Tcl Source Code

.PP
\fBTCL_UTF_MAX\fR is the maximum number of bytes that it takes to
represent one Unicode character in the UTF-8 representation.
.PP
\fBTcl_UniCharToUtf\fR stores the character \fIch\fR as a UTF-8 string
in starting at \fIbuf\fR.  The return value is the number of bytes stored
in \fIbuf\fR. If ch is a high surrogate (range U+D800 - U+DBFF), then
the return value will be 1 and a single byte in the range 0xF0 - 0xF4
will be stored. If you still want to produce UTF-8 output for it (even
though knowing it's an illegal code-point on its own), just call
\fBTcl_UniCharToUtf\fR again specifying ch = -1.
.PP
\fBTcl_UtfToUniChar\fR reads one UTF-8 character starting at \fIsrc\fR
and stores it as a Tcl_UniChar in \fI*chPtr\fR.  The return value is the
number of bytes read from \fIsrc\fR.  The caller must ensure that the
source buffer is long enough such that this routine does not run off the
end and dereference non-existent or random memory; if the source buffer
is known to be null-terminated, this will not happen.  If the input is

				 * required. */
{
    int gotXpg, gotSequential, value, i, flags;
    char *end;
    Tcl_UniChar ch = 0;
    int objIndex, xpgSize, nspace = numVars;
    int *nassign = TclStackAlloc(interp, nspace * sizeof(int));
    char buf[TCL_UTF_MAX + 1] = "";
    Tcl_Obj *errorMsg;		/* Place to build an error messages. Note that
				 * these are messy operations because we do
				 * not want to use the formatting engine;
				 * we're inside there! */

    /*
     * Initialize an array that records the number of times a variable is

		/* produce high surrogate, advance source pointer */
		*chPtr = 0xD800 + high;
		return 1;
	    }
#else
	    *chPtr = (((byte & 0x07) << 18) | ((src[1] & 0x3F) << 12)
		    | ((src[2] & 0x3F) << 6) | (src[3] & 0x3F));
	    if ((unsigned)(*chPtr - 0x10000) <= 0xFFFFF) {
		return 4;
	    }
#endif
	}

	/*
	 * A four-byte-character lead-byte not followed by two trail-bytes