Character encoding
ASCII
- encoding in 7-bit.
- 32 -> 127 representing characters.
- 0 -> 31 representing control characters.
- 128 -> 255 was called OEM characters, many company has their own idea about how to use these charaters.
ANSI:
- lower 127 characters is same with ASCII.
- higher 127 characters were divided into different “code pages”
Unicode:
- Code point: In Unicode, a letter maps to something called a code point which is still just a theoretical concept.
- Encoding: Unicode Byte Order Mark: indicating encoding order is ‘high-endian’ or ‘low-endian’
UTF8: Every code point from 0-127 is stored in a single byte. Only code points 128 and above are stored using 2, 3, in fact, up to 6 bytes.
The Most Important thing:
It does not make sense to have a string without knowing what encoding it uses.