){
     int nByte = sizeof(Fts5PoslistIter) * pPhrase->nTerm;
     aIter = (Fts5PoslistIter*)sqlite3_malloc(nByte);
@@ -320,108 +349,189 @@ static int fts5ExprPhraseIsMatch(
     fts5PoslistIterInit(a, n, &aIter[i]);
   }
 
-  *pbMatch = 0;
+  fts5BufferZero(&pPhrase->poslist);
   while( 1 ){
-
-    int bMatch = 1;
+    int bMatch;
     i64 iPos = aIter[0].iPos;
-    for(i=1; i<pPhrase->nTerm; i++){
-      Fts5PoslistIter *pPos = &aIter[i];
-      i64 iAdj = pPos->iPos-i;
-      if( (pPos->iPos-i)!=iPos ){
-        bMatch = 0;
-        if( iAdj>iPos ) iPos = iAdj;
+    do {
+      bMatch = 1;
+      for(i=0; i<pPhrase->nTerm; i++){
+        Fts5PoslistIter *pPos = &aIter[i];
+        i64 iAdj = iPos + i;
+        if( pPos->iPos!=iAdj ){
+          bMatch = 0;
+          while( pPos->iPos<iAdj ){
+            if( fts5PoslistIterNext(pPos) ) goto ismatch_out;
+          }
+          if( pPos->iPos>iAdj ) iPos = pPos->iPos-i;
+        }
       }
-    }
-    if( bMatch ){
-      *pbMatch = 1;
-      break;
-    }
+    }while( bMatch==0 );
+
+    /* Append position iPos to the output */
+    rc = fts5PoslistWriterAppend(&pPhrase->poslist, &writer, iPos);
+    if( rc!=SQLITE_OK ) goto ismatch_out;
 
     for(i=0; i<pPhrase->nTerm; i++){
+      if( fts5PoslistIterNext(&aIter[i]) ) goto ismatch_out;
+    }
+  }
+
+ ismatch_out:
+  *pbMatch = (pPhrase->poslist.n>0);
+  if( aIter!=aStatic ) sqlite3_free(aIter);
+  return rc;
+}
+
+
+static int fts5ExprNearIsMatch(Fts5ExprNearset *pNear, int *pbMatch){
+  Fts5PoslistIter aStatic[4];
+  Fts5PoslistIter *aIter = aStatic;
+  int i;
+  int rc = SQLITE_OK;
+  int bMatch;
+  i64 iMax;
+
+  /* If the aStatic[] array is not large enough, allocate a large array
+  ** using sqlite3_malloc(). This approach could be improved upon. */
+  if( pNear->nPhrase>(sizeof(aStatic) / sizeof(aStatic[0])) ){
+    int nByte = sizeof(Fts5PoslistIter) * pNear->nPhrase;
+    aIter = (Fts5PoslistIter*)sqlite3_malloc(nByte);
+    if( !aIter ) return SQLITE_NOMEM;
+  }
+
+  /* Initialize a term iterator for each phrase */
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5Buffer *pPoslist = &pNear->apPhrase[i]->poslist; 
+    fts5PoslistIterInit(pPoslist->p, pPoslist->n, &aIter[i]);
+  }
+
+  iMax = aIter[0].iPos;
+  do {
+    bMatch = 1;
+    for(i=0; i<pNear->nPhrase; i++){
       Fts5PoslistIter *pPos = &aIter[i];
-      while( (pPos->iPos-i) < iPos ){
-        fts5PoslistIterNext(pPos);
-        if( pPos->bEof ) goto ismatch_out;
+      i64 iMin = iMax - pNear->apPhrase[i]->nTerm - pNear->nNear;
+      if( pPos->iPos<iMin || pPos->iPos>iMax ){
+        bMatch = 0;
+        while( pPos->iPos<iMin ){
+          if( fts5PoslistIterNext(pPos) ) goto ismatch_out;
+        }
+        if( pPos->iPos>iMax ) iMax = pPos->iPos;
       }
     }
-  }
+  }while( bMatch==0 );
 
  ismatch_out:
+  *pbMatch = bMatch;
   if( aIter!=aStatic ) sqlite3_free(aIter);
   return rc;
 }
 
 /*
-** All individual term iterators in pPhrase are guaranteed to be valid when
-** this function is called. This function checks if all term iterators
-** point to the same rowid, and if not, advances them until they do.
-** If an EOF is reached before this happens, *pbEof is set to true before
-** returning.
-**
-** SQLITE_OK is returned if an error occurs, or an SQLite error code 
-** otherwise. It is not considered an error code if an iterator reaches
-** EOF.
+** Advance each phrase iterator in phrase pNear. If any reach EOF, set
+** output variable *pbEof to true before returning.
 */
-static int fts5ExprPhraseNextRowidMatch(
+static int fts5ExprNearAdvanceAll(
   Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
-  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
+  Fts5ExprNearset *pNear,         /* Near object to advance iterators of */
   int *pbEof                      /* OUT: Set to true if phrase at EOF */
 ){
-  assert( *pbEof==0 );
-  while( 1 ){
-    int i;
-    int bMatch = 1;
-    i64 iMin = sqlite3Fts5IterRowid(pPhrase->aTerm[0].pIter);
-    for(i=1; i<pPhrase->nTerm; i++){
-      i64 iRowid = sqlite3Fts5IterRowid(pPhrase->aTerm[i].pIter);
-      if( iRowid!=iMin ){
-        bMatch = 0;
-        if( iRowid<iMin ) iMin = iRowid;
-      }
-    }
-    if( bMatch ) break;
-
-    for(i=0; i<pPhrase->nTerm; i++){
-      Fts5IndexIter *pIter = pPhrase->aTerm[i].pIter;
-      while( sqlite3Fts5IterRowid(pIter)>iMin ){
-        sqlite3Fts5IterNext(pIter, 0);
-        if( sqlite3Fts5IterEof(pIter) ){
-          *pbEof = 1;
-          return SQLITE_OK;
-        }
+  int rc = SQLITE_OK;             /* Return code */
+  int i, j;                       /* Phrase and token index, respectively */
+
+  for(i=0; i<pNear->nPhrase; i++){
+    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+    for(j=0; j<pPhrase->nTerm; j++){
+      Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
+      sqlite3Fts5IterNext(pIter, 0);
+      if( sqlite3Fts5IterEof(pIter) ){
+        *pbEof = 1;
+        return rc;
       }
     }
   }
 
-  return SQLITE_OK;
+  return rc;
 }
 
-static int fts5ExprPhraseAdvanceAll(
-  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
-  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
-  int *pbEof                      /* OUT: Set to true if phrase at EOF */
+/*
+** Advance iterator pIter until it points to a value equal to or smaller
+** than the initial value of *piMin. If this means the iterator points
+** to a value smaller than *piMin, update *piMin to the new smallest value.
+**
+** If the iterator reaches EOF, set *pbEof to true before returning. If
+** an error occurs, set *pRc to an error code. If either *pbEof or *pRc
+** are set, return a non-zero value. Otherwise, return zero.
+*/
+static int fts5ExprAdvanceto(
+  Fts5IndexIter *pIter,           /* Iterator to advance */
+  i64 *piMin,                     /* IN/OUT: Minimum rowid seen so far */
+  int *pRc,                       /* OUT: Error code */
+  int *pbEof                      /* OUT: Set to true if EOF */
 ){
-  int i;
-  int rc = SQLITE_OK;
-  for(i=0; i<pPhrase->nTerm; i++){
-    Fts5IndexIter *pIter = pPhrase->aTerm[i].pIter;
+  i64 iMin = *piMin;
+  i64 iRowid;
+  while( (iRowid = sqlite3Fts5IterRowid(pIter))>iMin ){
     sqlite3Fts5IterNext(pIter, 0);
     if( sqlite3Fts5IterEof(pIter) ){
       *pbEof = 1;
-      break;
+      return 1;
     }
   }
+  if( iRowid<iMin ){
+    *piMin = iRowid;
+  }
+
+  return 0;
+}
+
+/*
+** All individual term iterators in pNear are guaranteed to be valid when
+** this function is called. This function checks if all term iterators
+** point to the same rowid, and if not, advances them until they do.
+** If an EOF is reached before this happens, *pbEof is set to true before
+** returning.
+**
+** SQLITE_OK is returned if an error occurs, or an SQLite error code 
+** otherwise. It is not considered an error code if an iterator reaches
+** EOF.
+*/
+static int fts5ExprNearNextRowidMatch(
+  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
+  Fts5ExprNode *pNode
+){
+  Fts5ExprNearset *pNear = pNode->pNear;
+  int rc = SQLITE_OK;
+  int i, j;                       /* Phrase and token index, respectively */
+  i64 iMin;                       /* Smallest rowid any iterator points to */
+  int bMatch;
+
+  iMin = sqlite3Fts5IterRowid(pNear->apPhrase[0]->aTerm[0].pIter);
+  do {
+    bMatch = 1;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      for(j=0; j<pPhrase->nTerm; j++){
+        Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
+        i64 iRowid = sqlite3Fts5IterRowid(pIter);
+        if( iRowid!=iMin ) bMatch = 0;
+        if( fts5ExprAdvanceto(pIter, &iMin, &rc, &pNode->bEof) ) return rc;
+      }
+    }
+  }while( bMatch==0 );
+
+  pNode->iRowid = iMin;
   return rc;
 }
 
