1 files changed, 146 insertions, 0 deletions
diff --git a/src/lib/io/StreamBuffer.cpp b/src/lib/io/StreamBuffer.cpp
new file mode 100644
index 0000000..61f05ba
--- /dev/null
+++ b/src/lib/io/StreamBuffer.cpp
@@ -0,0 +1,146 @@
+/*
+ * barrier -- mouse and keyboard sharing utility
+ * Copyright (C) 2012-2016 Symless Ltd.
+ * Copyright (C) 2002 Chris Schoeneman
+ * 
+ * This package is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * found in the file LICENSE that should have accompanied this file.
+ * 
+ * This package 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "io/StreamBuffer.h"
+
+//
+// StreamBuffer
+//
+
+const UInt32            StreamBuffer::kChunkSize = 4096;
+
+StreamBuffer::StreamBuffer() :
+    m_size(0),
+    m_headUsed(0)
+{
+    // do nothing
+}
+
+StreamBuffer::~StreamBuffer()
+{
+    // do nothing
+}
+
+const void*
+StreamBuffer::peek(UInt32 n)
+{
+    assert(n <= m_size);
+
+    // if requesting no data then return NULL so we don't try to access
+    // an empty list.
+    if (n == 0) {
+        return NULL;
+    }
+
+    // reserve space in first chunk
+    ChunkList::iterator head = m_chunks.begin();
+    head->reserve(n + m_headUsed);
+
+    // consolidate chunks into the first chunk until it has n bytes
+    ChunkList::iterator scan = head;
+    ++scan;
+    while (head->size() - m_headUsed < n && scan != m_chunks.end()) {
+        head->insert(head->end(), scan->begin(), scan->end());
+        scan = m_chunks.erase(scan);
+    }
+
+    return static_cast<const void*>(&(head->begin()[m_headUsed]));
+}
+
+void
+StreamBuffer::pop(UInt32 n)
+{
+    // discard all chunks if n is greater than or equal to m_size
+    if (n >= m_size) {
+        m_size     = 0;
+        m_headUsed = 0;
+        m_chunks.clear();
+        return;
+    }
+
+    // update size
+    m_size -= n;
+
+    // discard chunks until more than n bytes would've been discarded
+    ChunkList::iterator scan = m_chunks.begin();
+    assert(scan != m_chunks.end());
+    while (scan->size() - m_headUsed <= n) {
+        n         -= (UInt32)scan->size() - m_headUsed;
+        m_headUsed = 0;
+        scan       = m_chunks.erase(scan);
+        assert(scan != m_chunks.end());
+    }
+
+    // remove left over bytes from the head chunk
+    if (n > 0) {
+        m_headUsed += n;
+    }
+}
+
+void
+StreamBuffer::write(const void* vdata, UInt32 n)
+{
+    assert(vdata != NULL);
+
+    // ignore if no data, otherwise update size
+    if (n == 0) {
+        return;
+    }
+    m_size += n;
+
+    // cast data to bytes
+    const UInt8* data = static_cast<const UInt8*>(vdata);
+
+    // point to last chunk if it has space, otherwise append an empty chunk
+    ChunkList::iterator scan = m_chunks.end();
+    if (scan != m_chunks.begin()) {
+        --scan;
+        if (scan->size() >= kChunkSize) {
+            ++scan;
+        }
+    }
+    if (scan == m_chunks.end()) {
+        scan = m_chunks.insert(scan, Chunk());
+    }
+
+    // append data in chunks
+    while (n > 0) {
+        // choose number of bytes for next chunk
+        assert(scan->size() <= kChunkSize);
+        UInt32 count = kChunkSize - (UInt32)scan->size();
+        if (count > n)
+            count = n;
+
+        // transfer data
+        scan->insert(scan->end(), data, data + count);
+        n    -= count;
+        data += count;
+
+        // append another empty chunk if we're not done yet
+        if (n > 0) {
+            ++scan;
+            scan = m_chunks.insert(scan, Chunk());
+        }
+    }
+}
+
+UInt32
+StreamBuffer::getSize() const
+{
+    return m_size;
+}