/*

 * Copyright (c) 1996,1997

 * Silicon Graphics Computer Systems, Inc.

 *

 * Copyright (c) 1999

 * Boris Fomitchev

 *

 * This material is provided "as is", with absolutely no warranty expressed

 * or implied. Any use is at your own risk.

 *

 * Permission to use or copy this software for any purpose is hereby granted

 * without fee, provided the above notices are retained on all copies.

 * Permission to modify the code and to distribute modified code is granted,

 * provided the above notices are retained, and a notice that the code was

 * modified is included with the above copyright notice.

 *

 */

/* NOTE: This is an internal header file, included by other STL headers.

 *   You should not attempt to use it directly.

 */

// Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf

// if necessary.  Assumes path_end[leaf_index] and leaf_pos are correct.

// Results in a valid buf_ptr if the iterator can be legitimately

// dereferenced.

#ifndef _STLP_ROPEIMPL_H

#define _STLP_ROPEIMPL_H

#ifndef _STLP_INTERNAL_ROPE_H

#  include <stl/_rope.h>

#endif

#ifndef _STLP_INTERNAL_CSTDIO

#  include <stl/_cstdio.h>

#endif

#if !defined (_STLP_USE_NO_IOSTREAMS)

#  ifndef _STLP_IOSTREAM

#    include <iostream>

#  endif

#endif

#include <stl/_range_errors.h>

_STLP_BEGIN_NAMESPACE

# if defined ( _STLP_NESTED_TYPE_PARAM_BUG )

# define __allocator__ _Alloc

# else

# define __allocator__ allocator_type

# endif

template<class _CharT, class _Alloc>

_Rope_iterator<_CharT, _Alloc>::_Rope_iterator(rope<_CharT,_Alloc>* __r, size_t __pos)

  : _Rope_iterator_base<_CharT,_Alloc>(__r->_M_tree_ptr._M_data, __pos),

  _M_root_rope(__r) { _RopeRep::_S_ref(this->_M_root); }

template<class _CharT, class _Alloc>

_Rope_iterator<_CharT, _Alloc>::_Rope_iterator(rope<_CharT,_Alloc>& __r, size_t __pos):

  _Rope_iterator_base<_CharT,_Alloc>(__r._M_tree_ptr._M_data, __pos),

  _M_root_rope(&__r) {

#if !defined (__DMC__)

  _RopeRep::_S_ref(this->_M_root); if (!(__r.empty()))_S_setcache(*this);

#else

  _Rope_iterator_base<_CharT, _Alloc>* __x = this;

  _RopeRep::_S_ref(this->_M_root); if (!(__r.empty()))_S_setcache(*__x);

#endif

}

template<class _CharT, class _Alloc>

void _Rope_RopeRep<_CharT, _Alloc>::_M_free_c_string() {

  _CharT* __cstr = _M_c_string;

  if (0 != __cstr) {

    size_t _p_size = _M_size._M_data + 1;

    _STLP_STD::_Destroy_Range(__cstr, __cstr + _p_size);

    _M_size.deallocate(__cstr, _p_size);

  }

}

// Set buf_start, buf_end, and buf_ptr appropriately, filling tmp_buf

// if necessary.  Assumes _M_path_end[leaf_index] and leaf_pos are correct.

// Results in a valid buf_ptr if the iterator can be legitimately

// dereferenced.

template <class _CharT, class _Alloc>

void _Rope_iterator_base<_CharT,_Alloc>::_S_setbuf(

  _Rope_iterator_base<_CharT,_Alloc>& __x) {

  const _RopeRep* __leaf = __x._M_path_end._M_data[__x._M_leaf_index];

  size_t __leaf_pos = __x._M_leaf_pos;

  size_t __pos = __x._M_current_pos;

  switch(__leaf->_M_tag) {

  case _RopeRep::_S_leaf:

    typedef _Rope_RopeLeaf<_CharT, _Alloc> _RopeLeaf;

    __x._M_buf_start = __STATIC_CAST(const _RopeLeaf*, __leaf)->_M_data;

    __x._M_buf_ptr = __x._M_buf_start + (__pos - __leaf_pos);

    __x._M_buf_end = __x._M_buf_start + __leaf->_M_size._M_data;

    break;

  case _RopeRep::_S_function:

  case _RopeRep::_S_substringfn:

    {

      size_t __len = _S_iterator_buf_len;

      size_t __buf_start_pos = __leaf_pos;

      size_t __leaf_end = __leaf_pos + __leaf->_M_size._M_data;

      typedef _Rope_RopeFunction<_CharT, _Alloc> _RopeFunction;

      char_producer<_CharT>* __fn = __STATIC_CAST(const _RopeFunction*, __leaf)->_M_fn;

      if (__buf_start_pos + __len <= __pos) {

        __buf_start_pos = __pos - __len/4;

        if (__buf_start_pos + __len > __leaf_end) {

          __buf_start_pos = __leaf_end - __len;

        }

      }

      if (__buf_start_pos + __len > __leaf_end) {

        __len = __leaf_end - __buf_start_pos;

      }

      (*__fn)(__buf_start_pos - __leaf_pos, __len, __x._M_tmp_buf._M_data);

      __x._M_buf_ptr = __x._M_tmp_buf._M_data + (__pos - __buf_start_pos);

      __x._M_buf_start = __x._M_tmp_buf._M_data;

      __x._M_buf_end = __x._M_tmp_buf._M_data + __len;

    }

    break;

  default:

