* doc/Alloc.3: Added entries for Tcl_AttemptAlloc, Tcl_AttempRealloc.

* doc/StringObj.3: Added entry for Tcl_AttemptSetObjLength.

* generic/tclDecls.h:
* generic/tclStubInit.c: Regen'ed stubs files from new tcl.decls.

* generic/tcl.decls: Added stubs for the Tcl_Attempt* memory
allocators and for Tcl_AttemptSetObjLength.

* generic/tcl.h: Added #define's for attemptckalloc,
attemptckrealloc, which map to the Tcl_Attempt* memory allocators.

* generic/tclCkalloc.c: Added non-panic'ing versions of Tcl_Alloc,
Tcl_Realloc, etc.; these are called Tcl_AttemptAlloc,
Tcl_AttemptRealloc, etc.  These are used by
Tcl_AttemptSetObjLength and the string obj append functions.

* generic/tclStringObj.c: Modified string growth algorithm to use
doubling algorithm as long as possible, and only fall back when
that fails.  Added Tcl_AttemptSetObjLength, and modified
AppendUnicodeToUnicodeRep, AppendUtfToUtfRep, and
Tcl_AppendStringsToObjVA to support this.

9 files changed, 341 insertions, 61 deletions

diff --git a/ChangeLog b/ChangeLog
index a19e4e4..922faa1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,29 @@
+2000-09-14  Eric Melski  <ericm@ajubasolutions.com>
+
+	* doc/Alloc.3: Added entries for Tcl_AttemptAlloc, Tcl_AttempRealloc.
+
+	* doc/StringObj.3: Added entry for Tcl_AttemptSetObjLength.
+	
+	* generic/tclDecls.h:
+	* generic/tclStubInit.c: Regen'ed stubs files from new tcl.decls.
+
+	* generic/tcl.decls: Added stubs for the Tcl_Attempt* memory
+	allocators and for Tcl_AttemptSetObjLength.
+
+	* generic/tcl.h: Added #define's for attemptckalloc,
+	attemptckrealloc, which map to the Tcl_Attempt* memory allocators.
+
+	* generic/tclCkalloc.c: Added non-panic'ing versions of Tcl_Alloc,
+	Tcl_Realloc, etc.; these are called Tcl_AttemptAlloc,
+	Tcl_AttemptRealloc, etc.  These are used by
+	Tcl_AttemptSetObjLength and the string obj append functions.
+
+	* generic/tclStringObj.c: Modified string growth algorithm to use
+	doubling algorithm as long as possible, and only fall back when
+	that fails.  Added Tcl_AttemptSetObjLength, and modified
+	AppendUnicodeToUnicodeRep, AppendUtfToUtfRep, and
+	Tcl_AppendStringsToObjVA to support this.
+
 2000-09-07  David Gravereaux <davygrvy@ajubasolutions.com>
 
