diff options
Diffstat (limited to 'utf8.h')
| -rw-r--r-- | utf8.h | 14 |
1 files changed, 11 insertions, 3 deletions
@@ -500,9 +500,17 @@ encoded as UTF-8. C<cp> is a native (ASCII or EBCDIC) code point if less than UTF_MIN_START_BYTE, UTF_MIN_ABOVE_LATIN1_BYTE - 1)) /* The largest code point representable by two UTF-8 bytes on this platform. - * As explained in the comments for __COMMON_UNI_SKIP, 32 start bytes with - * UTF_ACCUMULATION_SHIFT bits of information each */ -#define MAX_UTF8_TWO_BYTE (32 * (1U << UTF_ACCUMULATION_SHIFT) - 1) + * The binary for that code point is: + * 1101_1111 10xx_xxxx in UTF-8, and + * 1101_1111 101y_yyyy in UTF-EBCDIC I8. + * where both x and y are 1, and shown this way to indicate there is one more x + * than there is y. The number of x and y bits are their platform's respective + * UTF_CONTINUATION_BYTE_INFO_BITS. Squeezing out the bits that don't + * contribute to the value, these evaluate to: + * 1_1111 xx_xxxx in UTF-8, and + * 1_1111 y_yyyy in UTF-EBCDIC I8. + * or, the maximum value of an unsigned with (5 + info_bit_count) bits */ +#define MAX_UTF8_TWO_BYTE nBIT_UMAX(5 + UTF_CONTINUATION_BYTE_INFO_BITS) /* The largest code point representable by two UTF-8 bytes on any platform that * Perl runs on. */ |