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#include "write_trie_backwards.h"
#include "comptrie_impl.h"
#include "leaf_skipper.h"
#include <util/generic/buffer.h>
#include <util/generic/vector.h>
namespace NCompactTrie {
size_t WriteTrieBackwards(IOutputStream& os, TReverseNodeEnumerator& enumerator, bool verbose) {
if (verbose) {
Cerr << "Writing down the trie..." << Endl;
}
// Rewrite everything from the back, removing unused pieces.
const size_t chunksize = 0x10000;
TVector<char*> resultData;
resultData.push_back(new char[chunksize]);
char* chunkend = resultData.back() + chunksize;
size_t resultLength = 0;
size_t chunkLength = 0;
size_t counter = 0;
TBuffer bufferHolder;
while (enumerator.Move()) {
if (verbose)
ShowProgress(++counter);
size_t bufferLength = 64 + enumerator.GetLeafLength(); // never know how big leaf data can be
bufferHolder.Clear();
bufferHolder.Resize(bufferLength);
char* buffer = bufferHolder.Data();
size_t nodelength = enumerator.RecreateNode(buffer, resultLength);
Y_ASSERT(nodelength <= bufferLength);
resultLength += nodelength;
if (chunkLength + nodelength <= chunksize) {
chunkLength += nodelength;
memcpy(chunkend - chunkLength, buffer, nodelength);
} else { // allocate a new chunk
memcpy(chunkend - chunksize, buffer + nodelength - (chunksize - chunkLength), chunksize - chunkLength);
chunkLength = chunkLength + nodelength - chunksize;
resultData.push_back(new char[chunksize]);
chunkend = resultData.back() + chunksize;
while (chunkLength > chunksize) { // allocate a new chunks
chunkLength -= chunksize;
memcpy(chunkend - chunksize, buffer + chunkLength, chunksize);
resultData.push_back(new char[chunksize]);
chunkend = resultData.back() + chunksize;
}
memcpy(chunkend - chunkLength, buffer, chunkLength);
}
}
if (verbose)
Cerr << counter << Endl;
// Write the whole thing down
while (!resultData.empty()) {
char* chunk = resultData.back();
os.Write(chunk + chunksize - chunkLength, chunkLength);
chunkLength = chunksize;
delete[] chunk;
resultData.pop_back();
}
return resultLength;
}
size_t WriteTrieBackwardsNoAlloc(IOutputStream& os, TReverseNodeEnumerator& enumerator, TOpaqueTrie& trie, EMinimizeMode mode) {
char* data = const_cast<char*>(trie.Data);
char* end = data + trie.Length;
char* pos = end;
TVector<char> buf(64);
while (enumerator.Move()) {
size_t nodeLength = enumerator.RecreateNode(nullptr, end - pos);
if (nodeLength > buf.size())
buf.resize(nodeLength);
size_t realLength = enumerator.RecreateNode(buf.data(), end - pos);
Y_ASSERT(realLength == nodeLength);
pos -= nodeLength;
memcpy(pos, buf.data(), nodeLength);
}
switch (mode) {
case MM_NOALLOC:
os.Write(pos, end - pos);
break;
case MM_INPLACE:
memmove(data, pos, end - pos);
break;
default:
Y_ABORT_UNLESS(false);
}
return end - pos;
}
}
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