// ----------------------------------------------------------------------------
// Copyright (C) 2006, 2009 Marcin Kalicinski
//
// Distributed under the Boost Software License, Version 1.0. 
// (See accompanying file LICENSE_1_0.txt or copy at 
// http://www.boost.org/LICENSE_1_0.txt)
//
// For more information, see www.boost.org
// ----------------------------------------------------------------------------
#ifndef BOOST_PROPERTY_TREE_RAPIDXML_HPP_INCLUDED
#define BOOST_PROPERTY_TREE_RAPIDXML_HPP_INCLUDED

//! \file rapidxml.hpp This file contains rapidxml parser and DOM implementation

#include <boost/assert.hpp>
#include <cstdlib>      // For std::size_t
#include <new>          // For placement new

// On MSVC, disable "conditional expression is constant" warning (level 4). 
// This warning is almost impossible to avoid with certain types of templated code
#ifdef _MSC_VER
    #pragma warning(push)
    #pragma warning(disable:4127)   // Conditional expression is constant
#endif

///////////////////////////////////////////////////////////////////////////
// BOOST_PROPERTY_TREE_RAPIDXML_PARSE_ERROR
    
#include <exception>    // For std::exception

#define BOOST_PROPERTY_TREE_RAPIDXML_PARSE_ERROR(what, where) throw parse_error(what, where)

namespace boost { namespace property_tree { namespace detail {namespace rapidxml
{

    //! Parse error exception. 
    //! This exception is thrown by the parser when an error occurs. 
    //! Use what() function to get human-readable error message. 
    //! Use where() function to get a pointer to position within source text where error was detected.
    //! <br><br>
    //! If throwing exceptions by the parser is undesirable, 
    //! it can be disabled by defining RAPIDXML_NO_EXCEPTIONS macro before rapidxml.hpp is included.
    //! This will cause the parser to call rapidxml::parse_error_handler() function instead of throwing an exception.
    //! This function must be defined by the user.
    //! <br><br>
    //! This class derives from <code>std::exception</code> class.
    class parse_error: public std::exception
    {
    
    public:
    
        //! Constructs parse error
        parse_error(const char *wa, void *we)
            : m_what(wa)
            , m_where(we)
        {
        }

        //! Gets human readable description of error.
        //! \return Pointer to null terminated description of the error.
        virtual const char *what() const throw()
        {
            return m_what;
        }

        //! Gets pointer to character data where error happened.
        //! Ch should be the same as char type of xml_document that produced the error.
        //! \return Pointer to location within the parsed string where error occured.
        template<class Ch>
        Ch *where() const
        {
            return reinterpret_cast<Ch *>(m_where);
        }

    private:  

        const char *m_what;
        void *m_where;

    };
}}}}

///////////////////////////////////////////////////////////////////////////
// Pool sizes

#ifndef BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE
    // Size of static memory block of memory_pool.
    // Define BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE before including rapidxml.hpp if you want to override the default value.
    // No dynamic memory allocations are performed by memory_pool until static memory is exhausted.
    #define BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE (64 * 1024)
#endif

#ifndef BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE
    // Size of dynamic memory block of memory_pool.
    // Define BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE before including rapidxml.hpp if you want to override the default value.
    // After the static block is exhausted, dynamic blocks with approximately this size are allocated by memory_pool.
    #define BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE (64 * 1024)
#endif

#ifndef BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT
    // Memory allocation alignment.
    // Define BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT before including rapidxml.hpp if you want to override the default value, which is the size of pointer.
    // All memory allocations for nodes, attributes and strings will be aligned to this value.
    // This must be a power of 2 and at least 1, otherwise memory_pool will not work.
    #define BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT sizeof(void *)
#endif

namespace boost { namespace property_tree { namespace detail {namespace rapidxml
{
    // Forward declarations
    template<class Ch> class xml_node;
    template<class Ch> class xml_attribute;
    template<class Ch> class xml_document;
    
    //! Enumeration listing all node types produced by the parser.
    //! Use xml_node::type() function to query node type.
    enum node_type
    {
        node_document,      //!< A document node. Name and value are empty.
        node_element,       //!< An element node. Name contains element name. Value contains text of first data node.
        node_data,          //!< A data node. Name is empty. Value contains data text.
        node_cdata,         //!< A CDATA node. Name is empty. Value contains data text.
        node_comment,       //!< A comment node. Name is empty. Value contains comment text.
        node_declaration,   //!< A declaration node. Name and value are empty. Declaration parameters (version, encoding and standalone) are in node attributes.
        node_doctype,       //!< A DOCTYPE node. Name is empty. Value contains DOCTYPE text.
        node_pi             //!< A PI node. Name contains target. Value contains instructions.
    };

