Utf(3) Tcl Library Procedures Utf(3)
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NAME
Tcl_UniChar, Tcl_UniCharCaseMatch, Tcl_UniCharNcasecmp, 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_UniCharNcasecmp(uniStr, uniStr, num) |
int |
Tcl_UniCharCaseMatch(uniStr, uniPattern, nocase) |
int
Tcl_UtfNcmp(src, src, num)
int
Tcl_UtfNcasecmp(src, src, num)
int
Tcl_UtfCharComplete(src, len)
int
Tcl_NumUtfChars(src, len)
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 Tcl_UniChar to be converted or exam-
ined.
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.
CONST Tcl_UniChar *uniPattern(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 char-
acters. 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 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, including
the backslash character.
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. |
int nocase (in) ||
Specifies whether the match should be done |
case-sensitive (0) or case-insensitive |
(1).
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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 charac-
ter 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 converts 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 and Tcl_UniCharNcasecmp correspond to strncmp and strncasecmp,
respectively, for Unicode characters. They 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_UniCharNcasecmp is the Uni-
code 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-termi-
nated 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 occurrence 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 occurrence 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 if the string is not termi-
nated by a null character.
Given src, a pointer to some location in a UTF-8 string (or to a null byte immedi-
ately following such a string), Tcl_UtfPrev returns a pointer to the closest pre-
ceding byte that starts a UTF-8 character. 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 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 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 repre-
sented 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
Tcl 8.1 Utf(3)
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