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// Copyright (C) 2004-2021 Artifex Software, Inc.
//
// This file is part of MuPDF.
//
// MuPDF 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.
//
// MuPDF 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 MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
//
// Alternative licensing terms are available from the licensor.
// For commercial licensing, see <https://www.artifex.com/> or contact
// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
// CA 94129, USA, for further information.
#include "mupdf/fitz.h"
#include <string.h>
/* AA-tree */
struct fz_tree
{
char *key;
void *value;
fz_tree *left, *right;
int level;
};
static fz_tree tree_sentinel = { "", NULL, &tree_sentinel, &tree_sentinel, 0 };
static fz_tree *fz_tree_new_node(fz_context *ctx, const char *key, void *value)
{
fz_tree *node = fz_malloc_struct(ctx, fz_tree);
fz_try(ctx)
{
node->key = fz_strdup(ctx, key);
node->value = value;
node->left = node->right = &tree_sentinel;
node->level = 1;
}
fz_catch(ctx)
{
fz_free(ctx, node);
fz_rethrow(ctx);
}
return node;
}
void *fz_tree_lookup(fz_context *ctx, fz_tree *node, const char *key)
{
if (node)
{
while (node != &tree_sentinel)
{
int c = strcmp(key, node->key);
if (c == 0)
return node->value;
else if (c < 0)
node = node->left;
else
node = node->right;
}
}
return NULL;
}
static fz_tree *fz_tree_skew(fz_tree *node)
{
if (node->level != 0)
{
if (node->left->level == node->level)
{
fz_tree *save = node;
node = node->left;
save->left = node->right;
node->right = save;
}
node->right = fz_tree_skew(node->right);
}
return node;
}
static fz_tree *fz_tree_split(fz_tree *node)
{
if (node->level != 0 && node->right->right->level == node->level)
{
fz_tree *save = node;
node = node->right;
save->right = node->left;
node->left = save;
node->level++;
node->right = fz_tree_split(node->right);
}
return node;
}
fz_tree *fz_tree_insert(fz_context *ctx, fz_tree *node, const char *key, void *value)
{
if (node && node != &tree_sentinel)
{
int c = strcmp(key, node->key);
if (c < 0)
node->left = fz_tree_insert(ctx, node->left, key, value);
else
node->right = fz_tree_insert(ctx, node->right, key, value);
node = fz_tree_skew(node);
node = fz_tree_split(node);
return node;
}
else
{
return fz_tree_new_node(ctx, key, value);
}
}
void fz_drop_tree(fz_context *ctx, fz_tree *node, void (*dropfunc)(fz_context *ctx, void *value))
{
if (node)
{
if (node->left != &tree_sentinel)
fz_drop_tree(ctx, node->left, dropfunc);
if (node->right != &tree_sentinel)
fz_drop_tree(ctx, node->right, dropfunc);
fz_free(ctx, node->key);
if (dropfunc)
dropfunc(ctx, node->value);
fz_free(ctx, node);
}
}
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