From d26c49657db909ccfa4434bdc975a3278db749fc Mon Sep 17 00:00:00 2001 From: duerst Date: Sun, 26 Oct 2014 02:24:28 +0000 Subject: string.c: improved comment. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48142 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- string.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'string.c') diff --git a/string.c b/string.c index b433a21446..d9b5c7d601 100644 --- a/string.c +++ b/string.c @@ -1187,26 +1187,27 @@ rb_str_init(int argc, VALUE *argv, VALUE str) /* * UTF-8 leading bytes have either 0xxxxxxx or 11xxxxxx * bit representation. (see http://en.wikipedia.org/wiki/UTF-8) - * Therefore, following pseudo code can detect UTF-8 leading byte. + * Therefore, the following pseudocode can detect UTF-8 leading bytes. * * if (!(byte & 0x80)) * byte |= 0x40; // turn on bit6 - * return ((byte>>6) & 1); // bit6 represent it's leading byte or not. + * return ((byte>>6) & 1); // bit6 represent whether this byte is leading or not. * - * This function calculate every bytes in the argument word `s' - * using the above logic concurrently. and gather every bytes result. + * This function calculates whether a byte is leading or not for all bytes + * in the argument word by concurrently using the above logic, and then + * adds up the number of leading bytes in the word. */ static inline uintptr_t count_utf8_lead_bytes_with_word(const uintptr_t *s) { uintptr_t d = *s; - /* Transform into bit0 represent UTF-8 leading or not. */ + /* Transform so that bit0 indicates whether we have a UTF-8 leading byte or not. */ d |= ~(d>>1); d >>= 6; d &= NONASCII_MASK >> 7; - /* Gather every bytes. */ + /* Gather all bytes. */ d += (d>>8); d += (d>>16); #if SIZEOF_VOIDP == 8 -- cgit v1.2.3