3party/libzmq
0
0
Fork 0
mirror of https://github.com/zeromq/libzmq.git synced 2025-03-19 09:53:51 +00:00
Code Issues Packages Projects Releases Wiki Activity

Problem: mtrie use of non-tail recursion leads to stack overflow

Browse Source 
Solution: convert add and rm functions to iterative algorithms
This commit is contained in:
Luca Boccassi 2020-06-13 15:09:39 +01:00
parent e0e3ce081e
commit ab301ebf79
2 changed files with 432 additions and 327 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
src/generic_mtrie.hpp
View File

@ -84,27 +84,6 @@ template <typename T> class generic_mtrie_t
Arg arg_); Arg arg_);
private: private:
bool add_helper (prefix_t prefix_, size_t size_, value_t *value_);
template <typename Arg>
void rm_helper (value_t *value_,
unsigned char **buff_,
size_t buffsize_,
size_t maxbuffsize_,
void (*func_) (prefix_t data_, size_t size_, Arg arg_),
Arg arg_,
bool call_on_uniq_);
template <typename Arg>
void rm_helper_multiple_subnodes (unsigned char **buff_,
size_t buffsize_,
size_t maxbuffsize_,
void (*func_) (prefix_t data_,
size_t size_,
Arg arg_),
Arg arg_,
bool call_on_uniq_,
value_t *pipe_);
rm_result rm_helper (prefix_t prefix_, size_t size_, value_t *value_);
bool is_redundant () const; bool is_redundant () const;
typedef std::set<value_t *> pipes_t; typedef std::set<value_t *> pipes_t;
@ -113,12 +92,24 @@ template <typename T> class generic_mtrie_t
unsigned char _min; unsigned char _min;
unsigned short _count; unsigned short _count;
unsigned short _live_nodes; unsigned short _live_nodes;
union union _next_t
{ {
class generic_mtrie_t<value_t> *node; class generic_mtrie_t<value_t> *node;
class generic_mtrie_t<value_t> **table; class generic_mtrie_t<value_t> **table;
} _next; } _next;
struct iter
{
generic_mtrie_t<value_t> *node;
generic_mtrie_t<value_t> *next_node;
prefix_t prefix;
size_t size;
unsigned short current_child;
unsigned char new_min;
unsigned char new_max;
bool processed_for_removal;
};
ZMQ_NON_COPYABLE_NOR_MOVABLE (generic_mtrie_t) ZMQ_NON_COPYABLE_NOR_MOVABLE (generic_mtrie_t)
}; };
} }

576
src/generic_mtrie_impl.hpp
View File

@ -35,6 +35,7 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <new> #include <new>
#include <algorithm> #include <algorithm>
#include <list>
#include "err.hpp" #include "err.hpp"
#include "macros.hpp" #include "macros.hpp"
@ -69,85 +70,88 @@ template <typename T> generic_mtrie_t<T>::~generic_mtrie_t ()
template <typename T> template <typename T>
bool generic_mtrie_t<T>::add (prefix_t prefix_, size_t size_, value_t *pipe_) bool generic_mtrie_t<T>::add (prefix_t prefix_, size_t size_, value_t *pipe_)
{ {
return add_helper (prefix_, size_, pipe_); generic_mtrie_t<value_t> *it = this;
}
template <typename T>
bool generic_mtrie_t<T>::add_helper (prefix_t prefix_,
size_t size_,
value_t *pipe_)
{
// We are at the node corresponding to the prefix. We are done.
if (!size_) {
const bool result = !_pipes;
if (!_pipes) {
_pipes = new (std::nothrow) pipes_t;
alloc_assert (_pipes);
}
_pipes->insert (pipe_);
return result;
}
while (size_) {
const unsigned char c = *prefix_; const unsigned char c = *prefix_;
if (c < _min || c >= _min + _count) {
if (c < it->_min || c >= it->_min + it->_count) {
// The character is out of range of currently handled // The character is out of range of currently handled
// characters. We have to extend the table. // characters. We have to extend the table.
