为什么Utf8与ASCII兼容 [英] Why Utf8 is compatible with ascii

问题描述

A是U+0041 LATIN CAPITAL LETTER A. ASCII中的A是065.

A in UTF-8 is U+0041 LATIN CAPITAL LETTER A. A in ASCII is 065.

UTF-8如何与ASCII向后兼容?

How is UTF-8 is backwards-compatible with ASCII?

推荐答案

ASCII仅使用8位字节的前7位.因此，从00000000到01111111的所有组合.此范围内的所有128个字节都映射到一个特定字符.

ASCII uses only the first 7 bits of an 8 bit byte. So all combinations from 00000000 to 01111111. All 128 bytes in this range are mapped to a specific character.

UTF-8保留这些确切的映射.在ASCII中用01101011表示的字符在UTF-8中也用相同的字节表示.所有其他字符均按多个字节的顺序进行编码，其中每个字节的最高位均设置为1.也就是说，UTF-8中所有非ASCII字符的每个字节的格式均为1xxxxxxx.

UTF-8 keep these exact mappings. The character represented by 01101011 in ASCII is also represented by the same byte in UTF-8. All other characters are encoded in sequences of multiple bytes in which each byte has the highest bit set; i.e. every byte of all non-ASCII characters in UTF-8 is of the form 1xxxxxxx.

这篇关于为什么Utf8与ASCII兼容的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！