      _STLP_ASSERT(0)

      ;

  }

}

// Set path and buffer inside a rope iterator.  We assume that

// pos and root are already set.

template <class _CharT, class _Alloc>

void _Rope_iterator_base<_CharT,_Alloc>::_S_setcache(

  _Rope_iterator_base<_CharT,_Alloc>& __x) {

  const _RopeRep* __path[_RopeRep::_S_max_rope_depth+1];

  const _RopeRep* __curr_rope;

  int __curr_depth = -1;  /* index into path    */

  size_t __curr_start_pos = 0;

  size_t __pos = __x._M_current_pos;

  unsigned char __dirns = 0; // Bit vector marking right turns in the path

  _STLP_ASSERT(__pos <= __x._M_root->_M_size._M_data)

  if (__pos >= __x._M_root->_M_size._M_data) {

    __x._M_buf_ptr = 0;

    return;

  }

  __curr_rope = __x._M_root;

  if (0 != __curr_rope->_M_c_string) {

    /* Treat the root as a leaf. */

    __x._M_buf_start = __curr_rope->_M_c_string;

    __x._M_buf_end = __curr_rope->_M_c_string + __curr_rope->_M_size._M_data;

    __x._M_buf_ptr = __curr_rope->_M_c_string + __pos;

    __x._M_path_end._M_data[0] = __curr_rope;

    __x._M_leaf_index = 0;

    __x._M_leaf_pos = 0;

    return;

  }

  for(;;) {

    ++__curr_depth;

    _STLP_ASSERT(__curr_depth <= _RopeRep::_S_max_rope_depth)

    __path[__curr_depth] = __curr_rope;

    switch(__curr_rope->_M_tag) {

    case _RopeRep::_S_leaf:

    case _RopeRep::_S_function:

    case _RopeRep::_S_substringfn:

      __x._M_leaf_pos = __curr_start_pos;

      goto done;

    case _RopeRep::_S_concat:

      {

        const _RopeConcat* __c = __STATIC_CAST(const _RopeConcat*, __curr_rope);

        _RopeRep* __left = __c->_M_left;

        size_t __left_len = __left->_M_size._M_data;

        __dirns <<= 1;

        if (__pos >= __curr_start_pos + __left_len) {

          __dirns |= 1;

          __curr_rope = __c->_M_right;

          __curr_start_pos += __left_len;

        } else {

          __curr_rope = __left;

        }

      }

      break;

    }

  }

done:

    // Copy last section of path into _M_path_end.

  {

    int __i = -1;

    int __j = __curr_depth + 1 - _S_path_cache_len;

    if (__j < 0) __j = 0;

    while (__j <= __curr_depth) {

      __x._M_path_end._M_data[++__i] = __path[__j++];

    }

    __x._M_leaf_index = __i;

  }

  __x._M_path_directions = __dirns;

  _S_setbuf(__x);

}

// Specialized version of the above.  Assumes that

// the path cache is valid for the previous position.

template <class _CharT, class _Alloc>

void _Rope_iterator_base<_CharT,_Alloc>::_S_setcache_for_incr(

_Rope_iterator_base<_CharT,_Alloc>& __x) {

  int __current_index = __x._M_leaf_index;

  const _RopeRep* __current_node = __x._M_path_end._M_data[__current_index];

  size_t __len = __current_node->_M_size._M_data;

  size_t __node_start_pos = __x._M_leaf_pos;

  unsigned char __dirns = __x._M_path_directions;

  const _RopeConcat* __c;

  _STLP_ASSERT(__x._M_current_pos <= __x._M_root->_M_size._M_data)

  if (__x._M_current_pos - __node_start_pos < __len) {

    /* More stuff in this leaf, we just didn't cache it. */

    _S_setbuf(__x);

    return;

  }

  _STLP_ASSERT(__node_start_pos + __len == __x._M_current_pos)

    //  node_start_pos is starting position of last_node.

  while (--__current_index >= 0) {

    if (!(__dirns & 1) /* Path turned left */)

      break;

    __current_node = __x._M_path_end._M_data[__current_index];

    __c = __STATIC_CAST(const _RopeConcat*, __current_node);

    // Otherwise we were in the right child.  Thus we should pop

    // the concatenation node.

    __node_start_pos -= __c->_M_left->_M_size._M_data;

    __dirns >>= 1;

  }

  if (__current_index < 0) {

    // We underflowed the cache. Punt.

    _S_setcache(__x);

    return;

  }

  __current_node = __x._M_path_end._M_data[__current_index];

  __c = __STATIC_CAST(const _RopeConcat*, __current_node);

  // current_node is a concatenation node.  We are positioned on the first

  // character in its right child.

  // node_start_pos is starting position of current_node.

  __node_start_pos += __c->_M_left->_M_size._M_data;

  __current_node = __c->_M_right;

  __x._M_path_end._M_data[++__current_index] = __current_node;

  __dirns |= 1;

  while (_RopeRep::_S_concat == __current_node->_M_tag) {

    ++__current_index;

    if (_S_path_cache_len == __current_index) {

      int __i;

      for (__i = 0; __i < _S_path_cache_len-1; ++__i) {

        __x._M_path_end._M_data[__i] = __x._M_path_end._M_data[__i+1];

      }

      --__current_index;

    }

    __current_node = __STATIC_CAST(const _RopeConcat*, __current_node)->_M_left;

    __x._M_path_end._M_data[__current_index] = __current_node;

    __dirns <<= 1;

    // node_start_pos is unchanged.

