rax-test.c

/* Rax -- A radix tree implementation.
 *
 * Copyright (c) 2017, Salvatore Sanfilippo <antirez at gmail dot com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <assert.h>

#include "rax.h"

/* ---------------------------------------------------------------------------
 * Simple hash table implementation, no rehashing, just chaining. This is
 * used in order to test the radix tree implementation against something that
 * will always "tell the truth" :-) */

#define HT_TABLE_SIZE 100000 /* This is huge but we want it fast enough without
                              * reahshing needed. */
typedef struct htNode {
    uint64_t keylen;
    unsigned char *key;
    void *data;
    struct htNode *next;
} htNode;

typedef struct ht {
    uint64_t numele;
    htNode *table[HT_TABLE_SIZE];
} hashtable;

/* Create a new hash table. */
hashtable *htNew(void) {
    hashtable *ht = calloc(1,sizeof(*ht));
    ht->numele = 0;
    return ht;
}

/* djb2 hash function. */
uint32_t htHash(unsigned char *s, size_t len) {
    uint32_t hash = 5381;
    for (size_t i = 0; i < len; i++)
	hash = hash * 33 + s[i];
    return hash % HT_TABLE_SIZE;
}

/* Low level hash table lookup function. */
htNode *htRawLookup(hashtable *t, unsigned char *s, size_t len, uint32_t *hash, htNode ***parentlink) {
    uint32_t h = htHash(s,len);
    if (hash) *hash = h;
    htNode *n = t->table[h];
    if (parentlink) *parentlink = &t->table[h];
    while(n) {
        if (n->keylen == len && memcmp(n->key,s,len) == 0) return n;
        if (parentlink) *parentlink = &n->next;
        n = n->next;
    }
    return NULL;
}

/* Add an elmenet to the hash table, return 1 if the element is new,
 * 0 if it existed and the value was updated to the new one. */
int htAdd(hashtable *t, unsigned char *s, size_t len, void *data) {
    uint32_t hash;
    htNode *n = htRawLookup(t,s,len,&hash,NULL);

    if (!n) {
        n = malloc(sizeof(*n));
        n->key = malloc(len);
        memcpy(n->key,s,len);
        n->keylen = len;
        n->data = data;
        n->next = t->table[hash];
        t->table[hash] = n;
        t->numele++;
        return 1;
    } else {
        n->data = data;
        return 0;
    }
}

/* Remove the specified element, returns 1 on success, 0 if the element
 * was not there already. */
int htRem(hashtable *t, unsigned char *s, size_t len) {
    htNode **parentlink;
    htNode *n = htRawLookup(t,s,len,NULL,&parentlink);

    if (!n) return 0;
    *parentlink = n->next;
    free(n->key);
    free(n);
    t->numele--;
    return 1;
}

void *htNotFound = (void*)"ht-not-found";

/* Find an element inside the hash table. Returns htNotFound if the
 * element is not there, otherwise returns the associated value. */
void *htFind(hashtable *t, unsigned char *s, size_t len) {
    htNode *n = htRawLookup(t,s,len,NULL,NULL);
    if (!n) return htNotFound;
    return n->data;
}

/* Free the whole hash table including all the linked nodes. */
void htFree(hashtable *ht) {
    for (int j = 0; j < HT_TABLE_SIZE; j++) {
        htNode *next = ht->table[j];
        while(next) {
            htNode *this = next;
            next = this->next;
            free(this->key);
            free(this);
        }
    }
    free(ht);
}

/* --------------------------------------------------------------------------
 * Utility functions to generate keys, check time usage and so forth.
 * -------------------------------------------------------------------------*/

/* This is a simple Feistel network in order to turn every possible
 * uint32_t input into another "randomly" looking uint32_t. It is a
 * one to one map so there are no repetitions. */
static uint32_t int2int(uint32_t input) {
    uint16_t l = input & 0xffff;
    uint16_t r = input >> 16;
    for (int i = 0; i < 8; i++) {
        uint16_t nl = r;
        uint16_t F = (((r * 31) + (r >> 5) + 7 * 371) ^ r) & 0xffff;
        r = l ^ F;
        l = nl;
    }
    return (r<<16)|l;
}