    ///////////////////////////////////////////////////////////////////////
    // Parsing flags

    //! Parse flag instructing the parser to not create data nodes. 
    //! Text of first data node will still be placed in value of parent element, unless rapidxml::parse_no_element_values flag is also specified.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_no_data_nodes = 0x1;            

    //! Parse flag instructing the parser to not use text of first data node as a value of parent element.
    //! Can be combined with other flags by use of | operator.
    //! Note that child data nodes of element node take precendence over its value when printing. 
    //! That is, if element has one or more child data nodes <em>and</em> a value, the value will be ignored.
    //! Use rapidxml::parse_no_data_nodes flag to prevent creation of data nodes if you want to manipulate data using values of elements.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_no_element_values = 0x2;
    
    //! Parse flag instructing the parser to not place zero terminators after strings in the source text.
    //! By default zero terminators are placed, modifying source text.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_no_string_terminators = 0x4;
    
    //! Parse flag instructing the parser to not translate entities in the source text.
    //! By default entities are translated, modifying source text.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_no_entity_translation = 0x8;
    
    //! Parse flag instructing the parser to disable UTF-8 handling and assume plain 8 bit characters.
    //! By default, UTF-8 handling is enabled.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_no_utf8 = 0x10;
    
    //! Parse flag instructing the parser to create XML declaration node.
    //! By default, declaration node is not created.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_declaration_node = 0x20;
    
    //! Parse flag instructing the parser to create comments nodes.
    //! By default, comment nodes are not created.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_comment_nodes = 0x40;
    
    //! Parse flag instructing the parser to create DOCTYPE node.
    //! By default, doctype node is not created.
    //! Although W3C specification allows at most one DOCTYPE node, RapidXml will silently accept documents with more than one.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_doctype_node = 0x80;
    
    //! Parse flag instructing the parser to create PI nodes.
    //! By default, PI nodes are not created.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_pi_nodes = 0x100;
    
    //! Parse flag instructing the parser to validate closing tag names. 
    //! If not set, name inside closing tag is irrelevant to the parser.
    //! By default, closing tags are not validated.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_validate_closing_tags = 0x200;
    
    //! Parse flag instructing the parser to trim all leading and trailing whitespace of data nodes.
    //! By default, whitespace is not trimmed. 
    //! This flag does not cause the parser to modify source text.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_trim_whitespace = 0x400;

    //! Parse flag instructing the parser to condense all whitespace runs of data nodes to a single space character.
    //! Trimming of leading and trailing whitespace of data is controlled by rapidxml::parse_trim_whitespace flag.
    //! By default, whitespace is not normalized. 
    //! If this flag is specified, source text will be modified.
    //! Can be combined with other flags by use of | operator.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_normalize_whitespace = 0x800;

    // Compound flags
    
    //! Parse flags which represent default behaviour of the parser. 
    //! This is always equal to 0, so that all other flags can be simply ored together.
    //! Normally there is no need to inconveniently disable flags by anding with their negated (~) values.
    //! This also means that meaning of each flag is a <i>negation</i> of the default setting. 
    //! For example, if flag name is rapidxml::parse_no_utf8, it means that utf-8 is <i>enabled</i> by default,
    //! and using the flag will disable it.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_default = 0;
    
    //! A combination of parse flags that forbids any modifications of the source text. 
    //! This also results in faster parsing. However, note that the following will occur:
    //! <ul>
    //! <li>names and values of nodes will not be zero terminated, you have to use xml_base::name_size() and xml_base::value_size() functions to determine where name and value ends</li>
    //! <li>entities will not be translated</li>
    //! <li>whitespace will not be normalized</li>
    //! </ul>
    //! See xml_document::parse() function.
    const int parse_non_destructive = parse_no_string_terminators | parse_no_entity_translation;
    
    //! A combination of parse flags resulting in fastest possible parsing, without sacrificing important data.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_fastest = parse_non_destructive | parse_no_data_nodes;
    
    //! A combination of parse flags resulting in largest amount of data being extracted. 
    //! This usually results in slowest parsing.
    //! <br><br>
    //! See xml_document::parse() function.
    const int parse_full = parse_declaration_node | parse_comment_nodes | parse_doctype_node | parse_pi_nodes | parse_validate_closing_tags;

    ///////////////////////////////////////////////////////////////////////
    // Internals

