## Unicode

Unicode — Unicode and UTF-8 utility functions.

## Synopsis

    typedef             raptor_unichar;
    int                 raptor_unicode_char_to_utf8         (raptor_unichar c,
                                                             unsigned char *output);
    int                 raptor_utf8_to_unicode_char         (raptor_unichar *output,
                                                             unsigned char *input,
                                                             int length);
    int                 raptor_unicode_is_xml11_namestartchar
                                                            (raptor_unichar c);
    int                 raptor_unicode_is_xml10_namestartchar
                                                            (raptor_unichar c);
    int                 raptor_unicode_is_xml11_namechar    (raptor_unichar c);
    int                 raptor_unicode_is_xml10_namechar    (raptor_unichar c);
    int                 raptor_utf8_check                   (unsigned char *string,
                                                             size_t length);

## Description

Functions to support converting to and from Unicode written in UTF-8 which is the native internal string format of all the redland libraries. Includes checking for Unicode names using either the XML 1.0 or XML 1.1 rules.

## Details

### raptor_unichar

    typedef unsigned long raptor_unichar;

raptor Unicode codepoint

### raptor_unicode_char_to_utf8 ()

    int                 raptor_unicode_char_to_utf8         (raptor_unichar c,
                                                             unsigned char *output);

Convert a Unicode character to UTF-8 encoding.

Based on `librdf_unicode_char_to_utf8()` with no need to calculate length since the encoded character is always copied into a buffer with sufficient size.

`c` : | Unicode character
`output` : | UTF-8 string buffer or NULL
Returns : | bytes encoded to output buffer or <0 on failure

### raptor_utf8_to_unicode_char ()

    int                 raptor_utf8_to_unicode_char         (raptor_unichar *output,
                                                             unsigned char *input,
                                                             int length);

Convert an UTF-8 encoded buffer to a Unicode character.

If output is NULL, then will calculate the number of bytes that will be used from the input buffer and not perform the conversion.

`output` : | Pointer to the Unicode character or NULL
`input` : | UTF-8 string buffer
`length` : | buffer size
Returns : | bytes used from input buffer or <0 on failure: -1 input buffer too short or length error, -2 overlong UTF-8 sequence, -3 illegal code positions, -4 code out of range U+0000 to U+10FFFF. In cases -2, -3 and -4 the coded character is stored in the output.

### raptor_unicode_is_xml11_namestartchar ()

    int                 raptor_unicode_is_xml11_namestartchar
                                                            (raptor_unichar c);

Check if Unicode character is legal to start an XML 1.1 Name

Namespaces in XML 1.1 REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml11-20040204/NT-NameStartChar updating Extensible Markup Language (XML) 1.1 REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml11-20040204/ sec 2.3, [4a] excluding the ':'

`c` : | Unicode character to check
Returns : | non-0 if legal

### raptor_unicode_is_xml10_namestartchar ()

    int                 raptor_unicode_is_xml10_namestartchar
                                                            (raptor_unichar c);

Check if Unicode character is legal to start an XML 1.0 Name

Namespaces in XML REC 1999-01-14 http://www.w3.org/TR/1999/REC-xml-names-19990114/NT-NCName updating Extensible Markup Language (XML) 1.0 (Third Edition) REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml-20040204/ excluding the ':'

`c` : | Unicode character to check
Returns : | non-0 if legal

### raptor_unicode_is_xml11_namechar ()

    int                 raptor_unicode_is_xml11_namechar    (raptor_unichar c);

Check if a Unicode codepoint is a legal to continue an XML 1.1 Name

Namespaces in XML 1.1 REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml11-20040204/ updating Extensible Markup Language (XML) 1.1 REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml11-20040204/ sec 2.3, [4a] excluding the ':'

`c` : | Unicode character
Returns : | non-0 if legal

### raptor_unicode_is_xml10_namechar ()

    int                 raptor_unicode_is_xml10_namechar    (raptor_unichar c);

Check if a Unicode codepoint is a legal to continue an XML 1.0 Name

Namespaces in XML REC 1999-01-14 http://www.w3.org/TR/1999/REC-xml-names-19990114/NT-NCNameChar updating Extensible Markup Language (XML) 1.0 (Third Edition) REC 2004-02-04 http://www.w3.org/TR/2004/REC-xml-20040204/ excluding the ':'

`c` : | Unicode character
Returns : | non-0 if legal

### raptor_utf8_check ()

    int                 raptor_utf8_check                   (unsigned char *string,
                                                             size_t length);

Check a string is UTF-8.

`string` : | UTF-8 string
`length` : | length of string
Returns : | Non 0 if the string is UTF-8