#include <stdio.h>
#include <stdlib.h>
+#include "puttymem.h"
+
#include "tree234.h"
-#define mknew(typ) ( (typ *) malloc (sizeof (typ)) )
-#define sfree free
+#define mknew(typ) ( (typ *) smalloc (sizeof (typ)) )
+/* #define sfree free */
#ifdef TEST
#define LOG(x) (printf x)
n = t->root;
while (n) {
- if ( (c = t->cmp(e, n->elems[0])) < 0)
+ if ( (c = cmp(e, n->elems[0])) < 0)
n = n->kids[0];
else if (c == 0)
return n->elems[0];
- else if (n->elems[1] == NULL || (c = t->cmp(e, n->elems[1])) < 0)
+ else if (n->elems[1] == NULL || (c = cmp(e, n->elems[1])) < 0)
n = n->kids[1];
else if (c == 0)
return n->elems[1];
- else if (n->elems[2] == NULL || (c = t->cmp(e, n->elems[2])) < 0)
+ else if (n->elems[2] == NULL || (c = cmp(e, n->elems[2])) < 0)
n = n->kids[2];
else if (c == 0)
return n->elems[2];
* Delete an element e in a 2-3-4 tree. Does not free the element,
* merely removes all links to it from the tree nodes.
*/
-void *del234(tree234 *t, void *e) {
+void del234(tree234 *t, void *e) {
node234 *n;
int ei = -1;
sub->kids[1] = sub->kids[0];
sub->elems[0] = n->elems[ki-1];
sub->kids[0] = sib->kids[lastelem+1];
+ if (sub->kids[0]) sub->kids[0]->parent = sub;
n->elems[ki-1] = sib->elems[lastelem];
sib->kids[lastelem+1] = NULL;
sib->elems[lastelem] = NULL;
int j;
sub->elems[1] = n->elems[ki];
sub->kids[2] = sib->kids[0];
+ if (sub->kids[2]) sub->kids[2]->parent = sub;
n->elems[ki] = sib->elems[0];
sib->kids[0] = sib->kids[1];
for (j = 0; j < 2 && sib->elems[j+1]; j++) {
sub->kids[2] = sub->kids[0];
sub->elems[1] = n->elems[ki];
sub->kids[1] = sib->kids[1];
+ if (sub->kids[1]) sub->kids[1]->parent = sub;
sub->elems[0] = sib->elems[0];
sub->kids[0] = sib->kids[0];
+ if (sub->kids[0]) sub->kids[0]->parent = sub;
sfree(sib);
}
n->kids[j] = NULL;
if (j < 3) n->elems[j] = NULL;
- LOG((" case 3b\n"));
+ LOG((" case 3b ki=%d\n", ki));
if (!n->elems[0]) {
/*
*/
int i;
LOG((" case 1\n"));
- for (i = ei; i < 3 && n->elems[i+1]; i++)
+ for (i = ei; i < 2 && n->elems[i+1]; i++)
n->elems[i] = n->elems[i+1];
n->elems[i] = NULL;
return; /* finished! */
LOG((" case 2c\n"));
a->elems[1] = n->elems[ei];
a->kids[2] = b->kids[0];
+ if (a->kids[2]) a->kids[2]->parent = a;
a->elems[2] = b->elems[0];
a->kids[3] = b->kids[1];
+ if (a->kids[3]) a->kids[3]->parent = a;
sfree(b);
/*
* That's built the big node in a, and destroyed b. Now
}
n->elems[j] = NULL;
n->kids[j+1] = NULL;
+ /*
+ * It's possible, in this case, that we've just removed
+ * the only element in the root of the tree. If so,
+ * shift the root.
