Get LIMIT and OFFSET working again for negative limits and offsets.

Ticket #1586. (CVS 2889)

FossilOrigin-Name: b2ac0be07ec76ab23b7e5b800c0bc62d0bc97f4b

5 files changed, 72 insertions, 44 deletions

diff --git a/src/analyze.c b/src/analyze.c
index 4669c733b..acd812b27 100644
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code associated with the ANALYZE command.
 **
-** @(#) $Id: analyze.c,v 1.13 2006/01/07 13:21:04 danielk1977 Exp $
+** @(#) $Id: analyze.c,v 1.14 2006/01/08 18:10:18 drh Exp $
 */
 #ifndef SQLITE_OMIT_ANALYZE
 #include "sqliteInt.h"
@@ -152,7 +152,7 @@ static void analyzeOneTable(
     endOfLoop = sqlite3VdbeMakeLabel(v);
     sqlite3VdbeAddOp(v, OP_Rewind, iIdxCur, endOfLoop);
     topOfLoop = sqlite3VdbeCurrentAddr(v);
-    sqlite3VdbeAddOp(v, OP_MemIncr, iMem, 0);
+    sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem);
     for(i=0; i<nCol; i++){
       sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i);
       sqlite3VdbeAddOp(v, OP_MemLoad, iMem+nCol+i+1, 0);
@@ -160,7 +160,7 @@ static void analyzeOneTable(
     }
     sqlite3VdbeAddOp(v, OP_Goto, 0, endOfLoop);
     for(i=0; i<nCol; i++){
-      addr = sqlite3VdbeAddOp(v, OP_MemIncr, iMem+i+1, 0);
+      addr = sqlite3VdbeAddOp(v, OP_MemIncr, 1, iMem+i+1);
       sqlite3VdbeChangeP2(v, topOfLoop + 3*i + 3, addr);
       sqlite3VdbeAddOp(v, OP_Column, iIdxCur, i);
       sqlite3VdbeAddOp(v, OP_MemStore, iMem+nCol+i+1, 1);
diff --git a/src/insert.c b/src/insert.c
index dea6c6fc1..3de2c4250 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle INSERT statements in SQLite.
 **
-** $Id: insert.c,v 1.153 2006/01/07 13:21:04 danielk1977 Exp $
+** $Id: insert.c,v 1.154 2006/01/08 18:10:18 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -636,7 +636,7 @@ void sqlite3Insert(
   /* Update the count of rows that are inserted
   */
   if( (db->flags & SQLITE_CountRows)!=0 ){
-    sqlite3VdbeAddOp(v, OP_MemIncr, iCntMem, 0);
+    sqlite3VdbeAddOp(v, OP_MemIncr, 1, iCntMem);
   }
 
   if( triggers_exist ){
diff --git a/src/pragma.c b/src/pragma.c
index a869657ae..ac08d2ff1 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
 **
-** $Id: pragma.c,v 1.109 2006/01/06 14:32:20 drh Exp $
+** $Id: pragma.c,v 1.110 2006/01/08 18:10:18 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -686,7 +686,7 @@ void sqlite3Pragma(
       sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
       sqlite3VdbeAddOp(v, OP_Concat, 0, 1);
       sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
-      sqlite3VdbeAddOp(v, OP_MemIncr, 0, 0);
+      sqlite3VdbeAddOp(v, OP_MemIncr, 1, 0);
 
