Function xmlGetUTF8Char

ThirdParty/libxml2/vtklibxml2/xmlstring.c:857–913

* xmlGetUTF8Char: * @utf: a sequence of UTF-8 encoded bytes * @len: a pointer to the minimum number of bytes present in * the sequence. This is used to assure the next character * is completely contained within the sequence. * * Read the first UTF8 character from @utf * * Returns the char value or -1 in case of error, and sets *len to * the actual number of bytes c

 *        the actual number of bytes consumed (0 in case of error)
 */
int
xmlGetUTF8Char(const unsigned char *utf, int *len) {
    unsigned int c;

    if (utf == NULL)
        goto error;
    if (len == NULL)
        goto error;

    c = utf[0];
    if (c < 0x80) {
        if (*len < 1)
            goto error;
        /* 1-byte code */
        *len = 1;
    } else {
        if ((*len < 2) || ((utf[1] & 0xc0) != 0x80))
            goto error;
        if (c < 0xe0) {
            if (c < 0xc2)
                goto error;
            /* 2-byte code */
            *len = 2;
            c = (c & 0x1f) << 6;
            c |= utf[1] & 0x3f;
        } else {
            if ((*len < 3) || ((utf[2] & 0xc0) != 0x80))
                goto error;
            if (c < 0xf0) {
                /* 3-byte code */
                *len = 3;
                c = (c & 0xf) << 12;
                c |= (utf[1] & 0x3f) << 6;
                c |= utf[2] & 0x3f;
                if ((c < 0x800) || ((c >= 0xd800) && (c < 0xe000)))
                    goto error;
            } else {
                if ((*len < 4) || ((utf[3] & 0xc0) != 0x80))
                    goto error;
                *len = 4;
                /* 4-byte code */
                c = (c & 0x7) << 18;
                c |= (utf[1] & 0x3f) << 12;
                c |= (utf[2] & 0x3f) << 6;
                c |= utf[3] & 0x3f;
                if ((c < 0x10000) || (c >= 0x110000))
                    goto error;
            }
        }
    }
    return(c);

error:
    if (len != NULL)
	*len = 0;
    return(-1);
}