text: /*
   * tclStringObj.c --
   *
   *	This file contains functions that implement string operations on Tcl
   *	objects. Some string operations work with UTF strings and others
   *	require Unicode format. Functions that require knowledge of the width
   *	of each character, such as indexing, operate on Unicode data.
   *
   *	A Unicode string is an internationalized string. Conceptually, a
   *	Unicode string is an array of 16-bit quantities organized as a
   *	sequence of properly formed UTF-8 characters. There is a one-to-one
   *	map between Unicode and UTF characters. Because Unicode characters
   *	have a fixed width, operations such as indexing operate on Unicode
   *	data. The String object is optimized for the case where each UTF char
   *	in a string is only one byte. In this case, we store the value of
   *	numChars, but we don't store the Unicode data (unless Tcl_GetUnicode
   *	is explicitly called).
   *
   *	The String object type stores one or both formats. The default
   *	behavior is to store UTF. Once Unicode is calculated by a function, it
   *	is stored in the internal rep for future access (without an additional
   *	O(n) cost).
   *
   *	To allow many appends to be done to an object without constantly
   *	reallocating the space for the string or Unicode representation, we
   *	allocate double the space for the string or Unicode and use the
   *	internal representation to keep track of how much space is used vs.
   *	allocated.
   *
   * Copyright (c) 1995-1997 Sun Microsystems, Inc.
   * Copyright (c) 1999 by Scriptics Corporation.
   *
   * See the file "license.terms" for information on usage and redistribution of
   * this file, and for a DISCLAIMER OF ALL WARRANTIES.
   */
  
  #include "tclInt.h"
  #include "tommath.h"
  #include "tclStringRep.h"
  
  /*
   * Set COMPAT to 1 to restore the shimmering patterns to those of Tcl 8.5.
   * This is an escape hatch in case the changes have some unexpected unwelcome
   * impact on performance. If things go well, this mechanism can go away when
   * post-8.6 development begins.
   */
  
  #define COMPAT 0
  
  /*
   * Prototypes for functions defined later in this file:
   */
  
  static void		AppendPrintfToObjVA(Tcl_Obj *objPtr,
  			    const char *format, va_list argList);
  static void		AppendUnicodeToUnicodeRep(Tcl_Obj *objPtr,
  			    const Tcl_UniChar *unicode, int appendNumChars);
  static void		AppendUnicodeToUtfRep(Tcl_Obj *objPtr,
  			    const Tcl_UniChar *unicode, int numChars);
  static void		AppendUtfToUnicodeRep(Tcl_Obj *objPtr,
  			    const char *bytes, int numBytes);
  static void		AppendUtfToUtfRep(Tcl_Obj *objPtr,
  			    const char *bytes, int numBytes);
  static void		DupStringInternalRep(Tcl_Obj *objPtr,
  			    Tcl_Obj *copyPtr);
  static int		ExtendStringRepWithUnicode(Tcl_Obj *objPtr,
  			    const Tcl_UniChar *unicode, int numChars);
  static void		ExtendUnicodeRepWithString(Tcl_Obj *objPtr,
  			    const char *bytes, int numBytes,
  			    int numAppendChars);
  static void		FillUnicodeRep(Tcl_Obj *objPtr);
  static void		FreeStringInternalRep(Tcl_Obj *objPtr);
  static void		GrowStringBuffer(Tcl_Obj *objPtr, int needed, int flag);
  static void		GrowUnicodeBuffer(Tcl_Obj *objPtr, int needed);
  static int		SetStringFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr);
  static void		SetUnicodeObj(Tcl_Obj *objPtr,
  			    const Tcl_UniChar *unicode, int numChars);
  static int		UnicodeLength(const Tcl_UniChar *unicode);
  static void		UpdateStringOfString(Tcl_Obj *objPtr);
  
  /*
   * The structure below defines the string Tcl object type by means of
   * functions that can be invoked by generic object code.
   */
  
  const Tcl_ObjType tclStringType = {
      "string",			/* name */
      FreeStringInternalRep,	/* freeIntRepPro */
      DupStringInternalRep,	/* dupIntRepProc */
      UpdateStringOfString,	/* updateStringProc */
      SetStringFromAny		/* setFromAnyProc */
  };
  
  /*
   * 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)
  {
      /*
       * Pre-conditions:
       *	objPtr->typePtr == &tclStringType
       *	needed > stringPtr->allocated
       *	flag || objPtr->bytes != NULL
       */
  
      String *stringPtr = GET_STRING(objPtr);
      char *ptr = NULL;
      int attempt;
  
      if (objPtr->bytes == tclEmptyStringRep) {
  	objPtr->bytes = NULL;
      }
      if (flag == 0 || stringPtr->allocated > 0) {
  	attempt = 2 * needed;
  	if (attempt >= 0) {
  	    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 = 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) {
  	/*
  	 * First allocation - just big enough; or last chance fallback.
  	 */
  
  	attempt = needed;
  	ptr = ckrealloc(objPtr->bytes, attempt + 1);
      }
      objPtr->bytes = ptr;
      stringPtr->allocated = attempt;
  }
  
  static void
  GrowUnicodeBuffer(
      Tcl_Obj *objPtr,
      int needed)
  {
      /*
       * Pre-conditions:
       *	objPtr->typePtr == &tclStringType
       *	needed > stringPtr->maxChars
       *	needed < STRING_MAXCHARS
       */
  
      String *ptr = NULL, *stringPtr = GET_STRING(objPtr);
      int attempt;
  
      if (stringPtr->maxChars > 0) {
  	/*
  	 * Subsequent appends - apply the growth algorithm.
  	 */
  
  	attempt = 2 * needed;
  	if (attempt >= 0 && attempt <= STRING_MAXCHARS) {
  	    ptr = stringAttemptRealloc(stringPtr, attempt);
  	}
  	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) {
  	/*
  	 * First allocation - just big enough; or last chance fallback.
  	 */
  
  	attempt = needed;
  	ptr = stringRealloc(stringPtr, attempt);
      }
      stringPtr = ptr;
      stringPtr->maxChars = attempt;
      SET_STRING(objPtr, stringPtr);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_NewStringObj --
   *
   *	This function is normally called when not debugging: i.e., when
   *	TCL_MEM_DEBUG is not defined. It creates a new string object and
   *	initializes it from the byte pointer and length arguments.
   *
   *	When TCL_MEM_DEBUG is defined, this function just returns the result
   *	of calling the debugging version Tcl_DbNewStringObj.
   *
   * Results:
   *	A newly created string object is returned that has ref count zero.
   *
   * Side effects:
   *	The new object's internal string representation will be set to a copy
   *	of the length bytes starting at "bytes". If "length" is negative, use
   *	bytes up to the first NUL byte; i.e., assume "bytes" points to a
   *	C-style NUL-terminated string. The object's type is set to NULL. An
   *	extra NUL is added to the end of the new object's byte array.
   *
   *----------------------------------------------------------------------
   */
  
  #ifdef TCL_MEM_DEBUG
  #undef Tcl_NewStringObj
  Tcl_Obj *
  Tcl_NewStringObj(
      const char *bytes,		/* Points to the first of the length bytes
  				 * used to initialize the new object. */
      int length)			/* The number of bytes to copy from "bytes"
  				 * when initializing the new object. If
  				 * negative, use bytes up to the first NUL
  				 * byte. */
  {
      return Tcl_DbNewStringObj(bytes, length, "unknown", 0);
  }
  #else /* if not TCL_MEM_DEBUG */
  Tcl_Obj *
  Tcl_NewStringObj(
      const char *bytes,		/* Points to the first of the length bytes
  				 * used to initialize the new object. */
      int length)			/* The number of bytes to copy from "bytes"
  				 * when initializing the new object. If
  				 * negative, use bytes up to the first NUL
  				 * byte. */
  {
      Tcl_Obj *objPtr;
  
      if (length < 0) {
  	length = (bytes? strlen(bytes) : 0);
      }
      TclNewStringObj(objPtr, bytes, length);
      return objPtr;
  }
  #endif /* TCL_MEM_DEBUG */
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_DbNewStringObj --
   *
   *	This function is normally called when debugging: i.e., when
   *	TCL_MEM_DEBUG is defined. It creates new string objects. It is the
   *	same as the Tcl_NewStringObj function above except that it calls
   *	Tcl_DbCkalloc directly with the file name and line number from its
   *	caller. This simplifies debugging since then the [memory active]
   *	command will report the correct file name and line number when
   *	reporting objects that haven't been freed.
   *
   *	When TCL_MEM_DEBUG is not defined, this function just returns the
   *	result of calling Tcl_NewStringObj.
   *
   * Results:
   *	A newly created string object is returned that has ref count zero.
   *
   * Side effects:
   *	The new object's internal string representation will be set to a copy
   *	of the length bytes starting at "bytes". If "length" is negative, use
   *	bytes up to the first NUL byte; i.e., assume "bytes" points to a
   *	C-style NUL-terminated string. The object's type is set to NULL. An
   *	extra NUL is added to the end of the new object's byte array.
   *
   *----------------------------------------------------------------------
   */
  
  #ifdef TCL_MEM_DEBUG
  Tcl_Obj *
  Tcl_DbNewStringObj(
      const char *bytes,		/* Points to the first of the length bytes
  				 * used to initialize the new object. */
      int length,			/* The number of bytes to copy from "bytes"
  				 * when initializing the new object. If
  				 * negative, use bytes up to the first NUL
  				 * byte. */
      const char *file,		/* The name of the source file calling this
  				 * function; used for debugging. */
      int line)			/* Line number in the source file; used for
  				 * debugging. */
  {
      Tcl_Obj *objPtr;
  
      if (length < 0) {
  	length = (bytes? strlen(bytes) : 0);
      }
      TclDbNewObj(objPtr, file, line);
      TclInitStringRep(objPtr, bytes, length);
      return objPtr;
  }
  #else /* if not TCL_MEM_DEBUG */
  Tcl_Obj *
  Tcl_DbNewStringObj(
      const char *bytes,		/* Points to the first of the length bytes
  				 * used to initialize the new object. */
      int length,			/* The number of bytes to copy from "bytes"
  				 * when initializing the new object. If
  				 * negative, use bytes up to the first NUL
  				 * byte. */
      const char *file,		/* The name of the source file calling this
  				 * function; used for debugging. */
      int line)			/* Line number in the source file; used for
  				 * debugging. */
  {
      return Tcl_NewStringObj(bytes, length);
  }
  #endif /* TCL_MEM_DEBUG */
  
