Wide-char encodings
For instance an alphabet having more than 256, but less than 65536, symbols is amenable puro a two byte (00000000-00000000 onesto 11111111-11111111) encoding. Such encodings are called ”wide-char” encodings. Con spite of their being quite intuitive, wide-char encodings suffer from a number of shortcomings, that I will discuss later.
An example: UCS-2 (UTF-16)
Let us conider verso U encoding, having the following properties (I am essentially describing – save per few, minor details – the UNICODE encoding known as UCS-2).
2) U uses the first 256 codepoints sopra the same order and meaning as the Latin-1 codepage. This means that all the alphabets of the principal western european language fit mediante the first byte of this encoding.
The first problem with U us that it is spatially inefficient miglior sito di incontri per ragazze thailandesi. U containst 511 symbols encoded by sequences with at least a null byte (all the bits of the byte are niente). When U is used for texts using Western Europeans alphabets (fitting int he first byte of the encoding), every other byte is null – so basically half of the space (and of transmission time) is wasted.
Verso second problem of U relates preciso endianness. (The word comes from the inhabitants of the legendary islands oof the mythical islands of Lilliput and Blefuscu, who – as related by Swift mediante the novel ”Gulliver’s Travels” – could not agree on which end of an egg should be broken first. Lilliput’s inhabitants – by royal decree – used the largest (big endians),Blefuscu’s, who opposed the King, used the smallest (little endians). Because of this disagreement, the two peoples fought a bloody war.per ricorso su il monarca: little endians).
Even though the basic transmission uniti, for computers is the byte, the need of larger giorno units was soon felt. Among these a indivis regard is attached esatto the so called word, adjacent pair of bytes. Internally, computers often manipulates words as per whole: integer numbers, for instance, are represented by one, two or four words.
Per word, however, is never seen as basic (unsplittable). So when a word leaves the calcolatore elettronico memory it can be sent (externally represented) mediante one of two ways:
If we picture bytes as decimal digits, and given the number ”ninety-one”, we can see that big endian machine would write/memorize it as ”9” ”1”, whereas verso little endian machine would write/memorize it as ”1” ”9”.
Unbelievable (or stupid) as it may seem, for years nobody mandated the word order in external representation, so either order has been used with comparable frequency. This obviously made endianness (AKA byte-ordering) another stumbling block on the way towards pc communication. So pesky a problem, con fact, that at some point it was actually solved with verso raid operated by da Sun by deciding that, over a TCPI/IP sistema, per rete informatica byte order existed, sicuro which all computers must submit (the rete di emittenti byte order is big endian, the same that Sun machine used at the time). While that fixed for rete di emittenti communication, per niente such fix exists for files, which are still being written with different endianness on different machines.
A last problem with U is apparent sicuro programmers only. We have seen that verso U encoded character stream can contain null bytes (indeed up puro half of the bytes may be null). Traditionally though (traditionally meaning from verso 1960 until sometime around the year 2000) per null byte had verso almost universal meaning of ”end of string” for a large body of software, including programma devoted sicuro text manipulation durante Western European countries. This also means that U is not compatible with the above mentioned software, which will behave unpredictably when handed verso U-encoded string.
