NAME

       scan_utf8 - decode an unsigned integer from UTF-8 encoding

SYNTAX

       #include <libowfat/scan.h>

       size_t scan_utf8(const char *src,size_t len,uint32_t *dest);

       size_t scan_utf8_sem(const char *src,size_t len,uint32_t *dest);

DESCRIPTION

       scan_utf8  decodes  an  unsigned  integer  in  UTF-8 encoding from a memory area holding binary data.  It
       writes the decode value in dest and returns the number of bytes it read from src.

       scan_utf8 never reads more than len bytes from src.  If the sequence is longer than that, or  the  memory
       area contains an invalid sequence, scan_utf8 returns 0 and does not touch dest.

       The length of the longest valid UTF-8 sequence is 6.

       scan_utf8  will  reject syntactically invalid encodings, but not semantically invalid ones. scan_utf8_sem
       will additionally reject surrogates.

NOTE

       fmt_utf8 and scan_utf8 implement the encoding from UTF-8, but are meant to be able to store integers, not
       just Unicode code points.  Values above 0x10ffff are not valid UTF-8.  If you are using this function  to
       parse UTF-8, you need to reject them (see RFC 3629).

SEE ALSO

       fmt_utf8(3), scan_utf8_sem(3)

                                                                                                    scan_utf8(3)