 	* win/.cvsignore: changed the glob patterns a bit to exclude VC++
diff --git a/doc/Alloc.3 b/doc/Alloc.3
index 405d7fa..c7396a0 100644
--- a/doc/Alloc.3
+++ b/doc/Alloc.3
@@ -4,7 +4,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: Alloc.3,v 1.2 1998/09/14 18:39:45 stanton Exp $
+'\" RCS: @(#) $Id: Alloc.3,v 1.3 2000/09/14 18:42:28 ericm Exp $
 '\" 
 .so man.macros
 .TH Tcl_Alloc 3 7.5 Tcl "Tcl Library Procedures"
@@ -22,6 +22,12 @@ char *
 .sp
 char *
 \fBTcl_Realloc\fR(\fIptr, size\fR)
+.sp
+int
+\fBTcl_AttemptAlloc\fR(\fIsize\fR)
+.sp
+int
+\fBTcl_AttemptRealloc\fR(\fIptr, size\fR)
 .SH ARGUMENTS
 .AS char *size
 .AP int size in
@@ -48,5 +54,11 @@ further allocation.
 \fIptr\fR to \fIsize\fR bytes and returns a pointer to the new block.
 The contents will be unchanged up to the lesser of the new and old
 sizes.  The returned location may be different from \fIptr\fR.
+.PP
+\fBTcl_AttemptAlloc\fR and \fBTcl_AttemptRealloc\fR are identical in
+function to \fBTcl_Alloc\fR and \fBTcl_Realloc\fR, except that
+\fBTcl_AttemptAlloc\fR and \fBTcl_AttemptRealloc\fR will not cause the Tcl
+interpreter to \fBpanic\fR if the memory allocation fails.  If the
+allocation fails, these functions will return NULL.
 .SH KEYWORDS
 alloc, allocation, free, malloc, memory, realloc
diff --git a/doc/StringObj.3 b/doc/StringObj.3
index d195362..23273d0 100644
--- a/doc/StringObj.3
+++ b/doc/StringObj.3
@@ -4,7 +4,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: StringObj.3,v 1.5 1999/06/15 01:16:21 hershey Exp $
+'\" RCS: @(#) $Id: StringObj.3,v 1.6 2000/09/14 18:42:29 ericm Exp $
 '\" 
 .so man.macros
 .TH Tcl_StringObj 3 8.1 Tcl "Tcl Library Procedures"
@@ -71,6 +71,9 @@ void
 void
 \fBTcl_SetObjLength\fR(\fIobjPtr, newLength\fR)
 .sp
+int
+\fBTcl_AttemptSetObjLength\fR(\fIobjPtr, newLength\fR)
+.sp
 Tcl_Obj *
 \fBTcl_ConcatObj\fR(\fIobjc, objv\fR)
 .SH ARGUMENTS
@@ -227,6 +230,16 @@ enlarged in a subsequent call to \fBTcl_SetObjLength\fR without
 reallocating storage.  In all cases \fBTcl_SetObjLength\fR leaves
 a null character at \fIobjPtr->bytes[newLength]\fR.
 .PP
+\fBTcl_AttemptSetObjLength\fR is identical in function to
+\fBTcl_SetObjLength\fR except that if sufficient memory to satisfy the
+request cannot be allocated, it does not cause the Tcl interpreter to
+\fBpanic\fR.  Thus, if \fInewLength\fR is greater than the space
+allocated for the object's string, and there is not enough memory
+available to satisfy the request, \fBTcl_AttemptSetObjLength\fR will take
+no action and return 0 to indicate failure.  If there is enough memory
+to satisfy the request, \fBTcl_AttemptSetObjLength\fR behaves just like
+\fBTcl_SetObjLength\fR and returns 1 to indicate success.
+.PP
 The \fBTcl_ConcatObj\fR function returns a new string object whose
 value is the space-separated concatenation of the string
 representations of all of the objects in the \fIobjv\fR
diff --git a/generic/tcl.decls b/generic/tcl.decls
index e71c6ee..d40d50d 100644
--- a/generic/tcl.decls
+++ b/generic/tcl.decls
@@ -10,7 +10,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 # 
-# RCS: @(#) $Id: tcl.decls,v 1.39 2000/08/25 02:04:27 ericm Exp $
+# RCS: @(#) $Id: tcl.decls,v 1.40 2000/09/14 18:42:29 ericm Exp $
 
 library tcl
 
@@ -1418,6 +1418,22 @@ declare 409 generic {
     void Tcl_UntraceCommand(Tcl_Interp *interp, char *varName, int flags, \
 		Tcl_CommandTraceProc *proc, ClientData clientData)
 }
+declare 410 generic {
+    char * Tcl_AttemptAlloc(unsigned int size)
+}
+declare 411 generic {
+    char * Tcl_AttemptDbCkalloc(unsigned int size, char *file, int line)
+}
+declare 412 generic {
+    char * Tcl_AttemptRealloc(char *ptr, unsigned int size)
+}
+declare 413 generic {
+    char * Tcl_AttemptDbCkrealloc(char *ptr, unsigned int size, char *file, 
+	int line)
+}
+declare 414 generic {
+    int Tcl_AttemptSetObjLength(Tcl_Obj *objPtr, int length)
+}
 
 ##############################################################################
 
diff --git a/generic/tcl.h b/generic/tcl.h
index 22f4f88..5d239e9 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tcl.h,v 1.78 2000/09/06 18:50:15 hobbs Exp $
+ * RCS: @(#) $Id: tcl.h,v 1.79 2000/09/14 18:42:29 ericm Exp $
  */
 
