1.1 --- a/CMakeLists.txt	Thu Oct 04 23:07:48 2012 -0500
     1.2 +++ b/CMakeLists.txt	Tue Oct 16 19:57:23 2012 -0500
     1.3 @@ -118,3 +118,8 @@
     1.4    ${trie_sedgewick_SRCS}
     1.5    )
     1.6  
     1.7 +set (btree_mem_SRCS src/btree_mem.h src/btree_mem.c)
     1.8 +add_executable (btree_mem_test
     1.9 +  src/btree_mem_test.c
    1.10 +  ${btree_mem_SRCS}
    1.11 +  )
    1.12 \ No newline at end of file

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/src/btree_mem.c	Tue Oct 16 19:57:23 2012 -0500
     2.3 @@ -0,0 +1,220 @@
     2.4 +#include <stdio.h>
     2.5 +
     2.6 +#include <stdlib.h>
     2.7 +#include <stdbool.h>
     2.8 +
     2.9 +#include "btree_mem.h"
    2.10 +
    2.11 +// In btree_mem_node, child[0].keys <= key[0] < child[1].keys <= key[1] < child[2].keys ...
    2.12 +struct btree_mem_node
    2.13 +   {
    2.14 +   int nkeys;
    2.15 +   void ** key;
    2.16 +   void ** data;
    2.17 +   struct btree_mem_node ** child;
    2.18 +   bool leaf;
    2.19 +   };
    2.20 +
    2.21 +struct btree_mem_node * btree_mem_node_new    (struct btree_mem * bt);
    2.22 +void                    btree_mem_node_delete (struct btree_mem_node * node);
    2.23 +
    2.24 +struct btree_mem_node * btree_mem_node_find   (struct btree_mem * bt, struct btree_mem_node * node, void * key, int * i);
    2.25 +
    2.26 +void *                  btree_mem_node_insert (struct btree_mem * bt, struct btree_mem_node * node, void * key, void * data);
    2.27 +struct btree_mem_node * btree_mem_split_child (struct btree_mem * bt, struct btree_mem_node * x, int i, struct btree_mem_node * y);
    2.28 +
    2.29 +////////////////////////////////////////////////////////////////////////////////
    2.30 +struct btree_mem *
    2.31 +btree_mem_new(int min_degree, int (*cmp)(void *, void *))
    2.32 +   {
    2.33 +   struct btree_mem * bt = malloc(sizeof(struct btree_mem));
    2.34 +   if (NULL == bt)
    2.35 +      return NULL;
    2.36 +
    2.37 +   bt->mindeg = min_degree;
    2.38 +   bt->cmp = cmp;
    2.39 +
    2.40 +   bt->root = btree_mem_node_new(bt);
    2.41 +   if (NULL == bt->root)
    2.42 +      {
    2.43 +      free(bt);
    2.44 +      return NULL;
    2.45 +      }
    2.46 +
    2.47 +   return bt;
    2.48 +   }
    2.49 +
    2.50 +////////////////////////////////////////////////////////////////////////////////
    2.51 +// IMPORTANT NOTE: All keys and data must be removed first or else memory
    2.52 +// will leak.
    2.53 +void
    2.54 +btree_mem_delete(struct btree_mem * bt)
    2.55 +   {
    2.56 +   // TODO: walk down the tree and delete all nodes.
    2.57 +   free(bt);
    2.58 +   }
    2.59 +
    2.60 +////////////////////////////////////////////////////////////////////////////////
    2.61 +struct btree_mem_node *
    2.62 +btree_mem_node_new(struct btree_mem * bt)
    2.63 +   {
    2.64 +   struct btree_mem_node * node = malloc(sizeof(struct btree_mem_node));
    2.65 +   if (NULL == node)
    2.66 +      return NULL;
    2.67 +
    2.68 +   int maxchild = 2*bt->mindeg;
    2.69 +
    2.70 +   node->key  = malloc( (maxchild - 1) * sizeof(void *));
    2.71 +   if (NULL == node->key)
    2.72 +      {
    2.73 +      free(node);
    2.74 +      return NULL;
    2.75 +      }
    2.76 +
    2.77 +   node->data = malloc( (maxchild - 1) * sizeof(void *));
    2.78 +   if (NULL == node->data)
    2.79 +      {
    2.80 +      free(node->key);
    2.81 +      free(node);
    2.82 +      return NULL;
    2.83 +      }
    2.84 +
    2.85 +   node->child = malloc( maxchild * sizeof(struct btree_mem_node *));
    2.86 +   if (NULL == node->data)
    2.87 +      {
    2.88 +      free(node->data);
    2.89 +      free(node->key);
    2.90 +      free(node);
    2.91 +      return NULL;
    2.92 +      }
    2.93 +
    2.94 +   node->nkeys = 0;
    2.95 +   node->leaf = false;
    2.96 +
    2.97 +   return node;
    2.98 +   }
    2.99 +
   2.100 +////////////////////////////////////////////////////////////////////////////////
   2.101 +// IMPORTANT NOTE: All keys and data must be removed first or else memory
   2.102 +// will leak.
