ASCII 与 Unicode + UTF-8 [英] ASCII vs Unicode + UTF-8

问题描述

正在阅读 Joel Spolsky 关于字符编码的绝对最小值".我的理解是 ASCII 是 Code-point + Encoding 方案，在现代，我们使用 Unicode 作为 Code-point 方案，使用 UTF-8 作为 Encoding 方案.这是正确的吗?

Was reading Joel Spolsky's 'The Absolute Minimum' about character encoding. It is my understanding that ASCII is a Code-point + Encoding scheme, and in modern times, we use Unicode as the Code-point scheme and UTF-8 as the Encoding scheme. Is this correct?

推荐答案

是的，除了 UTF-8 是一种编码方案.其他编码方案包括 UTF-16(具有两种不同的字节顺序)和 UTF-32.(对于一些混淆，UTF-16 方案在 Microsoft 软件中称为Unicode".)

Yes, except that UTF-8 is an encoding scheme. Other encoding schemes include UTF-16 (with two different byte orders) and UTF-32. (For some confusion, a UTF-16 scheme is called "Unicode" in Microsoft software.)

而且，确切地说，定义 ASCII 的美国国家标准将字符集合及其编码指定为 7 位数量，但没有指定以字节为单位的特定传输编码.过去，它以不同的方式使用，例如这样五个 ASCII 字符被打包到一个 36 位存储单元中，或者 8 位字节将额外的字节用于检查目的(奇偶校验位)或传输控制.但是现在使用 ASCII，因此一个 ASCII 字符被编码为一个 8 位字节，第一位设置为零.这是事实上的标准编码方案，并隐含在大量规范中，但严格来说不是 ASCII 标准的一部分.

And, to be exact, the American National Standard that defines ASCII specifies a collection of characters and their coding as 7-bit quantities, without specifying a particular transfer encoding in terms of bytes. In the past, it was used in different ways, e.g. so that five ASCII characters were packed into one 36-bit storage unit or so that 8-bit bytes used the extra bytes for checking purposes (parity bit) or for transfer control. But nowadays ASCII is used so that one ASCII character is encoded as one 8-bit byte with the first bit set to zero. This is the de facto standard encoding scheme and implied in a large number of specifications, but strictly speaking not part of the ASCII standard.

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