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* string.c (count_utf8_lead_bytes_with_word): wrote function

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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@30778 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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kosaki 2011-02-03 16:54:52 +00:00
parent b0d216c818
commit aa36d4df21
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ChangeLog
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@ -1,3 +1,8 @@
Fri Feb 4 01:50:13 2011 KOSAKI Motohiro <kosaki.motohiro@gmail.com>
* string.c (count_utf8_lead_bytes_with_word): wrote function
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Fri Feb 4 00:14:55 2011 Nobuyoshi Nakada <nobu@ruby-lang.org>
* ext/zlib/zlib.c (gzfile_reader_get_unused): no need to dup

17
string.c
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@ -1038,13 +1038,30 @@ rb_enc_strlen_cr(const char *p, const char *e, rb_encoding *enc, int *cr)
#ifdef NONASCII_MASK
#define is_utf8_lead_byte(c) (((c)&0xC0) != 0x80)
/*
* UTF-8 leading bytes have either 0xxxxxxx or 11xxxxxx
* bit represention. (see http://en.wikipedia.org/wiki/UTF-8)
* Therefore, following pseudo code can detect UTF-8 leading byte.
*
* if (!(byte & 0x80))
* byte |= 0x40; // turn on bit6
* return ((byte>>6) & 1); // bit6 represent it's leading byte or not.
*
* This function calculate every bytes in the argument word `s'
* using the above logic concurrently. and gather every bytes result.
*/
static inline VALUE
count_utf8_lead_bytes_with_word(const VALUE *s)
{
VALUE d = *s;
/* Transform into bit0 represent UTF-8 leading or not. */
d |= ~(d>>1);
d >>= 6;
d &= NONASCII_MASK >> 7;
/* Gather every bytes. */
d += (d>>8);
d += (d>>16);
#if SIZEOF_VALUE == 8