Esempio n. 1
0
/**
 * @brief TEST_CASE - Sanity test of some key skiplist APIs using integers.
 */
static int simple( void )
{
	unsigned int i;
	skiplist_node_t *iter;
	skiplist_t *skiplist;

	skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, 5, int_compare, int_fprintf, NULL );
	if( !skiplist )
		return -1;

	if( skiplist_contains( skiplist, 10, NULL ) )
		return -1;

	if( !skiplist_remove( skiplist, 10 ) )
		return -1;

	for( i = 0; i < 10; ++i )
	{
		if( skiplist_insert( skiplist, i ) )
			return -1;
		if( !skiplist_contains( skiplist, i, NULL ) )
			return -1;
	}

	for( i = 0; i < 100; ++i )
	{
		unsigned int value = rand();
		if( skiplist_insert( skiplist, value ) )
			return -1;
		if( !skiplist_contains( skiplist, value, NULL ) )
			return -1;
	}

	for( i = 5; i < 10; ++i )
		if( skiplist_remove( skiplist, i ) )
			return -1;

	for( iter = skiplist_begin( skiplist );
	     iter != skiplist_end();
	     iter = skiplist_next( iter ) )
	{
		uintptr_t value = skiplist_node_value( iter, NULL );
		if( value >= 5 && value < 10 )
			return -1;
	}

	for( i = 0; i < skiplist_size( skiplist, NULL ); ++i )
		skiplist_at_index( skiplist, i, NULL );

	if( skiplist_fprintf_filename( "simple.dot", skiplist ) )
		return -1;

	skiplist_destroy( skiplist );

	return 0;
}
Esempio n. 2
0
/**
 * @brief TEST_CASE - Confirms incorrect inputs are handled gracefully for skiplist_fprintf.
 */
static int abuse_skiplist_fprintf( void )
{
	skiplist_t *skiplist;

	skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, 5, int_compare, int_fprintf, NULL );
	if( !skiplist )
		return -1;

	skiplist_fprintf( NULL, skiplist );
	skiplist_fprintf( stdout, NULL );

	skiplist_destroy( skiplist );
	return 0;
}
Esempio n. 3
0
int
main(int argc, char **argv)
{
    ut_init(basename(argv[0]));

    ut_testing("skiplist_create(6, 50, libhl_cmp_keys_int32, free)");
    skiplist_t *skl = skiplist_create(6, 50, libhl_cmp_keys_int32, free);
    if (skl)
        ut_success();
    else
        ut_failure("Can't create a new binomial heap");

    ut_testing("skiplist_insert(0..99)");
    int i;
    for (i = 0; i < 100; i++) { 
        char *val = malloc(4);
        snprintf(val, 4, "%d", i);
        skiplist_insert(skl, &i, sizeof(i), val);
    }
    ut_validate_int(skiplist_count(skl), 100);

    int test_key = 50;
    ut_testing("skiplist_search(50) = \"50\"");
    char *val = skiplist_search(skl, &test_key, sizeof(int));
    ut_validate_string(val, "50");

    
    ut_testing("skiplist_remove(50, &old_value)");
    val = NULL;
    int rc = skiplist_remove(skl, &test_key, sizeof(int), (void **)&val);
    ut_validate_int(rc, 0);

    ut_testing("old_value is \"50\"");
    ut_validate_string(val, "50");
    free(val);

    ut_testing("skiplist_search(50) = NULL");

    val = skiplist_search(skl, &test_key, sizeof(int));
    ut_validate_string(val, NULL);


    skiplist_destroy(skl);

    ut_summary();

    return ut_failed;
}
Esempio n. 4
0
/**
 * @brief TEST_CASE - Confirms incorrect inputs are handled gracefully for skiplist_next.
 */
static int abuse_skiplist_next( void )
{
	skiplist_t *skiplist;

	skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, 5, int_compare, int_fprintf, NULL );
	if( !skiplist )
		return -1;

	if( skiplist_insert( skiplist, 1 ) )
		return -1;

	if( skiplist_next( NULL ) )
		return -1;

