nuclear@1: /**************************************************************************
nuclear@1: 
nuclear@1: Filename    :   OVR_File.cpp
nuclear@1: Content     :   File wrapper class implementation (Win32)
nuclear@1: 
nuclear@1: Created     :   April 5, 1999
nuclear@1: Authors     :   Michael Antonov
nuclear@1: 
nuclear@1: Copyright   :   Copyright 2012 Oculus VR, Inc. All Rights reserved.
nuclear@1: 
nuclear@1: Use of this software is subject to the terms of the Oculus license
nuclear@1: agreement provided at the time of installation or download, or which
nuclear@1: otherwise accompanies this software in either electronic or hard copy form.
nuclear@1: 
nuclear@1: **************************************************************************/
nuclear@1: 
nuclear@1: #define  GFILE_CXX
nuclear@1: 
nuclear@1: // Standard C library (Captain Obvious guarantees!)
nuclear@1: #include <stdio.h>
nuclear@1: 
nuclear@1: #include "OVR_File.h"
nuclear@1: 
nuclear@1: namespace OVR {
nuclear@1: 
nuclear@1: // Buffered file adds buffering to an existing file
nuclear@1: // FILEBUFFER_SIZE defines the size of internal buffer, while
nuclear@1: // FILEBUFFER_TOLERANCE controls the amount of data we'll effectively try to buffer
nuclear@1: #define FILEBUFFER_SIZE         (8192-8)
nuclear@1: #define FILEBUFFER_TOLERANCE    4096
nuclear@1: 
nuclear@1: // ** Constructor/Destructor
nuclear@1: 
nuclear@1: // Hidden constructor
nuclear@1: // Not supposed to be used
nuclear@1: BufferedFile::BufferedFile() : DelegatedFile(0)
nuclear@1: {
nuclear@1:     pBuffer     = (UByte*)OVR_ALLOC(FILEBUFFER_SIZE);
nuclear@1:     BufferMode  = NoBuffer;
nuclear@1:     FilePos     = 0;
nuclear@1:     Pos         = 0;
nuclear@1:     DataSize    = 0;
nuclear@1: }
nuclear@1: 
nuclear@1: // Takes another file as source
nuclear@1: BufferedFile::BufferedFile(File *pfile) : DelegatedFile(pfile)
nuclear@1: {
nuclear@1:     pBuffer     = (UByte*)OVR_ALLOC(FILEBUFFER_SIZE);
nuclear@1:     BufferMode  = NoBuffer;
nuclear@1:     FilePos     = pfile->LTell();
nuclear@1:     Pos         = 0;
nuclear@1:     DataSize    = 0;
nuclear@1: }
nuclear@1: 
nuclear@1: 
nuclear@1: // Destructor
nuclear@1: BufferedFile::~BufferedFile()
nuclear@1: {
nuclear@1:     // Flush in case there's data
nuclear@1:     if (pFile)
nuclear@1:         FlushBuffer();
nuclear@1:     // Get rid of buffer
nuclear@1:     if (pBuffer)
nuclear@1:         OVR_FREE(pBuffer);
nuclear@1: }
nuclear@1: 
nuclear@1: /*
nuclear@1: bool    BufferedFile::VCopy(const Object &source)
nuclear@1: {
nuclear@1:     if (!DelegatedFile::VCopy(source))
nuclear@1:         return 0;
nuclear@1: 
nuclear@1:     // Data members
nuclear@1:     BufferedFile *psource = (BufferedFile*)&source;
nuclear@1: 
nuclear@1:     // Buffer & the mode it's in
nuclear@1:     pBuffer         = psource->pBuffer;
nuclear@1:     BufferMode      = psource->BufferMode;
nuclear@1:     Pos             = psource->Pos;
nuclear@1:     DataSize        = psource->DataSize;
nuclear@1:     return 1;
nuclear@1: }
nuclear@1: */
nuclear@1: 
nuclear@1: // Initializes buffering to a certain mode
nuclear@1: bool    BufferedFile::SetBufferMode(BufferModeType mode)
nuclear@1: {
nuclear@1:     if (!pBuffer)
nuclear@1:         return false;
nuclear@1:     if (mode == BufferMode)
nuclear@1:         return true;
nuclear@1:      
nuclear@1:     FlushBuffer();
nuclear@1: 
nuclear@1:     // Can't set write mode if we can't write
nuclear@1:     if ((mode==WriteBuffer) && (!pFile || !pFile->IsWritable()) )
nuclear@1:         return 0;
nuclear@1: 
nuclear@1:     // And SetMode
nuclear@1:     BufferMode = mode;
nuclear@1:     Pos        = 0;
nuclear@1:     DataSize   = 0;
nuclear@1:     return 1;
nuclear@1: }
nuclear@1: 
nuclear@1: // Flushes buffer
nuclear@1: void    BufferedFile::FlushBuffer()
nuclear@1: {
nuclear@1:     switch(BufferMode)
nuclear@1:     {
nuclear@1:         case WriteBuffer:
nuclear@1:             // Write data in buffer
nuclear@1:             FilePos += pFile->Write(pBuffer,Pos);
nuclear@1:             Pos = 0;
nuclear@1:             break;
nuclear@1: 
nuclear@1:         case ReadBuffer:
nuclear@1:             // Seek back & reset buffer data
nuclear@1:             if ((DataSize-Pos)>0)
nuclear@1:                 FilePos = pFile->LSeek(-(int)(DataSize-Pos), Seek_Cur);
nuclear@1:             DataSize = 0;
nuclear@1:             Pos      = 0;
nuclear@1:             break;
nuclear@1:         default:
nuclear@1:             // not handled!
nuclear@1:             break;
nuclear@1:     }
nuclear@1: }
nuclear@1: 
nuclear@1: // Reloads data for ReadBuffer
nuclear@1: void    BufferedFile::LoadBuffer()
nuclear@1: {
nuclear@1:     if (BufferMode == ReadBuffer)
nuclear@1:     {
nuclear@1:         // We should only reload once all of pre-loaded buffer is consumed.
nuclear@1:         OVR_ASSERT(Pos == DataSize);
nuclear@1: 
nuclear@1:         // WARNING: Right now LoadBuffer() assumes the buffer's empty
nuclear@1:         int sz   = pFile->Read(pBuffer,FILEBUFFER_SIZE);
nuclear@1:         DataSize = sz<0 ? 0 : (unsigned)sz;
nuclear@1:         Pos      = 0;
nuclear@1:         FilePos  += DataSize;
nuclear@1:     }
nuclear@1: }
nuclear@1: 
nuclear@1: 
nuclear@1: // ** Overridden functions
nuclear@1: 
nuclear@1: // We override all the functions that can possibly
nuclear@1: // require buffer mode switch, flush, or extra calculations
nuclear@1: 
nuclear@1: // Tell() requires buffer adjustment
nuclear@1: int     BufferedFile::Tell()
nuclear@1: {
nuclear@1:     if (BufferMode == ReadBuffer)
nuclear@1:         return int (FilePos - DataSize + Pos);
nuclear@1: 
nuclear@1:     int pos = pFile->Tell();
nuclear@1:     // Adjust position based on buffer mode & data
nuclear@1:     if (pos!=-1)
nuclear@1:     {
nuclear@1:         OVR_ASSERT(BufferMode != ReadBuffer);
nuclear@1:         if (BufferMode == WriteBuffer)
nuclear@1:             pos += Pos;
nuclear@1:     }
nuclear@1:     return pos;
nuclear@1: }
nuclear@1: 
nuclear@1: SInt64  BufferedFile::LTell()
nuclear@1: {
nuclear@1:     if (BufferMode == ReadBuffer)
nuclear@1:         return FilePos - DataSize + Pos;
nuclear@1: 
nuclear@1:     SInt64 pos = pFile->LTell();
nuclear@1:     if (pos!=-1)
nuclear@1:     {
nuclear@1:         OVR_ASSERT(BufferMode != ReadBuffer);
nuclear@1:         if (BufferMode == WriteBuffer)
nuclear@1:             pos += Pos;
nuclear@1:     }
nuclear@1:     return pos;
nuclear@1: }
nuclear@1: 
nuclear@1: int     BufferedFile::GetLength()
nuclear@1: {
nuclear@1:     int len = pFile->GetLength();
nuclear@1:     // If writing through buffer, file length may actually be bigger
nuclear@1:     if ((len!=-1) && (BufferMode==WriteBuffer))
nuclear@1:     {
nuclear@1:         int currPos = pFile->Tell() + Pos;
nuclear@1:         if (currPos>len)
nuclear@1:             len = currPos;
nuclear@1:     }
nuclear@1:     return len;
nuclear@1: }
nuclear@1: SInt64  BufferedFile::LGetLength()
nuclear@1: {
nuclear@1:     SInt64 len = pFile->LGetLength();
nuclear@1:     // If writing through buffer, file length may actually be bigger
nuclear@1:     if ((len!=-1) && (BufferMode==WriteBuffer))
nuclear@1:     {
nuclear@1:         SInt64 currPos = pFile->LTell() + Pos;
nuclear@1:         if (currPos>len)
nuclear@1:             len = currPos;
nuclear@1:     }
nuclear@1:     return len;
nuclear@1: }
nuclear@1: 
nuclear@1: /*
nuclear@1: bool    BufferedFile::Stat(FileStats *pfs)
nuclear@1: {
nuclear@1:     // Have to fix up length is stat
nuclear@1:     if (pFile->Stat(pfs))
nuclear@1:     {
nuclear@1:         if (BufferMode==WriteBuffer)
nuclear@1:         {
nuclear@1:             SInt64 currPos = pFile->LTell() + Pos;
nuclear@1:             if (currPos > pfs->Size)
nuclear@1:             {
nuclear@1:                 pfs->Size   = currPos;
nuclear@1:                 // ??
