Bit Message
The Bit Message is a message that is hidden within the lines of an octet stream and it is represented as a hexadecimal string which has maximum length of 149 octets. The first 9 octets of the message contain the header for the message and the rest comprise the content. The header contains 1 type octet, 7 timestamp octets, and 1 message length octet. The content contains a maximum of 140 octets and could be packed with either 7 bit, 8 bit or 16 bit. 7 bit packed messages have a length of 160 characters, 8 bit packed messages have a length of 140 characters, and 16 bit packed messages will only have a length of 70 characters.
Here are some details on the structure of a bit message:
| BIT MESSAGE FORMAT | ||||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
| Octet-nth | ||||||||||
| HEADER | TYPE | |||||||||
| YEAR | ||||||||||
| MONTH | ||||||||||
| DAY | ||||||||||
| HOUR | ||||||||||
| MINUTE | ||||||||||
| SECOND | ||||||||||
| TIMEZONE | ||||||||||
| LENGTH | ||||||||||
| CONTENT | Octet-1 | |||||||||
| ... |
... |
|||||||||
| Octet-140 | ||||||||||
| 7-BIT PACKED MESSAGE | ||||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
| Octet-nth | ||||||||||
| 1 | 0 | b6 | b5 | b4 | b3 | b2 | b1 | b0 | ||
| 8-BIT PACKED MESSAGE | ||||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
| Octet-nth | ||||||||||
| 1 | b7 | b6 | b5 | b4 | b3 | b2 | b1 | b0 | ||
| 16-BIT PACKED MESSAGE | ||||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
| Octet-nth | ||||||||||
| 1 | b7 | b6 | b5 | b4 | b3 | b2 | b1 | b0 | ||
| 2 | b15 | b14 | b13 | b12 | b11 | b10 | b9 | b8 | ||
| HEADER | # OCTET | DESCRIPTION | |||||
| TYPE | 1 | contains specific flag for specific format identifier | |||||
| DETAIL | |||||||
| Bit 0-1 : | reserved message class meaning | ||||||
| Bit 2-3 : | message encoding | ||||||
| Bit 3 | Bit 2 | Pack | |||||
| 0 | 0 | 7 bit | |||||
| 0 | 1 | 8 bit | |||||
| 1 | 0 | 16 bit | |||||
| 1 | 1 | reserved | |||||
| Bit 4 : | reserved flag message class meaning | ||||||
| Bit 5 : | reserved message is compressed or uncompressed | ||||||
| Bit 6-7 : | reserved general data coding | ||||||
| TIMESTAMP | 7 | contains specific swapped nibbles for specific format identifier | |||||
| DETAIL | |||||||
| Octet 1 | YEARe.g. 10 for 2001 | ||||||
| Octet 2 | MONTHe.g. 10 for Jan | ||||||
| Octet 3 | DAYe.g. 10 for 01 | ||||||
| Octet 4 | HOURe.g. 10 for 01 | ||||||
| Octet 5 | MINUTEe.g. 10 for 01 | ||||||
| Octet 6 | SECONDe.g. 10 for 01 | ||||||
| Octet 7 | TIMEZONEe.g. 80 for 08 x 15 / 60 = +2 | ||||||
| The Time Zone is GMT format, expressed in quarters of an hour. In the first of the two semi-octets, the first bit represents the algebraic sign of this difference (0 : positive, 1 : negative) | |||||||
| LENGTH | 1 | maximum characters allowed is 160, 140 or 70 characters depends on message packed format | |||||
Input data: A hexadecimal string that is a bit message (unicode).
Output data: A list containing the timestamp, length of message and the message itself. The message is unicode.
Example:
assert(checkio('002080629173148007EDF27C1E3E9701') ==
['26 Aug 2002 19:37:41 GMT +2', 7, 'message']), "First Test"
assert(checkio('00317050201171820FD3323BDC0ED341C4303DEC3E8700') ==
['05 Jul 2013 02:11:17 GMT +7', 15, u'Selamat Datang!']), "Second Test, 7 bit"
assert(checkio('000130925161956915C8729E054A82C26D50DA0D7296EFA0EC5BBE06') ==
['29 Mar 2010 15:16:59 GMT -4', 21, 'Hey, I am in New York']), "Third Test, negative timezone"
assert(checkio('08071010101010611F04180441043A043B044E04470435043D043804350020043F043E04340442043204350440043604340430043504420020043F0440043004320438043B043E') ==
['01 Jan 1970 01:01:01 GMT +4', 31, 'Исключение подтверждает правило']), "Fourth Test, simulate 32-bit signed integer real life problem"
assert(checkio('088310913041804C23805E4E0D82E5805E4E4B002C805E4E4B4E0D82E5898B4E4B002C898B4E4B4E0D82E577E54E4B002C77E54E4B4E0D82E5884C4E4B002C5B7881F365BC884C4E4B800C6B6277E3 ') ==
['19 Jan 2038 03:14:08 GMT -11', 35, '聞不若聞之,聞之不若見之,見之不若知之,知之不若行之,學至於行之而止矣']), "But, we pass Y2K38 problem"
How it is used:
