Broken UTF-8

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Five-byte and six-byte sequences were defined in RFC 2297 but are no longer part of the UTF-8 definition.

Non-shortest forms for lowest single-byte (U+0000)

Two-byte sequence (C0 80): ��
Three-byte sequence (E0 80 80): ��
Four-byte sequence (F0 80 80 80): ��
Five-byte sequence (F8 80 80 80 80): ��
Six-byte sequence (FC 80 80 80 80 80): ��

Non-shortest forms for highest single-byte (U+007F)

Two-byte sequence (C1 BF): ��
Three-byte sequence (E0 81 BF): ��
Four-byte sequence (F0 80 81 BF): ��
Five-byte sequence (F8 80 80 81 BF): ��
Six-byte sequence (FC 80 80 80 81 BF): ��

Non-shortest forms for lowest two-byte (U+0080)

Three-byte sequence (E0 82 80): ��
Four-byte sequence (F0 80 82 80): ��
Five-byte sequence (F8 80 80 82 80): ��
Six-byte sequence (FC 80 80 80 82 80): ��

Non-shortest forms for highest two-byte (U+07FF)

Three-byte sequence (E0 9F BF): ��
Four-byte sequence (F0 80 9F BF): ��
Five-byte sequence (F8 80 80 9F BF): ��
Six-byte sequence (FC 80 80 80 9F BF): ��

Non-shortest forms for lowest three-byte (U+0800)

Four-byte sequence (F0 80 A0 80): ��
Five-byte sequence (F8 80 80 A0 80): ��
Six-byte sequence (FC 80 80 80 A0 80): ��

Non-shortest forms for highest three-byte (U+FFFF)

Four-byte sequence (F0 8F BF BF): ��
Five-byte sequence (F8 80 8F BF BF): ��
Six-byte sequence (FC 80 80 8F BF BF): ��

Non-shortest forms for lowest four-byte (U+10000)

Five-byte sequence (F8 80 90 80 80): ��
Six-byte sequence (FC 80 80 90 80 80): ��

Non-shortest forms for last Unicode (U+10FFFF)

Five-byte sequence (F8 84 8F BF BF): ��
Six-byte sequence (FC 80 84 8F BF BF): ��

Out of range

One past Unicode (F4 90 80 80): ��
Longest five-byte sequence (FB BF BF BF BF): ��
Longest six-byte sequence (FD BF BF BF BF BF): ��
First surrogate (ED A0 80): ��
Last surrogate (ED BF BF): ��
CESU-8 surrogate pair (ED A0 BD ED B2 A9): 💩

Out of range and non-shortest

One past Unicode as five-byte sequence (F8 84 90 80 80): ��
One past Unicode as six-byte sequence (FC 80 84 90 80 80): ��
First surrogate as four-byte sequence (F0 8D A0 80): ��
Last surrogate as four-byte sequence (F0 8D BF BF): ��
CESU-8 surrogate pair as two four-byte overlongs (F0 8D A0 BD F0 8D B2 A9): ��

Lone trails

One (80): �
Two (80 80): ��
Three (80 80 80): ��
Four (80 80 80 80): ��
Five (80 80 80 80 80): ��
Six (80 80 80 80 80 80): ��
Seven (80 80 80 80 80 80 80): ��
After valid two-byte (C2 B6 80): ¶�
After valid three-byte (E2 98 83 80): ☃�
After valid four-byte (F0 9F 92 A9 80): 💩�
After five-byte (FB BF BF BF BF 80): ��
After six-byte (FD BF BF BF BF BF 80): ��

Truncated sequences

Two-byte lead (C2): �
Three-byte lead (E2): �
Three-byte lead and one trail (E2 98): �
Four-byte lead (F0): �
Four-byte lead and one trail (F0 9F): �
Four-byte lead and two trails (F0 9F 92): �

Leftovers

FE (FE): �
FE and trail (FE 80): ��
FF (FF): �
FF and trail (FF 80): ��