  }

  __x._M_leaf_index = __current_index;

  __x._M_leaf_pos = __node_start_pos;

  __x._M_path_directions = __dirns;

  _S_setbuf(__x);

}

template <class _CharT, class _Alloc>

void _Rope_iterator_base<_CharT,_Alloc>::_M_incr(size_t __n) {

  _M_current_pos += __n;

  if (0 != _M_buf_ptr) {

    size_t __chars_left = _M_buf_end - _M_buf_ptr;

    if (__chars_left > __n) {

      _M_buf_ptr += __n;

    } else if (__chars_left == __n) {

      _M_buf_ptr += __n;

      _S_setcache_for_incr(*this);

    } else {

      _M_buf_ptr = 0;

    }

  }

}

template <class _CharT, class _Alloc>

void _Rope_iterator_base<_CharT,_Alloc>::_M_decr(size_t __n) {

  if (0 != _M_buf_ptr) {

    size_t __chars_left = _M_buf_ptr - _M_buf_start;

    if (__chars_left >= __n) {

      _M_buf_ptr -= __n;

    } else {

      _M_buf_ptr = 0;

    }

  }

  _M_current_pos -= __n;

}

template <class _CharT, class _Alloc>

void _Rope_iterator<_CharT,_Alloc>::_M_check() {

  if (_M_root_rope->_M_tree_ptr._M_data != this->_M_root) {

    // _Rope was modified.  Get things fixed up.

    _RopeRep::_S_unref(this->_M_root);

    this->_M_root = _M_root_rope->_M_tree_ptr._M_data;

    _RopeRep::_S_ref(this->_M_root);

    this->_M_buf_ptr = 0;

  }

}

//  There are several reasons for not doing this with virtual destructors

//  and a class specific delete operator:

//  - A class specific delete operator can't easily get access to

//    allocator instances if we need them.

//  - Any virtual function would need a 4 or byte vtable pointer;

//    this only requires a one byte tag per object.

template <class _CharT, class _Alloc>

void _Rope_RopeRep<_CharT,_Alloc>::_M_free_tree() {

  switch (_M_tag) {

  case _S_leaf:

    {

      typedef _Rope_RopeLeaf<_CharT, _Alloc> _RopeLeaf;

      _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, this);

      _STLP_STD::_Destroy(__l); // ->_Rope_RopeLeaf<_CharT,_Alloc>::~_Rope_RopeLeaf();

      _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_size,

                             _RopeLeaf).deallocate(__l, 1);

      break;

    }

  case _S_concat:

    {

      typedef _Rope_RopeConcatenation<_CharT, _Alloc> _RopeConcatenation;

      _RopeConcatenation* __c  = __STATIC_CAST(_RopeConcatenation*, this);

      _STLP_STD::_Destroy(__c);

      _STLP_CREATE_ALLOCATOR(allocator_type,(const allocator_type&)_M_size,

                             _RopeConcatenation).deallocate(__c, 1);

      break;

    }

  case _S_function:

    {

      typedef _Rope_RopeFunction<_CharT, _Alloc> _RopeFunction;

      _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, this);

      _STLP_STD::_Destroy(__f);

      _STLP_CREATE_ALLOCATOR(allocator_type, (const allocator_type&)_M_size,

                             _RopeFunction).deallocate(__f, 1);

      break;

    }

  case _S_substringfn:

    {

      typedef _Rope_RopeSubstring<_CharT, _Alloc> _RopeSubstring;

      _RopeSubstring* __rss = __STATIC_CAST(_RopeSubstring*, this);

      _STLP_STD::_Destroy(__rss);

      _STLP_CREATE_ALLOCATOR(allocator_type, (const allocator_type&)_M_size,

                             _RopeSubstring).deallocate(__rss, 1);

      break;

    }

  }

}

# if defined ( _STLP_NESTED_TYPE_PARAM_BUG )

#   define __RopeLeaf__ _Rope_RopeLeaf<_CharT,_Alloc>

#   define __RopeRep__ _Rope_RopeRep<_CharT,_Alloc>

#   define _RopeLeaf _Rope_RopeLeaf<_CharT,_Alloc>

#   define _RopeRep _Rope_RopeRep<_CharT,_Alloc>

#   define size_type size_t

# else

#   define __RopeLeaf__ _STLP_TYPENAME_ON_RETURN_TYPE rope<_CharT,_Alloc>::_RopeLeaf

#   define __RopeRep__ _STLP_TYPENAME_ON_RETURN_TYPE rope<_CharT,_Alloc>::_RopeRep

# endif

template <class _CharT, class _Alloc>

void rope<_CharT, _Alloc>::_M_throw_out_of_range() const {

  __stl_throw_out_of_range("rope");

}

// Concatenate a C string onto a leaf rope by copying the rope data.