/* Turn an uint32_t integer into an alphanumerical key and return its
 * length. This function is used in order to generate keys that have
 * a large charset, so that the radix tree can be testsed with many
 * children per node. */
static size_t int2alphakey(char *s, size_t maxlen, uint32_t i) {
    const char *set = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                      "abcdefghijklmnopqrstuvwxyz"
                      "0123456789";
    const size_t setlen = 62;

    if (maxlen == 0) return 0;
    maxlen--; /* Space for null term char. */
    size_t len = 0;
    while(len < maxlen) {
        s[len++] = set[i%setlen];
        i /= setlen;
        if (i == 0) break;
    }
    s[len] = '\0';
    return len;
}

/* Return the UNIX time in microseconds */
long long ustime(void) {
    struct timeval tv;
    long long ust;

    gettimeofday(&tv, NULL);
    ust = ((long long)tv.tv_sec)*1000000;
    ust += tv.tv_usec;
    return ust;
}

/* Turn the integer 'i' into a key according to 'mode'.
 * KEY_INT: Just represents the integer as a string.
 * KEY_UNIQUE_ALPHA: Turn it into a random-looking alphanumerical string
 *                   according to the int2alphakey() function, so that
 *                   at every integer is mapped a different string.
 * KEY_RANDOM: Totally random string up to maxlen bytes.
 * KEY_RANDOM_ALPHA: Alphanumerical random string up to maxlen bytes.
 * KEY_RANDOM_SMALL_CSET: Small charset random strings.
 * KEY_CHAIN: 'i' times the character "A". */
#define KEY_INT 0
#define KEY_UNIQUE_ALPHA 1
#define KEY_RANDOM 2
#define KEY_RANDOM_ALPHA 3
#define KEY_RANDOM_SMALL_CSET 4
#define KEY_CHAIN 5
static size_t int2key(char *s, size_t maxlen, uint32_t i, int mode) {
    if (mode == KEY_INT) {
        return snprintf(s,maxlen,"%lu",(unsigned long)i);
    } else if (mode == KEY_UNIQUE_ALPHA) {
        if (maxlen > 16) maxlen = 16;
        i = int2int(i);
        return int2alphakey(s,maxlen,i);
    } else if (mode == KEY_RANDOM) {
        if (maxlen > 16) maxlen = 16;
        int r = rand() % maxlen;
        for (int i = 0; i < r; i++) s[i] = rand()&0xff;
        return r;
    } else if (mode == KEY_RANDOM_ALPHA) {
        if (maxlen > 16) maxlen = 16;
        int r = rand() % maxlen;
        for (int i = 0; i < r; i++) s[i] = 'A'+rand()%('z'-'A'+1);
        return r;
    } else if (mode == KEY_RANDOM_SMALL_CSET) {
        if (maxlen > 16) maxlen = 16;
        int r = rand() % maxlen;
        for (int i = 0; i < r; i++) s[i] = 'A'+rand()%4;
        return r;
    } else if (mode == KEY_CHAIN) {
        if (i > maxlen) i = maxlen;
        memset(s,'A',i);
        return i;
    } else {
        return 0;
    }
}

/* -------------------------------------------------------------------------- */

/* Perform a fuzz test, returns 0 on success, 1 on error. */
int fuzzTest(int keymode, size_t count, double addprob, double remprob) {
    hashtable *ht = htNew();
    rax *rax = raxNew();

    printf("Fuzz test in mode %d: ", keymode);
    fflush(stdout);

    /* Perform random operations on both the dictionaries. */
    for (size_t i = 0; i < count; i++) {
        unsigned char key[1024];
        uint32_t keylen;

        /* Insert element. */
        if ((double)rand()/RAND_MAX < addprob) {
            keylen = int2key((char*)key,sizeof(key),i,keymode);
            void *val = (void*)(unsigned long)rand();
            /* Stress NULL values more often, they use a special encoding. */
            if (!(rand() % 100)) val = NULL;
            int retval1 = htAdd(ht,key,keylen,val);
            int retval2 = raxInsert(rax,key,keylen,val,NULL);
            if (retval1 != retval2) {
                printf("Fuzz: key insertion reported mismatching value in HT/RAX\n");
                return 1;
            }
        }

        /* Remove element. */
        if ((double)rand()/RAND_MAX < remprob) {
            keylen = int2key((char*)key,sizeof(key),i,keymode);
            int retval1 = htRem(ht,key,keylen);
            int retval2 = raxRemove(rax,key,keylen,NULL);
            if (retval1 != retval2) {
                printf("Fuzz: key deletion of '%.*s' reported mismatching "
                       "value in HT=%d RAX=%d\n",
                       (int)keylen,(char*)key,retval1, retval2);
                printf("%p\n", raxFind(rax,key,keylen));
                printf("%p\n", raxNotFound);
                return 1;
            }
        }
    }

    /* Check that count matches. */
    if (ht->numele != rax->numele) {
        printf("Fuzz: HT / RAX keys count mismatch: %lu vs %lu\n",
            (unsigned long) ht->numele,
            (unsigned long) rax->numele);
        return 1;
    }
    printf("%lu elements inserted\n", (unsigned long)ht->numele);

    /* Check that elements match. */
    raxIterator iter;
    raxStart(&iter,rax);
    raxSeek(&iter,"^",NULL,0);

    size_t numkeys = 0;
    while(raxNext(&iter)) {
        void *val1 = htFind(ht,iter.key,iter.key_len);
        void *val2 = raxFind(rax,iter.key,iter.key_len);
        if (val1 != val2) {
            printf("Fuzz: HT=%p, RAX=%p value do not match "
                   "for key %.*s\n",
                    val1, val2, (int)iter.key_len,(char*)iter.key);
            return 1;
        }
        numkeys++;
    }

    /* Check that the iterator reported all the elements. */
    if (ht->numele != numkeys) {
        printf("Fuzz: the iterator reported %lu keys instead of %lu\n",
            (unsigned long) numkeys,
            (unsigned long) ht->numele);
        return 1;
    }

    raxStop(&iter);
    raxFree(rax);
    htFree(ht);
    return 0;
}

/* Iterator fuzz testing. Compared the items returned by the Rax iterator with
 * a C implementation obtained by sorting the inserted strings in a linear
 * array. */
typedef struct arrayItem {
    unsigned char *key;
    size_t key_len;
} arrayItem;

/* Utility functions used with qsort() in order to sort the array of strings
 * in the same way Rax sorts keys (which is, lexicographically considering
 * every byte an unsigned integer. */
int compareAB(const unsigned char *keya, size_t lena, const unsigned char *keyb, size_t lenb) {
    size_t minlen = (lena <= lenb) ? lena : lenb;
    int retval = memcmp(keya,keyb,minlen);
    if (lena == lenb || retval != 0) return retval;
    return (lena > lenb) ? 1 : -1;
}

int compareArrayItems(const void *aptr, const void *bptr) {
    const arrayItem *a = aptr;
    const arrayItem *b = bptr;
    return compareAB(a->key,a->key_len,b->key,b->key_len);
}

/* Seek an element in the array, returning the seek index (the index inside the
 * array). If the seek is not possible (== operator and key not found or empty
 * array) -1 is returned. */
int arraySeek(arrayItem *array, int count, unsigned char *key, size_t len, char *op) {
    if (count == 0) return -1;
    if (op[0] == '^') return 0;
    if (op[0] == '$') return count-1;

    int eq = 0, lt = 0, gt = 0;
    if (op[1] == '=') eq = 1;
    if (op[0] == '<') lt = 1;
    if (op[0] == '>') gt = 1;

    int i;
    for (i = 0; i < count; i++) {
        int cmp = compareAB(array[i].key,array[i].key_len,key,len);
        if (eq && !cmp) return i;
        if (cmp > 0 && gt) return i;
        if (cmp >= 0 && lt) {
            i--;
            break;
        }
    }
    if (lt && i == count) return count-1;
    if (i < 0 || i >= count) return -1;
    return i;
}

int iteratorFuzzTest(int keymode, size_t count) {
    count = rand()%count;
    rax *rax = raxNew();
    arrayItem *array = malloc(sizeof(arrayItem)*count);