if (!_count) { if (!it->_count) {
_min = c; it->_min = c;
_count = 1; it->_count = 1;
_next.node = NULL; it->_next.node = NULL;
} else if (_count == 1) { } else if (it->_count == 1) {
const unsigned char oldc = _min; const unsigned char oldc = it->_min;
generic_mtrie_t *oldp = _next.node; generic_mtrie_t *oldp = it->_next.node;
_count = (_min < c ? c - _min : _min - c) + 1; it->_count = (it->_min < c ? c - it->_min : it->_min - c) + 1;
_next.table = static_cast<generic_mtrie_t **> ( it->_next.table = static_cast<generic_mtrie_t **> (
malloc (sizeof (generic_mtrie_t *) * _count)); malloc (sizeof (generic_mtrie_t *) * it->_count));
alloc_assert (_next.table); alloc_assert (it->_next.table);
for (unsigned short i = 0; i != _count; ++i) for (unsigned short i = 0; i != it->_count; ++i)
_next.table[i] = 0; it->_next.table[i] = 0;
_min = std::min (_min, c); it->_min = std::min (it->_min, c);
_next.table[oldc - _min] = oldp; it->_next.table[oldc - it->_min] = oldp;
} else if (_min < c) { } else if (it->_min < c) {
// The new character is above the current character range. // The new character is above the current character range.
const unsigned short old_count = _count; const unsigned short old_count = it->_count;
_count = c - _min + 1; it->_count = c - it->_min + 1;
_next.table = static_cast<generic_mtrie_t **> ( it->_next.table = static_cast<generic_mtrie_t **> (realloc (
realloc (_next.table, sizeof (generic_mtrie_t *) * _count)); it->_next.table, sizeof (generic_mtrie_t *) * it->_count));
alloc_assert (_next.table); alloc_assert (it->_next.table);
for (unsigned short i = old_count; i != _count; i++) for (unsigned short i = old_count; i != it->_count; i++)
_next.table[i] = NULL; it->_next.table[i] = NULL;
} else { } else {
// The new character is below the current character range. // The new character is below the current character range.
const unsigned short old_count = _count; const unsigned short old_count = it->_count;
_count = (_min + old_count) - c; it->_count = (it->_min + old_count) - c;
_next.table = static_cast<generic_mtrie_t **> ( it->_next.table = static_cast<generic_mtrie_t **> (realloc (
realloc (_next.table, sizeof (generic_mtrie_t *) * _count)); it->_next.table, sizeof (generic_mtrie_t *) * it->_count));
alloc_assert (_next.table); alloc_assert (it->_next.table);
memmove (_next.table + _min - c, _next.table, memmove (it->_next.table + it->_min - c, it->_next.table,
old_count * sizeof (generic_mtrie_t *)); old_count * sizeof (generic_mtrie_t *));
for (unsigned short i = 0; i != _min - c; i++) for (unsigned short i = 0; i != it->_min - c; i++)
_next.table[i] = NULL; it->_next.table[i] = NULL;
_min = c; it->_min = c;
} }
} }
// If next node does not exist, create one. // If next node does not exist, create one.
if (_count == 1) { if (it->_count == 1) {
if (!_next.node) { if (!it->_next.node) {
_next.node = new (std::nothrow) generic_mtrie_t; it->_next.node = new (std::nothrow) generic_mtrie_t;
alloc_assert (_next.node); alloc_assert (it->_next.node);
++_live_nodes; ++(it->_live_nodes);
}
return _next.node->add_helper (prefix_ + 1, size_ - 1, pipe_);
}
if (!_next.table[c - _min]) {
_next.table[c - _min] = new (std::nothrow) generic_mtrie_t;
alloc_assert (_next.table[c - _min]);
++_live_nodes;
}
return _next.table[c - _min]->add_helper (prefix_ + 1, size_ - 1, pipe_);
} }
++prefix_;
--size_;
it = it->_next.node;
} else {
if (!it->_next.table[c - it->_min]) {
it->_next.table[c - it->_min] =
new (std::nothrow) generic_mtrie_t;
alloc_assert (it->_next.table[c - it->_min]);
++(it->_live_nodes);
}
++prefix_;
--size_;
it = it->_next.table[c - it->_min];
}
}
// We are at the node corresponding to the prefix. We are done.
const bool result = !it->_pipes;
if (!it->_pipes) {
it->_pipes = new (std::nothrow) pipes_t;
alloc_assert (it->_pipes);
}
it->_pipes->insert (pipe_);
return result;
}
template <typename T> template <typename T>
template <typename Arg> template <typename Arg>
@ -158,97 +162,127 @@ void generic_mtrie_t<T>::rm (value_t *pipe_,
Arg arg_, Arg arg_,
bool call_on_uniq_) bool call_on_uniq_)
{ {
// This used to be implemented as a non-tail recursive travesal of the trie,
// which means remote clients controlled the depth of the recursion and the
// stack size.
