1//---------------------------------------------------------------------- 2// This software is part of the OpenBeOS distribution and is covered 3// by the OpenBeOS license. 4// 5// Copyright (c) 2003 Tyler Dauwalder, tyler@dauwalder.net 6//---------------------------------------------------------------------- 7 8/*! \file ExtentStream.cpp 9*/ 10 11#include "ExtentStream.h" 12 13#include <stdlib.h> 14#include <string.h> 15 16ExtentStream::ExtentStream(DataStream &stream, 17 const std::list<Udf::extent_address> &extentList, 18 uint32 blockSize) 19 : SimulatedStream(stream) 20 , fExtentList(extentList) 21 , fBlockSize(blockSize) 22 , fSize(0) 23{ 24 for (std::list<Udf::extent_address>::const_iterator i = fExtentList.begin(); 25 i != fExtentList.end(); 26 i++) 27 { 28 fSize += i->length(); 29 } 30} 31 32/*! \brief Returns the largest extent in the underlying data stream 33 corresponding to the extent starting at byte position \a pos of 34 byte length \a size in the output parameter \a extent. 35 36 NOTE: If the position is at or beyond the end of the stream, the 37 function will return B_OK, but the value of extent.size will be 0. 38*/ 39status_t 40ExtentStream::_GetExtent(off_t pos, size_t size, data_extent &extent) 41{ 42 status_t error = pos >= 0 ? B_OK : B_BAD_VALUE; 43 if (!error) { 44 off_t finalOffset = 0; 45 off_t streamPos = 0; 46 for (std::list<Udf::extent_address>::const_iterator i = fExtentList.begin(); 47 i != fExtentList.end(); 48 i++) 49 { 50 off_t offset = i->location() * fBlockSize; 51 finalOffset = offset + i->length(); 52 if (streamPos <= pos && pos < streamPos+i->length()) { 53 // Found it 54 off_t difference = pos - streamPos; 55 extent.offset = offset + difference; 56 extent.size = i->length() - difference; 57 if (extent.size > size) 58 extent.size = size; 59 return B_OK; 60 } else { 61 streamPos += i->length(); 62 } 63 } 64 // Didn't find it, so pos is past the end of the stream 65 extent.offset = finalOffset; 66 extent.size = 0; 67 } 68 return error; 69} 70 71/*! \brief Returns the current size of the stream. 72*/ 73off_t 74ExtentStream::_Size() 75{ 76 return fSize; 77} 78