Add serial-types 8 and 9 for integer constants of 0 and 1 that use zero

bytes of storage.  Make the default file format 4.  Add the
SQLITE_DEFAULT_FILE_FORMAT compile-time option to lower the default
file format number so that newly created databases can be read and
written by older versions of SQLite. (CVS 2845)

FossilOrigin-Name: ae301db8a61a74bc72f67f5766811d89a3b3ec72

6 files changed, 71 insertions, 48 deletions

diff --git a/src/build.c b/src/build.c
index 39de2fdc9..b0e81003d 100644
--- a/src/build.c
+++ b/src/build.c
@@ -22,7 +22,7 @@
 **     COMMIT
 **     ROLLBACK
 **
-** $Id: build.c,v 1.362 2005/12/29 01:11:37 drh Exp $
+** $Id: build.c,v 1.363 2005/12/29 19:23:07 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -764,7 +764,7 @@ void sqlite3StartTable(
     sqlite3VdbeAddOp(v, OP_ReadCookie, iDb, 1);   /* file_format */
     lbl = sqlite3VdbeMakeLabel(v);
     sqlite3VdbeAddOp(v, OP_If, 0, lbl);
-    sqlite3VdbeAddOp(v, OP_Integer, 1, 0);   /* file format defaults to 1 */
+    sqlite3VdbeAddOp(v, OP_Integer, SQLITE_DEFAULT_FILE_FORMAT, 0);
     sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 1);
     sqlite3VdbeAddOp(v, OP_Integer, db->enc, 0);
     sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 4);
@@ -2112,7 +2112,6 @@ void sqlite3CreateIndex(
   Token nullId;        /* Fake token for an empty ID list */
   DbFixer sFix;        /* For assigning database names to pTable */
   int sortOrderMask;   /* 1 to honor DESC in index.  0 to ignore. */
-  int descSeen = 0;    /* Changes to true if a DESC is seen */
   sqlite3 *db = pParse->db;
   Db *pDb;             /* The specific table containing the indexed database */
   int iDb;             /* Index of the database that is being written */
@@ -2264,7 +2263,7 @@ void sqlite3CreateIndex(
 
   /* Check to see if we should honor DESC requests on index columns
   */
-  if( pDb->file_format>=4 || (!pDb->descIndex && !db->init.busy) ){
+  if( pDb->file_format>=4 ){
     sortOrderMask = -1;   /* Honor DESC */
   }else{
     sortOrderMask = 0;    /* Ignore DESC */
@@ -2299,11 +2298,8 @@ void sqlite3CreateIndex(
     ){
       goto exit_create_index;
     }
-    requestedSortOrder = pListItem->sortOrder;
-    pDb->descIndex |= requestedSortOrder;
-    requestedSortOrder &= sortOrderMask;
+    requestedSortOrder = pListItem->sortOrder & sortOrderMask;
     pIndex->keyInfo.aSortOrder[i] = requestedSortOrder;
-    descSeen |= requestedSortOrder;
   }
   pIndex->keyInfo.nField = pList->nExpr;
   sqlite3DefaultRowEst(pIndex);
@@ -2404,11 +2400,6 @@ void sqlite3CreateIndex(
     sqlite3VdbeAddOp(v, OP_CreateIndex, iDb, 0);
     sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
 
