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// Copyright 2011 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This program adds N lines from infile to a leveldb table at outfile.
// The h.txt infile was generated via:
// cat hamlet-act-1.txt | tr '[:upper:]' '[:lower:]' | grep -o -E '\w+' | sort | uniq -c > infile
//
// To build and run:
// g++ make-table.cc -lleveldb && ./a.out
#include <fstream>
#include <iostream>
#include <string>
#include "leveldb/env.h"
#include "leveldb/filter_policy.h"
#include "leveldb/table.h"
#include "leveldb/table_builder.h"
const int N = 1000000;
const char* infile = "h.txt";
const char* outfile = "h.ldb";
int write() {
leveldb::Status status;
leveldb::WritableFile* wf;
status = leveldb::Env::Default()->NewWritableFile(outfile, &wf);
if (!status.ok()) {
std::cerr << "Env::NewWritableFile: " << status.ToString() << std::endl;
return 1;
}
leveldb::Options o;
// o.compression = leveldb::kNoCompression;
// o.filter_policy = leveldb::NewBloomFilterPolicy(10);
leveldb::TableBuilder* tb = new leveldb::TableBuilder(o, wf);
std::ifstream in(infile);
std::string s;
for (int i = 0; i < N && getline(in, s); i++) {
std::string key(s, 8);
std::string val(s, 0, 7);
val = val.substr(1 + val.rfind(' '));
tb->Add(key.c_str(), val.c_str());
}
status = tb->Finish();
if (!status.ok()) {
std::cerr << "TableBuilder::Finish: " << status.ToString() << std::endl;
return 1;
}
status = wf->Close();
if (!status.ok()) {
std::cerr << "WritableFile::Close: " << status.ToString() << std::endl;
return 1;
}
std::cout << "wrote " << tb->NumEntries() << " entries" << std::endl;
delete tb;
delete wf;
return 0;
}
int read() {
leveldb::Status status;
leveldb::RandomAccessFile* raf;
status = leveldb::Env::Default()->NewRandomAccessFile(outfile, &raf);
if (!status.ok()) {
std::cerr << "Env::NewRandomAccessFile: " << status.ToString() << std::endl;
return 1;
}
uint64_t file_size;
status = leveldb::Env::Default()->GetFileSize(outfile, &file_size);
if (!status.ok()) {
std::cerr << "Env::GetFileSize: " << status.ToString() << std::endl;
return 1;
}
leveldb::Options o;
leveldb::Table* t;
status = leveldb::Table::Open(o, raf, file_size, &t);
if (!status.ok()) {
std::cerr << "Table::Open: " << status.ToString() << std::endl;
return 1;
}
leveldb::ReadOptions ro;
leveldb::Iterator* i = t->NewIterator(ro);
uint64_t n = 0;
for (i->SeekToFirst(); i->Valid(); i->Next()) {
n++;
}
std::cout << "read " << n << " entries" << std::endl;
delete i;
delete t;
delete raf;
return 0;
}
int main(int argc, char** argv) {
int ret = write();
if (ret != 0) {
return ret;
}
return read();
}
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