+ */
+ if (n->elems[0] == NULL) {
+ LOG((" shifting root!\n"));
+ t->root = a;
+ a->parent = NULL;
+ sfree(n);
+ }
/*
* Now go round the deletion process again, with n
* pointing at the new big node and e still the same.
return n->elems[0];
}
- if (pos == 0 && n->elems[1]) {
- e->posn = 1;
- return n->elems[1];
+ if (pos < 2 && n->elems[pos+1]) {
+ e->posn = pos+1;
+ return n->elems[e->posn];
}
do {
#ifdef TEST
-int pnode(node234 *n, int level) {
- printf("%*s%p\n", level*4, "", n);
- if (n->kids[0]) pnode(n->kids[0], level+1);
- if (n->elems[0]) printf("%*s\"%s\"\n", level*4+4, "", n->elems[0]);
- if (n->kids[1]) pnode(n->kids[1], level+1);
- if (n->elems[1]) printf("%*s\"%s\"\n", level*4+4, "", n->elems[1]);
- if (n->kids[2]) pnode(n->kids[2], level+1);
- if (n->elems[2]) printf("%*s\"%s\"\n", level*4+4, "", n->elems[2]);
- if (n->kids[3]) pnode(n->kids[3], level+1);
+/*
+ * Test code for the 2-3-4 tree. This code maintains an alternative
+ * representation of the data in the tree, in an array (using the
+ * obvious and slow insert and delete functions). After each tree
+ * operation, the verify() function is called, which ensures all
+ * the tree properties are preserved (node->child->parent always
+ * equals node; number of kids == 0 or number of elements + 1;
+ * ordering property between elements of a node and elements of its
+ * children is preserved; tree has the same depth everywhere; every
+ * node has at least one element) and also ensures the list
+ * represented by the tree is the same list it should be. (This
+ * last check also verifies the ordering properties, because the
+ * `same list it should be' is by definition correctly ordered. It
+ * also ensures all nodes are distinct, because the enum functions
+ * would get caught in a loop if not.)
+ */
+
+#include <stdarg.h>
+
+/*
+ * Error reporting function.
+ */
+void error(char *fmt, ...) {
+ va_list ap;
+ printf("ERROR: ");
+ va_start(ap, fmt);
+ vfprintf(stdout, fmt, ap);
+ va_end(ap);
+ printf("\n");
}
-int ptree(tree234 *t) {
- if (t->root)
- pnode(t->root, 0);
- else
- printf("empty tree\n");
+
+/* The array representation of the data. */
+void **array;
+int arraylen, arraysize;
+cmpfn234 cmp;
+
+/* The tree representation of the same data. */
+tree234 *tree;
+
+typedef struct {
+ int treedepth;
+ int elemcount;
+} chkctx;
+
+void chknode(chkctx *ctx, int level, node234 *node,
+ void *lowbound, void *highbound) {
+ int nkids, nelems;
+ int i;
+
+ /* Count the non-NULL kids. */
+ for (nkids = 0; nkids < 4 && node->kids[nkids]; nkids++);
+ /* Ensure no kids beyond the first NULL are non-NULL. */
+ for (i = nkids; i < 4; i++)
+ if (node->kids[i]) {
+ error("node %p: nkids=%d but kids[%d] non-NULL",
+ node, nkids, i);
+ }
+
+ /* Count the non-NULL elements. */
+ for (nelems = 0; nelems < 3 && node->elems[nelems]; nelems++);
+ /* Ensure no elements beyond the first NULL are non-NULL. */
+ for (i = nelems; i < 3; i++)
+ if (node->elems[i]) {
+ error("node %p: nelems=%d but elems[%d] non-NULL",
+ node, nelems, i);
+ }
+
+ if (nkids == 0) {
+ /*
+ * If nkids==0, this is a leaf node; verify that the tree
+ * depth is the same everywhere.
+ */
+ if (ctx->treedepth < 0)
+ ctx->treedepth = level; /* we didn't know the depth yet */
+ else if (ctx->treedepth != level)
+ error("node %p: leaf at depth %d, previously seen depth %d",
+ node, level, ctx->treedepth);
+ } else {
+ /*
+ * If nkids != 0, then it should be nelems+1, unless nelems
+ * is 0 in which case nkids should also be 0 (and so we
+ * shouldn't be in this condition at all).
+ */
+ int shouldkids = (nelems ? nelems+1 : 0);
+ if (nkids != shouldkids) {
+ error("node %p: %d elems should mean %d kids but has %d",
+ node, nelems, shouldkids, nkids);
+ }
+ }
+
+ /*
+ * nelems should be at least 1.
+ */
+ if (nelems == 0) {
+ error("node %p: no elems", node, nkids);
+ }
+
+ /*
+ * Add nelems to the running element count of the whole tree
+ * (to ensure the enum234 routines see them all).
