Generate 8-Bit Encoding Tables

∟Chinese Text Encoding Conversion and Corruptions

∟Generate 8-Bit Encoding Tables

This section provides a tutorial example on how to generate 8-bit encoding tables with a PHP script.

Since 8-bit encodings play an important role in generating corrupted Chinese text, I decide to write a PHP script to generate the encoding table of a given encoding name.

<?php 
#- 8-Bit-Encoding-Table.php
#- Copyright (c) 2005 HerongYang.com. All Rights Reserved.
    
$encoding = $argv[1];    
$table = "   0123456789abcdef\n";
for ($i=0; $i<16; $i++) {
  $line = "";
  for ($j=0; $j<16; $j++) {
    $code = dechex($i).dechex($j);
    if ($i==0 || $i==1) $code = "00";
    $line .= $code;
  }
  $table .= dechex($i)."x ".hex2bin($line)."\n";
}
$encoded = iconv($encoding, "UTF-8//IGNORE", $table);
print($encoded);
?>

This script, 8-Bit-Encoding-Table.php, uses a nested loop to build a 8-bit byte table. The first 2 lines are kept empty to avoid control control characters. The iconv() function is used generate the final encoding table using "UTF-8" as the presentation encoding for my macOS computer.

8-Bit-Encoding-Table.php produce the output table for any encoding supported by the "iconv" command as shown below:

herong$ iconv -l | more 
ANSI_X3.4-1968 ANSI_X3.4-1986 ASCII CP367 IBM367 ISO-IR-6 ISO646-US ...
UTF-8 UTF8
UTF-8-MAC UTF8-MAC
ISO-10646-UCS-2 UCS-2 CSUNICODE
UCS-2BE UNICODE-1-1 UNICODEBIG CSUNICODE11
UCS-2LE UNICODELITTLE
ISO-10646-UCS-4 UCS-4 CSUCS4
UCS-4BE
UCS-4LE
UTF-16
UTF-16BE
UTF-16LE
UTF-32
UNICODE-1-1-UTF-7 UTF-7 CSUNICODE11UTF7
UCS-2-INTERNAL
UCS-2-SWAPPED
UCS-4-INTERNAL
UCS-4-SWAPPED
C99
CP819 IBM819 ISO-8859-1 ISO-IR-100 ISO8859-1 ISO_8859-1 ISO_8859-1:1987 ...
ECMA-118 ELOT_928 GREEK GREEK8 ISO-8859-7 ISO-IR-126 ISO8859-7 ...
ISO-8859-15 ISO-IR-203 ISO8859-15 ISO_8859-15 ISO_8859-15:1998 LATIN-9
CP1250 MS-EE WINDOWS-1250
CP1251 MS-CYRL WINDOWS-1251
CP1252 MS-ANSI WINDOWS-1252
CP1253 MS-GREEK WINDOWS-1253
CP1254 MS-TURK WINDOWS-1254
CP1255 MS-HEBR WINDOWS-1255
CP1256 MS-ARAB WINDOWS-1256
CP1257 WINBALTRIM WINDOWS-1257
CP1258 WINDOWS-1258
850 CP850 IBM850 CSPC850MULTILINGUAL
862 CP862 IBM862 CSPC862LATINHEBREW
866 CP866 IBM866 CSIBM866
...