initial hash object with testing framework

hash.c

@@ -0,0 +1,259 @@
+/* 
+ * a fixed-sized hash
+ *
+# Copyright (C) 2022  Yves Rutschle
+# 
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later
+# version.
+# 
+# This program 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 General Public License for more
+# details.
+# 
+# The full text for the General Public License is here:
+# http://www.gnu.org/licenses/gpl.html
+#
+# */
+
+
+/*  * The hash is open-addressing, linear search, robin-hood insertion, with 
+ * backward shift deletion and moving floor.
+ * https://codecapsule.com/2013/11/11/robin-hood-hashing/
+ * https://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/
+ * This means items are reordered upon insertion and deletion, and the hash
+ * is well-ordered at all times with no tombstones.
+ *
+ * Items that 'wrap' around push the 'floor' up. Searching for low items will
+ * therefore start from the floor up.
+ *
+ * Each pointer is either:
+ * - to a connection struct
+ * - FREE (NULL) if not allocated
+ *
+ * */
+
+#include <stdlib.h>
+#include <stddef.h>
+
+#include "gap.h"
+#include "hash.h"
+
+static const int h_keylen = 5; /* How many bits in the hash key? (hash is 2^h_keylen big) */
+static const int hash_size = (1 << h_keylen); /* 8 => 256 */
+static void* const FREE = NULL;
+
+struct hash {
+    int item_cnt;       /* Number of items in the hash */
+    int floor;          /* Where is the highest key. Or the lowest insert point */
+    gap_array* data;
+
+    hash_make_key_fn hash_make_key;
+    hash_cmp_item_fn cmp_item;
+};
+
+typedef struct hash hash;
+
+
+hash* hash_init(hash_make_key_fn make_key, hash_cmp_item_fn cmp_item)
+{
+    hash* h = malloc(sizeof(*h));
+    if (!h) return NULL;
+
+    h->item_cnt = 0;
+    h->floor = 0;
+    h->data = gap_init(hash_size);
+    h->hash_make_key = make_key;
+    h->cmp_item = cmp_item;
+
+    return h;
+}
+
+/* Return the index following i in h */
+static int hash_next_index(hash* h, int i)
+{
+    return (i + 1) % hash_size;
+}
+
+/* Returns the index in h of specified address, -1 if not found 
+ * item is an item object that must return the target wanted index and for
+ * which comparison with the searched object will succeed.
+ * */
+int hash_find_index(hash* h, hash_item item)
+{
+    hash_item cnx;
+    int index = h->hash_make_key(item);
+    int cnt = 0;
+
+    if (index < h->floor) index = h->floor;
+
+    cnx = gap_get(h->data, index);
+#ifdef DEBUG
+    fprintf(stderr, "searching %d\n", index);
+#endif
+    while (cnx != FREE) {
+        if (cnt++ > hash_size) return -1;
+
+        if (!h->cmp_item(cnx, item))
+            break;
+
+        index = hash_next_index(h, index);
+        cnx = gap_get(h->data, index);
+#ifdef DEBUG
+        fprintf(stderr, "searching %d\n", index);
+#endif
+    } 
+    if (cnx == FREE) return -1;
+    return index;
+}
+
+/* says if we should swap the bubble (element that's going up) and the current
+ * indexed element.
+ * index: current insertion index
+ * wanted_index: index wanted by the element at the current index
+ * bubble: bubble wanted index
+ * floor: index of lowest wanted index (or index of the highest wrapped wanted
+ * index)
+ * wrapped: whether we wrapped or not (if we reach the floor from below after
+ * wrapping, we should swap as it's a 'highest' element pushing the floor up.
+ * it we're inserting a higher-than bottom element at the floor, it should
+ * bubble up).
+ */