nuclear@1:                 pfs->Blocks = (pfs->Size+511) >> 9;
nuclear@1:             }
nuclear@1:         }
nuclear@1:         return 1;
nuclear@1:     }
nuclear@1:     return 0;
nuclear@1: }
nuclear@1: */
nuclear@1: 
nuclear@1: int     BufferedFile::Write(const UByte *psourceBuffer, int numBytes)
nuclear@1: {
nuclear@1:     if ( (BufferMode==WriteBuffer) || SetBufferMode(WriteBuffer))
nuclear@1:     {
nuclear@1:         // If not data space in buffer, flush
nuclear@1:         if ((FILEBUFFER_SIZE-(int)Pos)<numBytes)
nuclear@1:         {
nuclear@1:             FlushBuffer();
nuclear@1:             // If bigger then tolerance, just write directly
nuclear@1:             if (numBytes>FILEBUFFER_TOLERANCE)
nuclear@1:             {
nuclear@1:                 int sz = pFile->Write(psourceBuffer,numBytes);
nuclear@1:                 if (sz > 0)
nuclear@1:                     FilePos += sz;
nuclear@1:                 return sz;
nuclear@1:             }
nuclear@1:         }
nuclear@1: 
nuclear@1:         // Enough space in buffer.. so copy to it
nuclear@1:         memcpy(pBuffer+Pos, psourceBuffer, numBytes);
nuclear@1:         Pos += numBytes;
nuclear@1:         return numBytes;
nuclear@1:     }
nuclear@1:     int sz = pFile->Write(psourceBuffer,numBytes);
nuclear@1:     if (sz > 0)
nuclear@1:         FilePos += sz;
nuclear@1:     return sz;
nuclear@1: }
nuclear@1: 
nuclear@1: int     BufferedFile::Read(UByte *pdestBuffer, int numBytes)
nuclear@1: {
nuclear@1:     if ( (BufferMode==ReadBuffer) || SetBufferMode(ReadBuffer))
nuclear@1:     {
nuclear@1:         // Data in buffer... copy it
nuclear@1:         if ((int)(DataSize-Pos) >= numBytes)
nuclear@1:         {
nuclear@1:             memcpy(pdestBuffer, pBuffer+Pos, numBytes);
nuclear@1:             Pos += numBytes;
nuclear@1:             return numBytes;
nuclear@1:         }
nuclear@1: 
nuclear@1:         // Not enough data in buffer, copy buffer
nuclear@1:         int     readBytes = DataSize-Pos;
nuclear@1:         memcpy(pdestBuffer, pBuffer+Pos, readBytes);
nuclear@1:         numBytes    -= readBytes;
nuclear@1:         pdestBuffer += readBytes;
nuclear@1:         Pos = DataSize;
nuclear@1: 
nuclear@1:         // Don't reload buffer if more then tolerance
nuclear@1:         // (No major advantage, and we don't want to write a loop)
nuclear@1:         if (numBytes>FILEBUFFER_TOLERANCE)
nuclear@1:         {
nuclear@1:             numBytes = pFile->Read(pdestBuffer,numBytes);
nuclear@1:             if (numBytes > 0)
nuclear@1:             {
nuclear@1:                 FilePos += numBytes;
nuclear@1:                 Pos = DataSize = 0;
nuclear@1:             }
nuclear@1:             return readBytes + ((numBytes==-1) ? 0 : numBytes);
nuclear@1:         }
nuclear@1: 
nuclear@1:         // Reload the buffer
nuclear@1:         // WARNING: Right now LoadBuffer() assumes the buffer's empty
nuclear@1:         LoadBuffer();
nuclear@1:         if ((int)(DataSize-Pos) < numBytes)
nuclear@1:             numBytes = (int)DataSize-Pos;
nuclear@1: 
nuclear@1:         memcpy(pdestBuffer, pBuffer+Pos, numBytes);
nuclear@1:         Pos += numBytes;
nuclear@1:         return numBytes + readBytes;
nuclear@1:         
nuclear@1:         /*
nuclear@1:         // Alternative Read implementation. The one above is probably better
nuclear@1:         // due to FILEBUFFER_TOLERANCE.