 /*
-** Argument pPhrase points to a multi-term phrase object. All individual
-** term iterators point to valid entries (not EOF).
+** Argument pNode points to a NEAR node. All individual term iterators 
+** point to valid entries (not EOF).
 *
 ** This function tests if the term iterators currently all point to the
-** same rowid, and if so, if the rowid matches the phrase constraint. If
-** so, the pPhrase->poslist buffer is populated and the pPhrase->iRowid
+** same rowid, and if so, if the row matches the phrase and NEAR constraints. 
+** If so, the pPhrase->poslist buffers are populated and the pNode->iRowid
 ** variable set before returning. Or, if the current combination of 
 ** iterators is not a match, they are advanced until they are. If one of
 ** the iterators reaches EOF before a match is found, *pbEof is set to
@@ -432,123 +542,106 @@ static int fts5ExprPhraseAdvanceAll(
 ** otherwise. It is not considered an error code if an iterator reaches
 ** EOF.
 */
-static int fts5ExprPhraseNextMatch(
-  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
-  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
-  int *pbEof                      /* OUT: Set to true if phrase at EOF */
+static int fts5ExprNearNextMatch(
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode
 ){
-  int i;                          /* Used to iterate through terms */
-  int rc = SQLITE_OK;             /* Return code */
-  int bMatch = 0;
+  int rc = SQLITE_OK;
+  Fts5ExprNearset *pNear = pNode->pNear;
+  while( 1 ){
+    int i;
 
-  assert( *pbEof==0 );
+    /* Advance the iterators until they are a match */
+    rc = fts5ExprNearNextRowidMatch(pExpr, pNode);
+    if( pNode->bEof || rc!=SQLITE_OK ) break;
 
-  while( 1 ){
-    rc = fts5ExprPhraseNextRowidMatch(pExpr, pPhrase, pbEof);
-    if( rc!=SQLITE_OK || *pbEof ) break;
+    for(i=0; i<pNear->nPhrase; i++){
+      Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
+      if( pPhrase->nTerm>1 ){
+        int bMatch = 0;
+        rc = fts5ExprPhraseIsMatch(pExpr, pPhrase, &bMatch);
+        if( rc!=SQLITE_OK ) return rc;
+        if( bMatch==0 ) break;
+      }else{
+        int n;
+        u8 *a = sqlite3Fts5IterPoslist(pPhrase->aTerm[0].pIter, &n);
+        fts5BufferSet(&rc, &pPhrase->poslist, n, a);
+      }
+    }
 
-    /* At this point, all term iterators are valid and point to the same rowid.
-    ** The following assert() statements verify this.  */
-#ifdef SQLITE_DEBUG
-    for(i=0; i<pPhrase->nTerm; i++){
-      Fts5IndexIter *pIter = pPhrase->aTerm[i].pIter;
-      Fts5IndexIter *pOne = pPhrase->aTerm[0].pIter;
-      assert( 0==sqlite3Fts5IterEof(pIter) );
-      assert( sqlite3Fts5IterRowid(pOne)==sqlite3Fts5IterRowid(pIter) );
+    if( i==pNear->nPhrase ){
+      int bMatch = 1;
+      if( pNear->nPhrase>1 ){
+        rc = fts5ExprNearIsMatch(pNear, &bMatch);
+      }
+      if( rc!=SQLITE_OK || bMatch ) break;
     }
-#endif
 
-    rc = fts5ExprPhraseIsMatch(pExpr, pPhrase, &bMatch);
-    if( rc!=SQLITE_OK || bMatch ) break;
-    rc = fts5ExprPhraseAdvanceAll(pExpr, pPhrase, pbEof);
-    if( rc!=SQLITE_OK || *pbEof ) break;
+    rc = fts5ExprNearAdvanceAll(pExpr, pNear, &pNode->bEof);
+    if( pNode->bEof || rc!=SQLITE_OK ) break;
   }
 
-  pPhrase->iRowid = sqlite3Fts5IterRowid(pPhrase->aTerm[0].pIter);
   return rc;
 }
 