+static int i_should_swap(int index, int wanted_index, int bubble_index, int floor, int wrapped)
+{
+    int res;
+
+    if ((index == floor))
+        res = wrapped;
+    else
+        res = bubble_index < wanted_index;
+
+#if DEBUG 
+    fprintf(stderr, "i_should_swap(%d, %d, %d, %d) = %d\n", index, wanted_index, bubble_index, floor, res);
+#endif
+
+    return res;
+}
+
+int hash_insert(hash* h, hash_item new)
+{
+    int bubble_wanted_index = h->hash_make_key(new);
+    int index = bubble_wanted_index;
+    gap_array* hash = h->data;
+
+    if (h->item_cnt == hash_size)
+        return -1;
+
+    if (index < h->floor) index = h->floor;
+
+    hash_item curr_item = gap_get(hash, index);
+    int orig_floor = h->floor;
+    int wrapped = 0;
+    while (1) {
+        if (curr_item == NULL) {
+#if DEBUG
+            fprintf(stderr, "final insert at %d\n", index);
+#endif
+            gap_set(hash, index, new);
+            h->item_cnt++;
+            return 0;
+        }
+
+        int curr_wanted_index = h->hash_make_key(curr_item);
+
+        if (i_should_swap(index, curr_wanted_index, bubble_wanted_index, orig_floor, wrapped)) {
+            gap_set(h->data, index, new);
+#if DEBUG
+            fprintf(stderr, "intermediate insert [%s] at %d\n", &new->client_addr, index);
+#endif
+            new = curr_item;
+            bubble_wanted_index = curr_wanted_index;
+        }
+
+        index = hash_next_index(h, index);
+        curr_item = gap_get(hash, index);
+
+        if (index == 0) h->floor++;
+        if (index == 0) wrapped = 1;
+    }
+
+    return 0;
+}
+
+
+
+
+static int next_in_right_place(hash* h, hash_item item, int index)
+{
+    if (!item) return 0;
+    int wanted_index = h->hash_make_key(item);
+    return (wanted_index == index);
+}
+
+/* Remove cnx from the hash */
+int hash_remove(hash* h, hash_item item)
+{
+    gap_array* hash = h->data;
+
+    int index = hash_find_index(h, item);
+    if (index == -1) return -1; /* Tried to remove something that isn't there */
+
+    int lower_floor = 0; /* If we remove something below the floor, we'll need to lower it */
+    while (1) {
+        if (index < h->floor) lower_floor = 1;
+        int next_index = hash_next_index(h, index);
+        hash_item next = gap_get(h->data, next_index);
+        if ((next == FREE) || next_in_right_place(h, next, next_index)) {
+            h->item_cnt--;
+            if (lower_floor) h->floor--;
+            gap_set(hash, index, FREE);
+            return 0;
+        }
+
+        gap_set(hash, index, next);
+
+        index = hash_next_index(h, index);;
+#if DEBUG
+        fprintf(stderr, "index %d floor %d\n", index, h->floor);
+#endif
+    }
+    return 0;
+}
+
+
+#include <stdio.h>
+#include <string.h>
+#define STR_LENGTH 16
+struct hash_item {
+    int wanted_index;
+    char str[STR_LENGTH];
+};
+void hash_dump(hash* h, char* filename)
+{
+    char str[STR_LENGTH];
+    FILE* out = fopen(filename, "w");
+
+    if (!out) {
+        perror(filename);
+        exit(1);
+    }
+    
+    fprintf(out, "<hash floor=%d elem=%d>\n", h->floor, h->item_cnt);
+    for (int i = 0; i < hash_size; i++) {
+        hash_item item = gap_get(h->data, i);
+        int idx = 0;
+
+        memset(str, 0, STR_LENGTH);
+        if (item) {
+            idx = h->hash_make_key(item);
+            memcpy(str, item->str, STR_LENGTH);
+        }
+        fprintf(out, "\t%d:%d:%s\n", i, idx, str);
+    }
+    fprintf(out, "</hash>\n");
+    fclose(out);
+}

