| IBM OS/400 implements iconv in an odd way: |
| - Type iconv_t is a structure: therefore objects of this type cannot be |
| compared to (iconv_t) -1. |
| - Supported character sets names are all of the form IBMCCSIDccsid..., where |
| ccsid is a decimal 5-digit integer identifying an IBM coded character set. |
| In addition, character set names have to be given in EBCDIC. |
| Standard character set names like "UTF-8" are NOT recognized. |
| - The prototype of iconv_open() does not declare parameters as const, although |
| they are not altered. |
| |
| Since libiconv does not support EBCDIC, use of this package here as a |
| replacement is not a solution. |
| |
| For these reasons, the code in this directory implements a wrapper to the |
| OS/400 iconv implementation. The wrapper performs the following transformations: |
| - Type iconv_t is an pointer. Although OS/400 pointers are odd, comparing |
| with (iconv_t) -1 is OK. |
| - All IANA character set names are recognized in a coding- and case-insensitive |
| way, providing an equivalent CCSID exists. see |
| http://www.iana.org/assignments/character-sets/character-sets.xhtml |
| - All CCSIDs from the association file can be expressed as IBMCCSIDxxxxx where |
| xxxxx is the 5 digit CCSID; no null terminator is required. Alternate codes |
| are of the form ibm-xxx (null-terminated), where xxx is the integer CCSID with |
| leading zeroes stripped. |
| - If a IANA BIBenum is defined for a CCSID, the name iana-xxx can be used, |
| where xxx is the integer MIBenum without leading zeroes. |
| - In addition, some aliases are also taken from the association file. Examples |
| are: ASCII, EBCDIC, UTF8. |
| - Prototype of iconv_open() has const parameters. |
| - Character code names can be given in any code. |
| |
| Character set names to CCSID conversion. |
| - http://www.iana.org/assignments/character-sets/character-sets.xhtml provides |
| all IANA registered character set names and aliases associated with a |
| MIBenum, that is a unique character set identifier. |
| - A hand-maintained file ccsid_mibenum.xml associates IBM CCSIDs to |
| IANA MBenums. |
| - An OS/400 C program (in subdirectory bldcsndfa) generates a deterministic |
| finite automaton from the files mentioned above into a C file for all |
| possible character set name and associating each of them with its |
| corresponding CCSID. This program can only be run on OS/400 since it uses |
| the native iconv support for EBCDIC. |
| - Since these operations are tedious and the table generation needs bootstraping |
| with libxml2, the generated automaton is stored within sources and need not |
| be rebuilt at each compilation. However, source is provided here to allow |
| new table generation with conversion tables that were not available at the |
| time of original generation. |