database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-11 01:42:22 +03:00
Code Activity

Performance optimization in jsonAppendString().

Browse Source 
FossilOrigin-Name: fdf00e96239c73fb67e2acecc5b95f55a1fc51c3deed4512613c0d6070ce5805
This commit is contained in:
drh
2023-12-02 14:16:47 +00:00
parent 679c90850c
commit f0b8b16317
3 changed files with 34 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/json.c
View File

@@ -595,17 +595,33 @@ static void jsonAppendSeparator(JsonString *p){
** string.
*/
static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
u32 i;
if( zIn==0 ) return;
u32 k;
u8 c;
const u8 *z = (const u8*)zIn;
if( z==0 ) return;
if( (N+p->nUsed+2 >= p->nAlloc) && jsonStringGrow(p,N+2)!=0 ) return;
p->zBuf[p->nUsed++] = '"';
for(i=0; i<N; i++){
unsigned char c = ((unsigned const char*)zIn)[i];
if( jsonIsOk[c] ){
p->zBuf[p->nUsed++] = c;
}else if( c=='"' || c=='\\' ){
while( 1 /*exit-by-break*/ ){
k = 0;
while( k<N-1 && jsonIsOk[z[k]] && jsonIsOk[z[k+1]] ){ k += 2; }
while( k<N && jsonIsOk[z[k]] ){ k++; }
if( k>=N ){
if( k>0 ){
memcpy(&p->zBuf[p->nUsed], z, k);
p->nUsed += k;
}
break;
}
if( k>0 ){
memcpy(&p->zBuf[p->nUsed], z, k);
p->nUsed += k;
z += k;
N -= k;
}
c = z[0];
if( c=='"' || c=='\\' ){
json_simple_escape:
if( (p->nUsed+N+3-i > p->nAlloc) && jsonStringGrow(p,N+3-i)!=0 ) return;
if( (p->nUsed+N+3 > p->nAlloc) && jsonStringGrow(p,N+3)!=0 ) return;
p->zBuf[p->nUsed++] = '\\';
p->zBuf[p->nUsed++] = c;
}else if( c=='\'' ){
@@ -626,7 +642,7 @@ static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
c = aSpecial[c];
goto json_simple_escape;
}
if( (p->nUsed+N+7+i > p->nAlloc) && jsonStringGrow(p,N+7-i)!=0 ) return;
if( (p->nUsed+N+7 > p->nAlloc) && jsonStringGrow(p,N+7)!=0 ) return;
p->zBuf[p->nUsed++] = '\\';
p->zBuf[p->nUsed++] = 'u';
p->zBuf[p->nUsed++] = '0';
@@ -634,6 +650,8 @@ static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
p->zBuf[p->nUsed++] = "0123456789abcdef"[c>>4];
p->zBuf[p->nUsed++] = "0123456789abcdef"[c&0xf];
}
z++;
N--;
}
p->zBuf[p->nUsed++] = '"';
assert( p->nUsed<p->nAlloc );