hash.h

@@ -0,0 +1,16 @@
+
+
+typedef struct hash hash;
+typedef struct hash_item* hash_item;
+typedef int (*hash_make_key_fn)(hash_item item);
+
+/* Function that compares two items: returns 0 if they are the same */
+typedef int (*hash_cmp_item_fn)(hash_item item1, hash_item item2);
+
+hash* hash_init(hash_make_key_fn make_key, hash_cmp_item_fn cmp_item);
+int hash_find_index(hash* h, hash_item item);
+int hash_insert(hash* h, hash_item new);
+int hash_remove(hash* h, hash_item item);
+
+
+void hash_dump(hash* h, char* filename); /* For development only */

hashtest/Makefile

@@ -0,0 +1,6 @@
+
+OBJ=../hash.o ../gap.o htest.o
+
+htest: $(OBJ)
+	$(CC) -o htest $(OBJ)
+

hashtest/delete.tst

@@ -0,0 +1,8 @@
+# Basic delete
+a 10 aa
+a 10 ab
+a 10 ac
+a 20 ba
+a 21 bb
+
+d 21 bb

hashtest/delete.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:10:ac
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:20:ba
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_at_end.tst

@@ -0,0 +1,9 @@
+# Delete inside a block with nothing after
+
+a 10 aa
+a 10 ab
+a 12 ac
+a 13 ad
+a 14 ae
+
+d 14 ae

hashtest/delete_at_end.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:12:ac
+	13:13:ad
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_below_floor.tst

@@ -0,0 +1,9 @@
+# wrap-around and delete below floor
+a 2 ba
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 2 bb
+
+d 30 ab

hashtest/delete_below_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=1 elem=5>
+	0:30:ad
+	1:0:
+	2:2:ba
+	3:2:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/delete_discont.tst

@@ -0,0 +1,10 @@
+# delete in a discontinuous block
+
+a 10 aa
+a 11 ab
+a 12 ac
+a 14 ad
+a 10 bc
+
+d 11 ab
+

hashtest/delete_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:bc
+	12:12:ac
+	13:0:
+	14:14:ad
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_empty.tst

@@ -0,0 +1,11 @@
+# Delete an unexisting element. And on an empty hash
+
+a 10 aa
+
+d 10 ab
+d 12 bc
+
+# Empty for real
+d 10 aa
+
+d 10 aa

hashtest/delete_empty.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=0>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_full.tst

@@ -0,0 +1,39 @@
+# delete on a full hash
+
+# First, fill the hash :-)
+
+a 0 aa
+a 1 ab
+a 2 ac
+a 3 ad
+a 4 ae
+a 5 af
+a 6 ag 
+a 7 ah
+a 8 ai
+a 9 af
+a 10 ba
+a 11 bb
+a 12 bc
+a 13 bd
+a 14 be 
+a 15 bf
+a 16 bg
+a 17 bh
+a 18 bi
+a 19 bj
+a 20 ca
+a 21 cb
+a 22 cd
+a 23 ce
+a 24 cf
+a 25 cg
+a 26 ch
+a 27 ci
+a 28 cj
+a 29 ck
+a 30 da
+a 31 db
+
+
+d 21 cb

hashtest/delete_full.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=31>
+	0:0:aa
+	1:1:ab
+	2:2:ac
+	3:3:ad
+	4:4:ae
+	5:5:af
+	6:6:ag
+	7:7:ah
+	8:8:ai
+	9:9:af
+	10:10:ba
+	11:11:bb
+	12:12:bc
+	13:13:bd
+	14:14:be
+	15:15:bf
+	16:16:bg
+	17:17:bh
+	18:18:bi
+	19:19:bj
+	20:20:ca
+	21:0:
+	22:22:cd
+	23:23:ce
+	24:24:cf
+	25:25:cg
+	26:26:ch
+	27:27:ci
+	28:28:cj
+	29:29:ck
+	30:30:da
+	31:31:db
+</hash>

hashtest/delete_middle.tst

@@ -0,0 +1,10 @@
+# Delete inside a block with something discontinuous
+
+a 10 aa
+a 10 ab
+a 12 ac
+a 13 ad
+a 14 ae
+
+# ab shifts, ac and next doesn't
+d 10 aa

hashtest/delete_middle.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=4>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:ab
+	11:0:
+	12:12:ac
+	13:13:ad
+	14:14:ae
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/delete_wrap.tst

@@ -0,0 +1,8 @@
+# Basic delete when wrapping, between wrap and floor
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ba
+a 30 bb
+
+d 30 ac

hashtest/delete_wrap.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=2 elem=4>
+	0:30:ba
+	1:30:bb
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/delete_wrap_at_end.tst

@@ -0,0 +1,10 @@
+# Delete inside a block with wrapping, with something after
+
+a 30 aa
+a 30 ab
+a 30 ac
+a 1 ad
+a 3 ae
+
+# shift ad but not ae
+d 14 ae

hashtest/delete_wrap_at_end.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=1 elem=5>
+	0:30:ac
+	1:1:ad
+	2:0:
+	3:3:ae
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/delete_wrap_below_floor.tst

@@ -0,0 +1,8 @@
+# delete before wrap
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+
+# shift ac and ad
+d 30 ab

hashtest/delete_wrap_below_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=1 elem=3>
+	0:30:ad
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/delete_wrap_discont.tst