// Used for short ropes.

template <class _CharT, class _Alloc>

__RopeLeaf__*

rope<_CharT,_Alloc>::_S_leaf_concat_char_iter (

  _RopeLeaf* __r, const _CharT* __iter, size_t __len) {

  size_t __old_len = __r->_M_size._M_data;

  _CharT* __new_data = __r->_M_size.allocate(_S_rounded_up_size(__old_len + __len));

  _RopeLeaf* __result;

  _STLP_PRIV __ucopy_n(__r->_M_data, __old_len, __new_data);

  _STLP_PRIV __ucopy_n(__iter, __len, __new_data + __old_len);

  _S_construct_null(__new_data + __old_len + __len);

  _STLP_TRY {

    __result = _S_new_RopeLeaf(__new_data, __old_len + __len, __r->get_allocator());

  }

  _STLP_UNWIND(_RopeRep::_S_free_string(__new_data, __old_len + __len,

                                        __r->get_allocator()))

  return __result;

}

template <class _CharT, class _Alloc>

void _Terminate_RopeLeaf(_Rope_RopeLeaf<_CharT,_Alloc> *__r,

                         size_t __size, const __true_type& /*basic char type*/) {

  _S_construct_null(__r->_M_data + __size);

  _STLP_ASSERT(__r->_M_c_string == __r->_M_data)

}

template <class _CharT, class _Alloc>

void _Terminate_RopeLeaf(_Rope_RopeLeaf<_CharT,_Alloc> *__r,

                         size_t, const __false_type& /*basic char type*/) {

  if (__r->_M_c_string != __r->_M_data && 0 != __r->_M_c_string) {

    __r->_M_free_c_string();

    __r->_M_c_string = 0;

  }

}

// As above, but it's OK to clobber original if refcount is 1

template <class _CharT, class _Alloc>

__RopeLeaf__*

rope<_CharT,_Alloc>::_S_destr_leaf_concat_char_iter (_RopeLeaf* __r, const _CharT* __iter, size_t __len) {

  //_STLP_ASSERT(__r->_M_ref_count >= 1)

  if ( /* __r->_M_ref_count > 1 */  __r->_M_incr() > 2 ) { // - ptr

    __r->_M_decr(); // - ptr

    return _S_leaf_concat_char_iter(__r, __iter, __len);

  }

  __r->_M_decr(); // - ptr, __r->_M_ref_count == 1 or 0

  size_t __old_len = __r->_M_size._M_data;

  if (_S_rounded_up_size(__old_len) == _S_rounded_up_size(__old_len + __len)) {

    // The space has been partially initialized for the standard

    // character types.  But that doesn't matter for those types.

    _STLP_PRIV __ucopy_n(__iter, __len, __r->_M_data + __old_len);

    _Terminate_RopeLeaf(__r, __old_len + __len, _IsBasicCharType());

    __r->_M_size._M_data = __old_len + __len;

    // _STLP_ASSERT(__r->_M_ref_count == 1)

    // __r->_M_ref_count = 2;

    __r->_M_incr(); // i.e.  __r->_M_ref_count = 2

    return __r;

  } else {

    _RopeLeaf* __result = _S_leaf_concat_char_iter(__r, __iter, __len);

    //_STLP_ASSERT(__result->_M_ref_count == 1)

    return __result;

  }

}

// Assumes left and right are not 0.

// Does not increment (nor decrement on exception) child reference counts.

// Result has ref count 1.

template <class _CharT, class _Alloc>

__RopeRep__*

rope<_CharT,_Alloc>::_S_tree_concat (_RopeRep* __left, _RopeRep* __right) {

  _RopeConcatenation* __result =

    _S_new_RopeConcatenation(__left, __right, __left->get_allocator());

  size_t __depth = __result->_M_depth;

  _STLP_ASSERT(__left->get_allocator() == __right->get_allocator())

  if (__depth > 20 && (__result->_M_size._M_data < 1000 ||

      __depth > _RopeRep::_S_max_rope_depth)) {

    _RopeRep* __balanced;

    _STLP_TRY {

      __balanced = _S_balance(__result);

     // _STLP_ASSERT(__result == __balanced ||

     //              1 == __result->_M_ref_count &&

     //              1 == __balanced->_M_ref_count)

      __result->_M_unref_nonnil();

    }

    _STLP_UNWIND((_STLP_CREATE_ALLOCATOR(allocator_type,(allocator_type&)__left->_M_size,

                                         _RopeConcatenation).deallocate(__result,1)))

    // In case of exception, we need to deallocate

    // otherwise dangling result node.  But caller

    // still owns its children.  Thus unref is

    // inappropriate.

    return __balanced;

  } else {

    return __result;

  }

}

template <class _CharT, class _Alloc>

__RopeRep__*

rope<_CharT,_Alloc>::_S_concat_char_iter (_RopeRep* __r,

                                          const _CharT*__s, size_t __slen) {

  _RopeRep* __result;

  if (0 == __slen) {

    _S_ref(__r);

    return __r;

  }

  if (0 == __r)

    return _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

  if (_RopeRep::_S_leaf == __r->_M_tag &&

      __r->_M_size._M_data + __slen <= _S_copy_max) {

    __result = _S_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);

    // _STLP_ASSERT(1 == __result->_M_ref_count)

    return __result;

  }

  if (_RopeRep::_S_concat == __r->_M_tag &&

      _RopeRep::_S_leaf == ((_RopeConcatenation*)__r)->_M_right->_M_tag) {

    _RopeLeaf* __right = (_RopeLeaf* )(((_RopeConcatenation* )__r)->_M_right);

    if (__right->_M_size._M_data + __slen <= _S_copy_max) {

      _RopeRep* __left = ((_RopeConcatenation*)__r)->_M_left;

      _RopeRep* __nright = _S_leaf_concat_char_iter((_RopeLeaf*)__right, __s, __slen);

      __left->_M_ref_nonnil();

      _STLP_TRY {

        __result = _S_tree_concat(__left, __nright);

      }

      _STLP_UNWIND(_S_unref(__left); _S_unref(__nright))

      // _STLP_ASSERT(1 == __result->_M_ref_count)

      return __result;

    }

  }

  _RopeRep* __nright =

    _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

  _STLP_TRY {

    __r->_M_ref_nonnil();

    __result = _S_tree_concat(__r, __nright);

  }

  _STLP_UNWIND(_S_unref(__r); _S_unref(__nright))

  // _STLP_ASSERT(1 == __result->_M_ref_count)

  return __result;

}

template <class _CharT, class _Alloc>

__RopeRep__*

rope<_CharT,_Alloc>::_S_destr_concat_char_iter(

  _RopeRep* __r, const _CharT* __s, size_t __slen) {

  _RopeRep* __result;

  if (0 == __r)

    return _S_RopeLeaf_from_unowned_char_ptr(__s, __slen,

                                             __r->get_allocator());

  // size_t __count = __r->_M_ref_count;

  size_t __orig_size = __r->_M_size._M_data;

  // _STLP_ASSERT(__count >= 1)

  if ( /* __count > 1 */ __r->_M_incr() > 2 ) {

    __r->_M_decr();

    return _S_concat_char_iter(__r, __s, __slen);

  }

  if (0 == __slen) {

    return __r;

  }

  __r->_M_decr();

  if (__orig_size + __slen <= _S_copy_max && _RopeRep::_S_leaf == __r->_M_tag) {

    return _S_destr_leaf_concat_char_iter((_RopeLeaf*)__r, __s, __slen);

  }

  if (_RopeRep::_S_concat == __r->_M_tag) {

    _RopeLeaf* __right = __STATIC_CAST(_RopeLeaf*, __STATIC_CAST(_RopeConcatenation*, __r)->_M_right);

    if (_RopeRep::_S_leaf == __right->_M_tag &&

        __right->_M_size._M_data + __slen <= _S_copy_max) {

      _RopeRep* __new_right = _S_destr_leaf_concat_char_iter(__right, __s, __slen);

      if (__right == __new_right) {

        // _STLP_ASSERT(__new_right->_M_ref_count == 2)

        // __new_right->_M_ref_count = 1;

        __new_right->_M_decr();

      } else {

        // _STLP_ASSERT(__new_right->_M_ref_count >= 1)

        __right->_M_unref_nonnil();

      }

      // _STLP_ASSERT(__r->_M_ref_count == 1)

      // __r->_M_ref_count = 2;    // One more than before.

      __r->_M_incr();

      __STATIC_CAST(_RopeConcatenation*, __r)->_M_right = __new_right;

      // E.Musser : moved below

      //    __r->_M_size._M_data = __orig_size + __slen;

      if (0 != __r->_M_c_string) {

        __r->_M_free_c_string();

        __r->_M_c_string = 0;

      }

      __r->_M_size._M_data = __orig_size + __slen;

      return __r;

    }

  }

  _RopeRep* __right =

    _S_RopeLeaf_from_unowned_char_ptr(__s, __slen, __r->get_allocator());

  __r->_M_ref_nonnil();

  _STLP_TRY {

    __result = _S_tree_concat(__r, __right);

  }

  _STLP_UNWIND(_S_unref(__r); _S_unref(__right))

    // _STLP_ASSERT(1 == __result->_M_ref_count)

  return __result;

}

template <class _CharT, class _Alloc>

__RopeRep__*

rope<_CharT,_Alloc>::_S_concat_rep(_RopeRep* __left, _RopeRep* __right) {

  if (0 == __left) {

    _S_ref(__right);

    return __right;

  }

  if (0 == __right) {

    __left->_M_ref_nonnil();

    return __left;

  }

  if (_RopeRep::_S_leaf == __right->_M_tag) {

    if (_RopeRep::_S_leaf == __left->_M_tag) {

      if (__right->_M_size._M_data + __left->_M_size._M_data <= _S_copy_max) {

        return _S_leaf_concat_char_iter(__STATIC_CAST(_RopeLeaf*, __left),

                                        __STATIC_CAST(_RopeLeaf*, __right)->_M_data,

                                        __right->_M_size._M_data);

      }

    } else if (_RopeRep::_S_concat == __left->_M_tag &&

               _RopeRep::_S_leaf == __STATIC_CAST(_RopeConcatenation*, __left)->_M_right->_M_tag) {

      _RopeLeaf* __leftright =

        __STATIC_CAST(_RopeLeaf*, __STATIC_CAST(_RopeConcatenation*, __left)->_M_right);

      if (__leftright->_M_size._M_data + __right->_M_size._M_data <= _S_copy_max) {

        _RopeRep* __leftleft = __STATIC_CAST(_RopeConcatenation*, __left)->_M_left;

        _RopeRep* __rest = _S_leaf_concat_char_iter(__leftright,

                                                    __STATIC_CAST(_RopeLeaf*, __right)->_M_data,

                                                    __right->_M_size._M_data);

        __leftleft->_M_ref_nonnil();

        _STLP_TRY {

          return _S_tree_concat(__leftleft, __rest);