	skiplist_destroy( skiplist );
	return 0;
}
Esempio n. 5
0
/**
 * @brief TEST_CASE - Confirms incorrect inputs are handled gracefully for skiplist_fprintf_filename.
 */
static int abuse_skiplist_fprintf_filename( void )
{
	skiplist_t *skiplist;

	skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, 5, int_compare, int_fprintf, NULL );
	if( !skiplist )
		return -1;

	if( !skiplist_fprintf_filename( NULL, skiplist ) )
		return -1;

	if( !skiplist_fprintf_filename( "valid_filname.txt", NULL ) )
		return -1;

	skiplist_destroy( skiplist );
	return 0;
}
Esempio n. 6
0
/**
 * @brief TEST_CASE - Measures insertion trade off between number of elements in the list and number of links per node.
 */
static int link_trade_off_insert( void )
{
#define MAX_LINKS (SKIPLIST_MAX_LINKS)
#define INSERTIONS_LOG2 (16)

	struct timespec stamps[INSERTIONS_LOG2 + 2];
	FILE *fp;
	unsigned int links;
	unsigned int i;
	const char *seperator;

	fp = fopen( "link_trade_off_insert.gplot", "w" );
	if( !fp ) return -1;
	fprintf(fp, "set term qt\n");
	fprintf(fp, "set key off\n");
	fprintf(fp, "set logscale\n");
	fprintf(fp, "set grid xtics ytics mxtics mytics\n");
	fprintf(fp, "set style textbox opaque noborder\n");
	fprintf(fp, "set title \"Average Insertion Time for Skiplists with Varying Link Counts\"\n");
	fprintf(fp, "set xlabel \"Number of Elements in the Skiplist\"\n");
	fprintf(fp, "set ylabel \"Average Time for One Insertion (ns)\"\n");
	fprintf(fp, "plot " );
	seperator = "";
	for( i = 0; i < MAX_LINKS; ++i )
	{
		fprintf(fp, "%s\"link_trade_off_insert_%u.dat\" using 1:2 with lines lt -1,"
		        "\"\" using 1:2:($0*0+%u) with labels center boxed notitle",
		        seperator, i + 1, i + 1);
		seperator = ",\\\n\t";
	}
	fprintf(fp, "\n");
	fprintf(fp, "pause -1\n");
	fclose( fp );

	for( links = MAX_LINKS; links > 0; --links )
	{
		skiplist_t *skiplist;
		char filename[64];
		unsigned int next;

		sprintf( filename, "link_trade_off_insert_%u.dat", links );
		fp = fopen( filename, "w" );
		if( !fp ) return -1;

		skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, links, int_compare, int_fprintf, NULL );
		if( !skiplist ) return -1;

		next = 0;
		for( i = 0; i < (1 << INSERTIONS_LOG2); ++i )
		{
			/* Sample at powers of 2. */
			if( (i & (i - 1)) == 0 )
			{
				time_stamp( &stamps[next] );

				/* Stop trying if it's taking too long. */
				if( next && time_diff_ns( &stamps[next - 1], &stamps[next] ) > 300000000LLU )
					break;

				++next;
			}

			if( skiplist_insert( skiplist, rand() ) )
				return -1;
		}
		time_stamp( &stamps[next] );
		++next;

		skiplist_destroy( skiplist );

		for( i = 1; i < next; ++i )
		{
			const unsigned int node_count = 1 << (i - 1);
			fprintf(fp, "%u\t%f\n", node_count,
			        time_diff_ns( &stamps[0], &stamps[i] ) / (double)node_count );
		}

		fclose( fp );
	}

#undef MAX_LINKS
#undef INSERTIONS_LOG2
	return 0;
}
Esempio n. 7
0
/**
 * @brief TEST_CASE - Measures lookup trade off between number of elements in the list and number of links per node.
 */
static int link_trade_off_lookup( void )
{
#define MAX_LINKS (SKIPLIST_MAX_LINKS)
#define INSERTIONS_LOG2 (16)
	unsigned int i;
	FILE *fp;
	const char *seperator;

