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Хостинг:
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NAME
Tcl_NewStringObj, Tcl_NewUnicodeObj, Tcl_SetStringObj,
Tcl_SetUnicodeObj, Tcl_GetStringFromObj, Tcl_GetString,
Tcl_GetUnicode, Tcl_GetUniChar, Tcl_GetCharLength,
Tcl_GetRange, Tcl_AppendToObj, Tcl_AppendUnicodeToObj,
Tcl_AppendStringsToObj, Tcl_AppendStringsToObjVA,
Tcl_AppendObjToObj, Tcl_SetObjLength, Tcl_ConcatObj - mani-
pulate Tcl objects as strings
SYNOPSIS
#include <tcl.h>
Tcl_Obj *
Tcl_NewStringObj(bytes, length)
Tcl_Obj * |
Tcl_NewUnicodeObj(unicode, numChars) |
void
Tcl_SetStringObj(objPtr, bytes, length)
void |
Tcl_SetUnicodeObj(objPtr, unicode, numChars) |
char *
Tcl_GetStringFromObj(objPtr, lengthPtr)
char *
Tcl_GetString(objPtr)
Tcl_UniChar * |
Tcl_GetUnicode(objPtr) |
Tcl_UniChar |
Tcl_GetUniChar(objPtr, index) |
int |
Tcl_GetCharLength(objPtr) |
Tcl_Obj * |
Tcl_GetRange(objPtr, first, last) |
void
Tcl_AppendToObj(objPtr, bytes, length)
void |
Tcl_AppendUnicodeToObj(objPtr, unicode, numChars) |
void
Tcl_AppendObjToObj(objPtr, appendObjPtr)
void
Tcl_AppendStringsToObj(objPtr, string, string, ... (char *) NULL)
void
Tcl_AppendStringsToObjVA(objPtr, argList)
void
Tcl_SetObjLength(objPtr, newLength)
Tcl_Obj *
Tcl_ConcatObj(objc, objv)
ARGUMENTS
char *bytes (in) Points to the first
byte of an array of
bytes used to set or
append to a string
object. This byte
array may contain
embedded null bytes
unless length is
negative.
int length (in) The number of bytes
to copy from bytes
when initializing,
setting, or appending
to a string object.
If negative, all
bytes up to the first
null are used.
Tcl_UniChar *unicode (in) Points to the first
byte of an array of
Unicode characters
used to set or append
to a string object.
This byte array may
contain embedded null
characters unless
numChars is negative. |
int numChars (in) ||
The number of Unicode |
characters to copy |
from unicode when |
initializing, set- |
ting, or appending to |
a string object. If |
negative, all charac- |
ters up to the first |
null character are |
used. |
int index (in) ||
The index of the |
Unicode character to |
return. |
int first (in) ||
The index of the |
first Unicode charac- |
ter in the Unicode |
range to be returned |
as a new object. |
int last (in) ||
The index of the last |
Unicode character in |
the Unicode range to |
be returned as a new |
object.
Tcl_Obj *objPtr (in/out) Points to an object
to manipulate.
Tcl_Obj *appendObjPtr (in) The object to append
to objPtr in
Tcl_AppendObjToObj.
int *lengthPtr (out) If non-NULL, the
location where
Tcl_GetStringFromObj
will store the the
length of an object's
string representa-
tion.
char *string (in) Null-terminated
string value to
append to objPtr.
va_list argList (in) An argument list
which must have been
initialised using
TCL_VARARGS_START,
and cleared using
va_end.
int newLength (in) New length for the
string value of
objPtr, not including
the final NULL char-
acter.
int objc (in) The number of ele-
ments to concatenate.
Tcl_Obj *objv[] (in) The array of objects
to concatenate.
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DESCRIPTION
The procedures described in this manual entry allow Tcl
objects to be manipulated as string values. They use the
internal representation of the object to store additional
information to make the string manipulations more efficient.
In particular, they make a series of append operations effi-
cient by allocating extra storage space for the string so
that it doesn't have to be copied for each append. Also, |
indexing and length computations are optimized because the |
Unicode string representation is calculated and cached as |
needed.
Tcl_NewStringObj and Tcl_SetStringObj create a new object or |
modify an existing object to hold a copy of the string given |
by bytes and length. Tcl_NewUnicodeObj and |
Tcl_SetUnicodeObj create a new object or modify an existing |
object to hold a copy of the Unicode string given by unicode |
and numChars. Tcl_NewStringObj and Tcl_NewUnicodeObj return |
a pointer to a newly created object with reference count |
zero. All four procedures set the object to hold a copy of |
the specified string. Tcl_SetStringObj and |
Tcl_SetUnicodeObj free any old string representation as well |
as any old internal representation of the object.
Tcl_GetStringFromObj and Tcl_GetString return an object's
string representation. This is given by the returned byte
pointer and (for Tcl_GetStringFromObj) length, which is
stored in lengthPtr if it is non-NULL. If the object's UTF
string representation is invalid (its byte pointer is NULL),
the string representation is regenerated from the object's
internal representation. The storage referenced by the
returned byte pointer is owned by the object manager and
should not be modified by the caller. The procedure
Tcl_GetString is used in the common case where the caller
does not need the length of the string representation.
Tcl_GetUnicode returns an object's value as a Unicode |
string. Tcl_GetUniChar returns the index'th character in |
the object's Unicode representation. |
Tcl_GetRange returns a newly created object comprised of the |
characters between first and last (inclusive) in the |
object's Unicode representation. If the object's Unicode |
representation is invalid, the Unicode representation is |
regenerated from the object's string representation. |
Tcl_GetCharLength returns the number of characters (as |
opposed to bytes) in the string object. |
Tcl_AppendToObj appends the data given by bytes and length |
to the string representation of the object specified by |
objPtr. If the object has an invalid string representation, |
then an attempt is made to convert bytes is to the Unicode |
format. If the conversion is successful, then the converted |
form of bytes is appended to the object's Unicode represen- |
tation. Otherwise, the object's Unicode representation is |
invalidated and converted to the UTF format, and bytes is |
appended to the object's new string representation. |
Tcl_AppendUnicodeToObj appends the Unicode string given by |
unicode and numChars to the object specified by objPtr. If |
the object has an invalid Unicode representation, then |
unicode is converted to the UTF format and appended to the |
object's string representation. Appends are optimized to |
handle repeated appends relatively efficiently (it overallo- |
cates the string or Unicode space to avoid repeated reallo- |
cations and copies of object's string value). |
Tcl_AppendObjToObj is similar to Tcl_AppendToObj, but it |
appends the string or Unicode value (whichever exists and is |
best suited to be appended to objPtr) of appendObjPtr to |
objPtr.
Tcl_AppendStringsToObj is similar to Tcl_AppendToObj except
that it can be passed more than one value to append and each
value must be a null-terminated string (i.e. none of the
values may contain internal null characters). Any number of
string arguments may be provided, but the last argument must
be a NULL pointer to indicate the end of the list.
Tcl_AppendStringsToObjVA is the same as
Tcl_AppendStringsToObj except that instead of taking a vari-
able number of arguments it takes an argument list.
The Tcl_SetObjLength procedure changes the length of the
string value of its objPtr argument. If the newLength argu-
ment is greater than the space allocated for the object's
string, then the string space is reallocated and the old
value is copied to the new space; the bytes between the old
length of the string and the new length may have arbitrary
values. If the newLength argument is less than the current
length of the object's string, with objPtr->length is
reduced without reallocating the string space; the original
allocated size for the string is recorded in the object, so
that the string length can be enlarged in a subsequent call
to Tcl_SetObjLength without reallocating storage. In all
cases Tcl_SetObjLength leaves a null character at objPtr-
>bytes[newLength].
The Tcl_ConcatObj function returns a new string object whose
value is the space-separated concatenation of the string
representations of all of the objects in the objv array.
Tcl_ConcatObj eliminates leading and trailing white space as
it copies the string representations of the objv array to
the result. If an element of the objv array consists of
nothing but white space, then that object is ignored
entirely. This white-space removal was added to make the
output of the concat command cleaner-looking. Tcl_ConcatObj
returns a pointer to a newly-created object whose ref count
is zero.
SEE ALSO
Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount
KEYWORDS
append, internal representation, object, object type, string
object, string type, string representation, concat, con-
catenate, unicode
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