// To simulate the non-tail recursion, with post-recursion changes depending on
// the result of the recursive call, a stack is used to re-visit the same node
// and operate on it again after children have been visisted.
// A boolean is used to record whether the node had already been visited and to
// determine if the pre- or post- children visit actions have to be taken.
// In the case of a node with (N > 1) children, the node has to be re-visited
// N times, in the correct order after each child visit.
std::list<struct iter> stack;
unsigned char *buff = NULL; unsigned char *buff = NULL;
rm_helper (pipe_, &buff, 0, 0, func_, arg_, call_on_uniq_); size_t maxbuffsize = 0;
free (buff); struct iter it = {this, NULL, NULL, 0, 0, 0, false};
} stack.push_back (it);
template <typename T> while (!stack.empty ()) {
template <typename Arg> it = stack.back ();
void generic_mtrie_t<T>::rm_helper (value_t *pipe_, stack.pop_back ();
unsigned char **buff_,
size_t buffsize_, if (!it.processed_for_removal) {
size_t maxbuffsize_,
void (*func_) (prefix_t data_,
size_t size_,
Arg arg_),
Arg arg_,
bool call_on_uniq_)
{
// Remove the subscription from this node. // Remove the subscription from this node.
if (_pipes && _pipes->erase (pipe_)) { if (it.node->_pipes && it.node->_pipes->erase (pipe_)) {
if (!call_on_uniq_ || _pipes->empty ()) { if (!call_on_uniq_ || it.node->_pipes->empty ()) {
func_ (*buff_, buffsize_, arg_); func_ (buff, it.size, arg_);
} }
if (_pipes->empty ()) { if (it.node->_pipes->empty ()) {
LIBZMQ_DELETE (_pipes); LIBZMQ_DELETE (it.node->_pipes);
} }
} }
// Adjust the buffer. // Adjust the buffer.
if (buffsize_ >= maxbuffsize_) { if (it.size >= maxbuffsize) {
maxbuffsize_ = buffsize_ + 256; maxbuffsize = it.size + 256;
*buff_ = static_cast<unsigned char *> (realloc (*buff_, maxbuffsize_)); buff =
alloc_assert (*buff_); static_cast<unsigned char *> (realloc (buff, maxbuffsize));
alloc_assert (buff);
} }
switch (_count) { switch (it.node->_count) {
case 0: case 0:
// If there are no subnodes in the trie, return. // If there are no subnodes in the trie, we are done with this node
// pre-processing.
break;
case 1: {
// If there's one subnode (optimisation).
buff[it.size] = it.node->_min;
// Mark this node as pre-processed and push it, so that the next
// visit after the operation on the child can do the removals.
it.processed_for_removal = true;
stack.push_back (it);
struct iter next = {
it.node->_next.node, NULL, NULL, ++it.size, 0, 0, false};
stack.push_back (next);
break;
}
default: {
// If there are multiple subnodes.
// When first visiting this node, initialize the new_min/max parameters
// which will then be used after each child has been processed, on the
// post-children iterations.
if (it.current_child == 0) {
// New min non-null character in the node table after the removal
it.new_min = it.node->_min + it.node->_count - 1;
// New max non-null character in the node table after the removal
it.new_max = it.node->_min;
}
// Mark this node as pre-processed and push it, so that the next
// visit after the operation on the child can do the removals.
buff[it.size] = it.node->_min + it.current_child;
it.processed_for_removal = true;
stack.push_back (it);
if (it.node->_next.table[it.current_child]) {
struct iter next = {
it.node->_next.table[it.current_child],
NULL,
NULL,
it.size + 1,
0,
0,
false};
stack.push_back (next);
}
}
}
} else {
// Reset back for the next time, in case this node doesn't get deleted.
// This is done unconditionally, unlike when setting this variable to true.
it.processed_for_removal = false;
switch (it.node->_count) {
case 0:
// If there are no subnodes in the trie, we are done with this node
// post-processing.
break; break;
case 1: case 1:
// If there's one subnode (optimisation). // If there's one subnode (optimisation).
