(*
 * LibAxl: C Header file to Free Pascal translation.
 * Copyright (C) 2009, Wimpie Nortje <wimpienortje@gmail.com>
 *)

(*
 *  LibAxl:  Another XML library
 *  Copyright (C) 2006 Advanced Software Production Line, S.L.
 *
 *  This program 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; either version 2.1 of
 *  the License, or (at your option) any later version.
 *
 *  This program 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 program; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307 USA
 *  
 *  You may find a copy of the license under this software is released
 *  at COPYING file. This is LGPL software: you are welcome to
 *  develop proprietary applications using this library without any
 *  royalty or fee but returning back any change, improvement or
 *  addition in the form of source code, project image, documentation
 *  patches, etc. 
 *
 *  For commercial support on build XML enabled solutions contact us:
 *          
 *      Postal address:
 *         Advanced Software Production Line, S.L.
 *         Edificio Alius A, Oficina 102,
 *         C/ Antonio Suarez Nº 10,
 *         Alcalá de Henares 28802 Madrid
 *         Spain
 *
 *      Email address:
 *         info@aspl.es - http://www.aspl.es/xml
 *)

(* include platform specific configuration *)
//#include <axl_config.h>
{TODO: axl config}

{$IFDEF FPC}
{TODO}
//#define __AXL_PRETTY_FUNCTION__ {$I %FUNCTION%}
//#define __AXL_LINE__            {$I %LINE%}
//#define __AXL_FILE__            {$I %FILE%}
//^^^^replace with the macros
{$ENDIF}

(**
 * \defgroup axl_decl_module Axl Declarations: Common Axl declarations, Types, macros, and support functions.
 *)

(**
 * \addtogroup axl_decl_module
 * @{
 *)


(**
 * @brief Axl XML document type definition.
 *
 * This type represents a reference to an entiry XML document loaded
 * into memory. Functions to be used to load XML document could be the
 * following:
 * 
 *  - \ref axl_doc_parse
 *  - \ref axl_doc_parse_strings
 *  - \ref axl_doc_parse_from_file
 * 
 * You can also create an empty document by using \ref axl_doc_create
 * and fill the initial root node using the \ref axl_doc_set_root
 * function. Once the document have an initial root node, you can add
 * more nodes as childs to the root element previously added.
 * 
 * Check the \ref axl_doc_module "axlDoc API reference" to get more
 * information.
 *)
type
  PaxlDoc = Pointer;

(**
 * @brief An abstraction that allows to hold an xml node or any other
 * content that can be found inside an xml node: comments, content,
 * CDATA-content, PI, entity references.
 *
 * This type is mainly used inside the MIXED API, which allows to get
 * access to every particular item found inside a particular node
 * (\ref axlNode). Every item has a type (\ref AxlItemType) and a
 * content that is being encapsulated and usually accessed by \ref
 * axl_item_get_data.
 *
 * Check the \ref axl_item_module "Axl Item interface" for more information.
 *)
type
  PaxlItem = Pointer;

(**
 * @internal Factory allocation type.
 *)
type
  PaxlFactory = Pointer;

(**
 * @internal String factory allocation type.
 *)
type
  PaxlStrFactory = Pointer;

(**
 * @brief Axl XML node type definition.
 *
 * This type reference represents a single XML node. To create a xml node you can use:
 * 
 * - \ref axl_node_create
 * 
 * To get the node name or if the node have childs or if it is empty,
 * you can use the following functions:
 *
 * - \ref axl_node_get_name
 * - \ref axl_node_is_empty
 * - \ref axl_node_have_childs
 *
 * To get the \ref axlNode content you can use the following
 * functions:
 * 
 * - \ref axl_node_get_content
 * - \ref axl_node_get_content_copy
 * - \ref axl_node_get_content_trans
 *
 * For attributes manipulation, you can using the following functions
 * to set them and retrieve them:
 * 
 * - \ref axl_node_get_attribute_value
 * - \ref axl_node_get_attribute_value_copy
 * - \ref axl_node_get_attribute_value_trans
 *
 * To retrive childs number or childs inside the given \ref axlNode
 * you can use the following function:
 * 
 * - \ref axl_node_get_child_num
 * - \ref axl_node_get_child_nth
 *
 * You can also use the following functions to get the parent node for
 * a provided xml node child and the next xml node found at the same
 * level, for a provided xml node reference.
 *
 * - \ref axl_node_get_parent
 * - \ref axl_node_get_next
 * 
 * Check the axlNode \ref axl_node_module "API for more information".
 *)
type
  PaxlNode = Pointer;

(**
 * @brief Public cursor type used to iterate over attributes installed
 * on a particular node (see \ref axl_node_attr_cursor_new to get examples and more information).
 *)
type
  PaxlAttrCursor = Pointer;

(**
 * @brief Axl DTD entity representation.
 *)
type
  PPaxlDtd = ^PaxlDtd;
  PaxlDtd = Pointer;

(**
 * @brief Axl DTD entity element declaration.
 *)
type
  PaxlDtdElement = Pointer;

(**
 * @brief Axl DTD item list element declaration.
 *)
type
  PaxlDtdElementList = Pointer;

(**
 * @brief Axl DTD item list element declaration.
 *)
type
  PaxlDtdElementListNode = Pointer;

(**
 * @brief Axl DTD attribute declaration (<!ATTLIST..>)
 *)
type
  PaxlDtdAttribute = Pointer;

(**
 * @brief Axl DTD attribute list decleration inside \ref axlDtdAttribute.
 *)
type
  PaxlDtdAttributeDecl = Pointer;

(**
 * @brief Axl DTD entity declaration (<!ENTITY support>)
 *)
type
  PaxlDtdEntity = Pointer;

(**
 * @brief Support type definition for \ref axlDtdEntity, which holds
 * information about external resource pointed by the \ref
 * axlDtdEntity instance.
 *)
type
  PaxlDtdEntityExternalData = Pointer;

(**
 * @brief Declares the entity type for a provided \ref axlDtdEntity.
 *)
type
  TaxlDtdEntityType = (
  	(**
  	 * @brief The \ref axlDtdEntity definition represents a
  	 * general entity definition (that comes without % before the
  	 * entity name).
  	 *)
  	GENERAL_ENTITY,
  	(**
  	 * @brief The \ref axlDtdEntity definition represents a
  	 * parameter entity definition (that comes with a % before the
  	 * entity name, making this entity definition to be only
  	 * usable from a DTD definition).
  	 *)
  	PARAMETER_ENTITY
  );

(**
 * @brief Attribute type declaration (the type of the attribute
 * constrain). This type is used to identifier the attribute contains
 * applied to the node selected.
 *)
type
  TAxlDtdAttributeType = (
  	(**
  	 * @brief The attribute type is defined but its content is
  	 * CDATA (any string value is allowed), activated when used 'CDATA'.
  	 *)
  	CDATA_ATTRIBUTE,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'ID'.
  	 *)
  	TOKENIZED_TYPE_ID,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'IDREF'.
  	 *)
  	TOKENIZED_TYPE_IDREF,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'IDREFS'.
  	 *)
  	TOKENIZED_TYPE_IDREFS,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'ENTITY'.
  	 *)
  	TOKENIZED_TYPE_ENTITY,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'ENTITIES'.
  	 *)
  	TOKENIZED_TYPE_ENTITIES,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'NMTOKEN'.
  	 *)
  	TOKENIZED_TYPE_NMTOKEN,
  	(**
  	 * @brief Especific token declaration that implicitly contrain
  	 * the node attribute value, activated when used 'NMTOKENS'.
  	 *)
  	TOKENIZED_TYPE_NMTOKENS,
  	(**
  	 * @brief The attribute type declaration is constrained to a
  	 * set of values. This values are considered as an
  	 * enumeration.
  	 *)
  	ENUMERATION_TYPE,
  	(**
  	 * @brief Attribute type not supported yet (although defined).
  	 *)
  	NOTATION_TYPE
  );

(**
 * @brief Defines the DTD attribute declaration default state.
 *)
type
  TAxlDtdAttributeDefaults = (
  	(**
  	 * @brief The attribute is required as especified by the
  	 * attribute declaration.
  	 *)
  	ATT_REQUIRED,
  	(**
  	 * @brief The attribute is not requried, however, if it
  	 * appears it must follow the attribute type declaration.
  	 *)
  	ATT_IMPLIED,
  	(**
  	 * @brief The attribute must appear and have the value
  	 * provided as the default.
  	 *)
  	ATT_FIXED
  );

(**
 * @brief The type of the DTD sequences stored by the \ref
 * axlDtdElementList.
 *)
type
  TAxlDtdNestedType = (
  	(**
  	 * @internal
  	 *
  	 * Internal value used by the library to support mixing
  	 * content seperator types detection.
  	 *)
  	STILL_UNDEF  := 0,
  	(**
  	 * @brief Represents that the item selection is configured to
  	 * be a choice (a selection allowed from any item inside the
  	 * collection).
  	 *)
  	CHOICE        := 1,
  	(**
  	 * @brief Represents that the item selection is configured to
  	 * select each item in the order they apper.
  	 *)
  	SEQUENCE      := 2
  );

(**
 * @brief An indication of the element type stored on the provided
 * \ref axlDtdElementListNode reference.
 *
 * An \ref axlDtdElementListNode reference could contain a single
 * reference to a content particule name, that is the XML node name to
 * be allowed to be used at the provided position or a reference to an
 * \ref axlDtdElementList which contains a nested list containing more
 * content particules.
 * 
 *)
type
  TNodeType = (
  	(**
  	 * @internal
  	 * Represents the not defined value.
  	 *)
  	AXL_ELEMENT_NOT_DEFINED := 1,
  	(**
  	 * @brief The reference contains an \ref axlDtdElementList.
  	 *)
  	AXL_ELEMENT_LIST := 2,
  	(**
  	 * @brief The reference contains a reference to a leaf node, a
  	 * content particule.
  	 *)
  	AXL_ELEMENT_NODE := 3
  );

(**
 * @brief DTD element type enumeration.
 *
 * While using DTD declaration, <b>ELEMENT</b> used to define how your
 * xml document is structured and constrained, are clasified using the
 * following values.
 *
 * This type specification must not be confused with \ref NodeType,
 * which is the configuration for an element, inside the content DTD
 * element specification.
 *)
type
  TAxlDtdElementType = (
  	(**
  	 * @internal
  	 *
  	 * Internal value to avoid confusing EMPTY declaration with a
  	 * non-defined value.
  	 *)
  	ELEMENT_TYPE_UNKNOWN := 0,
  	(**
  	 * @brief Used to represent that the element declaration have
  	 * no content inside it. This includes not only PCDATA (data
  	 * stored between xml tags) but also any child declaration.
  	 *)
  	ELEMENT_TYPE_EMPTY := 1,
  	(**
  	 * @brief Used to represent that the element used in your xml
  	 * document could contain anthing without any contraint.
  	 *)
  	ELEMENT_TYPE_ANY := 2,
  	(**
  	 * @brief Used to represent that the following xml node have
  	 * content not only defined by a set of allowed xml nodes but
  	 * also PCDATA.
  	 *)
  	ELEMENT_TYPE_MIXED := 3,
  	(**
  	 * @brief Used to represent that the folowing xml node have
  	 * only xml nodes as content, in the form of xml childs,
  	 * without inlucing PCDATA.
  	 *)
  	ELEMENT_TYPE_CHILDREN := 4,
  	(**
  	 * @brief Used to represent that the DTD element specification
  	 * contains only PCDATA. No child nodes or childs nodes mixed
  	 * with PCDATA.
  	 *)
  	ELEMENT_TYPE_PCDATA := 5
  );

(**
 * @brief Current configuration for elements definied inside a ELEMENT
 * DTD declaration.
 *)
type
  TAxlDtdTimes = (
  	(**
  	 * @internal
  	 *
  	 * Internal representation to identify wrong repetition
  	 * especification values.
  	 *)
  	DTD_TIMES_UNKNOWN = 0,
  	(**
  	 * Current configuration for DTD element content specification
  	 * signals that it must appear one and only one times.
  	 *)
  	ONE_AND_ONLY_ONE  = 1,
  	(**
  	 * Current configuration for DTD element content specification
  	 * signals that it could appear zero or one time.
  	 *)
  	ZERO_OR_ONE       = 2,
  	(**
  	 * Current configuration for DTD element content specification
  	 * signals
  	 *)
  	ZERO_OR_MANY      = 3,
  	(**
  	 * Current configuration for DTD element content specification
  	 * signals that it must appear one up to many times.
  	 *)
  	ONE_OR_MANY       = 4
  );

(**
 * @brief Item types that can hold an xml node (\ref axlNode).
 *
 * \ref AxlItemType is used to notify the type for a particular item
 * (\ref axlItem) that is stored as a child on a particular \ref
 * axlNode.
 *
 * This is mainly used inside the MIXED API, which is the way that Axl
 * exposes the content of a xml node that is expected to contain more
 * nodes mixed with more content.
 *
 * Each type represents a particular basic unit that could be found as
 * a child item inside an xml node.
 *)
type
  TAxlItemType = (
  	(**
  	 * @brief The \ref axlItem is encapsulating another item
  	 * node. Calling to \ref axl_item_get_data will return a
  	 * reference to an \ref axlNode.
  	 *
  	 *)
  	ITEM_NODE      := 1 shl 0,
  	(**
  	 * @brief The \ref axlItem is encapsulating an node
  	 * content. Calling to the convenience function \ref
  	 * axl_item_get_content to get the content and the size that
  	 * is stored in the \ref axlItem with this type.
  	 *)
  	ITEM_CONTENT   := 1 shl 1,
  	(**
  	 * @brief The \ref axlItem is encapsulating an application
  	 * process instruction. Calling to \ref axl_item_get_data will
  	 * return a reference to a \ref axlPI.
  	 *
  	 *)
  	ITEM_PI        := 1 shl 2,

  	(**
  	 * @brief The \ref axlItem is encapsulating an xml
  	 * comment.
  	 *
  	 * XML comments inside Axl are handled xml node content. The
  	 * comment that is returned from the function has the initial
  	 * '<!--' and the ending '-->' elements stripped from its
  	 * body.
  	 *
  	 * You must use the convenience function \ref
  	 * axl_item_get_content to get the comment content and the
  	 * size that is stored on the \ref axlItem.
  	 *)
  	ITEM_COMMENT   := 1 shl 3,
  	(**
  	 * @brief The \ref axlItem is encapsulating an xml entity
  	 * reference that wasn't resolved yet.
  	 *
  	 * Not implemented yet.
  	 *)
  	ITEM_REF       := 1 shl 4,
  	(**
  	 * @brief The \ref axlItem is encapsulating an xml content
  	 * that was enclosed using the <![CDATA[]]> construction. This
  	 * child item works the same as \ref ITEM_CONTENT but, adding
  	 * the CDATA semantic and the fact that the content wasn't
  	 * parsed by the Axl XML engine.
  	 *
  	 * You must use the convenience function \ref
  	 * axl_item_get_content to get the CDATA content and the size
  	 * that is stored on the \ref axlItem.
  	 *
  	 *)
  	ITEM_CDATA     := 1 shl 6,

  	(**
  	 * @internal Item type which allows to signal that the item
  	 * comes from an item factory and shouldn't be deallocated in
  	 * the usual manner.
  	 *)
  	ITEM_FROM_FACTORY := 1 shl 7,
  	(**
  	 * @internal Item type which allows to signal that the content
  	 * item comes from an item factory and shouldn't be
  	 * deallocated in the usual manner.
  	 *)
  	ITEM_CONTENT_FROM_FACTORY := 1 shl 8
  );

(**
 * @brief Simple alias for the AxlDtdElementType.
 *)
//typedef AxlDtdElementType ElementType;
type
  ElementType = TAxlDtdElementType;

(**
 * @brief Axl DTD entity attribute element declaration.
 *)
type
  PaxlDtdAttr = Pointer;

(**
 * @brief Axl Processing instruction type definition.
 *)
type
  PaxlPI = Pointer;

(**
 * @brief Axl error reporting variable.
 *
 * All Axl interface report errors found, with a textual diagnostic,
 * to the application level using this variable. You have to know that
 * it is also optional, so every function that receives an \ref
 * axlError, will properly handle a NULL reference received.
 *
 * Once an error was detected, for that condition you must check the
 * documentation provided for the function that is failing, you can
 * get the error code and the error textual diagnostic by using the
 * following functions:
 *
 *  - \ref axl_error_get_code
 *  - \ref axl_error_get
 *
 * If an error is not detected, there is no especial operation to be
 * done once returned the function that has received the \ref axlError
 * error reference. However, if an error is detected, the reference
 * must be deallocated by using the following function:
 *  
 *  - \ref axl_error_free
 * 
 * Here is an example:
 * \code
 * // declare the axlError reference
 * axlError * error;
 *
 * // parse the document, giving a reference to the axlError
 * // NOTE: you can safely provide a NULL reference.
 * doc = axl_doc_parse_from_file ("test.xml", &error);
 * if (doc == NULL) {
 *     printf ("Parse error: code=%d, message=%s\n", 
 *             axl_error_get_code (error), axl_error_get (error));
 *     axl_error_free (error);
 *     return axl_false;
 * }
 *
 * // beyond this point, it is not required to do
 * // any especial task with the axlError reference
 * \endcode
 *
 * To get more information about the \ref axlError check its \ref axl_error_module "API documentation".
 *)
type
  PPaxlError = ^PaxlError;
  PaxlError = Pointer;

(**
 * @brief Axl Stream representation (an abstraction API to manage
 * source of data with convenience functions).
 *)
type
  PaxlStream = Pointer;

(**
 * @brief (DEPRECATED use \ref axl_true) Type definition to represent a boolean true value, that is equal to 1.
 *)
//#define AXL_TRUE  (axl_true) DEPRECATED

(**
 * @brief (DEPRECATED use \ref axl_false) Type definition to represent a* boolean false value, that is equal to 0.
 *)
//#define AXL_FALSE (axl_false) DEPRECATED

(**
 * @brief Alias declaration to bind the <i>int</i> to the <b>boolean</b>
 * concept (TRUE / FALSE states) (DEPRECATED).
 *
 * This is mainly used to emphasize that some integer values that
 * returns some function must be considered to be \ref axl_true or \ref
 * axl_false, that represents the boolean TRUE and FALSE values.
 *
 * This allows to perform boolean comparations using structure
 * controls like if, while, but also making a differenciation about
 * the boolean values and integer values.
 *
 * You are also allowed to use <b>bool</b> as boolean type definition.
 *)
//typedef int aboolean; DEPRECATED

(**
 * @brief Bool definition for the Axl library. This type built on top
 * of <b>int</b> is used along with \ref axl_false and \ref axl_true
 * to model those API functions and attributes that returns or receive
 * a boolean state. 
 *)
type
  Taxl_bool = longint;

(**
 * @brief Common definition to have false (\ref axl_false) value (which is defined to 0 integer value).
 *)
const
  axl_false : longint = 0;

(**
 * @brief Common definition to have true (\ref axl_true) value (which is defined to 1 integer value).
 *)
const
  axl_true : longint = 1;

(**
 * @brief Pointer to any structure definition. It should be required
 * to use this definition, however, some platforms doesn't support the
 * <b>void *</b> making it necessary to use the <b>char *</b>
 * definition as a general way to represent references.
 *)
type
  TaxlPointer = Pointer;

(**
 * @brief \ref axlList definition, a list implementation.
 * See \ref axl_list_new for more information about using this type.
 *)
type
  PaxlList = Pointer;

(**
 * @brief \ref axlListCursor definition, a iterator type used to
 * traverse an axlList in a efficient way. See \ref axl_list_cursor_get.
 *)
type
  PaxlListCursor = Pointer;

(**
 * @brief \ref axlStack definitinon, a stack implementation on top of \ref
 * axlList.
 * See \ref axl_stack_new for more information about using this type.
 *)
type
  PaxlStack = Pointer;

(**
 * @brief Compact binary state representation stack.
 *
 * This data structure allows to store binary/boolean values in an
 * efficient way.
 *
 * See \ref axl_binary_stack_new for more information.
 *)
type
  PaxlBinaryStack = Pointer;

(**
 * @brief \ref axlHash definition, a hash table to store key indexed
 * values.
 * See \ref axl_hash_new for more information about using this type.
 *)
type
  PaxlHash = Pointer;

(**
 * @brief \ref axlHashCursor definition, a support type that is used
 * to iterate a hash in a linear mode, without calling to \ref
 * axl_hash_foreach family functions (see \ref axl_hash_cursor_new).
 *)
type
  PaxlHashCursor = Pointer;

(**
 * @brief Handler definition used to compare two elements.
 * 
 * In the case they are equal, 0 is returned. In the case a should be
 * before b the -1 is returned. In the case a should be after b then 1
 * should be returned. A properly configured handler should help
 * collections and other function to order elements.
 *
 * @param a The element to compare
 * @param b The other element to compare
 * 
 * @return A value selected from {-1,0,1} according to previous
 * description.
 *)
//typedef int ( *axlEqualFunc) (axlPointer a, axlPointer b);
type
  TaxlEqualFunc = function (a:TaxlPointer; b:TaxlPointer):longint;cdecl;

(**
 * @brief Handler definition which represent deallocation functions.
 *
 * @param ptr The pointer to the memory to be released.
 *)
//typedef void ( *axlDestroyFunc) (axlPointer ptr);
type
  TaxlDestroyFunc = procedure (ptr:TaxlPointer);cdecl;

(**
 * @brief Handler used to represent the set of functions that could be
 * used to configure the axl stream allocation method. See \ref
 * axl_stream_set_buffer_alloc.
 * 
 * @param size The amount of memory to be allocated (memory requested by the axl stream).
 * 
 * @param data User defined pointer configured at \ref axl_stream_set_buffer_alloc.
 * 
 * @return The handler must return newly allocated memory to hold <b>size</b>
 * bytes.
 *)
//typedef char * ( *axlStreamAlloc) (int size, axlPointer data);
type
  TaxlStreamAlloc = function (size: longint; data: TaxlPointer):PChar;cdecl;

(**
 * @brief Handler definition for the set of functions that allows to
 * translate content into a particular format back to utf-8, which is
 * the default format used for internal data stored by Axl. 
 * 
 * @param source The source content to be decoded into utf-8. 
 *
 * @param source_size The size of the source content to be decoded.
 *
 * @param source_encoding The encoding of the source. 
 *
 * @param output The output of the decode operation. This buffer is
 * memory allocated by the caller. The size to be written is limited
 * by the following parameter.
 *
 * @param output_size The size of the output produced (in terms of
 * octects not utf-8 logical units).
 *
 * @param remain_source_index Reference where the last index of valid
 * input still pending to be process. Especially useful under
 * situation where the decode function returns 2.
 * 
 * @return The handler must return 1 if the operation was completed, 2
 * if the operation was completed but not enough size was found on
 * output buffer to store the content or 0 if the function fails.
 *)
//typedef int ( *axlStreamDecode) (const char * source, int source_size,
//                                 const char * source_encoding,
//                                 char * output, int output_size,
//                                 int * output_converted,
//                                 int * remain_source_index,
//                                 axlPointer user_data);
type
  TaxlStreamDecode = function (const source: Pchar; source_size: longint;
                               const source_encoding: Pchar;
                               output: Pchar; output_size: longint;
                               var output_converted: longint;
                               var remain_source_index: longint;
                               user_data: TaxlPointer):longint;cdecl;

(**
 * @brief A handler definition used by axl stream API to define the
 * set of functions that can be used to check content read from a file
 * into the axl stream buffer. The initial intention was to allow axl
 * babel to install an utf-8 content checked if an xml entity in utf-8
 * was detected but it allows more features.
 *
 * This handler is configured using \ref axl_stream_setup_check.
 * 
 * @param source The source to check.
 *
 * @param source_size The size of the source to check.
 *
 * @param source_encoding The source encoding found.
 *
 * @param user_data User defined pointer 
 * 
 * @return 
 *)
//typedef int ( *axlStreamContentCheck) (const char  * source,
//                                       int           source_size,
//                                       const char  * source_encoding,
//                                       axlPointer    user_data,
//                                       axlError   ** error);
type
  TaxlStreamContentCheck = function (const source         : Pchar;
                                     source_size          : longint;
                                     const source_encoding: Pchar;
                                     user_data            : TaxlPointer;
                                     error                : PPaxlError):longint;cdecl;

(**
 * @brief Axl debug levels.
 * 
 * While reporting log to the console, these levels are used to report
 * the severity for such log.
 *)
type
  TAxlDebugLevel = (
  	(**
  	 * @brief Debug level. Only used to report common
  	 * circumstances that represent the proper functionality.
  	 *)
  	AXL_LEVEL_DEBUG,
  	(**
  	 * @brief Warning level. Only used to report that an internal
  	 * issue have happend that could be interesting while
  	 * reporting error, but it could also mean common situations.
  	 *)
  	AXL_LEVEL_WARNING,
  	(**
  	 * @brief Critical level. Only used to report critical
  	 * situations where some that have happened shouldn't.
  	 *
  	 * This level should only be used while reporting critical
  	 * situations.
  	 *)
  	AXL_LEVEL_CRITICAL
  );

//axlPointer  axl_calloc(size_t count, size_t size);
function      axl_calloc(count:size_t; size:size_t):TaxlPointer;
                         cdecl;external External_library name 'axl_calloc';

//axlPointer  axl_realloc(axlPointer ref, size_t size);
function      axl_realloc(ref:TaxlPointer; size:size_t):TaxlPointer;
                          cdecl;external External_library name 'axl_realloc';

(**
 * @brief Support macro to allocate memory using axl_calloc function,
 * making a casting and using the sizeof keyword.
 *
 * @param type The type to allocate
 * @param count How many items to allocate.
 * 
 * @return A newly allocated pointer.
 *)
//#define axl_new(type, count) (type *) axl_calloc (count, sizeof (type))
//NOTE: functions have to be defined in axl_decl_imp.inc for each type to be allocated
{TODO}

//void    axl_free(axlPointer ref);
procedure axl_free(ref:TaxlPointer);cdecl;external External_library name 'axl_free';


(**
 * @brief Allows to check a condition and return if it is not meet.
 * 
 * @param expr The expresion to check.
 *)
//#define axl_return_if_fail(expr) \
//if (!(expr)) {__axl_log ("", AXL_LEVEL_CRITICAL, "Expresion '%s' have failed at %s (%s:%d)", #expr, __AXL_PRETTY_FUNCTION__, __AXL_FILE__, __AXL_LINE__); return;}
{TODO}

(**
 * @brief Allows to check a condition and return the given value if it
 * is not meet.
 * 
 * @param expr The expresion to check.
 *
 * @param val The value to return if the expression is not meet.
 *)
//#define axl_return_val_if_fail(expr, val) \
//if (!(expr)) { __axl_log ("", AXL_LEVEL_CRITICAL, "Expresion '%s' have failed, returning: %s at %s (%s:%d)", #expr, #val, __AXL_PRETTY_FUNCTION__, __AXL_FILE__, __AXL_LINE__); return val;}
{TODO}

(**
 * @brief Allows to configure how is performed the iteration other the xml document.
 *
 * An xml document could be considered as a tree structure, where the
 * root document node is the root of the tree. This enumerator allows
 * to configure how is visited each node of the tree. 
 *)
type
  TaxlIterationMode = (
  	(**
  	 * @brief Makes a deep iteration, visiting first childs of a
  	 * visited node instead of brother nodes at the same level.
  	 *)
  	DEEP_ITERATION,
  	(**
  	 * @brief Makes a wide iteration, visiting first all nodes for
  	 * a given level, after visiting nodes for the next level.
  	 *)
  	WIDE_ITERATION
  );

(**
 * \defgroup axl_handlers Axl Handlers: Handlers declarations used by Axl Library functions.
 *)

(**
 * \addtogroup axl_handlers
 * @{
 *)

(**
 * @brief Axl iteration function definition.
 *
 * This handler definition is used by \ref axl_doc_iterate as the
 * function definition that will be called for each node found in the
 * document.
 *
 * The function provides a pointer to the node found, the first
 * paramenter, and additionally, provides a pointer to the parent node
 * for the node found, the document where the node is found and an
 * optional user defined pointer provided at the function calling
 * (\ref axl_doc_iterate).
 *
 * The function returns a boolean value to signal the library to stop
 * iterating over the XML structure if \ref axl_false is returned. So, to
 * continue the iteration, you must always return \ref axl_true.
 * 
 * @param node The node found inside the document.
 *
 * @param parent The parent node for the node found (first parameter).
 *
 * @param doc The document that contains the node found.
 *
 * @param was_removed If contains a reference to a boolean value that
 * helps the invoked funtion to notify the iteration system that the
 * node was removed from the tree, using \ref axl_node_remove or \ref
 * axl_node_replace. Iteration support inside axl library is built in
 * a way that allows the programmer to remove a node (including its
 * childs) without breaking the loop, however, you must use this
 * variable to notify that the node was removed, so the iteration
 * system won't iterate over its childs.
 * 
 * @param ptr A user defined pointer that the user provided at \ref
 * axl_doc_iterate.
 * 
 * @return The callback must return axl_false in the case the iteration
 * must be stopped. Otherwise, axl_true must be returned.
 *)
//typedef axl_bool ( *axlIterationFunc) (axlNode * node, axlNode * parent, axlDoc * doc, axl_bool * was_removed, axlPointer ptr);
type
  TaxlIterationFunc = function (node:PaxlNode; parent:PaxlNode; doc:PaxlDoc; var was_removed:Taxl_bool; ptr:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Axl iteration function definition (with two user defined
 * pointer support).
 *
 * This handler definition is used by \ref axl_doc_iterate_full as the
 * function definition that will be called for each node found in the
 * document.
 *
 * The function provides a pointer to the node found, the first
 * paramenter, and additionally, provides a pointer to the parent node
 * for the node found, the document where the node is found and an
 * optional user defined pointer provided at the function calling
 * (\ref axl_doc_iterate_full).
 *
 * The function returns a axl_boolean value to signal the library to stop
 * iterating over the XML structure if \ref axl_false is returned. So, to
 * continue the iteration, you must always return \ref axl_true.
 * 
 * @param node The node found inside the document.
 *
 * @param parent The parent node for the node found (first parameter).
 *
 * @param doc The document that contains the node found.
 *
 * @param was_removed If contains a reference to a boolean value that
 * helps the invoked funtion to notify the iteration system that the
 * node was removed from the tree, using \ref axl_node_remove or \ref
 * axl_node_replace. Iteration support inside axl library is built in
 * a way that allows the programmer to remove a node (including its
 * childs) without breaking the loop, however, you must use this
 * variable to notify that the node was removed, so the iteration
 * system won't iterate over its childs.
 * 
 * @param ptr A user defined pointer that the user provided at \ref
 * axl_doc_iterate_full.
 *
 * @param ptr2 Second user defined pointer that the user provided at
 * \ref axl_doc_iterate_full.
 * 
 * @return The callback must return axl_false in the case the iteration
 * must be stopped. Otherwise, axl_true must be returned.
 *)
//typedef axl_bool ( *axlIterationFunc2) (axlNode * node, axlNode * parent, axlDoc * doc, axl_bool * was_removed, axlPointer ptr, axlPointer ptr2);
type
  TaxlIterationFunc2 = function (node:PaxlNode; parent:PaxlNode; doc:PaxlDoc; var was_removed:Taxl_bool; ptr:TaxlPointer;
                    ptr2:TaxlPointer):Taxl_bool;cdecl;
(**
 * @brief Defines a signature for a set of function that are used to
 * duplicate the content provided at the first parameter, returning a
 * copy.
 *
 * This handler definition is used by: 
 *
 * - \ref axl_list_copy
 * 
 * @param ptr The data to duplicate.
 * 
 * @return A newly allocated data duplicated.
 *)
//typedef axlPointer ( *axlDuplicateFunc) (axlPointer ptr);
type
  TaxlDuplicateFunc = function (ptr:TaxlPointer):TaxlPointer;cdecl;

(**
 * @brief Handler used by the \ref axl_list_module "axl list module"
 * to perform linear and efficient lookups.
 * 
 * @param ptr A pointer to the object stored inside the list and to be
 * checked if it is the one looked up. 
 * 
 * @param data A pointer to a user defined data that is received at
 * the lookup function and passed to this handler.
 * 
 * @return The function should return axl_true (found). Otherwise, axl_false
 * must be returned to keep on searching.
 *)
//typedef axl_bool ( *axlLookupFunc) (axlPointer ptr, axlPointer data);
type
  TaxlLookupFunc = function (ptr:TaxlPointer; data:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Hashing function used by the axl hash module to implement
 * translation from an user defined pointer into a number that should
 * be as much unique as possible.
 * 
 * @param key User defined data that represents the key for a data to
 * be stored into the hash. The value provided here usually is an
 * string but it could be any other data used as key. 
 * 
 * @return The function must return a positive value that will be used
 * to index the content into the hash table. It doesn't matter if the
 * number is greater than the table size. A modulo operation is
 * applied to the result.
 *)
//typedef unsigned int ( *axlHashFunc) (axlPointer key);
type
  TaxlHashFunc = function (key:TaxlPointer):longword;cdecl;

(**
 * @brief Foreach function signature used to represent the set of
 * functions used at \ref axl_hash_foreach.
 * 
 * The function receives the item found (key and data values) as well
 * as a user defined pointer also defined at \ref
 * axl_hash_foreach. The function must return \ref axl_true (<i>"item
 * found"</i>) to make the search to stop. In the case a full
 * iteration over all items inside the hash is required, the function
 * must always return \ref axl_false.
 * 
 * @param key The key for the item stored.
 * @param data The data associated to the key found
 * @param user_data User defined data that was provided to the axl_hash_foreach function.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlHashForeachFunc) (axlPointer key, axlPointer data, axlPointer user_data);
type
  TaxlHashForeachFunc = function (key:TaxlPointer; data:TaxlPointer; user_data:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Foreach function signature used to represent the set of
 * functions used at \ref axl_hash_foreach2.
 * 
 * The function receives the item found (key and data values) as well
 * as two user defined pointers also defined at \ref
 * axl_hash_foreach2. The function must return \ref axl_true (<i>"item
 * found"</i>) to make the search to stop. In the case a full
 * iteration over all items inside the hash is required, the function
 * must always return \ref axl_false.
 * 
 * @param key The key for the item stored.
 * @param data The data associated to the key found
 * @param user_data User defined data that was provided to the axl_hash_foreach2 function.
 * @param user_data2 Second User defined data that was provided to the axl_hash_foreach2 function.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlHashForeachFunc2) (axlPointer key, axlPointer data, axlPointer user_data, axlPointer user_data2);
type
  TaxlHashForeachFunc2 = function (key:TaxlPointer; data:TaxlPointer; user_data:TaxlPointer; user_data2:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Foreach function signature used to represent the set of
 * functions used at \ref axl_hash_foreach3.
 * 
 * The function receives the item found (key and data values) as well
 * as tree user defined pointers also defined at \ref
 * axl_hash_foreach3. The function must return \ref axl_true (<i>"item
 * found"</i>) to make the search to stop. In the case a full
 * iteration over all items inside the hash is required, the function
 * must always return \ref axl_false.
 * 
 * @param key The key for the item stored.
 *
 * @param data The data associated to the key found
 *
 * @param user_data User defined data that was provided to the
 * axl_hash_foreach3 function.
 *
 * @param user_data2 Second User defined data that was provided to the
 * axl_hash_foreach3 function.
 *
 * @param user_data3 Third User defined data that was provided to the
 * axl_hash_foreach3 function.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlHashForeachFunc3) (axlPointer key, axlPointer data, axlPointer user_data, axlPointer user_data2, axlPointer user_data3);
type
  TaxlHashForeachFunc3 = function (key:TaxlPointer; data:TaxlPointer; user_data:TaxlPointer; user_data2:TaxlPointer; user_data3:TaxlPointer):Taxl_bool;cdecl;
(**
 * @brief Foreach function signature used to represent the set of
 * functions used at \ref axl_hash_foreach4.
 * 
 * The function receives the item found (key and data values) as well
 * as tree user defined pointers also defined at \ref
 * axl_hash_foreach4. The function must return \ref axl_true (<i>"item
 * found"</i>) to make the search to stop. In the case a full
 * iteration over all items inside the hash is required, the function
 * must always return \ref axl_false.
 * 
 * @param key The key for the item stored.
 *
 * @param data The data associated to the key found
 *
 * @param user_data User defined data that was provided to the
 * axl_hash_foreach4 function.
 *
 * @param user_data2 Second User defined data that was provided to the
 * axl_hash_foreach4 function.
 *
 * @param user_data3 Third User defined data that was provided to the
 * axl_hash_foreach4 function.
 *
 * @param user_data4 Forth User defined data that was provided to the
 * axl_hash_foreach4 function.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlHashForeachFunc4) (axlPointer key, axlPointer data, axlPointer user_data, axlPointer user_data2, axlPointer user_data3, axlPointer user_data4);
type
  TaxlHashForeachFunc4 = function (key:TaxlPointer; data:TaxlPointer; user_data:TaxlPointer; user_data2:TaxlPointer; user_data3:TaxlPointer;
                    user_data4:TaxlPointer):Taxl_bool;cdecl;
(**
 * @brief Function handler definition for to allowing copying items at
 * the hash by \ref axl_hash_copy function.
 *
 * The function receive both pointers the key and the data value but,
 * only one of them must be copied. This is done to provide more
 * control at the copy process, but only the required value must be
 * returned. There is no indication to about which pointer must be
 * returned, so, don't use the same function to copy both pointers.
 *
 * The function also receive pointers to the current function
 * deallocation associated to the key and value being copied. This
 * could also work as information to know if the data must be
 * replicated or not. Having the destroy function defined for the item
 * is a clue to return an allocated item.
 * 
 * @param key The key to be copied if the function was provided to copy the key.
 *
 * @param key_destroy The key destroy function associated to the value
 * being copied.
 *
 * @param data The data to be copied if the function was provided to copy the data.
 *
 * @param data_destroy The data destroy function associated to the
 * data value being copied.
 * 
 * @return A newly allocated reference representing the copy. 
 *)
//typedef axlPointer ( *axlHashItemCopy) (axlPointer key, axlDestroyFunc key_destroy, axlPointer data, axlDestroyFunc data_destroy);
type
  TaxlHashItemCopy = function (key:TaxlPointer; key_destroy:TaxlDestroyFunc; data:TaxlPointer; data_destroy:TaxlDestroyFunc):TaxlPointer;cdecl;

(**
 * @brief Foreach function handler used at \ref axl_stack_foreach
 * function to iterate all elements inside the stack, from the head to
 * the tail.
 *
 * The function receives two user defined pointers that are defined at
 * the \ref axl_stack_foreach function. 
 * 
 * @param stack_data A reference to the stack data stored.
 *
 * @param user_data A reference to a user defined pointer passed to
 * \ref axl_stack_foreach.
 *
 * @param user_data2 A second reference to a user defined pointer
 * passed to \ref axl_stack_foreach.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlStackForeach2) (axlPointer stack_data, axlPointer user_data, axlPointer user_data2);
type
  TaxlStackForeach2 = function (stack_data:TaxlPointer; user_data:TaxlPointer; user_data2:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Foreach function handler used at \ref axl_stack_foreach3
 * function to iterate all elements inside the stack, from the head to
 * the tail.
 *
 * The function receives three user defined pointers that are defined
 * at the \ref axl_stack_foreach3 function.
 * 
 * @param stack_data A reference to the stack data stored.
 *
 * @param user_data A reference to a user defined pointer passed to
 * \ref axl_stack_foreach3.
 *
 * @param user_data2 A second reference to a user defined pointer
 * passed to \ref axl_stack_foreach3.
 *
 * @param user_data3 Third reference to a user defined pointer passed
 * to \ref axl_stack_foreach3.
 * 
 * @return \ref axl_true to make the foreach process to stop. \ref axl_false
 * to make the process to continue.
 *)
//typedef axl_bool ( * axlStackForeach3) (axlPointer stack_data, axlPointer user_data, axlPointer user_data2, axlPointer user_data3);
type
  TaxlStackForeach3 = function (stack_data:TaxlPointer; user_data:TaxlPointer; user_data2:TaxlPointer; user_data3:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Foreach function used by \ref axl_node_attr_foreach function.
 * 
 * @param key The attribute name.
 *
 * @param value The attribute value.
 *
 * @param data User defined pointer provided at \ref
 * axl_node_attr_foreach.
 *
 * @param data2 Second user defined data provided at \ref
 * axl_node_attr_foreach.
 *
 * @return The foreach function can stop the process at a particular
 * attribute by returning \ref axl_true ("item found"). To iterate all
 * attributes return \ref axl_false.
 *)
//typedef axl_bool ( * axlNodeAttrForeachFunc) (const char * key, const char * value, axlPointer data, axlPointer data2);
type
  TaxlNodeAttrForeachFunc = function (const key:Pchar; const value:Pchar; data:TaxlPointer; data2:TaxlPointer):Taxl_bool;cdecl;

(**
 * @brief Entity resolver function used by the library to translate
 * entity references into the replacement text. This is normally used
 * by the library itself, not by the application programmer.
 *
 * This handler is currently used at \ref axl_dtd_check_entity_ref_and_expand
 * 
 * @param entityName The entity name that is being requested to be
 * resolved.
 * 
 * @return The user defined data provided at \ref
 * axl_dtd_check_entity_ref_and_expand, which is passed to the
 * resolver function once it is executed.
 *)
//typedef const char * ( * axlDtdEntityResolver) (const char * entityName, axlPointer data);
type
  TaxlDtdEntityResolver = function (const entityName: PChar; data: TaxlPointer) : Pchar;cdecl;

(**
 * @brief Handler definition for the set of functions that allows to
 * detect codification found at the document being opened by the
 * \ref axlStream reference provided.
 * 
 * @param stream The stream where the detection will be implemented.
 *
 * @param detected A reference to the codification detected or NULL if
 * nothing clearly detected. For example (ascii, iso-8859) but still
 * not enough information. Handler implementator must configure an
 * static string for this value.
 *
 * @param user_data A reference to user-defined data. This value was
 * configured at \ref axl_doc_set_detect_codification_func.
 * 
 * @return axl_true if the detection was implemented properly, otherse
 * axl_false is returned. The handler could return axl_true and no
 * codification be clearly detected.
 *)
//typedef axl_bool ( * axlDocDetectCodification) (axlStream * stream, const char ** detected, axlPointer user_data, axlError ** error);
type
  TaxlDocDetectCodification = function (stream:PaxlStream; const detected:PPchar; user_data:TaxlPointer; error:PPaxlError):Taxl_bool;cdecl;
(**
 * @brief Handler definition for the set of functions that allows to
 * finally configure codification to be used for the provided stream.
 * 
 * @param stream A reference to the stream to be configured.
 *
 * @param encoding A reference to the encoding detected. It could be
 * NULL.
 *
 * @param detected_encoding A reference to the detected encoding (a
 * value provided by the \ref axlDocDetectCodification if defined).
 * 
 * @param user_data A reference to user defined data.
 *
 * @param error An optional error that will be filled in the case an
 * error is found.
 * 
 * @return axl_true if the configuration operation was done, otherwise
 * axl_false is returned.
 *)
//typedef axl_bool ( * axlDocConfigureCodification) (axlStream * stream, const char * encoding, const char * detected_encoding, axlPointer user_data, axlError ** error);
type
  TaxlDocConfigureCodification = function (stream:PaxlStream; const encoding:Pchar; const detected_encoding:Pchar; user_data:TaxlPointer; error:PPaxlError):Taxl_bool;cdecl;
(* @} *)

(* @} *)