    /* Fill a radix tree and a linear array with some data. */
    unsigned char key[1024];
    size_t j = 0;
    for (size_t i = 0; i < count; i++) {
        uint32_t keylen = int2key((char*)key,sizeof(key),i,keymode);
        void *val = (void*)(unsigned long)htHash(key,keylen);

        if (raxInsert(rax,key,keylen,val,NULL)) {
            array[j].key = malloc(keylen);
            array[j].key_len = keylen;
            memcpy(array[j].key,key,keylen);
            j++;
        }
    }
    count = rax->numele;

    /* Sort the array. */
    qsort(array,count,sizeof(arrayItem),compareArrayItems);

    /* Perform a random seek operation. */
    uint32_t keylen = int2key((char*)key,sizeof(key),
        rand()%(count ? count : 1),keymode);
    raxIterator iter;
    raxStart(&iter,rax);
    char *seekops[] = {"==",">=","<=",">","<","^","$"};
    char *seekop = seekops[rand() % 7];
    raxSeek(&iter,seekop,key,keylen);
    int seekidx = arraySeek(array,count,key,keylen,seekop);

    int next = rand() % 2;
    int iteration = 0;
    while(1) {
        int rax_res;
        int array_res;
        unsigned char *array_key = NULL;
        size_t array_key_len = 0;

        array_res = (seekidx == -1) ? 0 : 1;
        if (array_res) {
            if (next && seekidx == (signed)count) array_res = 0;
            if (!next && seekidx == -1) array_res = 0;
            if (array_res != 0) {
                array_key = array[seekidx].key;
                array_key_len = array[seekidx].key_len;
            }
        }

        if (next) {
            rax_res = raxNext(&iter);
            if (array_res) seekidx++;
        } else {
            rax_res = raxPrev(&iter);
            if (array_res) seekidx--;
        }

        /* Both the iteratos should agree about EOF. */
        if (array_res != rax_res) {
            printf("Iter fuzz: iterators do not agree about EOF "
                   "at iteration %d:  "
                   "array_more=%d rax_more=%d next=%d\n",
                   iteration, array_res, rax_res, next);
            return 1;
        }
        if (array_res == 0) break; /* End of iteration reached. */

        /* Check that the returned keys are the same. */
        if (iter.key_len != array_key_len ||
            memcmp(iter.key,array_key,iter.key_len))
        {
            printf("Iter fuzz: returned element %d mismatch\n", iteration);
            if (keymode != KEY_RANDOM) {
                printf("%.*s (iter) VS %.*s (array) next=%d\n",
                    (int)iter.key_len, (char*)iter.key,
                    (int)array_key_len, (char*)array_key,
                    next);
            }
            return 1;
        }
        iteration++;
    }

    for (unsigned int i = 0; i < count; i++) free(array[i].key);
    free(array);
    raxStop(&iter);
    raxFree(rax);
    return 0;
}

