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/*
* token.c : routines for doing diffs
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*/
#include <apr.h>
#include <apr_pools.h>
#include <apr_general.h>
#include "svn_error.h"
#include "svn_diff.h"
#include "svn_types.h"
#include "diff.h"
/*
* Prime number to use as the size of the hash table. This number was
* not selected by testing of any kind and may need tweaking.
*/
#define SVN_DIFF__HASH_SIZE 127
struct svn_diff__node_t
{
svn_diff__node_t *parent;
svn_diff__node_t *left;
svn_diff__node_t *right;
apr_uint32_t hash;
svn_diff__token_index_t index;
void *token;
};
struct svn_diff__tree_t
{
svn_diff__node_t *root[SVN_DIFF__HASH_SIZE];
apr_pool_t *pool;
svn_diff__token_index_t node_count;
};
/*
* Returns number of tokens in a tree
*/
svn_diff__token_index_t
svn_diff__get_node_count(svn_diff__tree_t *tree)
{
return tree->node_count;
}
/*
* Support functions to build a tree of token positions
*/
void
svn_diff__tree_create(svn_diff__tree_t **tree, apr_pool_t *pool)
{
*tree = apr_pcalloc(pool, sizeof(**tree));
(*tree)->pool = pool;
(*tree)->node_count = 0;
}
static svn_error_t *
tree_insert_token(svn_diff__node_t **node, svn_diff__tree_t *tree,
void *diff_baton,
const svn_diff_fns2_t *vtable,
apr_uint32_t hash, void *token)
{
svn_diff__node_t *new_node;
svn_diff__node_t **node_ref;
svn_diff__node_t *parent;
int rv;
SVN_ERR_ASSERT(token);
parent = NULL;
node_ref = &tree->root[hash % SVN_DIFF__HASH_SIZE];
while (*node_ref != NULL)
{
parent = *node_ref;
rv = hash - parent->hash;
if (!rv)
SVN_ERR(vtable->token_compare(diff_baton, parent->token, token, &rv));
if (rv == 0)
{
/* Discard the previous token. This helps in cases where
* only recently read tokens are still in memory.
*/
if (vtable->token_discard != NULL)
vtable->token_discard(diff_baton, parent->token);
parent->token = token;
*node = parent;
return SVN_NO_ERROR;
}
else if (rv > 0)
{
node_ref = &parent->left;
}
else
{
node_ref = &parent->right;
}
}
/* Create a new node */
new_node = apr_palloc(tree->pool, sizeof(*new_node));
new_node->parent = parent;
new_node->left = NULL;
new_node->right = NULL;
new_node->hash = hash;
new_node->token = token;
new_node->index = tree->node_count++;
*node = *node_ref = new_node;
return SVN_NO_ERROR;
}
/*
* Get all tokens from a datasource. Return the
* last item in the (circular) list.
*/
svn_error_t *
svn_diff__get_tokens(svn_diff__position_t **position_list,
svn_diff__tree_t *tree,
void *diff_baton,
const svn_diff_fns2_t *vtable,
svn_diff_datasource_e datasource,
apr_off_t prefix_lines,
apr_pool_t *pool)
{
svn_diff__position_t *start_position;
svn_diff__position_t *position = NULL;
svn_diff__position_t **position_ref;
svn_diff__node_t *node;
void *token;
apr_off_t offset;
apr_uint32_t hash;
*position_list = NULL;
position_ref = &start_position;
offset = prefix_lines;
hash = 0; /* The callback fn doesn't need to touch it per se */
while (1)
{
SVN_ERR(vtable->datasource_get_next_token(&hash, &token,
diff_baton, datasource));
if (token == NULL)
break;
offset++;
SVN_ERR(tree_insert_token(&node, tree, diff_baton, vtable, hash, token));
/* Create a new position */
position = apr_palloc(pool, sizeof(*position));
position->next = NULL;
position->token_index = node->index;
position->offset = offset;
*position_ref = position;
position_ref = &position->next;
}
*position_ref = start_position;
SVN_ERR(vtable->datasource_close(diff_baton, datasource));
*position_list = position;
return SVN_NO_ERROR;
}
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