xml.lua

module(..., package.seeall)

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--
-- xml.lua - XML parser for use with the Corona SDK.
--
-- version: 1.0
--
-- NOTE: This is a modified version of Alexander Makeev's Lua-only XML parser
-- found here: http://lua-users.org/wiki/LuaXml
--
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function newParser()
	
	local DEBUG = false
	
	XmlParser = {};

	function XmlParser:ToXmlString(value)
	  value = string.gsub (value, "&", "&");    -- '&' -> "&"
	  value = string.gsub (value, "<", "&lt;");    -- '<' -> "&lt;"
	  value = string.gsub (value, ">", "&gt;");    -- '>' -> "&gt;"
	  --value = string.gsub (value, "'", "&apos;");  -- '\'' -> "&apos;"
	  value = string.gsub (value, "\"", "&quot;");  -- '"' -> "&quot;"
	  -- replace non printable char -> "&#xD;"
		 value = string.gsub(value, "([^%w%&%;%p%\t% ])",
			 function (c) 
			   return string.format("&#x%X;", string.byte(c)) 
			   --return string.format("&#x%02X;", string.byte(c)) 
			   --return string.format("&#%02d;", string.byte(c)) 
			 end);
	  return value;
	end
	
	function XmlParser:FromXmlString(value)  
		value = string.gsub(value, "&#x([%x]+)%;",
			function(h) 
			  return string.char(tonumber(h,16)) 
			end);
		value = string.gsub(value, "&#([0-9]+)%;",
			function(h)
			  	--
				-- hack to deal with UTF-8 entities
				-- 
				if h == "8217" or h == "8216" or h == "8218" then return "'" end
				if h == "8211" then return "-" end
				if h == "8212" then return "--" end
				if h == "8230" then return "..." end
				if h == "8220" or h == "8221" or h == "8222" then return "\"" end
				if h == "8214" then return "(tm)" end
				if h == "8226" then return "." end
				if tonumber(h) >= 1000 then return "" end
			  	return string.char(tonumber(h,10)) 
			end);
	  value = string.gsub (value, "&quot;", "\"");
	  value = string.gsub (value, "&apos;", "'");
	  value = string.gsub (value, "&gt;", ">");
	  value = string.gsub (value, "&lt;", "<");
	  value = string.gsub (value, "&amp;", "&");
	  return value;
	end
	   
	function XmlParser:ParseArgs(s)
	  local arg = {}
	  string.gsub(s, "(%w+)=([\"'])(.-)%2", function (w, _, a)
		  arg[w] = self:FromXmlString(a);
		end)
	  return arg
	end
	
	function log(...)
	  if DEBUG then
		print("XmlParser: ", unpack(arg))
	  end
	end
	
	function XmlParser:ParseXmlText(xmlText)    
	  local stack = {}
	  local top = {name=nil,value=nil,properties={},child={}}
	  table.insert(stack, top)
	  local ni,c,label,xarg, empty,cdata_end,cdata_end2,abs
	  local i, j = 1, 1
	  while true do      
		ni,j,c,label,xarg, empty = 
		  xmlText:find("<(%/?)([%w:]+)(.-)(%/?)>", i)                        
		if not ni then break end    
		
		local text = string.sub(xmlText, i, ni-1);         
		
		local cdata_start,cdata_start2 = text:find("<!%[CDATA%[")        
		if (cdata_start) then
		  abs = i+cdata_start2       
		  log("Found CDATA start tag", abs)        
		  cdata_end,cdata_end2 = xmlText:find("%]%]>",i)
		  log("Found CDATA end tag", cdata_end2)      
		  i = cdata_end2+1
		else 
		  i = j+1
		end
		
		if not cdata_start and not string.find(text, "^%s*$") then -- skip white space           
		  top.value=(top.value or "")..self:FromXmlString(text);      
		end
		
		if cdata_start then -- CDATA 
		  top.value = (top.value or "")..xmlText:sub(abs,cdata_end-2)
		elseif empty == "/" then  -- empty element tag
		  table.insert(top.child, {name=label,value=nil,properties=self:ParseArgs(xarg),child={}})
		elseif c == "" then   -- start tag
		  top = {name=label, value=nil, properties=self:ParseArgs(xarg), child={}}
		  table.insert(stack, top)   -- new level
		  log("openTag ="..top.name);
		else  -- end tag
		  local toclose = table.remove(stack)  -- remove top
		  log("closeTag="..toclose.name);
		  top = stack[#stack]
		  if #stack < 1 then
			error("XmlParser: nothing to close with "..label)
		  end
		  if toclose.name ~= label then        
			error("XmlParser: trying to close <"..toclose.name.."> with <"..label..">")
		  end
		  table.insert(top.child, toclose)
		end  
		
	  end
	  local text = string.sub(xmlText, i);
	  if not string.find(text, "^%s*$") then
		  stack[#stack].value=(stack[#stack].value or "")..self:FromXmlString(text);
	  end
	  if #stack > 1 then
		error("XmlParser: unclosed "..stack[stack.n].name)
	  end  
	  
	  --local xml_obj = XmlObject(stack[1].child[1])
	  
	  return stack[1].child[1];
	end
	
	function XmlParser:loadFile(xmlFilename, base)
		if not base then
			base = system.ResourceDirectory
		end
			
		local path = system.pathForFile( xmlFilename, base )
		local hFile, err = io.open(path,"r");
		
		if hFile and not err then
			local xmlText=hFile:read("*a"); -- read file content
			io.close(hFile);
			return self:ParseXmlText(xmlText),nil;
		else
			print( err )
			return nil
		end
	end
	
	return XmlParser
end