       /* Make sure all the indices are constructed correctly.
       */
@@ -700,11 +700,11 @@ void sqlite3Pragma(
         sqlite3OpenTableAndIndices(pParse, pTab, 1, OP_OpenRead);
         sqlite3VdbeAddOp(v, OP_MemInt, 0, 1);
         loopTop = sqlite3VdbeAddOp(v, OP_Rewind, 1, 0);
-        sqlite3VdbeAddOp(v, OP_MemIncr, 1, 0);
+        sqlite3VdbeAddOp(v, OP_MemIncr, 1, 1);
         for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
           int jmp2;
           static const VdbeOpList idxErr[] = {
-            { OP_MemIncr,     0,  0,  0},
+            { OP_MemIncr,     1,  0,  0},
             { OP_String8,     0,  0,  "rowid "},
             { OP_Rowid,       1,  0,  0},
             { OP_String8,     0,  0,  " missing from index "},
@@ -724,12 +724,12 @@ void sqlite3Pragma(
           static const VdbeOpList cntIdx[] = {
              { OP_MemInt,       0,  2,  0},
              { OP_Rewind,       0,  0,  0},  /* 1 */
-             { OP_MemIncr,      2,  0,  0},
+             { OP_MemIncr,      1,  2,  0},
              { OP_Next,         0,  0,  0},  /* 3 */
              { OP_MemLoad,      1,  0,  0},
              { OP_MemLoad,      2,  0,  0},
              { OP_Eq,           0,  0,  0},  /* 6 */
-             { OP_MemIncr,      0,  0,  0},
+             { OP_MemIncr,      1,  0,  0},
              { OP_String8,      0,  0,  "wrong # of entries in index "},
              { OP_String8,      0,  0,  0},  /* 9 */
              { OP_Concat,       0,  0,  0},
diff --git a/src/select.c b/src/select.c
index b482de90d..9b0be55ec 100644
--- a/src/select.c
+++ b/src/select.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
 **
-** $Id: select.c,v 1.287 2006/01/08 05:02:55 drh Exp $
+** $Id: select.c,v 1.288 2006/01/08 18:10:18 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -363,14 +363,14 @@ static void pushOntoSorter(
   sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
   sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
   if( pSelect->iLimit>=0 ){
-    int addr1;
-    sqlite3VdbeAddOp(v, OP_MemIncr, pSelect->iLimit+1, 0);
-    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, pSelect->iLimit+1, 0);
-    sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
+    int addr1, addr2;
+    addr1 = sqlite3VdbeAddOp(v, OP_IfMemZero, pSelect->iLimit+1, 0);
+    sqlite3VdbeAddOp(v, OP_MemIncr, -1, pSelect->iLimit+1);
+    addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
     sqlite3VdbeJumpHere(v, addr1);
     sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
     sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
-    sqlite3VdbeJumpHere(v, addr1+1);
+    sqlite3VdbeJumpHere(v, addr2);
     pSelect->iLimit = -1;
   }
 }
@@ -385,15 +385,15 @@ static void codeOffset(
   int nPop          /* Number of times to pop stack when jumping */
 ){
   if( p->iOffset>=0 && iContinue!=0 ){
-    int addr = sqlite3VdbeCurrentAddr(v) + 3;
-    if( nPop>0 ) addr++;
-    sqlite3VdbeAddOp(v, OP_MemIncr, p->iOffset, 0);
-    sqlite3VdbeAddOp(v, OP_IfMemPos, p->iOffset, addr);
+    int addr;
+    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
+    addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, addr);
     if( nPop>0 ){
       sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
     }
     sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
     VdbeComment((v, "# skip OFFSET records"));
+    sqlite3VdbeJumpHere(v, addr);
   }
 }
 
@@ -617,7 +617,7 @@ static int selectInnerLoop(
   /* Jump to the end of the loop if the LIMIT is reached.
   */
   if( p->iLimit>=0 && pOrderBy==0 ){
-    sqlite3VdbeAddOp(v, OP_MemIncr, p->iLimit, 0);
+    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
     sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, iBreak);
   }
   return 0;
@@ -739,7 +739,7 @@ static void generateSortTail(
   /* Jump to the end of the loop when the LIMIT is reached
   */
   if( p->iLimit>=0 ){
-    sqlite3VdbeAddOp(v, OP_MemIncr, p->iLimit, 0);
+    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
     sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, brk);
   }
 
