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Implementation of Radix tree for NAT

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This commit is contained in:
Michal Zima 2010-02-22 14:46:18 +01:00
parent ecefe998eb
commit 3d8d8ace2a
2 changed files with 237 additions and 0 deletions
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198
src/radixtree.c Normal file
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/*
* WrapSix
* Copyright (C) 2008-2010 Michal Zima <xhire@mujmalysvet.cz>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
radixtree_t *radixtree_create()
{
radixtree_t *radixtree;
if ((radixtree = (radixtree_t *) malloc(sizeof(radixtree_t))) == NULL) {
fprintf(stderr, "[Error] Lack of free memory\n");
return NULL;
}
memset(radixtree, 0, sizeof(radixtree_t));
radixtree->count = 0;
return radixtree;
}
void radixtree_destroy(radixtree_t *t, unsigned char depth)
{
unsigned char i;
for (i = 0; i < ARRAY_SIZE; i++) {
if (depth != 1 && t->array[i] != NULL) {
radixtree_destroy(t->array[i], depth - 1);
} else if (depth == 1) {
free(t->array[i]);
}
}
free(t);
}
void radixtree_insert(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *search_data, void *data)
{
radixtree_t *tmp;
unsigned char i, chunk_count;
unsigned char *chunks;
chunks = chunker(search_data, &chunk_count);
tmp = root;
tmp->count++;
for (i = 0; i < chunk_count; i++) {
unsigned char id;
id = chunk[i];
if (i == chunk_count - 1) {
tmp->array[id] = data;
return;
}
if (tmp->array[id] == NULL) {
tmp->array[id] = radixtree_create();
}
tmp = tmp->array[id];
tmp->count++;
}
}
void radixtree_delete(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *data)
{
radixtree_t *tmp,
*next;
unsigned char i, chunk_count;
unsigned char *chunks;
chunks = chunker(data, &chunk_count);
tmp = root;
tmp->count--;
for (i = 0; i < chunk_count; i++) {
unsigned char id;
id = chunk[i];
/* already deleted? may cause data inconsistency! */
if (tmp->array[id] == NULL) {
return;
}
if (i == chunk_count - 1) {
if (tmp->count == 0) {
free(tmp);
} else {
tmp->array[id] = NULL;
}
/**
* now you *have to* call free on data too
* but probably not here...
**/
return;
}
next = tmp->array[id];
/* if it is the last entry in this tree branch */
if (next->count == 1) {
tmp->array[id] = NULL;
}
if (i != 0 && tmp->count == 0) {
free(tmp);
}
tmp = next;
tmp->count--;
}
}
radixtree_t *radixtree_lookup(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *data)
{
radixtree_t *tmp;
unsigned char i, chunk_count;
unsigned char *chunks;
chunks = chunker(data, &chunk_count);
tmp = root;
for (i = 0; i < chunk_count; i++) {
unsigned char id;
id = chunk[i];
if (i == chunk_count - 1) {
return tmp->array[id];
}
if (tmp->array[id] == NULL) {
return NULL;
}
tmp = tmp->array[id];
}
}
unsigned char *radixtree_outgoing_chunker(void *data, unsigned char *count)
{
short i;
unsigned char counter;
counter = 198 / 6;
memcpy(count, &counter, sizeof(unsigned char));
unsigned char chunks[counter];
/* 128 + 16 + 32 + 16 - 6 = 192 */
for (i = 192, counter = 0; i >= 0; i -= 6, counter++) {
chunks[counter] = (*data >> i) & 63; /* 63 == 0011 1111 */
}
return chunks;
}
unsigned char *radixtree_incoming_chunker(void *data, unsigned char *count)
{
short i;
unsigned char counter;
counter = 72 / 6;
memcpy(count, &counter, sizeof(unsigned char));
unsigned char chunks[counter];
/* 32 + 16 + 16 + 8 - 6 = 66 */
for (i = 66, counter = 0; i >= 0; i -= 6, counter++) {
chunks[counter] = (*data >> i) & 63; /* 63 == 0011 1111 */
}
return chunks;
}

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src/radixtree.h Normal file
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/*
* WrapSix
* Copyright (C) 2008-2010 Michal Zima <xhire@mujmalysvet.cz>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define CHUNK_SIZE 6
#define ARRAY_SIZE 64 /* 2 ^ CHUNK_SIZE */
typedef struct radixtree {
void *array[ARRAY_SIZE];
unsigned int count;
} radixtree_t;
radixtree_t *radixtree_create();
void radixtree_destroy(radixtree_t *t, unsigned char depth);
void radixtree_insert(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *search_data, void *data);
void radixtree_delete(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *data);
radixtree_t *radixtree_lookup(radixtree_t *root,
unsigned char *(chunker)(void *data, unsigned char *count),
void *data);
unsigned char *radixtree_outgoing_chunker(void *data, unsigned char *count);
unsigned char *radixtree_incoming_chunker(void *data, unsigned char *count);