libs-base/Source/GSAttributedString.m

/**
   GSAttributedString.m

   Implementation of concrete subclass of a string class with attributes

   Copyright (C) 1997,1999 Free Software Foundation, Inc.

   Written by: ANOQ of the sun <anoq@vip.cybercity.dk>
   Date: November 1997
   Rewrite by: Richard Frith-Macdonald <richard@brainstorm.co.uk>
   Date: April 1999

   This file is part of GNUStep-base

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   If you are interested in a warranty or support for this source code,
   contact Scott Christley <scottc@net-community.com> for more information.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02111 USA.
*/

/* Warning -	[-initWithString:attributes:] is the designated initialiser,
 *		but it doesn't provide any way to perform the function of the
 *		[-initWithAttributedString:] initialiser.
 *		In order to work round this, the string argument of the
 *		designated initialiser has been overloaded such that it
 *		is expected to accept an NSAttributedString here instead of
 *		a string.  If you create an NSAttributedString subclass, you
 *		must make sure that your implementation of the initialiser
 *		copes with either an NSString or an NSAttributedString.
 *		If it receives an NSAttributedString, it should ignore the
 *		attributes argument and use the values from the string.
 */

#import "common.h"
#import "GNUstepBase/GSLock.h"
#import "GNUstepBase/NSMutableString+GNUstepBase.h"
#import "Foundation/NSAttributedString.h"
#import "Foundation/NSException.h"
#import "Foundation/NSRange.h"
#import "Foundation/NSArray.h"
#import "Foundation/NSInvocation.h"
#import "Foundation/NSLock.h"
#import "Foundation/NSProxy.h"
#import "Foundation/NSThread.h"
#import "Foundation/NSNotification.h"

#define		SANITY_CHECKS	0


@interface GSAttributedString : NSAttributedString
{
  NSString		*_textChars;
  NSMutableArray	*_infoArray;
}

- (id) initWithString: (NSString*)aString
	   attributes: (NSDictionary*)attributes;
- (NSString*) string;
- (NSDictionary*) attributesAtIndex: (NSUInteger)index
		     effectiveRange: (NSRange*)aRange;

@end

@interface GSMutableAttributedString : NSMutableAttributedString
{
  NSMutableString	*_textChars;
  NSMutableArray	*_infoArray;
  NSString		*_textProxy;
}

- (id) initWithString: (NSString*)aString
	   attributes: (NSDictionary*)attributes;
- (NSString*) string;
- (NSDictionary*) attributesAtIndex: (NSUInteger)index
		     effectiveRange: (NSRange*)aRange;
- (void) setAttributes: (NSDictionary*) attributes
		 range: (NSRange)range;
- (void) replaceCharactersInRange: (NSRange)range
		       withString: (NSString*)aString;

@end



#define	GSI_MAP_RETAIN_KEY(M, X)	
#define	GSI_MAP_RELEASE_KEY(M, X)	
#define	GSI_MAP_RETAIN_VAL(M, X)	
#define	GSI_MAP_RELEASE_VAL(M, X)	
#define	GSI_MAP_EQUAL(M, X,Y)	[(X).obj isEqualToDictionary: (Y).obj]
#define GSI_MAP_KTYPES	GSUNION_OBJ
#define GSI_MAP_VTYPES	GSUNION_NSINT
#define	GSI_MAP_NOCLEAN	1

#if	GS_WITH_GC
#include	<gc/gc_typed.h>
static GC_descr	nodeDesc;	// Type descriptor for map node.
#define	GSI_MAP_NODES(M, X) \
(GSIMapNode)GC_calloc_explicitly_typed(X, sizeof(GSIMapNode_t), nodeDesc)
#endif

#include "GNUstepBase/GSIMap.h"

static NSLock		*attrLock = nil;
static GSIMapTable_t	attrMap;
static SEL		lockSel;
static SEL		unlockSel;
static IMP		lockImp;
static IMP		unlockImp;

#define	ALOCK()	if (attrLock != nil) (*lockImp)(attrLock, lockSel)
#define	AUNLOCK() if (attrLock != nil) (*unlockImp)(attrLock, unlockSel)