	fp = fopen( "link_trade_off_lookup.gplot", "w" );
	if( !fp ) return -1;
	fprintf(fp, "set term qt\n");
	fprintf(fp, "set key off\n");
	fprintf(fp, "set logscale\n");
	fprintf(fp, "set grid xtics ytics mxtics mytics\n");
	fprintf(fp, "set style textbox opaque noborder\n");
	fprintf(fp, "set title \"Average Lookup Time for Skiplists with Varying Link Counts\"\n");
	fprintf(fp, "set xlabel \"Number of Elements in the Skiplist\"\n");
	fprintf(fp, "set ylabel \"Average Time for One Lookup (ns)\"\n");
	fprintf(fp, "plot " );

	seperator = "";
	for( i = 0; i < MAX_LINKS; ++i )
	{
		fprintf(fp, "%s\"link_trade_off_lookup.dat\" using 1:%u with lines lt -1,"
		        "\"\" using 1:%u:($0*0+%u) with labels center boxed notitle",
		        seperator, i + 2, i + 2, i + 1);
		seperator = ",\\\n\t";
	}
	fprintf(fp, "\n");
	fprintf(fp, "pause -1\n");
	fclose( fp );

	fp = fopen( "link_trade_off_lookup.dat", "w" );
	if( !fp ) return -1;

	for( i = 1; i < (1 << INSERTIONS_LOG2); i <<= 1 )
	{
		unsigned int links;
		fprintf( fp, "%u", i );
		for( links = 1; links <= MAX_LINKS; ++links )
		{
			unsigned int j;
			skiplist_t *skiplist;
			struct timespec start, end;

			skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, links, int_compare, int_fprintf, NULL );
			if( !skiplist ) return -1;

			for( j = 0; j < i; ++j )
				if( skiplist_insert( skiplist, j ) )
					return -1;

			time_stamp( &start );
			for( j = 0; j < i; ++j )
				if( !skiplist_contains( skiplist, j, NULL ) )
					return -1;
			time_stamp( &end );
			fprintf( fp, "\t%f", time_diff_ns( &start, &end ) / (double)i );
			skiplist_destroy( skiplist );
		}
		fprintf( fp, "\n" );
	}

	fclose( fp );

#undef MAX_LINKS
#undef INSERTIONS_LOG2
	return 0;
}
Esempio n. 8
0
/**
 * @brief TEST_CASE - Confirms incorrect inputs are handled gracefully for skiplist_destroy.
 */
static int abuse_skiplist_destroy( void )
{
	/* Can't do much but check NULL doesn't cause a crash. */
	skiplist_destroy( NULL );
	return 0;
}
Esempio n. 9
0
/**
 * @brief TEST_CASE - Sanity test of some key skiplist APIs using a pointer to data items.
 */
static int pointers( void )
{
	skiplist_t *skiplist;
	const coord_t coords[] =
	{
		/* Simple in order insertion. */
		{5,5},
		{7,5},

		/* Duplicate x with increasing y. */
		{5,6},
		{5,8},

		/* Duplicate x with decreasing y. */
		{7,4},
		{7,0},

		/* Decreasing x. */
		{4,5},
		{3,5},

		/* Increasing x. */
		{9,0},
		{10,0},

		/* Duplicate values. */
		{9,0},
		{5,5},

		/* Zero. */
		{0,0},

		/* Huge. */
		{UINT_MAX,UINT_MAX}
	};

	unsigned int i;
	skiplist_node_t *iter;
	coord_t tmp;

	skiplist = skiplist_create( SKIPLIST_PROPERTY_NONE, 8, coord_compare, coord_fprintf, NULL );
	if( !skiplist ) return -1;

	for( i = 0; i < sizeof(coords) / sizeof(coords[0]); ++i )
		if( skiplist_insert( skiplist, (uintptr_t) &coords[i] ) )
			return -1;

	/* Output skiplist for debugging purposes. */
	if( skiplist_fprintf_filename( "pointers.dot", skiplist ) )
		return -1;

