1 files changed, 281 insertions, 0 deletions
diff --git a/indra/llcorehttp/bufferarray.cpp b/indra/llcorehttp/bufferarray.cpp
new file mode 100644
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+++ b/indra/llcorehttp/bufferarray.cpp
@@ -0,0 +1,281 @@
+/**
+ * @file bufferarray.cpp
+ * @brief Implements the BufferArray scatter/gather buffer
+ *
+ * $LicenseInfo:firstyear=2012&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2012, 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 "bufferarray.h"
+
+
+namespace LLCore
+{
+
+
+// ==================================
+// BufferArray::Block Declaration
+// ==================================
+
+class BufferArray::Block
+{
+public:
+	~Block();
+
+	void operator delete(void *);
+	void operator delete(void *, size_t len);
+
+protected:
+	Block(size_t len);
+
+	Block(const Block &);						// Not defined
+	void operator=(const Block &);				// Not defined
+
+	// Allocate the block with the additional space for the
+	// buffered data at the end of the object.
+	void * operator new(size_t len, size_t addl_len);
+	
+public:
+	// Only public entry to get a block.
+	static Block * alloc(size_t len);
+
+public:
+	size_t mLen;
+
+	// *NOTE:  Must be last member of the object.  We'll
+	// overallocate as requested via operator new and index
+	// into the array at will.
+	char mData[1];		
+};
+
+
+// ==================================
+// BufferArray Definitions
+// ==================================
+
+
+BufferArray::BufferArray()
+	: LLCoreInt::RefCounted(true),
+	  mPos(0),
+	  mLen(0)
+{}
+
+
+BufferArray::~BufferArray()
+{
+	for (container_t::iterator it(mBlocks.begin());
+		 it != mBlocks.end();
+		 ++it)
+	{
+		delete *it;
+		*it = NULL;
+	}
+	mBlocks.clear();
+}
+
+
+size_t BufferArray::append(const char * src, size_t len)
+{
+	if (len)
+	{
+		if (mBlocks.size() >= mBlocks.capacity())
+		{
+			mBlocks.reserve(mBlocks.size() + 5);
+		}
+		Block * block = Block::alloc(len);
+		memcpy(block->mData, src, len);
+		mBlocks.push_back(block);
+		mLen += len;
+		mPos = mLen;
+	}
+	return len;
+}
+
+
+char * BufferArray::appendBufferAlloc(size_t len)
+{
+	// If someone asks for zero-length, we give them a valid pointer.
+	if (mBlocks.size() >= mBlocks.capacity())
+	{
+		mBlocks.reserve(mBlocks.size() + 5);
+	}
+	Block * block = Block::alloc(len);
+	mBlocks.push_back(block);
+	mLen += len;
+	mPos = mLen;
+	return block->mData;
+}
+
+
+size_t BufferArray::seek(size_t pos)
+{
+	if (pos > mLen)
+		pos = mLen;
+	mPos = pos;
+	return mPos;
+}
+
+	
+size_t BufferArray::read(char * dst, size_t len)
+{
+	size_t result(0), offset(0);
+	size_t len_limit(mLen - mPos);
+	len = std::min(len, len_limit);
+
+	if (mPos >= mLen || 0 == len)
+		return 0;
+	
+	const int block_limit(mBlocks.size());
+	int block_start(findBlock(mPos, &offset));
+	if (block_start < 0)
+		return 0;
+
+	do
+	{
+		Block & block(*mBlocks[block_start]);
+		size_t block_limit(block.mLen - offset);
+		size_t block_len(std::min(block_limit, len));
+		
+		memcpy(dst, &block.mData[offset], block_len);
+		result += block_len;
+		len -= block_len;
+		dst += block_len;
+		offset = 0;
+		++block_start;
+	}
+	while (len && block_start < block_limit);
+
+	mPos += result;
+	return result;
+}
+
+
+size_t BufferArray::write(const char * src, size_t len)
+{
+	size_t result(0), offset(0);
+	if (mPos > mLen || 0 == len)
+		return 0;
+	
+	const int block_limit(mBlocks.size());
+	int block_start(findBlock(mPos, &offset));
+
+	if (block_start >= 0)
+	{
+		// Some or all of the write will be on top of
+		// existing data.
+		do
+		{
+			Block & block(*mBlocks[block_start]);
+			size_t block_limit(block.mLen - offset);
+			size_t block_len(std::min(block_limit, len));
+		
+			memcpy(&block.mData[offset], src, block_len);
+			result += block_len;
+			len -= block_len;
+			src += block_len;
+			offset = 0;
+			++block_start;
+		}
+		while (len && block_start < block_limit);
+	}
+	mPos += result;
+
+	if (len)
+	{
+		// Some or all of the remaining write data will
+		// be an append.
+		result += append(src, len);
+	}
+
+	return result;
+}
+		
+
+int BufferArray::findBlock(size_t pos, size_t * ret_offset)
+{
+	*ret_offset = 0;
+	if (pos >= mLen)
+		return -1;		// Doesn't exist
+
+	const int block_limit(mBlocks.size());
+	for (int i(0); i < block_limit; ++i)
+	{
+		if (pos < mBlocks[i]->mLen)
+		{
+			*ret_offset = pos;
+			return i;
+		}
+		pos -= mBlocks[i]->mLen;
+	}
+
+	// Shouldn't get here but...
+	return -1;
+}
+
+
+// ==================================
+// BufferArray::Block Definitions
+// ==================================
+
+
+BufferArray::Block::Block(size_t len)
+	: mLen(len)
+{
+	memset(mData, 0, len);
+}
+			
+
+BufferArray::Block::~Block()
+{
+	mLen = 0;
+}
+
+
+void * BufferArray::Block::operator new(size_t len, size_t addl_len)
+{
+	void * mem = new char[len + addl_len + sizeof(void *)];
+	return mem;
+}
+
+
+void BufferArray::Block::operator delete(void * mem)
+{
+	char * cmem = static_cast<char *>(mem);
+	delete [] cmem;
+}
+
+
+void BufferArray::Block::operator delete(void * mem, size_t)
+{
+	operator delete(mem);
+}
+
+
+BufferArray::Block * BufferArray::Block::alloc(size_t len)
+{
+	Block * block = new (len) Block(len);
+	return block;
+}
+	
+
+}  // end namespace LLCore
+
+