(*buff_)[buffsize_] = _min;
buffsize_++;
_next.node->rm_helper (pipe_, buff_, buffsize_, maxbuffsize_, func_,
arg_, call_on_uniq_);
// Prune the node if it was made redundant by the removal // Prune the node if it was made redundant by the removal
if (_next.node->is_redundant ()) { if (it.node->_next.node->is_redundant ()) {
LIBZMQ_DELETE (_next.node); LIBZMQ_DELETE (it.node->_next.node);
_count = 0; it.node->_count = 0;
--_live_nodes; --it.node->_live_nodes;
zmq_assert (_live_nodes == 0); zmq_assert (it.node->_live_nodes == 0);
} }
break; break;
default: default:
// If there are multiple subnodes. // If there are multiple subnodes.
rm_helper_multiple_subnodes (buff_, buffsize_, maxbuffsize_, func_,
arg_, call_on_uniq_, pipe_);
break;
}
}
template <typename T>
template <typename Arg>
void generic_mtrie_t<T>::rm_helper_multiple_subnodes (
unsigned char **buff_,
size_t buffsize_,
size_t maxbuffsize_,
void (*func_) (prefix_t data_, size_t size_, Arg arg_),
Arg arg_,
bool call_on_uniq_,
value_t *pipe_)
{ {
// New min non-null character in the node table after the removal if (it.node->_next.table[it.current_child]) {
unsigned char new_min = _min + _count - 1;
// New max non-null character in the node table after the removal
unsigned char new_max = _min;
for (unsigned short c = 0; c != _count; c++) {
(*buff_)[buffsize_] = _min + c;
if (_next.table[c]) {
_next.table[c]->rm_helper (pipe_, buff_, buffsize_ + 1,
maxbuffsize_, func_, arg_,
call_on_uniq_);
// Prune redundant nodes from the mtrie // Prune redundant nodes from the mtrie
if (_next.table[c]->is_redundant ()) { if (it.node->_next.table[it.current_child]
LIBZMQ_DELETE (_next.table[c]); ->is_redundant ()) {
LIBZMQ_DELETE (
it.node->_next.table[it.current_child]);
zmq_assert (_live_nodes > 0); zmq_assert (it.node->_live_nodes > 0);
--_live_nodes; --it.node->_live_nodes;
} else { } else {
// The node is not redundant, so it's a candidate for being // The node is not redundant, so it's a candidate for being
// the new min/max node. // the new min/max node.
@ -257,22 +291,40 @@ void generic_mtrie_t<T>::rm_helper_multiple_subnodes (
// first non-null, non-redundant node encountered is the new // first non-null, non-redundant node encountered is the new
// minimum index. Conversely, the last non-redundant, non-null // minimum index. Conversely, the last non-redundant, non-null
// node encountered is the new maximum index. // node encountered is the new maximum index.
if (c + _min < new_min) if (it.current_child + it.node->_min
new_min = c + _min; < it.new_min)
if (c + _min > new_max) it.new_min =
new_max = c + _min; it.current_child + it.node->_min;
} if (it.current_child + it.node->_min
> it.new_max)
it.new_max =
it.current_child + it.node->_min;
} }
} }
zmq_assert (_count > 1); // If there are more children to visit, push again the current
// node, so that pre-processing can happen on the next child.
// If we are done, reset the child index so that the ::rm is
// fully idempotent.
++it.current_child;
if (it.current_child >= it.node->_count)
it.current_child = 0;
else {
stack.push_back (it);
continue;
}
// All children have been visited and removed if needed, and
// all pre- and post-visit operations have been carried.
// Resize/free the node table if needed.
zmq_assert (it.node->_count > 1);
// Free the node table if it's no longer used. // Free the node table if it's no longer used.