  /*
   *---------------------------------------------------------------------------
   *
   * Tcl_NewUnicodeObj --
   *
   *	This function is creates a new String object and initializes it from
   *	the given Unicode String. If the Utf String is the same size as the
   *	Unicode string, don't duplicate the data.
   *
   * Results:
   *	The newly created object is returned. This object will have no initial
   *	string representation. The returned object has a ref count of 0.
   *
   * Side effects:
   *	Memory allocated for new object and copy of Unicode argument.
   *
   *---------------------------------------------------------------------------
   */
  
  Tcl_Obj *
  Tcl_NewUnicodeObj(
      const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
  				 * new object. */
      int numChars)		/* Number of characters in the unicode
  				 * string. */
  {
      Tcl_Obj *objPtr;
  
      TclNewObj(objPtr);
      SetUnicodeObj(objPtr, unicode, numChars);
      return objPtr;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_GetCharLength --
   *
   *	Get the length of the Unicode string from the Tcl object.
   *
   * Results:
   *	Pointer to unicode string representing the unicode object.
   *
   * Side effects:
   *	Frees old internal rep. Allocates memory for new "String" internal
   *	rep.
   *
   *----------------------------------------------------------------------
   */
  
  int
  Tcl_GetCharLength(
      Tcl_Obj *objPtr)		/* The String object to get the num chars
  				 * of. */
  {
      String *stringPtr;
      int numChars;
  
      /*
       * Optimize the case where we're really dealing with a bytearray object;
       * we don't need to convert to a string to perform the get-length operation.
       *
       * NOTE that we do not need the bytearray to be "pure".  A ByteArray value
       * with a string rep cannot be trusted to represent the same value as the
       * string rep, but it *can* be trusted to have the same character length
       * as the string rep, which is all this routine cares about.
       */
  
      if (objPtr->typePtr == &tclByteArrayType) {
  	int length;
  
  	(void) Tcl_GetByteArrayFromObj(objPtr, &length);
  	return length;
      }
  
      /*
       * OK, need to work with the object as a string.
       */
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
      numChars = stringPtr->numChars;
  
      /*
       * If numChars is unknown, compute it.
       */
  
      if (numChars == -1) {
  	TclNumUtfChars(numChars, objPtr->bytes, objPtr->length);
  	stringPtr->numChars = numChars;
  
  #if COMPAT
  	if (numChars < objPtr->length) {
  	    /*
  	     * Since we've just computed the number of chars, and not all UTF
  	     * chars are 1-byte long, go ahead and populate the unicode
  	     * string.
  	     */
  
  	    FillUnicodeRep(objPtr);
  	}
  #endif
      }
      return numChars;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_GetUniChar --
   *
   *	Get the index'th Unicode character from the String object. The index
   *	is assumed to be in the appropriate range.
   *
   * Results:
   *	Returns the index'th Unicode character in the Object.
   *
   * Side effects:
   *	Fills unichar with the index'th Unicode character.
   *
   *----------------------------------------------------------------------
   */
  
  Tcl_UniChar
  Tcl_GetUniChar(
      Tcl_Obj *objPtr,		/* The object to get the Unicode charater
  				 * from. */
      int index)			/* Get the index'th Unicode character. */
  {
      String *stringPtr;
  
      /*
       * Optimize the case where we're really dealing with a bytearray object
       * without string representation; we don't need to convert to a string to
       * perform the indexing operation.
       */
  
      if (TclIsPureByteArray(objPtr)) {
  	unsigned char *bytes = Tcl_GetByteArrayFromObj(objPtr, NULL);
  
  	return (Tcl_UniChar) bytes[index];
      }
  
      /*
       * OK, need to work with the object as a string.
       */
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (stringPtr->hasUnicode == 0) {
  	/*
  	 * If numChars is unknown, compute it.
  	 */
  
  	if (stringPtr->numChars == -1) {
  	    TclNumUtfChars(stringPtr->numChars, objPtr->bytes, objPtr->length);
  	}
  	if (stringPtr->numChars == objPtr->length) {
  	    return (Tcl_UniChar) objPtr->bytes[index];
  	}
  	FillUnicodeRep(objPtr);
  	stringPtr = GET_STRING(objPtr);
      }
      return stringPtr->unicode[index];
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_GetUnicode --
   *
   *	Get the Unicode form of the String object. If the object is not
   *	already a String object, it will be converted to one. If the String
   *	object does not have a Unicode rep, then one is create from the UTF
   *	string format.
   *
   * Results:
   *	Returns a pointer to the object's internal Unicode string.
   *
   * Side effects:
   *	Converts the object to have the String internal rep.
   *
   *----------------------------------------------------------------------
   */
  
  Tcl_UniChar *
  Tcl_GetUnicode(
      Tcl_Obj *objPtr)		/* The object to find the unicode string
  				 * for. */
  {
      return Tcl_GetUnicodeFromObj(objPtr, NULL);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_GetUnicodeFromObj --
   *
   *	Get the Unicode form of the String object with length. If the object
   *	is not already a String object, it will be converted to one. If the
   *	String object does not have a Unicode rep, then one is create from the
   *	UTF string format.
   *
   * Results:
   *	Returns a pointer to the object's internal Unicode string.
   *
   * Side effects:
   *	Converts the object to have the String internal rep.
   *
   *----------------------------------------------------------------------
   */
  
  Tcl_UniChar *
  Tcl_GetUnicodeFromObj(
      Tcl_Obj *objPtr,		/* The object to find the unicode string
  				 * for. */
      int *lengthPtr)		/* If non-NULL, the location where the string
  				 * rep's unichar length should be stored. If
  				 * NULL, no length is stored. */
  {
      String *stringPtr;
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (stringPtr->hasUnicode == 0) {
  	FillUnicodeRep(objPtr);
  	stringPtr = GET_STRING(objPtr);
      }
  
      if (lengthPtr != NULL) {
  	*lengthPtr = stringPtr->numChars;
      }
      return stringPtr->unicode;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_GetRange --
   *
   *	Create a Tcl Object that contains the chars between first and last of
   *	the object indicated by "objPtr". If the object is not already a
   *	String object, convert it to one. The first and last indices are
   *	assumed to be in the appropriate range.
   *
   * Results:
   *	Returns a new Tcl Object of the String type.
   *
   * Side effects:
   *	Changes the internal rep of "objPtr" to the String type.
   *
   *----------------------------------------------------------------------
   */
  
  Tcl_Obj *
  Tcl_GetRange(
      Tcl_Obj *objPtr,		/* The Tcl object to find the range of. */
      int first,			/* First index of the range. */
      int last)			/* Last index of the range. */
  {
      Tcl_Obj *newObjPtr;		/* The Tcl object to find the range of. */
      String *stringPtr;
  
      /*
       * Optimize the case where we're really dealing with a bytearray object
       * without string representation; we don't need to convert to a string to
       * perform the substring operation.
       */
  
      if (TclIsPureByteArray(objPtr)) {
  	unsigned char *bytes = Tcl_GetByteArrayFromObj(objPtr, NULL);
  
  	return Tcl_NewByteArrayObj(bytes+first, last-first+1);
      }
  
      /*
       * OK, need to work with the object as a string.
       */
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (stringPtr->hasUnicode == 0) {
  	/*
  	 * If numChars is unknown, compute it.
  	 */
  
  	if (stringPtr->numChars == -1) {
  	    TclNumUtfChars(stringPtr->numChars, objPtr->bytes, objPtr->length);
  	}
  	if (stringPtr->numChars == objPtr->length) {
  	    newObjPtr = Tcl_NewStringObj(objPtr->bytes + first, last-first+1);
  
  	    /*
  	     * Since we know the char length of the result, store it.
  	     */
  
  	    SetStringFromAny(NULL, newObjPtr);
  	    stringPtr = GET_STRING(newObjPtr);
  	    stringPtr->numChars = newObjPtr->length;
  	    return newObjPtr;
  	}
  	FillUnicodeRep(objPtr);
  	stringPtr = GET_STRING(objPtr);
      }
  
      return Tcl_NewUnicodeObj(stringPtr->unicode + first, last-first+1);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_SetStringObj --
   *
   *	Modify an object to hold a string that is a copy of the bytes
   *	indicated by the byte pointer and length arguments.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	The object's string representation will be set to a copy of the
   *	"length" bytes starting at "bytes". If "length" is negative, use bytes
   *	up to the first NUL byte; i.e., assume "bytes" points to a C-style
   *	NUL-terminated string. The object's old string and internal
   *	representations are freed and the object's type is set NULL.
   *
   *----------------------------------------------------------------------
   */
  
  void
  Tcl_SetStringObj(
      Tcl_Obj *objPtr,		/* Object whose internal rep to init. */
      const char *bytes,		/* Points to the first of the length bytes
  				 * used to initialize the object. */
      int length)			/* The number of bytes to copy from "bytes"
  				 * when initializing the object. If negative,
  				 * use bytes up to the first NUL byte.*/
  {
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_SetStringObj");
      }
  
      /*
       * Set the type to NULL and free any internal rep for the old type.
       */
  
      TclFreeIntRep(objPtr);
  
      /*
       * Free any old string rep, then set the string rep to a copy of the
       * length bytes starting at "bytes".
       */
  
      TclInvalidateStringRep(objPtr);
      if (length < 0) {
  	length = (bytes? strlen(bytes) : 0);
      }
      TclInitStringRep(objPtr, bytes, length);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_SetObjLength --
   *
   *	This function changes the length of the string representation of an
   *	object.
   *
   * Results:
   *	None.
   *
   * 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".
   *
   *----------------------------------------------------------------------
   */
  
  void
  Tcl_SetObjLength(
      Tcl_Obj *objPtr,		/* Pointer to object. This object must not
  				 * currently be shared. */
      int length)			/* Number of bytes desired for string
  				 * representation of object, not including
  				 * terminating null byte. */
  {
      String *stringPtr;
  
      if (length < 0) {
  	/*
  	 * Setting to a negative length is nonsense. This is probably the
  	 * result of overflowing the signed integer range.
  	 */
  
  	Tcl_Panic("Tcl_SetObjLength: negative length requested: "
  		"%d (integer overflow?)", length);
      }
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_SetObjLength");
      }
  
      if (objPtr->bytes && objPtr->length == length) {
  	return;
      }
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (objPtr->bytes != NULL) {
  	/*
  	 * Change length of an existing string rep.
  	 */
  	if (length > stringPtr->allocated) {
  	    /*
  	     * Need to enlarge the buffer.
  	     */
  	    if (objPtr->bytes == tclEmptyStringRep) {
  		objPtr->bytes = ckalloc(length + 1);
  	    } else {
  		objPtr->bytes = ckrealloc(objPtr->bytes, length + 1);
  	    }
  	    stringPtr->allocated = length;
  	}
  
  	objPtr->length = length;
  	objPtr->bytes[length] = 0;
  
