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Overview
| Comment: | Performance optimizations to the editdist3() function in the spellfix extension. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
70d304dcbac4c3fd5e3b96108bffea2c |
| User & Date: | drh 2018-02-14 20:58:36 |
Context
|
2018-02-14
| ||
| 23:27 | Add the --readonly option to the ".open" command in the CLI. (check-in: 06870bb1 user: drh tags: trunk) | |
| 20:58 | Performance optimizations to the editdist3() function in the spellfix extension. (check-in: 70d304dc user: drh tags: trunk) | |
| 20:25 | Disable assert() in the spellfix extension if not compiled with SQLITE_DEBUG. (check-in: 3c53ee0f user: drh tags: trunk) | |
Changes
Changes to ext/misc/spellfix.c.
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int nTo = zTo ? sqlite3_column_bytes(pStmt, 2) : 0;
int iCost = sqlite3_column_int(pStmt, 3);
assert( zFrom!=0 || nFrom==0 );
assert( zTo!=0 || nTo==0 );
if( nFrom>100 || nTo>100 ) continue;
if( iCost<0 ) continue;
if( pLang==0 || iLang!=iLangPrev ){
EditDist3Lang *pNew;
pNew = sqlite3_realloc64(p->a, (p->nLang+1)*sizeof(p->a[0]));
if( pNew==0 ){ rc = SQLITE_NOMEM; break; }
p->a = pNew;
pLang = &p->a[p->nLang];
p->nLang++;
................................................................................
EditDist3FromString *pStr, /* Left hand string */
int n1, /* Index of comparison character on the left */
const char *z2, /* Right-handl comparison character */
int n2 /* Bytes remaining in z2[] */
){
int b1 = pStr->a[n1].nByte;
if( b1>n2 ) return 0;
if( memcmp(pStr->z+n1, z2, b1)!=0 ) return 0;
return 1;
}
/*
** Delete an EditDist3FromString objecct
*/
static void editDist3FromStringDelete(EditDist3FromString *p){
................................................................................
}
return pStr;
}
/*
** Update entry m[i] such that it is the minimum of its current value
** and m[j]+iCost.
**
** If the iCost is 1,000,000 or greater, then consider the cost to be
** infinite and skip the update.
*/
static void updateCost(
unsigned int *m,
int i,
int j,
int iCost
){
assert( iCost>=0 );
if( iCost<10000 ){
unsigned int b = m[j] + iCost;
if( b<m[i] ) m[i] = b;
}
}
/*
** How much stack space (int bytes) to use for Wagner matrix in
** editDist3Core(). If more space than this is required, the entire
** matrix is taken from the heap. To reduce the load on the memory
** allocator, make this value as large as practical for the
|
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int nTo = zTo ? sqlite3_column_bytes(pStmt, 2) : 0;
int iCost = sqlite3_column_int(pStmt, 3);
assert( zFrom!=0 || nFrom==0 );
assert( zTo!=0 || nTo==0 );
if( nFrom>100 || nTo>100 ) continue;
if( iCost<0 ) continue;
if( iCost>10000 ) continue; /* Costs above 10K are considered infinite */
if( pLang==0 || iLang!=iLangPrev ){
EditDist3Lang *pNew;
pNew = sqlite3_realloc64(p->a, (p->nLang+1)*sizeof(p->a[0]));
if( pNew==0 ){ rc = SQLITE_NOMEM; break; }
p->a = pNew;
pLang = &p->a[p->nLang];
p->nLang++;
................................................................................
EditDist3FromString *pStr, /* Left hand string */
int n1, /* Index of comparison character on the left */
const char *z2, /* Right-handl comparison character */
int n2 /* Bytes remaining in z2[] */
){
int b1 = pStr->a[n1].nByte;
if( b1>n2 ) return 0;
if( strncmp(pStr->z+n1, z2, b1)!=0 ) return 0;
return 1;
}
/*
** Delete an EditDist3FromString objecct
*/
static void editDist3FromStringDelete(EditDist3FromString *p){
................................................................................
}
return pStr;
}
/*
** Update entry m[i] such that it is the minimum of its current value
** and m[j]+iCost.
*/
static void updateCost(
unsigned int *m,
int i,
int j,
int iCost
){
unsigned int b;
assert( iCost>=0 );
assert( iCost<10000 );
b = m[j] + iCost;
if( b<m[i] ) m[i] = b;
}
/*
** How much stack space (int bytes) to use for Wagner matrix in
** editDist3Core(). If more space than this is required, the entire
** matrix is taken from the heap. To reduce the load on the memory
** allocator, make this value as large as practical for the
|