    //! \cond internal
    namespace internal
    {

        // Struct that contains lookup tables for the parser
        // It must be a template to allow correct linking (because it has static data members, which are defined in a header file).
        template<int Dummy>
        struct lookup_tables
        {
            static const unsigned char lookup_whitespace[256];              // Whitespace table
            static const unsigned char lookup_node_name[256];               // Node name table
            static const unsigned char lookup_text[256];                    // Text table
            static const unsigned char lookup_text_pure_no_ws[256];         // Text table
            static const unsigned char lookup_text_pure_with_ws[256];       // Text table
            static const unsigned char lookup_attribute_name[256];          // Attribute name table
            static const unsigned char lookup_attribute_data_1[256];        // Attribute data table with single quote
            static const unsigned char lookup_attribute_data_1_pure[256];   // Attribute data table with single quote
            static const unsigned char lookup_attribute_data_2[256];        // Attribute data table with double quotes
            static const unsigned char lookup_attribute_data_2_pure[256];   // Attribute data table with double quotes
            static const unsigned char lookup_digits[256];                  // Digits
            static const unsigned char lookup_upcase[256];                  // To uppercase conversion table for ASCII characters
        };

        // Find length of the string
        template<class Ch>
        inline std::size_t measure(const Ch *p)
        {
            const Ch *tmp = p;
            while (*tmp) 
                ++tmp;
            return tmp - p;
        }

        // Compare strings for equality
        template<class Ch>
        inline bool compare(const Ch *p1, std::size_t size1, const Ch *p2, std::size_t size2, bool case_sensitive)
        {
            if (size1 != size2)
                return false;
            if (case_sensitive)
            {
                for (const Ch *end = p1 + size1; p1 < end; ++p1, ++p2)
                    if (*p1 != *p2)
                        return false;
            }
            else
            {
                for (const Ch *end = p1 + size1; p1 < end; ++p1, ++p2)
                    if (lookup_tables<0>::lookup_upcase[static_cast<unsigned char>(*p1)] != lookup_tables<0>::lookup_upcase[static_cast<unsigned char>(*p2)])
                        return false;
            }
            return true;
        }

        template<class Ch>
        inline size_t get_index(const Ch c)
        {
            // If not ASCII char, its semantic is same as plain 'z'.
            // char could be signed, so first stretch and make unsigned.
            unsigned n = c;
            if (n > 127)
            {
                return 'z';
            }
            return c;
        }
    }
    //! \endcond

    ///////////////////////////////////////////////////////////////////////
    // Memory pool
    
    //! This class is used by the parser to create new nodes and attributes, without overheads of dynamic memory allocation.
    //! In most cases, you will not need to use this class directly. 
    //! However, if you need to create nodes manually or modify names/values of nodes, 
    //! you are encouraged to use memory_pool of relevant xml_document to allocate the memory. 
    //! Not only is this faster than allocating them by using <code>new</code> operator, 
    //! but also their lifetime will be tied to the lifetime of document, 
    //! possibly simplyfing memory management. 
    //! <br><br>
    //! Call allocate_node() or allocate_attribute() functions to obtain new nodes or attributes from the pool. 
    //! You can also call allocate_string() function to allocate strings.
    //! Such strings can then be used as names or values of nodes without worrying about their lifetime.
    //! Note that there is no <code>free()</code> function -- all allocations are freed at once when clear() function is called, 
    //! or when the pool is destroyed.
    //! <br><br>
    //! It is also possible to create a standalone memory_pool, and use it 
    //! to allocate nodes, whose lifetime will not be tied to any document.
    //! <br><br>
    //! Pool maintains <code>BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE</code> bytes of statically allocated memory. 
    //! Until static memory is exhausted, no dynamic memory allocations are done.
    //! When static memory is exhausted, pool allocates additional blocks of memory of size <code>BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE</code> each,
    //! by using global <code>new[]</code> and <code>delete[]</code> operators. 
    //! This behaviour can be changed by setting custom allocation routines. 
    //! Use set_allocator() function to set them.
    //! <br><br>
    //! Allocations for nodes, attributes and strings are aligned at <code>BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT</code> bytes.
    //! This value defaults to the size of pointer on target architecture.
    //! <br><br>
    //! To obtain absolutely top performance from the parser,
    //! it is important that all nodes are allocated from a single, contiguous block of memory.
    //! Otherwise, cache misses when jumping between two (or more) disjoint blocks of memory can slow down parsing quite considerably.
    //! If required, you can tweak <code>BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE</code>, <code>BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE</code> and <code>BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT</code> 
    //! to obtain best wasted memory to performance compromise.
    //! To do it, define their values before rapidxml.hpp file is included.
    //! \param Ch Character type of created nodes. 
    template<class Ch = char>
    class memory_pool
    {
        
    public:

        //! \cond internal
        typedef void *(alloc_func)(std::size_t);       // Type of user-defined function used to allocate memory
        typedef void (free_func)(void *);              // Type of user-defined function used to free memory
        //! \endcond
        
        //! Constructs empty pool with default allocator functions.
        memory_pool()
            : m_alloc_func(0)
            , m_free_func(0)
        {
            init();
        }

        //! Destroys pool and frees all the memory. 
        //! This causes memory occupied by nodes allocated by the pool to be freed.
        //! Nodes allocated from the pool are no longer valid.
        ~memory_pool()
        {
            clear();
        }

        //! Allocates a new node from the pool, and optionally assigns name and value to it. 
        //! If the allocation request cannot be accomodated, this function will throw <code>std::bad_alloc</code>.
        //! If exceptions are disabled by defining RAPIDXML_NO_EXCEPTIONS, this function
        //! will call rapidxml::parse_error_handler() function.
        //! \param type Type of node to create.
        //! \param name Name to assign to the node, or 0 to assign no name.
        //! \param value Value to assign to the node, or 0 to assign no value.
        //! \param name_size Size of name to assign, or 0 to automatically calculate size from name string.
        //! \param value_size Size of value to assign, or 0 to automatically calculate size from value string.
        //! \return Pointer to allocated node. This pointer will never be NULL.
        xml_node<Ch> *allocate_node(node_type type, 
                                    const Ch *name = 0, const Ch *value = 0, 
                                    std::size_t name_size = 0, std::size_t value_size = 0)
        {
            void *memory = allocate_aligned(sizeof(xml_node<Ch>));
            xml_node<Ch> *node = new(memory) xml_node<Ch>(type);
            if (name)
            {
                if (name_size > 0)
                    node->name(name, name_size);
                else
                    node->name(name);
            }
            if (value)
            {
                if (value_size > 0)
                    node->value(value, value_size);
                else
                    node->value(value);
            }
            return node;
        }

        //! Allocates a new attribute from the pool, and optionally assigns name and value to it.
        //! If the allocation request cannot be accomodated, this function will throw <code>std::bad_alloc</code>.
        //! If exceptions are disabled by defining RAPIDXML_NO_EXCEPTIONS, this function
        //! will call rapidxml::parse_error_handler() function.
        //! \param name Name to assign to the attribute, or 0 to assign no name.
        //! \param value Value to assign to the attribute, or 0 to assign no value.
        //! \param name_size Size of name to assign, or 0 to automatically calculate size from name string.
        //! \param value_size Size of value to assign, or 0 to automatically calculate size from value string.
        //! \return Pointer to allocated attribute. This pointer will never be NULL.
        xml_attribute<Ch> *allocate_attribute(const Ch *name = 0, const Ch *value = 0, 
                                              std::size_t name_size = 0, std::size_t value_size = 0)
        {
            void *memory = allocate_aligned(sizeof(xml_attribute<Ch>));
            xml_attribute<Ch> *attribute = new(memory) xml_attribute<Ch>;
            if (name)
            {
                if (name_size > 0)
                    attribute->name(name, name_size);
                else
                    attribute->name(name);
            }
            if (value)
            {
                if (value_size > 0)
                    attribute->value(value, value_size);
                else
                    attribute->value(value);
            }
            return attribute;
        }

        //! Allocates a char array of given size from the pool, and optionally copies a given string to it.
        //! If the allocation request cannot be accomodated, this function will throw <code>std::bad_alloc</code>.
        //! If exceptions are disabled by defining RAPIDXML_NO_EXCEPTIONS, this function
        //! will call rapidxml::parse_error_handler() function.
        //! \param source String to initialize the allocated memory with, or 0 to not initialize it.
        //! \param size Number of characters to allocate, or zero to calculate it automatically from source string length; if size is 0, source string must be specified and null terminated.
        //! \return Pointer to allocated char array. This pointer will never be NULL.
        Ch *allocate_string(const Ch *source = 0, std::size_t size = 0)
        {
            BOOST_ASSERT(source || size);     // Either source or size (or both) must be specified
            if (size == 0)
                size = internal::measure(source) + 1;
            Ch *result = static_cast<Ch *>(allocate_aligned(size * sizeof(Ch)));
            if (source)
                for (std::size_t i = 0; i < size; ++i)
                    result[i] = source[i];
            return result;
        }