@class  GSCachedDictionary;
@protocol       GSCachedDictionary
- (void) _uncache;
@end

/* Add a dictionary to the cache - if it was not already there, return
 * the copy added to the cache, if it was, count it and return retained
 * object that was there.
 */
static NSDictionary*
cacheAttributes(NSDictionary *attrs)
{
  if (nil != attrs)
    {
      GSIMapNode	node;

      ALOCK();
      node = GSIMapNodeForKey(&attrMap, (GSIMapKey)((id)attrs));
      if (node == 0)
        {
          /* Deep copy of dictionary, including copying objects ....
           * result in an immutable dictionary that can safely be cached
           * unless the copied objects or their contents are mutated.
           */
          attrs = [(NSDictionary*)[GSCachedDictionary alloc]
            initWithDictionary: attrs copyItems: YES];
          GSIMapAddPair(&attrMap,
            (GSIMapKey)((id)attrs), (GSIMapVal)(NSUInteger)1);
        }
      else
        {
          node->value.nsu++;
          attrs = node->key.obj;
        }
      AUNLOCK();
    }
  return attrs;
}

/* Decrement the count of a dictionary in the cache and release it.
 * If the count goes to zero, remove it from the cache.
 */
static void
unCacheAttributes(NSDictionary *attrs)
{
  if (nil != attrs)
    {
      GSIMapBucket              bucket;
      BOOL                      found = NO;
      id<GSCachedDictionary>    removed = nil;

      ALOCK();
      bucket = GSIMapBucketForKey(&attrMap, (GSIMapKey)((id)attrs));
      if (bucket != 0)
        {
          GSIMapNode     node;

          node = GSIMapNodeForKeyInBucket(&attrMap,
            bucket, (GSIMapKey)((id)attrs));
          if (node != 0)
            {
              found = YES;
              if (--node->value.nsu == 0)
                {
                  removed = node->key.obj;
                  GSIMapRemoveNodeFromMap(&attrMap, bucket, node);
                  GSIMapFreeNode(&attrMap, node);
                }
            }
        }
      AUNLOCK();
      if (nil != removed)
        {
          [removed _uncache];
        }
      if (NO == found)
        {
          [NSException raise: NSInternalInconsistencyException
                      format: @"NSAttributedString attempt to remove attributes which are not found in the cache.  Did someone mutate an object in the attributes dictionary?  The object to remove was %@", attrs];
        }
    }
}



@interface	GSAttrInfo : NSObject
{
@public
  unsigned	loc;
  NSDictionary	*attrs;
}

+ (GSAttrInfo*) newWithZone: (NSZone*)z value: (NSDictionary*)a at: (unsigned)l;

@end

@implementation	GSAttrInfo

+ (void) initialize
{
  if (nil == attrLock)
    {
      attrLock = [NSLock new];
      lockSel = @selector(lock);
      unlockSel = @selector(unlock);
      lockImp = [attrLock methodForSelector: lockSel];
      unlockImp = [attrLock methodForSelector: unlockSel];
      GSIMapInitWithZoneAndCapacity(&attrMap, NSDefaultMallocZone(), 32);
    }
}

/*
 * Called to record attributes at a particular location - the given attributes
 * dictionary must have been produced by 'cacheAttributes()' so that it is
 * already copied/retained and this method doesn't need to do it.
 */
+ (GSAttrInfo*) newWithZone: (NSZone*)z value: (NSDictionary*)a at: (unsigned)l;
{
  GSAttrInfo	*info = (GSAttrInfo*)NSAllocateObject(self, 0, z);

  info->loc = l;
  info->attrs = cacheAttributes(a);
  return info;
}

- (void) dealloc
{
  [self finalize];
  [super dealloc];
}

- (NSString*) description
{
  return [NSString stringWithFormat: @"Attributes at %u are - %@",
    loc, attrs];
}

- (void) encodeWithCoder: (NSCoder*)aCoder
{
  [aCoder encodeValueOfObjCType: @encode(unsigned) at: &loc];
  [aCoder encodeValueOfObjCType: @encode(id) at: &attrs];
}

- (void) finalize
{
  unCacheAttributes(attrs);
  attrs = nil;
}

- (id) initWithCoder: (NSCoder*)aCoder
{
  NSDictionary  *a;

  [aCoder decodeValueOfObjCType: @encode(unsigned) at: &loc];
  a = [aCoder decodeObject];
  attrs = cacheAttributes(a);
  return self;
}

- (id) replacementObjectForPortCoder: (NSPortCoder*)aCoder
{
  return self;
}

@end



@implementation GSAttributedString

static	GSAttrInfo	*blank;

static Class	infCls = 0;

static SEL	infSel;
static SEL	addSel;
static SEL	cntSel;
static SEL	insSel;
static SEL	oatSel;
static SEL	remSel;

static IMP	infImp;
static void	(*addImp)(NSMutableArray*,SEL,id);
static unsigned (*cntImp)(NSArray*,SEL);
static void	(*insImp)(NSMutableArray*,SEL,id,unsigned);
static IMP	oatImp;
static void	(*remImp)(NSMutableArray*,SEL,unsigned);

#define	NEWINFO(Z,O,L)	((*infImp)(infCls, infSel, (Z), (O), (L)))
#define	ADDOBJECT(O)	((*addImp)(_infoArray, addSel, (O)))
#define	INSOBJECT(O,I)	((*insImp)(_infoArray, insSel, (O), (I)))
#define	OBJECTAT(I)	((*oatImp)(_infoArray, oatSel, (I)))
#define	REMOVEAT(I)	((*remImp)(_infoArray, remSel, (I)))

static void
_setAttributesFrom(
  NSAttributedString *attributedString,
  NSRange aRange,
  NSMutableArray *_infoArray)
{
  NSZone	*z = [_infoArray zone];
  NSRange	range;
  NSDictionary	*attr;
  GSAttrInfo	*info;
  unsigned	loc;

  /*
   * remove any old attributes of the string.
   */
  [_infoArray removeAllObjects];

  if (aRange.length == 0)
    {
      attr = blank->attrs;
      range = aRange; /* Set to satisfy the loop condition below. */
    }
  else
    {
      attr = [attributedString attributesAtIndex: aRange.location
				  effectiveRange: &range];
    }
  info = NEWINFO(z, attr, 0);
  ADDOBJECT(info);
  RELEASE(info);

  while ((loc = NSMaxRange(range)) < NSMaxRange(aRange))
    {
      attr = [attributedString attributesAtIndex: loc
				  effectiveRange: &range];
      info = NEWINFO(z, attr, loc - aRange.location);
      ADDOBJECT(info);
      RELEASE(info);
    }
}

inline static NSDictionary*
_attributesAtIndexEffectiveRange(
  unsigned int index,
  NSRange *aRange,
  unsigned int tmpLength,
  NSMutableArray *_infoArray,
  unsigned int *foundIndex)
{
  unsigned	low, high, used, cnt, nextLoc;
  GSAttrInfo	*found = nil;

  used = (*cntImp)(_infoArray, cntSel);
  NSCAssert(used > 0, NSInternalInconsistencyException);
  high = used - 1;

  if (index >= tmpLength)
    {
      if (index == tmpLength)
	{
	  found = OBJECTAT(high);
	  if (foundIndex != 0)
	    {
	      *foundIndex = high;
	    }
	  if (aRange != 0)
	    {
	      aRange->location = found->loc;
	      aRange->length = tmpLength - found->loc;
	    }
	  return found->attrs;
	}
      [NSException raise: NSRangeException
		  format: @"index is out of range in function "
			  @"_attributesAtIndexEffectiveRange()"];
    }