 /*
-** Advance the phrase iterator pPhrase to the next match.
+** Initialize all term iterators in the pNear object. If any term is found
+** to match no documents at all, set *pbEof to true and return immediately,
+** without initializing any further iterators.
 */
-static int fts5ExprPhraseNext(
-  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
-  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
-  int *pbEof                      /* OUT: Set to true if phrase at EOF */
+static int fts5ExprNearInitAll(
+  Fts5Expr *pExpr,
+  Fts5ExprNode *pNode
 ){
-  int i;
-  for(i=0; i<pPhrase->nTerm; i++){
-    Fts5IndexIter *pIter = pPhrase->aTerm[i].pIter;
-    sqlite3Fts5IterNext(pIter, 0);
-    if( sqlite3Fts5IterEof(pIter) ){
-      *pbEof = 1;
-      return SQLITE_OK;
+  Fts5ExprNearset *pNear = pNode->pNear;
+  Fts5ExprTerm *pTerm;
+  Fts5ExprPhrase *pPhrase;
+  int i, j;
+
+  for(i=0; i<pNear->nPhrase; i++){
+    pPhrase = pNear->apPhrase[i];
+    for(j=0; j<pPhrase->nTerm; j++){
+      pTerm = &pPhrase->aTerm[j];
+      pTerm->pIter = sqlite3Fts5IndexQuery(
+          pExpr->pIndex, pTerm->zTerm, strlen(pTerm->zTerm),
+          (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
+          (pExpr->bAsc ? FTS5INDEX_QUERY_ASC : 0)
+      );
+      if( sqlite3Fts5IterEof(pTerm->pIter) ){
+        pNode->bEof = 1;
+        return SQLITE_OK;
+      }
     }
   }
 
-  if( pPhrase->nTerm==1 ){
-    pPhrase->iRowid = sqlite3Fts5IterRowid(pPhrase->aTerm[0].pIter);
-  }else{
-    fts5ExprPhraseNextMatch(pExpr, pPhrase, pbEof);
-  }
-
   return SQLITE_OK;
 }
 
-/*
-** Point phrase object pPhrase at the first matching document. Or, if there 
-** are no matching documents at all, move pPhrase to EOF and set *pbEof to
-** true before returning.
-**
-** If no error occurs, SQLITE_OK is returned. Otherwise, an SQLite error
-** code.
-*/
-static int fts5ExprPhraseFirst(
-  Fts5Expr *pExpr,                /* Expression pPhrase belongs to */
-  Fts5ExprPhrase *pPhrase,        /* Phrase object to initialize */
-  int *pbEof                      /* OUT: Set to true if phrase at EOF */
+static int fts5ExprNearNext(
+  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
+  Fts5ExprNode *pNode
 ){
-  int i;                          /* Used to iterate through terms */
-  int rc = SQLITE_OK;
-
-  for(i=0; i<pPhrase->nTerm; i++){
-    Fts5ExprTerm *pTerm = &pPhrase->aTerm[i];
-    pTerm->pIter = sqlite3Fts5IndexQuery(
-        pExpr->pIndex, pTerm->zTerm, strlen(pTerm->zTerm),
-        (pTerm->bPrefix ? FTS5INDEX_QUERY_PREFIX : 0) |
-        (pExpr->bAsc ? FTS5INDEX_QUERY_ASC : 0)
-    );
-    if( sqlite3Fts5IterEof(pTerm->pIter) ){
-      *pbEof = 1;
-      return SQLITE_OK;
-    }
-  }
-
-  if( pPhrase->nTerm==1 ){
-    const u8 *a; int n;
-    Fts5IndexIter *pIter = pPhrase->aTerm[0].pIter;
-    pPhrase->iRowid = sqlite3Fts5IterRowid(pIter);
-    a = sqlite3Fts5IterPoslist(pIter, &n);
-    if( a ){
-      sqlite3Fts5BufferSet(&rc, &pPhrase->poslist, n, a);
-    }
-  }else{
-    rc = fts5ExprPhraseNextMatch(pExpr, pPhrase, pbEof);
+  int rc = fts5ExprNearAdvanceAll(pExpr, pNode->pNear, &pNode->bEof);
+  if( rc==SQLITE_OK && pNode->bEof==0 ){
+    rc = fts5ExprNearNextMatch(pExpr, pNode);
   }
-
   return rc;
 }
  
