diff options
Diffstat (limited to 'reader.cpp')
| -rw-r--r-- | reader.cpp | 363 |
1 files changed, 0 insertions, 363 deletions
diff --git a/reader.cpp b/reader.cpp deleted file mode 100644 index 07e267e..0000000 --- a/reader.cpp +++ /dev/null @@ -1,363 +0,0 @@ -/* $Id: reader.cpp,v 1.10 2006/11/05 04:42:43 ganzhorn Exp $ - * This file is part of lfhex. - * Copyright (C) 2006 Salem Ganzhorn <eyekode@yahoo.com> - * - * This program 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 version 2. - * - * 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 General Public License for more details. - * - * You should have received a copy of the GNU 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. - */ - -#include <stdexcept> -#include <algorithm> -#include <new> - -// for stat: -#include <sys/types.h> -#include <sys/stat.h> -#include <unistd.h> - -// for strerror and errno: -#include <string.h> -#include <errno.h> - -#include <assert.h> - -#include <stdexcept> - -#include "local.h" -#include "reader.hpp" // some systems #define to map fn's to thier 64 bit - // equivalents. make sure the header gets processed the - // same as the .cc file - -Reader::Reader( const string& filename, off_t npages, off_t pageSize ) - : _filename(filename), - _pageSize(pageSize) -{ - _maxPages = _freePages = (npages < 10) ? 10: npages; - _error = ""; - _is_open = false; - _offset = 0; - _size = 0; - _firstPage = -1; - _lastPage = -1; - - if( !filename.empty() ) - open(filename); -} - -Reader::~Reader() -{ - if( _is_open ) - close(); -} - -// -// public methods -// - -bool Reader::open( const string& filename ) -{ - // clear old data - if( is_open() ) { - this->close(); - if( is_open() ) // only occurs if close somehow fails. - return false; - } else { - _is_open = false; - } - - if( 0 == (_fptr = fopen( filename.c_str() , "r" )) ) { - _error = "Failed to open \"" + filename + "\""; - return false; - } - - // get filesize - struct stat statBuf; - if( -1 == stat(filename.c_str(), &statBuf) ) { - _error = "Could not stat \"" + filename + "\""; - return false; - } - - off_t filesize = statBuf.st_size; - _size = filesize; - // calculate necessary number of pages - off_t npages = filesize/_pageSize +1; - // initialize page pointers - _data.resize(npages); - fill( _data.begin(), _data.begin()+npages, (uchar*)0 ); - - _filename = filename; - _is_open = true; - _firstPage = _lastPage = 0; - return loadPage(0); -} - -bool Reader::close() -{ - if( !is_open() ) { - _error = "attempted to close non-open reader."; - return false; - } - - _filename = ""; - _error = ""; - if( EOF == fclose(_fptr) ) { - _error = strerror(errno); - return false; - } - // free data pages - vector<uchar*>::iterator itr; - for( itr = _data.begin(); itr != _data.end(); ++itr ) - delete [] (*itr); - _is_open = false; - _firstPage = _lastPage = -1; - _freePages = _maxPages; - return true; -} - -bool Reader::is_open() const -{ - return _is_open; -} - -size_t Reader::read(vector<uchar>& v, size_t numBytes) -{ - int lastPageIdx = 0; - size_t bytesRead; - - // if we don't have enough bytes left... then set page_end to lastPageIdx - // to the last page and set bytesRead to the remaining number of bytes - if( _offset+numBytes >= size() ) { - _eof = true; - lastPageIdx = _data.size()-1; - bytesRead = size()-tell(); - // we use numBytes as a counter for the number of operations to make - // so limit numBytes to the actual the max number of bytes left - numBytes = bytesRead; - } else { - lastPageIdx = (_offset+numBytes)/_pageSize; - bytesRead = numBytes; - } - - if( !numBytes ) - return numBytes; - - // only do one realloc if necessary - v.erase(v.begin(),v.end()); - v.reserve(v.size()+numBytes); - - // int byte_end; // == lastByteIndex+1 - // copy the data a page at a time - for(int page = _offset/_pageSize; page <= lastPageIdx; page++) { - // ensure the page is loaded. - try { - loadPage( page ); - } - catch (bad_alloc){ - // out of memory - _error = "Out of memory."; - // return the number of bytes read - return (_offset/_pageSize - page)*_pageSize; - } - - int start = _offset%_pageSize; - int stop = (page == lastPageIdx)? start+numBytes: _pageSize; - for(int i = start; i < stop; i++) { - v.push_back(_data[page][i]); - } - numBytes -= stop-start; - _offset += stop-start; - } - return bytesRead; -} -bool Reader::eof() -{ - return (is_open())? _eof : 0; -} -off_t Reader::seek(off_t offset) -{ - if( !is_open() ) - return -1; - - // seek resets eof... even if the seek is past eof - _eof = false; - - _offset = max( min( offset, size()-1 ), (off_t)0); - if( fseek(_fptr, _offset, SEEK_SET) ) { - _error = "Seek to offset:"; - _error += _offset; - _error += " failed."; - return -1; - } - assert(_offset == ftell(_fptr)); - return _offset; -} - -off_t Reader::tell() const -{ - if(!is_open()) - return -1; - return _offset; -} - -off_t Reader::size() const -{ - return _size; -} - -const char* Reader::lastError() const -{ - return _error.c_str(); -} -const char* Reader::filename() const -{ - return _filename.c_str(); -} - -// -// Protected member fn's -// - -bool Reader::loadPage(off_t pageIdx) -{ - if( !is_open() ) - return false; - if(_data[pageIdx] != 0) - return true; - - if( !nFreePages() ) { - // free the page which is the furthest away from the page we are loading - - // this could be trouble if off_t is unsigned! - if( abs(_firstPage - pageIdx) > abs(_lastPage - pageIdx) ) - while(!freePage(_firstPage++)); - else - while(!freePage(_lastPage--)); - } - _data[pageIdx] = new uchar [_pageSize]; - // page added, subtract from num available - --nFreePages(); - - fseek(_fptr,pageIdx*_pageSize, SEEK_SET); - - off_t retval = fread(_data[pageIdx], sizeof(uchar), _pageSize, _fptr); - - if( retval ) { - if( pageIdx < _firstPage ) - _firstPage = pageIdx; - - if( pageIdx > _lastPage ) - _lastPage = pageIdx; - } - return retval; -} - -bool Reader::freePage(off_t pageIdx) -{ - // check range - if( pageIdx < 0 || (unsigned)pageIdx >= _data.size() || !_data[pageIdx] ) - return false; - - delete [] _data[pageIdx]; - _data[pageIdx] = 0; - ++nFreePages(); // page freed - return true; -} - -uchar Reader::operator[] (off_t offset) -{ - if( !is_open() ) - throw logic_error("Reader::operator[] - attempt to access non-open file."); - if( offset < 0 ) - throw out_of_range("Reader::operator[] - " - "attempt to access negative offset."); - if( offset >= size() ) - throw out_of_range("Reader::operator[] - " - "attempt to access past end of file"); - - off_t page_idx = offset/_pageSize; - assert( loadPage( page_idx ) ); - return _data[page_idx][ offset%_pageSize ]; -} - -off_t -Reader::nFreePages() const -{ - return _freePages; -} - -off_t& -Reader::nFreePages() -{ - return _freePages; -} - -bool -Reader::dataIsAtOffset( const vector<uchar>& data, off_t pos ) -{ - size_t i = 0; - while( i < data.size() ) { - if( data[i] != (*this)[pos+i] ) { - return false; - } - ++i; - } - return true; -} - - -off_t -Reader::findIndex( off_t start, const vector<uchar>& data, off_t stop ) -{ - off_t pos = start; - while( pos <= stop ) { - if( data[0] == (*this)[pos] ) { - if( dataIsAtOffset( data, pos ) ) { - return pos; - } - } - ++pos; - } - return size(); -} - -off_t -Reader::rFindIndex( off_t start, const vector<uchar>& data, off_t stop ) -{ - off_t pos = start; - while( pos >= stop ) { - if( data[0] == (*this)[pos] ) { - if( dataIsAtOffset( data, pos ) ) { - return pos; - } - } - --pos; - } - return size(); -} - -// -// ReadBuffer friends and aquaintances (only for debugging) -// - -#if 0 -ostream& operator<< (ostream&out, const ReadBuffer& buff) -{ - ios_base::fmtflags old_flags = out.flags(); - out.flags(old_flags | ios::hex | ios::showbase); - for(size_t i = 0; i < buff.size(); i++) - out << buff[i]; - // restore old flags - out.flags(old_flags); - return out; -} -#endif |