https://github.com/mirek/rb_tree

Red-black tree C implementation
https://github.com/mirek/rb_tree

c-language library

Last synced: 10 months ago
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Red-black tree C implementation

• Host: GitHub
• URL: https://github.com/mirek/rb_tree
• Owner: mirek
• Created: 2012-05-14T17:52:35.000Z (over 13 years ago)
• Default Branch: master
• Last Pushed: 2018-12-03T22:25:09.000Z (about 7 years ago)
• Last Synced: 2025-03-24T03:12:18.829Z (10 months ago)
• Topics: c-language, library
• Size: 93.8 KB
• Stars: 37
• Watchers: 4
• Forks: 12
• Open Issues: 2
• Metadata Files:
  • Readme: Readme.md

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README

          
# Red-black tree C implementation

Based on Julienne Walker's  red-black tree implementation.

## Usage

First, grab the source into your project, you'll need just those two:

    wget https://raw.github.com/mirek/rb_tree/master/rb_tree.h

    wget https://raw.github.com/mirek/rb_tree/master/rb_tree.c

Let's say you want to store `struct iovec` objects (defined in `sys/uio.h`) with the following definition:

    struct iovec {

    	  void  *iov_base; // [XSI] Base address of I/O memory region

      	size_t iov_len;  // [XSI] Size of region iov_base points to

    };

You'll need to provide comparison callback for your object. Let's say you want to keep track

of the length of the iovec buffers, your callback should look similar to:

    int

    my_cmp_cb (struct rb_tree *self, struct rb_node *node_a, struct rb_node *node_b) {

        struct iovec *a = (struct iovec *) node_a->value;

        struct iovec *b = (struct iovec *) node_b->value;

        return (a->iov_len > b->iov_len) - (a->iov_len < b->iov_len);

    }

To create your red-black tree:

    struct rb_tree *tree = rb_tree_create(my_cmp_cb);

    if (tree) {

        

        // Use the tree here...

        for (int i = 0; i < 10; i++) {

            struct iovec *v = malloc(sizeof *v);

            v->iov_base = (void *) i;

            v->iov_len = i * i;

            

            // Default insert, which allocates internal rb_nodes for you.

            rb_tree_insert(tree, v);

        }

        

        // To f

        struct iovec *f = rb_tree_find(tree, & (struct iovec) { .iov_base = (void *) 7, .iov_len = 0 });

        if (r) {

            fprintf(stdout, "found iovec(.iov_base = %p, .iov_len = %zu)\n", f->iov_base, f->iov_len)

        } else {

            printf("not found\n");

        }

        // Dealloc call can take optional parameter to notify on each node

        // being deleted so you can free the node and/or your object:

        rb_tree_dealloc(tree, NULL);

    }

Above example will leak because malloc is not balanced with free.

If you want to iterate over elements (here in reverse order):

    struct rb_iter *iter = rb_iter_create();

    if (iter) {

        for (struct iovec *v = rb_iter_last(iter, tree); v; v = rb_iter_prev(iter)) {

            printf("- %p %zu\n", v->iov_base, v->iov_len);

        }

        rb_iter_dealloc(iter);

    }

## License

None (Public Domain).