nuclear@1:         int     total = 0;
nuclear@1: 
nuclear@1:         do {
nuclear@1:             int     bufferBytes = (int)(DataSize-Pos);
nuclear@1:             int     copyBytes = (bufferBytes > numBytes) ? numBytes : bufferBytes;
nuclear@1: 
nuclear@1:             memcpy(pdestBuffer, pBuffer+Pos, copyBytes);
nuclear@1:             numBytes    -= copyBytes;
nuclear@1:             pdestBuffer += copyBytes;
nuclear@1:             Pos         += copyBytes;
nuclear@1:             total       += copyBytes;
nuclear@1: 
nuclear@1:             if (numBytes == 0)
nuclear@1:                 break;
nuclear@1:             LoadBuffer();
nuclear@1: 
nuclear@1:         } while (DataSize > 0);
nuclear@1: 
nuclear@1:         return total;
nuclear@1:         */     
nuclear@1:     }
nuclear@1:     int sz = pFile->Read(pdestBuffer,numBytes);
nuclear@1:     if (sz > 0)
nuclear@1:         FilePos += sz;
nuclear@1:     return sz;
nuclear@1: }
nuclear@1: 
nuclear@1: 
nuclear@1: int     BufferedFile::SkipBytes(int numBytes)
nuclear@1: {
nuclear@1:     int skippedBytes = 0;
nuclear@1: 
nuclear@1:     // Special case for skipping a little data in read buffer
nuclear@1:     if (BufferMode==ReadBuffer)
nuclear@1:     {
nuclear@1:         skippedBytes = (((int)DataSize-(int)Pos) >= numBytes) ? numBytes : (DataSize-Pos);
nuclear@1:         Pos          += skippedBytes;
nuclear@1:         numBytes     -= skippedBytes;
nuclear@1:     }
nuclear@1: 
nuclear@1:     if (numBytes)
nuclear@1:     {
nuclear@1:         numBytes = pFile->SkipBytes(numBytes);
nuclear@1:         // Make sure we return the actual number skipped, or error
nuclear@1:         if (numBytes!=-1)
nuclear@1:         {
nuclear@1:             skippedBytes += numBytes;
nuclear@1:             FilePos += numBytes;
nuclear@1:             Pos = DataSize = 0;
nuclear@1:         }
nuclear@1:         else if (skippedBytes <= 0)
nuclear@1:             skippedBytes = -1;
nuclear@1:     }
nuclear@1:     return skippedBytes;
nuclear@1: }
nuclear@1: 
nuclear@1: int     BufferedFile::BytesAvailable()
nuclear@1: {
nuclear@1:     int available = pFile->BytesAvailable();
nuclear@1:     // Adjust available size based on buffers
nuclear@1:     switch(BufferMode)
nuclear@1:     {
nuclear@1:         case ReadBuffer:
nuclear@1:             available += DataSize-Pos;
nuclear@1:             break;
nuclear@1:         case WriteBuffer:
nuclear@1:             available -= Pos;
nuclear@1:             if (available<0)
nuclear@1:                 available= 0;
nuclear@1:             break;
nuclear@1:         default:
nuclear@1:             break;
nuclear@1:     }
nuclear@1:     return available;
nuclear@1: }
nuclear@1: 
nuclear@1: bool    BufferedFile::Flush()
nuclear@1: {
nuclear@1:     FlushBuffer();
nuclear@1:     return pFile->Flush();
nuclear@1: }
nuclear@1: 
nuclear@1: // Seeking could be optimized better..
