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Utf(3)			    Tcl	Library	Procedures			Utf(3)

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NAME
       Tcl_UniChar,   Tcl_UniCharToUtf,	 Tcl_UtfToUniChar,  Tcl_UniCharToUtfD-
       String,	 Tcl_UtfToUniCharDString,   Tcl_UniCharLen,   Tcl_UniCharNcmp,
       Tcl_UniCharNcasecmp,   Tcl_UniCharCaseMatch,   Tcl_UtfNcmp,   Tcl_UtfN-
       casecmp,	  Tcl_UtfCharComplete,	 Tcl_NumUtfChars,    Tcl_UtfFindFirst,
       Tcl_UtfFindLast,	 Tcl_UtfNext, Tcl_UtfPrev, Tcl_UniCharAtIndex, Tcl_Ut-
       fAtIndex, Tcl_UtfBackslash - routines for manipulating UTF-8 strings

SYNOPSIS
       #include	<tcl.h>

       typedef ... Tcl_UniChar;

       int
       Tcl_UniCharToUtf(ch, buf)

       int
       Tcl_UtfToUniChar(src, chPtr)

       char *
       Tcl_UniCharToUtfDString(uniStr, uniLength, dsPtr)

       Tcl_UniChar *
       Tcl_UtfToUniCharDString(src, length, dsPtr)

       int
       Tcl_UniCharLen(uniStr)

       int
       Tcl_UniCharNcmp(ucs, uct, numChars)

       int
       Tcl_UniCharNcasecmp(ucs,	uct, numChars)

       int
       Tcl_UniCharCaseMatch(uniStr, uniPattern,	nocase)

       int
       Tcl_UtfNcmp(cs, ct, numChars)

       int
       Tcl_UtfNcasecmp(cs, ct, numChars)

       int
       Tcl_UtfCharComplete(src,	length)

       int
       Tcl_NumUtfChars(src, length)

       const char *
       Tcl_UtfFindFirst(src, ch)

       const char *
       Tcl_UtfFindLast(src, ch)

       const char *
       Tcl_UtfNext(src)

       const char *
       Tcl_UtfPrev(src,	start)

       Tcl_UniChar
       Tcl_UniCharAtIndex(src, index)

       const char *
       Tcl_UtfAtIndex(src, index)

       int
       Tcl_UtfBackslash(src, readPtr, dst)

ARGUMENTS
       char *buf (out)				   Buffer in which  the	 UTF-8
						   representation    of	   the
						   Tcl_UniChar is stored.   At
						   most	 TCL_UTF_MAX bytes are
						   stored in the buffer.

       int ch (in)				   The Unicode character to be
						   converted or	examined.

       Tcl_UniChar *chPtr (out)			   Filled with the Tcl_UniChar
						   represented by the head  of
						   the UTF-8 string.

       const char *src (in)			   Pointer to a	UTF-8 string.

       const char *cs (in)			   Pointer to a	UTF-8 string.

       const char *ct (in)			   Pointer to a	UTF-8 string.

       const Tcl_UniChar *uniStr (in)		   A  null-terminated  Unicode
						   string.

       const Tcl_UniChar *ucs (in)		   A  null-terminated  Unicode
						   string.

       const Tcl_UniChar *uct (in)		   A  null-terminated  Unicode
						   string.

       const Tcl_UniChar *uniPattern (in)	   A  null-terminated  Unicode
						   string.

       int length (in)				   The	length	of  the	 UTF-8
						   string in bytes (not	 UTF-8
						   characters).	  If negative,
						   all bytes up	to  the	 first
						   null	byte are used.

       int uniLength (in)			   The	length	of the Unicode
						   string in characters.  Must
						   be greater than or equal to
						   0.

       Tcl_DString *dsPtr (in/out)		   A pointer to	 a  previously
						   initialized Tcl_DString.

       unsigned	long numChars (in)		   The number of characters to
						   compare.

       const char *start (in)			   Pointer to the beginning of
						   a UTF-8 string.

       int index (in)				   The	index  of  a character
						   (not	 byte)	in  the	 UTF-8
						   string.

       int *readPtr (out)			   If  non-NULL,  filled  with
						   the number of bytes in  the
						   backslash sequence, includ-
						   ing the  backslash  charac-
						   ter.

       char *dst (out)				   Buffer  in  which the bytes
						   represented	by  the	 back-
						   slash  sequence are stored.
						   At most  TCL_UTF_MAX	 bytes
						   are stored in the buffer.

