UTF-8 is a variable-width character encoding used for electronic communication. Formulated to encode all 1,112,064 valid character code points in Unicode using one to four one-byte (8-bit) code units, UTF-8 has become the dominant character encoding for the World Wide Web, accounting for more than 90% of all web pages.
Key Features of UTF-8
Compatibility with ASCII: UTF-8 is backward compatible with ASCII. ASCII characters only require one byte in UTF-8, which simplifies handling ASCII texts.
Self-synchronization: The design of UTF-8 allows the start of any character in the byte sequence to be recognized without requiring backward scanning. This makes it easier to recover from partial or incorrect transmissions.
Byte order independence: Unlike UTF-16 and UTF-32, UTF-8 does not require byte order marking (BOM), thus avoiding the complications of endianess.
Efficient use of space: UTF-8 uses only as much space as needed per character, ranging from 1 to 4 bytes, making it space-efficient for texts containing primarily ASCII characters.
UTF-8 Encoding Mechanism
UTF-8 encodes characters using a series of bytes where each byte contains a group of bits that represent the character. Here’s how characters are represented:
1-byte characters: Standard ASCII, 0-127 (0x00-0x7F), occupy a single byte, preserving the full ASCII table.
2-byte characters: Needed for characters from Latin-derived alphabets, Greek, Cyrillic, Coptic, Armenian, Hebrew, and Arabic scripts.
3-byte characters: Basic Multilingual Plane (BMP), including most common characters and symbols.
4-byte characters: Rarely used characters from the Supplementary Planes, which include historic scripts, musical notation, mathematical symbols, etc.
Example of Encoding
The character € (Euro sign) is encoded in UTF-8 as three bytes:
0xE2 0x82 0xAC
Common Uses of UTF-8
Web development: As the default encoding for HTML5 and other web standards.
File encoding: Preferred encoding for text files in open-source and modern applications.
Databases: Often used for storing text to support a diverse set of languages and characters.
Advantages of UTF-8
Universal support: UTF-8 can represent any character in the Unicode standard, making it suitable for globalized environments.
Optimized performance: Generally requires less space than UTF-16 for texts primarily in ASCII, which is common for most programming languages and protocols.
Widely adopted: Supported across most platforms, programming languages, and applications, enhancing interoperability.