Unicode

## Unicode Unicode — Unicode utility functions. |

## Synopsis

    typedef             librdf_unichar;
    int                 librdf_unicode_char_to_utf8         (librdf_unichar c,
                                                             unsigned char *output,
                                                             int length);
    int                 librdf_utf8_to_unicode_char         (librdf_unichar *output,
                                                             const unsigned char *input,
                                                             int length);
    unsigned char *     librdf_utf8_to_latin1               (const unsigned char *input,
                                                             int length,
                                                             int *output_length);
    unsigned char *     librdf_utf8_to_latin1_2             (const unsigned char *input,
                                                             size_t length,
                                                             unsigned char discard,
                                                             size_t *output_length);
    unsigned char *     librdf_latin1_to_utf8               (const unsigned char *input,
                                                             int length,
                                                             int *output_length);
    unsigned char *     librdf_latin1_to_utf8_2             (const unsigned char *input,
                                                             size_t length,
                                                             size_t *output_length);
    void                librdf_utf8_print                   (const unsigned char *input,
                                                             int length,
                                                             FILE *stream);

## Description

Utility functions to convert between UTF-8, full Unicode and Latin-1. Redland uses UTF-8 for all string formats (except where noted) but these may need to be converted to other Unicode encodings or downgraded with loss to Latin-1.

## Details

### librdf_unichar

    typedef raptor_unichar librdf_unichar;

Unicode codepoint.

### librdf_unicode_char_to_utf8 ()

    int                 librdf_unicode_char_to_utf8         (librdf_unichar c,
                                                             unsigned char *output,
                                                             int length);

Convert a Unicode character to UTF-8 encoding.

`deprecated`: Use `raptor_unicode_utf8_string_put_char()` noting that the length argument is a size_t.

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

`c` : | Unicode character
`output` : | UTF-8 string buffer or NULL
`length` : | buffer size (will be truncated to size_t)
Returns : | bytes written to output buffer or <0 on failure

### librdf_utf8_to_unicode_char ()

    int                 librdf_utf8_to_unicode_char         (librdf_unichar *output,
                                                             const unsigned char *input,
                                                             int length);

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

`deprecated`: Use `raptor_unicode_utf8_string_get_char()` noting that the arg order has changed to input, length (a size_t), output.

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 (will be truncated to size_t)
Returns : | bytes used from input buffer or <0 on failure

### librdf_utf8_to_latin1 ()

    unsigned char *     librdf_utf8_to_latin1               (const unsigned char *input,
                                                             int length,
                                                             int *output_length);

Convert a UTF-8 string to ISO Latin-1.

Converts the given UTF-8 string to the ISO Latin-1 subset of Unicode (characters 0x00-0xff), discarding any out of range characters.

`deprecated` for `librdf_utf8_to_latin1_2()` that takes and returns size_t sizes and allows replacing of out of range characters.

If `output_length` is not NULL, the returned string length will be stored there.

`input` : | UTF-8 string buffer
`length` : | buffer size (will be truncated to size_t)
`output_length` : | Pointer to variable to store resulting string length or NULL
Returns : | pointer to new ISO Latin-1 string or NULL on failure

### librdf_utf8_to_latin1_2 ()

    unsigned char *     librdf_utf8_to_latin1_2             (const unsigned char *input,
                                                             size_t length,
                                                             unsigned char discard,
                                                             size_t *output_length);

Convert a UTF-8 string to ISO Latin-1.

Converts the given UTF-8 string to the ISO Latin-1 subset of Unicode (characters 0x00-0xff). Out of range characters are replaced with `discard` unless it is NUL (\0).

If `output_length` is not NULL, the returned string length will be stored there.

`input` : | UTF-8 string buffer
`length` : | buffer size
`discard` : | character to use to replace out of range characters or NUL (\0) to discard
`output_length` : | Pointer to variable to store resulting string length or NULL
Returns : | pointer to new ISO Latin-1 string or NULL on failure

### librdf_latin1_to_utf8 ()

    unsigned char *     librdf_latin1_to_utf8               (const unsigned char *input,
                                                             int length,
                                                             int *output_length);

Convert an ISO Latin-1 encoded string to UTF-8.

Converts the given ISO Latin-1 string to an UTF-8 encoded string representing the same content. This is lossless.

`deprecated` for `librdf_latin1_to_utf8_2()` that takes and returns size_t sizes.

If `output_length` is not NULL, the returned string length will be stored there.

`input` : | ISO Latin-1 string buffer
`length` : | buffer size (will be truncated to size_t)
`output_length` : | Pointer to variable to store resulting string length or NULL
Returns : | pointer to new UTF-8 string or NULL on failure

### librdf_latin1_to_utf8_2 ()

    unsigned char *     librdf_latin1_to_utf8_2             (const unsigned char *input,
                                                             size_t length,
                                                             size_t *output_length);

Convert an ISO Latin-1 encoded string to UTF-8.

Converts the given ISO Latin-1 string to an UTF-8 encoded string representing the same content. This is lossless.

If `output_length` is not NULL, the returned string length will be stored there.

`input` : | ISO Latin-1 string buffer
`length` : | buffer size
`output_length` : | Pointer to variable to store resulting string length or NULL
Returns : | pointer to new UTF-8 string or NULL on failure

### librdf_utf8_print ()

    void                librdf_utf8_print                   (const unsigned char *input,
                                                             int length,
                                                             FILE *stream);

Print a UTF-8 string to a stream.

Pretty prints the UTF-8 string in a pseudo-C character format like \uhex digits when the characters fail the `isprint()` test.

`input` : | UTF-8 string buffer
`length` : | buffer size (will be truncated to size_t)
`stream` : | FILE* stream