-    /* Make sure the file_format is at least 4 if we have DESC indices. */
-    if( descSeen ){
-      sqlite3MinimumFileFormat(pParse, iDb, 4);
-    }
-
     /* Gather the complete text of the CREATE INDEX statement into
     ** the zStmt variable
     */
diff --git a/src/prepare.c b/src/prepare.c
index f530dd874..164c4149e 100644
--- a/src/prepare.c
+++ b/src/prepare.c
@@ -13,7 +13,7 @@
 ** interface, and routines that contribute to loading the database schema
 ** from disk.
 **
-** $Id: prepare.c,v 1.10 2005/12/16 01:06:17 drh Exp $
+** $Id: prepare.c,v 1.11 2005/12/29 19:23:07 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -258,13 +258,13 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   ** file_format==1    Version 3.0.0.
   ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
   ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
-  ** file_format==4    Version 3.3.0.  // DESC indices
+  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
   */
   pDb->file_format = meta[1];
   if( pDb->file_format==0 ){
     pDb->file_format = 1;
   }
-  if( pDb->file_format>4 ){
+  if( pDb->file_format>SQLITE_MAX_FILE_FORMAT ){
     sqlite3BtreeCloseCursor(curMain);
     sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
     return SQLITE_ERROR;
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index b5ff1c207..2737c1d16 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.443 2005/12/29 01:11:37 drh Exp $
+** @(#) $Id: sqliteInt.h,v 1.444 2005/12/29 19:23:07 drh Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
@@ -141,6 +141,17 @@
 #define SQLITE_MAX_VARIABLE_NUMBER 999
 
 /*
+** The "file format" number is an integer that is incremented whenever
+** the VDBE-level file format changes.  The following macros define the
+** the default file format for new databases and the maximum file format
+** that the library can read.
+*/
+#define SQLITE_MAX_FILE_FORMAT 4
+#ifndef SQLITE_DEFAULT_FILE_FORMAT
+# define SQLITE_DEFAULT_FILE_FORMAT 4
+#endif
+
+/*
 ** Provide a default value for TEMP_STORE in case it is not specified
 ** on the command-line
 */
@@ -360,7 +371,6 @@ struct Db {
   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
   u8 safety_level;     /* How aggressive at synching data to disk */
   u8 file_format;      /* Schema format version for this file */
-  u8 descIndex;        /* True if any index uses the DESC attribute */
   int cache_size;      /* Number of pages to use in the cache */
   Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
   void *pAux;               /* Auxiliary data.  Usually NULL */
diff --git a/src/vdbe.c b/src/vdbe.c
index ed8f392b8..0c1a9f7c4 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 1.508 2005/12/21 18:36:46 drh Exp $
+** $Id: vdbe.c,v 1.509 2005/12/29 19:23:07 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -2107,7 +2107,7 @@ op_column_out:
 **
 ** See also OP_MakeIdxRec
 */
-/* Opcode: MakeRecordI P1 P2 P3
+/* Opcode: MakeIdxRec P1 P2 P3
 **
 ** This opcode works just OP_MakeRecord except that it reads an extra
 ** integer from the stack (thus reading a total of abs(P1+1) entries)
@@ -2149,6 +2149,7 @@ case OP_MakeRecord: {
   int jumpIfNull;        /* Jump here if non-zero and any entries are NULL. */
   int addRowid;          /* True to append a rowid column at the end */
   char *zAffinity;       /* The affinity string for the record */
+  int file_format;       /* File format to use for encoding */
 
   leaveOnStack = ((pOp->p1<0)?1:0);
   nField = pOp->p1 * (leaveOnStack?-1:1);
@@ -2159,6 +2160,7 @@ case OP_MakeRecord: {
   pData0 = &pTos[1-nField];
   assert( pData0>=p->aStack );
   containsNull = 0;
+  file_format = p->minWriteFileFormat;
 