nuclear@1: int     BufferedFile::Seek(int offset, int origin)
nuclear@1: {    
nuclear@1:     if (BufferMode == ReadBuffer)
nuclear@1:     {
nuclear@1:         if (origin == Seek_Cur)
nuclear@1:         {
nuclear@1:             // Seek can fall either before or after Pos in the buffer,
nuclear@1:             // but it must be within bounds.
nuclear@1:             if (((unsigned(offset) + Pos)) <= DataSize)
nuclear@1:             {
nuclear@1:                 Pos += offset;
nuclear@1:                 return int (FilePos - DataSize + Pos);
nuclear@1:             }
nuclear@1: 
nuclear@1:             // Lightweight buffer "Flush". We do this to avoid an extra seek
nuclear@1:             // back operation which would take place if we called FlushBuffer directly.
nuclear@1:             origin = Seek_Set;
nuclear@1:             OVR_ASSERT(((FilePos - DataSize + Pos) + (UInt64)offset) < ~(UInt64)0);
nuclear@1:             offset = (int)(FilePos - DataSize + Pos) + offset;
nuclear@1:             Pos = DataSize = 0;
nuclear@1:         }
nuclear@1:         else if (origin == Seek_Set)
nuclear@1:         {
nuclear@1:             if (((unsigned)offset - (FilePos-DataSize)) <= DataSize)
nuclear@1:             {
nuclear@1:                 OVR_ASSERT((FilePos-DataSize) < ~(UInt64)0);
nuclear@1:                 Pos = (unsigned)offset - (unsigned)(FilePos-DataSize);
nuclear@1:                 return offset;
nuclear@1:             }
nuclear@1:             Pos = DataSize = 0;
nuclear@1:         }
nuclear@1:         else
nuclear@1:         {
nuclear@1:             FlushBuffer();
nuclear@1:         }
nuclear@1:     }
nuclear@1:     else
nuclear@1:     {
nuclear@1:         FlushBuffer();
nuclear@1:     }    
nuclear@1: 
nuclear@1:     /*
nuclear@1:     // Old Seek Logic
nuclear@1:     if (origin == Seek_Cur && offset + Pos < DataSize)
nuclear@1:     {
nuclear@1:         //OVR_ASSERT((FilePos - DataSize) >= (FilePos - DataSize + Pos + offset));
nuclear@1:         Pos += offset;
nuclear@1:         OVR_ASSERT(int (Pos) >= 0);
nuclear@1:         return int (FilePos - DataSize + Pos);
nuclear@1:     }
nuclear@1:     else if (origin == Seek_Set && unsigned(offset) >= FilePos - DataSize && unsigned(offset) < FilePos)
nuclear@1:     {
nuclear@1:         Pos = unsigned(offset - FilePos + DataSize);
nuclear@1:         OVR_ASSERT(int (Pos) >= 0);
nuclear@1:         return int (FilePos - DataSize + Pos);
nuclear@1:     }   
nuclear@1:     
nuclear@1:     FlushBuffer();
nuclear@1:     */
nuclear@1: 
nuclear@1: 
nuclear@1:     FilePos = pFile->Seek(offset,origin);
nuclear@1:     return int (FilePos);
nuclear@1: }
nuclear@1: 
nuclear@1: SInt64  BufferedFile::LSeek(SInt64 offset, int origin)
nuclear@1: {
nuclear@1:     if (BufferMode == ReadBuffer)
nuclear@1:     {
nuclear@1:         if (origin == Seek_Cur)
nuclear@1:         {
nuclear@1:             // Seek can fall either before or after Pos in the buffer,
nuclear@1:             // but it must be within bounds.
nuclear@1:             if (((unsigned(offset) + Pos)) <= DataSize)
nuclear@1:             {
nuclear@1:                 Pos += (unsigned)offset;
nuclear@1:                 return SInt64(FilePos - DataSize + Pos);
nuclear@1:             }
nuclear@1: 
nuclear@1:             // Lightweight buffer "Flush". We do this to avoid an extra seek
nuclear@1:             // back operation which would take place if we called FlushBuffer directly.