@@ -0,0 +1,11 @@
+# Delete with wrapping in discontinuous group
+
+a 30 aa
+a 30 ab
+a 30 ac
+a 31 ad
+a 2 ba
+a 3 bb
+
+# shift ac and ad but not ba and bb
+d 30 ab

hashtest/delete_wrap_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=1 elem=5>
+	0:31:ad
+	1:0:
+	2:2:ba
+	3:3:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ac
+</hash>

hashtest/htest.c

@@ -0,0 +1,105 @@
+/* Wee testing program from the hash code:
+ * htest <script> <dump>
+ *
+ * scripts are a list of operations:
+ * a $index $string
+ * => add an element at specified index
+ * d $index $string
+ * => remove an element
+ * s $index $string
+ * => prints the actual element index, if it's there
+ *
+ * The hash is dumped to the dump file at each iteration.
+ */
+
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "../hash.h"
+
+
+#define STR_LENGTH 16
+struct hash_item {
+    int wanted_index;
+    char str[STR_LENGTH];
+};
+
+
+
+
+static int cmp_item(hash_item item1, hash_item item2)
+{
+    return strcmp(item1->str, item2->str);
+}
+
+
+static int hash_make_key(hash_item item)
+{
+    return item->wanted_index;
+}
+
+
+static void htest_next_key(FILE* f, char* action, int* key, char str[STR_LENGTH])
+{
+
+    int res = 0;
+    while ((res != 3) && (res != EOF))
+        res = fscanf(f, "%c %d %s\n", action, key, str);
+    if (res == EOF) exit(0);
+}
+
+int main(int argc, char* argv[])
+{
+    hash* h = hash_init(&hash_make_key, &cmp_item);
+    char action;
+    hash_item item;
+    int line = 0;
+    FILE* f;
+
+    if (argc != 3) {
+        fprintf(stderr, "Usage: htest <script file> <dump file>\n");
+        exit(1);
+    }
+    char* script_file = argv[1];
+    char* dump_file = argv[2];
+    f = fopen(argv[1], "r");
+    if (!f) {
+        perror(script_file);
+        exit(1);
+    }
+
+    while (1) {
+        item= malloc(sizeof(*item));
+        action = ' ';
+
+        line++;
+        htest_next_key(f, &action, &item->wanted_index, item->str);
+        fprintf(stderr, "action %d: %c %d %s\n", line, action, item->wanted_index, item->str);
+
+        switch (action) {
+        case 'a': /* add */
+            fprintf(stderr, "inserting [%s] at %d\n", item->str, item->wanted_index);
+            hash_insert(h, item);
+            break;
+
+        case 'd': /* del */
+            fprintf(stderr, "removing [%s] at %d\n", item->str, item->wanted_index);
+            hash_remove(h, item);
+            break;
+
+        case 's': /* search */
+            fprintf(stderr, "searching\n");
+            int i = hash_find_index(h, item);
+            fprintf(stderr, "searching %d[%s]: %d\n", item->wanted_index, item->str, i);
+            break;
+
+        case 'q': /* quit */
+            exit(1);
+        }
+        hash_dump(h, dump_file);
+    }
+    return 0;
+}

hashtest/insert.tst

@@ -0,0 +1,6 @@
+# Basic insertions
+a 10 aa
+a 10 ab
+a 10 ac
+a 20 ba
+a 21 bb

hashtest/insert.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=5>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:ab
+	12:10:ac
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:20:ba
+	21:21:bb
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/insert_discont.tst

@@ -0,0 +1,8 @@
+# insert and bubble with single empty space
+
+a 10 aa
+a 11 ab
+a 12 ac
+a 14 ad
+a 10 bc
+

hashtest/insert_discont.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=5>
+	0:0:
+	1:0:
+	2:0:
+	3:0:
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:10:aa
+	11:10:bc
+	12:11:ab
+	13:12:ac
+	14:14:ad
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:0:
+	31:0:
+</hash>

