Wide-char encodings

For instance an alphabet having more than 256, but less than 65536, symbols is amenable onesto verso two byte (00000000-00000000 esatto 11111111-11111111) encoding. Such encodings are called „wide-char“ encodings. Sopra spite of their being quite intuitive, wide-char encodings suffer from per number of shortcomings, that I will discuss later.

An example: UCS-2 (UTF-16)

Let us conider per U encoding, having the following properties (I am essentially describing – save a few, minor details – the UNICODE encoding known as UCS-2).

2) U uses the first 256 codepoints per the same order and meaning as the Latin-1 codepage. This means that all the alphabets of the principal western european language fit in the first byte of this encoding.

The first problem with U us that it is spatially inefficient. U containst 511 symbols encoded by sequences with at least verso null byte (all the bits of the byte are nulla). 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.

A 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 durante 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 verso bloody war.per reazione riguardo a il maesta: little endians).

Even though the basic transmission uniti, for computers is the byte, the need of larger scadenza units was soon felt. Among these a indivis regard is attached puro 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.

A word, however, is never seen as basic (unsplittable). So when per word leaves the cervello elettronico memory it can be sent (externally represented) durante 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 con 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 calcolatore elettronico communication. So pesky a problem, sopra fact https://worldbrides.org/it/orchidromance-recensione/, that at some point it was actually solved with verso attacco operated by da Sun by deciding that, over verso TCPI/IP sistema, a rete di emittenti byte order existed, sicuro which all computers must submit (the rete informatica byte order is big endian, the same that Sun machine used at the time). While that fixed for rete informatica communication, niente affatto such fix exists for files, which are still being written with different endianness on different machines.

Verso last problem with U is apparent to programmers only. We have seen that per U encoded character stream can contain null bytes (indeed up onesto half of the bytes may be null). Traditionally though (traditionally meaning from contro 1960 until sometime around the year 2000) a null byte had verso almost universal meaning of „end of string“ for per large body of programma, including programma devoted sicuro text manipulation con Western European countries. This also means that U is not compatible with the above mentioned software, which will behave unpredictably when handed per U-encoded string.