 #ifndef _TCL
@@ -1341,7 +1341,8 @@ typedef int	(Tcl_DriverGetHandleProc) _ANSI_ARGS_((
 #   define ckalloc(x) Tcl_DbCkalloc(x, __FILE__, __LINE__)
 #   define ckfree(x)  Tcl_DbCkfree(x, __FILE__, __LINE__)
 #   define ckrealloc(x,y) Tcl_DbCkrealloc((x), (y),__FILE__, __LINE__)
-
+#   define attemptckalloc(x) Tcl_AttempDbCkalloc(x, __FILE__, __LINE__)
+#   define attemptckrealloc(x,y) Tcl_AttemptDbCkrealloc((x), (y), __FILE__, __LINE__)
 #else /* !TCL_MEM_DEBUG */
 
 /*
@@ -1354,6 +1355,8 @@ typedef int	(Tcl_DriverGetHandleProc) _ANSI_ARGS_((
 #   define ckalloc(x) Tcl_Alloc(x)
 #   define ckfree(x) Tcl_Free(x)
 #   define ckrealloc(x,y) Tcl_Realloc(x,y)
+#   define attemptckalloc(x) Tcl_AttemptAlloc(x)
+#   define attemptckrealloc(x,y) Tcl_AttemptRealloc(x,y)
 #   define Tcl_InitMemory(x)
 #   define Tcl_DumpActiveMemory(x)
 #   define Tcl_ValidateAllMemory(x,y)
diff --git a/generic/tclCkalloc.c b/generic/tclCkalloc.c
index a85a0fd..c0d79e4 100644
--- a/generic/tclCkalloc.c
+++ b/generic/tclCkalloc.c
@@ -13,7 +13,7 @@
  *
  * This code contributed by Karl Lehenbauer and Mark Diekhans
  *
- * RCS: @(#) $Id: tclCkalloc.c,v 1.8 2000/04/27 01:47:01 ericm Exp $
+ * RCS: @(#) $Id: tclCkalloc.c,v 1.9 2000/09/14 18:42:30 ericm Exp $
  */
 
 #include "tclInt.h"
@@ -593,6 +593,8 @@ Tcl_DbCkrealloc(ptr, size, file, line)
 #undef Tcl_Alloc
 #undef Tcl_Free
 #undef Tcl_Realloc
+#undef Tcl_AttemptAlloc
+#undef Tcl_AttemptRealloc
 
 char *
 Tcl_Alloc(size)
@@ -601,6 +603,13 @@ Tcl_Alloc(size)
     return Tcl_DbCkalloc(size, "unknown", 0);
 }
 
+char *
+Tcl_AttemptAlloc(size)
+    unsigned int size;
+{
+    return Tcl_AttemptDbCkalloc(size, "unknown", 0);
+}
+
 void
 Tcl_Free(ptr)
     char *ptr;
@@ -615,6 +624,13 @@ Tcl_Realloc(ptr, size)
 {
     return Tcl_DbCkrealloc(ptr, size, "unknown", 0);
 }
+char *
+Tcl_AttemptRealloc(ptr, size)
+    char *ptr;
+    unsigned int size;
+{
+    return Tcl_AttemptDbCkrealloc(ptr, size, "unknown", 0);
+}
 
 /*
  *----------------------------------------------------------------------
@@ -875,6 +891,38 @@ Tcl_DbCkalloc(size, file, line)
     }
     return result;
 }
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AttemptAlloc --
+ *     Interface to TclpAlloc when TCL_MEM_DEBUG is disabled.  It does not
+ *     check that memory was actually allocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+char *
+Tcl_AttemptAlloc (size)
+    unsigned int size;
+{
+    char *result;
+
+    result = TclpAlloc(size);
+    return result;
+}
+
+char *
+Tcl_AttemptDbCkalloc(size, file, line)
+    unsigned int size;
+    char        *file;
+    int          line;
+{
+    char *result;
+
+    result = (char *) TclpAlloc(size);
+    return result;
+}
 
 
 /*
@@ -923,6 +971,40 @@ Tcl_DbCkrealloc(ptr, size, file, line)
 /*
  *----------------------------------------------------------------------
  *
+ * Tcl_AttemptRealloc --
+ *     Interface to TclpRealloc when TCL_MEM_DEBUG is disabled.  It does 
+ *     not check that memory was actually allocated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+char *
+Tcl_AttemptRealloc(ptr, size)
+    char *ptr;
+    unsigned int size;
+{
+    char *result;
+
+    result = TclpRealloc(ptr, size);
+    return result;
+}
+
+char *
+Tcl_AttemptDbCkrealloc(ptr, size, file, line)
+    char *ptr;
+    unsigned int size;
+    char *file;
+    int line;
+{
+    char *result;
+
+    result = (char *) TclpRealloc(ptr, size);
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tcl_Free --
  *     Interface to TclpFree when TCL_MEM_DEBUG is disabled.  Done here
  *     rather in the macro to keep some modules from being compiled with 
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index fd355df..9b2f9a8 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -8,7 +8,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclDecls.h,v 1.40 2000/08/25 02:04:28 ericm Exp $
+ * RCS: @(#) $Id: tclDecls.h,v 1.41 2000/09/14 18:42:31 ericm Exp $
  */
 
 #ifndef _TCLDECLS
@@ -1283,6 +1283,20 @@ EXTERN void		Tcl_UntraceCommand _ANSI_ARGS_((Tcl_Interp * interp,
 				char * varName, int flags, 
 				Tcl_CommandTraceProc * proc, 
 				ClientData clientData));
+/* 410 */
+EXTERN char *		Tcl_AttemptAlloc _ANSI_ARGS_((unsigned int size));
+/* 411 */
+EXTERN char *		Tcl_AttemptDbCkalloc _ANSI_ARGS_((unsigned int size, 
+				char * file, int line));
+/* 412 */
+EXTERN char *		Tcl_AttemptRealloc _ANSI_ARGS_((char * ptr, 
+				unsigned int size));
+/* 413 */
+EXTERN char *		Tcl_AttemptDbCkrealloc _ANSI_ARGS_((char * ptr, 
+				unsigned int size, char * file, int line));
+/* 414 */
+EXTERN int		Tcl_AttemptSetObjLength _ANSI_ARGS_((
+				Tcl_Obj * objPtr, int length));
 
 typedef struct TclStubHooks {
     struct TclPlatStubs *tclPlatStubs;
@@ -1760,6 +1774,11 @@ typedef struct TclStubs {
     ClientData (*tcl_CommandTraceInfo) _ANSI_ARGS_((Tcl_Interp * interp, char * varName, int flags, Tcl_CommandTraceProc * procPtr, ClientData prevClientData)); /* 407 */
     int (*tcl_TraceCommand) _ANSI_ARGS_((Tcl_Interp * interp, char * varName, int flags, Tcl_CommandTraceProc * proc, ClientData clientData)); /* 408 */
     void (*tcl_UntraceCommand) _ANSI_ARGS_((Tcl_Interp * interp, char * varName, int flags, Tcl_CommandTraceProc * proc, ClientData clientData)); /* 409 */
+    char * (*tcl_AttemptAlloc) _ANSI_ARGS_((unsigned int size)); /* 410 */
+    char * (*tcl_AttemptDbCkalloc) _ANSI_ARGS_((unsigned int size, char * file, int line)); /* 411 */
+    char * (*tcl_AttemptRealloc) _ANSI_ARGS_((char * ptr, unsigned int size)); /* 412 */
+    char * (*tcl_AttemptDbCkrealloc) _ANSI_ARGS_((char * ptr, unsigned int size, char * file, int line)); /* 413 */
+    int (*tcl_AttemptSetObjLength) _ANSI_ARGS_((Tcl_Obj * objPtr, int length)); /* 414 */
 } TclStubs;
 
 #ifdef __cplusplus
@@ -3445,6 +3464,26 @@ extern TclStubs *tclStubsPtr;
 #define Tcl_UntraceCommand \
 	(tclStubsPtr->tcl_UntraceCommand) /* 409 */
 #endif
+#ifndef Tcl_AttemptAlloc
+#define Tcl_AttemptAlloc \
+	(tclStubsPtr->tcl_AttemptAlloc) /* 410 */
+#endif
+#ifndef Tcl_AttemptDbCkalloc
+#define Tcl_AttemptDbCkalloc \
+	(tclStubsPtr->tcl_AttemptDbCkalloc) /* 411 */
+#endif
+#ifndef Tcl_AttemptRealloc
+#define Tcl_AttemptRealloc \
+	(tclStubsPtr->tcl_AttemptRealloc) /* 412 */
+#endif
+#ifndef Tcl_AttemptDbCkrealloc
+#define Tcl_AttemptDbCkrealloc \
+	(tclStubsPtr->tcl_AttemptDbCkrealloc) /* 413 */
+#endif
+#ifndef Tcl_AttemptSetObjLength
+#define Tcl_AttemptSetObjLength \
+	(tclStubsPtr->tcl_AttemptSetObjLength) /* 414 */
+#endif
 
 #endif /* defined(USE_TCL_STUBS) && !defined(USE_TCL_STUB_PROCS) */
 
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index 3bdefbd..a20fa06 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -33,7 +33,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclStringObj.c,v 1.18 2000/08/30 01:43:00 ericm Exp $ */
+ * RCS: @(#) $Id: tclStringObj.c,v 1.19 2000/09/14 18:42:31 ericm Exp $ */
 
 #include "tclInt.h"
 
@@ -113,42 +113,35 @@ typedef struct String {
  *
  * When growing strings (during an append, for example), the following growth
  * algorithm is used:
- *	if (oldSpace + appendLength < TCL_GROWTH_LARGE_STRING) {
- *	    newSpace = 2 * (oldSpace + appendLength)
- *	} else {
- *	    newSpace = (2 * appendLength) + TCL_GROWTH_MIN_ALLOC + oldSpace
- *	}
- *
- * This allows more efficient use of memory for large strings; if the
- * doubling algorithm were used after TCL_GROWTH_LARGE_STRING, the
- * maximum string size in Tcl would be about 1/2 the size of available
- * memory.  With this adaptive algorithm, effectively all of available memory
- * can be allocated.
  *
+ *   Attempt to allocate 2 * (originalLength + appendLength)
+ *   On failure:
+ *	attempt to allocate originalLength + 2*appendLength +
+ *			TCL_GROWTH_MIN_ALLOC 
+ *
+ * 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_GROWTH_MIN_ALLOC 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_GROWTH_MIN_ALLOC is a reasonable size, we can
  * avoid that behavior.
  *
- * We do NOT use TCL_GROWTH_MIN_ALLOC for strings smaller than
- * TCL_GROWTH_LARGE_STRING simply because we want our small strings
- * to stay small; an allocation of TCL_GROWTH_MIN_ALLOC for a string
- * that is only a few bytes long is wasteful.
- *
  * The growth algorithm can be tuned by adjusting the following parameters:
  *
- * TCL_GROWTH_LARGE_STRING	Cutoff point, in bytes, at which to switch
- *				from the doubling algorithm to the adaptive.
- *				algorithm.  Default is 1048576 (1 megabyte)
- * TCL_GROWTH_MIN_ALLOC		Additional space, in bytes, to allocate with
- *				each allocation for strings larger than
- *				TCL_GROWTH_LARGE_STRING.
+ * TCL_GROWTH_MIN_ALLOC		Additional space, in bytes, to allocate when
+ *				the double allocation has failed.
  *				Default is 1024 (1 kilobyte).
  */
-#ifndef TCL_GROWTH_LARGE_STRING
-#define TCL_GROWTH_LARGE_STRING	1048576
-#endif
 #ifndef TCL_GROWTH_MIN_ALLOC
 #define TCL_GROWTH_MIN_ALLOC	1024
 #endif
@@ -715,10 +708,7 @@ Tcl_SetObjLength(objPtr, length)
  	if (objPtr->bytes != tclEmptyStringRep) {
 	    new = (char *) ckrealloc((char *)objPtr->bytes,
 		    (unsigned)(length+1));
- 	} else {
-	    new = NULL;
- 	}
- 	if (new == NULL) {
+	} else {
 	    new = (char *) ckalloc((unsigned) (length+1));
 	    if (objPtr->bytes != NULL && objPtr->length != 0) {
  	    	memcpy((VOID *) new, (VOID *) objPtr->bytes,
@@ -737,6 +727,88 @@ Tcl_SetObjLength(objPtr, length)
 }
 
 /*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AttemptSetObjLength --
+ *
+ *	This procedure changes the length of the string representation
+ *	of an object.  It uses the attempt* (non-panic'ing) memory allocators.
+ *
+ * Results:
+ *	1 if the requested memory was allocated, 0 otherwise.
+ *
+ * Side effects:
+ *	If the size of objPtr's string representation is greater than
+ *	length, then it is reduced to length and a new terminating null
+ *	byte is stored in the strength.  If the length of the string
+ *	representation is greater than length, the storage space is
+ *	reallocated to the given length; a null byte is stored at the
+ *	end, but other bytes past the end of the original string
+ *	representation are undefined.  The object's internal
+ *	representation is changed to "expendable string".
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_AttemptSetObjLength(objPtr, length)
+    register Tcl_Obj *objPtr;	/* Pointer to object.  This object must
+				 * not currently be shared. */
+    register int length;	/* Number of bytes desired for string
+				 * representation of object, not including
+				 * terminating null byte. */
+{
+    char *new;
+    String *stringPtr;
+
+    if (Tcl_IsShared(objPtr)) {
+	panic("Tcl_AttemptSetObjLength called with shared object");
+    }
+    SetStringFromAny(NULL, objPtr);
+        
+    /*
+     * Invalidate the unicode data.
+     */
+
+    stringPtr = GET_STRING(objPtr);
+    stringPtr->numChars = -1;
+    stringPtr->uallocated = 0;
+
+    if (length > (int) stringPtr->allocated) {
+
+	/*
+	 * Not enough space in current string. Reallocate the string
+	 * space and free the old string.
+	 */
+ 	if (objPtr->bytes != tclEmptyStringRep) {
+	    new = (char *) attemptckrealloc((char *)objPtr->bytes,
+		    (unsigned)(length+1));
+	    if (new == NULL) {
+		return 0;
+	    }
+ 	} else {
+	    new = (char *) attemptckalloc((unsigned) (length+1));
+	    if (new == NULL) {
+		return 0;
+	    }
+	    if (objPtr->bytes != NULL && objPtr->length != 0) {
+ 	    	memcpy((VOID *) new, (VOID *) objPtr->bytes,
+ 		    	(size_t) objPtr->length);
+ 	    	Tcl_InvalidateStringRep(objPtr);
+	    }
+	}
+	objPtr->bytes = new;
+	stringPtr->allocated = length;
+    }
+    
+    objPtr->length = length;
+    if ((objPtr->bytes != NULL) && (objPtr->bytes != tclEmptyStringRep)) {
+	objPtr->bytes[length] = 0;
+    }
+    return 1;
+}
+
+/*
  *---------------------------------------------------------------------------
  *
  * TclSetUnicodeObj --
@@ -1016,7 +1088,7 @@ AppendUnicodeToUnicodeRep(objPtr, unicode, appendNumChars)
     Tcl_UniChar *unicode;     /* String to append. */
     int appendNumChars;	      /* Number of chars of "unicode" to append. */
 {
-    String *stringPtr;
+    String *stringPtr, *tmpString;
     size_t numChars;
 
     if (appendNumChars < 0) {
@@ -1034,19 +1106,25 @@ AppendUnicodeToUnicodeRep(objPtr, unicode, appendNumChars)
 
     /*
      * If not enough space has been allocated for the unicode rep,
-     * reallocate the internal rep object with additional space.  See the
-     * "TCL STRING GROWTH ALGORITHM" comment at the top of this file for an
-     * explanation of the growth algorithm.
+     * reallocate the internal rep object with additional space.  First try to
+     * double the required allocation; if that fails, try a more modest
+     * increase.  See the "TCL STRING GROWTH ALGORITHM" comment at the top of
+     * this file for an explanation of this growth algorithm.
      */
 
     numChars = stringPtr->numChars + appendNumChars;
 
     if (numChars >= stringPtr->uallocated) {
- 	stringPtr->uallocated = numChars +
-	    (numChars >= TCL_GROWTH_LARGE_STRING ?
-		    (2 * appendNumChars) + TCL_GROWTH_MIN_ALLOC : numChars);
-	stringPtr = (String *) ckrealloc((char*)stringPtr,
+ 	stringPtr->uallocated = 2 * numChars;
+	tmpString = (String *) attemptckrealloc((char *)stringPtr,
 		STRING_SIZE(stringPtr->uallocated));
+	if (tmpString == NULL) {
+	    stringPtr->uallocated =
+		numChars + appendNumChars + TCL_GROWTH_MIN_ALLOC;
+	    tmpString = (String *) ckrealloc((char *)stringPtr,
+		    STRING_SIZE(stringPtr->uallocated));
+	}
+	stringPtr = tmpString;
 	SET_STRING(objPtr, stringPtr);
     }
 
@@ -1193,14 +1271,16 @@ AppendUtfToUtfRep(objPtr, bytes, numBytes)
 
 	/*
 	 * There isn't currently enough space in the string representation
-	 * so allocate additional space.  See the "TCL STRING GROWTH ALGORITHM"
-	 * comment at the top of this file for an explanation of the growth
-	 * algorithm.
+	 * so allocate additional space.  First, try to double the length
+	 * required.  If that fails, try a more modest allocation.  See the
+	 * "TCL STRING GROWTH ALGORITHM" comment at the top of this file for an
+	 * explanation of this growth algorithm.
 	 */
 
-	Tcl_SetObjLength(objPtr, newLength +
-		(newLength >= TCL_GROWTH_LARGE_STRING ?
-			(2 * numBytes) + TCL_GROWTH_MIN_ALLOC : newLength));
+	if (Tcl_AttemptSetObjLength(objPtr, 2 * newLength) == 0) {
+	    Tcl_SetObjLength(objPtr,
+		    newLength + numBytes + TCL_GROWTH_MIN_ALLOC);
+	}
     } else {
 
 	/*
@@ -1242,7 +1322,7 @@ Tcl_AppendStringsToObjVA (objPtr, argList)
 {
 #define STATIC_LIST_SIZE 16
     String *stringPtr;
-    int newLength, oldLength;
+    int newLength, oldLength, attemptLength;
     register char *string, *dst;
     char *static_list[STATIC_LIST_SIZE];
     char **args = static_list;
@@ -1299,19 +1379,23 @@ Tcl_AppendStringsToObjVA (objPtr, argList)
 	 * 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 the growth algorithm described in
-	 * the "TCL STRING GROWTH ALGORITHM" comment at the top of this file is
-	 * used to determine how much memory to allocate.  Otherwise, exactly
-	 * enough memory is allocated.
+	 * doing a series of appends) then try to allocate extra space to
+	 * accomodate future growth: first try to double the required memory;
+	 * if that fails, try a more modest allocation.  See the "TCL STRING
+	 * GROWTH ALGORITHM" comment at the top of this file for an explanation
+	 * of this growth algorithm.  Otherwise, if the current string
+	 * representation is empty, exactly enough memory is allocated.
 	 */
 
 	if (oldLength == 0) {
 	    Tcl_SetObjLength(objPtr, newLength);
-	} else if (oldLength < TCL_GROWTH_LARGE_STRING) {
-	    Tcl_SetObjLength(objPtr, 2 * (oldLength + newLength));
 	} else {
-	    Tcl_SetObjLength(objPtr,
-		    oldLength + (2 * newLength) + TCL_GROWTH_MIN_ALLOC);
+	    attemptLength = 2 * (oldLength + newLength);
+	    if (Tcl_AttemptSetObjLength(objPtr, attemptLength) == 0) {
+		attemptLength = oldLength + (2 * newLength) +
+		    TCL_GROWTH_MIN_ALLOC;
+		Tcl_SetObjLength(objPtr, attemptLength);
+	    }
 	}
     }
 
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index c927969..dbd5372 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -8,7 +8,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclStubInit.c,v 1.43 2000/08/25 02:04:29 ericm Exp $
+ * RCS: @(#) $Id: tclStubInit.c,v 1.44 2000/09/14 18:42:32 ericm Exp $
  */
 
 #include "tclInt.h"
@@ -812,6 +812,11 @@ TclStubs tclStubs = {
     Tcl_CommandTraceInfo, /* 407 */
     Tcl_TraceCommand, /* 408 */
     Tcl_UntraceCommand, /* 409 */
+    Tcl_AttemptAlloc, /* 410 */
+    Tcl_AttemptDbCkalloc, /* 411 */
+    Tcl_AttemptRealloc, /* 412 */
+    Tcl_AttemptDbCkrealloc, /* 413 */
+    Tcl_AttemptSetObjLength, /* 414 */
 };
 
 /* !END!: Do not edit above this line. */