--- /dev/null
+/******************************************************************************
+ * Copyright (C) 2009 Niko Välimäki *
+ * *
+ * *
+ * This program is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU Lesser General Public License as published *
+ * by the Free Software Foundation; either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program 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 Lesser General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU Lesser General Public License *
+ * along with this program; if not, write to the *
+ * Free Software Foundation, Inc., *
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
+ *****************************************************************************/
+
+#ifndef _TextStorage_H_
+#define _TextStorage_H_
+
+#include "incbwt/bits/deltavector.h"
+
+namespace SXSI
+{
+
+/**
+ * Text collection that supports fast extraction.
+ */
+class TextStorage
+{
+public:
+ // Define a shortcut
+ typedef TextCollection::TextPosition TextPosition;
+ // Block size in DeltaVector
+ const static CSA::usint DV_BLOCK_SIZE = 16;
+
+
+ TextStorage(uchar *text, TextPosition n)
+ : n_(n), text_(text), offsets_(0), numberOfTexts_(0)
+ {
+ initOffsets();
+ }
+
+ TextStorage(FILE *file)
+ : n_(0), text_(0), offsets_(0), numberOfTexts_(0)
+ {
+ if (std::fread(&(this->n_), sizeof(TextPosition), 1, file) != 1)
+ throw std::runtime_error("TextStorage::Load(): file read error (n_).");
+
+ text_ = new uchar[n_];
+ if (std::fread(this->text_, sizeof(uchar), n_, file) != n_)
+ throw std::runtime_error("TextStorage::Load(): file read error (text_).");
+
+ initOffsets();
+ }
+
+ void Save(FILE *file)
+ {
+ if (std::fwrite(&(this->n_), sizeof(TextPosition), 1, file) != 1)
+ throw std::runtime_error("TextStorage::Save(): file write error (n_).");
+
+ if (std::fwrite(this->text_, sizeof(uchar), n_, file) != n_)
+ throw std::runtime_error("TextStorage::Save(): file write error (text_).");
+ }
+
+ ~TextStorage()
+ {
+ delete offsets_;
+ offsets_ = 0;
+ delete [] text_;
+ text_ = 0;
+ n_ = 0;
+ }
+
+ uchar * GetText(TextCollection::DocId docId)
+ {
+ assert(docId < numberOfTexts_);
+
+ TextPosition offset = offsets_->select(docId);
+ return &text_[offset];
+ }
+
+
+
+private:
+ void initOffsets()
+ {
+ // Delta encoded bitvector of text offsets.
+ CSA::DeltaEncoder encoder(DV_BLOCK_SIZE);
+ encoder.setBit(0); // Start of the first text.
+
+ // Read offsets by finding text end positions:
+ for (TextPosition i = 0; i < n_ - 1; ++i)
+ if (text_[i] == '\0')
+ encoder.setBit(i+1);
+
+ offsets_ = new CSA::DeltaVector(encoder, n_);
+ numberOfTexts_ = offsets_->rank(n_ - 1);
+ }
+
+ TextPosition n_;
+ uchar *text_; // FIXME Replace with a succinct representation.
+ CSA::DeltaVector *offsets_;
+ TextPosition numberOfTexts_;
+}; // class TextStorage
+
+
+/**
+ * Builder for TextStorage class
+ */
+class TextStorageBuilder
+{
+public:
+ // Define a shortcut
+ typedef TextCollection::TextPosition TextPosition;
+
+ // Build up simple uchar array
+ explicit TextStorageBuilder(TextPosition n)
+ : n_(n), text_(new uchar [n]), freeText(true)
+ { }
+
+ ~TextStorageBuilder()
+ {
+ if (freeText)
+ delete [] text_;
+ text_ = 0;
+ n_ = 0;
+ }
+
+ // Write access to text[]
+ uchar& operator[] (TextPosition i)
+ {
+ return text_[i];
+ }
+
+ // Init TextStorage
+ TextStorage * InitTextStorage()
+ {
+ freeText = false; // Passing text to TextStorage.
+ return new TextStorage(text_, n_);
+ }
+
+private:
+ TextPosition n_;
+ uchar *text_; // FIXME Replace with a succinct representation.
+ bool freeText;
+}; // class TextStorageBuilder
+
+} // namespace SXSI
+
+#endif // #ifndef _TextStorage_H_