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| Unicode units |
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Fundamentals - Unicode units These Unicode units provide common functions needed to use Unicode strings in your Delphi application. The following units make up the collection:
Using Unicode in your Delphi application Unicode Encodings Unicode consists of tens of thousands of characters, each of which has an unique code. To be able to store any Unicode characters you'll need 4 bytes (a 32-bit value) for every characters. This encoding of Unicode is called UCS4. To simplify matters, Unicode defines allmost all commonly used characters in the first 65536 characters. This means that most Unicode strings can be encoded using 2 bytes (a 16-bit value) for every character. This encoding is called UCS2, which in Delphi is represented using WideChar and WideString. To simplify matters further, Unicode defines the first 128 characters to be identical to the characters from ASCII. An encoding that makes use of this fact is UTF-8. UTF-8 is a variable length encoding with several propeties that makes it ideal for storing Unicode when the majority of characters are ASCII characters. Among the properties of UTF-8 is:
Which encoding to use? When you expect to work with lots of international text, use WideChar and WideString. You should note that WideStrings are not reference counted on Windows. This makes them less effiecient to use than LongStrings. When you expect to work with text which is mostly ASCII, but which may contain the occasional international text, use UTF8Strings. They use less memory and are reference counted in Delphi. How the Fundamentals Unicode library helps you The functions in cUnicodeCodecs allow you to convert various legacy characters sets (such as ISO-8859-1 which is the default for HTML pages, ASCII and cyrillic encodings) to Unicode, which can be stored as either WideStrings or UTF-8 Strings. Once you have Unicode Strings, you can use the string functions in cUnicode to work with the Unicode strings. Unicode links The Unicode consortium Official site of the Unicode consortium. Here you will find the latest technical documents and data on Unicode. Unicode Transformation Formats (UTF) Detailed information on the UTF encodings. Unicode in XML and other Markup Languages Technical guidelines on the use of Unicode in conjunction with markup languages such as XML. Zvon Character Search Allows you to search the Unicode character database online. |