And these numbers can either be presented with the first 8 bits as the first half of the number or the second 8 bits. Whereas in UTF-16 the situation is different because while a UInt16 number can rise to the maximum value of 65,535 it is considered by UTF-16 to be composed of two bytes (i.e.
#Textwrangler 64 bit code#
To explain, in UTF-8 code points are always understood as being read from left to right no matter how many there are. Examples of characters that consist of four code points include emoticons. Note: One code point = one byte two code points = two bytes three code points = three bytes four code points = four bytes. And because when the UTF-8 string is parsed it is known that these numbers are only used as prefixes and not standalone characters, the system will know to expect an array of bytes not a solitary one. Instead of using every number between 0 and 255 to represent a single character, and thus limiting the number of characters to 256, it uses the numbers above 193 to prefix characters composed of multiple code points (or in other words an array of UInt8 numbers): the numbers 194 to 223 prefix characters with two code points, 224 to 239 for three code points and 244 is used for characters with four code points. For this reason UTF-8 does something special. There is a problem, however, because there are more characters in the world than UInt8s can reference (remember that 255 maximum!). No matter which syntax is employed, because the unicode table tells us that a lowercase h is always represented by the number 104 then this will always be true in a unicode. While in JavaScript we can write omCharCode(104). Thanks to the unicode standard this is true in HTML where we can access a unicode value using the h syntax and in Swift where we use a syntax like this \u. If you are using UTF-8 the letter 'a' will always be equivalent to 97 and the letter 'z' to 122. So the UTF-8 standard is list of UInt8s paired with a list of characters. And the unicode system at its most basic is a list of characters that corresponds to a list of numbers. Note: If you'd like to learn more about binary numbers see here.Īn unsigned 8-bit integer (or UInt8) is the basis of the unicode UTF-8 standard. Doesn't matter how we write it (in binary, decimal, hexadecimal or even octal form), the code unit is the same, but it might help to think of each code unit (or byte) as a number between 0 and 255 for now. Now what we've done by setting all the bits in the eight bit binary number to zero is to discover the limits of an 8-bit unsigned integer, because 00000000 is its minimum value and by setting all the bits to 1 we've also discovered its maximum. So a 16-bit processor has a word size of 2 (bytes), a 32-bit processor has a word size of 4 (bytes) and a 64-bit processor has a word size of 8 (bytes). The size of the word increases as the number of bits the processor can process (in one go) increases. So a word in an 8-bit machine is equal in size to a byte. It can be written in decimal terms as 255 and in hexadecimal as FF. This is another 8-bit long number: 11111111.
It can be written in decimal terms as 0 and in hexadecimal as 0. For example, this is a binary number that is 8-bits long: 00000000. And bits are those zeroes and ones so familiar to us from popular portrayals of machine code. In an 8-bit machine each unit of data (or to give it a more exact name a word) is 8 bits long. But aside from indicating the power and sophistication of these machines what did these numbers really mean? And before 32-bit we had 16-bit computers and before that, in the days of the Commodore-64, computers were 8-bit. I'm sure that you will be familiar with a computer or device being described as 64-bit or 32-bit. So let's start with unsigned integers, bits and blog post? ) However, I was challenged to explain my knowledge and so I will attempt to do so. There is a difference between understanding something and being able to explain it.
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