       int nocase (in)				   Specifies whether the match
						   should be done  case-sensi-
						   tive	 (0)  or case-insensi-
						   tive	(1).
______________________________________________________________________________

DESCRIPTION
       These routines convert  between	UTF-8  strings	and  Tcl_UniChars.   A
       Tcl_UniChar  is	a Unicode character represented	as an unsigned,	fixed-
       size quantity.  A UTF-8 character is a Unicode character	represented as
       a  varying-length  sequence  of	up  to TCL_UTF_MAX bytes.  A multibyte
       UTF-8 sequence consists of a lead byte followed by some number of trail
       bytes.

       TCL_UTF_MAX  is	the maximum number of bytes that it takes to represent
       one Unicode character in	the UTF-8 representation.

       Tcl_UniCharToUtf	stores the Tcl_UniChar ch as a UTF-8 string in	start-
       ing at buf.  The	return value is	the number of bytes stored in buf.

       Tcl_UtfToUniChar	 reads	one UTF-8 character starting at	src and	stores
       it as a Tcl_UniChar in *chPtr.  The return value	is the number of bytes
       read  from  src.	 The caller must ensure	that the source	buffer is long
       enough such that	this routine does not run off the end and  dereference
       non-existent  or	 random	 memory;  if  the source buffer	is known to be
       null-terminated,	this will not happen.  If the input is not  in	proper
       UTF-8 format, Tcl_UtfToUniChar will store the first byte	of src in *ch-
       Ptr as a	Tcl_UniChar between 0x80 and 0xFF and return 1.

       Tcl_UniCharToUtfDString converts	the given  Unicode  string  to	UTF-8,
       storing	the  result in a previously initialized	Tcl_DString.  You must
       specify uniLength, the length of	the given Unicode string.  The	return
       value  is  a pointer to the UTF-8 representation	of the Unicode string.
       Storage for the return value is appended	to the end of the Tcl_DString.

       Tcl_UtfToUniCharDString converts	the given  UTF-8  string  to  Unicode,
       storing	the  result in the previously initialized Tcl_DString.	In the
       argument	length,	you may	either specify the length of the  given	 UTF-8
       string  in  bytes  or  "-1", in which case Tcl_UtfToUniCharDString uses
       strlen to calculate the length.	The return value is a pointer  to  the
       Unicode	representation	of  the	 UTF-8 string.	Storage	for the	return
       value is	appended to the	end of the Tcl_DString.	 The Unicode string is
       terminated with a Unicode null character.

       Tcl_UniCharLen  corresponds  to	strlen for Unicode characters.	It ac-
       cepts a null-terminated Unicode string and returns the number  of  Uni-
       code characters (not bytes) in that string.

       Tcl_UniCharNcmp and Tcl_UniCharNcasecmp correspond to strncmp and strn-
       casecmp,	respectively, for Unicode characters.  They accept  two	 null-
       terminated  Unicode  strings  and  the number of	characters to compare.
       Both strings are	assumed	to  be	at  least  numChars  characters	 long.
       Tcl_UniCharNcmp	 compares  the	two strings character-by-character ac-
       cording to the Unicode  character  ordering.   It  returns  an  integer
       greater	than,  equal to, or less than 0	if the first string is greater
       than,  equal  to,  or  less  than  the  second	string	 respectively.
       Tcl_UniCharNcasecmp is the Unicode case insensitive version.

       Tcl_UniCharCaseMatch  is	the Unicode equivalent to Tcl_StringCaseMatch.
       It accepts a null-terminated Unicode string, a Unicode pattern,	and  a
       boolean value specifying	whether	the match should be case sensitive and
       returns whether the string matches the pattern.

       Tcl_UtfNcmp corresponds to strncmp for UTF-8 strings.  It  accepts  two
       null-terminated	UTF-8 strings and the number of	characters to compare.
       (Both strings are assumed to be at  least  numChars  characters	long.)
       Tcl_UtfNcmp  compares  the two strings character-by-character according
       to the Unicode character	ordering.  It returns an integer greater than,
       equal to, or less than 0	if the first string is greater than, equal to,
       or less than the	second string respectively.

       Tcl_UtfNcasecmp corresponds to strncasecmp for UTF-8  strings.	It  is
       similar	to  Tcl_UtfNcmp	 except	comparisons ignore differences in case
       when comparing upper, lower or title case characters.

       Tcl_UtfCharComplete returns 1 if	the source UTF-8 string	src of	length
       bytes  is long enough to	be decoded by Tcl_UtfToUniChar/Tcl_UtfNext, or
       0 otherwise.  This function does	not guarantee that the UTF-8 string is
       properly	formed.	 This routine is used by procedures that are operating
       on a byte at a time and need to know if a  full	Tcl_UniChar  has  been
       seen.

       Tcl_NumUtfChars	corresponds  to	 strlen	for UTF-8 strings.  It returns
       the number of Tcl_UniChars that are represented	by  the	 UTF-8	string
       src.   The  length of the source	string is length bytes.	 If the	length
       is negative, all	bytes up to the	first null byte	are used.

       Tcl_UtfFindFirst	corresponds to strchr for UTF-8	strings.  It returns a
       pointer	to the first occurrence	of the Tcl_UniChar ch in the null-ter-
       minated UTF-8 string src.  The null terminator is  considered  part  of
       the UTF-8 string.

       Tcl_UtfFindLast corresponds to strrchr for UTF-8	strings.  It returns a
       pointer to the last occurrence of the Tcl_UniChar ch in the null-termi-
       nated  UTF-8 string src.	 The null terminator is	considered part	of the
       UTF-8 string.

       Given src, a pointer to some location in	a  UTF-8  string,  Tcl_UtfNext
       returns	a  pointer  to	the  next  UTF-8 character in the string.  The
       caller must not ask for the next	character after	the last character  in
       the string if the string	is not terminated by a null character. Tcl_Ut-
       fCharComplete can be used in that case to make sure  enough  bytes  are
       available before	calling	Tcl_UtfNext.

       Tcl_UtfPrev  is	used to	step backward through but not beyond the UTF-8
       string that begins at start.  If	the UTF-8 string is made  up  entirely
       of complete and well-formed characters, and src points to the lead byte
       of one of those characters (or to the location one byte past the	end of
       the string), then repeated calls	of Tcl_UtfPrev will return pointers to
       the lead	bytes of each character	in the	string,	 one  character	 at  a
       time, terminating when it returns start.

       When the	conditions of completeness and well-formedness may not be sat-
       isfied, a more precise description of the function  of  Tcl_UtfPrev  is
       necessary.  It always returns a pointer greater than or equal to	start;
       that is,	always a pointer to a location in the string.  It  always  re-
       turns  a	 pointer  to  a	byte that begins a character when scanning for
       characters beginning from start.	When src is greater than start,	it al-
       ways  returns a pointer less than src and greater than or equal to (src
       - TCL_UTF_MAX).	The character that begins at the returned  pointer  is
       the  first  one that either includes the	byte src[-1], or might include
       it if the right trail bytes are present at src and greater. Tcl_UtfPrev
       never  reads  the  byte	src[0]	nor  the  byte	start[-1] nor the byte
       src[-TCL_UTF_MAX-1].

       Tcl_UniCharAtIndex corresponds to a C string array dereference  or  the
       Pascal  Ord()  function.	 It returns the	Tcl_UniChar represented	at the
       specified character (not	byte) index in	the  UTF-8  string  src.   The
       source  string must contain at least index characters.  Behavior	is un-
       defined if a negative index is given.

       Tcl_UtfAtIndex returns a	pointer	to the specified character (not	 byte)
       index in	the UTF-8 string src.  The source string must contain at least
       index characters.  This is equivalent to	calling	Tcl_UtfToUniChar index
       times.	If a negative index is given, the return pointer points	to the
       first character in the source string.

       Tcl_UtfBackslash	is a utility procedure used by several of the Tcl com-
       mands.	It  parses a backslash sequence	and stores the properly	formed
       UTF-8 character represented by the backslash  sequence  in  the	output
       buffer  dst.   At  most	TCL_UTF_MAX  bytes  are	 stored	in the buffer.
       Tcl_UtfBackslash	modifies *readPtr to contain the number	 of  bytes  in
       the  backslash sequence,	including the backslash	character.  The	return
       value is	the number of bytes stored in the output buffer.

       See the Tcl manual entry	for information	on  the	 valid	backslash  se-
       quences.	  All  of  the sequences described in the Tcl manual entry are
       supported by Tcl_UtfBackslash.

KEYWORDS
       utf, unicode, backslash

Tcl				      8.1				Utf(3)

NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | KEYWORDS

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