  	/*
  	 * Invalidate the unicode data.
  	 */
  
  	stringPtr->numChars = -1;
  	stringPtr->hasUnicode = 0;
      } else {
  	/*
  	 * Changing length of pure unicode string.
  	 */
  
  	stringCheckLimits(length);
  	if (length > stringPtr->maxChars) {
  	    stringPtr = stringRealloc(stringPtr, length);
  	    SET_STRING(objPtr, stringPtr);
  	    stringPtr->maxChars = length;
  	}
  
  	/*
  	 * Mark the new end of the unicode string
  	 */
  
  	stringPtr->numChars = length;
  	stringPtr->unicode[length] = 0;
  	stringPtr->hasUnicode = 1;
  
  	/*
  	 * Can only get here when objPtr->bytes == NULL. No need to invalidate
  	 * the string rep.
  	 */
      }
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AttemptSetObjLength --
   *
   *	This function 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(
      Tcl_Obj *objPtr,		/* Pointer to object. This object must not
  				 * currently be shared. */
      int length)			/* Number of bytes desired for string
  				 * representation of object, not including
  				 * terminating null byte. */
  {
      String *stringPtr;
  
      if (length < 0) {
  	/*
  	 * Setting to a negative length is nonsense. This is probably the
  	 * result of overflowing the signed integer range.
  	 */
  
  	return 0;
      }
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_AttemptSetObjLength");
      }
      if (objPtr->bytes && objPtr->length == length) {
  	return 1;
      }
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (objPtr->bytes != NULL) {
  	/*
  	 * Change length of an existing string rep.
  	 */
  	if (length > stringPtr->allocated) {
  	    /*
  	     * Need to enlarge the buffer.
  	     */
  
  	    char *newBytes;
  
  	    if (objPtr->bytes == tclEmptyStringRep) {
  		newBytes = attemptckalloc(length + 1);
  	    } else {
  		newBytes = attemptckrealloc(objPtr->bytes, length + 1);
  	    }
  	    if (newBytes == NULL) {
  		return 0;
  	    }
  	    objPtr->bytes = newBytes;
  	    stringPtr->allocated = length;
  	}
  
  	objPtr->length = length;
  	objPtr->bytes[length] = 0;
  
  	/*
  	 * Invalidate the unicode data.
  	 */
  
  	stringPtr->numChars = -1;
  	stringPtr->hasUnicode = 0;
      } else {
  	/*
  	 * Changing length of pure unicode string.
  	 */
  
  	if (length > STRING_MAXCHARS) {
  	    return 0;
  	}
  	if (length > stringPtr->maxChars) {
  	    stringPtr = stringAttemptRealloc(stringPtr, length);
  	    if (stringPtr == NULL) {
  		return 0;
  	    }
  	    SET_STRING(objPtr, stringPtr);
  	    stringPtr->maxChars = length;
  	}
  
  	/*
  	 * Mark the new end of the unicode string.
  	 */
  
  	stringPtr->unicode[length] = 0;
  	stringPtr->numChars = length;
  	stringPtr->hasUnicode = 1;
  
  	/*
  	 * Can only get here when objPtr->bytes == NULL. No need to invalidate
  	 * the string rep.
  	 */
      }
      return 1;
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * Tcl_SetUnicodeObj --
   *
   *	Modify an object to hold the Unicode string indicated by "unicode".
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	Memory allocated for new "String" internal rep.
   *
   *---------------------------------------------------------------------------
   */
  
  void
  Tcl_SetUnicodeObj(
      Tcl_Obj *objPtr,		/* The object to set the string of. */
      const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
  				 * object. */
      int numChars)		/* Number of characters in the unicode
  				 * string. */
  {
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_SetUnicodeObj");
      }
      TclFreeIntRep(objPtr);
      SetUnicodeObj(objPtr, unicode, numChars);
  }
  
  static int
  UnicodeLength(
      const Tcl_UniChar *unicode)
  {
      int numChars = 0;
  
      if (unicode) {
  	while (numChars >= 0 && unicode[numChars] != 0) {
  	    numChars++;
  	}
      }
      stringCheckLimits(numChars);
      return numChars;
  }
  
  static void
  SetUnicodeObj(
      Tcl_Obj *objPtr,		/* The object to set the string of. */
      const Tcl_UniChar *unicode,	/* The unicode string used to initialize the
  				 * object. */
      int numChars)		/* Number of characters in the unicode
  				 * string. */
  {
      String *stringPtr;
  
      if (numChars < 0) {
  	numChars = UnicodeLength(unicode);
      }
  
      /*
       * Allocate enough space for the String structure + Unicode string.
       */
  
      stringCheckLimits(numChars);
      stringPtr = stringAlloc(numChars);
      SET_STRING(objPtr, stringPtr);
      objPtr->typePtr = &tclStringType;
  
      stringPtr->maxChars = numChars;
      memcpy(stringPtr->unicode, unicode, numChars * sizeof(Tcl_UniChar));
      stringPtr->unicode[numChars] = 0;
      stringPtr->numChars = numChars;
      stringPtr->hasUnicode = 1;
  
      TclInvalidateStringRep(objPtr);
      stringPtr->allocated = 0;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendLimitedToObj --
   *
   *	This function appends a limited number of bytes from a sequence of
   *	bytes to an object, marking any limitation with an ellipsis.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	The bytes at *bytes are appended to the string representation of
   *	objPtr.
   *
   *----------------------------------------------------------------------
   */
  
  void
  Tcl_AppendLimitedToObj(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const char *bytes,		/* Points to the bytes to append to the
  				 * object. */
      int length,			/* The number of bytes available to be
  				 * appended from "bytes". If < 0, then all
  				 * bytes up to a NUL byte are available. */
      int limit,			/* The maximum number of bytes to append to
  				 * the object. */
      const char *ellipsis)	/* Ellipsis marker string, appended to the
  				 * object to indicate not all available bytes
  				 * at "bytes" were appended. */
  {
      String *stringPtr;
      int toCopy = 0;
  
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_AppendLimitedToObj");
      }
  
      if (length < 0) {
  	length = (bytes ? strlen(bytes) : 0);
      }
      if (length == 0) {
  	return;
      }
  
      if (length <= limit) {
  	toCopy = length;
      } else {
  	if (ellipsis == NULL) {
  	    ellipsis = "...";
  	}
  	toCopy = (bytes == NULL) ? limit
  		: Tcl_UtfPrev(bytes+limit+1-strlen(ellipsis), bytes) - bytes;
      }
  
      /*
       * If objPtr has a valid Unicode rep, then append the Unicode conversion
       * of "bytes" to the objPtr's Unicode rep, otherwise append "bytes" to
       * objPtr's string rep.
       */
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (stringPtr->hasUnicode && stringPtr->numChars > 0) {
  	AppendUtfToUnicodeRep(objPtr, bytes, toCopy);
      } else {
  	AppendUtfToUtfRep(objPtr, bytes, toCopy);
      }
  
      if (length <= limit) {
  	return;
      }
  
      stringPtr = GET_STRING(objPtr);
      if (stringPtr->hasUnicode && stringPtr->numChars > 0) {
  	AppendUtfToUnicodeRep(objPtr, ellipsis, strlen(ellipsis));
      } else {
  	AppendUtfToUtfRep(objPtr, ellipsis, strlen(ellipsis));
      }
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendToObj --
   *
   *	This function 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(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const char *bytes,		/* Points to the bytes to append to the
  				 * object. */
      int length)			/* The number of bytes to append from "bytes".
  				 * If < 0, then append all bytes up to NUL
  				 * byte. */
  {
      Tcl_AppendLimitedToObj(objPtr, bytes, length, INT_MAX, NULL);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendUnicodeToObj --
   *
   *	This function appends a Unicode string to an object in the most
   *	efficient manner possible. Length must be >= 0.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	Invalidates the string rep and creates a new Unicode string.
   *
   *----------------------------------------------------------------------
   */
  
  void
  Tcl_AppendUnicodeToObj(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const Tcl_UniChar *unicode,	/* The unicode string to append to the
  				 * object. */
      int length)			/* Number of chars in "unicode". */
  {
      String *stringPtr;
  
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_AppendUnicodeToObj");
      }
  
      if (length == 0) {
  	return;
      }
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      /*
       * If objPtr has a valid Unicode rep, then append the "unicode" to the
       * objPtr's Unicode rep, otherwise the UTF conversion of "unicode" to
       * objPtr's string rep.
       */
  
      if (stringPtr->hasUnicode
  #if COMPAT
  		&& stringPtr->numChars > 0
  #endif
  	    ) {
  	AppendUnicodeToUnicodeRep(objPtr, unicode, length);
      } else {
  	AppendUnicodeToUtfRep(objPtr, unicode, length);
      }
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendObjToObj --
   *
   *	This function appends the string rep of one object to another.
   *	"objPtr" cannot be a shared object.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	The string rep of appendObjPtr is appended to the string
   *	representation of objPtr.
   *	IMPORTANT: This routine does not and MUST NOT shimmer appendObjPtr.
   *	Callers are counting on that.
   *
   *----------------------------------------------------------------------
   */
  
  void
  Tcl_AppendObjToObj(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      Tcl_Obj *appendObjPtr)	/* Object to append. */
  {
      String *stringPtr;
      int length, numChars, appendNumChars = -1;
      const char *bytes;
  
      /*
       * Special case: second object is standard-empty is fast case. We know
       * that appending nothing to anything leaves that starting anything...
       */
  
      if (appendObjPtr->bytes == tclEmptyStringRep) {
  	return;
      }
  
      /*
       * Handle append of one bytearray object to another as a special case.
       * Note that we only do this when the objects don't have string reps; if
       * it did, then appending the byte arrays together could well lose
       * information; this is a special-case optimization only.
       */
  
      if ((TclIsPureByteArray(objPtr) || objPtr->bytes == tclEmptyStringRep)
  	    && TclIsPureByteArray(appendObjPtr)) {
  