switch (_live_nodes) { switch (it.node->_live_nodes) {
case 0: case 0:
free (_next.table); free (it.node->_next.table);
_next.table = NULL; it.node->_next.table = NULL;
_count = 0; it.node->_count = 0;
break; break;
case 1: case 1:
// Compact the node table if possible // Compact the node table if possible
@ -280,142 +332,204 @@ void generic_mtrie_t<T>::rm_helper_multiple_subnodes (
// If there's only one live node in the table we can // If there's only one live node in the table we can
// switch to using the more compact single-node // switch to using the more compact single-node
// representation // representation
zmq_assert (new_min == new_max); zmq_assert (it.new_min == it.new_max);
zmq_assert (new_min >= _min && new_min < _min + _count); zmq_assert (it.new_min >= it.node->_min);
zmq_assert (it.new_min
< it.node->_min + it.node->_count);
{ {
generic_mtrie_t *node = _next.table[new_min - _min]; generic_mtrie_t *node =
it.node->_next
.table[it.new_min - it.node->_min];
zmq_assert (node); zmq_assert (node);
free (_next.table); free (it.node->_next.table);
_next.node = node; it.node->_next.node = node;
} }
_count = 1; it.node->_count = 1;
_min = new_min; it.node->_min = it.new_min;
break; break;
default: default:
if (new_min > _min || new_max < _min + _count - 1) { if (it.new_min > it.node->_min
zmq_assert (new_max - new_min + 1 > 1); || it.new_max < it.node->_min
+ it.node->_count - 1) {
zmq_assert (it.new_max - it.new_min + 1
> 1);
generic_mtrie_t **old_table = _next.table; generic_mtrie_t **old_table =
zmq_assert (new_min > _min || new_max < _min + _count - 1); it.node->_next.table;
zmq_assert (new_min >= _min); zmq_assert (it.new_min > it.node->_min
zmq_assert (new_max <= _min + _count - 1); || it.new_max
zmq_assert (new_max - new_min + 1 < _count); < it.node->_min
+ it.node->_count - 1);
zmq_assert (it.new_min >= it.node->_min);
zmq_assert (it.new_max
<= it.node->_min
+ it.node->_count - 1);
zmq_assert (it.new_max - it.new_min + 1
< it.node->_count);
_count = new_max - new_min + 1; it.node->_count =
_next.table = static_cast<generic_mtrie_t **> ( it.new_max - it.new_min + 1;
malloc (sizeof (generic_mtrie_t *) * _count)); it.node->_next.table =
alloc_assert (_next.table); static_cast<generic_mtrie_t **> (
malloc (sizeof (generic_mtrie_t *)
* it.node->_count));
alloc_assert (it.node->_next.table);
memmove (_next.table, old_table + (new_min - _min), memmove (it.node->_next.table,
sizeof (generic_mtrie_t *) * _count); old_table
+ (it.new_min - it.node->_min),
sizeof (generic_mtrie_t *)
* it.node->_count);
free (old_table); free (old_table);
_min = new_min; it.node->_min = it.new_min;
} }
} }
} }
}
}
}
free (buff);
}
template <typename T> template <typename T>
typename generic_mtrie_t<T>::rm_result typename generic_mtrie_t<T>::rm_result
generic_mtrie_t<T>::rm (prefix_t prefix_, size_t size_, value_t *pipe_) generic_mtrie_t<T>::rm (prefix_t prefix_, size_t size_, value_t *pipe_)
{ {
return rm_helper (prefix_, size_, pipe_); // This used to be implemented as a non-tail recursive travesal of the trie,
// which means remote clients controlled the depth of the recursion and the
// stack size.
// To simulate the non-tail recursion, with post-recursion changes depending on
// the result of the recursive call, a stack is used to re-visit the same node
// and operate on it again after children have been visisted.
// A boolean is used to record whether the node had already been visited and to
// determine if the pre- or post- children visit actions have to be taken.
rm_result ret = not_found;
std::list<struct iter> stack;
struct iter it = {this, NULL, prefix_, size_, 0, 0, 0, false};
stack.push_back (it);
while (!stack.empty ()) {
it = stack.back ();
stack.pop_back ();
if (!it.processed_for_removal) {
if (!it.size) {
if (!it.node->_pipes) {
ret = not_found;
continue;
} }
template <typename T> typename pipes_t::size_type erased =
typename generic_mtrie_t<T>::rm_result it.node->_pipes->erase (pipe_);
generic_mtrie_t<T>::rm_helper (prefix_t prefix_, size_t size_, value_t *pipe_) if (it.node->_pipes->empty ()) {
{
if (!size_) {
if (!_pipes)
return not_found;
typename pipes_t::size_type erased = _pipes->erase (pipe_);
if (_pipes->empty ()) {
zmq_assert (erased == 1); zmq_assert (erased == 1);
LIBZMQ_DELETE (_pipes); LIBZMQ_DELETE (it.node->_pipes);
return last_value_removed; ret = last_value_removed;
} continue;
return (erased == 1) ? values_remain : not_found;
} }
const unsigned char c = *prefix_; ret = (erased == 1) ? values_remain : not_found;