   /* Loop through the elements that will make up the record to figure
   ** out how much space is required for the new record.
@@ -2170,7 +2172,7 @@ case OP_MakeRecord: {
     if( pRec->flags&MEM_Null ){
       containsNull = 1;
     }
-    serial_type = sqlite3VdbeSerialType(pRec);
+    serial_type = sqlite3VdbeSerialType(pRec, file_format);
     nData += sqlite3VdbeSerialTypeLen(serial_type);
     nHdr += sqlite3VarintLen(serial_type);
   }
@@ -2183,7 +2185,7 @@ case OP_MakeRecord: {
     pRowid = &pTos[0-nField];
     assert( pRowid>=p->aStack );
     sqlite3VdbeMemIntegerify(pRowid);
-    serial_type = sqlite3VdbeSerialType(pRowid);
+    serial_type = sqlite3VdbeSerialType(pRowid, 0);
     nData += sqlite3VdbeSerialTypeLen(serial_type);
     nHdr += sqlite3VarintLen(serial_type);
   }
@@ -2209,17 +2211,17 @@ case OP_MakeRecord: {
   zCsr = zNewRecord;
   zCsr += sqlite3PutVarint(zCsr, nHdr);
   for(pRec=pData0; pRec<=pTos; pRec++){
-    serial_type = sqlite3VdbeSerialType(pRec);
+    serial_type = sqlite3VdbeSerialType(pRec, file_format);
     zCsr += sqlite3PutVarint(zCsr, serial_type);      /* serial type */
   }
   if( addRowid ){
-    zCsr += sqlite3PutVarint(zCsr, sqlite3VdbeSerialType(pRowid));
+    zCsr += sqlite3PutVarint(zCsr, sqlite3VdbeSerialType(pRowid, 0));
   }
   for(pRec=pData0; pRec<=pTos; pRec++){
-    zCsr += sqlite3VdbeSerialPut(zCsr, pRec);  /* serial data */
+    zCsr += sqlite3VdbeSerialPut(zCsr, pRec, file_format);  /* serial data */
   }
   if( addRowid ){
-    zCsr += sqlite3VdbeSerialPut(zCsr, pRowid);
+    zCsr += sqlite3VdbeSerialPut(zCsr, pRowid, 0);
   }
   assert( zCsr==(zNewRecord+nByte) );
 
@@ -2515,6 +2517,7 @@ case OP_OpenWrite: {       /* no-push */
   Btree *pX;
   int iDb;
   Cursor *pCur;
+  Db *pDb;
   
   assert( pTos>=p->aStack );
   sqlite3VdbeMemIntegerify(pTos);
@@ -2522,9 +2525,17 @@ case OP_OpenWrite: {       /* no-push */
   assert( (pTos->flags & MEM_Dyn)==0 );
   pTos--;
   assert( iDb>=0 && iDb<db->nDb );
-  pX = db->aDb[iDb].pBt;
+  pDb = &db->aDb[iDb];
+  pX = pDb->pBt;
   assert( pX!=0 );
-  wrFlag = pOp->opcode==OP_OpenWrite;
+  if( pOp->opcode==OP_OpenWrite ){
+    wrFlag = 1;
+    if( pDb->file_format < p->minWriteFileFormat ){
+      p->minWriteFileFormat = pDb->file_format;
+    }
+  }else{
+    wrFlag = 0;
+  }
   if( p2<=0 ){
     assert( pTos>=p->aStack );
     sqlite3VdbeMemIntegerify(pTos);
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index 10f3e0660..5871bf296 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -307,6 +307,7 @@ struct Vdbe {
   u8 changeCntOn;         /* True to update the change-counter */
   u8 aborted;             /* True if ROLLBACK in another VM causes an abort */
   u8 expired;             /* True if the VM needs to be recompiled */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
   int nChange;            /* Number of db changes made since last reset */
   i64 startTime;          /* Time when query started - used for profiling */
 };
@@ -332,8 +333,8 @@ void sqlite3VdbePrintOp(FILE*, int, Op*);
 void sqlite3VdbePrintSql(Vdbe*);
 #endif
 int sqlite3VdbeSerialTypeLen(u32);
-u32 sqlite3VdbeSerialType(Mem*);
-int sqlite3VdbeSerialPut(unsigned char*, Mem*);
+u32 sqlite3VdbeSerialType(Mem*, int);
+int sqlite3VdbeSerialPut(unsigned char*, Mem*, int);
 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
 