        //! Clones an xml_node and its hierarchy of child nodes and attributes.
        //! Nodes and attributes are allocated from this memory pool.
        //! Names and values are not cloned, they are shared between the clone and the source.
        //! Result node can be optionally specified as a second parameter, 
        //! in which case its contents will be replaced with cloned source node.
        //! This is useful when you want to clone entire document.
        //! \param source Node to clone.
        //! \param result Node to put results in, or 0 to automatically allocate result node
        //! \return Pointer to cloned node. This pointer will never be NULL.
        xml_node<Ch> *clone_node(const xml_node<Ch> *source, xml_node<Ch> *result = 0)
        {
            // Prepare result node
            if (result)
            {
                result->remove_all_attributes();
                result->remove_all_nodes();
                result->type(source->type());
            }
            else
                result = allocate_node(source->type());

            // Clone name and value
            result->name(source->name(), source->name_size());
            result->value(source->value(), source->value_size());

            // Clone child nodes and attributes
            for (xml_node<Ch> *child = source->first_node(); child; child = child->next_sibling())
                result->append_node(clone_node(child));
            for (xml_attribute<Ch> *attr = source->first_attribute(); attr; attr = attr->next_attribute())
                result->append_attribute(allocate_attribute(attr->name(), attr->value(), attr->name_size(), attr->value_size()));

            return result;
        }

        //! Clears the pool. 
        //! This causes memory occupied by nodes allocated by the pool to be freed.
        //! Any nodes or strings allocated from the pool will no longer be valid.
        void clear()
        {
            while (m_begin != m_static_memory)
            {
                char *previous_begin = reinterpret_cast<header *>(align(m_begin))->previous_begin;
                if (m_free_func)
                    m_free_func(m_begin);
                else
                    delete[] m_begin;
                m_begin = previous_begin;
            }
            init();
        }

        //! Sets or resets the user-defined memory allocation functions for the pool.
        //! This can only be called when no memory is allocated from the pool yet, otherwise results are undefined.
        //! Allocation function must not return invalid pointer on failure. It should either throw,
        //! stop the program, or use <code>longjmp()</code> function to pass control to other place of program. 
        //! If it returns invalid pointer, results are undefined.
        //! <br><br>
        //! User defined allocation functions must have the following forms:
        //! <br><code>
        //! <br>void *allocate(std::size_t size);
        //! <br>void free(void *pointer);
        //! </code><br>
        //! \param af Allocation function, or 0 to restore default function
        //! \param ff Free function, or 0 to restore default function
        void set_allocator(alloc_func *af, free_func *ff)
        {
            BOOST_ASSERT(m_begin == m_static_memory && m_ptr == align(m_begin));    // Verify that no memory is allocated yet
            m_alloc_func = af;
            m_free_func = ff;
        }

    private:

        struct header
        {
            char *previous_begin;
        };

        void init()
        {
            m_begin = m_static_memory;
            m_ptr = align(m_begin);
            m_end = m_static_memory + sizeof(m_static_memory);
        }
        
        char *align(char *ptr)
        {
            std::size_t alignment = ((BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT - (std::size_t(ptr) & (BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT - 1))) & (BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT - 1));
            return ptr + alignment;
        }
        
        char *allocate_raw(std::size_t size)
        {
            // Allocate
            void *memory;   
            if (m_alloc_func)   // Allocate memory using either user-specified allocation function or global operator new[]
            {
                memory = m_alloc_func(size);
                BOOST_ASSERT(memory); // Allocator is not allowed to return 0, on failure it must either throw, stop the program or use longjmp
            }
            else
            {
                memory = new char[size];
            }
            return static_cast<char *>(memory);
        }
        
        void *allocate_aligned(std::size_t size)
        {
            // Calculate aligned pointer
            char *result = align(m_ptr);

            // If not enough memory left in current pool, allocate a new pool
            if (result + size > m_end)
            {
                // Calculate required pool size (may be bigger than BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE)
                std::size_t pool_size = BOOST_PROPERTY_TREE_RAPIDXML_DYNAMIC_POOL_SIZE;
                if (pool_size < size)
                    pool_size = size;
                
                // Allocate
                std::size_t alloc_size = sizeof(header) + (2 * BOOST_PROPERTY_TREE_RAPIDXML_ALIGNMENT - 2) + pool_size;     // 2 alignments required in worst case: one for header, one for actual allocation
                char *raw_memory = allocate_raw(alloc_size);
                    
                // Setup new pool in allocated memory
                char *pool = align(raw_memory);
                header *new_header = reinterpret_cast<header *>(pool);
                new_header->previous_begin = m_begin;
                m_begin = raw_memory;
                m_ptr = pool + sizeof(header);
                m_end = raw_memory + alloc_size;

