mirror of
https://github.com/IfcOpenShell/IfcOpenShell.git
synced 2026-08-09 17:31:45 +00:00
Thomas Krijnen
82 lines
3.6 KiB
C++
82 lines
3.6 KiB
C++
/********************************************************************************
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* *
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* This file is part of IfcOpenShell. *
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* *
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* IfcOpenShell is free software: you can redistribute it and/or modify *
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* it under the terms of the Lesser GNU General Public License as published by *
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* the Free Software Foundation, either version 3.0 of the License, or *
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* (at your option) any later version. *
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* *
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* IfcOpenShell is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* Lesser GNU General Public License for more details. *
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* *
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* You should have received a copy of the Lesser GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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* *
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********************************************************************************/
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/*********************************************************************************
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* *
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* Reads a file in chunks of BUF_SIZE and provides functions to access its *
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* contents randomly and character by character *
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* *
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********************************************************************************/
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#ifndef IFCSPFSTREAM_H
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#define IFCSPFSTREAM_H
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#include <fstream>
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#include <string>
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// As of IfcOpenShell version 0.3.0 the paging functionality, which
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// loads a file on disk into multiple chunks, has been disabled.
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// It proved to be an inefficient way of working with large files,
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// as often these did not facilitate to be parsed in a sequential
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// manner efficiently. To enable the paging functionality uncomment
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// the following statement.
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// #define BUF_SIZE (8 * 1024 * 1024)
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namespace IfcParse {
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/// The IfcSpfStream class represents a ISO 10303-21 IFC-SPF file in memory.
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/// The file is interpreted as a sequence of tokens which are lazily
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/// interpreted only when requested. If the size of the file is
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/// larger than BUF_SIZE, the file is split into seperate pages, of
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/// which only one is simultaneously kept in memory, for files
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/// that define their entities not in a sequential nature, this is
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/// detrimental for the performance of the parser.
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class IfcSpfStream {
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private:
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FILE* stream;
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char* buffer;
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unsigned int ptr;
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unsigned int len;
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void ReadBuffer(bool inc=true);
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#ifdef BUF_SIZE
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unsigned int offset;
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bool paging;
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#endif
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public:
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bool valid;
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bool eof;
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unsigned int size;
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IfcSpfStream(const std::string& fn);
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IfcSpfStream(std::istream& f, int len);
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IfcSpfStream(void* data, int len);
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/// Returns the character at the cursor
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char Peek();
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/// Returns the character at specified offset
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char Read(unsigned int offset);
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/// Increment the file cursor and reads new page if necessary
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void Inc();
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void Close();
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/// Moves the file cursor to an arbitrary offset in the file
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void Seek(unsigned int offset);
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/// Returns the cursor position
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unsigned int Tell();
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};
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}
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#endif
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