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 4f291e385..33652fbe6 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -782,6 +782,7 @@ void sqlite3VdbeMakeReady(
   p->explain |= isExplain;
   p->magic = VDBE_MAGIC_RUN;
   p->nChange = 0;
+  p->minWriteFileFormat = 255;
 #ifdef VDBE_PROFILE
   {
     int i;
@@ -1490,7 +1491,9 @@ int sqlite3VdbeCursorMoveto(Cursor *p){
 **      5                     6            signed integer
 **      6                     8            signed integer
 **      7                     8            IEEE float
-**     8-11                                reserved for expansion
+**      8                     0            Integer constant 0
+**      9                     0            Integer constant 1
+**     10,11                               reserved for expansion
 **    N>=12 and even       (N-12)/2        BLOB
 **    N>=13 and odd        (N-13)/2        text
 **
@@ -1499,7 +1502,7 @@ int sqlite3VdbeCursorMoveto(Cursor *p){
 /*
 ** Return the serial-type for the value stored in pMem.
 */
-u32 sqlite3VdbeSerialType(Mem *pMem){
+u32 sqlite3VdbeSerialType(Mem *pMem, int file_format){
   int flags = pMem->flags;
 
   if( flags&MEM_Null ){
@@ -1509,7 +1512,11 @@ u32 sqlite3VdbeSerialType(Mem *pMem){
     /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
 #   define MAX_6BYTE ((((i64)0x00001000)<<32)-1)
     i64 i = pMem->i;
-    u64 u = i<0 ? -i : i;
+    u64 u;
+    if( file_format>=4 && (i&1)==i ){
+      return 8+i;
+    }
+    u = i<0 ? -i : i;
     if( u<=127 ) return 1;
     if( u<=32767 ) return 2;
     if( u<=8388607 ) return 3;
@@ -1548,17 +1555,12 @@ int sqlite3VdbeSerialTypeLen(u32 serial_type){
 ** buf. It is assumed that the caller has allocated sufficient space.
 ** Return the number of bytes written.
 */ 
-int sqlite3VdbeSerialPut(unsigned char *buf, Mem *pMem){
-  u32 serial_type = sqlite3VdbeSerialType(pMem);
+int sqlite3VdbeSerialPut(unsigned char *buf, Mem *pMem, int file_format){
+  u32 serial_type = sqlite3VdbeSerialType(pMem, file_format);
   int len;
 
-  /* NULL */
-  if( serial_type==0 ){
-    return 0;
-  }
- 
   /* Integer and Real */
-  if( serial_type<=7 ){
+  if( serial_type<=7 && serial_type>0 ){
     u64 v;
     int i;
     if( serial_type==7 ){
@@ -1573,12 +1575,16 @@ int sqlite3VdbeSerialPut(unsigned char *buf, Mem *pMem){
     }
     return len;
   }
-  
+
   /* String or blob */
-  assert( serial_type>=12 );
-  len = sqlite3VdbeSerialTypeLen(serial_type);
-  memcpy(buf, pMem->z, len);
-  return len;
+  if( serial_type>=12 ){
+    len = sqlite3VdbeSerialTypeLen(serial_type);
+    memcpy(buf, pMem->z, len);
+    return len;
+  }
+
+  /* NULL or constants 0 or 1 */
+  return 0;
 }
 
 /*
@@ -1591,8 +1597,6 @@ int sqlite3VdbeSerialGet(
   Mem *pMem                     /* Memory cell to write value into */
 ){
   switch( serial_type ){
-    case 8:    /* Reserved for future use */
-    case 9:    /* Reserved for future use */
     case 10:   /* Reserved for future use */
     case 11:   /* Reserved for future use */
     case 0: {  /* NULL */
@@ -1651,6 +1655,12 @@ int sqlite3VdbeSerialGet(
       }
       return 8;
     }
+    case 8:    /* Integer 0 */
+    case 9: {  /* Integer 1 */
+      pMem->i = serial_type-8;
+      pMem->flags = MEM_Int;
+      return 0;
+    }
     default: {
       int len = (serial_type-12)/2;
       pMem->z = (char *)buf;