generic_mtrie_impl.hpp 14.8 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
/*
Copyright (c) 2018 Contributors as noted in the AUTHORS file

This file is part of libzmq, the ZeroMQ core engine in C++.

libzmq is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

As a special exception, the Contributors give you permission to link
this library with independent modules to produce an executable,
regardless of the license terms of these independent modules, and to
copy and distribute the resulting executable under terms of your choice,
provided that you also meet, for each linked independent module, the
terms and conditions of the license of that module. An independent
module is a module which is not derived from or based on this library.
If you modify this library, you must extend this exception to your
version of the library.

libzmq 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __ZMQ_GENERIC_MTRIE_IMPL_HPP_INCLUDED__
#define __ZMQ_GENERIC_MTRIE_IMPL_HPP_INCLUDED__


#include <stdlib.h>

#include <new>
#include <algorithm>

#include "err.hpp"
#include "pipe.hpp"
#include "macros.hpp"
#include "generic_mtrie.hpp"

template <typename T>
zmq::generic_mtrie_t<T>::generic_mtrie_t () :
    pipes (0),
    min (0),
    count (0),
    live_nodes (0)
{
}

template <typename T> zmq::generic_mtrie_t<T>::~generic_mtrie_t ()
{
    LIBZMQ_DELETE (pipes);

    if (count == 1) {
        zmq_assert (next.node);
        LIBZMQ_DELETE (next.node);
    } else if (count > 1) {
        for (unsigned short i = 0; i != count; ++i) {
            LIBZMQ_DELETE (next.table[i]);
        }
        free (next.table);
    }
}

template <typename T>
bool zmq::generic_mtrie_t<T>::add (prefix_t prefix_,
                                   size_t size_,
                                   value_t *pipe_)
{
    return add_helper (prefix_, size_, pipe_);
}

template <typename T>
bool zmq::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_) {
        bool result = !pipes;
        if (!pipes) {
            pipes = new (std::nothrow) pipes_t;
            alloc_assert (pipes);
        }
        pipes->insert (pipe_);
        return result;
    }

    unsigned char c = *prefix_;
    if (c < min || c >= min + count) {
        //  The character is out of range of currently handled
        //  characters. We have to extend the table.
        if (!count) {
            min = c;
            count = 1;
            next.node = NULL;
        } else if (count == 1) {
            unsigned char oldc = min;
            generic_mtrie_t *oldp = next.node;
            count = (min < c ? c - min : min - c) + 1;
            next.table =
              (generic_mtrie_t **) malloc (sizeof (generic_mtrie_t *) * count);
            alloc_assert (next.table);
            for (unsigned short i = 0; i != count; ++i)
                next.table[i] = 0;
            min = std::min (min, c);
            next.table[oldc - min] = oldp;
        } else if (min < c) {
            //  The new character is above the current character range.
            unsigned short old_count = count;
            count = c - min + 1;
            next.table = (generic_mtrie_t **) realloc (
              next.table, sizeof (generic_mtrie_t *) * count);
            alloc_assert (next.table);
            for (unsigned short i = old_count; i != count; i++)
                next.table[i] = NULL;
        } else {
            //  The new character is below the current character range.
            unsigned short old_count = count;
            count = (min + old_count) - c;
            next.table = (generic_mtrie_t **) realloc (
              next.table, sizeof (generic_mtrie_t *) * count);
            alloc_assert (next.table);
            memmove (next.table + min - c, next.table,
                     old_count * sizeof (generic_mtrie_t *));
            for (unsigned short i = 0; i != min - c; i++)
                next.table[i] = NULL;
            min = c;
        }
    }

