/indra/llmessage/llbufferstream.cpp
https://bitbucket.org/lindenlab/viewer-beta/ · C++ · 352 lines · 228 code · 23 blank · 101 comment · 41 complexity · b30836f76442528922091a36097a2703 MD5 · raw file
- /**
- * @file llbufferstream.cpp
- * @author Phoenix
- * @date 2005-10-10
- * @brief Implementation of the buffer iostream classes
- *
- * $LicenseInfo:firstyear=2005&license=viewerlgpl$
- * Second Life Viewer Source Code
- * Copyright (C) 2010, Linden Research, Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License only.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
- * $/LicenseInfo$
- */
- #include "linden_common.h"
- #include "llbufferstream.h"
- #include "llbuffer.h"
- #include "llmemtype.h"
- #include "llthread.h"
- static const S32 DEFAULT_OUTPUT_SEGMENT_SIZE = 1024 * 4;
- /*
- * LLBufferStreamBuf
- */
- LLBufferStreamBuf::LLBufferStreamBuf(
- const LLChannelDescriptors& channels,
- LLBufferArray* buffer) :
- mChannels(channels),
- mBuffer(buffer)
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- }
- LLBufferStreamBuf::~LLBufferStreamBuf()
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- sync();
- }
- // virtual
- int LLBufferStreamBuf::underflow()
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- //lldebugs << "LLBufferStreamBuf::underflow()" << llendl;
- if(!mBuffer)
- {
- return EOF;
- }
- LLMutexLock lock(mBuffer->getMutex());
- LLBufferArray::segment_iterator_t iter;
- LLBufferArray::segment_iterator_t end = mBuffer->endSegment();
- U8* last_pos = (U8*)gptr();
- LLSegment segment;
- if(last_pos)
- {
- // Back up into a piece of memory we know that we have
- // allocated so that calls for the next segment based on
- // 'after' will succeed.
- --last_pos;
- iter = mBuffer->splitAfter(last_pos);
- if(iter != end)
- {
- // We need to clear the read segment just in case we have
- // an early exit in the function and never collect the
- // next segment. Calling eraseSegment() with the same
- // segment twice is just like double deleting -- nothing
- // good comes from it.
- mBuffer->eraseSegment(iter++);
- if(iter != end) segment = (*iter);
- }
- else
- {
- // This should never really happen, but somehow, the
- // istream is telling the buf that it just finished
- // reading memory that is not in the buf. I think this
- // would only happen if there were a bug in the c++ stream
- // class. Just bail.
- // *TODO: can we set the fail bit on the stream somehow?
- return EOF;
- }
- }
- else
- {
- // Get iterator to full segment containing last_pos
- // and construct sub-segment starting at last_pos.
- // Note: segment may != *it at this point
- iter = mBuffer->constructSegmentAfter(last_pos, segment);
- }
- if(iter == end)
- {
- return EOF;
- }
- // Iterate through segments to find a non-empty segment on input channel.
- while((!segment.isOnChannel(mChannels.in()) || (segment.size() == 0)))
- {
- ++iter;
- if(iter == end)
- {
- return EOF;
- }
- segment = *(iter);
- }
- // set up the stream to read from the next segment.
- char* start = (char*)segment.data();
- setg(start, start, start + segment.size());
- return *gptr();
- }
- // virtual
- int LLBufferStreamBuf::overflow(int c)
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- if(!mBuffer)
- {
- return EOF;
- }
- if(EOF == c)
- {
- // if someone puts an EOF, I suppose we should sync and return
- // success.
- if(0 == sync())
- {
- return 1;
- }
- else
- {
- return EOF;
- }
- }
- // since we got here, we have a buffer, and we have a character to
- // put on it.
- LLBufferArray::segment_iterator_t it;
- LLMutexLock lock(mBuffer->getMutex());
- it = mBuffer->makeSegment(mChannels.out(), DEFAULT_OUTPUT_SEGMENT_SIZE);
- if(it != mBuffer->endSegment())
- {
- char* start = (char*)(*it).data();
- (*start) = (char)(c);
- setp(start + 1, start + (*it).size());
- return c;
- }
- else
- {
- return EOF;
- }
- }
- // virtual
- int LLBufferStreamBuf::sync()
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- int return_value = -1;
- if(!mBuffer)
- {
- return return_value;
- }
- // This chunk of code is not necessary because typically, users of
- // the stream will read until EOF. Therefore, underflow was called
- // and the segment was discarded before the sync() was called in
- // the destructor. Theoretically, we could keep some more data
- // around and detect the rare case where an istream was deleted
- // before reading to the end, but that will only leave behind some
- // unavailable but still referenced memory. Also, if another
- // istream is constructed, it will re-read that segment, and then
- // discard it.