  /*
   * Binary search for efficiency in huge attributed strings
   */
  low = 0;
  while (low <= high)
    {
      cnt = (low + high) / 2;
      found = OBJECTAT(cnt);
      if (found->loc > index)
	{
	  high = cnt - 1;
	}
      else
	{
	  if (cnt >= used - 1)
	    {
	      nextLoc = tmpLength;
	    }
	  else
	    {
	      GSAttrInfo	*inf = OBJECTAT(cnt + 1);

	      nextLoc = inf->loc;
	    }
	  if (found->loc == index || index < nextLoc)
	    {
	      //Found
	      if (aRange != 0)
		{
		  aRange->location = found->loc;
		  aRange->length = nextLoc - found->loc;
		}
	      if (foundIndex != 0)
		{
		  *foundIndex = cnt;
		}
	      return found->attrs;
	    }
	  else
	    {
	      low = cnt + 1;
	    }
	}
    }
  NSCAssert(NO,@"Error in binary search algorithm");
  return nil;
}

+ (void) initialize
{
  if (infCls == 0)
    {
      NSMutableArray	*a;
      NSDictionary	*d;

#if	GS_WITH_GC
      /* We create a typed memory descriptor for map nodes.
       * Only the pointer to the key needs to be scanned.
       */
      GC_word	w[GC_BITMAP_SIZE(GSIMapNode_t)] = {0};
      GC_set_bit(w, GC_WORD_OFFSET(GSIMapNode_t, key));
      nodeDesc = GC_make_descriptor(w, GC_WORD_LEN(GSIMapNode_t));
#endif

      infSel = @selector(newWithZone:value:at:);
      addSel = @selector(addObject:);
      cntSel = @selector(count);
      insSel = @selector(insertObject:atIndex:);
      oatSel = @selector(objectAtIndex:);
      remSel = @selector(removeObjectAtIndex:);

      infCls = [GSAttrInfo class];
      infImp = [infCls methodForSelector: infSel];

      d = [NSDictionary new];
      blank = NEWINFO(NSDefaultMallocZone(), d, 0);
      [[NSObject leakAt: &blank] release];
      RELEASE(d);

      a = [NSMutableArray allocWithZone: NSDefaultMallocZone()];
      a = [a initWithCapacity: 1];
      addImp = (void (*)(NSMutableArray*,SEL,id))[a methodForSelector: addSel];
      cntImp = (unsigned (*)(NSArray*,SEL))[a methodForSelector: cntSel];
      insImp = (void (*)(NSMutableArray*,SEL,id,unsigned))
	[a methodForSelector: insSel];
      oatImp = [a methodForSelector: oatSel];
      remImp = (void (*)(NSMutableArray*,SEL,unsigned))
	[a methodForSelector: remSel];
      RELEASE(a);
    }
  [[NSObject leakAt: &attrLock] release];
}

- (id) initWithString: (NSString*)aString
	   attributes: (NSDictionary*)attributes
{
  NSZone	*z = [self zone];

  if (nil == aString)
    {
      [NSException raise: NSInvalidArgumentException
		  format: @"aString object passed to -[GSAttributedString initWithString:attributes:] is nil"];
    }
  if (![aString respondsToSelector: @selector(length)])
    {
      [NSException raise: NSInvalidArgumentException
		  format: @"aString object passed to -[GSAttributedString initWithString:attributes:] does not respond to -length"];
    }

  _infoArray = [[NSMutableArray allocWithZone: z] initWithCapacity: 1];
  if (aString != nil && [aString isKindOfClass: [NSAttributedString class]])
    {
      NSAttributedString	*as = (NSAttributedString*)aString;
      unsigned			len;

      aString = [as string];
      len = [aString length];
      _setAttributesFrom(as, NSMakeRange(0, len), _infoArray);
    }
  else
    {
      GSAttrInfo	*info;

      if (attributes == nil)
	{
	  attributes = blank->attrs;
	}
      info = NEWINFO(z, attributes, 0);
      ADDOBJECT(info);
      RELEASE(info);
    }
  if (aString == nil)
    _textChars = @"";
  else
    _textChars = [aString copyWithZone: z];
  return self;
}

- (NSString*) string
{
  return AUTORELEASE([_textChars copyWithZone: NSDefaultMallocZone()]);
}

- (NSDictionary*) attributesAtIndex: (NSUInteger)index
		     effectiveRange: (NSRange*)aRange
{
  return _attributesAtIndexEffectiveRange(
    index, aRange, [_textChars length], _infoArray, NULL);
}

- (void) dealloc
{
  RELEASE(_textChars);
  RELEASE(_infoArray);
  [super dealloc];
}


// The superclass implementation is correct but too slow
- (NSUInteger) length
{
  return [_textChars length];
}

@end


@implementation GSMutableAttributedString

#if	SANITY_CHECKS

#define	SANITY()	[self _sanity]

#else
#define	SANITY()	
#endif

/* We always compile in this method so that it is available from
 * regression test cases.  */
- (void) _sanity
{
  GSAttrInfo	*info;
  unsigned	i;
  unsigned	l = 0;
  unsigned	len = [_textChars length];
  unsigned	c = (*cntImp)(_infoArray, cntSel);

  NSAssert(c > 0, NSInternalInconsistencyException);
  info = OBJECTAT(0);
  NSAssert(info->loc == 0, NSInternalInconsistencyException);
  for (i = 1; i < c; i++)
    {
      info = OBJECTAT(i);
      NSAssert(info->loc > l, NSInternalInconsistencyException);
      NSAssert(info->loc < len, NSInternalInconsistencyException);
      l = info->loc;
    }
}

+ (void) initialize
{
  [GSAttributedString class];	// Ensure immutable class is initialised
}

- (id) initWithString: (NSString*)aString
	   attributes: (NSDictionary*)attributes
{
  NSZone	*z = [self zone];

  if (nil == aString)
    {
      [NSException raise: NSInvalidArgumentException
		  format: @"aString object passed to -[GSAttributedString initWithString:attributes:] is nil"];
    }
  if (![aString respondsToSelector: @selector(length)])
    {
      [NSException raise: NSInvalidArgumentException
		  format: @"aString object passed to -[GSAttributedString initWithString:attributes:] does not respond to -length"];
    }

  _infoArray = [[NSMutableArray allocWithZone: z] initWithCapacity: 1];
  if (aString != nil && [aString isKindOfClass: [NSAttributedString class]])
    {
      NSAttributedString	*as = (NSAttributedString*)aString;

      aString = [as string];
      _setAttributesFrom(as, NSMakeRange(0, [aString length]), _infoArray);
    }
  else
    {
      GSAttrInfo	*info;

      if (attributes == nil)
        {
          attributes = blank->attrs;
        }
      info = NEWINFO(z, attributes, 0);
      ADDOBJECT(info);
      RELEASE(info);
    }
/* WARNING ... NSLayoutManager depends on the fact that we create the
 * _textChars instance variable by copying the aString argument to get
 * its own string subclass into the attributed string.
 */
  if (aString == nil)
    _textChars = [[NSMutableString allocWithZone: z] init];
  else
    _textChars = [aString mutableCopyWithZone: z];
SANITY();
  return self;
}

- (NSString*) string
{
  /* NB. This method is SUPPOSED to return a proxy to the mutable string!
   * This is a performance feature documented ifor OSX.
   */
  if (_textProxy == nil)
    {
      _textProxy = [[_textChars immutableProxy] retain];
    }
  return _textProxy;
}

- (NSDictionary*) attributesAtIndex: (NSUInteger)index
		     effectiveRange: (NSRange*)aRange
{
  unsigned	dummy;
  return _attributesAtIndexEffectiveRange(
    index, aRange, [_textChars length], _infoArray, &dummy);
}

