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parser: Fix performance regression when parsing namespaces

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The namespace hash table didn't reuse deleted buckets, leading to
quadratic behavior.

Also ignore deleted buckets when resizing.

Fixes #726.
This commit is contained in:
Nick Wellnhofer 2024-06-04 16:33:02 +02:00
parent 897c73fe24
commit 122b61309f
1 changed files with 8 additions and 5 deletions
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13
parser.c
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@ -1525,7 +1525,7 @@ xmlParserNsStartElement(xmlParserNsData *nsdb) {
static int
xmlParserNsLookup(xmlParserCtxtPtr ctxt, const xmlHashedString *prefix,
xmlParserNsBucket **bucketPtr) {
xmlParserNsBucket *bucket;
xmlParserNsBucket *bucket, *tombstone;
unsigned index, hashValue;
if (prefix->name == NULL)
@ -1537,10 +1537,13 @@ xmlParserNsLookup(xmlParserCtxtPtr ctxt, const xmlHashedString *prefix,
hashValue = prefix->hashValue;
index = hashValue & (ctxt->nsdb->hashSize - 1);
bucket = &ctxt->nsdb->hash[index];
tombstone = NULL;
while (bucket->hashValue) {
if ((bucket->hashValue == hashValue) &&
(bucket->index != INT_MAX)) {
if (bucket->index == INT_MAX) {
if (tombstone == NULL)
tombstone = bucket;
} else if (bucket->hashValue == hashValue) {
if (ctxt->nsTab[bucket->index * 2] == prefix->name) {
if (bucketPtr != NULL)
*bucketPtr = bucket;
@ -1557,7 +1560,7 @@ xmlParserNsLookup(xmlParserCtxtPtr ctxt, const xmlHashedString *prefix,
}
if (bucketPtr != NULL)
*bucketPtr = bucket;
*bucketPtr = tombstone ? tombstone : bucket;
return(INT_MAX);
}
@ -1798,7 +1801,7 @@ xmlParserNsPush(xmlParserCtxtPtr ctxt, const xmlHashedString *prefix,
unsigned hv = ctxt->nsdb->hash[i].hashValue;
unsigned newIndex;
if (hv == 0)
if ((hv == 0) || (ctxt->nsdb->hash[i].index == INT_MAX))
continue;
newIndex = hv & (newSize - 1);