  	/*
  	 * You might expect the code here to be
  	 *
  	 *  bytes = Tcl_GetByteArrayFromObj(appendObjPtr, &length);
  	 *  TclAppendBytesToByteArray(objPtr, bytes, length);
  	 *
  	 * and essentially all of the time that would be fine.  However,
  	 * it would run into trouble in the case where objPtr and
  	 * appendObjPtr point to the same thing.  That may never be a
  	 * good idea.  It seems to violate Copy On Write, and we don't
  	 * have any tests for the situation, since making any Tcl commands
  	 * that call Tcl_AppendObjToObj() do that appears impossible
  	 * (They honor Copy On Write!).  For the sake of extensions that
  	 * go off into that realm, though, here's a more complex approach
  	 * that can handle all the cases.
  	 */
  
  	/* Get lengths */
  	int lengthSrc;
  
  	(void) Tcl_GetByteArrayFromObj(objPtr, &length);
  	(void) Tcl_GetByteArrayFromObj(appendObjPtr, &lengthSrc);
  
  	/* Grow buffer enough for the append */
  	TclAppendBytesToByteArray(objPtr, NULL, lengthSrc);
  
  	/* Reset objPtr back to the original value */
  	Tcl_SetByteArrayLength(objPtr, length);
  
  	/*
  	 * Now do the append knowing that buffer growth cannot cause
  	 * any trouble.
  	 */
  
  	TclAppendBytesToByteArray(objPtr,
  		Tcl_GetByteArrayFromObj(appendObjPtr, NULL), lengthSrc);
  	return;
      }
  
      /*
       * Must append as strings.
       */
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      /*
       * If objPtr has a valid Unicode rep, then get a Unicode string from
       * appendObjPtr and append it.
       */
  
      if (stringPtr->hasUnicode
  #if COMPAT
  		&& stringPtr->numChars > 0
  #endif
  	    ) {
  	/*
  	 * If appendObjPtr is not of the "String" type, don't convert it.
  	 */
  
  	if (appendObjPtr->typePtr == &tclStringType) {
  	    Tcl_UniChar *unicode =
  		    Tcl_GetUnicodeFromObj(appendObjPtr, &numChars);
  
  	    AppendUnicodeToUnicodeRep(objPtr, unicode, numChars);
  	} else {
  	    bytes = TclGetStringFromObj(appendObjPtr, &length);
  	    AppendUtfToUnicodeRep(objPtr, bytes, length);
  	}
  	return;
      }
  
      /*
       * Append to objPtr's UTF string rep. If we know the number of characters
       * in both objects before appending, then set the combined number of
       * characters in the final (appended-to) object.
       */
  
      bytes = TclGetStringFromObj(appendObjPtr, &length);
  
      numChars = stringPtr->numChars;
      if ((numChars >= 0) && (appendObjPtr->typePtr == &tclStringType)) {
  	String *appendStringPtr = GET_STRING(appendObjPtr);
  	appendNumChars = appendStringPtr->numChars;
      }
  
      AppendUtfToUtfRep(objPtr, bytes, length);
  
      if (numChars >= 0 && appendNumChars >= 0
  #if COMPAT
  		&& appendNumChars == length
  #endif
  	    ) {
  	stringPtr->numChars = numChars + appendNumChars;
      }
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * AppendUnicodeToUnicodeRep --
   *
   *	This function appends the contents of "unicode" to the Unicode rep of
   *	"objPtr". objPtr must already have a valid Unicode rep.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	objPtr's internal rep is reallocated.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  AppendUnicodeToUnicodeRep(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const Tcl_UniChar *unicode,	/* String to append. */
      int appendNumChars)		/* Number of chars of "unicode" to append. */
  {
      String *stringPtr;
      int numChars;
  
      if (appendNumChars < 0) {
  	appendNumChars = UnicodeLength(unicode);
      }
      if (appendNumChars == 0) {
  	return;
      }
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      /*
       * If not enough space has been allocated for the unicode rep, 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;
      stringCheckLimits(numChars);
  
      if (numChars > stringPtr->maxChars) {
  	int offset = -1;
  
  	/*
  	 * Protect against case where unicode points into the existing
  	 * stringPtr->unicode array. Force it to follow any relocations due to
  	 * the reallocs below.
  	 */
  
  	if (unicode && unicode >= stringPtr->unicode
  		&& unicode <= stringPtr->unicode + stringPtr->maxChars) {
  	    offset = unicode - stringPtr->unicode;
  	}
  
  	GrowUnicodeBuffer(objPtr, numChars);
  	stringPtr = GET_STRING(objPtr);
  
  	/*
  	 * Relocate unicode if needed; see above.
  	 */
  
  	if (offset >= 0) {
  	    unicode = stringPtr->unicode + offset;
  	}
      }
  
      /*
       * Copy the new string onto the end of the old string, then add the
       * trailing null.
       */
  
      if (unicode) {
  	memmove(stringPtr->unicode + stringPtr->numChars, unicode,
  		appendNumChars * sizeof(Tcl_UniChar));
      }
      stringPtr->unicode[numChars] = 0;
      stringPtr->numChars = numChars;
      stringPtr->allocated = 0;
  
      TclInvalidateStringRep(objPtr);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * AppendUnicodeToUtfRep --
   *
   *	This function converts the contents of "unicode" to UTF and appends
   *	the UTF to the string rep of "objPtr".
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	objPtr's internal rep is reallocated.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  AppendUnicodeToUtfRep(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const Tcl_UniChar *unicode,	/* String to convert to UTF. */
      int numChars)		/* Number of chars of "unicode" to convert. */
  {
      String *stringPtr = GET_STRING(objPtr);
  
      numChars = ExtendStringRepWithUnicode(objPtr, unicode, numChars);
  
      if (stringPtr->numChars != -1) {
  	stringPtr->numChars += numChars;
      }
  
  #if COMPAT
      /*
       * Invalidate the unicode rep.
       */
  
      stringPtr->hasUnicode = 0;
  #endif
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * AppendUtfToUnicodeRep --
   *
   *	This function converts the contents of "bytes" to Unicode and appends
   *	the Unicode to the Unicode rep of "objPtr". objPtr must already have a
   *	valid Unicode rep. numBytes must be non-negative.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	objPtr's internal rep is reallocated.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  AppendUtfToUnicodeRep(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const char *bytes,		/* String to convert to Unicode. */
      int numBytes)		/* Number of bytes of "bytes" to convert. */
  {
      String *stringPtr;
  
      if (numBytes == 0) {
  	return;
      }
  
      ExtendUnicodeRepWithString(objPtr, bytes, numBytes, -1);
      TclInvalidateStringRep(objPtr);
      stringPtr = GET_STRING(objPtr);
      stringPtr->allocated = 0;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * AppendUtfToUtfRep --
   *
   *	This function appends "numBytes" bytes of "bytes" to the UTF string
   *	rep of "objPtr". objPtr must already have a valid String rep.
   *	numBytes must be non-negative.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	objPtr's internal rep is reallocated.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  AppendUtfToUtfRep(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      const char *bytes,		/* String to append. */
      int numBytes)		/* Number of bytes of "bytes" to append. */
  {
      String *stringPtr;
      int newLength, oldLength;
  
      if (numBytes == 0) {
  	return;
      }
  
      /*
       * Copy the new string onto the end of the old string, then add the
       * trailing null.
       */
  
      if (objPtr->bytes == NULL) {
  	objPtr->length = 0;
      }
      oldLength = objPtr->length;
      newLength = numBytes + oldLength;
      if (newLength < 0) {
  	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
      }
  
      stringPtr = GET_STRING(objPtr);
      if (newLength > stringPtr->allocated) {
  	int offset = -1;
  
  	/*
  	 * Protect against case where unicode points into the existing
  	 * stringPtr->unicode array. Force it to follow any relocations due to
  	 * the reallocs below.
  	 */
  
  	if (bytes && bytes >= objPtr->bytes
  		&& bytes <= objPtr->bytes + objPtr->length) {
  	    offset = bytes - objPtr->bytes;
  	}
  
  	/*
  	 * TODO: consider passing flag=1: no overalloc on first append. This
  	 * would make test stringObj-8.1 fail.
  	 */
  
  	GrowStringBuffer(objPtr, newLength, 0);
  
  	/*
  	 * Relocate bytes if needed; see above.
  	 */
  
  	if (offset >= 0) {
  	    bytes = objPtr->bytes + offset;
  	}
      }
  
      /*
       * Invalidate the unicode data.
       */
  
      stringPtr->numChars = -1;
      stringPtr->hasUnicode = 0;
  
      if (bytes) {
  	memmove(objPtr->bytes + oldLength, bytes, numBytes);
      }
      objPtr->bytes[newLength] = 0;
      objPtr->length = newLength;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendStringsToObjVA --
   *
   *	This function 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_AppendStringsToObjVA(
      Tcl_Obj *objPtr,		/* Points to the object to append to. */
      va_list argList)		/* Variable argument list. */
  {
      if (Tcl_IsShared(objPtr)) {
  	Tcl_Panic("%s called with shared object", "Tcl_AppendStringsToObj");
      }
  
      while (1) {
  	const char *bytes = va_arg(argList, char *);
  
  	if (bytes == NULL) {
  	    break;
  	}
  	Tcl_AppendToObj(objPtr, bytes, -1);
      }
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendStringsToObj --
   *
   *	This function 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_Obj *objPtr,
      ...)
  {
      va_list argList;
  
      va_start(argList, objPtr);
      Tcl_AppendStringsToObjVA(objPtr, argList);
      va_end(argList);
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * Tcl_AppendFormatToObj --
   *
   *	This function appends a list of Tcl_Obj's to a Tcl_Obj according to
   *	the formatting instructions embedded in the format string. The
   *	formatting instructions are inspired by sprintf(). Returns TCL_OK when
   *	successful. If there's an error in the arguments, TCL_ERROR is
   *	returned, and an error message is written to the interp, if non-NULL.
   *
   * Results:
   *	A standard Tcl result.
   *
   * Side effects:
   *	None.
   *
   *----------------------------------------------------------------------
   */
  
  int
  Tcl_AppendFormatToObj(
      Tcl_Interp *interp,
      Tcl_Obj *appendObj,
      const char *format,
      int objc,
      Tcl_Obj *const objv[])
  {
      const char *span = format, *msg, *errCode;
      int numBytes = 0, objIndex = 0, gotXpg = 0, gotSequential = 0;
      int originalLength, limit;
      Tcl_UniChar ch = 0;
      static const char *mixedXPG =
  	    "cannot mix \"%\" and \"%n$\" conversion specifiers";
      static const char *const badIndex[2] = {
  	"not enough arguments for all format specifiers",
  	"\"%n$\" argument index out of range"
      };
      static const char *overflow = "max size for a Tcl value exceeded";
  
      if (Tcl_IsShared(appendObj)) {
  	Tcl_Panic("%s called with shared object", "Tcl_AppendFormatToObj");
      }
      TclGetStringFromObj(appendObj, &originalLength);
      limit = INT_MAX - originalLength;
  