 static int fts5ExprNodeFirst(Fts5Expr *pExpr, Fts5ExprNode *pNode){
   int rc = SQLITE_OK;
-
   pNode->bEof = 0;
+
   if( pNode->eType==FTS5_STRING ){
-    Fts5ExprPhrase *pPhrase = pNode->pNear->apPhrase[0];
-    assert( pNode->pNear->nPhrase==1 );
-    assert( pNode->bEof==0 );
-    rc = fts5ExprPhraseFirst(pExpr, pPhrase, &pNode->bEof);
-    pNode->iRowid = pPhrase->iRowid;
+
+    /* Initialize all term iterators in the NEAR object. */
+    rc = fts5ExprNearInitAll(pExpr, pNode);
+
+    /* Attempt to advance to the first match */
+    if( rc==SQLITE_OK && pNode->bEof==0 ){
+      rc = fts5ExprNearNextMatch(pExpr, pNode);
+    }
+
   }else{
     rc = fts5ExprNodeFirst(pExpr, pNode->pLeft);
     if( rc==SQLITE_OK ){
@@ -565,10 +658,7 @@ static int fts5ExprNodeNext(Fts5Expr *pExpr, Fts5ExprNode *pNode){
   int rc = SQLITE_OK;
 
   if( pNode->eType==FTS5_STRING ){
-    Fts5ExprPhrase *pPhrase = pNode->pNear->apPhrase[0];
-    assert( pNode->pNear->nPhrase==1 );
-    rc = fts5ExprPhraseNext(pExpr, pPhrase, &pNode->bEof);
-    pNode->iRowid = pPhrase->iRowid;
+    rc = fts5ExprNearNext(pExpr, pNode);
   }else{
     assert( 0 );
   }
@@ -806,6 +896,11 @@ Fts5ExprPhrase *sqlite3Fts5ParseTerm(
   return sCtx.pPhrase;
 }
 
+/*
+** Token pTok has appeared in a MATCH expression where the NEAR operator
+** is expected. If token pTok does not contain "NEAR", store an error
+** in the pParse object.
+*/
 void sqlite3Fts5ParseNear(Fts5Parse *pParse, Fts5Token *pTok){
   if( pParse->rc==SQLITE_OK ){
     if( pTok->n!=4 || memcmp("NEAR", pTok->p, 4) ){
diff --git a/ext/fts5/fts5_index.c b/ext/fts5/fts5_index.c
index e60ec5f503..af69b4280d 100644
--- a/ext/fts5/fts5_index.c
+++ b/ext/fts5/fts5_index.c
@@ -1156,7 +1156,7 @@ static void fts5SegIterNext(
     int n = pLeaf->n;
 