        }

        _STLP_UNWIND(_S_unref(__leftleft); _S_unref(__rest))

      }

    }

  }

  __left->_M_ref_nonnil();

  __right->_M_ref_nonnil();

  _STLP_TRY {

    return _S_tree_concat(__left, __right);

  }

  _STLP_UNWIND(_S_unref(__left); _S_unref(__right))

  _STLP_RET_AFTER_THROW(0)

}

template <class _CharT, class _Alloc>

__RopeRep__*

rope<_CharT,_Alloc>::_S_substring(_RopeRep* __base,

                                  size_t __start, size_t __endp1) {

  if (0 == __base) return 0;

  size_t __len = __base->_M_size._M_data;

  size_t __adj_endp1;

  const size_t __lazy_threshold = 128;

  if (__endp1 >= __len) {

    if (0 == __start) {

      __base->_M_ref_nonnil();

      return __base;

    } else {

      __adj_endp1 = __len;

    }

  } else {

    __adj_endp1 = __endp1;

  }

  switch(__base->_M_tag) {

  case _RopeRep::_S_concat:

  {

    _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __base);

    _RopeRep* __left = __c->_M_left;

    _RopeRep* __right = __c->_M_right;

    size_t __left_len = __left->_M_size._M_data;

    _RopeRep* __result;

    if (__adj_endp1 <= __left_len) {

      return _S_substring(__left, __start, __endp1);

    } else if (__start >= __left_len) {

      return _S_substring(__right, __start - __left_len,

                          __adj_endp1 - __left_len);

    }

    _Self_destruct_ptr __left_result(_S_substring(__left, __start, __left_len));

    _Self_destruct_ptr __right_result(_S_substring(__right, 0, __endp1 - __left_len));

    _STLP_MPWFIX_TRY    //*TY 06/01/2000 - mpw forgets to call dtor on __left_result and __right_result without this try block

    __result = _S_concat_rep(__left_result, __right_result);

    // _STLP_ASSERT(1 == __result->_M_ref_count)

    return __result;

    _STLP_MPWFIX_CATCH    //*TY 06/01/2000 -

  }

  case _RopeRep::_S_leaf:

  {

    _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __base);

    _RopeLeaf* __result;

    size_t __result_len;

    if (__start >= __adj_endp1) return 0;

    __result_len = __adj_endp1 - __start;

    if (__result_len > __lazy_threshold) goto lazy;

    const _CharT* __section = __l->_M_data + __start;

    // We should sometimes create substring node instead.

    __result = _S_RopeLeaf_from_unowned_char_ptr(__section, __result_len,

                                                 __base->get_allocator());

    return __result;

  }

  case _RopeRep::_S_substringfn:

  // Avoid introducing multiple layers of substring nodes.

  {

    _RopeSubstring* __old = __STATIC_CAST(_RopeSubstring*, __base);

    size_t __result_len;

    if (__start >= __adj_endp1) return 0;

    __result_len = __adj_endp1 - __start;

    if (__result_len > __lazy_threshold) {

      _RopeSubstring* __result = _S_new_RopeSubstring(__old->_M_base,

                                                      __start + __old->_M_start,

                                                      __adj_endp1 - __start,

                                                      __base->get_allocator());

      return __result;

    } // *** else fall through: ***

  }

  case _RopeRep::_S_function:

  {

    _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __base);

    if (__start >= __adj_endp1) return 0;

    size_t __result_len = __adj_endp1 - __start;

    if (__result_len > __lazy_threshold) goto lazy;

    _CharT* __section = __base->_M_size.allocate(_S_rounded_up_size(__result_len));

    _STLP_TRY {

      (*(__f->_M_fn))(__start, __result_len, __section);

    }

    _STLP_UNWIND(_RopeRep::_S_free_string(__section,

                                          __result_len, __base->get_allocator()))

    _S_construct_null(__section + __result_len);

    return _S_new_RopeLeaf(__section, __result_len,

                           __base->get_allocator());

  }

  }

  /*NOTREACHED*/

  _STLP_ASSERT(false)

  lazy:

  {

    // Create substring node.

    return _S_new_RopeSubstring(__base, __start, __adj_endp1 - __start,

                                __base->get_allocator());

  }

}

template<class _CharT>

class _Rope_flatten_char_consumer : public _Rope_char_consumer<_CharT> {

private:

  _CharT* _M_buf_ptr;

public:

  _Rope_flatten_char_consumer(_CharT* __buffer) {

    _M_buf_ptr = __buffer;

  }

  ~_Rope_flatten_char_consumer() {}

  bool operator() (const _CharT* __leaf, size_t __n) {

    _STLP_PRIV __ucopy_n(__leaf, __n, _M_buf_ptr);

    _M_buf_ptr += __n;

    return true;

  }

};

template<class _CharT>

class _Rope_find_char_char_consumer : public _Rope_char_consumer<_CharT> {

private:

  _CharT _M_pattern;

public:

  size_t _M_count;  // Number of nonmatching characters

  _Rope_find_char_char_consumer(_CharT __p)

    : _M_pattern(__p), _M_count(0) {}

  ~_Rope_find_char_char_consumer() {}

  bool operator() (const _CharT* __leaf, size_t __n) {

    size_t __i;

    for (__i = 0; __i < __n; ++__i) {

      if (__leaf[__i] == _M_pattern) {

        _M_count += __i; return false;