/*
 *	Primitive method! Sets attributes and values for a given range of
 *	characters, replacing any previous attributes and values for that
 *	range.
 *
 *	Sets the attributes for the characters in aRange to attributes.
 *	These new attributes replace any attributes previously associated
 *	with the characters in aRange. Raises an NSRangeException if any
 *	part of aRange lies beyond the end of the receiver's characters.
 *	See also: - addAtributes: range: , - removeAttributes: range:
 */
- (void) setAttributes: (NSDictionary*)attributes
		 range: (NSRange)range
{
  unsigned	tmpLength;
  unsigned	arrayIndex = 0;
  unsigned	arraySize;
  NSRange	effectiveRange = NSMakeRange(0, NSNotFound);
  unsigned	afterRangeLoc, beginRangeLoc;
  NSDictionary	*attrs;
  NSZone	*z = [self zone];
  GSAttrInfo	*info;

  if (range.length == 0)
    {
      NSWarnMLog(@"Attempt to set attribute for zero-length range");
      return;
    }
  if (attributes == nil)
    {
      attributes = blank->attrs;
    }
SANITY();
  tmpLength = [_textChars length];
  GS_RANGE_CHECK(range, tmpLength);
  arraySize = (*cntImp)(_infoArray, cntSel);
  beginRangeLoc = range.location;
  afterRangeLoc = NSMaxRange(range);
  if (afterRangeLoc < tmpLength)
    {
      /*
       * Locate the first range that extends beyond our range.
       */
      attrs = _attributesAtIndexEffectiveRange(
	afterRangeLoc, &effectiveRange, tmpLength, _infoArray, &arrayIndex);
      if (attrs == attributes)
        {
          /*
           * The located range has the same attributes as us - so we can
           * extend our range to include it.
           */
          if (effectiveRange.location < beginRangeLoc)
            {
              range.length += beginRangeLoc - effectiveRange.location;
              range.location = effectiveRange.location;
              beginRangeLoc = range.location;
            }
          if (NSMaxRange(effectiveRange) > afterRangeLoc)
            {
              range.length = NSMaxRange(effectiveRange) - range.location;
            }
        }
      else if (effectiveRange.location > beginRangeLoc)
	{
	  /*
	   * The located range also starts at or after our range.
	   */
	  info = OBJECTAT(arrayIndex);
	  info->loc = afterRangeLoc;
	  arrayIndex--;
	}
      else if (NSMaxRange(effectiveRange) > afterRangeLoc)
	{
	  /*
	   * The located range ends after our range.
	   * Create a subrange to go from our end to the end of the old range.
	   */
	  info = NEWINFO(z, attrs, afterRangeLoc);
	  arrayIndex++;
	  INSOBJECT(info, arrayIndex);
	  RELEASE(info);
	  arrayIndex--;
	}
    }
  else
    {
      arrayIndex = arraySize - 1;
    }

  /*
   * Remove any ranges completely within ours
   */
  while (arrayIndex > 0)
    {
      info = OBJECTAT(arrayIndex-1);
      if (info->loc < beginRangeLoc)
	break;
      REMOVEAT(arrayIndex);
      arrayIndex--;
    }

  /*
   * Use the location/attribute info in the current slot if possible,
   * otherwise, add a new slot and use that.
   */
  info = OBJECTAT(arrayIndex);
  if (info->loc >= beginRangeLoc)
    {
      info->loc = beginRangeLoc;
      if (info->attrs != attributes)
	{
	  unCacheAttributes(info->attrs);
	  info->attrs = cacheAttributes(attributes);
	}
    }
  else if (info->attrs != attributes)
    {
      arrayIndex++;
      info = NEWINFO(z, attributes, beginRangeLoc);
      INSOBJECT(info, arrayIndex);
      RELEASE(info);
    }

SANITY();
}

- (void) replaceCharactersInRange: (NSRange)range
		       withString: (NSString*)aString
{
  unsigned	tmpLength;
  unsigned	arrayIndex = 0;
  unsigned	arraySize;
  NSRange	effectiveRange = NSMakeRange(0, NSNotFound);
  GSAttrInfo	*info;
  int		moveLocations;
  unsigned	start;

SANITY();
  if (aString == nil)
    {
      aString = @"";
    }
  tmpLength = [_textChars length];
  GS_RANGE_CHECK(range, tmpLength);
  if (range.location == tmpLength)
    {
      /*
       * Special case - replacing a zero length string at the end
       * simply appends the new string and attributes are inherited.
       */
      [_textChars appendString: aString];
      goto finish;
    }

  arraySize = (*cntImp)(_infoArray, cntSel);
  if (arraySize == 1)
    {
      /*
       * Special case - if the string has only one set of attributes
       * then the replacement characters will get them too.
       */
      [_textChars replaceCharactersInRange: range withString: aString];
      goto finish;
    }