/* Test the random walk function. */
int randomWalkTest(void) {
    rax *t = raxNew();
    char *toadd[] = {"alligator","alien","baloon","chromodynamic","romane","romanus","romulus","rubens","ruber","rubicon","rubicundus","all","rub","ba",NULL};

    long numele;
    for (numele = 0; toadd[numele] != NULL; numele++) {
        raxInsert(t,(unsigned char*)toadd[numele],
                    strlen(toadd[numele]),(void*)numele,NULL);
    }

    raxIterator iter;
    raxStart(&iter,t);
    raxSeek(&iter,"^",NULL,0);
    int maxloops = 100000;
    while(raxRandomWalk(&iter,0) && maxloops--) {
        int nulls = 0;
        for (long i = 0; i < numele; i++) {
            if (toadd[i] == NULL) {
                nulls++;
                continue;
            }
            if (strlen(toadd[i]) == iter.key_len &&
                memcmp(toadd[i],iter.key,iter.key_len) == 0)
            {
                toadd[i] = NULL;
                nulls++;
            }
        }
        if (nulls == numele) break;
    }
    if (maxloops == 0) {
        printf("randomWalkTest() is unable to report all the elements "
               "after 100k iterations!\n");
        return 1;
    }
    raxStop(&iter);
    raxFree(t);
    return 0;
}

int iteratorUnitTests(void) {
    rax *t = raxNew();
    char *toadd[] = {"alligator","alien","baloon","chromodynamic","romane","romanus","romulus","rubens","ruber","rubicon","rubicundus","all","rub","ba",NULL};

    for (int x = 0; x < 10000; x++) rand();

    long items = 0;
    while(toadd[items] != NULL) items++;

    for (long i = 0; i < items; i++)
        raxInsert(t,(unsigned char*)toadd[i],strlen(toadd[i]),(void*)i,NULL);

    raxIterator iter;
    raxStart(&iter,t);

    struct {
        char *seek;
        size_t seeklen;
        char *seekop;
        char *expected;
    } tests[] = {
        /* Seek value. */       /* Expected result. */
        {"rpxxx",5,"<=",         "romulus"},
        {"rom",3,">=",           "romane"},
        {"rub",3,">=",           "rub"},
        {"rub",3,">",            "rubens"},
        {"rub",3,"<",            "romulus"},
        {"rom",3,">",            "romane"},
        {"chro",4,">",           "chromodynamic"},
        {"chro",4,"<",           "baloon"},
        {"chromz",6,"<",         "chromodynamic"},
        {"",0,"^",               "alien"},
        {"zorro",5,"<=",         "rubicundus"},
        {"zorro",5,"<",          "rubicundus"},
        {"zorro",5,"<",          "rubicundus"},
        {"",0,"$",               "rubicundus"},
        {"ro",2,">=",            "romane"},
        {"zo",2,">",             NULL},
        {"zo",2,"==",            NULL},
        {"romane",6,"==",        "romane"}
    };

    for (int i = 0; tests[i].expected != NULL; i++) {
        raxSeek(&iter,tests[i].seekop,(unsigned char*)tests[i].seek,
                tests[i].seeklen);
        int retval = raxNext(&iter);

        if (tests[i].expected != NULL) {
            if (strlen(tests[i].expected) != iter.key_len ||
                memcmp(tests[i].expected,iter.key,iter.key_len) != 0)
            {
                printf("Iterator unit test error: "
                       "test %d, %s expected, %.*s reported\n",
                       i, tests[i].expected, (int)iter.key_len,
                       (char*)iter.key);
                return 1;
            }
        } else {
            if (retval != 0) {
                printf("Iterator unit test error: "
                       "EOF expected in test %d\n", i);
                return 1;
            }
        }
    }
    raxStop(&iter);
    raxFree(t);
    return 0;
}

/* Regression test #1: Iterator wrong element returned after seek. */
int regtest1(void) {
    rax *rax = raxNew();
    raxInsert(rax,(unsigned char*)"LKE",3,(void*)(long)1,NULL);
    raxInsert(rax,(unsigned char*)"TQ",2,(void*)(long)2,NULL);
    raxInsert(rax,(unsigned char*)"B",1,(void*)(long)3,NULL);
    raxInsert(rax,(unsigned char*)"FY",2,(void*)(long)4,NULL);
    raxInsert(rax,(unsigned char*)"WI",2,(void*)(long)5,NULL);

