/*
* Copyright 2012 Steven Gribble
*
* This file is part of the UW CSE 333 course project sequence
* (333proj).
*
* 333proj 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.
*
* 333proj 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 333proj. If not, see .
*/
#ifndef HW3_DOCIDTABLEREADER_H_
#define HW3_DOCIDTABLEREADER_H_
#include // for std::list
#include // for (FILE*)
#include "./HashTableReader.h"
#include "./LayoutStructs.h"
using std::list;
namespace hw3 {
// A DocIDTableReader (a derived class of HashTableReader) is used to read one
// of the many the embedded docid --> positions "docIDtable" tables within the
// index file.
class DocIDTableReader : protected HashTableReader {
public:
// Construct a new DocIDTableReader at a specific offset with an
// index file.
// Arguments:
// - f: an open (FILE*) for the underlying index file. The
// constructed object takes ownership of the (FILE*) and will
// fclose() it on destruction.
// - offset: the `docIDtable`'s byte offset within the file.
DocIDTableReader(FILE* f, IndexFileOffset_t offset);
~DocIDTableReader() { }
// Lookup a docID and get back a `std::list`
// containing the positions listed for that docID.
//
// Arguments:
// - doc_id: the docID to look for within the `docIDtable`.
// - ret_val: (output parameter) a `list` with the
// positions of the word in the document. If docID is not found, nothing
// is saved into `*ret_val`.
//
// Returns:
// - true if the docID is found, false otherwise.
bool LookupDocID(const DocID_t& doc_id,
list* const ret_val) const;
// Reads all docID's from the docIDtable and builds a `DocIDElementHeader`
// for each docID and the number of word positions a docID has.
//
// Returns:
// - A list including all docID's from the table
list GetDocIDList() const;
private:
// This friend declaration is here so that the Test_DocIDTableReader
// unit test fixture can access protected member variables of
// DocIDTableReader. See test_docidtablereader.h for details.
friend class Test_DocIDTableReader;
DISALLOW_COPY_AND_ASSIGN(DocIDTableReader);
};
} // namespace hw3
#endif // HW3_DOCIDTABLEREADER_H_