if (!_count || c < _min || c >= _min + _count) continue;
return not_found; }
generic_mtrie_t *next_node = it.current_child = *it.prefix;
_count == 1 ? _next.node : _next.table[c - _min]; if (!it.node->_count || it.current_child < it.node->_min
|| it.current_child >= it.node->_min + it.node->_count) {
ret = not_found;
continue;
}
if (!next_node) it.next_node =
return not_found; it.node->_count == 1
? it.node->_next.node
: it.node->_next.table[it.current_child - it.node->_min];
if (!it.next_node) {
ret = not_found;
continue;
}
const rm_result ret = next_node->rm_helper (prefix_ + 1, size_ - 1, pipe_); it.processed_for_removal = true;
stack.push_back (it);
if (next_node->is_redundant ()) { struct iter next = {
LIBZMQ_DELETE (next_node); it.next_node, NULL, it.prefix + 1, it.size - 1, 0, 0, 0, false};
zmq_assert (_count > 0); stack.push_back (next);
if (_count == 1) {
_next.node = 0;
_count = 0;
--_live_nodes;
zmq_assert (_live_nodes == 0);
} else { } else {
_next.table[c - _min] = 0; it.processed_for_removal = false;
zmq_assert (_live_nodes > 1);
--_live_nodes; if (it.next_node->is_redundant ()) {
LIBZMQ_DELETE (it.next_node);
zmq_assert (it.node->_count > 0);
if (it.node->_count == 1) {
it.node->_next.node = NULL;
it.node->_count = 0;
--it.node->_live_nodes;
zmq_assert (it.node->_live_nodes == 0);
} else {
it.node->_next.table[it.current_child - it.node->_min] = 0;
zmq_assert (it.node->_live_nodes > 1);
--it.node->_live_nodes;
// Compact the table if possible // Compact the table if possible
if (_live_nodes == 1) { if (it.node->_live_nodes == 1) {
// If there's only one live node in the table we can // If there's only one live node in the table we can
// switch to using the more compact single-node // switch to using the more compact single-node
// representation // representation
unsigned short i; unsigned short i;
for (i = 0; i < _count; ++i) for (i = 0; i < it.node->_count; ++i)
if (_next.table[i]) if (it.node->_next.table[i])
break; break;
zmq_assert (i < _count); zmq_assert (i < it.node->_count);
_min += i; it.node->_min += i;
_count = 1; it.node->_count = 1;
generic_mtrie_t *oldp = _next.table[i]; generic_mtrie_t *oldp = it.node->_next.table[i];
free (_next.table); free (it.node->_next.table);
_next.node = oldp; it.node->_next.table = NULL;
} else if (c == _min) { it.node->_next.node = oldp;
} else if (it.current_child == it.node->_min) {
// We can compact the table "from the left" // We can compact the table "from the left"
unsigned short i; unsigned short i;
for (i = 1; i < _count; ++i) for (i = 1; i < it.node->_count; ++i)
if (_next.table[i]) if (it.node->_next.table[i])
break; break;
zmq_assert (i < _count); zmq_assert (i < it.node->_count);
_min += i; it.node->_min += i;
_count -= i; it.node->_count -= i;
generic_mtrie_t **old_table = _next.table; generic_mtrie_t **old_table = it.node->_next.table;
_next.table = static_cast<generic_mtrie_t **> ( it.node->_next.table =
malloc (sizeof (generic_mtrie_t *) * _count)); static_cast<generic_mtrie_t **> (malloc (
alloc_assert (_next.table); sizeof (generic_mtrie_t *) * it.node->_count));
memmove (_next.table, old_table + i, alloc_assert (it.node->_next.table);
sizeof (generic_mtrie_t *) * _count); memmove (it.node->_next.table, old_table + i,
sizeof (generic_mtrie_t *) * it.node->_count);
free (old_table); free (old_table);
} else if (c == _min + _count - 1) { } else if (it.current_child
== it.node->_min + it.node->_count - 1) {
// We can compact the table "from the right" // We can compact the table "from the right"
unsigned short i; unsigned short i;
for (i = 1; i < _count; ++i) for (i = 1; i < it.node->_count; ++i)
if (_next.table[_count - 1 - i]) if (it.node->_next.table[it.node->_count - 1 - i])
break; break;
zmq_assert (i < _count); zmq_assert (i < it.node->_count);
_count -= i; it.node->_count -= i;
generic_mtrie_t **old_table = _next.table; generic_mtrie_t **old_table = it.node->_next.table;
_next.table = static_cast<generic_mtrie_t **> ( it.node->_next.table =
malloc (sizeof (generic_mtrie_t *) * _count)); static_cast<generic_mtrie_t **> (malloc (
alloc_assert (_next.table); sizeof (generic_mtrie_t *) * it.node->_count));
memmove (_next.table, old_table, alloc_assert (it.node->_next.table);
sizeof (generic_mtrie_t *) * _count); memmove (it.node->_next.table, old_table,
sizeof (generic_mtrie_t *) * it.node->_count);
free (old_table); free (old_table);
} }
} }
} }
}
}
return ret; return ret;
} }