      }

    }

    _M_count += __n; return true;

  }

};

#if !defined (_STLP_USE_NO_IOSTREAMS)

template<class _CharT, class _Traits>

// Here _CharT is both the stream and rope character type.

class _Rope_insert_char_consumer : public _Rope_char_consumer<_CharT> {

private:

  typedef basic_ostream<_CharT,_Traits> _Insert_ostream;

  typedef _Rope_insert_char_consumer<_CharT,_Traits> _Self;

  _Insert_ostream& _M_o;

  //explicitely defined as private to avoid warnings:

  _Self& operator = (_Self const&);

public:

  _Rope_insert_char_consumer(_Insert_ostream& __writer)

    : _M_o(__writer) {}

#  if defined(__MRC__) || (defined(__SC__) && !defined(__DMC__))  //*TY 05/23/2000 - added support for mpw compiler's trigger function approach to generate vtable

  ~_Rope_insert_char_consumer();    //*TY 05/23/2000 -

#  else    //*TY 05/23/2000 -

  ~_Rope_insert_char_consumer() {}

#  endif    //*TY 05/23/2000 -

  // Caller is presumed to own the ostream

  bool operator() (const _CharT* __leaf, size_t __n);

  // Returns true to continue traversal.

};

#  if defined (__MRC__) || (defined (__SC__) && !defined (__DMC__))    //*TY 05/23/2000 - added support for mpw compiler's trigger function approach to generate vtable

template<class _CharT, class _Traits>

_Rope_insert_char_consumer<_CharT, _Traits>::  ~_Rope_insert_char_consumer() {}

#  endif    //*TY 05/23/2000 -

template<class _CharT, class _Traits>

bool _Rope_insert_char_consumer<_CharT, _Traits>::operator()

  (const _CharT* __leaf, size_t __n) {

  size_t __i;

  //  We assume that formatting is set up correctly for each element.

  for (__i = 0; __i < __n; ++__i) _M_o.put(__leaf[__i]);

  return true;

}

#endif /* !_STLP_USE_NO_IOSTREAMS */

template <class _CharT, class _Alloc, class _CharConsumer>

bool _S_apply_to_pieces(_CharConsumer& __c,

                        _Rope_RopeRep<_CharT, _Alloc> * __r,

                        size_t __begin, size_t __end) {

  typedef _Rope_RopeRep<_CharT, _Alloc> _RopeRep;

  typedef _Rope_RopeConcatenation<_CharT,_Alloc> _RopeConcatenation;

  typedef _Rope_RopeLeaf<_CharT,_Alloc> _RopeLeaf;

  typedef _Rope_RopeFunction<_CharT,_Alloc> _RopeFunction;

  if (0 == __r) return true;

  switch(__r->_M_tag) {

  case _RopeRep::_S_concat:

  {

    _RopeConcatenation* __conc = __STATIC_CAST(_RopeConcatenation*, __r);

    _RopeRep* __left =  __conc->_M_left;

    size_t __left_len = __left->_M_size._M_data;

    if (__begin < __left_len) {

      size_t __left_end = (min) (__left_len, __end);

      if (!_S_apply_to_pieces(__c, __left, __begin, __left_end))

        return false;

    }

    if (__end > __left_len) {

      _RopeRep* __right =  __conc->_M_right;

      size_t __right_start = (max)(__left_len, __begin);

      if (!_S_apply_to_pieces(__c, __right,

                              __right_start - __left_len,

                              __end - __left_len)) {

        return false;

      }

    }

  }

  return true;

  case _RopeRep::_S_leaf:

  {

    _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __r);

    return __c(__l->_M_data + __begin, __end - __begin);

  }

  case _RopeRep::_S_function:

  case _RopeRep::_S_substringfn:

  {

    _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __r);

    size_t __len = __end - __begin;

    bool __result;

    _CharT* __buffer = __r->get_allocator().allocate(__len);

    _STLP_TRY {

      (*(__f->_M_fn))(__begin, __len, __buffer);

      __result = __c(__buffer, __len);

      __r->get_allocator().deallocate(__buffer, __len);

    }

    _STLP_UNWIND((__r->get_allocator().deallocate(__buffer, __len)))

    return __result;

  }

  default:

    _STLP_ASSERT(false)

    /*NOTREACHED*/

    return false;

  }

}

#if !defined (_STLP_USE_NO_IOSTREAMS)

template<class _CharT, class _Traits>

inline void _Rope_fill(basic_ostream<_CharT, _Traits>& __o, streamsize __n) {

  char __f = __o.fill();

  for (streamsize __i = 0; __i < __n; ++__i) __o.put(__f);

}

template<class _CharT, class _Traits, class _Alloc>

basic_ostream<_CharT, _Traits>& _S_io_get(basic_ostream<_CharT, _Traits>& __o,

                                          const rope<_CharT, _Alloc>& __r, const __true_type& /*_IsBasicCharType*/) {

  streamsize __w = __o.width();

  const bool __left = (__o.flags() & ios::left) != 0;

  size_t __rope_len = __r.size();

  _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);

  const bool __need_pad = (((sizeof(streamsize) > sizeof(size_t)) && (__STATIC_CAST(streamsize, __rope_len) < __w)) ||