  /*
   * Get the attributes to associate with our replacement string.
   * Should be those of the first character replaced.
   * If the range replaced is empty, we use the attributes of the
   * previous character (if possible).
   */
  if (range.length == 0 && range.location > 0)
    start = range.location - 1;
  else
    start = range.location;
  _attributesAtIndexEffectiveRange(start, &effectiveRange,
    tmpLength, _infoArray, &arrayIndex);

  moveLocations = [aString length] - range.length;

  arrayIndex++;
  if (NSMaxRange(effectiveRange) < NSMaxRange(range))
    {
      /*
       * Remove all range info for ranges enclosed within the one
       * we are replacing.  Adjust the start point of a range that
       * extends beyond ours.
       */
      info = OBJECTAT(arrayIndex);
      if (info->loc < NSMaxRange(range))
	{
	  unsigned int	next = arrayIndex + 1;

	  while (next < arraySize)
	    {
	      GSAttrInfo	*n = OBJECTAT(next);
	      if (n->loc <= NSMaxRange(range))
		{
		  REMOVEAT(arrayIndex);
		  arraySize--;
		  info = n;
		}
	      else
		{
		  break;
		}
	    }
	}
      if (NSMaxRange(range) < [_textChars length])
	{
	  info->loc = NSMaxRange(range);
	}
      else
	{
	  REMOVEAT(arrayIndex);
	  arraySize--;
	}
    }

  /*
   * If we are replacing a range with a zero length string and the
   * range we are using matches the range replaced, then we must
   * remove it from the array to avoid getting a zero length range.
   */
  if ((moveLocations + range.length) == 0)
    {
      _attributesAtIndexEffectiveRange(start, &effectiveRange,
        tmpLength, _infoArray, &arrayIndex);
      arrayIndex++;

      if (effectiveRange.location == range.location
	&& effectiveRange.length == range.length)
	{
	  arrayIndex--;
	  if (arrayIndex!=0 || arraySize > 1)
	    {
	      REMOVEAT(arrayIndex);
	      arraySize--;
	    }
	  else
	    {
	      info = OBJECTAT(0);
	      unCacheAttributes(info->attrs);
	      info->attrs = cacheAttributes(blank->attrs);
	      info->loc = NSMaxRange(range);
	    }
	}
    }

  /*
   * Now adjust the positions of the ranges following the one we are using.
   */
  while (arrayIndex < arraySize)
    {
      info = OBJECTAT(arrayIndex);
      info->loc += moveLocations;
      arrayIndex++;
    }
  [_textChars replaceCharactersInRange: range withString: aString];
finish:
SANITY();
}

- (void) dealloc
{
  [_textProxy release];
  RELEASE(_textChars);
  RELEASE(_infoArray);
  [super dealloc];
}

// The superclass implementation is correct but too slow
- (NSUInteger) length
{
  return [_textChars length];
}

@end



@interface	NSGAttributedString : NSAttributedString
@end
@implementation	NSGAttributedString
- (id) initWithCoder: (NSCoder*)aCoder
{
  NSLog(@"Warning - decoding archive containing obsolete %@ object - please delete/replace this archive", NSStringFromClass([self class]));
  DESTROY(self);
  self = (id)NSAllocateObject([GSAttributedString class], 0, NSDefaultMallocZone());
  self = [self initWithCoder: aCoder];
  return self;
}
@end

@interface	NSGMutableAttributedString : NSMutableAttributedString
@end
@implementation	NSGMutableAttributedString
- (id) initWithCoder: (NSCoder*)aCoder
{
  NSLog(@"Warning - decoding archive containing obsolete %@ object - please delete/replace this archive", NSStringFromClass([self class]));
  DESTROY(self);
  self = (id)NSAllocateObject([GSMutableAttributedString class], 0, NSDefaultMallocZone());
  self = [self initWithCoder: aCoder];
  return self;
}
@end