Tcl Source Code

	    q += qInc;
	    bytesLeft -= qInc;
	} while (bytesLeft);

	if (bytesLeft == 0) {
	    /* No match; trim task done; *p is last non-trimmed char */
	    p += pInc;
	    break;
	}

    } while (p > bytes);

    return numBytes - (p - bytes);
}

/*
 *----------------------------------------------------------------------
 *
 * TclTrimLeft --
 *	Takes two counted strings in the Tcl encoding which must both be
 *	null terminated.  Conceptually trims from the left side of the
 *	first string all characters found in the second string.
 *
 * Results:
 *	The number of bytes to be removed from the start of the string.

 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

 * Side effects:
 *	Memory is allocated for the result; the caller is responsible for
 *	freeing the memory.
 *
 *----------------------------------------------------------------------
 */

/* The whitespace characters trimmed during [concat] operations */
#define CONCAT_WS " \f\v\r\t\n"
#define CONCAT_WS_SIZE (int) (sizeof(CONCAT_WS "") - 1)

char *
Tcl_Concat(
    int argc,			/* Number of strings to concatenate. */
    const char *const *argv)	/* Array of strings to concatenate. */
{
    int i, needSpace = 0, bytesNeeded = 0;
    char *result, *p;

    /* Dispose of the empty result corner case first to simplify later code */
    if (argc == 0) {
	result = (char *) ckalloc(1);
	result[0] = '\0';
	return result;
    }

    /* First allocate the result buffer at the size required */
    for (i = 0;  i < argc;  i++) {
	bytesNeeded += strlen(argv[i]);
	if (bytesNeeded < 0) {
	    Tcl_Panic("Tcl_Concat: max size of Tcl value exceeded");
	}
    }

    if (bytesNeeded + argc - 1 < 0) {
	/*
	 * Panic test could be tighter, but not going to bother for 
	 * this legacy routine.
	 */
	Tcl_Panic("Tcl_Concat: max size of Tcl value exceeded");
    }
    /* All element bytes + (argc - 1) spaces + 1 terminating NULL */
    result = (char *) ckalloc((unsigned) (bytesNeeded + argc));

    for (p = result, i = 0;  i < argc;  i++) {
	int trim, elemLength;
	const char *element;

	





	element = argv[i];
	elemLength = strlen(argv[i]);

	/* Trim away the leading whitespace */
	trim = TclTrimLeft(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
	element += trim;
	elemLength -= trim;

	/*
	 * Trim away the trailing whitespace.  Do not permit trimming
	 * to expose a final backslash character.
	 */


	trim = TclTrimRight(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
	trim -= trim && (element[elemLength - trim - 1] == '\\');
	elemLength -= trim;


	/* If we're left with empty element after trimming, do nothing */
	if (elemLength == 0) {
	    continue;
	}


	/* Append to the result with space if needed */
	if (needSpace) {
	    *p++ = ' ';

	}


	memcpy(p, element, (size_t) elemLength);
	p += elemLength;
	needSpace = 1;
    }
    *p = '\0';
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConcatObj --

 */

Tcl_Obj *
Tcl_ConcatObj(
    int objc,			/* Number of objects to concatenate. */
    Tcl_Obj *const objv[])	/* Array of objects to concatenate. */
{
    int i, elemLength, needSpace = 0, bytesNeeded = 0;
    const char *element;
    Tcl_Obj *objPtr, *resPtr;

    /*
     * Check first to see if all the items are of list type or empty. If so,
     * we will concat them together as lists, and return a list object. This
     * is only valid when the lists are in canonical form.
     */

    }

    /*
     * Something cannot be determined to be safe, so build the concatenation
     * the slow way, using the string representations.
     */

    /* First try to pre-allocate the size required */
    for (i = 0;  i < objc;  i++) {
	element = TclGetStringFromObj(objv[i], &elemLength);
	bytesNeeded += elemLength;
	if (bytesNeeded < 0) {
	    break;
	}
    }
    /*
     * Does not matter if this fails, will simply try later to build up
     * the string with each Append reallocating as needed with the usual
     * string append algorithm.  When that fails it will report the error.
     */
    TclNewObj(resPtr);
    Tcl_AttemptSetObjLength(resPtr, bytesNeeded + objc - 1);
    Tcl_SetObjLength(resPtr, 0);

    for (i = 0;  i < objc;  i++) {
	int trim;

	

	element = TclGetStringFromObj(objv[i], &elemLength);

	/* Trim away the leading whitespace */
	trim = TclTrimLeft(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
	element += trim;
	elemLength -= trim;

	/*
	 * Trim away the trailing whitespace.  Do not permit trimming
	 * to expose a final backslash character.
	 */

	trim = TclTrimRight(element, elemLength, CONCAT_WS, CONCAT_WS_SIZE);
	trim -= trim && (element[elemLength - trim - 1] == '\\');
	elemLength -= trim;

	/* If we're left with empty element after trimming, do nothing */
	if (elemLength == 0) {
	    continue;
	}