     iOff = pIter->iLeafOffset;
-    if( iOff<=n ){
+    if( iOff<n ){
       int nPoslist;
       iOff += getVarint32(&a[iOff], nPoslist);
       iOff += nPoslist;
diff --git a/manifest b/manifest
index 2c8ddafbb9..f8d149a28e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\ssupport\sfor\sphrase\squeries\sto\sfts5.
-D 2014-07-02T20:18:49.027
+C Add\ssupport\sfor\sNEAR\sexpressions\sto\sfts5.
+D 2014-07-03T20:39:39.548
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in b03432313a3aad96c706f8164fb9f5307eaf19f5
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -107,8 +107,8 @@ F ext/fts5/fts5.c 1af3184dd9c0e5c1686f71202d6b6cac8f225f05
 F ext/fts5/fts5Int.h b7a684ff3508ab24437886f8bc873a16f494a7db
 F ext/fts5/fts5_buffer.c f1a26a79e2943fe4388e531fa141941b5eb6d31a
 F ext/fts5/fts5_config.c 94f1b4cb4de6a7cd5780c14adb0198e289df8cef
-F ext/fts5/fts5_expr.c aacfcf6b7c14ca5987ba1de0bd080eee31fca98c
-F ext/fts5/fts5_index.c 6bb95f6a1ed0e50bc9f2dce7b7a92859f5821364
+F ext/fts5/fts5_expr.c 84dd8c1f313f795b41f3fc5f73bee013e8301b68
+F ext/fts5/fts5_index.c d8ab9712e38dc1beb9a9145ec89e18dc083c0467
 F ext/fts5/fts5_storage.c 7848d8f8528d798bba159900ea310a6d4a279da8
 F ext/icu/README.txt d9fbbad0c2f647c3fdf715fc9fd64af53aedfc43
 F ext/icu/icu.c d415ccf984defeb9df2c0e1afcfaa2f6dc05eacb
@@ -593,7 +593,8 @@ F test/fts4merge4.test d895b1057a7798b67e03455d0fa50e9ea836c47b
 F test/fts4noti.test 524807f0c36d49deea7920cdd4cd687408b58849
 F test/fts4unicode.test 01ec3fe2a7c3cfff3b4c0581b83caa11b33efa36
 F test/fts5aa.test c8d3b9694f6b2864161c7437408464a535d19343
-F test/fts5ab.test bdc1dd9d58163c0c7b184be817f82e3bf8a81c37
+F test/fts5ab.test 4db86a9473ee2a8c2cb30e0d81df21c6022f99b6
+F test/fts5ac.test cc4fc45a85fde7fbe8da135aed6b25d2795ba9f6
 F test/fts5ea.test ff43b40f8879ba50b82def70f2ab67c195d1a1d4
 F test/full.test 6b3c8fb43c6beab6b95438c1675374b95fab245d
 F test/func.test ae97561957aba6ca9e3a7b8a13aac41830d701ef
@@ -1189,7 +1190,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 62f2ff20418702ed0fbf708369edf5638445b51b
-R 773d748328905c117f50682aca9f537a
+P 2e5652e6526b8fb3f5c163168d95bc0bb4c93686
+R f894350f59d9ccf43dee7a3b5d2aafff
 U dan
-Z 194302280b1431e713a39a0adc2c19fe
+Z be26a54244aa4231a7a300eba9899e25
diff --git a/manifest.uuid b/manifest.uuid
index 9cec4319b1..a90859e837 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2e5652e6526b8fb3f5c163168d95bc0bb4c93686
\ No newline at end of file
+250ae8d40115e2e47cc5a1e8a427fa8c0a89124d
\ No newline at end of file
diff --git a/test/fts5ab.test b/test/fts5ab.test
index 1cbab9d616..88a876d3b2 100644
--- a/test/fts5ab.test
+++ b/test/fts5ab.test
@@ -97,7 +97,7 @@ foreach {tn expr res} {
 #-------------------------------------------------------------------------
 #
 reset_db
-do_execsql_test 2.0 {
+do_execsql_test 3.0 {
   CREATE VIRTUAL TABLE t1 USING fts5(a,b);
   INSERT INTO t1(t1) VALUES('pgsz=32');
 }
@@ -114,8 +114,8 @@ foreach {tn a b} {
    9 {abash abase abate abashing abashed} {abandon abandoned}
    10 {abate abandoning abandons abasement aback} {abandon abandoning}
 } {
-  do_execsql_test 2.1.$tn.1 { INSERT INTO t1 VALUES($a, $b) } 
-  do_execsql_test 2.1.$tn.2 { INSERT INTO t1(t1) VALUES('integrity-check') }
+  do_execsql_test 3.1.$tn.1 { INSERT INTO t1 VALUES($a, $b) } 
+  do_execsql_test 3.1.$tn.2 { INSERT INTO t1(t1) VALUES('integrity-check') }
 }
 
 foreach {tn expr res} {
@@ -124,12 +124,19 @@ foreach {tn expr res} {
   3 {abase + abash} {1}
   4 {abash + abase} {9}
   5 {abaft + abashing} {8 5}
+
   6 {abandon + abandoning} {10}
   7 {"abashing abases abasement abaft abashing"} {8}
 } {
-  do_execsql_test 2.2.$tn {
+  do_execsql_test 3.2.$tn {
     SELECT rowid FROM t1 WHERE t1 MATCH $expr
   } $res
 }
 