    raxIterator iter;
    raxStart(&iter,rax);
    raxSeek(&iter,">",(unsigned char*)"FMP",3);
    if (raxNext(&iter)) {
        if (iter.key_len != 2 ||
            memcmp(iter.key,"FY",2))
        {
            printf("Regression test 1 failed: 'FY' expected, got: '%.*s'\n",
                (int)iter.key_len, (char*)iter.key);
            return 1;
        }
    }

    raxStop(&iter);
    raxFree(rax);
    return 0;
}

/* Regression test #2: Crash when mixing NULL and not NULL values. */
int regtest2(void) {
    rax *rt = raxNew();
    raxInsert(rt,(unsigned char *)"a",1,(void *)100,NULL);
    raxInsert(rt,(unsigned char *)"ab",2,(void *)101,NULL);
    raxInsert(rt,(unsigned char *)"abc",3,(void *)NULL,NULL);
    raxInsert(rt,(unsigned char *)"abcd",4,(void *)NULL,NULL);
    raxInsert(rt,(unsigned char *)"abc",3,(void *)102,NULL);
    raxFree(rt);
    return 0;
}

/* Regression test #3: Wrong access at node value in raxRemoveChild()
 * when iskey == 1 and isnull == 1: the memmove() was performed including
 * the value length regardless of the fact there was no actual value.
 *
 * Note that this test always returns success but will trigger a
 * Valgrind error. */
int regtest3(void) {
    rax *rt = raxNew();
    raxInsert(rt, (unsigned char *)"D",1,(void*)1,NULL);
    raxInsert(rt, (unsigned char *)"",0,NULL,NULL);
    raxRemove(rt, (unsigned char *)"D",1,NULL);
    raxFree(rt);
    return 0;
}

void benchmark(void) {
    for (int mode = 0; mode < 2; mode++) {
        printf("Benchmark with %s keys:\n",
            (mode == 0) ? "integer" : "alphanumerical");
        rax *t = raxNew();
        long long start = ustime();
        for (int i = 0; i < 5000000; i++) {
            char buf[64];
            int len = int2key(buf,sizeof(buf),i,mode);
            raxInsert(t,(unsigned char*)buf,len,(void*)(long)i,NULL);
        }
        printf("Insert: %f\n", (double)(ustime()-start)/1000000);
        printf("%llu total nodes\n", (unsigned long long)t->numnodes);
        printf("%llu total elements\n", (unsigned long long)t->numele);

        start = ustime();
        for (int i = 0; i < 5000000; i++) {
            char buf[64];
            int len = int2key(buf,sizeof(buf),i,mode);
            void *data = raxFind(t,(unsigned char*)buf,len);
            if (data != (void*)(long)i) {
                printf("Issue with %s: %p instead of %p\n", buf,
                    data, (void*)(long)i);
            }
        }
        printf("Linear lookup: %f\n", (double)(ustime()-start)/1000000);

        start = ustime();
        for (int i = 0; i < 5000000; i++) {
            char buf[64];
            int r = rand() % 5000000;
            int len = int2key(buf,sizeof(buf),r,mode);
            void *data = raxFind(t,(unsigned char*)buf,len);
            if (data != (void*)(long)r) {
                printf("Issue with %s: %p instead of %p\n", buf,
                    data, (void*)(long)r);
            }
        }
        printf("Random lookup: %f\n", (double)(ustime()-start)/1000000);

        start = ustime();
        for (int i = 0; i < 5000000; i++) {
            char buf[64];
            int len = int2key(buf,sizeof(buf),i,mode);
            buf[i%len] = '!'; /* "!" is never set into keys. */
            void *data = raxFind(t,(unsigned char*) buf,len);
            if (data != raxNotFound) {
                printf("Failed lookup did not reported NOT FOUND!\n");
            }
        }
        printf("Failed lookup: %f\n", (double)(ustime()-start)/1000000);

        start = ustime();
        for (int i = 0; i < 5000000; i++) {
            char buf[64];
            int len = int2key(buf,sizeof(buf),i,mode);
            int retval = raxRemove(t,(unsigned char*)buf,len,NULL);
            assert(retval == 1);
        }
        printf("Deletion: %f\n", (double)(ustime()-start)/1000000);

        printf("%llu total nodes\n", (unsigned long long)t->numnodes);
        printf("%llu total elements\n", (unsigned long long)t->numele);
        raxFree(t);
    }
}

int main(int argc, char **argv) {
    srand(1234);