	/* Confirm skiplist is in the correct order. */
	tmp.x = 0;
	tmp.y = 0;
	for( iter = skiplist_begin( skiplist ); iter != skiplist_end(); iter = skiplist_next( iter ) )
	{
		coord_t *cur = (coord_t *)skiplist_node_value( iter, NULL );
		if( cur->x < tmp.x ) return -1;
		if( cur->x == tmp.x && cur->y < tmp.y ) return -1;
		tmp = *cur;
	}

	/* Confirm the skiplist contains what we expect. */
	for( i = 0; i < sizeof(coords) / sizeof(coords[0]); ++i )
		if( !skiplist_contains( skiplist, (uintptr_t) &coords[i], NULL ) )
			return -1;

	/* If we use a different pointer to point to the same values the skiplist should skill contain it. */
	tmp = coords[0];
	if( !skiplist_contains( skiplist, (uintptr_t) &tmp, NULL ) )
		return -1;

	/* Free resources. */
	skiplist_destroy( skiplist );

	return 0;
}
Esempio n. 10
0
static int __init skiplist_init(void)
{
	int i;
	struct timeval start, end;
	struct skiplist *list;
	struct skipnode *node;
	int res = 0;

	int *key = kmalloc(N * sizeof(int), GFP_KERNEL);
	if (key == NULL) {
		printk("-ENOMEM\n");
		return -1;
	}

	printk("Starting initialization...\n");
	list = skiplist_create();
        if (list == NULL) {
		printk("-ENOMEM\n");
		return -1;
        }

	printk("Started initialization...\n");
        printk("Test start!\n");

	/* Test 01 */ 
	printk("Test 01: adding and search %d nodes testing!\n", N);
        printk("Add %d nodes...\n", N);

        do_gettimeofday(&start);
        for (i = 0; i < N; i++) {
                int value = key[i] = i;
               	skiplist_insert(list, key[i], value);
        }
        do_gettimeofday(&end);
        printk("time span:% ldms\n", (end.tv_sec - start.tv_sec)*1000 + (end.tv_usec - start.tv_usec)/1000);
#ifdef SKIPLIST_DEBUG
        skiplist_dump(list);
#endif

        /* Search test */
        printk("Now search %d node...\n", N);
        do_gettimeofday(&start);

        for (i = 0; i < N; i++) {
                struct skipnode *node = skiplist_search(list, key[i]);

                if (node != NULL) {
#ifdef SKIPLIST_DEBUG
                        printk("key:%d value:%d\n", node->key, node->value);
#endif
                } else {
                        printk("Not found:%d\n", key[i]);
			res = 1;
			break;
                }
        }
        do_gettimeofday(&end);
        printk("time span:% ldms\n", (end.tv_sec - start.tv_sec)*1000 + (end.tv_usec - start.tv_usec)/1000);
	if (res) {
		printk("Test 01: failed!\n");
		goto out_clean;
	} else {
		printk("Test 01: success!\n");
	}

	/* Test 02 */

	printk("Test 02: search single node (%d/2) testing!\n", N);
	node = skiplist_search(list, N/2);
	if (node && node->value == N/2) {
		printk("Test 02: Success!\n");
	} else {
		printk("Test 02: Failed!\n");
		res = 1;
		goto out_clean;
	}

	/* Test 03 */

	printk("Test 03: remove single node (%d/2) testing!\n", N);
	skiplist_remove(list, N/2);
	node = skiplist_search(list, N/2);
	if (!node) {
		printk("Test 03: Success!\n");
	} else {
		printk("Test 03: Failed (key:%d)!\n", node->key);
		res = 1;
		goto out_clean;
	}

	/* Test 04 */

	printk("Test 04: search single node equal or great than (%d/2) testing!\n", N);
	printk("Test 04: case 1: no equal node (%d/2) \n", N);
	node = skiplist_search_first_eq_big(list, N/2);
	if (!node || node->value != (N/2 + 1)) {
		printk("Test 04: Failed!\n");
		res = 1;
		goto out_clean;
	}

	printk("Test 04: case 2: has equal node (%d/2 + 1) \n", N);
	node = skiplist_search_first_eq_big(list, N/2 + 1);
	if (node && node->value == (N/2 + 1)) {
		printk("Test 04: Success!\n");
	} else {
		printk("Test 04: Failed!\n");
		res = 1;
		goto out_clean;
	}

