Pull and merge from ssh://hg@bitbucket.org/lindenlab/viewer-beta.

1 files changed, 137 insertions, 0 deletions

diff --git a/indra/llcorehttp/bufferarray.h b/indra/llcorehttp/bufferarray.h
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+/**
+ * @file bufferarray.h
+ * @brief Public-facing declaration for the BufferArray scatter/gather class
+ *
+ * $LicenseInfo:firstyear=2012&license=viewerlgpl$
+ * 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
+ * $/LicenseInfo$
+ */
+
+#ifndef	_LLCORE_BUFFER_ARRAY_H_
+#define	_LLCORE_BUFFER_ARRAY_H_
+
+
+#include <cstdlib>
+#include <vector>
+
+#include "_refcounted.h"
+
+
+namespace LLCore
+{
+
+class BufferArrayStreamBuf;
+
+/// A very simple scatter/gather type map for bulk data.  The motivation
+/// for this class is the writedata callback used by libcurl.  Response
+/// bodies are delivered to the caller in a sequence of sequential write
+/// operations and this class captures them without having to reallocate
+/// and move data.
+///
+/// The interface looks a little like a unix file descriptor but only
+/// just.  There is a notion of a current position, starting from 0,
+/// which is used as the position in the data when performing read and
+/// write operations.  The position also moves after various operations:
+/// - seek(...)
+/// - read(...)
+/// - write(...)
+/// - append(...)
+/// - appendBufferAlloc(...)
+/// The object also keeps a total length value which is updated after
+/// write and append operations and beyond which the current position
+/// cannot be set.
+///
+/// Threading:  not thread-safe
+///
+/// Allocation:  Refcounted, heap only.  Caller of the constructor
+/// is given a single refcount.
+///
+class BufferArray : public LLCoreInt::RefCounted
+{
+public:
+	// BufferArrayStreamBuf has intimate knowledge of this
+	// implementation to implement a buffer-free adapter.
+	// Changes here will likely need to be reflected there.
+	friend class BufferArrayStreamBuf;
+	
+	BufferArray();
+
+protected:
+	virtual ~BufferArray();						// Use release()
+
+private:
+	BufferArray(const BufferArray &);			// Not defined
+	void operator=(const BufferArray &);		// Not defined
+
+public:
+	// Internal magic number, may be used by unit tests.
+	static const size_t BLOCK_ALLOC_SIZE = 65540;
+	
+	/// Appends the indicated data to the BufferArray
+	/// modifying current position and total size.  New
+	/// position is one beyond the final byte of the buffer.
+	///
+	/// @return			Count of bytes copied to BufferArray
+	size_t append(const void * src, size_t len);
+
+	/// Similar to @see append(), this call guarantees a
+	/// contiguous block of memory of requested size placed
+	/// at the current end of the BufferArray.  On return,
+	/// the data in the memory is considered valid whether
+	/// the caller writes to it or not.
+	///
+	/// @return			Pointer to contiguous region at end
+	///					of BufferArray of 'len' size.
+	void * appendBufferAlloc(size_t len);
+
+	/// Current count of bytes in BufferArray instance.
+	size_t size() const
+		{
+			return mLen;
+		}
+
+	/// Copies data from the given position in the instance
+	/// to the caller's buffer.  Will return a short count of
+	/// bytes copied if the 'len' extends beyond the data.
+	size_t read(size_t pos, void * dst, size_t len);
+
+	/// Copies data from the caller's buffer to the instance
+	/// at the current position.  May overwrite existing data,
+	/// append data when current position is equal to the
+	/// size of the instance or do a mix of both.
+	size_t write(size_t pos, const void * src, size_t len);
+	
+protected:
+	int findBlock(size_t pos, size_t * ret_offset);
+
+	bool getBlockStartEnd(int block, const char ** start, const char ** end);
+	
+protected:
+	class Block;
+	typedef std::vector<Block *> container_t;
+
+	container_t			mBlocks;
+	size_t				mLen;
+};  // end class BufferArray
+
+
+}  // end namespace LLCore
+
+#endif	// _LLCORE_BUFFER_ARRAY_H_