                           ((sizeof(streamsize) <= sizeof(size_t)) && (__rope_len < __STATIC_CAST(size_t, __w))));

  streamsize __pad_len = __need_pad ? __w - __rope_len : 0;

  if (!__left && __pad_len > 0) {

    _Rope_fill(__o, __pad_len);

  }

  __r.apply_to_pieces(0, __rope_len, __c);

  if (__left && __pad_len > 0) {

    _Rope_fill(__o, __pad_len);

  }

  return __o;

}

template<class _CharT, class _Traits, class _Alloc>

basic_ostream<_CharT, _Traits>& _S_io_get(basic_ostream<_CharT, _Traits>& __o,

                                         const rope<_CharT, _Alloc>& __r, const __false_type& /*_IsBasicCharType*/) {

  streamsize __w = __o.width();

  size_t __rope_len = __r.size();

  _Rope_insert_char_consumer<_CharT, _Traits> __c(__o);

  __o.width(__w /__rope_len);

  _STLP_TRY {

    __r.apply_to_pieces(0, __rope_len, __c);

    __o.width(__w);

  }

  _STLP_UNWIND(__o.width(__w))

  return __o;

}

template<class _CharT, class _Traits, class _Alloc>

basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>& __o,

                                           const rope<_CharT, _Alloc>& __r) {

  typedef typename _IsIntegral<_CharT>::_Ret _Char_Is_Integral;

  return _S_io_get(__o, __r, _Char_Is_Integral());

}

#endif /* NO_IOSTREAMS */

template <class _CharT, class _Alloc>

_CharT* rope<_CharT,_Alloc>::_S_flatten(_RopeRep* __r,

                                        size_t __start, size_t __len,

                                        _CharT* __buffer) {

  _Rope_flatten_char_consumer<_CharT> __c(__buffer);

  _S_apply_to_pieces(__c, __r, __start, __start + __len);

  return(__buffer + __len);

}

template <class _CharT, class _Alloc>

size_t rope<_CharT,_Alloc>::find(_CharT __pattern, size_t __start) const {

  _Rope_find_char_char_consumer<_CharT> __c(__pattern);

  _S_apply_to_pieces(__c, _M_tree_ptr._M_data, __start, size());

  size_type __result_pos = __start + __c._M_count;

#ifndef _STLP_OLD_ROPE_SEMANTICS

  if (__result_pos == size()) __result_pos = npos;

#endif

  return __result_pos;

}

template <class _CharT, class _Alloc>

_CharT*

rope<_CharT,_Alloc>::_S_flatten(_Rope_RopeRep<_CharT, _Alloc>* __r, _CharT* __buffer) {

  if (0 == __r) return __buffer;

  switch(__r->_M_tag) {

  case _RopeRep::_S_concat:

  {

    _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __r);

    _RopeRep* __left = __c->_M_left;

    _RopeRep* __right = __c->_M_right;

    _CharT* __rest = _S_flatten(__left, __buffer);

    return _S_flatten(__right, __rest);

  }

  case _RopeRep::_S_leaf:

  {

    _RopeLeaf* __l = __STATIC_CAST(_RopeLeaf*, __r);

    return _STLP_PRIV __ucopy_n(__l->_M_data, __l->_M_size._M_data, __buffer).second;

  }

  case _RopeRep::_S_function:

  case _RopeRep::_S_substringfn:

  // We dont yet do anything with substring nodes.

  // This needs to be fixed before ropefiles will work well.

  {

    _RopeFunction* __f = __STATIC_CAST(_RopeFunction*, __r);

    (*(__f->_M_fn))(0, __f->_M_size._M_data, __buffer);

    return __buffer + __f->_M_size._M_data;

  }

  default:

    _STLP_ASSERT(false)

    /*NOTREACHED*/

    return 0;

  }

}

#ifdef _STLP_DEBUG

// This needs work for _CharT != char

template <class _CharT, class _Alloc>

void rope<_CharT,_Alloc>::_S_dump(_RopeRep* __r, int __indent) {

  for (int __i = 0; __i < __indent; ++__i) putchar(' ');

  if (0 == __r) {

    printf("NULL\n"); return;

  }

  if (_RopeRep::_S_concat == __r->_M_tag) {

    _RopeConcatenation* __c = __STATIC_CAST(_RopeConcatenation*, __r);

    _RopeRep* __left = __c->_M_left;

    _RopeRep* __right = __c->_M_right;

    printf("Concatenation %p (rc = %ld, depth = %d, len = %ld, %s balanced)\n",

      __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size._M_data,

      __r->_M_is_balanced? "" : "not");

    _S_dump(__left, __indent + 2);

    _S_dump(__right, __indent + 2);

    return;

  }

  else {

    const char* __kind;

    switch (__r->_M_tag) {

      case _RopeRep::_S_leaf:

        __kind = "Leaf";

        break;

      case _RopeRep::_S_function:

        __kind = "Function";

        break;

      case _RopeRep::_S_substringfn:

        __kind = "Function representing substring";

        break;

      default:

        __kind = "(corrupted kind field!)";

    }

    printf("%s %p (rc = %ld, depth = %d, len = %ld) ",

     __kind, __r, __r->_M_ref_count, __r->_M_depth, __r->_M_size._M_data);

    if (sizeof(_CharT) == 1) {

      const int __max_len = 40;