                // Calculate aligned pointer again using new pool
                result = align(m_ptr);
            }

            // Update pool and return aligned pointer
            m_ptr = result + size;
            return result;
        }

        char *m_begin;                                      // Start of raw memory making up current pool
        char *m_ptr;                                        // First free byte in current pool
        char *m_end;                                        // One past last available byte in current pool
        char m_static_memory[BOOST_PROPERTY_TREE_RAPIDXML_STATIC_POOL_SIZE];    // Static raw memory
        alloc_func *m_alloc_func;                           // Allocator function, or 0 if default is to be used
        free_func *m_free_func;                             // Free function, or 0 if default is to be used
    };

    ///////////////////////////////////////////////////////////////////////////
    // XML base

    //! Base class for xml_node and xml_attribute implementing common functions: 
    //! name(), name_size(), value(), value_size() and parent().
    //! \param Ch Character type to use
    template<class Ch = char>
    class xml_base
    {

    public:
        
        ///////////////////////////////////////////////////////////////////////////
        // Construction & destruction
    
        // Construct a base with empty name, value and parent
        xml_base()
            : m_name(0)
            , m_value(0)
            , m_parent(0)
        {
        }

        ///////////////////////////////////////////////////////////////////////////
        // Node data access
    
        //! Gets name of the node. 
        //! Interpretation of name depends on type of node.
        //! Note that name will not be zero-terminated if rapidxml::parse_no_string_terminators option was selected during parse.
        //! <br><br>
        //! Use name_size() function to determine length of the name.
        //! \return Name of node, or empty string if node has no name.
        Ch *name() const
        {
            return m_name ? m_name : nullstr();
        }

        //! Gets size of node name, not including terminator character.
        //! This function works correctly irrespective of whether name is or is not zero terminated.
        //! \return Size of node name, in characters.
        std::size_t name_size() const
        {
            return m_name ? m_name_size : 0;
        }

        //! Gets value of node. 
        //! Interpretation of value depends on type of node.
        //! Note that value will not be zero-terminated if rapidxml::parse_no_string_terminators option was selected during parse.
        //! <br><br>
        //! Use value_size() function to determine length of the value.
        //! \return Value of node, or empty string if node has no value.
        Ch *value() const
        {
            return m_value ? m_value : nullstr();
        }

        //! Gets size of node value, not including terminator character.
        //! This function works correctly irrespective of whether value is or is not zero terminated.
        //! \return Size of node value, in characters.
        std::size_t value_size() const
        {
            return m_value ? m_value_size : 0;
        }

        ///////////////////////////////////////////////////////////////////////////
        // Node modification
    
        //! Sets name of node to a non zero-terminated string.
        //! See \ref ownership_of_strings.
        //! <br><br>
        //! Note that node does not own its name or value, it only stores a pointer to it. 
        //! It will not delete or otherwise free the pointer on destruction.
        //! It is reponsibility of the user to properly manage lifetime of the string.
        //! The easiest way to achieve it is to use memory_pool of the document to allocate the string -
        //! on destruction of the document the string will be automatically freed.
        //! <br><br>
        //! Size of name must be specified separately, because name does not have to be zero terminated.
        //! Use name(const Ch *) function to have the length automatically calculated (string must be zero terminated).
        //! \param n Name of node to set. Does not have to be zero terminated.
        //! \param size Size of name, in characters. This does not include zero terminator, if one is present.
        void name(const Ch *n, std::size_t size)
        {
            m_name = const_cast<Ch *>(n);
            m_name_size = size;
        }

        //! Sets name of node to a zero-terminated string.
        //! See also \ref ownership_of_strings and xml_node::name(const Ch *, std::size_t).
        //! \param n Name of node to set. Must be zero terminated.
        void name(const Ch *n)
        {
            name(n, internal::measure(n));
        }

        //! Sets value of node to a non zero-terminated string.
        //! See \ref ownership_of_strings.
        //! <br><br>
        //! Note that node does not own its name or value, it only stores a pointer to it. 
        //! It will not delete or otherwise free the pointer on destruction.
        //! It is reponsibility of the user to properly manage lifetime of the string.
        //! The easiest way to achieve it is to use memory_pool of the document to allocate the string -
        //! on destruction of the document the string will be automatically freed.
        //! <br><br>
        //! Size of value must be specified separately, because it does not have to be zero terminated.
        //! Use value(const Ch *) function to have the length automatically calculated (string must be zero terminated).
        //! <br><br>
        //! If an element has a child node of type node_data, it will take precedence over element value when printing.
        //! If you want to manipulate data of elements using values, use parser flag rapidxml::parse_no_data_nodes to prevent creation of data nodes by the parser.
        //! \param val value of node to set. Does not have to be zero terminated.
        //! \param size Size of value, in characters. This does not include zero terminator, if one is present.
        void value(const Ch *val, std::size_t size)
        {
            m_value = const_cast<Ch *>(val);
            m_value_size = size;
        }