      /*
       * Format string is NUL-terminated.
       */
  
      while (*format != '\0') {
  	char *end;
  	int gotMinus = 0, gotHash = 0, gotZero = 0, gotSpace = 0, gotPlus = 0;
  	int width, gotPrecision, precision, sawFlag, useShort = 0, useBig = 0;
  #ifndef TCL_WIDE_INT_IS_LONG
  	int useWide = 0;
  #endif
  	int newXpg, numChars, allocSegment = 0, segmentLimit, segmentNumBytes;
  	Tcl_Obj *segment;
  	int step = TclUtfToUniChar(format, &ch);
  
  	format += step;
  	if (ch != '%') {
  	    numBytes += step;
  	    continue;
  	}
  	if (numBytes) {
  	    if (numBytes > limit) {
  		msg = overflow;
  		errCode = "OVERFLOW";
  		goto errorMsg;
  	    }
  	    Tcl_AppendToObj(appendObj, span, numBytes);
  	    limit -= numBytes;
  	    numBytes = 0;
  	}
  
  	/*
  	 * Saw a % : process the format specifier.
  	 *
  	 * Step 0. Handle special case of escaped format marker (i.e., %%).
  	 */
  
  	step = TclUtfToUniChar(format, &ch);
  	if (ch == '%') {
  	    span = format;
  	    numBytes = step;
  	    format += step;
  	    continue;
  	}
  
  	/*
  	 * Step 1. XPG3 position specifier
  	 */
  
  	newXpg = 0;
  	if (isdigit(UCHAR(ch))) {
  	    int position = strtoul(format, &end, 10);
  
  	    if (*end == '$') {
  		newXpg = 1;
  		objIndex = position - 1;
  		format = end + 1;
  		step = TclUtfToUniChar(format, &ch);
  	    }
  	}
  	if (newXpg) {
  	    if (gotSequential) {
  		msg = mixedXPG;
  		errCode = "MIXEDSPECTYPES";
  		goto errorMsg;
  	    }
  	    gotXpg = 1;
  	} else {
  	    if (gotXpg) {
  		msg = mixedXPG;
  		errCode = "MIXEDSPECTYPES";
  		goto errorMsg;
  	    }
  	    gotSequential = 1;
  	}
  	if ((objIndex < 0) || (objIndex >= objc)) {
  	    msg = badIndex[gotXpg];
  	    errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
  	    goto errorMsg;
  	}
  
  	/*
  	 * Step 2. Set of flags.
  	 */
  
  	sawFlag = 1;
  	do {
  	    switch (ch) {
  	    case '-':
  		gotMinus = 1;
  		break;
  	    case '#':
  		gotHash = 1;
  		break;
  	    case '0':
  		gotZero = 1;
  		break;
  	    case ' ':
  		gotSpace = 1;
  		break;
  	    case '+':
  		gotPlus = 1;
  		break;
  	    default:
  		sawFlag = 0;
  	    }
  	    if (sawFlag) {
  		format += step;
  		step = TclUtfToUniChar(format, &ch);
  	    }
  	} while (sawFlag);
  
  	/*
  	 * Step 3. Minimum field width.
  	 */
  
  	width = 0;
  	if (isdigit(UCHAR(ch))) {
  	    width = strtoul(format, &end, 10);
  	    format = end;
  	    step = TclUtfToUniChar(format, &ch);
  	} else if (ch == '*') {
  	    if (objIndex >= objc - 1) {
  		msg = badIndex[gotXpg];
  		errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
  		goto errorMsg;
  	    }
  	    if (TclGetIntFromObj(interp, objv[objIndex], &width) != TCL_OK) {
  		goto error;
  	    }
  	    if (width < 0) {
  		width = -width;
  		gotMinus = 1;
  	    }
  	    objIndex++;
  	    format += step;
  	    step = TclUtfToUniChar(format, &ch);
  	}
  	if (width > limit) {
  	    msg = overflow;
  	    errCode = "OVERFLOW";
  	    goto errorMsg;
  	}
  
  	/*
  	 * Step 4. Precision.
  	 */
  
  	gotPrecision = precision = 0;
  	if (ch == '.') {
  	    gotPrecision = 1;
  	    format += step;
  	    step = TclUtfToUniChar(format, &ch);
  	}
  	if (isdigit(UCHAR(ch))) {
  	    precision = strtoul(format, &end, 10);
  	    format = end;
  	    step = TclUtfToUniChar(format, &ch);
  	} else if (ch == '*') {
  	    if (objIndex >= objc - 1) {
  		msg = badIndex[gotXpg];
  		errCode = gotXpg ? "INDEXRANGE" : "FIELDVARMISMATCH";
  		goto errorMsg;
  	    }
  	    if (TclGetIntFromObj(interp, objv[objIndex], &precision)
  		    != TCL_OK) {
  		goto error;
  	    }
  
  	    /*
  	     * TODO: Check this truncation logic.
  	     */
  
  	    if (precision < 0) {
  		precision = 0;
  	    }
  	    objIndex++;
  	    format += step;
  	    step = TclUtfToUniChar(format, &ch);
  	}
  
  	/*
  	 * Step 5. Length modifier.
  	 */
  
  	if (ch == 'h') {
  	    useShort = 1;
  	    format += step;
  	    step = TclUtfToUniChar(format, &ch);
  	} else if (ch == 'l') {
  	    format += step;
  	    step = TclUtfToUniChar(format, &ch);
  	    if (ch == 'l') {
  		useBig = 1;
  		format += step;
  		step = TclUtfToUniChar(format, &ch);
  #ifndef TCL_WIDE_INT_IS_LONG
  	    } else {
  		useWide = 1;
  #endif
  	    }
  	}
  
  	format += step;
  	span = format;
  
  	/*
  	 * Step 6. The actual conversion character.
  	 */
  
  	segment = objv[objIndex];
  	numChars = -1;
  	if (ch == 'i') {
  	    ch = 'd';
  	}
  	switch (ch) {
  	case '\0':
  	    msg = "format string ended in middle of field specifier";
  	    errCode = "INCOMPLETE";
  	    goto errorMsg;
  	case 's':
  	    if (gotPrecision) {
  		numChars = Tcl_GetCharLength(segment);
  		if (precision < numChars) {
  		    segment = Tcl_GetRange(segment, 0, precision - 1);
  		    numChars = precision;
  		    Tcl_IncrRefCount(segment);
  		    allocSegment = 1;
  		}
  	    }
  	    break;
  	case 'c': {
  	    char buf[TCL_UTF_MAX];
  	    int code, length;
  
  	    if (TclGetIntFromObj(interp, segment, &code) != TCL_OK) {
  		goto error;
  	    }
  	    length = Tcl_UniCharToUtf(code, buf);
  	    segment = Tcl_NewStringObj(buf, length);
  	    Tcl_IncrRefCount(segment);
  	    allocSegment = 1;
  	    break;
  	}
  
  	case 'u':
  	    if (useBig) {
  		msg = "unsigned bignum format is invalid";
  		errCode = "BADUNSIGNED";
  		goto errorMsg;
  	    }
  	case 'd':
  	case 'o':
  	case 'x':
  	case 'X':
  	case 'b': {
  	    short s = 0;	/* Silence compiler warning; only defined and
  				 * used when useShort is true. */
  	    long l;
  	    Tcl_WideInt w;
  	    mp_int big;
  	    int toAppend, isNegative = 0;
  
  	    if (useBig) {
  		if (Tcl_GetBignumFromObj(interp, segment, &big) != TCL_OK) {
  		    goto error;
  		}
  		isNegative = (mp_cmp_d(&big, 0) == MP_LT);
  #ifndef TCL_WIDE_INT_IS_LONG
  	    } else if (useWide) {
  		if (Tcl_GetWideIntFromObj(NULL, segment, &w) != TCL_OK) {
  		    Tcl_Obj *objPtr;
  
  		    if (Tcl_GetBignumFromObj(interp,segment,&big) != TCL_OK) {
  			goto error;
  		    }
  		    mp_mod_2d(&big, (int) CHAR_BIT*sizeof(Tcl_WideInt), &big);
  		    objPtr = Tcl_NewBignumObj(&big);
  		    Tcl_IncrRefCount(objPtr);
  		    Tcl_GetWideIntFromObj(NULL, objPtr, &w);
  		    Tcl_DecrRefCount(objPtr);
  		}
  		isNegative = (w < (Tcl_WideInt) 0);
  #endif
  	    } else if (TclGetLongFromObj(NULL, segment, &l) != TCL_OK) {
  		if (Tcl_GetWideIntFromObj(NULL, segment, &w) != TCL_OK) {
  		    Tcl_Obj *objPtr;
  
  		    if (Tcl_GetBignumFromObj(interp,segment,&big) != TCL_OK) {
  			goto error;
  		    }
  		    mp_mod_2d(&big, (int) CHAR_BIT * sizeof(long), &big);
  		    objPtr = Tcl_NewBignumObj(&big);
  		    Tcl_IncrRefCount(objPtr);
  		    TclGetLongFromObj(NULL, objPtr, &l);
  		    Tcl_DecrRefCount(objPtr);
  		} else {
  		    l = Tcl_WideAsLong(w);
  		}
  		if (useShort) {
  		    s = (short) l;
  		    isNegative = (s < (short) 0);
  		} else {
  		    isNegative = (l < (long) 0);
  		}
  	    } else if (useShort) {
  		s = (short) l;
  		isNegative = (s < (short) 0);
  	    } else {
  		isNegative = (l < (long) 0);
  	    }
  
  	    segment = Tcl_NewObj();
  	    allocSegment = 1;
  	    segmentLimit = INT_MAX;
  	    Tcl_IncrRefCount(segment);
  
  	    if ((isNegative || gotPlus || gotSpace) && (useBig || ch=='d')) {
  		Tcl_AppendToObj(segment,
  			(isNegative ? "-" : gotPlus ? "+" : " "), 1);
  		segmentLimit -= 1;
  	    }
  
  	    if (gotHash) {
  		switch (ch) {
  		case 'o':
  		    Tcl_AppendToObj(segment, "0", 1);
  		    segmentLimit -= 1;
  		    precision--;
  		    break;
  		case 'X':
  		    Tcl_AppendToObj(segment, "0X", 2);
  		    segmentLimit -= 2;
  		    break;
  		case 'x':
  		    Tcl_AppendToObj(segment, "0x", 2);
  		    segmentLimit -= 2;
  		    break;
  		case 'b':
  		    Tcl_AppendToObj(segment, "0b", 2);
  		    segmentLimit -= 2;
  		    break;
  		}
  	    }
  
  	    switch (ch) {
  	    case 'd': {
  		int length;
  		Tcl_Obj *pure;
  		const char *bytes;
  
  		if (useShort) {
  		    pure = Tcl_NewIntObj((int) s);
  #ifndef TCL_WIDE_INT_IS_LONG
  		} else if (useWide) {
  		    pure = Tcl_NewWideIntObj(w);
  #endif
  		} else if (useBig) {
  		    pure = Tcl_NewBignumObj(&big);
  		} else {
  		    pure = Tcl_NewLongObj(l);
  		}
  		Tcl_IncrRefCount(pure);
  		bytes = TclGetStringFromObj(pure, &length);
  
