Do you think 'ASCII code = A character is 8 bits'? Do you think Nike Jordan Hydro 2 a byte is a character, a character is the 8-bit? Do you still think you still think that UTF-8 is an 8-bit representation of a character? If you really think so Nike Free 3.0 V5 carefully read this article now! Why have coding? First we need to be clear that all of the data in the computer bytes are stored, processed. We need these bytes to represent the information in the computer. But these byte itself is no sense, so we need to give the real meaning of these bytes. So will develop a variety of coding standards. Coding model first need to be clear that there are two simple coding model in such a character set encoding model, a set of characters defines the character set contains what character, but how each character corresponds to a computer where the bits are also carried out definition. For instance ASCII, ASCII Lane in directly define the A - \u0026 gt; 0100 0001. Modern coding model in modern coding model in how to know a character bit maps to the computer, you need to go through the following steps. A system needs to know which characters to support the collection of these characters is called character table (Character repertoire) to the abstract character table compiled on a digital character that is the character set to map a set of integers. This mapping Air Max 2011 Womens Blue Grey is called a coded character set (CCS: Coded Character Set), unicode belongs to this layer concept, with the computer what hex ah no relationship, it is completely abstract of mathematics. The CCS in the character corresponding integer value is converted into a bit limited length, to facilitate computer use after a certain length of binary representation of the integer. This correspondence is called a character code table (CEF: Character Encoding Form) UTF-8, UTF-16 belong to this layer. CEF bit value obtained for the specifics of Nike Free 3.0 V4 Women how to store, transport in a computer. Because of the large end of the small end of the issue, which will be associated with a particular operating system. This solution is called character encoding scheme (CES: Character Encoding Scheme). Usually we said coding in the third step, when completed, are not related to the CES. So CES is not within the scope of this article. Some might wonder why now have modern coding Womens Nike Lunar model? Why do you want to split the current coding model concept out so much? 579765-700 Sonic Yellow / Sail - Cool Grey - Tour Yellow Nike Air Max LeBron 10 Low Sonic Yellow Online Like the original model of direct encoding directly stipulate good all information not? These problems in the history of 554988 316 Nike Zoom KD V Jade Pink White Sale the development of infra coding will be described. History ASCIIASCII encoded appeared on 1960s America, ASCII has defined 128 characters, use the 7 byte. These characters include the definition of the letters AZ, az, 0-9, punctuation and control symbols. Enter man ASCII in Shell, you can see the full ASCII character set. Coding model uses a simple ASCII character set, which defines the bit values a direct representation of the character. In the above-mentioned example A - \u0026 gt; 0100 0001. ASCII is directly completed the first three steps of the work of modern coding model. In English-speaking countries in the ASCII standard was perfect. But do not forget to have several thousands of languages in the world, not just for these languages these symbols ah. If you use NIKE KD 6 NSW these languages who also want to use a computer, ASCII is far from Nike Lunareclipse enough. Here coding into the chaos of the times. Chaotic times people knew a byte is eight computer can represent 256 characters. ASCII uses only seven, so it was decided to use up the remaining one also. Then the question arises, people have been prescribed a good 128 characters is no objection, but with different language needs of other characters 2015 Nike Free 5.0 who are not the same, so for the rest of the 128-character extension will be strange. And even more confusing it is that there are more characters in Asian languages system, a byte in any case can not meet demand. For example, there are more than only 100,000 Chinese characters, a 256-byte representation of how to meet it. So it has generated represent a variety of multi-byte character method (gbk is one of them), which makes the whole situation even more chaotic. (I hope to Nike Air Max see you here, no longer considered a byte is a character, a character is 8 bits). Each language has its own specific code page Mens Nike Free 3.0 Wool Skin Shoes Grey Yellow (code pages) of the situation, so that different languages appear on the same computer, different languages of people to communicate on the network have become nonsense. Then Unicode appeared. UnicodeUnicode is to give all of the characters in each computer is assigned a code. What Unicode popular is it? It is now the realization of communism, and people of all countries no longer need their own specific national identity card, but to each person a common worldwide identity. Unicode is the scope of the coded character set (CCS) of. Unicode is doing things the character table we need to represent each character is mapped to a number, this number is called the corresponding character Nike KD 7 Womens code point (code point). For example, 'Yan' word corresponding to the code point in the Unicode is U + 0x4E25. So far, we just found a bunch of mapping relationship between characters and numbers only, only to the CCS level. These figures show how to store and are not mentioned in the computer and network. Character Encoding front also belong to the concept of the character set, and now finally to the level of the CEF. In order to facilitate Nike Free 3.0 V4 Men storage and processing computing, and now what we want pure mathematics numbers correspond to the bit values of the finite length. The most intuitive design course is code point character is what numbers we put this figure into the corresponding binary representation, such as 'strict' in Unicode, the corresponding figure is 0x4E25, his binary is 100,111,000,100,101, also Yan is the word requires two bytes of storage. In this way the majority of Chinese characters can be used to represent the two bytes. But there is the presence of other languages, and maybe a character they use this method to convert it needs 4 bytes. This problem again in the end of the use of a few bytes to represent a character of it? If the provisions of two bytes, and some Air Jordan Outlet characters are represented not come out, if the provisions more bytes to represent a character, a lot of people do not agree, because some of the original language of the two-byte character handling it, what with More bytes, how much waste. Then you will think it possible to use variable-length byte to store one character do? If you use a variable-length byte represents a character, you must know a few bytes of a character, or else a computer can not be so smart. Here are some of the most commonly used UTF-8 (UTF is Unicode Transformation Format acronym) design. See below (from Ruan Yifeng's blog) x indicates bits available through the correspondence between UTF-8 can each character in the corresponding Unicode code points, converted into a binary representation of the corresponding computer. Can be found in accordance with the UTF-8 conversion is fully compatible with the original ASCII; and is represented in a multi-byte character, it means the beginning of a few 1 in accordance with the character after the UTF-8 conversion represented by several bytes. An example of the following sub-blog Ruan Yifeng known from 'strict' unicode is 4E25 (100111000100101), according to the table, it can be found in a range of 4E25 third row (0000 0800-0000 FFFF), so 'strict' UTF-8 encoding requires three bytes, that format is '1110xxxx 10xxxxxx 10xxxxxx'. Then, from the 'strict' last bit Start, fill in the form of x from back to front, the extra bits 0s. This was 'strict' UTF-8 encoding is '11100100 1,011,100,010,100,101', converted to hexadecimal is 0xE4B8A5. In addition to UTF-8 this conversion method, there is UTF-16, UTF-32 etc. conversion method. Do not introduce here. (Note that numbers represent UTF behind is the size of the symbol symbol (Code Unit) refers to the unit an encoded text that has the shortest bit combination for UTF-8, the symbol is 8 bits long.; For UTF-16, the symbol is 16 bits long. Put another way UTF-8 is based on the smallest unit of a byte, UTF-16 is the smallest unit of two bytes.) Conclusion Flowers two days finally finished, I believe we see here for character encoding have a more clear understanding of the inaccuracies in the article certainly exist, of course, we hope that criticism. E-mail: acmerfight ring gmail.com Resources Character Encoding The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) Character encoding Note: ASCII, Unicode and UTF-8 character set and character encoding Windows Notepad This of ANSI, Unicode, UTF-8 encoding of these three modes What is the difference? How to explain to non-technical staff is what Unicode character encoding and decoding of stories (ASCII, ANSI, Unicode, Utf-8)character encoding