nuclear@1:             origin = Seek_Set;            
nuclear@1:             offset = (SInt64)(FilePos - DataSize + Pos) + offset;
nuclear@1:             Pos = DataSize = 0;
nuclear@1:         }
nuclear@1:         else if (origin == Seek_Set)
nuclear@1:         {
nuclear@1:             if (((UInt64)offset - (FilePos-DataSize)) <= DataSize)
nuclear@1:             {                
nuclear@1:                 Pos = (unsigned)((UInt64)offset - (FilePos-DataSize));
nuclear@1:                 return offset;
nuclear@1:             }
nuclear@1:             Pos = DataSize = 0;
nuclear@1:         }
nuclear@1:         else
nuclear@1:         {
nuclear@1:             FlushBuffer();
nuclear@1:         }
nuclear@1:     }
nuclear@1:     else
nuclear@1:     {
nuclear@1:         FlushBuffer();
nuclear@1:     }
nuclear@1: 
nuclear@1: /*
nuclear@1:     OVR_ASSERT(BufferMode != NoBuffer);
nuclear@1: 
nuclear@1:     if (origin == Seek_Cur && offset + Pos < DataSize)
nuclear@1:     {
nuclear@1:         Pos += int (offset);
nuclear@1:         return FilePos - DataSize + Pos;
nuclear@1:     }
nuclear@1:     else if (origin == Seek_Set && offset >= SInt64(FilePos - DataSize) && offset < SInt64(FilePos))
nuclear@1:     {
nuclear@1:         Pos = unsigned(offset - FilePos + DataSize);
nuclear@1:         return FilePos - DataSize + Pos;
nuclear@1:     }
nuclear@1: 
nuclear@1:     FlushBuffer();
nuclear@1:     */
nuclear@1: 
nuclear@1:     FilePos = pFile->LSeek(offset,origin);
nuclear@1:     return FilePos;
nuclear@1: }
nuclear@1: 
nuclear@1: int     BufferedFile::CopyFromStream(File *pstream, int byteSize)
nuclear@1: {
nuclear@1:     // We can't rely on overridden Write()
nuclear@1:     // because delegation doesn't override virtual pointers
nuclear@1:     // So, just re-implement
nuclear@1:     UByte   buff[0x4000];
nuclear@1:     int     count = 0;
nuclear@1:     int     szRequest, szRead, szWritten;
nuclear@1: 
nuclear@1:     while(byteSize)
nuclear@1:     {
nuclear@1:         szRequest = (byteSize > int(sizeof(buff))) ? int(sizeof(buff)) : byteSize;
nuclear@1: 
nuclear@1:         szRead    = pstream->Read(buff,szRequest);
nuclear@1:         szWritten = 0;
nuclear@1:         if (szRead > 0)
nuclear@1:             szWritten = Write(buff,szRead);
nuclear@1: 
nuclear@1:         count   +=szWritten;
nuclear@1:         byteSize-=szWritten;
nuclear@1:         if (szWritten < szRequest)
nuclear@1:             break;
nuclear@1:     }
nuclear@1:     return count;
nuclear@1: }
nuclear@1: 
nuclear@1: // Closing files
nuclear@1: bool    BufferedFile::Close()
nuclear@1: {
nuclear@1:     switch(BufferMode)
nuclear@1:     {
nuclear@1:         case WriteBuffer:
nuclear@1:             FlushBuffer();
nuclear@1:             break;
nuclear@1:         case ReadBuffer:
nuclear@1:             // No need to seek back on close
nuclear@1:             BufferMode = NoBuffer;
nuclear@1:             break;
nuclear@1:         default:
nuclear@1:             break;
nuclear@1:     }
nuclear@1:     return pFile->Close();
nuclear@1: }
nuclear@1: 
nuclear@1: 
nuclear@1: // ***** Global path helpers
nuclear@1: 
nuclear@1: // Find trailing short filename in a path.
nuclear@1: const char* OVR_CDECL GetShortFilename(const char* purl)
nuclear@1: {    
nuclear@1:     UPInt len = OVR_strlen(purl);
nuclear@1:     for (UPInt i=len; i>0; i--) 
nuclear@1:         if (purl[i]=='\\' || purl[i]=='/')
nuclear@1:             return purl+i+1;
nuclear@1:     return purl;
nuclear@1: }
nuclear@1: 
nuclear@1: } // OVR
nuclear@1: