kolibrios/programs/other/graph_tablelib/KosFile.cpp

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#include "kosSyst.h"
#include "kosfile.h"
//#include "string.h"
CKosFile::CKosFile(char *fileName)
{
//
this->fileInfo.bufferPtr = new Byte[FILE_BUFFER_SIZE];
//
this->filePointer = 0;
this->bufferPointer = 0;
this->validBuffer = false;
//
strcpy( this->fileInfo.fileURL, fileName );
}
CKosFile::~CKosFile(void)
{
//
delete this->fileInfo.bufferPtr;
}
void CKosFile::ValidateBuffer()
{
//
if ( this->validBuffer )
{
//
if ( this->filePointer < this->bufferPointer
|| this->filePointer >= (this->bufferPointer + FILE_BUFFER_SIZE) )
{
//
this->validBuffer = false;
}
}
}
void CKosFile::UpdateBuffer(void)
{
//
if ( ! this->validBuffer )
{
//
this->fileInfo.OffsetLow = this->filePointer / OS_BLOCK_SIZE;
this->fileInfo.OffsetHigh = 0;
//
this->bufferPointer = this->fileInfo.OffsetLow * OS_BLOCK_SIZE;
//
this->fileInfo.dataCount = FILE_BUFFER_BLOCKS;
//
this->fileInfo.rwMode = 0;
//
Dword rr = kos_FileSystemAccess( &(this->fileInfo) );
this->validBuffer = ( rr == 0 );
}
}
int CKosFile::Seek(int seekFrom, int seekStep)
{
//
switch ( seekFrom )
{
//
case SEEK_SET:
//
this->filePointer = seekStep;
break;
//
case SEEK_CUR:
//
this->filePointer += seekStep;
break;
}
//
this->ValidateBuffer();
//
return this->filePointer;
}
int CKosFile::Read(Byte *targetPtr, int readCount)
{
int bufferLeast, result;
//
result = 0;
//
do
{
//
this->UpdateBuffer();
//
if ( ! this->validBuffer ) return result;
//
bufferLeast = FILE_BUFFER_SIZE - (this->filePointer - this->bufferPointer);
//
if ( bufferLeast > readCount ) bufferLeast = readCount;
//
if ( bufferLeast )
{
//
memcpy(
targetPtr,
this->fileInfo.bufferPtr + (this->filePointer - this->bufferPointer),
bufferLeast
);
//
targetPtr += bufferLeast;
readCount -= bufferLeast;
this->filePointer += bufferLeast;
//
result += bufferLeast;
}
//
this->ValidateBuffer();
}
while ( readCount > 0 );
//
return result;
}
int CKosFile::Write(Byte *sourcePtr, int writeCount)
{
return 0;
}