hashtest/insert_full.tst

@@ -0,0 +1,40 @@
+# Insert on a full hash
+
+# First, fill the hash :-)
+
+a 0 aa
+a 1 ab
+a 2 ac
+a 3 ad
+a 4 ae
+a 5 af
+a 6 ag 
+a 7 ah
+a 8 ai
+a 9 af
+a 10 ba
+a 11 bb
+a 12 bc
+a 13 bd
+a 14 be 
+a 15 bf
+a 16 bg
+a 17 bh
+a 18 bi
+a 19 bj
+a 20 ca
+a 21 cb
+a 22 cd
+a 23 ce
+a 24 cf
+a 25 cg
+a 26 ch
+a 27 ci
+a 28 cj
+a 29 ck
+a 30 da
+a 31 db
+
+# it's full!
+a 20 zz
+a 31 za

hashtest/insert_full.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=0 elem=32>
+	0:0:aa
+	1:1:ab
+	2:2:ac
+	3:3:ad
+	4:4:ae
+	5:5:af
+	6:6:ag
+	7:7:ah
+	8:8:ai
+	9:9:af
+	10:10:ba
+	11:11:bb
+	12:12:bc
+	13:13:bd
+	14:14:be
+	15:15:bf
+	16:16:bg
+	17:17:bh
+	18:18:bi
+	19:19:bj
+	20:20:ca
+	21:21:cb
+	22:22:cd
+	23:23:ce
+	24:24:cf
+	25:25:cg
+	26:26:ch
+	27:27:ci
+	28:28:cj
+	29:29:ck
+	30:30:da
+	31:31:db
+</hash>

hashtest/insert_full_floor.tst

@@ -0,0 +1,7 @@
+# wrap-around and insert at full floor
+a 2 ba
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 2 bb

hashtest/insert_full_floor.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=2 elem=6>
+	0:30:ac
+	1:30:ad
+	2:2:ba
+	3:2:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/insert_wrap.tst

@@ -0,0 +1,7 @@
+# wrap-around and insert above floor
+a 30 aa
+a 30 ab
+a 30 ac
+a 30 ad
+a 0 ba
+a 0 bb

hashtest/insert_wrap.tst.ref

@@ -0,0 +1,34 @@
+<hash floor=2 elem=6>
+	0:30:ac
+	1:30:ad
+	2:0:ba
+	3:0:bb
+	4:0:
+	5:0:
+	6:0:
+	7:0:
+	8:0:
+	9:0:
+	10:0:
+	11:0:
+	12:0:
+	13:0:
+	14:0:
+	15:0:
+	16:0:
+	17:0:
+	18:0:
+	19:0:
+	20:0:
+	21:0:
+	22:0:
+	23:0:
+	24:0:
+	25:0:
+	26:0:
+	27:0:
+	28:0:
+	29:0:
+	30:30:aa
+	31:30:ab
+</hash>

hashtest/mkrand.pl

@@ -0,0 +1,41 @@
+#! /usr/bin/perl
+
+# Creates a script of random accesses and deletes
+
+use strict;
+
+
+my $i = 0;
+sub mkstr {
+    $i++;
+    return chr(ord('a') + ($i / 26) % 26) . chr(ord('a') + $i % 26);
+}
+
+my @elems;
+
+
+sub add_elem {
+    my $val = int(rand(32));
+    my $str = mkstr($val);
+    push @elems, "$val $str";
+    print "a $val $str\n";
+}
+
+sub del_elem {
+    my $remove = splice(@elems, rand @elems, 1);
+    print "d $remove\n";
+}
+
+while (1) {
+    if (@elems < 5) {
+        add_elem;
+    } elsif (@elems > 28) {
+        del_elem;
+    } else {
+        if (rand() < .5) {
+            add_elem;
+        } else {
+            del_elem;
+        }
+    }
+}

hashtest/run

@@ -0,0 +1,30 @@
+#! /usr/bin/perl -w
+
+# This runs all the tests.
+
+# Tests scripts are in *.tst files.
+# Corresponding output is put in *.out.
+# Reference output is put in *.ref.
+# Any discrepency will be reported!
+
+use strict;
+
+my @res;
+foreach my $fn (`ls *.tst`) {
+    chomp $fn;
+    my $cmd = "./htest $fn $fn.out";
+    print "$cmd\n";
+    `$cmd`;
+    my $res = system("diff -u $fn.ref $fn.out");
+    push @res, [$fn, ($res == 0 ? "OK" : "*KO*")];
+}
+
+format =
+@<<<<<<<<<<<<<<<<<<<<<<<<<< @>>>
+$_->[0], $_->[1]
+.
+
+
+#format_name STDOUT test_result;
+map { write; } @res;
+