    //  If next node does not exist, create one.
    if (count == 1) {
        if (!next.node) {
            next.node = new (std::nothrow) generic_mtrie_t;
            alloc_assert (next.node);
            ++live_nodes;
        }
        return next.node->add_helper (prefix_ + 1, size_ - 1, pipe_);
    } else {
        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_);
    }
}


template <typename T>
155
template <typename Arg>
156 157 158
void zmq::generic_mtrie_t<T>::rm (value_t *pipe_,
                                  void (*func_) (prefix_t data_,
                                                 size_t size_,
159 160
                                                 Arg arg_),
                                  Arg arg_,
161 162 163 164 165 166 167 168
                                  bool call_on_uniq_)
{
    unsigned char *buff = NULL;
    rm_helper (pipe_, &buff, 0, 0, func_, arg_, call_on_uniq_);
    free (buff);
}

template <typename T>
169
template <typename Arg>
170
void zmq::generic_mtrie_t<T>::rm_helper (value_t *pipe_,
171 172 173 174 175
                                         unsigned char **buff_,
                                         size_t buffsize_,
                                         size_t maxbuffsize_,
                                         void (*func_) (prefix_t data_,
                                                        size_t size_,
176 177
                                                        Arg arg_),
                                         Arg arg_,
178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296
                                         bool call_on_uniq_)
{
    //  Remove the subscription from this node.
    if (pipes && pipes->erase (pipe_)) {
        if (!call_on_uniq_ || pipes->empty ()) {
            func_ (*buff_, buffsize_, arg_);
        }

        if (pipes->empty ()) {
            LIBZMQ_DELETE (pipes);
        }
    }

    //  Adjust the buffer.
    if (buffsize_ >= maxbuffsize_) {
        maxbuffsize_ = buffsize_ + 256;
        *buff_ = (unsigned char *) realloc (*buff_, maxbuffsize_);
        alloc_assert (*buff_);
    }

    //  If there are no subnodes in the trie, return.
    if (count == 0)
        return;

    //  If there's one subnode (optimisation).
    if (count == 1) {
        (*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
        if (next.node->is_redundant ()) {
            LIBZMQ_DELETE (next.node);
            count = 0;
            --live_nodes;
            zmq_assert (live_nodes == 0);
        }
        return;
    }

    //  If there are multiple subnodes.
    //
    //  New min non-null character in the node table after the removal
    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
            if (next.table[c]->is_redundant ()) {
                LIBZMQ_DELETE (next.table[c]);

                zmq_assert (live_nodes > 0);
                --live_nodes;
            } else {
                //  The node is not redundant, so it's a candidate for being
                //  the new min/max node.
                //
                //  We loop through the node array from left to right, so the
                //  first non-null, non-redundant node encountered is the new
                //  minimum index. Conversely, the last non-redundant, non-null
                //  node encountered is the new maximum index.
                if (c + min < new_min)
                    new_min = c + min;
                if (c + min > new_max)
                    new_max = c + min;
            }
        }
    }

    zmq_assert (count > 1);

    //  Free the node table if it's no longer used.
    if (live_nodes == 0) {
        free (next.table);
        next.table = NULL;
        count = 0;
    }
    //  Compact the node table if possible
    else if (live_nodes == 1) {
        //  If there's only one live node in the table we can
        //  switch to using the more compact single-node
        //  representation
        zmq_assert (new_min == new_max);
        zmq_assert (new_min >= min && new_min < min + count);
        generic_mtrie_t *node = next.table[new_min - min];
        zmq_assert (node);
        free (next.table);
        next.node = node;
        count = 1;
        min = new_min;
    } else if (new_min > min || new_max < min + count - 1) {
        zmq_assert (new_max - new_min + 1 > 1);

        generic_mtrie_t **old_table = next.table;
        zmq_assert (new_min > min || new_max < min + count - 1);
        zmq_assert (new_min >= min);
        zmq_assert (new_max <= min + count - 1);
        zmq_assert (new_max - new_min + 1 < count);

        count = new_max - new_min + 1;
        next.table =
          (generic_mtrie_t **) malloc (sizeof (generic_mtrie_t *) * count);
        alloc_assert (next.table);

        memmove (next.table, old_table + (new_min - min),
                 sizeof (generic_mtrie_t *) * count);
        free (old_table);

        min = new_min;
    }
}

template <typename T>
297 298
typename zmq::generic_mtrie_t<T>::rm_result
zmq::generic_mtrie_t<T>::rm (prefix_t prefix_, size_t size_, value_t *pipe_)
299 300 301 302 303
{
    return rm_helper (prefix_, size_, pipe_);
}

