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diff --git a/man/man7/utf.html b/man/man7/utf.html new file mode 100644 index 00000000..a1e767ec --- /dev/null +++ b/man/man7/utf.html @@ -0,0 +1,96 @@ +<head> +<title>utf(7) - Plan 9 from User Space</title> +<meta content="text/html; charset=utf-8" http-equiv=Content-Type> +</head> +<body bgcolor=#ffffff> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=10><td> +<tr><td width=20><td> +<tr><td width=20><td><b>UTF(7)</b><td align=right><b>UTF(7)</b> +<tr><td width=20><td colspan=2> + <br> +<p><font size=+1><b>NAME </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + UTF, Unicode, ASCII, rune – character set and format<br> + +</table> +<p><font size=+1><b>DESCRIPTION </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + The Plan 9 character set and representation are based on the Unicode + Standard and on the ISO multibyte UTF-8 encoding (Universal Character + Set Transformation Format, 8 bits wide). The Unicode Standard + represents its characters in 16 bits; UTF-8 represents such values + in an 8-bit byte stream. Throughout this + manual, UTF-8 is shortened to UTF. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + In Plan 9, a <i>rune</i> is a 16-bit quantity representing a Unicode + character. Internally, programs may store characters as runes. + However, any external manifestation of textual information, in + files or at the interface between programs, uses a machine-independent, + byte-stream encoding called UTF. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + UTF is designed so the 7-bit ASCII set (values hexadecimal 00 + to 7F), appear only as themselves in the encoding. Runes with + values above 7F appear as sequences of two or more bytes with + values only from 80 to FF. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + The UTF encoding of the Unicode Standard is backward compatible + with ASCII: programs presented only with ASCII work on Plan 9 + even if not written to deal with UTF, as do programs that deal + with uninterpreted byte streams. However, programs that perform + semantic processing on ASCII graphic characters must convert + from UTF to runes in order to work properly with non-ASCII input. + See <a href="../man3/rune.html"><i>rune</i>(3)</a>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Letting numbers be binary, a rune x is converted to a multibyte + UTF sequence as follows: + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + 01. x in [00000000.0bbbbbbb] → 0bbbbbbb<br> + 10. x in [00000bbb.bbbbbbbb] → 110bbbbb, 10bbbbbb<br> + 11. x in [bbbbbbbb.bbbbbbbb] → 1110bbbb, 10bbbbbb, 10bbbbbb<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Conversion 01 provides a one-byte sequence that spans the ASCII + character set in a compatible way. Conversions 10 and 11 represent + higher-valued characters as sequences of two or three bytes with + the high bit set. Plan 9 does not support the 4, 5, and 6 byte + sequences proposed by X-Open. When there are + multiple ways to encode a value, for example rune 0, the shortest + encoding is used. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + In the inverse mapping, any sequence except those described above + is incorrect and is converted to rune hexadecimal 0080.<br> + +</table> +<p><font size=+1><b>SEE ALSO </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <a href="../man1/ascii.html"><i>ascii</i>(1)</a>, <a href="../man1/tcs.html"><i>tcs</i>(1)</a>, <a href="../man3/rune.html"><i>rune</i>(3)</a>, <i>The Unicode Standard</i>.<br> + +</table> + +<td width=20> +<tr height=20><td> +</table> +<!-- TRAILER --> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=15><td width=10><td><td width=10> +<tr><td><td> +<center> +<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> +</center> +</table> +<!-- TRAILER --> +</body></html> |