   2.103 +void
   2.104 +btree_mem_node_delete(struct btree_mem_node * node)
   2.105 +   {
   2.106 +   free(node->child);
   2.107 +   free(node->data);
   2.108 +   free(node->key);
   2.109 +   free(node);
   2.110 +   }
   2.111 +
   2.112 +////////////////////////////////////////////////////////////////////////////////
   2.113 +void *
   2.114 +btree_mem_find(struct btree_mem * bt, void * key)
   2.115 +   {
   2.116 +   int i;
   2.117 +   struct btree_mem_node * node = btree_mem_node_find(bt, bt->root, key, &i);
   2.118 +   if (NULL == node)
   2.119 +      return NULL;
   2.120 +   return node->data[i];
   2.121 +   }
   2.122 +
   2.123 +////////////////////////////////////////////////////////////////////////////////
   2.124 +struct btree_mem_node *
   2.125 +btree_mem_node_find(struct btree_mem * bt, struct btree_mem_node * node, void * key, int * i)
   2.126 +   {
   2.127 +   *i = 0;
   2.128 +   while (( *i < node->nkeys) && (bt->cmp(key, node->key[*i]) > 0) )
   2.129 +      (*i)++;
   2.130 +   if ( (*i < node->nkeys) && (bt->cmp(key, node->key[*i]) == 0) )
   2.131 +      return node;
   2.132 +   if (node->leaf)
   2.133 +      return NULL;
   2.134 +   else
   2.135 +      return btree_mem_node_find(bt, node->child[*i], key, i);
   2.136 +   }
   2.137 +
   2.138 +////////////////////////////////////////////////////////////////////////////////
   2.139 +void *
   2.140 +btree_mem_insert(struct btree_mem * bt, void * key, void * data)
   2.141 +   {
   2.142 +   return btree_mem_node_insert(bt, bt->root, key, data);
   2.143 +   }
   2.144 +
   2.145 +////////////////////////////////////////////////////////////////////////////////
   2.146 +void *
   2.147 +btree_mem_node_insert(struct btree_mem * bt, struct btree_mem_node * node, void * key, void * data)
   2.148 +   {
   2.149 +   struct btree_node * r = bt->root;
   2.150 +   if ((2 * bt->mindeg - 1) == node->nkeys)
   2.151 +      {
   2.152 +      struct btree_node * s = btree_mem_node_new(bt);
   2.153 +      if (NULL == s)
   2.154 +	 return NULL;
   2.155 +      bt->root = s;
   2.156 +      s->child[0] = r;
   2.157 +      btree_mem_split_child(bt, s, 1, r);
   2.158 +      r = s;
   2.159 +      }
   2.160 +   return btree_mem_node_insert(bt, s, key, data);
   2.161 +   }
   2.162 +
   2.163 +////////////////////////////////////////////////////////////////////////////////
   2.164 +// x - a non-full node
   2.165 +// y - a full node that is a child of x
   2.166 +// i - The index of y in x's child list.  That is x->child[i] == y.
   2.167 +//
   2.168 +// Split y in half, adding the newly created node z as a new child of x.
   2.169 +// z will be placed after y in the child list.
   2.170 +
   2.171 +struct btree_mem_node *
   2.172 +btree_mem_split_child(struct btree_mem * bt, struct btree_mem_node * x, int i, struct btree_mem_node * y)
   2.173 +   {
   2.174 +
   2.175 +   // Allocate new node.
