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Added throw if the number of searched states grows too large.

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[SVN r15372]
This commit is contained in:
John Maddock
2002-09-16 11:54:00 +00:00
parent 66ac67533c
commit a7f8f56d92
1 changed files with 42 additions and 4 deletions
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46
include/boost/regex/detail/regex_match.hpp
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@ -26,6 +26,12 @@
#ifndef BOOST_REGEX_MATCH_HPP
#define BOOST_REGEX_MATCH_HPP
#ifndef BOOST_REGEX_MAX_STATE_COUNT
# define BOOST_REGEX_MAX_STATE_COUNT 100000000
#endif
#include <boost/limits.hpp>
namespace boost{
namespace re_detail{
@ -175,6 +181,7 @@ class _priv_match_data
public:
typedef typename boost::detail::rebind_allocator<int, Allocator>::type i_alloc;
typedef typename boost::detail::rebind_allocator<iterator, Allocator>::type it_alloc;
typedef typename regex_iterator_traits<iterator>::difference_type difference_type;
match_results_base<iterator, Allocator> temp_match;
// failure stacks:
@ -184,9 +191,11 @@ public:
jstack<int, Allocator> prev_acc;
int* accumulators;
unsigned int caccumulators;
difference_type state_count;
difference_type max_state_count;
iterator* loop_starts;
_priv_match_data(const match_results_base<iterator, Allocator>&);
_priv_match_data(const match_results_base<iterator, Allocator>&, iterator, iterator, unsigned);
~_priv_match_data()
{
@ -202,15 +211,32 @@ public:
{
return loop_starts;
}
void estimate_max_state_count(iterator a, iterator b, unsigned states, std::random_access_iterator_tag*)
{
difference_type dist = std::distance(a,b);
if(dist > (std::numeric_limits<difference_type>::max() / (states * 3)))
max_state_count = std::numeric_limits<difference_type>::max();
else
max_state_count = states * 3 * dist;
if(max_state_count < 1000)
max_state_count = 1000;
}
void estimate_max_state_count(iterator a, iterator b, unsigned states, void*)
{
// we don't know how long the sequence is:
max_state_count = BOOST_REGEX_MAX_STATE_COUNT;
}
};
template <class iterator, class Allocator>
_priv_match_data<iterator, Allocator>::_priv_match_data(const match_results_base<iterator, Allocator>& m)
_priv_match_data<iterator, Allocator>::_priv_match_data(const match_results_base<iterator, Allocator>& m, iterator a, iterator b, unsigned states)
: temp_match(m), matches(64, m.allocator()), prev_pos(64, m.allocator()), prev_record(64, m.allocator())
{
accumulators = 0;
caccumulators = 0;
loop_starts = 0;
state_count = 0;
estimate_max_state_count(a, b, states, static_cast<regex_iterator_traits<iterator>::iterator_category*>(0));
}
template <class iterator, class Allocator>
@ -297,6 +323,7 @@ bool query_match_aux(iterator first,
typedef typename traits::size_type traits_size_type;
typedef typename traits::uchar_type traits_uchar_type;
typedef typename is_byte<charT>::width_type width_type;
typedef typename re_detail::regex_iterator_traits<iterator>::difference_type difference_type;
// declare some local aliases to reduce pointer loads
// good optimising compilers should make this unnecessary!!
@ -306,6 +333,7 @@ bool query_match_aux(iterator first,
jstack<int, Allocator>& prev_acc = pd.prev_acc;
match_results_base<iterator, Allocator>& temp_match = pd.temp_match;
temp_match.set_first(first);
difference_type& state_count = pd.state_count;
const re_syntax_base* ptr = access::first(e);
bool match_found = false;
@ -337,6 +365,7 @@ bool query_match_aux(iterator first,
while(first != last)
{
jm_assert(ptr);
++state_count;
switch(ptr->type)
{
case syntax_element_match:
@ -816,6 +845,7 @@ bool query_match_aux(iterator first,
while(true)
{
jm_assert(ptr);
++state_count;
switch(ptr->type)
{
case syntax_element_match:
@ -929,6 +959,14 @@ bool query_match_aux(iterator first,
failure:
//
// check to see if we've been searching too many states:
//
if(state_count >= pd.max_state_count)
{
throw std::runtime_error("Max regex search depth exceeded.");
}
//
// check for possible partial match:
//
@ -1177,7 +1215,7 @@ unsigned int reg_grep2(Predicate foo, I first, I last, const reg_expression<char
flags |= match_init;
_priv_match_data<I, A2> pd(m);
_priv_match_data<I, A2> pd(m, first, last, e.size());
const unsigned char* _map = access::get_map(e);
unsigned int type;
@ -1648,7 +1686,7 @@ bool regex_match(iterator first, iterator last, match_results<iterator, Allocato
m.set_line(1, first);
}
flags |= match_all; // must match all of input.
re_detail::_priv_match_data<iterator, Allocator> pd(m);
re_detail::_priv_match_data<iterator, Allocator> pd(m, first, last, e.size());
iterator restart;
bool result = re_detail::query_match_aux(first, last, m, e, flags, pd, &restart);
return result;