+breakpoint
+do_execsql_test 3.3 {
+  SELECT rowid FROM t1 WHERE t1 MATCH 'NEAR(aback abate, 2)'
+} {6}
+
+
 finish_test
diff --git a/test/fts5ac.test b/test/fts5ac.test
new file mode 100644
index 0000000000..d5556ef706
--- /dev/null
+++ b/test/fts5ac.test
@@ -0,0 +1,168 @@
+# 2014 June 17
+#
+# 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 regression tests for SQLite library.  The
+# focus of this script is testing the FTS5 module.
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix fts5ac
+
+# If SQLITE_ENABLE_FTS3 is defined, omit this file.
+ifcapable !fts3 {
+  finish_test
+  return
+}
+
+do_execsql_test 1.0 {
+  CREATE VIRTUAL TABLE xx USING fts5(x,y);
+  INSERT INTO xx(xx) VALUES('pgsz=32');
+}
+
+set data {
+    0   {p o q e z k z p n f y u z y n y}   {l o o l v v k}
+    1   {p k h h p y l l h i p v n}         {p p l u r i f a j g e r r x w}
+    2   {l s z j k i m p s}                 {l w e j t j e e i t w r o p o}
+    3   {x g y m y m h p}                   {k j j b r e y y a k y}
+    4   {q m a i y i z}                     {o w a g k x g j m w e u k}
+    5   {k o a w y b s z}                   {s g l m m l m g p}
+    6   {d a q i z h b l c p k j g k}       {p x u j x t v c z}
+    7   {f d a g o c t i}                   {w f c x l d r k i j}
+    8   {y g w u b q p o m j y b p a e k}   {r i d k y w o z q m a t p}
+    9   {r k o m c c j s x m x m x m q r}   {y r c a q d z k n x n}
+    10  {k j q m g q a j d}                 {d d e z g w h c d o o g x d}
+    11  {j z u m o y q j f w e e w t r j w} {g m o r x n t n w i f g l z f}
+    12  {s y w a w d o h x m k}             {c w k z b p o r a}
+    13  {u t h x e g s k n g i}             {f j w g c s r}
+    14  {b f i c s u z t k}                 {c k q s j u i z o}
+    15  {n a f n u s w h y n s i q e w}     {x g e g a s s h n}
+    16  {k s q e j n p}                     {t r j f t o e k k l m i}
+    17  {g d t u w r o p m n m n p h b o u} {h s w o s l j e}
+    18  {f l q y q q g e e x j r}           {n b r r g e i r t x q k}
+    19  {f i r g o a w e p i l o a w}       {e k r z t d g h g i b d i e m}
+    20  {l d u u f p y}                     {g o m m u x m g l j t t x x u}
+    21  {m c d k x i c z l}                 {m i a i e u h}
+    22  {w b f o c g x y j}                 {z d w x d f h i p}
+    23  {w u i u x t c h k i b}             {b y k h b v r t g j}
+    24  {h f d j s w s b a p k}             {a q y u z e y m m j q r}
+    25  {d i x y x x k i y f s d j h z p n} {l l q m e t c w g y h t s v g}
+    26  {g s q w t d k x g f m j p k y}     {r m b x e l t d}
+    27  {j l s q u g y v e c l o}           {m f l m m m h g x x l n c}
+    28  {c t j g v r s b z j}               {l c f y d t q n}
+    29  {e x z y w i h l}                   {b n b x e y q e n u m}
+    30  {g y y h j b w r}                   {q b q f u s k c k g r}
+    31  {g u l x l b r c m z b u c}         {k g t b x k x n t e z d h o}
+    32  {w g v l z f b z h p s c v h}       {g e w v m h k r g w a r f q}
+    33  {c g n f u d o y o b}               {e y o h x x y y i z s b h a j}
+    34  {v y h c q u u s q y x x k s q}     {d n r m y k n t i r n w e}
+    35  {o u c x l e b t a}                 {y b a x y f z x r}
+    36  {x p h l j a a u u j h}             {x o f s z m b c q p}
+    37  {k q t i c a q n m v v}             {v r z e f m y o}
+    38  {r w t t t t r v v o e p g h}       {l w x a g a u h y}
+    39  {o p v g v b a g o}                 {j t q c r b b g y z}
+    40  {f s o r o d t h q f x l}           {r d b m k i f s t d l m y x j w}
+    41  {t m o t m f m f}                   {i p i q j v n v m b q}
+    42  {t x w a r l w d t b c o d o}       {a h f h w z d n s}
+    43  {t u q c d g p q x j o l c x c}     {m n t o z z j a y}
+    44  {v d i i k b f s z r v r z y}       {g n q y s x x m b x c l w}
+    45  {p v v a c s z y e o l}             {m v t u d k m k q b d c v z r}
+    46  {f y k l d r q w r s t r e}         {h m v r r l r r t f q e x y}
+    47  {w l n l t y x}                     {n h s l a f c h u f l x x m v n o}
+    48  {t n v i k e b p z p d j j l i o}   {i v z p g u e j s i k n h w d c}
+    49  {z v x p n l t a j c}               {e j l e n c e t a d}
