diff options
| -rw-r--r-- | generic/tclUtf.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/generic/tclUtf.c b/generic/tclUtf.c index 845690c..6ed169e 100644 --- a/generic/tclUtf.c +++ b/generic/tclUtf.c @@ -182,8 +182,8 @@ Invalid( * * Tcl_UniCharToUtf -- * - * Stores the given Tcl_UniChar as a sequence of UTF-8 bytes in the - * provided buffer. Equivalent to Plan 9 runetochar(). + * Stores the given Tcl_UniChar as a sequence of UTF-8 bytes in the provided + * buffer. Equivalent to Plan 9 runetochar(). * * Surrogate pairs are handled as follows: When ch is a high surrogate, * the first byte of the 4-byte UTF-8 sequence is stored in the buffer and @@ -191,10 +191,9 @@ Invalid( * surrogate and the same buffer, the remaining 3 bytes of the 4-byte * UTF-8 sequence are produced. * - * If no low surrogate follows the high surrogate (which is actually - * illegal), this can be handled reasonably by calling Tcl_UniCharToUtf - * again with ch = -1. This produces a 3-byte UTF-8 sequence - * representing the high surrogate. + * If no low surrogate follows the high surrogate (which is actually illegal), + * calling Tcl_UniCharToUtf again with ch being -1 produces a 3-byte UTF-8 + * sequence representing the high surrogate. * * Results: * Returns the number of bytes stored into the buffer. @@ -208,12 +207,13 @@ Invalid( #undef Tcl_UniCharToUtf size_t Tcl_UniCharToUtf( - int ch, /* The Tcl_UniChar to be stored in the - * buffer. Can be or'ed with flag TCL_COMBINE */ - char *buf) /* Buffer in which the UTF-8 representation of - * the Tcl_UniChar is stored. Buffer must be - * large enough to hold the UTF-8 character - * (at most 4 bytes). */ + int ch, /* The Tcl_UniChar to be stored in the + * buffer. Can be or'ed with flag TCL_COMBINE + */ + char *buf) /* Buffer in which the UTF-8 representation of + * ch is stored. Must be large enough to hold the UTF-8 + * character (at most 4 bytes). + */ { #if TCL_UTF_MAX > 3 int flags = ch; @@ -250,7 +250,12 @@ Tcl_UniCharToUtf( /* Previous Tcl_UniChar was not a high surrogate, so just output */ } else { /* High surrogate */ + + /* Add 0x10000 to the raw number encoded in the surrogate + * pair in order to get the code point. + */ ch += 0x40; + /* Fill buffer with specific 3-byte (invalid) byte combination, so following low surrogate can recognize it and combine */ buf[2] = (char) ((ch << 4) & 0x30); |