database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-14 00:22:38 +03:00
Code Activity

Performance enhancements and size reduction for sqlite3VXPrintf()

Browse Source 
FossilOrigin-Name: eb071eb58cf675bd6cd9dd46aed9d57fbb7a77e8
This commit is contained in:
drh
2014-03-17 14:24:27 +00:00
parent 18c7e40ca3
commit a70a073b3f
3 changed files with 89 additions and 80 deletions
Download Patch File Download Diff File Expand all files Collapse all files

155
src/printf.c
View File

@@ -134,20 +134,6 @@ static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
}
#endif /* SQLITE_OMIT_FLOATING_POINT */
/*
** Append N space characters to the given string buffer.
*/
void sqlite3AppendSpace(StrAccum *pAccum, int N){
static const char zSpaces[] = " ";
while( N>=(int)sizeof(zSpaces)-1 ){
sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
N -= sizeof(zSpaces)-1;
}
if( N>0 ){
sqlite3StrAccumAppend(pAccum, zSpaces, N);
}
}
/*
** Set the StrAccum object to an error mode.
*/
@@ -237,11 +223,9 @@ void sqlite3VXPrintf(
}
for(; (c=(*fmt))!=0; ++fmt){
if( c!='%' ){
int amt;
bufpt = (char *)fmt;
amt = 1;
while( (c=(*++fmt))!='%' && c!=0 ) amt++;
sqlite3StrAccumAppend(pAccum, bufpt, amt);
while( (c=(*++fmt))!='%' && c!=0 ){};
sqlite3StrAccumAppend(pAccum, bufpt, (int)(fmt - bufpt));
if( c==0 ) break;
}
if( (c=(*++fmt))==0 ){
@@ -729,29 +713,89 @@ void sqlite3VXPrintf(
** "length" characters long. The field width is "width". Do
** the output.
*/
if( !flag_leftjustify ){
register int nspace;
nspace = width-length;
if( nspace>0 ){
sqlite3AppendSpace(pAccum, nspace);
}
}
if( length>0 ){
sqlite3StrAccumAppend(pAccum, bufpt, length);
}
if( flag_leftjustify ){
register int nspace;
nspace = width-length;
if( nspace>0 ){
sqlite3AppendSpace(pAccum, nspace);
}
}
width -= length;
if( width>0 && !flag_leftjustify ) sqlite3AppendSpace(pAccum, width);
sqlite3StrAccumAppend(pAccum, bufpt, length);
if( width>0 && flag_leftjustify ) sqlite3AppendSpace(pAccum, width);
if( zExtra ) sqlite3_free(zExtra);
}/* End for loop over the format string */
} /* End of function */
/*
** Append N bytes of text from z to the StrAccum object.
** Enlarge the memory allocation on a StrAccum object so that it is
** able to accept at least N more bytes of text.
**
** Return the number of bytes of text that StrAccum is able to accept
** after the attempted enlargement. The value returned might be zero.
*/
static int sqlite3StrAccumEnlarge(StrAccum *p, int N){
char *zNew;
assert( p->nChar+N >= p->nAlloc ); /* Only called if really needed */
if( p->accError ){
testcase(p->accError==STRACCUM_TOOBIG);
testcase(p->accError==STRACCUM_NOMEM);
return 0;
}
if( !p->useMalloc ){
N = p->nAlloc - p->nChar - 1;
setStrAccumError(p, STRACCUM_TOOBIG);
return N;
}else{
char *zOld = (p->zText==p->zBase ? 0 : p->zText);
i64 szNew = p->nChar;
szNew += N + 1;
if( szNew > p->mxAlloc ){
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_TOOBIG);
return 0;
}else{
p->nAlloc = (int)szNew;
}
if( p->useMalloc==1 ){
zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
}else{
zNew = sqlite3_realloc(zOld, p->nAlloc);
}
if( zNew ){
if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
p->zText = zNew;
}else{
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_NOMEM);
return 0;
}
}
return N;
}
/*
** Append N space characters to the given string buffer.
*/
void sqlite3AppendSpace(StrAccum *p, int N){
if( p->nChar+N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ) return;
while( (N--)>0 ) p->zText[p->nChar++] = ' ';
}
/*
** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
** This is a helper routine to sqlite3StrAccumAppend() that does special-case
** work (enlarging the buffer) using tail recursion, so that the
** sqlite3StrAccumAppend() routine can use fast calling semantics.
*/
static void enlargeAndAppend(StrAccum *p, const char *z, int N){
N = sqlite3StrAccumEnlarge(p, N);
if( N>0 ){
memcpy(&p->zText[p->nChar], z, N);
p->nChar += N;
}
}
/*
** Append N bytes of text from z to the StrAccum object. Increase the
** size of the memory allocation for StrAccum if necessary.
*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
assert( z!=0 );
@@ -759,43 +803,8 @@ void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
assert( N>=0 );
assert( p->accError==0 || p->nAlloc==0 );
if( p->nChar+N >= p->nAlloc ){
char *zNew;
if( p->accError ){
testcase(p->accError==STRACCUM_TOOBIG);
testcase(p->accError==STRACCUM_NOMEM);
return;
}
if( !p->useMalloc ){
N = p->nAlloc - p->nChar - 1;
setStrAccumError(p, STRACCUM_TOOBIG);
if( N<=0 ){
return;
}
}else{
char *zOld = (p->zText==p->zBase ? 0 : p->zText);
i64 szNew = p->nChar;
szNew += N + 1;
if( szNew > p->mxAlloc ){
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_TOOBIG);
return;
}else{
p->nAlloc = (int)szNew;
}
if( p->useMalloc==1 ){
zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
}else{
zNew = sqlite3_realloc(zOld, p->nAlloc);
}
if( zNew ){
if( zOld==0 && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
p->zText = zNew;
}else{
sqlite3StrAccumReset(p);
setStrAccumError(p, STRACCUM_NOMEM);
return;
}
}
enlargeAndAppend(p,z,N);
return;
}
assert( p->zText );
memcpy(&p->zText[p->nChar], z, N);