@@ -1365,6 +1365,7 @@ Vdbe *sqlite3GetVdbe(Parse *pParse){
   return v;
 }
 
+
 /*
 ** Compute the iLimit and iOffset fields of the SELECT based on the
 ** pLimit and pOffset expressions.  pLimit and pOffset hold the expressions
@@ -1384,6 +1385,11 @@ Vdbe *sqlite3GetVdbe(Parse *pParse){
 ** SELECT statements.
 */
 static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
+  Vdbe *v;
+  int iLimit;
+  int iOffset;
+  int addr1, addr2;
+
   /* 
   ** "LIMIT -1" always shows all rows.  There is some
   ** contraversy about what the correct behavior should be.
@@ -1391,36 +1397,41 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   ** no rows.
   */
   if( p->pLimit ){
-    int iMem = pParse->nMem;
+    p->iLimit = iLimit = pParse->nMem;
     pParse->nMem += 2;
-    Vdbe *v = sqlite3GetVdbe(pParse);
+    v = sqlite3GetVdbe(pParse);
     if( v==0 ) return;
     sqlite3ExprCode(pParse, p->pLimit);
     sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
-    sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
-    sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
+    sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 0);
     VdbeComment((v, "# LIMIT counter"));
-    sqlite3VdbeAddOp(v, OP_IfMemZero, iMem, iBreak);
-    p->iLimit = iMem;
+    sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
   }
   if( p->pOffset ){
-    int iMem = pParse->nMem++;
-    Vdbe *v = sqlite3GetVdbe(pParse);
+    p->iOffset = iOffset = pParse->nMem++;
+    v = sqlite3GetVdbe(pParse);
     if( v==0 ) return;
     sqlite3ExprCode(pParse, p->pOffset);
     sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
-    sqlite3VdbeAddOp(v, OP_Negative, 0, 0);
-    sqlite3VdbeAddOp(v, OP_MemStore, iMem, p->pLimit==0);
+    sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
     VdbeComment((v, "# OFFSET counter"));
+    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
+    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+    sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
+    sqlite3VdbeJumpHere(v, addr1);
     if( p->pLimit ){
       sqlite3VdbeAddOp(v, OP_Add, 0, 0);
     }
-    p->iOffset = iMem;
   }
   if( p->pLimit ){
-    Vdbe *v = pParse->pVdbe;
-    sqlite3VdbeAddOp(v, OP_MemStore, p->iLimit+1, 1);
+    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
+    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+    sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
+    addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
+    sqlite3VdbeJumpHere(v, addr1);
+    sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
     VdbeComment((v, "# LIMIT+OFFSET"));
+    sqlite3VdbeJumpHere(v, addr2);
   }
 }
 
diff --git a/src/vdbe.c b/src/vdbe.c
index 22e939353..53cf82f77 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.517 2006/01/08 05:26:41 drh Exp $
+** $Id: vdbe.c,v 1.518 2006/01/08 18:10:18 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -4277,28 +4277,26 @@ case OP_MemMax: {        /* no-push */
 }
 #endif /* SQLITE_OMIT_AUTOINCREMENT */
 
-/* Opcode: MemIncr P1 * *
+/* Opcode: MemIncr P1 P2 *
 **
-** Increment the integer valued memory cell P1 by 1.
+** Increment the integer valued memory cell P2 by the value in P1.
 **
 ** It is illegal to use this instruction on a memory cell that does
 ** not contain an integer.  An assertion fault will result if you try.
 */
 case OP_MemIncr: {        /* no-push */
-  int i = pOp->p1;
+  int i = pOp->p2;
   Mem *pMem;
   assert( i>=0 && i<p->nMem );
   pMem = &p->aMem[i];
   assert( pMem->flags==MEM_Int );
-  pMem->i++;
-  assert( pOp->p2==0 );
+  pMem->i += pOp->p1;
   break;
 }
 
 /* Opcode: IfMemPos P1 P2 *
 **
-** If the value of memory cell P1 is 1 or greater, jump to P2.  If
-** the memory cell holds an integer of 0 or less.
+** If the value of memory cell P1 is 1 or greater, jump to P2.
 **
 ** It is illegal to use this instruction on a memory cell that does
 ** not contain an integer.  An assertion fault will result if you try.
@@ -4315,6 +4313,25 @@ case OP_IfMemPos: {        /* no-push */
   break;
 }
 
+/* Opcode: IfMemNeg P1 P2 *
+**
+** If the value of memory cell P1 is less than zero, jump to P2. 
+**
+** It is illegal to use this instruction on a memory cell that does
+** not contain an integer.  An assertion fault will result if you try.
+*/
+case OP_IfMemNeg: {        /* no-push */
+  int i = pOp->p1;
+  Mem *pMem;
+  assert( i>=0 && i<p->nMem );
+  pMem = &p->aMem[i];
+  assert( pMem->flags==MEM_Int );
+  if( pMem->i<0 ){
+     pc = pOp->p2 - 1;
+  }
+  break;
+}
+
 /* Opcode: IfMemZero P1 P2 *
 **
 ** If the value of memory cell P1 is exactly 0, jump to P2.