tclstringobj.c

linux系统下的音频通信

}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendToObj --
 *
 *	This procedure appends a sequence of bytes to an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The bytes at *bytes are appended to the string representation
 *	of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendToObj(objPtr, bytes, length)
    register Tcl_Obj *objPtr;	/* Points to the object to append to. */
    char *bytes;		/* Points to the bytes to append to the
				 * object. */
    register int length;	/* The number of bytes to append from
				 * "bytes". If < 0, then append all bytes
				 * up to NULL byte. */
{
    int newLength, oldLength;

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_AppendToObj called with shared object");
    }
    if (objPtr->typePtr != &tclStringType) {
	ConvertToStringType(objPtr);
    }
    if (length < 0) {
	length = strlen(bytes);
    }
    if (length == 0) {
	return;
    }
    oldLength = objPtr->length;
    newLength = length + oldLength;
    if ((long)newLength > objPtr->internalRep.longValue) {
	/*
	 * There isn't currently enough space in the string
	 * representation so allocate additional space.  In fact,
	 * overallocate so that there is room for future growth without
	 * having to reallocate again.
	 */

	Tcl_SetObjLength(objPtr, 2*newLength);
    }
    if (length > 0) {
	memcpy((VOID *) (objPtr->bytes + oldLength), (VOID *) bytes,
	       (size_t) length);
	objPtr->length = newLength;
	objPtr->bytes[objPtr->length] = 0;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendStringsToObj --
 *
 *	This procedure appends one or more null-terminated strings
 *	to an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The contents of all the string arguments are appended to the
 *	string representation of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendStringsToObj TCL_VARARGS_DEF(Tcl_Obj *,arg1)
{
    va_list argList;
    register Tcl_Obj *objPtr;
    int newLength, oldLength;
    register char *string, *dst;

    objPtr = (Tcl_Obj *) TCL_VARARGS_START(Tcl_Obj *,arg1,argList);
    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_AppendStringsToObj called with shared object");
    }
    if (objPtr->typePtr != &tclStringType) {
	ConvertToStringType(objPtr);
    }

    /*
     * Figure out how much space is needed for all the strings, and
     * expand the string representation if it isn't big enough. If no
     * bytes would be appended, just return.
     */

    newLength = oldLength = objPtr->length;
    while (1) {
	string = va_arg(argList, char *);
	if (string == NULL) {
	    break;
	}
	newLength += strlen(string);
    }
    if (newLength == oldLength) {
	return;
    }

    if ((long)newLength > objPtr->internalRep.longValue) {
	/*
	 * There isn't currently enough space in the string
	 * representation so allocate additional space.  If the current
	 * string representation isn't empty (i.e. it looks like we're
	 * doing a series of appends) then overallocate the space so
	 * that we won't have to do as much reallocation in the future.
	 */

	Tcl_SetObjLength(objPtr,
		(objPtr->length == 0) ? newLength : 2*newLength);
    }

    /*
     * Make a second pass through the arguments, appending all the
     * strings to the object.
     */

    TCL_VARARGS_START(Tcl_Obj *,arg1,argList);
    dst = objPtr->bytes + oldLength;
    while (1) {
	string = va_arg(argList, char *);
	if (string == NULL) {
	    break;
	}
	while (*string != 0) {
	    *dst = *string;
	    dst++;
	    string++;
	}
    }

    /*
     * Add a null byte to terminate the string.  However, be careful:
     * it's possible that the object is totally empty (if it was empty
     * originally and there was nothing to append).  In this case dst is
     * NULL; just leave everything alone.
     */

    if (dst != NULL) {
	*dst = 0;
    }
    objPtr->length = newLength;
    va_end(argList);
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertToStringType --
 *
 *	This procedure converts the internal representation of an object
 *	to "expandable string" type.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Any old internal reputation for objPtr is freed and the
 *	internal representation is set to that for an expandable string
 *	(the field internalRep.longValue holds 1 less than the allocated
 *	length of objPtr's string representation).
 *
 *----------------------------------------------------------------------
 */

static void
ConvertToStringType(objPtr)
    register Tcl_Obj *objPtr;	/* Pointer to object.  Must have a
				 * typePtr that isn't &tclStringType. */
{
    if (objPtr->typePtr != NULL) {
	if (objPtr->bytes == NULL) {
	    objPtr->typePtr->updateStringProc(objPtr);
	}
	if (objPtr->typePtr->freeIntRepProc != NULL) {
	    objPtr->typePtr->freeIntRepProc(objPtr);
	}
    }
    objPtr->typePtr = &tclStringType;
    if (objPtr->bytes != NULL) {
	objPtr->internalRep.longValue = (long)objPtr->length;
    } else {
	objPtr->internalRep.longValue = 0;
	objPtr->length = 0;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DupStringInternalRep --
 *
 *	Initialize the internal representation of a new Tcl_Obj to a
 *	copy of the internal representation of an existing string object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	copyPtr's internal rep is set to a copy of srcPtr's internal
 *	representation.
 *
 *----------------------------------------------------------------------
 */

static void
DupStringInternalRep(srcPtr, copyPtr)
    register Tcl_Obj *srcPtr;	/* Object with internal rep to copy.  Must
				 * have an internal representation of type
				 * "expandable string". */
    register Tcl_Obj *copyPtr;	/* Object with internal rep to set.  Must
				 * not currently have an internal rep.*/
{
    /*
     * Tricky point: the string value was copied by generic object
     * management code, so it doesn't contain any extra bytes that
     * might exist in the source object.
     */

    copyPtr->internalRep.longValue = (long)copyPtr->length;
    copyPtr->typePtr = &tclStringType;
}

/*
 *----------------------------------------------------------------------
 *
 * SetStringFromAny --
 *
 *	Create an internal representation of type "expandable string"
 *	for an object.
 *
 * Results:
 *	This operation always succeeds and returns TCL_OK.
 *
 * Side effects:
 *	This procedure does nothing; there is no advantage in converting
 *	the internal representation now, so we just defer it.
 *
 *----------------------------------------------------------------------
 */

static int
SetStringFromAny(interp, objPtr)
    Tcl_Interp *interp;		/* Used for error reporting if not NULL. */
    Tcl_Obj *objPtr;		/* The object to convert. */
{
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * UpdateStringOfString --
 *
 *	Update the string representation for an object whose internal
 *	representation is "expandable string".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
UpdateStringOfString(objPtr)
    Tcl_Obj *objPtr;		/* Object with string rep to update. */
{
    /*
     * The string is almost always valid already, in which case there's
     * nothing for us to do. The only case we have to worry about is if
     * the object is totally null. In this case, set the string rep to
     * an empty string.
     */

    if (objPtr->bytes == NULL) {
	objPtr->bytes = tclEmptyStringRep;
	objPtr->length = 0;
    }
    return;
}