+ */
+ ctx->elemcount += nelems;
+
+ /*
+ * Check ordering property: all elements should be strictly >
+ * lowbound, strictly < highbound, and strictly < each other in
+ * sequence. (lowbound and highbound are NULL at edges of tree
+ * - both NULL at root node - and NULL is considered to be <
+ * everything and > everything. IYSWIM.)
+ */
+ for (i = -1; i < nelems; i++) {
+ void *lower = (i == -1 ? lowbound : node->elems[i]);
+ void *higher = (i+1 == nelems ? highbound : node->elems[i+1]);
+ if (lower && higher && cmp(lower, higher) >= 0) {
+ error("node %p: kid comparison [%d=%s,%d=%s] failed",
+ node, i, lower, i+1, higher);
+ }
+ }
+
+ /*
+ * Check parent pointers: all non-NULL kids should have a
+ * parent pointer coming back to this node.
+ */
+ for (i = 0; i < nkids; i++)
+ if (node->kids[i]->parent != node) {
+ error("node %p kid %d: parent ptr is %p not %p",
+ node, i, node->kids[i]->parent, node);
+ }
+
+
+ /*
+ * Now (finally!) recurse into subtrees.
+ */
+ for (i = 0; i < nkids; i++) {
+ void *lower = (i == 0 ? lowbound : node->elems[i-1]);
+ void *higher = (i >= nelems ? highbound : node->elems[i]);
+ chknode(ctx, level+1, node->kids[i], lower, higher);
+ }
}
-int cmp(void *av, void *bv) {
- char *a = (char *)av;
- char *b = (char *)bv;
+void verify(void) {
+ chkctx ctx;
+ enum234 e;
+ int i;
+ void *p;
+
+ ctx.treedepth = -1; /* depth unknown yet */
+ ctx.elemcount = 0; /* no elements seen yet */
+ /*
+ * Verify validity of tree properties.
+ */
+ if (tree->root)
+ chknode(&ctx, 0, tree->root, NULL, NULL);
+ printf("tree depth: %d\n", ctx.treedepth);
+ /*
+ * Enumerate the tree and ensure it matches up to the array.
+ */
+ for (i = 0, p = first234(tree, &e);
+ p;
+ i++, p = next234(&e)) {
+ if (i >= arraylen)
+ error("tree contains more than %d elements", arraylen);
+ if (array[i] != p)
+ error("enum at position %d: array says %s, tree says %s",
+ i, array[i], p);
+ }
+ if (i != ctx.elemcount) {
+ error("tree really contains %d elements, enum gave %d",
+ i, ctx.elemcount);
+ }
+ if (i < arraylen) {
+ error("enum gave only %d elements, array has %d", i, arraylen);
+ }
+}
+
+void addtest(void *elem) {
+ int i, j;
+ void *retval, *realret;
+
+ if (arraysize < arraylen+1) {
+ arraysize = arraylen+1+256;
+ array = (array == NULL ? smalloc(arraysize*sizeof(*array)) :
+ srealloc(array, arraysize*sizeof(*array)));
+ }
+
+ i = 0;
+ while (i < arraylen && cmp(elem, array[i]) > 0)
+ i++;
+ /* now i points to the first element >= elem */
+ if (i < arraylen && !cmp(elem, array[i]))
+ retval = array[i]; /* expect that returned not elem */
+ else {
+ retval = elem; /* expect elem returned (success) */
+ for (j = arraylen; j > i; j--)
+ array[j] = array[j-1];
+ array[i] = elem; /* add elem to array */
+ arraylen++;
+ }
+
+ realret = add234(tree, elem);
+ if (realret != retval) {
+ error("add: retval was %p expected %p", realret, retval);
+ }
+
+ verify();
+}
+
+void deltest(void *elem) {
+ int i;
+
+ i = 0;
+ while (i < arraylen && cmp(elem, array[i]) > 0)
+ i++;
+ /* now i points to the first element >= elem */
+ if (i >= arraylen || cmp(elem, array[i]) != 0)
+ return; /* don't do it! */
+ else {
+ while (i < arraylen-1) {
+ array[i] = array[i+1];
+ i++;
+ }
+ arraylen--; /* delete elem from array */
+ }
+
+ del234(tree, elem);
+
+ verify();
+}
+
+/* A sample data set and test utility. Designed for pseudo-randomness,
+ * and yet repeatability. */
+
+/*
+ * This random number generator uses the `portable implementation'
+ * given in ANSI C99 draft N869. It assumes `unsigned' is 32 bits;
+ * change it if not.