	/* Test 05 */
	res = 0;
	printk("Test 05: remove all nodes\n");
        for (i = 0; i < N; i++) {
                skiplist_remove(list, key[i]);
        }

        for (i = 0; i < N; i++) {
		node = skiplist_search(list, key[i]);
		if (node) {
			res = 1;
			break;
		}
	}

	if (res)
		printk("Test 05: Failed!\n");
	else
		printk("Test 05: Success!\n");

#ifdef SKIPLIST_DEBUG
        skiplist_dump(list);
#endif

        printk("End of Test.\n");
out_clean:	

        skiplist_destroy(list);

        return 0;
}
Esempio n. 11
0
int main(int argc, char *argv[])
{
    int i;
    int tmp;
    int index1;
    int index2;
    int result;


    log_init();

    if (argc > 1) {
        if (strcasecmp(argv[1], "multi") == 0 || strcmp(argv[1], "1") == 0) {
            skiplist_type = SKIPLIST_TYPE_MULTI;
        }
    }
    printf("skiplist type: %s\n",
            skiplist_type == SKIPLIST_TYPE_FLAT ? "flat" : "multi");

    numbers = (int *)malloc(sizeof(int) * COUNT);
    srand(time(NULL));
    for (i=0; i<COUNT; i++) {
        numbers[i] = i + 1;
    }

    for (i=0; i<COUNT; i++) {
        index1 = LAST_INDEX * (int64_t)rand() / (int64_t)RAND_MAX;
        index2 = LAST_INDEX * (int64_t)rand() / (int64_t)RAND_MAX;
        if (index1 == index2) {
            continue;
        }
        tmp = numbers[index1];
        numbers[index1] = numbers[index2];
        numbers[index2] = tmp;
    }

    fast_mblock_manager_init();
    result = skiplist_init_ex(&sl, LEVEL_COUNT, compare_func,
            free_test_func, MIN_ALLOC_ONCE, skiplist_type);
    if (result != 0) {
        return result;
    }

    test_insert();
    printf("\n");

    fast_mblock_manager_stat_print(false);

    test_delete();
    printf("\n");
    assert(instance_count == 0);

    test_insert();
    printf("\n");

    skiplist_destroy(&sl);
    assert(instance_count == 0);

    test_stable_sort();

    printf("pass OK\n");
    return 0;
}
Esempio n. 12
0
static int test_stable_sort()
{
#define RECORDS 32
    int i;
    int result;
    int index1;
    int index2;
    int delete_count;
    int total_delete_count;
    Skiplist sl;
    SkiplistIterator iterator;
    Record records[RECORDS];
    Record *record;
    Record target;
    void *value;

    instance_count = 0;
    result = skiplist_init_ex(&sl, 12, compare_record,
            free_test_func, 128, skiplist_type);
    if (result != 0) {
        return result;
    }

    for (i=0; i<RECORDS; i++) {
        records[i].line = i + 1;
        records[i].key = i + 1;
    }

    for (i=0; i<RECORDS/4; i++) {
        index1 = (RECORDS - 1) * (int64_t)rand() / (int64_t)RAND_MAX;
        index2 = RECORDS - 1 - index1;
        if (index1 != index2) {
            records[index1].key = records[index2].key;
        }
    }

    for (i=0; i<RECORDS; i++) {
        if ((result=skiplist_insert(&sl, records + i)) != 0) {
            return result;
        }
        instance_count++;
    }
    assert(instance_count == RECORDS);

    for (i=0; i<RECORDS; i++) {
        value = skiplist_find(&sl, records + i);
        assert(value != NULL && ((Record *)value)->key == records[i].key);
    }

