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Get rid of global buffer that would ruin concurrent MapBlock serialization

master
sfan5 2022-05-09 20:00:22 +02:00
parent 5d26ac0088
commit 9a01581cdd
1 changed files with 18 additions and 14 deletions
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32
src/mapblock.cpp
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@ -221,33 +221,36 @@ void MapBlock::expireDayNightDiff()
/*
Serialization
*/
// List relevant id-name pairs for ids in the block using nodedef
// Renumbers the content IDs (starting at 0 and incrementing
// use static memory requires about 65535 * sizeof(int) ram in order to be
// sure we can handle all content ids. But it's absolutely worth it as it's
// a speedup of 4 for one of the major time consuming functions on storing
// mapblocks.
static content_t getBlockNodeIdMapping_mapping[USHRT_MAX + 1];
// Renumbers the content IDs (starting at 0 and incrementing)
static void getBlockNodeIdMapping(NameIdMapping *nimap, MapNode *nodes,
const NodeDefManager *nodedef)
{
memset(getBlockNodeIdMapping_mapping, 0xFF, (USHRT_MAX + 1) * sizeof(content_t));
// The static memory requires about 65535 * sizeof(int) RAM in order to be
// sure we can handle all content ids. But it's absolutely worth it as it's
// a speedup of 4 for one of the major time consuming functions on storing
// mapblocks.
thread_local std::unique_ptr<content_t[]> mapping;
static_assert(sizeof(content_t) == 2, "content_t must be 16-bit");
if (!mapping)
mapping = std::make_unique<content_t[]>(USHRT_MAX + 1);
std::set<content_t> unknown_contents;
memset(mapping.get(), 0xFF, (USHRT_MAX + 1) * sizeof(content_t));
std::unordered_set<content_t> unknown_contents;
content_t id_counter = 0;
for (u32 i = 0; i < MapBlock::nodecount; i++) {
content_t global_id = nodes[i].getContent();
content_t id = CONTENT_IGNORE;
// Try to find an existing mapping
if (getBlockNodeIdMapping_mapping[global_id] != 0xFFFF) {
id = getBlockNodeIdMapping_mapping[global_id];
}
else
{
if (mapping[global_id] != 0xFFFF) {
id = mapping[global_id];
} else {
// We have to assign a new mapping
id = id_counter++;
getBlockNodeIdMapping_mapping[global_id] = id;
mapping[global_id] = id;
const ContentFeatures &f = nodedef->get(global_id);
const std::string &name = f.name;
@ -265,6 +268,7 @@ static void getBlockNodeIdMapping(NameIdMapping *nimap, MapNode *nodes,
<< "Name for node id " << unknown_content << " not known" << std::endl;
}
}
// Correct ids in the block to match nodedef based on names.
// Unknown ones are added to nodedef.
// Will not update itself to match id-name pairs in nodedef.