Implement a parser that parses the "Range" HTTP header...

net/http/http_byte_range.h

Index: net/http/http_byte_range.h
===================================================================
--- net/http/http_byte_range.h	(revision 0)
+++ net/http/http_byte_range.h	(revision 0)
@@ -0,0 +1,58 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_HTTP_HTTP_BYTE_RANGE_H_
+#define NET_HTTP_HTTP_BYTE_RANGE_H_
+
+#include "base/basictypes.h"
+
+namespace net {
+
+// A container class that represents a "range" specified for range request
+// specified by RFC 2616 Section 14.35.1.
+// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.1
+class HttpByteRange {
+ public:
+  HttpByteRange();
+
+  // Since this class is POD, we use constructor, assignment operator
+  // and destructor provided by compiler.
+  int64 first_byte_position() const { return first_byte_position_; }
+  void set_first_byte_position(int64 value) { first_byte_position_ =  value; }
+
+  int64 last_byte_position() const { return last_byte_position_; }
+  void set_last_byte_position(int64 value) { last_byte_position_ = value; }
+
+  int64 suffix_length() const { return suffix_length_; }
+  void set_suffix_length(int64 value) { suffix_length_ = value; }
+
+  // Returns true if this is a suffix byte range.
+  bool IsSuffixByteRange() const;
+  // Returns true if the first byte position is specified in this request.
+  bool HasFirstBytePosition() const;
+  // Returns true if the last byte position is specified in this request.
+  bool HasLastBytePosition() const;
+
+  // Returns true if this range is valid.
+  bool IsValid() const;
+
+  // A method that when given the size in bytes of a file, adjust the internal
+  // |first_byte_position_| and |last_byte_position_| values according to the
+  // range specified by this object. If the range specified is invalid with
+  // regard to the size or |size| is negative, returns false and there will be
+  // no side effect.
+  // Returns false if this method is called more than once and there will be
+  // no side effect.
+  bool ComputeBounds(int64 size);
+
+ private:
+  int64 first_byte_position_;
+  int64 last_byte_position_;
+  int64 suffix_length_;
+  bool has_computed_bounds_;
+};
+
+}  // namespace net
+
+#endif  // NET_HTTP_HTTP_BYTE_RANGE_H_