Tcl Source Code

 * MODULE_SCOPE void	TclGrowTokenArray(Tcl_Token *tokenPtr, int used,
 *				int available, int append,
 *				Tcl_Token *staticPtr);
 * MODULE_SCOPE void	TclGrowParseTokenArray(Tcl_Parse *parsePtr,
 *				int append);
 *----------------------------------------------------------------
 */

/* General tuning for minimum growth in Tcl growth algorithms */
#ifndef TCL_MIN_GROWTH
#  ifdef TCL_GROWTH_MIN_ALLOC
     /* Support for any legacy tuners */
#    define TCL_MIN_GROWTH TCL_GROWTH_MIN_ALLOC
#  else
#    define TCL_MIN_GROWTH 1024
#  endif
#endif

/* Token growth tuning, default to the general value. */
#ifndef TCL_MIN_TOKEN_GROWTH
#define TCL_MIN_TOKEN_GROWTH TCL_MIN_GROWTH/sizeof(Tcl_Token)
#endif

#define TCL_MAX_TOKENS (int)(UINT_MAX / sizeof(Tcl_Token))
#define TclGrowTokenArray(tokenPtr, used, available, append, staticPtr)	\
    do {								\
	int needed = (used) + (append);					\
	if (needed > TCL_MAX_TOKENS) {					\
	    Tcl_Panic("max # of tokens for a Tcl parse (%d) exceeded",	\
		    TCL_MAX_TOKENS);					\
	}								\

 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tclInt.h"





/*
 * Prototypes for functions defined later in this file:
 */

static List *		AttemptNewList(Tcl_Interp *interp, int objc,
			    Tcl_Obj *const objv[]);
static List *		NewListIntRep(int objc, Tcl_Obj *const objv[], int p);

const Tcl_ObjType tclListType = {
    "list",			/* name */
    FreeListInternalRep,	/* freeIntRepProc */
    DupListInternalRep,		/* dupIntRepProc */
    UpdateStringOfList,		/* updateStringProc */
    SetListFromAny		/* setFromAnyProc */
};

#ifndef TCL_MIN_ELEMENT_GROWTH
#define TCL_MIN_ELEMENT_GROWTH TCL_MIN_GROWTH/sizeof(Tcl_Obj *)
#endif


/*
 *----------------------------------------------------------------------
 *
 * NewListIntRep --
 *
 *	Creates a list internal rep with space for objc elements.  objc

	    newMax = listRepPtr->maxElemCount;
	}

	listRepPtr = AttemptNewList(NULL, newMax, NULL);
	if (listRepPtr == NULL) {
	    unsigned int limit = LIST_MAX - numRequired;
	    unsigned int extra = numRequired - numElems
		    + TCL_MIN_ELEMENT_GROWTH;
	    int growth = (int) ((extra > limit) ? limit : extra);

	    listRepPtr = AttemptNewList(NULL, numRequired + growth, NULL);
	    if (listRepPtr == NULL) {
		listRepPtr = AttemptNewList(interp, numRequired, NULL);
		if (listRepPtr == NULL) {
		    return TCL_ERROR;

 * TCL STRING GROWTH ALGORITHM
 *
 * When growing strings (during an append, for example), the following growth
 * algorithm is used:
 *
 *   Attempt to allocate 2 * (originalLength + appendLength)
 *   On failure:
 *	attempt to allocate originalLength + 2*appendLength + TCL_MIN_GROWTH

 *
 * This algorithm allows very good performance, as it rapidly increases the
 * memory allocated for a given string, which minimizes the number of
 * reallocations that must be performed. However, using only the doubling
 * algorithm can lead to a significant waste of memory. In particular, it may
 * fail even when there is sufficient memory available to complete the append
 * request (but there is not 2*totalLength memory available). So when the
 * doubling fails (because there is not enough memory available), the
 * algorithm requests a smaller amount of memory, which is still enough to
 * cover the request, but which hopefully will be less than the total
 * available memory.
 *
 * The addition of TCL_MIN_GROWTH allows for efficient handling of very
 * small appends. Without this extra slush factor, a sequence of several small
 * appends would cause several memory allocations. As long as
 * TCL_MIN_GROWTH is a reasonable size, we can avoid that behavior.
 *
 * The growth algorithm can be tuned by adjusting the following parameters:
 *
 * TCL_MIN_GROWTH		Additional space, in bytes, to allocate when
 *				the double allocation has failed. Default is
 *				1024 (1 kilobyte).  See tclInt.h.
 */

#ifndef TCL_MIN_UNICHAR_GROWTH
#define TCL_MIN_UNICHAR_GROWTH	TCL_MIN_GROWTH/sizeof(Tcl_UniChar)
#endif

static void
GrowStringBuffer(
    Tcl_Obj *objPtr,
    int needed,
    int flag)

	if (ptr == NULL) {
	    /*
	     * Take care computing the amount of modest growth to avoid
	     * overflow into invalid argument values for attempt.
	     */

	    unsigned int limit = INT_MAX - needed;
	    unsigned int extra = needed - objPtr->length + TCL_MIN_GROWTH;
	    int growth = (int) ((extra > limit) ? limit : extra);

	    attempt = needed + growth;
	    ptr = attemptckrealloc(objPtr->bytes, attempt + 1);
	}
    }
    if (ptr == NULL) {

	    /*
	     * Take care computing the amount of modest growth to avoid
	     * overflow into invalid argument values for attempt.
	     */

	    unsigned int limit = STRING_MAXCHARS - needed;
	    unsigned int extra = needed - stringPtr->numChars
		    + TCL_MIN_UNICHAR_GROWTH;
	    int growth = (int) ((extra > limit) ? limit : extra);

	    attempt = needed + growth;
	    ptr = stringAttemptRealloc(stringPtr, attempt);
	}
    }
    if (ptr == NULL) {