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Overview
| Comment: | An example showing how to improve performance of sqlite3VdbeSerialPut() using the GCC intrinsic function __builtin_bswap64(). |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | builtin-bswap64 |
| Files: | files | file ages | folders |
| SHA1: |
e42ed9b4adbf4a5cd4ce572d1015f3d2 |
| User & Date: | drh 2017-01-16 11:54:30 |
Context
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2017-01-16
| ||
| 11:54 | An example showing how to improve performance of sqlite3VdbeSerialPut() using the GCC intrinsic function __builtin_bswap64(). Leaf check-in: e42ed9b4 user: drh tags: builtin-bswap64 | |
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2017-01-13
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| 18:24 | Fix a problem preventing resumption of RBU operations after recovering from a process or system failure that occurs during the incremental-checkpoint phase. check-in: 97914266 user: dan tags: trunk | |
Changes
Changes to src/vdbeaux.c.
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**
** Return the number of bytes actually written into buf[]. The number
** of bytes in the zero-filled tail is included in the return value only
** if those bytes were zeroed in buf[].
*/
u32 sqlite3VdbeSerialPut(u8 *buf, Mem *pMem, u32 serial_type){
u32 len;
/* Integer and Real */
if( serial_type<=7 && serial_type>0 ){
u64 v;
u32 i;
if( serial_type==7 ){
assert( sizeof(v)==sizeof(pMem->u.r) );
memcpy(&v, &pMem->u.r, sizeof(v));
swapMixedEndianFloat(v);
}else{
v = pMem->u.i;
}
len = i = sqlite3SmallTypeSizes[serial_type];
assert( i>0 );
do{
buf[--i] = (u8)(v&0xFF);
v >>= 8;
}while( i );
return len;
}
/* String or blob */
if( serial_type>=12 ){
assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.nZero:0)
== (int)sqlite3VdbeSerialTypeLen(serial_type) );
len = pMem->n;
if( len>0 ) memcpy(buf, pMem->z, len);
return len;
}
/* NULL or constants 0 or 1 */
return 0;
}
/* Input "x" is a sequence of unsigned characters that represent a
** big-endian integer. Return the equivalent native integer
*/
#define ONE_BYTE_INT(x) ((i8)(x)[0])
#define TWO_BYTE_INT(x) (256*(i8)((x)[0])|(x)[1])
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**
** Return the number of bytes actually written into buf[]. The number
** of bytes in the zero-filled tail is included in the return value only
** if those bytes were zeroed in buf[].
*/
u32 sqlite3VdbeSerialPut(u8 *buf, Mem *pMem, u32 serial_type){
u32 len;
u64 v;
u32 i;
/* String or blob */
if( serial_type>=12 ){
assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.nZero:0)
== (int)sqlite3VdbeSerialTypeLen(serial_type) );
len = pMem->n;
if( len>0 ) memcpy(buf, pMem->z, len);
return len;
}
/* Integer and Real */
if( serial_type==7 ){
assert( sizeof(v)==sizeof(pMem->u.r) );
memcpy(&v, &pMem->u.r, sizeof(v));
swapMixedEndianFloat(v);
}else{
v = pMem->u.i;
}
len = i = sqlite3SmallTypeSizes[serial_type];
v = __builtin_bswap64(v);
memcpy(buf, &((char*)&v)[8-i], i);
return len;
}
/* Input "x" is a sequence of unsigned characters that represent a
** big-endian integer. Return the equivalent native integer
*/
#define ONE_BYTE_INT(x) ((i8)(x)[0])
#define TWO_BYTE_INT(x) (256*(i8)((x)[0])|(x)[1])
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