  		/*
  		 * Already did the sign above.
  		 */
  
  		if (*bytes == '-') {
  		    length--;
  		    bytes++;
  		}
  		toAppend = length;
  
  		/*
  		 * Canonical decimal string reps for integers are composed
  		 * entirely of one-byte encoded characters, so "length" is the
  		 * number of chars.
  		 */
  
  		if (gotPrecision) {
  		    if (length < precision) {
  			segmentLimit -= precision - length;
  		    }
  		    while (length < precision) {
  			Tcl_AppendToObj(segment, "0", 1);
  			length++;
  		    }
  		    gotZero = 0;
  		}
  		if (gotZero) {
  		    length += Tcl_GetCharLength(segment);
  		    if (length < width) {
  			segmentLimit -= width - length;
  		    }
  		    while (length < width) {
  			Tcl_AppendToObj(segment, "0", 1);
  			length++;
  		    }
  		}
  		if (toAppend > segmentLimit) {
  		    msg = overflow;
  		    errCode = "OVERFLOW";
  		    goto errorMsg;
  		}
  		Tcl_AppendToObj(segment, bytes, toAppend);
  		Tcl_DecrRefCount(pure);
  		break;
  	    }
  
  	    case 'u':
  	    case 'o':
  	    case 'x':
  	    case 'X':
  	    case 'b': {
  		Tcl_WideUInt bits = (Tcl_WideUInt) 0;
  		Tcl_WideInt numDigits = (Tcl_WideInt) 0;
  		int length, numBits = 4, base = 16, index = 0, shift = 0;
  		Tcl_Obj *pure;
  		char *bytes;
  
  		if (ch == 'u') {
  		    base = 10;
  		} else if (ch == 'o') {
  		    base = 8;
  		    numBits = 3;
  		} else if (ch == 'b') {
  		    base = 2;
  		    numBits = 1;
  		}
  		if (useShort) {
  		    unsigned short us = (unsigned short) s;
  
  		    bits = (Tcl_WideUInt) us;
  		    while (us) {
  			numDigits++;
  			us /= base;
  		    }
  #ifndef TCL_WIDE_INT_IS_LONG
  		} else if (useWide) {
  		    Tcl_WideUInt uw = (Tcl_WideUInt) w;
  
  		    bits = uw;
  		    while (uw) {
  			numDigits++;
  			uw /= base;
  		    }
  #endif
  		} else if (useBig && big.used) {
  		    int leftover = (big.used * DIGIT_BIT) % numBits;
  		    mp_digit mask = (~(mp_digit)0) << (DIGIT_BIT-leftover);
  
  		    numDigits = 1 +
  			    (((Tcl_WideInt) big.used * DIGIT_BIT) / numBits);
  		    while ((mask & big.dp[big.used-1]) == 0) {
  			numDigits--;
  			mask >>= numBits;
  		    }
  		    if (numDigits > INT_MAX) {
  			msg = overflow;
  			errCode = "OVERFLOW";
  			goto errorMsg;
  		    }
  		} else if (!useBig) {
  		    unsigned long ul = (unsigned long) l;
  
  		    bits = (Tcl_WideUInt) ul;
  		    while (ul) {
  			numDigits++;
  			ul /= base;
  		    }
  		}
  
  		/*
  		 * Need to be sure zero becomes "0", not "".
  		 */
  
  		if ((numDigits == 0) && !((ch == 'o') && gotHash)) {
  		    numDigits = 1;
  		}
  		pure = Tcl_NewObj();
  		Tcl_SetObjLength(pure, (int) numDigits);
  		bytes = TclGetString(pure);
  		toAppend = length = (int) numDigits;
  		while (numDigits--) {
  		    int digitOffset;
  
  		    if (useBig && big.used) {
  			if (index < big.used && (size_t) shift <
  				CHAR_BIT*sizeof(Tcl_WideUInt) - DIGIT_BIT) {
  			    bits |= ((Tcl_WideUInt) big.dp[index++]) << shift;
  			    shift += DIGIT_BIT;
  			}
  			shift -= numBits;
  		    }
  		    digitOffset = (int) (bits % base);
  		    if (digitOffset > 9) {
  			if (ch == 'X') {
  			    bytes[numDigits] = 'A' + digitOffset - 10;
  			} else {
  			    bytes[numDigits] = 'a' + digitOffset - 10;
  			}
  		    } else {
  			bytes[numDigits] = '0' + digitOffset;
  		    }
  		    bits /= base;
  		}
  		if (useBig) {
  		    mp_clear(&big);
  		}
  		if (gotPrecision) {
  		    if (length < precision) {
  			segmentLimit -= precision - length;
  		    }
  		    while (length < precision) {
  			Tcl_AppendToObj(segment, "0", 1);
  			length++;
  		    }
  		    gotZero = 0;
  		}
  		if (gotZero) {
  		    length += Tcl_GetCharLength(segment);
  		    if (length < width) {
  			segmentLimit -= width - length;
  		    }
  		    while (length < width) {
  			Tcl_AppendToObj(segment, "0", 1);
  			length++;
  		    }
  		}
  		if (toAppend > segmentLimit) {
  		    msg = overflow;
  		    errCode = "OVERFLOW";
  		    goto errorMsg;
  		}
  		Tcl_AppendObjToObj(segment, pure);
  		Tcl_DecrRefCount(pure);
  		break;
  	    }
  
  	    }
  	    break;
  	}
  
  	case 'e':
  	case 'E':
  	case 'f':
  	case 'g':
  	case 'G': {
  #define MAX_FLOAT_SIZE 320
  	    char spec[2*TCL_INTEGER_SPACE + 9], *p = spec;
  	    double d;
  	    int length = MAX_FLOAT_SIZE;
  	    char *bytes;
  
  	    if (Tcl_GetDoubleFromObj(interp, segment, &d) != TCL_OK) {
  		/* TODO: Figure out ACCEPT_NAN here */
  		goto error;
  	    }
  	    *p++ = '%';
  	    if (gotMinus) {
  		*p++ = '-';
  	    }
  	    if (gotHash) {
  		*p++ = '#';
  	    }
  	    if (gotZero) {
  		*p++ = '0';
  	    }
  	    if (gotSpace) {
  		*p++ = ' ';
  	    }
  	    if (gotPlus) {
  		*p++ = '+';
  	    }
  	    if (width) {
  		p += sprintf(p, "%d", width);
  		if (width > length) {
  		    length = width;
  		}
  	    }
  	    if (gotPrecision) {
  		*p++ = '.';
  		p += sprintf(p, "%d", precision);
  		if (precision > INT_MAX - length) {
  		    msg = overflow;
  		    errCode = "OVERFLOW";
  		    goto errorMsg;
  		}
  		length += precision;
  	    }
  
  	    /*
  	     * Don't pass length modifiers!
  	     */
  
  	    *p++ = (char) ch;
  	    *p = '\0';
  
  	    segment = Tcl_NewObj();
  	    allocSegment = 1;
  	    if (!Tcl_AttemptSetObjLength(segment, length)) {
  		msg = overflow;
  		errCode = "OVERFLOW";
  		goto errorMsg;
  	    }
  	    bytes = TclGetString(segment);
  	    if (!Tcl_AttemptSetObjLength(segment, sprintf(bytes, spec, d))) {
  		msg = overflow;
  		errCode = "OVERFLOW";
  		goto errorMsg;
  	    }
  	    break;
  	}
  	default:
  	    if (interp != NULL) {
  		Tcl_SetObjResult(interp,
  			Tcl_ObjPrintf("bad field specifier \"%c\"", ch));
  		Tcl_SetErrorCode(interp, "TCL", "FORMAT", "BADTYPE", NULL);
  	    }
  	    goto error;
  	}
  
  	if (width>0 && numChars<0) {
  	    numChars = Tcl_GetCharLength(segment);
  	}
  	if (!gotMinus && width>0) {
  	    if (numChars < width) {
  		limit -= width - numChars;
  	    }
  	    while (numChars < width) {
  		Tcl_AppendToObj(appendObj, (gotZero ? "0" : " "), 1);
  		numChars++;
  	    }
  	}
  
  	TclGetStringFromObj(segment, &segmentNumBytes);
  	if (segmentNumBytes > limit) {
  	    if (allocSegment) {
  		Tcl_DecrRefCount(segment);
  	    }
  	    msg = overflow;
  	    errCode = "OVERFLOW";
  	    goto errorMsg;
  	}
  	Tcl_AppendObjToObj(appendObj, segment);
  	limit -= segmentNumBytes;
  	if (allocSegment) {
  	    Tcl_DecrRefCount(segment);
  	}
  	if (width > 0) {
  	    if (numChars < width) {
  		limit -= width-numChars;
  	    }
  	    while (numChars < width) {
  		Tcl_AppendToObj(appendObj, (gotZero ? "0" : " "), 1);
  		numChars++;
  	    }
  	}
  
  	objIndex += gotSequential;
      }
      if (numBytes) {
  	if (numBytes > limit) {
  	    msg = overflow;
  	    errCode = "OVERFLOW";
  	    goto errorMsg;
  	}
  	Tcl_AppendToObj(appendObj, span, numBytes);
  	limit -= numBytes;
  	numBytes = 0;
      }
  
      return TCL_OK;
  
    errorMsg:
      if (interp != NULL) {
  	Tcl_SetObjResult(interp, Tcl_NewStringObj(msg, -1));
  	Tcl_SetErrorCode(interp, "TCL", "FORMAT", errCode, NULL);
      }
    error:
      Tcl_SetObjLength(appendObj, originalLength);
      return TCL_ERROR;
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * Tcl_Format--
   *
   * Results:
   *	A refcount zero Tcl_Obj.
   *
   * Side effects:
   *	None.
   *
   *---------------------------------------------------------------------------
   */
  
  Tcl_Obj *
  Tcl_Format(
      Tcl_Interp *interp,
      const char *format,
      int objc,
      Tcl_Obj *const objv[])
  {
      int result;
      Tcl_Obj *objPtr = Tcl_NewObj();
  
      result = Tcl_AppendFormatToObj(interp, objPtr, format, objc, objv);
      if (result != TCL_OK) {
  	Tcl_DecrRefCount(objPtr);
  	return NULL;
      }
      return objPtr;
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * AppendPrintfToObjVA --
   *
   * Results:
   *
   * Side effects:
   *
   *---------------------------------------------------------------------------
   */
  
  static void
  AppendPrintfToObjVA(
      Tcl_Obj *objPtr,
      const char *format,
      va_list argList)
  {
      int code, objc;
      Tcl_Obj **objv, *list = Tcl_NewObj();
      const char *p;
  
      p = format;
      Tcl_IncrRefCount(list);
      while (*p != '\0') {
  	int size = 0, seekingConversion = 1, gotPrecision = 0;
  	int lastNum = -1;
  
  	if (*p++ != '%') {
  	    continue;
  	}
  	if (*p == '%') {
  	    p++;
  	    continue;
  	}
  	do {
  	    switch (*p) {
  	    case '\0':
  		seekingConversion = 0;
  		break;
  	    case 's': {
  		const char *q, *end, *bytes = va_arg(argList, char *);
  		seekingConversion = 0;
  
  		/*
  		 * The buffer to copy characters from starts at bytes and ends
  		 * at either the first NUL byte, or after lastNum bytes, when
  		 * caller has indicated a limit.
  		 */
  
  		end = bytes;
  		while ((!gotPrecision || lastNum--) && (*end != '\0')) {
  		    end++;
  		}
  
  		/*
  		 * Within that buffer, we trim both ends if needed so that we
  		 * copy only whole characters, and avoid copying any partial
  		 * multi-byte characters.
  		 */
  
  		q = Tcl_UtfPrev(end, bytes);
  		if (!Tcl_UtfCharComplete(q, (int)(end - q))) {
  		    end = q;
  		}
  
  		q = bytes + TCL_UTF_MAX;
  		while ((bytes < end) && (bytes < q)
  			&& ((*bytes & 0xC0) == 0x80)) {
  		    bytes++;
  		}
  
  		Tcl_ListObjAppendElement(NULL, list,
  			Tcl_NewStringObj(bytes , (int)(end - bytes)));
  
  		break;
  	    }
  	    case 'c':
  	    case 'i':
  	    case 'u':
  	    case 'd':
  	    case 'o':
  	    case 'x':
  	    case 'X':
  		seekingConversion = 0;
  		switch (size) {
  		case -1:
  		case 0:
  		    Tcl_ListObjAppendElement(NULL, list, Tcl_NewLongObj(
  			    (long) va_arg(argList, int)));
  		    break;
  		case 1:
  		    Tcl_ListObjAppendElement(NULL, list, Tcl_NewLongObj(
  			    va_arg(argList, long)));
  		    break;
  		}
  		break;
  	    case 'e':
  	    case 'E':
  	    case 'f':
  	    case 'g':
  	    case 'G':
  		Tcl_ListObjAppendElement(NULL, list, Tcl_NewDoubleObj(
  			va_arg(argList, double)));
  		seekingConversion = 0;
  		break;
  	    case '*':
  		lastNum = (int) va_arg(argList, int);
  		Tcl_ListObjAppendElement(NULL, list, Tcl_NewIntObj(lastNum));
  		p++;
  		break;
  	    case '0': case '1': case '2': case '3': case '4':
  	    case '5': case '6': case '7': case '8': case '9': {
  		char *end;
  
  		lastNum = (int) strtoul(p, &end, 10);
  		p = end;
  		break;
  	    }
  	    case '.':
  		gotPrecision = 1;
  		p++;
  		break;
  	    /* TODO: support for wide (and bignum?) arguments */
  	    case 'l':
  		size = 1;
  		p++;
  		break;
  	    case 'h':
  		size = -1;
  	    default:
  		p++;
  	    }
  	} while (seekingConversion);
      }
      TclListObjGetElements(NULL, list, &objc, &objv);
      code = Tcl_AppendFormatToObj(NULL, objPtr, format, objc, objv);
      if (code != TCL_OK) {
  	Tcl_AppendPrintfToObj(objPtr,
  		"Unable to format \"%s\" with supplied arguments: %s",
  		format, Tcl_GetString(list));
      }
      Tcl_DecrRefCount(list);
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * Tcl_AppendPrintfToObj --
   *
   * Results:
   *	A standard Tcl result.
   *
   * Side effects:
   *	None.
   *
   *---------------------------------------------------------------------------
   */
  
  void
  Tcl_AppendPrintfToObj(
      Tcl_Obj *objPtr,
      const char *format,
      ...)
  {
      va_list argList;
  
      va_start(argList, format);
      AppendPrintfToObjVA(objPtr, format, argList);
      va_end(argList);
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * Tcl_ObjPrintf --
   *
   * Results:
   *	A refcount zero Tcl_Obj.
   *
   * Side effects:
   *	None.
   *
   *---------------------------------------------------------------------------
   */
  
  Tcl_Obj *
  Tcl_ObjPrintf(
      const char *format,
      ...)
  {
      va_list argList;
      Tcl_Obj *objPtr = Tcl_NewObj();
  
      va_start(argList, format);
      AppendPrintfToObjVA(objPtr, format, argList);
      va_end(argList);
      return objPtr;
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * TclGetStringStorage --
   *
   *	Returns the string storage space of a Tcl_Obj.
   *
   * Results:
   *	The pointer value objPtr->bytes is returned and the number of bytes
   *	allocated there is written to *sizePtr (if known).
   *
   * Side effects:
   *	May set objPtr->bytes.
   *
   *---------------------------------------------------------------------------
   */
  
  char *
  TclGetStringStorage(
      Tcl_Obj *objPtr,
      unsigned int *sizePtr)
  {
      String *stringPtr;
  
      if (objPtr->typePtr != &tclStringType || objPtr->bytes == NULL) {
  	return TclGetStringFromObj(objPtr, (int *)sizePtr);
      }
  
      stringPtr = GET_STRING(objPtr);
      *sizePtr = stringPtr->allocated;
      return objPtr->bytes;
  }
  /*
   *---------------------------------------------------------------------------
   *
   * TclStringObjReverse --
   *
   *	Implements the [string reverse] operation.
   *
   * Results:
   *	An unshared Tcl value which is the [string reverse] of the argument
   *	supplied. When sharing rules permit, the returned value might be the
   *	argument with modifications done in place.
   *
   * Side effects:
   *	May allocate a new Tcl_Obj.
   *
   *---------------------------------------------------------------------------
   */
  
  static void
  ReverseBytes(
      unsigned char *to,		/* Copy bytes into here... */
      unsigned char *from,	/* ...from here... */
      int count)		/* Until this many are copied, */
  				/* reversing as you go. */
  {
      unsigned char *src = from + count;
      if (to == from) {
  	/* Reversing in place */
  	while (--src > to) {
  	    unsigned char c = *src;
  	    *src = *to;
  	    *to++ = c;
  	}
      }  else {
  	while (--src >= from) {
  	    *to++ = *src;
  	}
      }
  }
  
  Tcl_Obj *
  TclStringObjReverse(
      Tcl_Obj *objPtr)
  {
      String *stringPtr;
      Tcl_UniChar ch = 0;
  
      if (TclIsPureByteArray(objPtr)) {
  	int numBytes;
  	unsigned char *from = Tcl_GetByteArrayFromObj(objPtr, &numBytes);
  
  	if (Tcl_IsShared(objPtr)) {
  	    objPtr = Tcl_NewByteArrayObj(NULL, numBytes);
  	}
  	ReverseBytes(Tcl_GetByteArrayFromObj(objPtr, NULL), from, numBytes);
  	return objPtr;
      }
  
      SetStringFromAny(NULL, objPtr);
      stringPtr = GET_STRING(objPtr);
  
      if (stringPtr->hasUnicode) {
  	Tcl_UniChar *from = Tcl_GetUnicode(objPtr);
  	Tcl_UniChar *src = from + stringPtr->numChars;
  
  	if (Tcl_IsShared(objPtr)) {
  	    Tcl_UniChar *to;
  
  	    /*
  	     * Create a non-empty, pure unicode value, so we can coax
  	     * Tcl_SetObjLength into growing the unicode rep buffer.
  	     */
  
  	    objPtr = Tcl_NewUnicodeObj(&ch, 1);
  	    Tcl_SetObjLength(objPtr, stringPtr->numChars);
  	    to = Tcl_GetUnicode(objPtr);
  	    while (--src >= from) {
  		*to++ = *src;
  	    }
  	} else {
  	    /* Reversing in place */
  	    while (--src > from) {
  		ch = *src;
  		*src = *from;
  		*from++ = ch;
  	    }
  	}
      }
  
      if (objPtr->bytes) {
  	int numChars = stringPtr->numChars;
  	int numBytes = objPtr->length;
  	char *to, *from = objPtr->bytes;
  
  	if (Tcl_IsShared(objPtr)) {
  	    objPtr = Tcl_NewObj();
  	    Tcl_SetObjLength(objPtr, numBytes);
  	}
  	to = objPtr->bytes;
  
  	if (numChars < numBytes) {
  	    /*
  	     * Either numChars == -1 and we don't know how many chars are
  	     * represented by objPtr->bytes and we need Pass 1 just in case,
  	     * or numChars >= 0 and we know we have fewer chars than bytes,
  	     * so we know there's a multibyte character needing Pass 1.
  	     *
  	     * Pass 1. Reverse the bytes of each multi-byte character.
  	     */
  	    int charCount = 0;
  	    int bytesLeft = numBytes;
  
  	    while (bytesLeft) {
  		/*
  		 * NOTE: We know that the from buffer is NUL-terminated.
  		 * It's part of the contract for objPtr->bytes values.
  		 * Thus, we can skip calling Tcl_UtfCharComplete() here.
  		 */
  		int bytesInChar = TclUtfToUniChar(from, &ch);
  