   2.176 +   struct btree_mem_node * z = btree_mem_node_new(bt);
   2.177 +   if (NULL == z)
   2.178 +      return NULL;
   2.179 +
   2.180 +   // Load z with the second half of y's data;
   2.181 +   z->leaf = y->leaf;
   2.182 +   z->nkeys = bt->mindeg - 1;
   2.183 +   for (int j = 0; j < bt->mindeg - 1; j++)
   2.184 +      {
   2.185 +      z->key[j] = y->key[j + bt->mindeg];
   2.186 +      z->data[j] = y->data[j + bt->mindeg];
   2.187 +      }
   2.188 +   if (! y->leaf)
   2.189 +      {
   2.190 +      for (int j = 0; j < bt->mindeg)
   2.191 +	 z->child[j] = y->child[j + bt->mindeg];
   2.192 +      }
   2.193 +
   2.194 +   // Update y's nkeys.  We don't bother NULLing out the now unused key and data pointers.
   2.195 +   y->nkeys = bt->mindeg - 1;
   2.196 +
   2.197 +   // Make a hole in x's child list for the new node z.
   2.198 +   for (int j = x->nkeys; j > i; j--)
   2.199 +      x->child[j+1] = x->child[j];
   2.200 +   x->child[i] = z;
   2.201 +
   2.202 +   // Make a hole in x's key list for the new node z.
   2.203 +   for (int j = x->nkeys - 1; j > i-1; j--)
   2.204 +      {
   2.205 +      x->key[j+1] = x->key[j];
   2.206 +      x->data[j+1] = x->data[j];
   2.207 +      }
   2.208 +   x->key[i] = y->key[bt->mindeg-1];
   2.209 +   x->data[i] = y->data[bt->mindeg-1];
   2.210 +
   2.211 +
   2.212 +   x->nkeys += 1;
   2.213 +
   2.214 +   return z;
   2.215 +   }
   2.216 +
   2.217 +////////////////////////////////////////////////////////////////////////////////
   2.218 +void *
   2.219 +btree_mem_remove(struct btree_mem * bt, void * key)
   2.220 +   {
   2.221 +   
   2.222 +   }
   2.223 +

     3.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     3.2 +++ b/src/btree_mem.h	Tue Oct 16 19:57:23 2012 -0500
     3.3 @@ -0,0 +1,21 @@
     3.4 +#ifndef BTREE_MEM_H_
     3.5 +#define BTREE_MEM_H_
     3.6 +
     3.7 +
     3.8 +struct btree_mem_node;
     3.9 +
    3.10 +struct btree_mem
    3.11 +   {
    3.12 +   int mindeg;
    3.13 +   struct btree_mem_node * root;
    3.14 +   int (*cmp)(void *, void *);
    3.15 +   };
    3.16 +
    3.17 +struct btree_mem * btree_mem_new(int min_degree, int (*cmp)(void *, void *));
    3.18 +void btree_mem_delete(struct btree_mem * bt);
    3.19 +
    3.20 +void * btree_mem_insert(struct btree_mem * bt, void * key, void * data);
    3.21 +void * btree_mem_find(struct btree_mem * bt, void * key);
    3.22 +void * btree_mem_remove(struct btree_mem * bt, void * key);
    3.23 +
    3.24 +#endif

     4.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     4.2 +++ b/src/btree_mem_test.c	Tue Oct 16 19:57:23 2012 -0500
     4.3 @@ -0,0 +1,23 @@
     4.4 +#include <stdio.h>
     4.5 +#include <stdlib.h>
     4.6 +#include <string.h>
     4.7 +
     4.8 +#include "btree_mem.h"
     4.9 +
    4.10 +int
    4.11 +cmp(void * a, void * b)
    4.12 +   {
    4.13 +   return strcmp(a, b);
    4.14 +   }
    4.15 +
    4.16 +int
    4.17 +main(int argc, char ** argv)
    4.18 +   {
    4.19 +   struct btree_mem * bt = btree_mem_new(2, cmp);
    4.20 +   if (NULL == bt)
    4.21 +      {
    4.22 +      fprintf(stderr, "Unable to create new btree_mem\n");
    4.23 +      exit(EXIT_FAILURE);
    4.24 +      }
    4.25 +   exit(EXIT_SUCCESS);
    4.26 +   }