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NAME
Tcl_UniChar, Tcl_UniCharToUtf, Tcl_UtfToUniChar,
Tcl_UniCharToUtfDString, Tcl_UtfToUniCharDString,
Tcl_UniCharLen, Tcl_UniCharNcmp, Tcl_UtfCharComplete,
Tcl_NumUtfChars, Tcl_UtfFindFirst, Tcl_UtfFindLast,
Tcl_UtfNext, Tcl_UtfPrev, Tcl_UniCharAtIndex,
Tcl_UtfAtIndex, 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, numChars, dstPtr)
Tcl_UniChar *
Tcl_UtfToUniCharDString(src, len, dstPtr)
int
Tcl_UniCharLen(uniStr)
int
Tcl_UniCharNcmp(uniStr, uniStr, num)
int
Tcl_UtfNcmp(src, src, num)
int
Tcl_UtfNcasecmp(src, src, num)
int
Tcl_UtfCharComplete(src, len)
int
Tcl_NumUtfChars(src, len)
char *
Tcl_UtfFindFirst(src, ch)
char *
Tcl_UtfFindLast(src, ch)
char *
Tcl_UtfNext(src)
char *
Tcl_UtfPrev(src, start)
Tcl_UniChar
Tcl_UniCharAtIndex(src, index)
char *
Tcl_UtfAtIndex(src, index)
int
Tcl_UtfBackslash(src, readPtr, dst)
ARGUMENTS
char *buf (out) Buffer in which the
UTF-8 representa-
tion of the
Tcl_UniChar is
stored. At most
TCL_UTF_MAX bytes
are stored in the
buffer.
int ch (in) The Tcl_UniChar 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 Tcl_UniChar *uniStr (in) A NULL-terminated
Unicode string.
int len (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 numChars (in) The length of the
Unicode string in
characters. Must
be greater than or
equal to 0.
Tcl_DString *dstPtr (in/out) A pointer to a
previously-
initialized
Tcl_DString.
unsigned long num (in) The number of char-
acters 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,
including the
backslash charac-
ter.
char *dst (out) Buffer in which the
bytes represented
by the backslash
sequence are
stored. At most
TCL_UTF_MAX bytes
are stored in the
buffer.
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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 starting 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 *chPtr as a Tcl_UniChar between 0x0000
and 0x00ff 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 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 coverts the given UTF-8 string to
Unicode, storing the result in the previously-initialized
Tcl_Dstring. you may either specify the length of the given
UTF-8 string 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 accepts a NULL-terminated Unicode string and returns the
number of Unicode characters (not bytes) in that string.
Tcl_UniCharNcmp corresponds to strncmp for Unicode charac-
ters. It accepts two NULL-terminated Unicode strings and
the number of characters to compare. (Both strings are
assumed to be at least len characters long.)
Tcl_UniCharNcmp 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_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 len 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 len bytes is long enough to be decoded by
Tcl_UtfToUniChar, 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
len 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 occurance of the
Tcl_UniChar ch in the NULL-terminated 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 occurance of the
Tcl_UniChar ch in the NULL terminated 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.
Given src, a pointer to some location in a UTF-8 string,
Tcl_UtfPrev returns a pointer to the previous UTF-8 charac-
ter in the string. This function will not back up to a
position before start, the start of the UTF-8 string. If
src was already at start, the return value will be start.
Tcl_UniCharAtIndex corresponds to a C string array derefer-
ence 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 undefined 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_UtfNext 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 commands. 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 sequences. All of the sequences described in the
Tcl manual entry are supported by Tcl_UtfBackslash.
KEYWORDS
utf, unicode, backslash
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