template <typename T>
304 305
typename zmq::generic_mtrie_t<T>::rm_result zmq::generic_mtrie_t<T>::rm_helper (
  prefix_t prefix_, size_t size_, value_t *pipe_)
306 307
{
    if (!size_) {
308 309 310 311 312
        if (!pipes)
            return not_found;

        typename pipes_t::size_type erased = pipes->erase (pipe_);
        if (pipes->empty ()) {
313
            zmq_assert (erased == 1);
314 315
            LIBZMQ_DELETE (pipes);
            return last_value_removed;
316
        }
317
        return (erased == 1) ? values_remain : not_found;
318 319 320 321
    }

    unsigned char c = *prefix_;
    if (!count || c < min || c >= min + count)
322
        return not_found;
323 324 325 326

    generic_mtrie_t *next_node = count == 1 ? next.node : next.table[c - min];

    if (!next_node)
327
        return not_found;
328

329
    rm_result ret = next_node->rm_helper (prefix_ + 1, size_ - 1, pipe_);
330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401

    if (next_node->is_redundant ()) {
        LIBZMQ_DELETE (next_node);
        zmq_assert (count > 0);

        if (count == 1) {
            next.node = 0;
            count = 0;
            --live_nodes;
            zmq_assert (live_nodes == 0);
        } else {
            next.table[c - min] = 0;
            zmq_assert (live_nodes > 1);
            --live_nodes;

            //  Compact the table if possible
            if (live_nodes == 1) {
                //  If there's only one live node in the table we can
                //  switch to using the more compact single-node
                //  representation
                unsigned short i;
                for (i = 0; i < count; ++i)
                    if (next.table[i])
                        break;

                zmq_assert (i < count);
                min += i;
                count = 1;
                generic_mtrie_t *oldp = next.table[i];
                free (next.table);
                next.node = oldp;
            } else if (c == min) {
                //  We can compact the table "from the left"
                unsigned short i;
                for (i = 1; i < count; ++i)
                    if (next.table[i])
                        break;

                zmq_assert (i < count);
                min += i;
                count -= i;
                generic_mtrie_t **old_table = next.table;
                next.table = (generic_mtrie_t **) malloc (
                  sizeof (generic_mtrie_t *) * count);
                alloc_assert (next.table);
                memmove (next.table, old_table + i,
                         sizeof (generic_mtrie_t *) * count);
                free (old_table);
            } else if (c == min + count - 1) {
                //  We can compact the table "from the right"
                unsigned short i;
                for (i = 1; i < count; ++i)
                    if (next.table[count - 1 - i])
                        break;

                zmq_assert (i < count);
                count -= i;
                generic_mtrie_t **old_table = next.table;
                next.table = (generic_mtrie_t **) malloc (
                  sizeof (generic_mtrie_t *) * count);
                alloc_assert (next.table);
                memmove (next.table, old_table,
                         sizeof (generic_mtrie_t *) * count);
                free (old_table);
            }
        }
    }

    return ret;
}

template <typename T>
402
template <typename Arg>
403 404
void zmq::generic_mtrie_t<T>::match (prefix_t data_,
                                     size_t size_,
405 406
                                     void (*func_) (value_t *pipe_, Arg arg_),
                                     Arg arg_)
407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453
{
    generic_mtrie_t *current = this;
    while (true) {
        //  Signal the pipes attached to this node.
        if (current->pipes) {
            for (typename pipes_t::iterator it = current->pipes->begin ();
                 it != current->pipes->end (); ++it)
                func_ (*it, arg_);
        }

        //  If we are at the end of the message, there's nothing more to match.
        if (!size_)
            break;

        //  If there are no subnodes in the trie, return.
        if (current->count == 0)
            break;

        //  If there's one subnode (optimisation).
        if (current->count == 1) {
            if (data_[0] != current->min)
                break;
            current = current->next.node;
            data_++;
            size_--;
            continue;
        }

        //  If there are multiple subnodes.
        if (data_[0] < current->min
            || data_[0] >= current->min + current->count)
            break;
        if (!current->next.table[data_[0] - current->min])
            break;
        current = current->next.table[data_[0] - current->min];
        data_++;
        size_--;
    }
}

template <typename T> bool zmq::generic_mtrie_t<T>::is_redundant () const
{
    return !pipes && live_nodes == 0;
}


#endif