        //! Sets value of node to a zero-terminated string.
        //! See also \ref ownership_of_strings and xml_node::value(const Ch *, std::size_t).
        //! \param val Vame of node to set. Must be zero terminated.
        void value(const Ch *val)
        {
            this->value(val, internal::measure(val));
        }

        ///////////////////////////////////////////////////////////////////////////
        // Related nodes access
    
        //! Gets node parent.
        //! \return Pointer to parent node, or 0 if there is no parent.
        xml_node<Ch> *parent() const
        {
            return m_parent;
        }

    protected:

        // Return empty string
        static Ch *nullstr()
        {
            static Ch zero = Ch('\0');
            return &zero;
        }

        Ch *m_name;                         // Name of node, or 0 if no name
        Ch *m_value;                        // Value of node, or 0 if no value
        std::size_t m_name_size;            // Length of node name, or undefined of no name
        std::size_t m_value_size;           // Length of node value, or undefined if no value
        xml_node<Ch> *m_parent;             // Pointer to parent node, or 0 if none

    };

    //! Class representing attribute node of XML document. 
    //! Each attribute has name and value strings, which are available through name() and value() functions (inherited from xml_base).
    //! Note that after parse, both name and value of attribute will point to interior of source text used for parsing. 
    //! Thus, this text must persist in memory for the lifetime of attribute.
    //! \param Ch Character type to use.
    template<class Ch = char>
    class xml_attribute: public xml_base<Ch>
    {

        friend class xml_node<Ch>;
    
    public:

        ///////////////////////////////////////////////////////////////////////////
        // Construction & destruction
    
        //! Constructs an empty attribute with the specified type. 
        //! Consider using memory_pool of appropriate xml_document if allocating attributes manually.
        xml_attribute()
        {
        }

        ///////////////////////////////////////////////////////////////////////////
        // Related nodes access
    
        //! Gets document of which attribute is a child.
        //! \return Pointer to document that contains this attribute, or 0 if there is no parent document.
        xml_document<Ch> *document() const
        {
            if (xml_node<Ch> *node = this->parent())
            {
                while (node->parent())
                    node = node->parent();
                return node->type() == node_document ? static_cast<xml_document<Ch> *>(node) : 0;
            }
            else
                return 0;
        }

        //! Gets previous attribute, optionally matching attribute name. 
        //! \param n Name of attribute to find, or 0 to return previous attribute regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found attribute, or 0 if not found.
        xml_attribute<Ch> *previous_attribute(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_attribute<Ch> *attribute = m_prev_attribute; attribute; attribute = attribute->m_prev_attribute)
                    if (internal::compare(attribute->name(), attribute->name_size(), n, nsize, case_sensitive))
                        return attribute;
                return 0;
            }
            else
                return this->m_parent ? m_prev_attribute : 0;
        }

        //! Gets next attribute, optionally matching attribute name. 
        //! \param n Name of attribute to find, or 0 to return next attribute regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found attribute, or 0 if not found.
        xml_attribute<Ch> *next_attribute(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_attribute<Ch> *attribute = m_next_attribute; attribute; attribute = attribute->m_next_attribute)
                    if (internal::compare(attribute->name(), attribute->name_size(), n, nsize, case_sensitive))
                        return attribute;
                return 0;
            }
            else
                return this->m_parent ? m_next_attribute : 0;
        }

    private:

        xml_attribute<Ch> *m_prev_attribute;        // Pointer to previous sibling of attribute, or 0 if none; only valid if parent is non-zero
        xml_attribute<Ch> *m_next_attribute;        // Pointer to next sibling of attribute, or 0 if none; only valid if parent is non-zero
    
    };

    ///////////////////////////////////////////////////////////////////////////
    // XML node

    //! Class representing a node of XML document. 
    //! Each node may have associated name and value strings, which are available through name() and value() functions. 
    //! Interpretation of name and value depends on type of the node.
    //! Type of node can be determined by using type() function.
    //! <br><br>
    //! Note that after parse, both name and value of node, if any, will point interior of source text used for parsing. 
    //! Thus, this text must persist in the memory for the lifetime of node.
    //! \param Ch Character type to use.
    template<class Ch = char>
    class xml_node: public xml_base<Ch>
    {

    public:

        ///////////////////////////////////////////////////////////////////////////
        // Construction & destruction
    
        //! Constructs an empty node with the specified type. 
        //! Consider using memory_pool of appropriate document to allocate nodes manually.
        //! \param t Type of node to construct.
        xml_node(node_type t)
            : m_type(t)
            , m_first_node(0)
            , m_first_attribute(0)
        {
        }

        ///////////////////////////////////////////////////////////////////////////
        // Node data access
    
        //! Gets type of node.
        //! \return Type of node.
        node_type type() const
        {
            return m_type;
        }

        ///////////////////////////////////////////////////////////////////////////
        // Related nodes access
    
        //! Gets document of which node is a child.
        //! \return Pointer to document that contains this node, or 0 if there is no parent document.
        xml_document<Ch> *document() const
        {
            xml_node<Ch> *node = const_cast<xml_node<Ch> *>(this);
            while (node->parent())
                node = node->parent();
            return node->type() == node_document ? static_cast<xml_document<Ch> *>(node) : 0;
        }

        //! Gets first child node, optionally matching node name.
        //! \param n Name of child to find, or 0 to return first child regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found child, or 0 if not found.
        xml_node<Ch> *first_node(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_node<Ch> *child = m_first_node; child; child = child->next_sibling())
                    if (internal::compare(child->name(), child->name_size(), n, nsize, case_sensitive))
                        return child;
                return 0;
            }
            else
                return m_first_node;
        }

        //! Gets last child node, optionally matching node name. 
        //! Behaviour is undefined if node has no children.
        //! Use first_node() to test if node has children.
        //! \param n Name of child to find, or 0 to return last child regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found child, or 0 if not found.
        xml_node<Ch> *last_node(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            BOOST_ASSERT(m_first_node);  // Cannot query for last child if node has no children
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_node<Ch> *child = m_last_node; child; child = child->previous_sibling())
                    if (internal::compare(child->name(), child->name_size(), n, nsize, case_sensitive))
                        return child;
                return 0;
            }
            else
                return m_last_node;
        }

        //! Gets previous sibling node, optionally matching node name. 
        //! Behaviour is undefined if node has no parent.
        //! Use parent() to test if node has a parent.
        //! \param n Name of sibling to find, or 0 to return previous sibling regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found sibling, or 0 if not found.
        xml_node<Ch> *previous_sibling(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            BOOST_ASSERT(this->m_parent);     // Cannot query for siblings if node has no parent
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_node<Ch> *sibling = m_prev_sibling; sibling; sibling = sibling->m_prev_sibling)
                    if (internal::compare(sibling->name(), sibling->name_size(), n, nsize, case_sensitive))
                        return sibling;
                return 0;
            }
            else
                return m_prev_sibling;
        }

        //! Gets next sibling node, optionally matching node name. 
        //! Behaviour is undefined if node has no parent.
        //! Use parent() to test if node has a parent.
        //! \param n Name of sibling to find, or 0 to return next sibling regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found sibling, or 0 if not found.
        xml_node<Ch> *next_sibling(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            BOOST_ASSERT(this->m_parent);     // Cannot query for siblings if node has no parent
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_node<Ch> *sibling = m_next_sibling; sibling; sibling = sibling->m_next_sibling)
                    if (internal::compare(sibling->name(), sibling->name_size(), n, nsize, case_sensitive))
                        return sibling;
                return 0;
            }
            else
                return m_next_sibling;
        }

        //! Gets first attribute of node, optionally matching attribute name.
        //! \param n Name of attribute to find, or 0 to return first attribute regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name, in characters, or 0 to have size calculated automatically from string
        //! \param case_sensitive Should name comparison be case-sensitive; non case-sensitive comparison works properly only for ASCII characters
        //! \return Pointer to found attribute, or 0 if not found.
        xml_attribute<Ch> *first_attribute(const Ch *n = 0, std::size_t nsize = 0, bool case_sensitive = true) const
        {
            if (n)
            {
                if (nsize == 0)
                    nsize = internal::measure(n);
                for (xml_attribute<Ch> *attribute = m_first_attribute; attribute; attribute = attribute->m_next_attribute)
                    if (internal::compare(attribute->name(), attribute->name_size(), n, nsize, case_sensitive))
                        return attribute;
                return 0;
            }
            else
                return m_first_attribute;
        }

        //! Gets last attribute of node, optionally matching attribute name.
        //! \param n Name of attribute to find, or 0 to return last attribute regardless of its name; this string doesn't have to be zero-terminated if nsize is non-zero
        //! \param nsize Size of name…