Fix the handling of reserve-bytes so that the maximum value of 255 can be used.

FossilOrigin-Name: 99749d4fd4930ccf15227f67c732266af9e09dd3cabdc0834fb450ef98196441

9 files changed, 28 insertions, 30 deletions

diff --git a/manifest b/manifest
index 6343d8da6..b053ae4c6 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Provide\sthe\sSQLITE_DEFAULT_LEGACY_ALTER_TABLE\scompile-time\soption.
-D 2020-05-06T18:43:57.955
+C Fix\sthe\shandling\sof\sreserve-bytes\sso\sthat\sthe\smaximum\svalue\sof\s255\scan\sbe\sused.
+D 2020-05-07T01:56:57.057
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -471,13 +471,13 @@ F src/alter.c fa2c3be9b0ebecfafb7062072a0ae6eda126d3e5a9fd51b2eded5acd95dc783c
 F src/analyze.c 953a6c43870ccaf080597244e1eeb4dc2ff6cb84f9501b24e46323de36970b61
 F src/attach.c ff2daea0fe62080192e3f262670e4f61f5a86c1e7bea9cec34e960fe79852aa1
 F src/auth.c a3d5bfdba83d25abed1013a8c7a5f204e2e29b0c25242a56bc02bb0c07bf1e06
-F src/backup.c 5e617c087f1c2d6005c2ec694ce80d6e16bc68d906e1b1c556d7c7c2228b636b
+F src/backup.c b1c90cd4110248c8e1273ff4578d3a84c0c34725e1b96dacd4a6294a908702de
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
-F src/btree.c 079ae87477d0d6c9c072b7f1b326e18131d14d486dc3ab729bd9be0f40d31b63
+F src/btree.c b7b9b444d083f135ad0bfe973ba118916a25085160bae4afcbc232886aeb153a
 F src/btree.h 989ef3c33413549e3e148f3dcb46c030f317dac130dc86809ba6b9aa4b16c72a
-F src/btreeInt.h 887cdd2ea7f4a65143074a8a7c8928b0546f8c18dda3c06a408ce7992cbab0c0
-F src/build.c ec6c0bda1e43ef55e5f5121a77ba19fac51fc6585f95ce2da795bcedcf6e8f36
+F src/btreeInt.h 5c8b8749805787313ecf49eb5be3ced1e94bbf8ef54bb01470ce6bd0d5185c67
+F src/build.c 5566b570435d3511a0fd57388c124491b1f74e59561f0c1679fabe74c4c54b7a
 F src/callback.c d0b853dd413255d2e337b34545e54d888ea02f20da5ad0e63585b389624c4a6c
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c e98518d2d3d4029a13c805e07313fb60c877be56db76e90dd5f3af73085d0ce6
@@ -497,7 +497,7 @@ F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 8e4211d04eb460c0694d486c6ba1c068d468c6f653c3f237869a802ad82854de
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 421310045bd78afefb772294a99e50f37d87ae578786a6169074e6291e30d969
-F src/main.c b48ce4de01fac57dddb12a3a67c6da625f236b0cf6db30e6b132b488e5e0cf05
+F src/main.c d832077d7a1e269c7c0e15ae845fcf80690a2880cb6520ef61f182c6631644f1
 F src/malloc.c a3e13b001f988ecec6bdb90c0ea8912c8c786e623724d7098da623d8d01d19b1
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
@@ -526,7 +526,7 @@ F src/parse.y c8eff38606f443d5ba245263fa7abc05e4116d95656e050c4b78e9bfbf931add
 F src/pcache.c 385ff064bca69789d199a98e2169445dc16e4291fa807babd61d4890c3b34177
 F src/pcache.h 4f87acd914cef5016fae3030343540d75f5b85a1877eed1a2a19b9f284248586
 F src/pcache1.c 6596e10baf3d8f84cc1585d226cf1ab26564a5f5caf85a15757a281ff977d51a
-F src/pragma.c 85f763714b192cc26a236e3ec020a9155fe8da248af21eae86c0d1f0f49a0753
+F src/pragma.c 1b0db48177e52b256c003b8dc6ac708b1079a82cded944a23820574586a4731f
 F src/pragma.h 8168e588536bffd95319451f34e9a754dc37d205ebe433031a7813c5b286beae
 F src/prepare.c 8d4d6c8aa6afefc48027c54b41cdf134b4d6bc2fc4badbe483ad7fd9e1728a28
 F src/printf.c 9be6945837c839ba57837b4bc3af349eba630920fa5532aa518816defe42a7d4
@@ -604,7 +604,7 @@ F src/update.c 3eb778c42155d944377a4ee5e440b04520f07094804ed6ce63d2528f619614d9
 F src/upsert.c 2920de71b20f04fe25eb00b655d086f0ba60ea133c59d7fa3325c49838818e78
 F src/utf.c 95fb6e03a5ca679045c5adccd05380f0addccabef5911abddcb06af069500ab7
 F src/util.c 3b6cedf7a0c69bd6e1acce832873952d416212d6293b18d03064e07d7a9b5118
-F src/vacuum.c f25d3b39681595e321a8a4e7fca3e5971cb14a401213d0742c9bf7d4ce8c2a1a
+F src/vacuum.c de9780b89fa4ee74c3534f60b94820e3179aca759ffc1338ee53cb4ea7693dd3
 F src/vdbe.c e3dba0dee25bc92e871c13cac655260912b3be4abcc85b439259c9934b208da3
 F src/vdbe.h 07b8c636a87df8b6e58f29d6badd7f10d5844353deff1d7c88ed1c2bfe3bbd35
 F src/vdbeInt.h 571413068b5ac07e2ed8ca7a02fa529622fd5455ae6981498376e5e492d2e5ef
@@ -1863,7 +1863,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 9a84d8eb44b12ddea921baa73ac3bffa8c8d23a852605dc1dbde37907360bd79
-R 3b4da28cd92dfc3fa916a6592ebd618b
+P 63e659d9a793227604aa95685a8d83cd08305f1d01e135407a3ffc6d54482ab8
+R 40c51b3c9fb1a999bf30ad6cc83f2430
 U drh
-Z 22c2351c8a2c47ecb255c4109b60094d
+Z 4244c9fee796a92a9333ce7d1083a8fb
diff --git a/manifest.uuid b/manifest.uuid
index c14dfaa28..954b434a4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-63e659d9a793227604aa95685a8d83cd08305f1d01e135407a3ffc6d54482ab8
\ No newline at end of file
+99749d4fd4930ccf15227f67c732266af9e09dd3cabdc0834fb450ef98196441
\ No newline at end of file
diff --git a/src/backup.c b/src/backup.c
index 233d0cee7..77e7ed950 100644
--- a/src/backup.c
+++ b/src/backup.c
@@ -112,7 +112,7 @@ static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
 */
 static int setDestPgsz(sqlite3_backup *p){
   int rc;
-  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),-1,0);
+  rc = sqlite3BtreeSetPageSize(p->pDest,sqlite3BtreeGetPageSize(p->pSrc),0,0);
   return rc;
 }
 