    /* Tests to run by default are set here. */
    int do_benchmark = 0;
    int do_units = 1;
    int do_fuzz = 1;
    int do_regression = 1;

    /* If the user passed arguments, override the tests to run. */
    if (argc > 1) {
        do_benchmark = 0;
        do_units = 0;
        do_fuzz = 0;
        do_regression = 0;

        for (int i = 1; i < argc; i++) {
            if (!strcmp(argv[i],"--bench")) {
                do_benchmark = 1;
            } else if (!strcmp(argv[i],"--fuzz")) {
                do_fuzz = 1;
            } else if (!strcmp(argv[i],"--units")) {
                do_units = 1;
            } else if (!strcmp(argv[i],"--regression")) {
                do_regression = 1;
            } else {
                fprintf(stderr, "Usage: %s [--bench] [--fuzz] [--units] "
                                "[--regression]\n", argv[0]);
                exit(1);
            }
        }
    }

    int errors = 0;

    if (do_units) {
        printf("Unit tests: "); fflush(stdout);
        if (randomWalkTest()) errors++;
        if (iteratorUnitTests()) errors++;
        if (errors == 0) printf("OK\n");
    }

    if (do_regression) {
        printf("Performing regression tests: "); fflush(stdout);
        if (regtest1()) errors++;
        if (regtest2()) errors++;
        if (regtest3()) errors++;
        if (errors == 0) printf("OK\n");
    }

    if (do_fuzz) {
        for (int i = 0; i < 10; i++) {
            double alpha = (double)rand() / RAND_MAX;
            double beta = 1-alpha;
            if (fuzzTest(KEY_INT,rand()%10000,alpha,beta)) errors++;
            if (fuzzTest(KEY_UNIQUE_ALPHA,rand()%10000,alpha,beta)) errors++;
            if (fuzzTest(KEY_RANDOM,rand()%10000,alpha,beta)) errors++;
            if (fuzzTest(KEY_RANDOM_ALPHA,rand()%10000,alpha,beta)) errors++;
            if (fuzzTest(KEY_RANDOM_SMALL_CSET,rand()%10000,alpha,beta)) errors++;
        }

        if (fuzzTest(KEY_INT,1000000,.7,.3)) errors++;
        if (fuzzTest(KEY_UNIQUE_ALPHA,1000000,.7,.3)) errors++;
        if (fuzzTest(KEY_RANDOM,1000000,.7,.3)) errors++;
        if (fuzzTest(KEY_RANDOM_ALPHA,1000000,.7,.3)) errors++;
        if (fuzzTest(KEY_RANDOM_SMALL_CSET,1000000,.7,.3)) errors++;
        if (fuzzTest(KEY_CHAIN,1000,.7,.3)) errors++;
        printf("Iterator fuzz test: "); fflush(stdout);
        for (int i = 0; i < 10000; i++) {
            if (iteratorFuzzTest(KEY_INT,100)) errors++;
            if (iteratorFuzzTest(KEY_UNIQUE_ALPHA,100)) errors++;
            if (iteratorFuzzTest(KEY_RANDOM_ALPHA,1000)) errors++;
            if (iteratorFuzzTest(KEY_RANDOM,1000)) errors++;
            if (!(i % 50)) {
                printf(".");
                fflush(stdout);
            }
        }
        printf("\n");
    }

    if (do_benchmark) {
        benchmark();
    }

    if (errors) {
        printf("!!! WARNING !!!: %d errors found\n", errors);
    } else {
        printf("OK! \\o/\n");
    }
    return errors;
}