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#ifndef TAGSTATS_STRING_STORE_HPP
#define TAGSTATS_STRING_STORE_HPP
/*
Copyright 2012, 2014 Jochen Topf <jochen@topf.org>.
This file is part of Tagstats.
Tagstats is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Tagstats is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Tagstats. If not, see <http://www.gnu.org/licenses/>.
*/
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <list>
#include <stdexcept>
#include <string>
/**
* class StringStore
*
* Storage of lots of strings (const char *). Memory is allocated in chunks.
* If a string is added and there is no space in the current chunk, a new
* chunk will be allocated. Strings added to the store must not be larger
* than the chunk size.
*
* All memory is released when the destructor is called. There is no other way
* to release all or part of the memory.
*
*/
class StringStore {
size_t m_chunk_size;
std::list<std::string> m_chunks;
void add_chunk() {
m_chunks.push_front(std::string());
m_chunks.front().reserve(m_chunk_size);
}
public:
StringStore(size_t chunk_size) :
m_chunk_size(chunk_size),
m_chunks() {
add_chunk();
}
/**
* Add a null terminated string to the store. This will
* automatically get more memory if we are out.
* Returns a pointer to the copy of the string we have
* allocated.
*/
const char* add(const char* string) {
size_t len = std::strlen(string) + 1;
assert(len <= m_chunk_size);
size_t chunk_len = m_chunks.front().size();
if (chunk_len + len > m_chunks.front().capacity()) {
add_chunk();
chunk_len = 0;
}
m_chunks.front().append(string);
m_chunks.front().append(1, '\0');
return m_chunks.front().c_str() + chunk_len;
}
// These functions get you some idea how much memory was
// used.
int get_chunk_size() const {
return m_chunk_size;
}
int get_chunk_count() const {
return m_chunks.size();
}
int get_used_bytes_in_last_chunk() const {
return m_chunks.front().size();
}
};
#endif // TAGSTATS_STRING_STORE_HPP
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