tclutil.c

tcl是工具命令语言

    if (length < 0) {
	length = strlen(string);
    }
    newSize = length + dsPtr->length;

    /*
     * Allocate a larger buffer for the string if the current one isn't
     * large enough. Allocate extra space in the new buffer so that there
     * will be room to grow before we have to allocate again.
     */

    if (newSize >= dsPtr->spaceAvl) {
	dsPtr->spaceAvl = newSize * 2;
	if (dsPtr->string == dsPtr->staticSpace) {
	    char *newString;

	    newString = (char *) ckalloc((unsigned) dsPtr->spaceAvl);
	    memcpy((VOID *) newString, (VOID *) dsPtr->string,
		    (size_t) dsPtr->length);
	    dsPtr->string = newString;
	} else {
	    dsPtr->string = (char *) ckrealloc((VOID *) dsPtr->string,
		    (size_t) dsPtr->spaceAvl);
	}
    }

    /*
     * Copy the new string into the buffer at the end of the old
     * one.
     */

    for (dst = dsPtr->string + dsPtr->length, end = string+length;
	    string < end; string++, dst++) {
	*dst = *string;
    }
    *dst = '\0';
    dsPtr->length += length;
    return dsPtr->string;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringAppendElement --
 *
 *	Append a list element to the current value of a dynamic string.
 *
 * Results:
 *	The return value is a pointer to the dynamic string's new value.
 *
 * Side effects:
 *	String is reformatted as a list element and added to the current
 *	value of the string.  Memory gets reallocated if needed to
 *	accomodate the string's new size.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_DStringAppendElement(dsPtr, string)
    Tcl_DString *dsPtr;		/* Structure describing dynamic string. */
    CONST char *string;		/* String to append.  Must be
				 * null-terminated. */
{
    int newSize, flags, strSize;
    char *dst;

    strSize = ((string == NULL) ? 0 : strlen(string));
    newSize = Tcl_ScanCountedElement(string, strSize, &flags)
	+ dsPtr->length + 1;

    /*
     * Allocate a larger buffer for the string if the current one isn't
     * large enough.  Allocate extra space in the new buffer so that there
     * will be room to grow before we have to allocate again.
     * SPECIAL NOTE: must use memcpy, not strcpy, to copy the string
     * to a larger buffer, since there may be embedded NULLs in the
     * string in some cases.
     */

    if (newSize >= dsPtr->spaceAvl) {
	dsPtr->spaceAvl = newSize * 2;
	if (dsPtr->string == dsPtr->staticSpace) {
	    char *newString;

	    newString = (char *) ckalloc((unsigned) dsPtr->spaceAvl);
	    memcpy((VOID *) newString, (VOID *) dsPtr->string,
		    (size_t) dsPtr->length);
	    dsPtr->string = newString;
	} else {
	    dsPtr->string = (char *) ckrealloc((VOID *) dsPtr->string,
		    (size_t) dsPtr->spaceAvl);
	}
    }

    /*
     * Convert the new string to a list element and copy it into the
     * buffer at the end, with a space, if needed.
     */

    dst = dsPtr->string + dsPtr->length;
    if (TclNeedSpace(dsPtr->string, dst)) {
	*dst = ' ';
	dst++;
	dsPtr->length++;
    }
    dsPtr->length += Tcl_ConvertCountedElement(string, strSize, dst, flags);
    return dsPtr->string;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringSetLength --
 *
 *	Change the length of a dynamic string.  This can cause the
 *	string to either grow or shrink, depending on the value of
 *	length.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The length of dsPtr is changed to length and a null byte is
 *	stored at that position in the string.  If length is larger
 *	than the space allocated for dsPtr, then a panic occurs.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DStringSetLength(dsPtr, length)
    Tcl_DString *dsPtr;		/* Structure describing dynamic string. */
    int length;			/* New length for dynamic string. */
{
    int newsize;

    if (length < 0) {
	length = 0;
    }
    if (length >= dsPtr->spaceAvl) {
	/*
	 * There are two interesting cases here.  In the first case, the user
	 * may be trying to allocate a large buffer of a specific size.  It
	 * would be wasteful to overallocate that buffer, so we just allocate
	 * enough for the requested size plus the trailing null byte.  In the
	 * second case, we are growing the buffer incrementally, so we need
	 * behavior similar to Tcl_DStringAppend.  The requested length will
	 * usually be a small delta above the current spaceAvl, so we'll end up
	 * doubling the old size.  This won't grow the buffer quite as quickly,
	 * but it should be close enough.
	 */

	newsize = dsPtr->spaceAvl * 2;
	if (length < newsize) {
	    dsPtr->spaceAvl = newsize;
	} else {
	    dsPtr->spaceAvl = length + 1;
	}
	if (dsPtr->string == dsPtr->staticSpace) {
	    char *newString;

	    newString = (char *) ckalloc((unsigned) dsPtr->spaceAvl);
	    memcpy((VOID *) newString, (VOID *) dsPtr->string,
		    (size_t) dsPtr->length);
	    dsPtr->string = newString;
	} else {
	    dsPtr->string = (char *) ckrealloc((VOID *) dsPtr->string,
		    (size_t) dsPtr->spaceAvl);
	}
    }
    dsPtr->length = length;
    dsPtr->string[length] = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringFree --
 *
 *	Frees up any memory allocated for the dynamic string and
 *	reinitializes the string to an empty state.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The previous contents of the dynamic string are lost, and
 *	the new value is an empty string.
 *
 *---------------------------------------------------------------------- */

void
Tcl_DStringFree(dsPtr)
    Tcl_DString *dsPtr;		/* Structure describing dynamic string. */
{
    if (dsPtr->string != dsPtr->staticSpace) {
	ckfree(dsPtr->string);
    }
    dsPtr->string = dsPtr->staticSpace;
    dsPtr->length = 0;
    dsPtr->spaceAvl = TCL_DSTRING_STATIC_SIZE;
    dsPtr->staticSpace[0] = '\0';
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringResult --
 *
 *	This procedure moves the value of a dynamic string into an
 *	interpreter as its string result. Afterwards, the dynamic string
 *	is reset to an empty string.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The string is "moved" to interp's result, and any existing
 *	string result for interp is freed. dsPtr is reinitialized to
 *	an empty string.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DStringResult(interp, dsPtr)
    Tcl_Interp *interp;		/* Interpreter whose result is to be reset. */
    Tcl_DString *dsPtr;		/* Dynamic string that is to become the
				 * result of interp. */
{
    Tcl_ResetResult(interp);
    
    if (dsPtr->string != dsPtr->staticSpace) {
	interp->result = dsPtr->string;
	interp->freeProc = TCL_DYNAMIC;
    } else if (dsPtr->length < TCL_RESULT_SIZE) {
	interp->result = ((Interp *) interp)->resultSpace;
	strcpy(interp->result, dsPtr->string);
    } else {
	Tcl_SetResult(interp, dsPtr->string, TCL_VOLATILE);
    }
    
    dsPtr->string = dsPtr->staticSpace;
    dsPtr->length = 0;
    dsPtr->spaceAvl = TCL_DSTRING_STATIC_SIZE;
    dsPtr->staticSpace[0] = '\0';
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringGetResult --
 *
 *	This procedure moves an interpreter's result into a dynamic string.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The interpreter's string result is cleared, and the previous
 *	contents of dsPtr are freed.
 *
 *	If the string result is empty, the object result is moved to the
 *	string result, then the object result is reset.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DStringGetResult(interp, dsPtr)
    Tcl_Interp *interp;		/* Interpreter whose result is to be reset. */
    Tcl_DString *dsPtr;		/* Dynamic string that is to become the
				 * result of interp. */
{
    Interp *iPtr = (Interp *) interp;
    
    if (dsPtr->string != dsPtr->staticSpace) {
	ckfree(dsPtr->string);
    }

    /*
     * If the string result is empty, move the object result to the
     * string result, then reset the object result.
     */

    if (*(iPtr->result) == 0) {
	Tcl_SetResult(interp, TclGetString(Tcl_GetObjResult(interp)),
	        TCL_VOLATILE);
    }

    dsPtr->length = strlen(iPtr->result);
    if (iPtr->freeProc != NULL) {
	if ((iPtr->freeProc == TCL_DYNAMIC)
		|| (iPtr->freeProc == (Tcl_FreeProc *) free)) {
	    dsPtr->string = iPtr->result;
	    dsPtr->spaceAvl = dsPtr->length+1;
	} else {
	    dsPtr->string = (char *) ckalloc((unsigned) (dsPtr->length+1));
	    strcpy(dsPtr->string, iPtr->result);
	    (*iPtr->freeProc)(iPtr->result);
	}
	dsPtr->spaceAvl = dsPtr->length+1;
	iPtr->freeProc = NULL;
    } else {
	if (dsPtr->length < TCL_DSTRING_STATIC_SIZE) {
	    dsPtr->string = dsPtr->staticSpace;
	    dsPtr->spaceAvl = TCL_DSTRING_STATIC_SIZE;
	} else {
	    dsPtr->string = (char *) ckalloc((unsigned) (dsPtr->length + 1));
	    dsPtr->spaceAvl = dsPtr->length + 1;
	}
	strcpy(dsPtr->string, iPtr->result);
    }
    
    iPtr->result = iPtr->resultSpace;
    iPtr->resultSpace[0] = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringStartSublist --
 *
 *	This procedure adds the necessary information to a dynamic
 *	string (e.g. " {" to start a sublist.  Future element
 *	appends will be in the sublist rather than the main list.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Characters get added to the dynamic string.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DStringStartSublist(dsPtr)
    Tcl_DString *dsPtr;			/* Dynamic string. */
{
    if (TclNeedSpace(dsPtr->string, dsPtr->string + dsPtr->length)) {
	Tcl_DStringAppend(dsPtr, " {", -1);
    } else {
	Tcl_DStringAppend(dsPtr, "{", -1);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DStringEndSublist --
 *
 *	This procedure adds the necessary characters to a dynamic
 *	string to end a sublist (e.g. "}").  Future element appends
 *	will be in the enclosing (sub)list rather than the current
 *	sublist.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DStringEndSublist(dsPtr)
    Tcl_DString *dsPtr;			/* Dynamic string. */
{
    Tcl_DStringAppend(dsPtr, "}", -1);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_PrintDouble --
 *
 *	Given a floating-point value, this procedure converts it to
 *	an ASCII string using.
 *
 * Results:
 *	The ASCII equivalent of "value" is written at "dst".  It is
 *	written using the current precision, and it is guaranteed to
 *	contain a decimal point or exponent, so that it looks like
 *	a floating-point value and not an integer.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_PrintDouble(interp, value, dst)
    Tcl_Interp *interp;			/* Interpreter whose tcl_precision
					 * variable used to be used to control
					 * printing.  It's ignored now. */
    double value;			/* Value to print as string. */
    char *dst;				/* Where to store converted value;
					 * must have at least TCL_DOUBLE_SPACE
					 * characters. */
{
    char *p, c;
    Tcl_UniChar ch;

    Tcl_MutexLock(&precisionMutex);
    sprintf(dst, precisionFormat, value);
    Tcl_MutexUnlock(&precisionMutex);

    /*
     * If the ASCII result looks like an integer, add ".0" so that it
     * doesn't look like an integer anymore.  This prevents floating-point
     * values from being converted to integers unintentionally.
     * Check for ASCII specifically to speed up the function.
     */

    for (p = dst; *p != 0; ) {
	if (UCHAR(*p) < 0x80) {
	    c = *p++;
	} else {
	    p += Tcl_UtfToUniChar(p, &ch);
	    c = UCHAR(ch);
	}
	if ((c == '.') || isalpha(UCHAR(c))) {	/* INTL: ISO only. */
	    return;
	}
    }
    p[0] = '.';
    p[1] = '0';
    p[2] = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * TclPrecTraceProc --
 *
 *	This procedure is invoked whenever the variable "tcl_precision"
 *	is written.
 *
 * Results:
 *	Returns NULL if all went well, or an error message if the
 *	new value for the variable doesn't make sense.
 *
 * Side effects:
 *	If the new value doesn't make sense then this procedure
 *	undoes the effect of the variable modification.  Otherwise
 *	it modifies the format string that's used by Tcl_PrintDouble.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
char *
TclPrecTraceProc(clientData, interp, name1, name2, flags)
    ClientData clientData;	/* Not used. */
    Tcl_Interp *interp;		/* Interpreter containing variable. */
    CONST char *name1;		/* Name of variable. */
    CONST char *name2;		/* Second part of variable name. */
    int flags;			/* Information about what happened. */
{
    CONST char *value;
    char *end;
    int prec;

    /*
     * If the variable is unset, then recreate the trace.
     */

    if (flags & TCL_TRACE_UNSETS) {
	if ((flags & TCL_TRACE_DESTROYED) && !(flags & TCL_INTERP_DESTROYED)) {
	    Tcl_TraceVar2(interp, name1, name2,
		    TCL_GLOBAL_ONLY|TCL_TRACE_READS|TCL_TRACE_WRITES
		    |TCL_TRACE_UNSETS, TclPrecTraceProc, clientData);
	}
	return (char *) NULL;
    }

    /*
     * When the variable is read, reset its value from our shared
     * value.  This is needed in case the variable was modified in