diff --git a/src/btree.c b/src/btree.c
index 0e1f7a2dc..961de0ea4 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -2856,19 +2856,17 @@ int sqlite3BtreeSetPagerFlags(
 */
 int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
   int rc = SQLITE_OK;
+  int x;
   BtShared *pBt = p->pBt;
-  assert( nReserve>=-1 && nReserve<=254 );
+  assert( nReserve>=0 && nReserve<=255 );
   sqlite3BtreeEnter(p);
-  if( nReserve>=0 ){
-    pBt->nReserveWanted = nReserve + 1;
-  }
+  pBt->nReserveWanted = nReserve;
+  x = pBt->pageSize - pBt->usableSize;
+  if( nReserve<x ) nReserve = x;
   if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
     sqlite3BtreeLeave(p);
     return SQLITE_READONLY;
   }
-  if( nReserve<0 ){
-    nReserve = pBt->pageSize - pBt->usableSize;
-  }
   assert( nReserve>=0 && nReserve<=255 );
   if( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE &&
         ((pageSize-1)&pageSize)==0 ){
@@ -2919,12 +2917,12 @@ int sqlite3BtreeGetReserveNoMutex(Btree *p){
 ** The amount of reserve can only grow - never shrink.
 */
 int sqlite3BtreeGetRequestedReserve(Btree *p){
-  int n;
+  int n1, n2;
   sqlite3BtreeEnter(p);
-  n = ((int)p->pBt->nReserveWanted) - 1;
-  if( n<0 ) n = sqlite3BtreeGetReserveNoMutex(p);
+  n1 = (int)p->pBt->nReserveWanted;
+  n2 = sqlite3BtreeGetReserveNoMutex(p);
   sqlite3BtreeLeave(p);
-  return n;
+  return n1>n2 ? n1 : n2;
 }
 
 
diff --git a/src/btreeInt.h b/src/btreeInt.h
index 34b33096b..ec25b5466 100644
--- a/src/btreeInt.h
+++ b/src/btreeInt.h
@@ -417,7 +417,7 @@ struct BtShared {
 #endif
   u8 inTransaction;     /* Transaction state */
   u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
-  u8 nReserveWanted;    /* 1 more than desired number of extra bytes per page */
+  u8 nReserveWanted;    /* Desired number of extra bytes per page */
   u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
   u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
   u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
diff --git a/src/build.c b/src/build.c
index cf36766ae..0b47e8e77 100644
--- a/src/build.c
+++ b/src/build.c
@@ -4630,7 +4630,7 @@ int sqlite3OpenTempDatabase(Parse *pParse){
     }
     db->aDb[1].pBt = pBt;
     assert( db->aDb[1].pSchema );
-    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, -1, 0) ){
+    if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize, 0, 0) ){
       sqlite3OomFault(db);
       return 1;
     }
diff --git a/src/main.c b/src/main.c
index 0d7011e7d..9e1a0e9da 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3854,7 +3854,7 @@ int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
     }else if( op==SQLITE_FCNTL_RESERVE_BYTES ){
       int iNew = *(int*)pArg;
       *(int*)pArg = sqlite3BtreeGetRequestedReserve(pBtree);
-      if( iNew>=0 && iNew<=254 ){
+      if( iNew>=0 && iNew<=255 ){
         sqlite3BtreeSetPageSize(pBtree, 0, iNew, 0);
       }
       rc = SQLITE_OK;
diff --git a/src/pragma.c b/src/pragma.c
index 7105f75a9..161a241ef 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -555,7 +555,7 @@ void sqlite3Pragma(
       ** buffer that the pager module resizes using sqlite3_realloc().
       */
       db->nextPagesize = sqlite3Atoi(zRight);
-      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,-1,0) ){
+      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,0,0) ){
         sqlite3OomFault(db);
       }
     }
diff --git a/src/vacuum.c b/src/vacuum.c
index 5c230fbe1..920a98e01 100644
--- a/src/vacuum.c
+++ b/src/vacuum.c
@@ -377,7 +377,7 @@ end_of_vacuum:
   db->nChange = saved_nChange;
   db->nTotalChange = saved_nTotalChange;
   db->mTrace = saved_mTrace;
-  sqlite3BtreeSetPageSize(pMain, -1, -1, 1);
+  sqlite3BtreeSetPageSize(pMain, -1, 0, 1);
 
   /* Currently there is an SQL level transaction open on the vacuum
   ** database. No locks are held on any other files (since the main file