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Overview
Comment: | Tweaks to comments in btree.c. Minor code changes to enhance testability. |
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Timelines: | family | ancestors | descendants | both | trunk |
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SHA1: |
c7d9aa3a1ce63e27ec94295601bc89fe |
User & Date: | drh 2014-10-30 20:48:44.305 |
Context
2014-10-30
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23:14 | Improvements to the wording of some comments. Reinstate an assert() that is only true for non-corrupt database files by adding an "|| CORRUPT_DB" term. (check-in: 67adb44838 user: drh tags: trunk) | |
20:48 | Tweaks to comments in btree.c. Minor code changes to enhance testability. (check-in: c7d9aa3a1c user: drh tags: trunk) | |
2014-10-29
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18:20 | Fix the %c format character in sqlite3VXPrintf() so that it correctly handles precisions larger than 70. (check-in: 08a27440f1 user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
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1227 1228 1229 1230 1231 1232 1233 | /* ** Search the free-list on page pPg for space to store a cell nByte bytes in ** size. If one can be found, return a pointer to the space and remove it ** from the free-list. ** ** If no suitable space can be found on the free-list, return NULL. ** | | | < < | | | 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 | /* ** Search the free-list on page pPg for space to store a cell nByte bytes in ** size. If one can be found, return a pointer to the space and remove it ** from the free-list. ** ** If no suitable space can be found on the free-list, return NULL. ** ** This function may detect corruption within pPg. If corruption is ** detected then *pRc is set to SQLITE_CORRUPT and NULL is returned. ** ** If a slot of at least nByte bytes is found but cannot be used because ** there are already at least 60 fragmented bytes on the page, return NULL. ** In this case, if pbDefrag parameter is not NULL, set *pbDefrag to true. */ static u8 *pageFindSlot(MemPage *pPg, int nByte, int *pRc, int *pbDefrag){ const int hdr = pPg->hdrOffset; u8 * const aData = pPg->aData; int iAddr; int pc; int usableSize = pPg->pBt->usableSize; for(iAddr=hdr+1; (pc = get2byte(&aData[iAddr]))>0; iAddr=pc){ int size; /* Size of the free slot */ if( pc>usableSize-4 || pc<iAddr+4 ){ *pRc = SQLITE_CORRUPT_BKPT; return 0; } size = get2byte(&aData[pc+2]); if( size>=nByte ){ int x = size - nByte; testcase( x==4 ); testcase( x==3 ); if( x<4 ){ if( aData[hdr+7]>=60 ){ if( pbDefrag ) *pbDefrag = 1; return 0; } /* Remove the slot from the free-list. Update the number of ** fragmented bytes within the page. */ memcpy(&aData[iAddr], &aData[pc], 2); aData[hdr+7] += (u8)x; }else if( size+pc > usableSize ){ *pRc = SQLITE_CORRUPT_BKPT; return 0; }else{ /* The slot remains on the free-list. Reduce its size to account ** for the portion used by the new allocation. */ put2byte(&aData[pc+2], x); } return &aData[pc + x]; |
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6072 6073 6074 6075 6076 6077 6078 6079 | int i; u8 *aData = pPg->aData; u8 *pData = *ppData; const int bFreelist = aData[1] || aData[2]; assert( CORRUPT_DB || pPg->hdrOffset==0 ); /* Never called on page 1 */ for(i=0; i<nCell; i++){ int sz = szCell[i]; u8 *pSlot; | > | | 6070 6071 6072 6073 6074 6075 6076 6077 6078 6079 6080 6081 6082 6083 6084 6085 6086 | int i; u8 *aData = pPg->aData; u8 *pData = *ppData; const int bFreelist = aData[1] || aData[2]; assert( CORRUPT_DB || pPg->hdrOffset==0 ); /* Never called on page 1 */ for(i=0; i<nCell; i++){ int sz = szCell[i]; int rc; u8 *pSlot; if( bFreelist==0 || (pSlot = pageFindSlot(pPg, sz, &rc, 0))==0 ){ pData -= sz; if( pData<pBegin ) return 1; pSlot = pData; } memcpy(pSlot, apCell[i], sz); put2byte(pCellptr, (pSlot - aData)); pCellptr += 2; |
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6866 6867 6868 6869 6870 6871 6872 | aPgno[i] = apNew[i]->pgno; aPgFlags[i] = apNew[i]->pDbPage->flags; for(j=0; j<i; j++){ if( aPgno[j]==aPgno[i] ){ /* This branch is taken if the set of sibling pages somehow contains ** duplicate entries. This can happen if the database is corrupt. ** It would be simpler to detect this as part of the loop below, but | | | > | 6865 6866 6867 6868 6869 6870 6871 6872 6873 6874 6875 6876 6877 6878 6879 6880 6881 | aPgno[i] = apNew[i]->pgno; aPgFlags[i] = apNew[i]->pDbPage->flags; for(j=0; j<i; j++){ if( aPgno[j]==aPgno[i] ){ /* This branch is taken if the set of sibling pages somehow contains ** duplicate entries. This can happen if the database is corrupt. ** It would be simpler to detect this as part of the loop below, but ** we do the detection here in order to avoid populating the pager ** cache with two separate objects associated with the same ** page number. */ assert( CORRUPT_DB ); rc = SQLITE_CORRUPT_BKPT; goto balance_cleanup; } } } for(i=0; i<nNew; i++){ |
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6952 6953 6954 6955 6956 6957 6958 | } if( i==cntNew[iNew] ){ pNew = apNew[++iNew]; if( !leafData ) continue; } /* Cell pCell is destined for new sibling page pNew. Originally, it | | | 6952 6953 6954 6955 6956 6957 6958 6959 6960 6961 6962 6963 6964 6965 6966 | } if( i==cntNew[iNew] ){ pNew = apNew[++iNew]; if( !leafData ) continue; } /* Cell pCell is destined for new sibling page pNew. Originally, it ** was either part of sibling page iOld (possibly an overflow cell), ** or else the divider cell to the left of sibling page iOld. So, ** if sibling page iOld had the same page number as pNew, and if ** pCell really was a part of sibling page iOld (not a divider or ** overflow cell), we can skip updating the pointer map entries. */ if( pNew->pgno!=aPgno[iOld] || pCell<aOld || pCell>=&aOld[usableSize] ){ if( !leafCorrection ){ ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc); |
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