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speed up match finding?

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i need to benchmark it
This commit is contained in:
tildearrow 2025-04-09 04:34:22 -05:00
parent 51f133036d
commit 71be28a195
1 changed files with 33 additions and 31 deletions
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64
src/engine/cmdStreamOps.cpp
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@ -794,10 +794,41 @@ SafeWriter* findSubBlocks(SafeWriter* stream, std::vector<SafeWriter*>& subBlock
// search for small matches, and then find bigger ones // search for small matches, and then find bigger ones
logD("finding possible matches"); logD("finding possible matches");
for (size_t i=0; i<stream->size(); i+=8) { for (size_t i=0; i<stream->size(); i+=8) {
if ((i&8191)==0) logV("%d of %d",i,(int)stream->size());
for (size_t j=i+matchSize; j<stream->size(); j+=8) { for (size_t j=i+matchSize; j<stream->size(); j+=8) {
if (memcmp(&buf[i],&buf[j],matchSize)==0) { if (memcmp(&buf[i],&buf[j],matchSize)==0) {
// store this match for later BlockMatch b=BlockMatch(i,j,matchSize);
matches.push_back(BlockMatch(i,j,matchSize));
// determine match size
size_t finalLen=b.len;
size_t origPos=b.orig+b.len;
size_t blockPos=b.block+b.len;
while (true) {
if (origPos>=stream->size() || blockPos>=stream->size()) {
break;
}
if (buf[origPos]!=buf[blockPos]) {
break;
}
origPos++;
blockPos++;
finalLen++;
}
finalLen&=~7;
b.len=finalLen;
b.done=true;
// if this match is bigger than the match size, change the match size
// we're only going to work on the largest matches anyway
if (finalLen>matchSize) {
logW("expand dong");
matchSize=finalLen;
}
// store this match
matches.push_back(b);
} }
} }
} }
@ -807,35 +838,6 @@ SafeWriter* findSubBlocks(SafeWriter* stream, std::vector<SafeWriter*>& subBlock
// quit if there isn't anything // quit if there isn't anything
if (matches.empty()) return stream; if (matches.empty()) return stream;
// search for bigger matches
for (size_t i=0; i<matches.size(); i++) {
if ((i&8191)==0) logV("match %d of %d",i,(int)matches.size());
BlockMatch& b=matches[i];
// don't do anything if this match is done
if (b.done) continue;
size_t finalLen=b.len;
size_t origPos=b.orig+b.len;
size_t blockPos=b.block+b.len;
while (true) {
if (origPos>=stream->size() || blockPos>=stream->size()) {
break;
}
if (buf[origPos]!=buf[blockPos]) {
break;
}
origPos++;
blockPos++;
finalLen++;
}
finalLen&=~7;
b.len=finalLen;
b.done=true;
}
logD("checking overlapping/bad matches"); logD("checking overlapping/bad matches");
// first stage done // first stage done