- //U8* last_pos = (U8*)gptr();
- //if(last_pos)
- //{
- // // Looks like we read something. Discard what we have read.
- // // gptr() actually returns the currrent position, but we call
- // // it last_pos because of how it is used in the split call
- // // below.
- // --last_pos;
- // LLBufferArray::segment_iterator_t iter;
- // iter = mBuffer->splitAfter(last_pos);
- // if(iter != mBuffer->endSegment())
- // {
- // // We need to clear the read segment just in case we have
- // // an early exit in the function and never collect the
- // // next segment. Calling eraseSegment() with the same
- // // segment twice is just like double deleting -- nothing
- // // good comes from it.
- // mBuffer->eraseSegment(iter);
- // }
- //}
- // set the put pointer so that we force an overflow on the next
- // write.
- U8* address = (U8*)pptr();
- setp(NULL, NULL);
- // *NOTE: I bet we could just --address if address is not NULL.
- // Need to think about that.
- LLMutexLock lock(mBuffer->getMutex());
- address = mBuffer->seek(mChannels.out(), address, -1);
- if(address)
- {
- LLBufferArray::segment_iterator_t it;
- it = mBuffer->splitAfter(address);
- LLBufferArray::segment_iterator_t end = mBuffer->endSegment();
- if(it != end)
- {
- ++it;
- if(it != end)
- {
- mBuffer->eraseSegment(it);
- }
- return_value = 0;
- }
- }
- else
- {
- // nothing was put on the buffer, so the sync() is a no-op.
- return_value = 0;
- }
- return return_value;
- }
- // virtual
- #if( LL_WINDOWS || __GNUC__ > 2)
- LLBufferStreamBuf::pos_type LLBufferStreamBuf::seekoff(
- LLBufferStreamBuf::off_type off,
- std::ios::seekdir way,
- std::ios::openmode which)
- #else
- streampos LLBufferStreamBuf::seekoff(
- streamoff off,
- std::ios::seekdir way,
- std::ios::openmode which)
- #endif
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- if(!mBuffer
- || ((way == std::ios::beg) && (off < 0))
- || ((way == std::ios::end) && (off > 0)))
- {
- return -1;
- }
- U8* address = NULL;
- if(which & std::ios::in)
- {
- U8* base_addr = NULL;
- switch(way)
- {
- case std::ios::end:
- base_addr = (U8*)LLBufferArray::npos;
- break;
- case std::ios::cur:
- // get the current get pointer and adjust it for buffer
- // array semantics.
- base_addr = (U8*)gptr();
- break;
- case std::ios::beg:
- default:
- // NULL is fine
- break;
- }
- LLMutexLock lock(mBuffer->getMutex());
- address = mBuffer->seek(mChannels.in(), base_addr, off);
- if(address)
- {
- LLBufferArray::segment_iterator_t iter;
- iter = mBuffer->getSegment(address);
- char* start = (char*)(*iter).data();
- setg(start, (char*)address, start + (*iter).size());
- }
- else
- {
- address = (U8*)(-1);
- }
- }
- if(which & std::ios::out)
- {
- U8* base_addr = NULL;
- switch(way)
- {
- case std::ios::end:
- base_addr = (U8*)LLBufferArray::npos;
- break;
- case std::ios::cur:
- // get the current put pointer and adjust it for buffer
- // array semantics.
- base_addr = (U8*)pptr();
- break;
- case std::ios::beg:
- default:
- // NULL is fine
- break;
- }
- LLMutexLock lock(mBuffer->getMutex());
- address = mBuffer->seek(mChannels.out(), base_addr, off);
- if(address)
- {
- LLBufferArray::segment_iterator_t iter;
- iter = mBuffer->getSegment(address);
- setp((char*)address, (char*)(*iter).data() + (*iter).size());
- }
- else
- {
- address = (U8*)(-1);
- }
- }
- #if( LL_WINDOWS || __GNUC__ > 2 )
- S32 rv = (S32)(intptr_t)address;
- return (pos_type)rv;
- #else
- return (streampos)address;
- #endif
- }
- /*
- * LLBufferStream
- */
- LLBufferStream::LLBufferStream(
- const LLChannelDescriptors& channels,
- LLBufferArray* buffer) :
- std::iostream(&mStreamBuf),
- mStreamBuf(channels, buffer)
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- }
- LLBufferStream::~LLBufferStream()
- {
- LLMemType m1(LLMemType::MTYPE_IO_BUFFER);
- }