## Unicode Unicode — Unicode and UTF-8 utility functions. |

## Synopsis

    typedef             raptor_unichar;
    int                 raptor_unicode_utf8_string_put_char (raptor_unichar c,
                                                             unsigned char *output,
                                                             size_t length);
    int                 raptor_unicode_utf8_string_get_char (const unsigned char *input,
                                                             size_t length,
                                                             raptor_unichar *output);
    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_unicode_check_utf8_string    (const unsigned char *string,
                                                             size_t length);
    int                 raptor_unicode_utf8_strlen          (const unsigned char *string,
                                                             size_t length);
    size_t              raptor_unicode_utf8_substr          (unsigned char *dest,
                                                             size_t *dest_length_p,
                                                             const unsigned char *src,
                                                             size_t src_length,
                                                             int startingLoc,
                                                             int 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_utf8_string_put_char ()

    int                 raptor_unicode_utf8_string_put_char (raptor_unichar c,
                                                             unsigned char *output,
                                                             size_t length);

Encode a Unicode character to a UTF-8 string

If `output` is NULL, then will calculate the length rather than perform the encoding. This can be used by the called to allocate space and then re-call this function with the new buffer.

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

### raptor_unicode_utf8_string_get_char ()

    int                 raptor_unicode_utf8_string_get_char (const unsigned char *input,
                                                             size_t length,
                                                             raptor_unichar *output);

Decode a UTF-8 encoded string to get 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.

`input` : | UTF-8 string buffer
`length` : | buffer size
`output` : | Pointer to the Unicode character or NULL
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

See Namespaces in XML 1.1 REC 2004-02-04 NameStartChar updating Extensible Markup Language (XML) 1.1 REC 2004-02-04 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

See Namespaces in XML REC 1999-01-14 updating Extensible Markup Language (XML) 1.0 (Third Edition) REC 2004-02-04 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

See Namespaces in XML 1.1 REC 2004-02-04 updating Extensible Markup Language (XML) 1.0 (Third Edition) REC 2004-02-04 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

See Namespaces in XML REC 1999-01-14 NCNameChar updating Extensible Markup Language (XML) 1.0 (Third Edition) REC 2004-02-04 excluding the ':'

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

### raptor_unicode_check_utf8_string ()

    int                 raptor_unicode_check_utf8_string    (const unsigned char *string,
                                                             size_t length);

Check a string is valid Unicode UTF-8.

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

### raptor_unicode_utf8_strlen ()

    int                 raptor_unicode_utf8_strlen          (const unsigned char *string,
                                                             size_t length);

Calculate the number of Unicode characters in the given UTF-8 encoded buffer

`string` : | buffer
`length` : | buffer length
Returns : | number of characters or <0 if sequence is invalid

### raptor_unicode_utf8_substr ()

    size_t              raptor_unicode_utf8_substr          (unsigned char *dest,
                                                             size_t *dest_length_p,
                                                             const unsigned char *src,
                                                             size_t src_length,
                                                             int startingLoc,
                                                             int length);

Get a unicode (UTF-8) substring of an existing UTF-8 string

If `dest` is NULL, returns the number of bytes needed to write and does no work.

`dest` : | destination string buffer to write to (or NULL)
`dest_length_p` : | location to store actual destination length (or NULL)
`src` : | source string
`src_length` : | source length in bytes
`startingLoc` : | starting location offset 0 for first Unicode character
`length` : | number of Unicode characters to copy at offset `startingLoc` (or < 0)
Returns : | number of bytes used in destination string or 0 on failure