Description:
------------
I am have made a script to parse the DMOZ RDF XML files. Which are HUGE (one is 500 MB and the other is 1.2 GB).

The major problem I've got is that the XML parser outputs some bullshit when parsing those large files!

The problem is how many bytes to read. I.e. this code:
      while ($data = fread($fp, 4096))

Now I have fixed this problem by loading the whole file into the memory:
      while ($data = fread($fp, filesize($this->xml_file)))
      {

It takes some minutes to loade the 500 MB file, but can't do that with the 1.2 GB file.

Ok, now I have searched a big deal on google. I have looked on how other parse XML files - and all I have seen use fread (including some PEAR scripts etc.)

I have also made an example which shows the code on a smaller scale. If you set fread to read 2 bytes per time - then it makes some weird output.

Reproduce code:
---------------
This example is taken from a book.
<?php 
$currentTag = ""; 

$fields = array(); 
$values = array(); 

$xml_file="data.xml"; 

function startElementHandler($parser, $name, $attributes) 
{
      global $currentTag, $table; 
      $currentTag = $name; 

      if (strtolower($currentTag) == "table") 
      {
            $table = $attributes["name"]; 
      } 

} 

function endElementHandler($parser, $name) 
{
      global $fields, $values, $count, $currentTag; 

      global $connection, $table; 

      if (strtolower($name) == "record") 
      {
            $query = "INSERT INTO $table"; 
            $query .= "(" . join(", ", $fields) . ")"; 
            $query .= " VALUES(\"" . join("\", \"", $values) . "\");"; 

          echo "$query\n";

            $fields = array(); 
            $values = array(); 
            $count = 0; 
            $currentTag = ""; 
      } 

} 

function characterDataHandler($parser, $data) 
{
      global $fields, $values, $currentTag, $count; 
      if (trim($data) != "") 
      {
            $fields[$count] = $currentTag; 

            $values[$count] = mysql_escape_string($data); 
            $count++; 
      } 
} 

$xml_parser = xml_parser_create(); 

xml_parser_set_option($xml_parser,XML_OPTION_SKIP_WHITE, TRUE); 


xml_parser_set_option($xml_parser, XML_OPTION_CASE_FOLDING, FALSE); 

xml_set_element_handler($xml_parser, "startElementHandler", "endElementHandler"); 
xml_set_character_data_handler($xml_parser, "characterDataHandler"); 

if (!($fp = fopen($xml_file, "rb"))) 
{
      die("File I/O error: $xml_file"); 
} 

while ($data = fread($fp, 2)) 
{
      if (!xml_parse($xml_parser, $data, feof($fp))) 
      {
            $ec = xml_get_error_code($xml_parser); 
            die("XML parser error (error code " . $ec . "): " . xml_error_string($ec) . 
"<br>Error occurred at line " . xml_get_current_line_number($xml_parser)); 
      } 
} 

xml_parser_free($xml_parser); 


?> 

data.xml
<?xml version="1.0"?> 
<table name="readings"> 
      <record> 
            <a>56565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656</a> 
            <b>12565656565656565656565656565656565656565656565656565656565656565622</b> 
            <c>785656565656565656565656565656565656565656565656565656565656565656.5</c> 
      </record> 
      <record> 
            <x>456565656565656565656565656565656565656565656565656565656565656565</x> 
            <y>-565656565656565656565656565656565656565656565656565656565656565610</y> 
      </record> 
      <record> 
            <x>156565656565656565656565656565656565656565656565656565656565656562</x> 
            <b>105656565656565656565656565656565656565656565656565656565656565656459</b> 
            <a>7565656565656565656565656565656565656565656565656565656565656565656</a> 
            <y>95656565656565656565656565656565656565656565656565656565656565656</y> 
      </record> 
</table>


Expected result:
----------------
INSERT INTO readings(a, b, c) VALUES("56565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656565656", "12565656565656565656565656565656565656565656565656565656565656565622", "785656565656565656565656565656565656565656565656565656565656565656.5"); INSERT INTO readings(x, y) VALUES("456565656565656565656565656565656565656565656565656565656565656565", "-565656565656565656565656565656565656565656565656565656565656565610"); INSERT INTO readings(x, b, a, y) VALUES("156565656565656565656565656565656565656565656565656565656565656562", "105656565656565656565656565656565656565656565656565656565656565656459", "7565656565656565656565656565656565656565656565656565656565656565656", "95656565656565656565656565656565656565656565656565656565656565656");


Actual result:
--------------
INSERT INTO readings(a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c, c) VALUES("56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "12", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "22", "78", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", ".5"); INSERT INTO readings(x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y) VALUES("4", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "5", "-", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "10"); INSERT INTO readings(x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, b, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, a, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y, y) VALUES("1", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "2", "1", "05", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "64", "59", "75", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "65", "6", "9", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56", "56");