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Added some reference comments for ldap_utf8_charlen2

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Howard Chu 2002-01-15 09:01:44 +00:00
parent e21e900392
commit 40542984cd
1 changed files with 17 additions and 2 deletions
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19
libraries/libldap/utf-8.c
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@ -70,8 +70,6 @@ int ldap_utf8_offset( const char * p )
/*
* Returns length indicated by first byte.
*
* This function should use a table lookup.
*/
const char ldap_utf8_lentab[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@ -94,6 +92,23 @@ int ldap_utf8_charlen( const char * p )
/*
* Make sure the UTF-8 char used the shortest possible encoding
* returns charlen if valid, 0 if not.
*
* Here are the valid UTF-8 encodings, taken from RFC 2279 page 4.
* The table is slightly modified from that of the RFC.
*
* UCS-4 range (hex) UTF-8 sequence (binary)
* 0000 0000-0000 007F 0.......
* 0000 0080-0000 07FF 110++++. 10......
* 0000 0800-0000 FFFF 1110++++ 10+..... 10......
* 0001 0000-001F FFFF 11110+++ 10++.... 10...... 10......
* 0020 0000-03FF FFFF 111110++ 10+++... 10...... 10...... 10......
* 0400 0000-7FFF FFFF 1111110+ 10++++.. 10...... 10...... 10...... 10......
*
* The '.' bits are "don't cares". When validating a UTF-8 sequence,
* at least one of the '+' bits must be set, otherwise the character
* should have been encoded in fewer octets. Note that in the two-octet
* case, only the first octet needs to be validated, and this is done
* in the ldap_utf8_lentab[] above.
*/
/* mask of required bits in second octet */