+    50  {w u b x u i v h a i y m m r p m s} {s r h d o g z y f f x e}
+    51  {d c c x b c a x g}                 {p r a j v u y}
+    52  {f w g r c o d l t u e z h i}       {j l l s s b j m}
+    53  {p m t f k i x}                     {u v y a z g w v v m x h i}
+    54  {l c z g l o j i c d e b}           {b f v y w u i b e i y}
+    55  {r h c x f x a d s}                 {z x y k f l r b q c v}
+    56  {v x x c y h z x b g m o q n c}     {h n b i t g h a q b c o r u}
+    57  {d g l o h t b s b r}               {n u e p t i m u}
+    58  {t d y e t d c w u o s w x f c h}   {i o s v y b r d r}
+    59  {l b a p q n d r}                   {k d c c d n y q h g a o p e x}
+    60  {f r z v m p k r}                   {x x r i s b a g f c}
+    61  {s a z i e r f i w c n y v z t k s} {y y i r y n l s b w i e k n}
+    62  {n x p r e x q r m v i b y}         {f o o z n b s r q j}
+    63  {y j s u j x o n r q t f}           {f v k n v x u s o a d e f e}
+    64  {u s i l y c x q}                   {r k c h p c h b o s s u s p b}
+    65  {m p i o s h o}                     {s w h u n d m n q t y k b w c}
+    66  {l d f g m x x x o}                 {s w d d f b y j j h h t i y p j o}
+    67  {c b m h f n v w n h}               {i r w i e x r w l z p x u g u l s}
+    68  {y a h u h i m a y q}               {d d r x h e v q n z y c j}
+    69  {c x f d x o n p o b r t b l p l}   {m i t k b x v f p t m l l y r o}
+    70  {u t l w w m s}                     {m f m o l t k o p e}
+    71  {f g q e l n d m z x q}             {z s i i i m f w w f n g p e q}
+    72  {n l h a v u o d f j d e x}         {v v s l f g d g r a j x i f z x}
+    73  {x v m v f i g q e w}               {r y s j i k m j j e d g r n o i f}
+    74  {g d y n o h p s y q z j d w n h w} {x o d l t j i b r d o r y}
+    75  {p g b i u r b e q d v o a g w m k} {q y z s f q o h}
+    76  {u z a q u f i f f b}               {b s p b a a d x r r i q f}
+    77  {w h h z t h p o a h h e e}         {h w r p h k z v y f r x}
+    78  {c a r k i a p u x}                 {f w l p t e m l}
+    79  {q q u k o t r k z}                 {f b m c w p s s o z}
+    80  {t i g v y q s r x m r x z e f}     {x o j w a u e y s j c b u p p r o}
+    81  {n j n h r l a r e o z w e}         {v o r r j a v b}
+    82  {i f i d k w d n h}                 {o i d z i z l m w s b q v u}
+    83  {m d g q q b k b w f q q p p}       {j m q f b y c i z k y q p l e a}
+    84  {m x o n y f g}                     {y c n x n q j i y c l h b r q z}
+    85  {v o z l n p c}                     {g n j n t b b x n c l d a g j v}
+    86  {z n a y f b t k k t d b z a v}     {r p c n r u k u}
+    87  {b q t x z e c w}                   {q a o a l o a h i m j r}
+    88  {j f h o x x a z g b a f a m i b}   {j z c z y x e x w t}
+    89  {t c t p r s u c q n}               {z x l i k n f q l n t}
+    90  {w t d q j g m r f k n}             {l e w f w w a l y q k i q t p c t}
+    91  {c b o k l i c b s j n m b l}       {y f p q o w g}
+    92  {f y d j o q t c c q m f j s t}     {f h e d y m o k}
+    93  {k x j r m a d o i z j}             {r t t t f e b r x i v j v g o}
+    94  {s f e a e t i h h d q p z t q}     {b k m k w h c}
+    95  {h b n j t k i h o q u}             {w n g i t o k c a m y p f l x c p}
+    96  {f c x p y r b m o l m o a}         {p c a q s u n n x d c f a o}
+    97  {u h h k m n k}                     {u b v n u a o c}
+    98  {s p e t c z d f n w f}             {l s f j b l c e s h}
+    99  {r c v w i v h a t a c v c r e}     {h h u m g o f b a e o}
+}
+
+do_test 1.1 {
+  foreach {id x y} $data {
+    execsql { INSERT INTO xx(rowid, x, y) VALUES($id, $x, $y) }
+  }
+} {}
+
+foreach {tn phrase} {
+  1 "o"
+  2 "b q"
+  3 "e a e"
+  4 "m d g q q b k b w f q q p p"
+  5 "l o o l v v k"
+  6 "a"
+  7 "b"
+  8 "c"
+  9 "no"
+  10 "L O O L V V K"
+} {
+  set res [list]
+  foreach {id x y} $data {
+    set pat [string tolower $phrase]
+    if {[string first $pat $x]>=0 || [string first $pat $y]>=0} {
+      set res [concat $id $res]
+    }
+  }
+  set n [llength $res]
+  do_execsql_test 1.2.$tn.$n { 
+    SELECT rowid FROM xx WHERE xx match '"' || $phrase || '"'
+  } $res
+}
+
+
+
+finish_test
+