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Get group_concat() to handle varying separator lengths when windowing

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FossilOrigin-Name: 98e0f2bf67cdee1da1edadeb54ff8564728b3f28fc821e46e8de201247c3fc87
This commit is contained in:
larrybr
2021-09-29 00:32:13 +00:00
parent 76ec55fddb
commit dde13e6f88
4 changed files with 108 additions and 37 deletions
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116
src/func.c
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@@ -1716,23 +1716,36 @@ static void minMaxFinalize(sqlite3_context *context){
/*
** group_concat(EXPR, ?SEPARATOR?)
*/
typedef struct {
StrAccum str; /* The accumulated concatenation */
#ifndef SQLITE_OMIT_WINDOWFUNC
int nAccum; /* Number of strings presently concatenated */
int nFirstSepLength; /* Used to detect separator length change */
/* If pnSepLengths!=0, refs an array of inter-string separator lengths,
* stored as actually incorporated into presently accumulated result.
* (Hence, its slots in use number nAccum-1 between method calls.)
* If pnSepLengths==0, nFirstSepLength is the length used throughout.
*/
int *pnSepLengths;
#endif
} GroupConcatCtx;
static void groupConcatStep(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *zVal;
StrAccum *pAccum;
GroupConcatCtx *pGCC;
const char *zSep;
int nVal, nSep;
assert( argc==1 || argc==2 );
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
pAccum = (StrAccum*)sqlite3_aggregate_context(context, sizeof(*pAccum));
if( pAccum ){
pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
if( pGCC ){
sqlite3 *db = sqlite3_context_db_handle(context);
int firstTerm = pAccum->mxAlloc==0;
pAccum->mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
int firstTerm = pGCC->str.mxAlloc==0;
pGCC->str.mxAlloc = db->aLimit[SQLITE_LIMIT_LENGTH];
if( !firstTerm ){
if( argc==2 ){
zSep = (char*)sqlite3_value_text(argv[1]);
@@ -1741,49 +1754,92 @@ static void groupConcatStep(
zSep = ",";
nSep = 1;
}
if( zSep ) sqlite3_str_append(pAccum, zSep, nSep);
if( zSep )
sqlite3_str_append(&pGCC->str, zSep, nSep);
#ifndef SQLITE_OMIT_WINDOWFUNC
else
nSep = 0;
if( nSep != pGCC->nFirstSepLength || pGCC->pnSepLengths != 0 ){
int * pnsl = pGCC->pnSepLengths;
if( pnsl == 0 ){
/* First separator length variation seen, start tracking them. */
pnsl = (int*)sqlite3_malloc64((pGCC->nAccum+1) * sizeof(int));
if( pnsl!=0 ){
int i = 0, nA = pGCC->nAccum-1;
while( i<nA ) pnsl[i++] = pGCC->nFirstSepLength;
}
}else{
pnsl = (int*)sqlite3_realloc64(pnsl, pGCC->nAccum * sizeof(int));
}
if( pnsl!=0 ){
if( pGCC->nAccum>0 )
pnsl[pGCC->nAccum-1] = nSep;
pGCC->pnSepLengths = pnsl;
}else{
setStrAccumError(&pGCC->str, SQLITE_NOMEM);
}
}
#endif
}
#ifndef SQLITE_OMIT_WINDOWFUNC
else{
pGCC->nFirstSepLength = (argc==2)? sqlite3_value_bytes(argv[1]) : 1;
}
pGCC->nAccum += 1;
#endif
zVal = (char*)sqlite3_value_text(argv[0]);
nVal = sqlite3_value_bytes(argv[0]);
if( zVal ) sqlite3_str_append(pAccum, zVal, nVal);
if( zVal ) sqlite3_str_append(&pGCC->str, zVal, nVal);
}
}
#ifndef SQLITE_OMIT_WINDOWFUNC
static void groupConcatInverse(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int n;
StrAccum *pAccum;
GroupConcatCtx *pGCC;
assert( argc==1 || argc==2 );
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
pAccum = (StrAccum*)sqlite3_aggregate_context(context, sizeof(*pAccum));
/* pAccum is always non-NULL since groupConcatStep() will have always
pGCC = (GroupConcatCtx*)sqlite3_aggregate_context(context, sizeof(*pGCC));
/* pGCC is always non-NULL since groupConcatStep() will have always
** run frist to initialize it */
if( ALWAYS(pAccum) ){
n = sqlite3_value_bytes(argv[0]);
if( argc==2 ){
n += sqlite3_value_bytes(argv[1]);
if( ALWAYS(pGCC) ){
int nVS = sqlite3_value_bytes(argv[0]);
pGCC->nAccum -= 1;
if( pGCC->pnSepLengths!=0 ){
assert(pGCC->nAccum >= 0);
if( pGCC->nAccum>0 ){
nVS += *pGCC->pnSepLengths;
memmove(pGCC->pnSepLengths, pGCC->pnSepLengths+1,
(pGCC->nAccum-1)*sizeof(int));
}
}else{
n++;
/* If removing single accumulated string, harmlessly over-do. */
nVS += pGCC->nFirstSepLength;
}
if( n>=(int)pAccum->nChar ){
pAccum->nChar = 0;
if( nVS>=(int)pGCC->str.nChar ){
pGCC->str.nChar = 0;
}else{
pAccum->nChar -= n;
memmove(pAccum->zText, &pAccum->zText[n], pAccum->nChar);
pGCC->str.nChar -= nVS;
memmove(pGCC->str.zText, &pGCC->str.zText[nVS], pGCC->str.nChar);
}
if( pGCC->str.nChar==0 ){
pGCC->str.mxAlloc = 0;
sqlite3_free(pGCC->pnSepLengths);
pGCC->pnSepLengths = 0;
}
if( pAccum->nChar==0 ) pAccum->mxAlloc = 0;
}
}
#else
# define groupConcatInverse 0
#endif /* SQLITE_OMIT_WINDOWFUNC */
static void groupConcatFinalize(sqlite3_context *context){
StrAccum *pAccum;
pAccum = sqlite3_aggregate_context(context, 0);
if( pAccum ){
GroupConcatCtx *pGCC
= (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
if( pGCC ){
StrAccum *pAccum = &pGCC->str;
if( pAccum->accError==SQLITE_TOOBIG ){
sqlite3_result_error_toobig(context);
}else if( pAccum->accError==SQLITE_NOMEM ){
@@ -1792,13 +1848,17 @@ static void groupConcatFinalize(sqlite3_context *context){
sqlite3_result_text(context, sqlite3StrAccumFinish(pAccum), -1,
sqlite3_free);
}
#ifndef SQLITE_OMIT_WINDOWFUNC
sqlite3_free(pGCC->pnSepLengths);
#endif
}
}
#ifndef SQLITE_OMIT_WINDOWFUNC
static void groupConcatValue(sqlite3_context *context){
sqlite3_str *pAccum;
pAccum = (sqlite3_str*)sqlite3_aggregate_context(context, 0);
if( pAccum ){
GroupConcatCtx *pGCC
= (GroupConcatCtx*)sqlite3_aggregate_context(context, 0);
if( pGCC ){
StrAccum *pAccum = &pGCC->str;
if( pAccum->accError==SQLITE_TOOBIG ){
sqlite3_result_error_toobig(context);
}else if( pAccum->accError==SQLITE_NOMEM ){