1 files changed, 173 insertions, 0 deletions
diff --git a/io/source/stm/streamhelper.cxx b/io/source/stm/streamhelper.cxx
new file mode 100644
index 000000000..0933ac966
--- /dev/null
+++ b/io/source/stm/streamhelper.cxx
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <limits>
+#include <string.h>
+
+#include <com/sun/star/uno/Sequence.hxx>
+
+#include <com/sun/star/io/BufferSizeExceededException.hpp>
+
+using namespace ::com::sun::star::uno;
+
+#include "streamhelper.hxx"
+
+namespace io_stm {
+
+void MemFIFO::write( const Sequence< sal_Int8 > &seq )
+{
+    writeAt(getSize(), seq);
+}
+
+void MemFIFO::read( Sequence<sal_Int8> &seq , sal_Int32 nBufferLen )
+{
+    readAt(0, seq , nBufferLen);
+    forgetFromStart( nBufferLen );
+}
+
+void MemFIFO::skip( sal_Int32 nBytesToSkip )
+{
+    forgetFromStart( nBytesToSkip );
+}
+
+MemRingBuffer::MemRingBuffer() : m_p(nullptr), m_nBufferLen(0), m_nStart(0), m_nOccupiedBuffer(0)
+{
+}
+
+MemRingBuffer::~MemRingBuffer()
+{
+    std::free( m_p );
+}
+
+void MemRingBuffer::resizeBuffer( sal_Int32 nMinSize )
+{
+    sal_Int32 nNewLen = 1;
+
+    while( nMinSize > nNewLen ) {
+        nNewLen = nNewLen << 1;
+    }
+
+    // buffer never shrinks !
+    if( nNewLen < m_nBufferLen ) {
+        nNewLen = m_nBufferLen;
+    }
+
+    if( nNewLen == m_nBufferLen )
+        return;
+
+    auto p = static_cast<sal_Int8*>(std::realloc(m_p, nNewLen));
+    if (!p)
+        throw css::io::BufferSizeExceededException(
+            "MemRingBuffer::resizeBuffer BufferSizeExceededException");
+
+    m_p = p;
+
+
+    if( m_nStart + m_nOccupiedBuffer > m_nBufferLen ) {
+        memmove( &( m_p[m_nStart+(nNewLen-m_nBufferLen)]) , &(m_p[m_nStart]) , m_nBufferLen - m_nStart );
+        m_nStart += nNewLen - m_nBufferLen;
+    }
+    m_nBufferLen = nNewLen;
+}
+
+
+void MemRingBuffer::readAt( sal_Int32 nPos, Sequence<sal_Int8> &seq , sal_Int32 nBytesToRead ) const
+{
+    if( nPos + nBytesToRead > m_nOccupiedBuffer ) {
+        throw css::io::BufferSizeExceededException(
+            "MemRingBuffer::readAt BufferSizeExceededException");
+    }
+
+    sal_Int32 nStartReadingPos = nPos + m_nStart;
+    if( nStartReadingPos >= m_nBufferLen ) {
+        nStartReadingPos -= m_nBufferLen;
+    }
+
+    seq.realloc( nBytesToRead );
+
+    if( nStartReadingPos + nBytesToRead > m_nBufferLen ) {
+        sal_Int32 nDeltaLen = m_nBufferLen - nStartReadingPos;
+        memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nDeltaLen );
+        memcpy( &(seq.getArray()[nDeltaLen]), m_p , nBytesToRead - nDeltaLen );
+    }
+    else {
+        memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nBytesToRead );
+    }
+}
+
+
+void MemRingBuffer::writeAt( sal_Int32 nPos, const Sequence<sal_Int8> &seq )
+{
+    checkInvariants();
+    const sal_Int32 nLen = seq.getLength();
+
+    if( nPos < 0 || nPos > std::numeric_limits< sal_Int32 >::max() - nLen )
+    {
+        throw css::io::BufferSizeExceededException(
+            "MemRingBuffer::writeAt BufferSizeExceededException");
+    }
+
+    if( nPos + nLen - m_nOccupiedBuffer > 0 ) {
+        resizeBuffer( nPos + nLen );
+        m_nOccupiedBuffer = nPos + nLen;
+    }
+
+    sal_Int32 nStartWritingIndex = m_nStart + nPos;
+    if( nStartWritingIndex >= m_nBufferLen ) {
+        nStartWritingIndex -= m_nBufferLen;
+    }
+
+    if( const sal_Int32 nBufferRestLen = m_nBufferLen-nStartWritingIndex; nLen > nBufferRestLen ) {
+        // two area copy
+        memcpy( &(m_p[nStartWritingIndex]) , seq.getConstArray(), nBufferRestLen );
+        memcpy( m_p , &( seq.getConstArray()[nBufferRestLen] ), nLen - nBufferRestLen );
+
+    }
+    else {
+        // one area copy
+        memcpy( &( m_p[nStartWritingIndex]), seq.getConstArray() , nLen );
+    }
+    checkInvariants();
+}
+
+
+sal_Int32 MemRingBuffer::getSize()  const noexcept
+{
+    return m_nOccupiedBuffer;
+}
+
+void MemRingBuffer::forgetFromStart( sal_Int32 nBytesToForget )
+{
+    checkInvariants();
+    if( nBytesToForget > m_nOccupiedBuffer ) {
+        throw css::io::BufferSizeExceededException(
+            "MemRingBuffer::forgetFromStart BufferSizeExceededException");
+    }
+    m_nStart += nBytesToForget;
+    if( m_nStart >= m_nBufferLen ) {
+        m_nStart = m_nStart - m_nBufferLen;
+    }
+    m_nOccupiedBuffer -= nBytesToForget;
+    checkInvariants();
+}
+
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */