mirror of
https://github.com/koreader/koreader
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d6c81f5097
* Simple News (RSS/Atom) downloader plugin * Limit news from sources * new News Downloader menu entry - goto news dir * Initial configuration logic * Download each feed source to separate folder * 2 feed sources in example config
484 lines
17 KiB
Lua
484 lines
17 KiB
Lua
---
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-- Overview:
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-- =========
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--
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-- This module provides a non-validating XML stream parser in Lua.
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--
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-- Features:
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-- =========
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--
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-- * Tokenises well-formed XML (relatively robustly)
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-- * Flexible handler based event API (see below)
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-- * Parses all XML Infoset elements - ie.
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-- - Tags
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-- - Text
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-- - Comments
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-- - CDATA
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-- - XML Decl
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-- - Processing Instructions
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-- - DOCTYPE declarations
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-- * Provides limited well-formedness checking
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-- (checks for basic syntax & balanced tags only)
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-- * Flexible whitespace handling (selectable)
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-- * Entity Handling (selectable)
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--
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-- Limitations:
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-- ============
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--
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-- * Non-validating
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-- * No charset handling
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-- * No namespace support
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-- * Shallow well-formedness checking only (fails
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-- to detect most semantic errors)
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--
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-- API:
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-- ====
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--
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-- The parser provides a partially object-oriented API with
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-- functionality split into tokeniser and handler components.
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--
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-- The handler instance is passed to the tokeniser and receives
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-- callbacks for each XML element processed (if a suitable handler
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-- function is defined). The API is conceptually similar to the
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-- SAX API but implemented differently.
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--
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-- The following events are generated by the tokeniser
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--
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-- handler:start - Start Tag
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-- handler:end - End Tag
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-- handler:text - Text
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-- handler:decl - XML Declaration
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-- handler:pi - Processing Instruction
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-- handler:comment - Comment
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-- handler:dtd - DOCTYPE definition
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-- handler:cdata - CDATA
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--
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-- The function prototype for all the callback functions is
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--
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-- callback(val,attrs,start,end)
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--
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-- where attrs is a table and val/attrs are overloaded for
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-- specific callbacks - ie.
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--
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-- Callback val attrs (table)
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-- -------- --- -------------
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-- start name { attributes (name=val).. }
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-- end name nil
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-- text <text> nil
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-- cdata <text> nil
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-- decl "xml" { attributes (name=val).. }
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-- pi pi name { attributes (if present)..
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-- _text = <PI Text>
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-- }
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-- comment <text> nil
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-- dtd root element { _root = <Root Element>,
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-- _type = SYSTEM|PUBLIC,
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-- _name = <name>,
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-- _uri = <uri>,
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-- _internal = <internal dtd>
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-- }
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--
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-- (start & end provide the character positions of the start/end
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-- of the element)
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--
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-- XML data is passed to the parser instance through the 'parse'
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-- method (Note: must be passed a single string currently)
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--
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-- Options
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-- =======
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--
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-- Parser options are controlled through the 'self.options' table.
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-- Available options are -
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--
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-- * stripWS
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--
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-- Strip non-significant whitespace (leading/trailing)
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-- and do not generate events for empty text elements
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--
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-- * expandEntities
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--
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-- Expand entities (standard entities + single char
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-- numeric entities only currently - could be extended
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-- at runtime if suitable DTD parser added elements
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-- to table (see obj._ENTITIES). May also be possible
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-- to expand multibyre entities for UTF-8 only
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--
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-- * errorHandler
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--
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-- Custom error handler function
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--
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-- NOTE: Boolean options must be set to 'nil' not '0'
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--
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-- Usage
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-- =====
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--
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-- Create a handler instance -
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--
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-- h = { start = function(t,a,s,e) .... end,
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-- end = function(t,a,s,e) .... end,
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-- text = function(t,a,s,e) .... end,
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-- cdata = text }
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--
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-- (or use predefined handler - see handler.lua)
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--
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-- Create parser instance -
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--
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-- p = xmlParser(h)
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--
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-- Set options -
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--
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-- p.options.xxxx = nil
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--
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-- Parse XML data -
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--
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-- xmlParser:parse("<?xml... ")
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-- License:
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-- ========
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--
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-- This code is freely distributable under the terms of the Lua license
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-- (http://www.lua.org/copyright.html)
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--
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-- History
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-- =======
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-- Added parameter parseAttributes (boolean) in xmlParser.parse method
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-- If true (default value), tag attributtes are parsed.
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-- by Manoel Campos da Silva Filho
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-- http://manoelcampos.com
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-- http://about.me/manoelcampos
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--
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-- $Id: xml.lua,v 1.1.1.1 2001/11/28 06:11:33 paulc Exp $
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--
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-- $Log: xml.lua,v $
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-- Revision 1.1.1.1 2001/11/28 06:11:33 paulc
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-- Initial Import
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--
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--@author Paul Chakravarti (paulc@passtheaardvark.com)<p/>
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---Parses a XML string
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--@param handler Handler object to be used to convert the XML string
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--to another formats. @see handler.lua
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local xmlParser = function(handler)
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local obj = {}
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-- Public attributes
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obj.options = {
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stripWS = 1,
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expandEntities = 1,
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errorHandler = function(err,pos)
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error(string.format("%s [char=%d]\n",
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err or "Parse Error",pos))
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end,
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}
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-- Public methods
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obj.parse = function(self, str, parseAttributes)
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if parseAttributes == nil then
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parseAttributes = true
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end
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self._handler.parseAttributes = parseAttributes
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local match,endmatch,pos = 0,0,1
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local text,endt1,endt2,tagstr,tagname,attrs,starttext,endtext
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local errstart,errend,extstart,extend
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while match do
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-- Get next tag (first pass - fix exceptions below)
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match,endmatch,text,endt1,tagstr,endt2 = string.find(str,self._XML,pos)
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if not match then
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if string.find(str, self._WS,pos) then
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-- No more text - check document complete
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if #self._stack ~= 0 then
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self:_err(self._errstr.incompleteXmlErr,pos)
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else
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break
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end
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else
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-- Unparsable text
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self:_err(self._errstr.xmlErr,pos)
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end
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end
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-- Handle leading text
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starttext = match
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endtext = match + string.len(text) - 1
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match = match + string.len(text)
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text = self:_parseEntities(self:_stripWS(text))
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if text ~= "" and self._handler.text then
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self._handler:text(text,nil,match,endtext)
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end
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-- Test for tag type
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if string.find(string.sub(tagstr,1,5),"?xml%s") then
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-- XML Declaration
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match,endmatch,text = string.find(str,self._PI,pos)
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if not match then
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self:_err(self._errstr.declErr,pos)
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end
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if match ~= 1 then
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-- Must be at start of doc if present
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self:_err(self._errstr.declStartErr,pos)
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end
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tagname,attrs = self:_parseTag(text)
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-- TODO: Check attributes are valid
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-- Check for version (mandatory)
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if attrs.version == nil then
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self:_err(self._errstr.declAttrErr,pos)
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end
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if self._handler.decl then
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self._handler:decl(tagname,attrs,match,endmatch)
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end
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elseif string.sub(tagstr,1,1) == "?" then
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-- Processing Instruction
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match,endmatch,text = string.find(str,self._PI,pos)
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if not match then
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self:_err(self._errstr.piErr,pos)
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end
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if self._handler.pi then
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-- Parse PI attributes & text
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tagname,attrs = self:_parseTag(text)
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local pi = string.sub(text,string.len(tagname)+1)
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if pi ~= "" then
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if attrs then
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attrs._text = pi
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else
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attrs = { _text = pi }
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end
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end
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self._handler:pi(tagname,attrs,match,endmatch)
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end
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elseif string.sub(tagstr,1,3) == "!--" then
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-- Comment
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match,endmatch,text = string.find(str,self._COMMENT,pos)
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if not match then
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self:_err(self._errstr.commentErr,pos)
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end
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if self._handler.comment then
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text = self:_parseEntities(self:_stripWS(text))
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self._handler:comment(text,next,match,endmatch)
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end
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elseif string.sub(tagstr,1,8) == "!DOCTYPE" then
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-- DTD
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match,endmatch,attrs = self:_parseDTD(string,pos)
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if not match then
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self:_err(self._errstr.dtdErr,pos)
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end
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if self._handler.dtd then
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self._handler:dtd(attrs._root,attrs,match,endmatch)
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end
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elseif string.sub(tagstr,1,8) == "![CDATA[" then
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-- CDATA
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match,endmatch,text = string.find(str,self._CDATA,pos)
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if not match then
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self:_err(self._errstr.cdataErr,pos)
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end
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if self._handler.cdata then
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self._handler:cdata(text,nil,match,endmatch)
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end
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else
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-- Normal tag
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-- Need check for embedded '>' in attribute value and extend
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-- match recursively if necessary eg. <tag attr="123>456">
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while 1 do
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errstart,errend = string.find(tagstr,self._ATTRERR1)
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if errend == nil then
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errstart,errend = string.find(tagstr,self._ATTRERR2)
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if errend == nil then
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break
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end
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end
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extstart,extend,endt2 = string.find(str,self._TAGEXT,endmatch+1)
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tagstr = tagstr .. string.sub(string,endmatch,extend-1)
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if not match then
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self:_err(self._errstr.xmlErr,pos)
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end
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endmatch = extend
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end
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-- Extract tagname/attrs
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tagname,attrs = self:_parseTag(tagstr)
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if (endt1=="/") then
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-- End tag
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if self._handler.endtag then
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if attrs then
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-- Shouldnt have any attributes in endtag
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self:_err(string.format("%s (/%s)",
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self._errstr.endTagErr,
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tagname)
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,pos)
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end
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if table.remove(self._stack) ~= tagname then
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self:_err(string.format("%s (/%s)",
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self._errstr.unmatchedTagErr,
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tagname)
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,pos)
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end
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self._handler:endtag(tagname,nil,match,endmatch)
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end
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else
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-- Start Tag
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table.insert(self._stack,tagname)
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if self._handler.starttag then
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self._handler:starttag(tagname,attrs,match,endmatch)
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end
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--TODO: Tags com fechamento automático estão sendo
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--retornadas como uma tabela, o que complica
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--para a app NCLua tratar isso. É preciso
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--fazer com que seja retornado um campo string vazio.
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-- Self-Closing Tag
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if (endt2=="/") then
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table.remove(self._stack)
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if self._handler.endtag then
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self._handler:endtag(tagname,nil,match,endmatch)
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end
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end
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end
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end
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pos = endmatch + 1
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end
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end
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-- Private attribures/functions
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obj._handler = handler
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obj._stack = {}
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obj._XML = '^([^<]*)<(%/?)([^>]-)(%/?)>'
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obj._ATTR1 = '([%w-:_]+)%s*=%s*"(.-)"'
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obj._ATTR2 = '([%w-:_]+)%s*=%s*\'(.-)\''
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obj._CDATA = '<%!%[CDATA%[(.-)%]%]>'
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obj._PI = '<%?(.-)%?>'
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obj._COMMENT = '<!%-%-(.-)%-%->'
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obj._TAG = '^(.-)%s.*'
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obj._LEADINGWS = '^%s+'
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obj._TRAILINGWS = '%s+$'
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obj._WS = '^%s*$'
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obj._DTD1 = '<!DOCTYPE%s+(.-)%s+(SYSTEM)%s+["\'](.-)["\']%s*(%b[])%s*>'
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obj._DTD2 = '<!DOCTYPE%s+(.-)%s+(PUBLIC)%s+["\'](.-)["\']%s+["\'](.-)["\']%s*(%b[])%s*>'
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obj._DTD3 = '<!DOCTYPE%s+(.-)%s*(%b[])%s*>'
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obj._DTD4 = '<!DOCTYPE%s+(.-)%s+(SYSTEM)%s+["\'](.-)["\']%s*>'
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obj._DTD5 = '<!DOCTYPE%s+(.-)%s+(PUBLIC)%s+["\'](.-)["\']%s+["\'](.-)["\']%s*>'
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obj._ATTRERR1 = '=%s*"[^"]*$'
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obj._ATTRERR2 = '=%s*\'[^\']*$'
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obj._TAGEXT = '(%/?)>'
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obj._ENTITIES = { ["<"] = "<",
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[">"] = ">",
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["&"] = "&",
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["""] = '"',
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["'"] = "'",
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["&#(%d+);"] = function (x)
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local d = tonumber(x)
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if d >= 0 and d < 256 then
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return string.char(d)
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else
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return "&#"..d..";"
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end
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end,
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["&#x(%x+);"] = function (x)
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local d = tonumber(x,16)
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if d >= 0 and d < 256 then
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return string.char(d)
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else
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return "&#x"..x..";"
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end
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end,
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}
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obj._err = function(self,err,pos)
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if self.options.errorHandler then
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self.options.errorHandler(err,pos)
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end
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end
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obj._errstr = { xmlErr = "Error Parsing XML",
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declErr = "Error Parsing XMLDecl",
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declStartErr = "XMLDecl not at start of document",
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declAttrErr = "Invalid XMLDecl attributes",
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piErr = "Error Parsing Processing Instruction",
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commentErr = "Error Parsing Comment",
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cdataErr = "Error Parsing CDATA",
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dtdErr = "Error Parsing DTD",
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endTagErr = "End Tag Attributes Invalid",
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unmatchedTagErr = "Unbalanced Tag",
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incompleteXmlErr = "Incomplete XML Document",
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}
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obj._stripWS = function(self,s)
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if self.options.stripWS then
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s = string.gsub(s,'^%s+','')
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s = string.gsub(s,'%s+$','')
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end
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return s
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end
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obj._parseEntities = function(self,s)
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if self.options.expandEntities then
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--for k,v in self._ENTITIES do
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for k,v in pairs(self._ENTITIES) do
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--print (k, v)
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s = string.gsub(s,k,v)
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end
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end
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return s
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end
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obj._parseDTD = function(self,s,pos)
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-- match,endmatch,root,type,name,uri,internal
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local m,e,r,t,n,u,i
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m,e,r,t,u,i = string.find(s,self._DTD1,pos)
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if m then
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return m,e,{_root=r,_type=t,_uri=u,_internal=i}
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end
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m,e,r,t,n,u,i = string.find(s,self._DTD2,pos)
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if m then
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return m,e,{_root=r,_type=t,_name=n,_uri=u,_internal=i}
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end
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m,e,r,i = string.find(s,self._DTD3,pos)
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if m then
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return m,e,{_root=r,_internal=i}
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end
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m,e,r,t,u = string.find(s,self._DTD4,pos)
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if m then
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return m,e,{_root=r,_type=t,_uri=u}
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end
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m,e,r,t,n,u = string.find(s,self._DTD5,pos)
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if m then
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return m,e,{_root=r,_type=t,_name=n,_uri=u}
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end
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return nil
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end
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---Parses a string representing a tag
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--@param s String containing tag text
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--@return Returns a string containing the tagname and a table attrs
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--containing the atributtes of tag
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obj._parseTag = function(self,s)
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local attrs = {}
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local tagname = string.gsub(s,self._TAG,'%1')
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string.gsub(s,self._ATTR1,function (k,v)
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attrs[string.lower(k)]=self:_parseEntities(v)
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attrs._ = 1
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end)
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string.gsub(s,self._ATTR2,function (k,v)
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attrs[string.lower(k)]=self:_parseEntities(v)
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attrs._ = 1
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end)
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if attrs._ then
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attrs._ = nil
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else
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attrs = nil
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end
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return tagname,attrs
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end
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return obj
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end
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return { xmlParser = xmlParser }
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