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[Loki-lib-cvs] SF.net SVN: loki-lib:[1005] trunk/include/loki/flex/flex_string_shell.h
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From: <jfb...@us...> - 2009-03-11 17:59:00
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Revision: 1005
http://loki-lib.svn.sourceforge.net/loki-lib/?rev=1005&view=rev
Author: jfbastien
Date: 2009-03-11 17:58:49 +0000 (Wed, 11 Mar 2009)
Log Message:
-----------
Bug 2679853: flex_string cannot insert from current string.
Modified Paths:
--------------
trunk/include/loki/flex/flex_string_shell.h
Modified: trunk/include/loki/flex/flex_string_shell.h
===================================================================
--- trunk/include/loki/flex/flex_string_shell.h 2009-03-10 19:58:26 UTC (rev 1004)
+++ trunk/include/loki/flex/flex_string_shell.h 2009-03-11 17:58:49 UTC (rev 1005)
@@ -388,8 +388,7 @@
{
Invariant checker(*this);
(void) checker;
- static std::less_equal<const value_type*> le;
- if (le(&*begin(), s) && le(s, &*end())) // aliasing
+ if (IsAliasedRange(s, s + n))
{
const size_type offset = s - &*begin();
Storage::reserve(size() + n);
@@ -501,6 +500,46 @@
}
private:
+
+ // Care must be taken when dereferencing some iterator types.
+ //
+ // Users can implement this function in their namespace if their storage uses a special iterator type,
+ // the function will be found through ADL.
+ template<class Iterator>
+ const typename std::iterator_traits<Iterator>::value_type * DereferenceValidIterator(Iterator it) const
+ {
+ return &*it;
+ }
+
+ // Care must be taken when dereferencing a reverse iterators, hence this special case.
+ // This isn't in the std namespace so as not to pollute it or create name clashes.
+ template<typename Iterator>
+ const typename std::iterator_traits<Iterator>::value_type * DereferenceValidIterator(
+ std::reverse_iterator<Iterator> it) const
+ {
+ return &*--it;
+ }
+
+ // Determine if the range aliases the current string.
+ //
+ // This method cannot be const because calling begin/end on copy-on-write implementations must have side effects.
+ // A const version wouldn't make the string unique through this call.
+ template<class Iterator>
+ bool IsAliasedRange(Iterator beginIterator, Iterator endIterator)
+ {
+ if(!empty() && beginIterator != endIterator)
+ {
+ typedef const typename std::iterator_traits<Iterator>::value_type * pointer;
+ pointer myBegin(&*begin());
+ pointer myEnd(&*begin() + size());
+ pointer rangeBegin(DereferenceValidIterator(beginIterator));
+ const std::less_equal<pointer> less_equal = std::less_equal<pointer>();
+ if(less_equal(myBegin, rangeBegin) && less_equal(rangeBegin, myEnd))
+ return true;
+ }
+ return false;
+ }
+
template <int i> class Selector {};
flex_string& InsertImplDiscr(iterator p,
@@ -508,7 +547,7 @@
{
Invariant checker(*this);
(void) checker;
- assert(p >= begin() && p <= end());
+ assert(begin() <= p && p <= end());
if (capacity() - size() < n)
{
const size_type sz = p - begin();
@@ -549,10 +588,24 @@
void InsertImpl(iterator i,
FwdIterator s1, FwdIterator s2, std::forward_iterator_tag)
{
- // TODO: there is a bug in this method when the range to insert is inside the current range. See bug #2679853.
+ if(s1 == s2)
+ {
+ // Insert an empty range.
+ return;
+ }
+ if(IsAliasedRange(s1, s2))
+ {
+ // The source range is contained in the current string, copy it and recurse.
+ const flex_string temporary(s1, s2);
+ InsertImpl(i, temporary.begin(), temporary.end(),
+ typename std::iterator_traits<FwdIterator>::iterator_category());
+ return;
+ }
+
Invariant checker(*this);
(void) checker;
+
const size_type pos = i - begin();
const typename std::iterator_traits<FwdIterator>::difference_type n2 =
std::distance(s1, s2);
@@ -564,10 +617,8 @@
capacity() - size();
if (maxn2 < n2)
{
- // realloc the string
- static const std::less_equal<const value_type*> le =
- std::less_equal<const value_type*>();
- assert(!(le(&*begin(), &*s1) && le(&*s1, &*end())));
+ // Reallocate the string.
+ assert(!IsAliasedRange(s1, s2));
reserve(size() + n2);
i = begin() + pos;
}
@@ -670,8 +721,7 @@
return replace(b, b + n1, s1, s1 + n2);
using namespace flex_string_details;
const int delta = int(n2 - n1);
- static const std::less_equal<const value_type*> le;
- const bool aliased = le(&*begin(), s1) && le(s1, &*end());
+ const bool aliased = IsAliasedRange(s1, s1 + n2);
// From here on we're dealing with an aliased replace
if (delta <= 0)
@@ -811,33 +861,25 @@
std::distance(s1, s2);
assert(n2 >= 0);
- // Make sure the replacement isn't empty.
- if(0 != n2)
+ if (IsAliasedRange(s1, s2))
{
- // Handle aliased replace
- static const std::less_equal<const value_type*> le =
- std::less_equal<const value_type*>();
- const bool aliased = le(&*begin(), &*s1) && le(&*s1, &*end());
- if (aliased /* && capacity() < size() - n1 + n2 */)
- {
- // Aliased replace, copy to new string
- flex_string temp;
- temp.reserve(size() - n1 + n2);
- temp.append(begin(), i1).append(s1, s2).append(i2, end());
- swap(temp);
- return;
- }
+ // Aliased replace, copy to new string.
+ flex_string temporary;
+ temporary.reserve(size() - n1 + n2);
+ temporary.append(begin(), i1).append(s1, s2).append(i2, end());
+ swap(temporary);
+ return;
}
if (n1 > n2)
{
- // shrinks
+ // Shrinks.
std::copy(s1, s2, i1);
erase(i1 + n2, i2);
}
else
{
- // grows
+ // Grows.
flex_string_details::copy_n(s1, n1, i1);
std::advance(s1, n1);
insert(i2, s1, s2);
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