+ */
+int randomnumber(unsigned *seed) {
+ *seed *= 1103515245;
+ *seed += 12345;
+ return ((*seed) / 65536) % 32768;
+}
+
+int mycmp(void *av, void *bv) {
+ char const *a = (char const *)av;
+ char const *b = (char const *)bv;
return strcmp(a, b);
}
+#define lenof(x) ( sizeof((x)) / sizeof(*(x)) )
+
+char *strings[] = {
+ "a", "ab", "absque", "coram", "de",
+ "palam", "clam", "cum", "ex", "e",
+ "sine", "tenus", "pro", "prae",
+ "banana", "carrot", "cabbage", "broccoli", "onion", "zebra",
+ "penguin", "blancmange", "pangolin", "whale", "hedgehog",
+ "giraffe", "peanut", "bungee", "foo", "bar", "baz", "quux",
+ "murfl", "spoo", "breen", "flarn", "octothorpe",
+ "snail", "tiger", "elephant", "octopus", "warthog", "armadillo",
+ "aardvark", "wyvern", "dragon", "elf", "dwarf", "orc", "goblin",
+ "pixie", "basilisk", "warg", "ape", "lizard", "newt", "shopkeeper",
+ "wand", "ring", "amulet"
+};
+
+#define NSTR lenof(strings)
+
int main(void) {
- tree234 *t = newtree234(cmp);
-
- add234(t, "Richard");
- add234(t, "Of");
- add234(t, "York");
- add234(t, "Gave");
- add234(t, "Battle");
- add234(t, "In");
- add234(t, "Vain");
- add234(t, "Rabbits");
- add234(t, "On");
- add234(t, "Your");
- add234(t, "Garden");
- add234(t, "Bring");
- add234(t, "Invisible");
- add234(t, "Vegetables");
-
- ptree(t);
- del234(t, find234(t, "Richard", NULL));
- ptree(t);
- del234(t, find234(t, "Of", NULL));
- ptree(t);
- del234(t, find234(t, "York", NULL));
- ptree(t);
- del234(t, find234(t, "Gave", NULL));
- ptree(t);
- del234(t, find234(t, "Battle", NULL));
- ptree(t);
- del234(t, find234(t, "In", NULL));
- ptree(t);
- del234(t, find234(t, "Vain", NULL));
- ptree(t);
- del234(t, find234(t, "Rabbits", NULL));
- ptree(t);
- del234(t, find234(t, "On", NULL));
- ptree(t);
- del234(t, find234(t, "Your", NULL));
- ptree(t);
- del234(t, find234(t, "Garden", NULL));
- ptree(t);
- del234(t, find234(t, "Bring", NULL));
- ptree(t);
- del234(t, find234(t, "Invisible", NULL));
- ptree(t);
- del234(t, find234(t, "Vegetables", NULL));
- ptree(t);
+ int in[NSTR];
+ int i, j;
+ unsigned seed = 0;
+
+ for (i = 0; i < NSTR; i++) in[i] = 0;
+ array = NULL;
+ arraylen = arraysize = 0;
+ tree = newtree234(mycmp);
+ cmp = mycmp;
+
+ verify();
+ for (i = 0; i < 10000; i++) {
+ j = randomnumber(&seed);
+ j %= NSTR;
+ printf("trial: %d\n", i);
+ if (in[j]) {
+ printf("deleting %s (%d)\n", strings[j], j);
+ deltest(strings[j]);
+ in[j] = 0;
+ } else {
+ printf("adding %s (%d)\n", strings[j], j);
+ addtest(strings[j]);
+ in[j] = 1;
+ }
+ }
+
+ while (arraylen > 0) {
+ j = randomnumber(&seed);
+ j %= arraylen;
+ deltest(array[j]);
+ }
+
+ return 0;
}
+
#endif
projects / u / mdw / putty / blobdiff