#encoding #charset


Rust library that handles OEM code pages (e.g. CP{437,737,850}) for single byte character sets

8 releases (4 stable)

2.0.0 Feb 27, 2023
2.0.0-beta.1 Feb 21, 2023
1.3.0 Feb 21, 2023
1.1.0 Mar 14, 2021
0.1.1 Aug 16, 2020

#127 in Encoding

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187 downloads per month
Used in 6 crates (3 directly)

MIT license

791 lines

Rust library for OEM Code pages

CI (master) CI (Release) oem_cp at crates.io oem_cp at docs.rs

This library handles many SBCS (single byte character sets) that are used as OEM code pages. OEM code pages are used for encoding file names in ZIP archives and characters in the terminal in Windows today.

Supported code pages

Code Page Note
437 OEM United States
720 Arabic (Transparent ASMO); Arabic (DOS)
737 OEM Greek (formerly 437G); Greek (DOS)
775 OEM Baltic; Baltic (DOS)
850 OEM Multilingual Latin 1; Western European (DOS)
852 OEM Latin 2; Central European (DOS)
855 OEM Cyrillic (primarily Russian)
857 OEM Turkish; Turkish (DOS)
858 OEM Multilingual Latin 1 + Euro symbol
860 OEM Portuguese; Portuguese (DOS)
861 OEM Icelandic; Icelandic (DOS)
862 OEM Hebrew; Hebrew (DOS)
863 OEM French Canadian; French Canadian (DOS)
864 OEM Arabic; Arabic (864)
865 OEM Nordic; Nordic (DOS)
866 OEM Russian; Cyrillic (DOS)
869 OEM Modern Greek; Greek, Modern (DOS)
874 ANSI/OEM Thai (ISO 8859-11); Thai (Windows)

Notes are quoted from https://docs.microsoft.com/en-us/windows/win32/intl/code-page-identifiers

How to use

Add oem_cp to the dependencies in Cargo.toml in your projects.

# *snip*
oem_cp = "2"
# *snip*


Use specific code pages

Encoding Unicode string to SBCS bytes

use oem_cp::{encoding_string_checked, encoding_string_lossy};
use oem_cp::code_table::{ENCODING_TABLE_CP437, ENCODING_TABLE_CP737};

assert_eq!(encode_string_checked("π≈22/7", &*ENCODING_TABLE_CP437), Some(vec![0xE3, 0xF7, 0x32, 0x32, 0x2F, 0x37]));
// Archimedes in Greek
assert_eq!(encode_string_checked("Αρχιμήδης", &*ENCODING_TABLE_CP737), Some(vec![0x80, 0xA8, 0xAE, 0xA0, 0xA3, 0xE3, 0x9B, 0x9E, 0xAA]));
// ¾ (U+00BE) is not included in CP437
assert_eq!(encoding_string_checked("½+¼=¾", &*ENCODING_TABLE_CP437), None);
// Unknown characters can be replaced with ? (0x3F)
assert_eq!(encoding_string_lossy("½+¼=¾", &*ENCODING_TABLE_CP437), vec![0xAB, 0x2B, 0xAC, 0x3D, 0x3F]);

Decoding SBCS bytes to Unicode string

use oem_cp::{decode_string_complete_table, decode_string_incomplete_table_checked, decode_string_incomplete_table_lossy};
use oem_cp::code_table::{DECODING_TABLE_CP437, DECODING_TABLE_CP874};

assert_eq!(&decode_string_complete_table(vec![0xFB, 0xAC, 0x3D, 0xAB], &DECODING_TABLE_CP437), "√¼=½");

// For encoding that has some undefined code points, you must use decode_string_incomplete_table_{checked,lossy} instead of decode_string_complete_table

// means shrimp in Thai (U+E49 => 0xE9)
assert_eq!(decode_string_incomplete_table_checked(vec![0xA1, 0xD8, 0xE9, 0xA7], &DECODING_TABLE_CP874), Some("กุ้ง".to_string()));
// 0xDB-0xDE,0xFC-0xFF is undefined in CP874 in Windows
assert_eq!(decode_string_incomplete_table_checked(vec![0x30, 0xDB], &DECODING_TABLE_CP874), None);
// You can use decode_string_incomplete_table_lossy instead
assert_eq!(&decode_string_incomplete_table_lossy(vec![0xA1, 0xD8, 0xE9, 0xA7], &DECODING_TABLE_CP874), "กุ้ง");
// Undefined code points are replaced with U+FFFD (replacement character)
assert_eq!(&decode_string_incomplete_table_lossy(vec![0x30, 0xDB], &DECODING_TABLE_CP874), "0\u{FFFD}");

Select appropriate codepage from integer

use oem_cp::{encoding_string_checked, encoding_string_lossy};

if let Some(cp874_table) = (*DECODING_TABLE_CP_MAP).get(&874) {
    assert_eq!(cp874_table.decode_string_checked(vec![0xA1, 0xD8, 0xE9, 0xA7]), Some("กุ้ง".to_string()));
    // undefined mapping 0xDB for CP874
    assert_eq!(cp874_table.decode_string_checked(vec![0xDB]), None);
    assert_eq!(&cp874_table.decode_string_lossy(vec![0xDB]), "\u{FFFD}");
} else {
    panic!("Why the hell CP874 isn't registered?");

if let Some(cp437_table) = (*ENCODING_TABLE_CP_MAP).get(&437) {
    assert_eq!(encode_string_checked("π≈22/7", cp437_table), Some(vec![0xE3, 0xF7, 0x32, 0x32, 0x2F, 0x37]));
    // ¾ is undefined in CP437
    assert_eq!(encoding_string_checked("½+¼=¾", cp437_table), None);
    // It's replaced with ? (0x3F)
    assert_eq!(encoding_string_lossy("½+¼=¾", cp437_table), vec![0xAB, 0x2B, 0xAC, 0x3D, 0x3F]);
} else {
    panic!("Why the hell CP437 isn't registered?");

Support for ANSI/EBCDIC/MBCS code pages

For ANSI (125x) and MBCS (932-950; for CJK languages) code pages, please use encoding_rs instead.

This library is only for extended ASCII encodings (0x00-0x80 must be compatible with ASCII), so EBCDIC encodings will never be supported.

Symbols from 0x01 to 0x19

This library doesn't support symbols mapped from 0x01 to 0x19 in CP437. 0x01-0x19 are mapped to U+0001-U+0019. If you prefer symbols, use codepage_437 instead.