  		ReverseBytes((unsigned char *)to, (unsigned char *)from,
  			bytesInChar);
  		to += bytesInChar;
  		from += bytesInChar;
  		bytesLeft -= bytesInChar;
  		charCount++;
  	    }
  
  	    from = to = objPtr->bytes;
  	    stringPtr->numChars = charCount;
  	}
  	/* Pass 2. Reverse all the bytes. */
  	ReverseBytes((unsigned char *)to, (unsigned char *)from, numBytes);
      }
  
      return objPtr;
  }
  
  /*
   *---------------------------------------------------------------------------
   *
   * FillUnicodeRep --
   *
   *	Populate the Unicode internal rep with the Unicode form of its string
   *	rep. The object must alread have a "String" internal rep.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	Reallocates the String internal rep.
   *
   *---------------------------------------------------------------------------
   */
  
  static void
  FillUnicodeRep(
      Tcl_Obj *objPtr)		/* The object in which to fill the unicode
  				 * rep. */
  {
      String *stringPtr = GET_STRING(objPtr);
  
      ExtendUnicodeRepWithString(objPtr, objPtr->bytes, objPtr->length,
  	    stringPtr->numChars);
  }
  
  static void
  ExtendUnicodeRepWithString(
      Tcl_Obj *objPtr,
      const char *bytes,
      int numBytes,
      int numAppendChars)
  {
      String *stringPtr = GET_STRING(objPtr);
      int needed, numOrigChars = 0;
      Tcl_UniChar *dst, unichar = 0;
  
      if (stringPtr->hasUnicode) {
  	numOrigChars = stringPtr->numChars;
      }
      if (numAppendChars == -1) {
  	TclNumUtfChars(numAppendChars, bytes, numBytes);
      }
      needed = numOrigChars + numAppendChars;
      stringCheckLimits(needed);
  
      if (needed > stringPtr->maxChars) {
  	GrowUnicodeBuffer(objPtr, needed);
  	stringPtr = GET_STRING(objPtr);
      }
  
      stringPtr->hasUnicode = 1;
      if (bytes) {
  	stringPtr->numChars = needed;
      } else {
  	numAppendChars = 0;
      }
      for (dst=stringPtr->unicode + numOrigChars; numAppendChars-- > 0; dst++) {
  	bytes += TclUtfToUniChar(bytes, &unichar);
  	*dst = unichar;
      }
      *dst = 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(
      Tcl_Obj *srcPtr,		/* Object with internal rep to copy. Must have
  				 * an internal rep of type "String". */
      Tcl_Obj *copyPtr)		/* Object with internal rep to set. Must not
  				 * currently have an internal rep.*/
  {
      String *srcStringPtr = GET_STRING(srcPtr);
      String *copyStringPtr = NULL;
  
  #if COMPAT==0
      if (srcStringPtr->numChars == -1) {
  	/*
  	 * The String struct in the source value holds zero useful data. Don't
  	 * bother copying it. Don't even bother allocating space in which to
  	 * copy it. Just let the copy be untyped.
  	 */
  
  	return;
      }
  
      if (srcStringPtr->hasUnicode) {
  	int copyMaxChars;
  
  	if (srcStringPtr->maxChars / 2 >= srcStringPtr->numChars) {
  	    copyMaxChars = 2 * srcStringPtr->numChars;
  	} else {
  	    copyMaxChars = srcStringPtr->maxChars;
  	}
  	copyStringPtr = stringAttemptAlloc(copyMaxChars);
  	if (copyStringPtr == NULL) {
  	    copyMaxChars = srcStringPtr->numChars;
  	    copyStringPtr = stringAlloc(copyMaxChars);
  	}
  	copyStringPtr->maxChars = copyMaxChars;
  	memcpy(copyStringPtr->unicode, srcStringPtr->unicode,
  		srcStringPtr->numChars * sizeof(Tcl_UniChar));
  	copyStringPtr->unicode[srcStringPtr->numChars] = 0;
      } else {
  	copyStringPtr = stringAlloc(0);
  	copyStringPtr->maxChars = 0;
  	copyStringPtr->unicode[0] = 0;
      }
      copyStringPtr->hasUnicode = srcStringPtr->hasUnicode;
      copyStringPtr->numChars = srcStringPtr->numChars;
  
      /*
       * 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.
       */
  
      copyStringPtr->allocated = copyPtr->bytes ? copyPtr->length : 0;
  #else /* COMPAT!=0 */
      /*
       * If the src obj is a string of 1-byte Utf chars, then copy the string
       * rep of the source object and create an "empty" Unicode internal rep for
       * the new object. Otherwise, copy Unicode internal rep, and invalidate
       * the string rep of the new object.
       */
  
      if (srcStringPtr->hasUnicode && srcStringPtr->numChars > 0) {
  	/*
  	 * Copy the full allocation for the Unicode buffer.
  	 */
  
  	copyStringPtr = stringAlloc(srcStringPtr->maxChars);
  	copyStringPtr->maxChars = srcStringPtr->maxChars;
  	memcpy(copyStringPtr->unicode, srcStringPtr->unicode,
  		srcStringPtr->numChars * sizeof(Tcl_UniChar));
  	copyStringPtr->unicode[srcStringPtr->numChars] = 0;
  	copyStringPtr->allocated = 0;
      } else {
  	copyStringPtr = stringAlloc(0);
  	copyStringPtr->unicode[0] = 0;
  	copyStringPtr->maxChars = 0;
  
  	/*
  	 * 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.
  	 */
  
  	copyStringPtr->allocated = copyPtr->length;
      }
      copyStringPtr->numChars = srcStringPtr->numChars;
      copyStringPtr->hasUnicode = srcStringPtr->hasUnicode;
  #endif /* COMPAT==0 */
  
      SET_STRING(copyPtr, copyStringPtr);
      copyPtr->typePtr = &tclStringType;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * SetStringFromAny --
   *
   *	Create an internal representation of type "String" for an object.
   *
   * Results:
   *	This operation always succeeds and returns TCL_OK.
   *
   * Side effects:
   *	Any old internal reputation for objPtr is freed and the internal
   *	representation is set to "String".
   *
   *----------------------------------------------------------------------
   */
  
  static int
  SetStringFromAny(
      Tcl_Interp *interp,		/* Used for error reporting if not NULL. */
      Tcl_Obj *objPtr)		/* The object to convert. */
  {
      if (objPtr->typePtr != &tclStringType) {
  	String *stringPtr = stringAlloc(0);
  
  	/*
  	 * Convert whatever we have into an untyped value. Just A String.
  	 */
  
  	(void) TclGetString(objPtr);
  	TclFreeIntRep(objPtr);
  
  	/*
  	 * Create a basic String intrep that just points to the UTF-8 string
  	 * already in place at objPtr->bytes.
  	 */
  
  	stringPtr->numChars = -1;
  	stringPtr->allocated = objPtr->length;
  	stringPtr->maxChars = 0;
  	stringPtr->hasUnicode = 0;
  	SET_STRING(objPtr, stringPtr);
  	objPtr->typePtr = &tclStringType;
      }
      return TCL_OK;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * UpdateStringOfString --
   *
   *	Update the string representation for an object whose internal
   *	representation is "String".
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	The object's string may be set by converting its Unicode represention
   *	to UTF format.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  UpdateStringOfString(
      Tcl_Obj *objPtr)		/* Object with string rep to update. */
  {
      String *stringPtr = GET_STRING(objPtr);
  
      /*
       * This routine is only called when we need to generate the
       * string rep objPtr->bytes because it does not exist -- it is NULL.
       * In that circumstance, any lingering claim about the size of
       * memory pointed to by that NULL pointer is clearly bogus, and
       * needs a reset.
       */
  
      stringPtr->allocated = 0;
  
      if (stringPtr->numChars == 0) {
  	TclInitStringRep(objPtr, tclEmptyStringRep, 0);
      } else {
  	(void) ExtendStringRepWithUnicode(objPtr, stringPtr->unicode,
  		stringPtr->numChars);
      }
  }
  
  static int
  ExtendStringRepWithUnicode(
      Tcl_Obj *objPtr,
      const Tcl_UniChar *unicode,
      int numChars)
  {
      /*
       * Pre-condition: this is the "string" Tcl_ObjType.
       */
  
      int i, origLength, size = 0;
      char *dst, buf[TCL_UTF_MAX];
      String *stringPtr = GET_STRING(objPtr);
  
      if (numChars < 0) {
  	numChars = UnicodeLength(unicode);
      }
  
      if (numChars == 0) {
  	return 0;
      }
  
      if (objPtr->bytes == NULL) {
  	objPtr->length = 0;
      }
      size = origLength = objPtr->length;
  
      /*
       * Quick cheap check in case we have more than enough room.
       */
  
      if (numChars <= (INT_MAX - size)/TCL_UTF_MAX
  	    && stringPtr->allocated >= size + numChars * TCL_UTF_MAX) {
  	goto copyBytes;
      }
  
      for (i = 0; i < numChars && size >= 0; i++) {
  	size += Tcl_UniCharToUtf((int) unicode[i], buf);
      }
      if (size < 0) {
  	Tcl_Panic("max size for a Tcl value (%d bytes) exceeded", INT_MAX);
      }
  
      /*
       * Grow space if needed.
       */
  
      if (size > stringPtr->allocated) {
  	GrowStringBuffer(objPtr, size, 1);
      }
  
    copyBytes:
      dst = objPtr->bytes + origLength;
      for (i = 0; i < numChars; i++) {
  	dst += Tcl_UniCharToUtf((int) unicode[i], dst);
      }
      *dst = '\0';
      objPtr->length = dst - objPtr->bytes;
      return numChars;
  }
  
  /*
   *----------------------------------------------------------------------
   *
   * FreeStringInternalRep --
   *
   *	Deallocate the storage associated with a String data object's internal
   *	representation.
   *
   * Results:
   *	None.
   *
   * Side effects:
   *	Frees memory.
   *
   *----------------------------------------------------------------------
   */
  
  static void
  FreeStringInternalRep(
      Tcl_Obj *objPtr)		/* Object with internal rep to free. */
  {
      ckfree(GET_STRING(objPtr));
      objPtr->typePtr = NULL;
  }
  
  /*
   * Local Variables:
   * mode: c
   * c-basic-offset: 4
   * fill-column: 78
   * End:
   */
  