    i = 0;
    skiplist_iterator(&sl, &iterator);
    while ((value=skiplist_next(&iterator)) != NULL) {
        i++;
        record = (Record *)value;
        printf("%d => #%d\n", record->key, record->line);
    }
    assert(i==RECORDS);

    target.key = 10;
    target.line = 0;
    if (skiplist_find_all(&sl, &target, &iterator) == 0) {
        printf("found key: %d\n", target.key);
    }
    i = 0;
    while ((value=skiplist_next(&iterator)) != NULL) {
        i++;
        record = (Record *)value;
        printf("%d => #%d\n", record->key, record->line);
    }
    printf("found record count: %d\n", i);

    total_delete_count = 0;
    for (i=0; i<RECORDS; i++) {
        if ((result=skiplist_delete_all(&sl, records + i,
                        &delete_count)) == 0)
        {
            total_delete_count += delete_count;
        }
        assert((result == 0 && delete_count > 0) ||
                (result != 0 && delete_count == 0));
    }
    assert(total_delete_count == RECORDS);
    assert(instance_count == 0);

    i = 0;
    skiplist_iterator(&sl, &iterator);
    while ((value=skiplist_next(&iterator)) != NULL) {
        i++;
    }
    assert(i == 0);

    skiplist_destroy(&sl);
    assert(instance_count == 0);

    return 0;
}
Esempio n. 13
0
int main(int argc, char** argv) {

    if (argc != 2) {
        printf("Usage: %s HPROF_FILE\n", argv[0]);
        exit(1);
    }

    FILE* hprof_fp = fopen(argv[1], "r");
    die(hprof_fp == NULL, "File error");

    hprof_header* header;
    char version[19];
    u4 ident_size;

    int count = fread(version, sizeof(version), 1, hprof_fp);
    die(count != 1, "Unable to read hprof header");

    count = fread(&ident_size, sizeof(u4), 1, hprof_fp);
    die(count != 1, "Unable to read hprof header");

    int success = fseek(hprof_fp, sizeof(u8), SEEK_CUR);
    die(success != 0, "Could not seek forward in the file");

    printf("Header: version=%s identsize=%ju\n",
            version,
            (uintmax_t) be32_to_native(ident_size));

    // For now just reuse it
    hprof_record_header* record_header = calloc(1, sizeof(hprof_record_header));
    hprof_heap_summary* heap_summary = calloc(1, sizeof(hprof_heap_summary));

    // The string table is a skip list that should give us
    // O(n log n) insertion and O(log n) lookup, This is not as 
    // good as a malloc'd array, but does not suffer from the
    // out of order issues that the string id's present us with
    skiplist_t *string_table = malloc(sizeof(skiplist_t));
    skiplist_init(string_table);
    skiplist_set_cmp_fn(string_table, stringtable_cmp);
    skiplist_set_search_fn(string_table, stringtable_search);
    skiplist_set_destroy_fn(string_table, __destroy);

    skiplist_t *class_table = malloc(sizeof(skiplist_t));
    skiplist_init(class_table);
    skiplist_set_cmp_fn(class_table, classtable_cmp);
    skiplist_set_search_fn(class_table, classtable_search);
    skiplist_set_destroy_fn(class_table, __destroy);

    while(1) {
        if (feof(hprof_fp)) {
            break;
        }

        //read_record_header(record_header, hprof_fp);
        funpack(hprof_fp, "bd>d>",
            &record_header->tag,
            &record_header->profiling_ms,
            &record_header->remaining_bytes);

        //printf("Tag=%ju\n", (uintmax_t) record_header->tag);
        switch(record_header->tag) {
            case UTF8:
                //printf("UTF8\n");
                ;
                hprof_utf8 *utf8 = malloc(sizeof(hprof_utf8));
                
                funpack(hprof_fp, "q>", &utf8->id);
                //fread(&utf8->id, sizeof(id), 1, hprof_fp);
                long bytes_remain = record_header->remaining_bytes - sizeof(id);

                // Awesome, hprof strings are utf8, this is good ! the only established
                // C type is char and its a byte wide :D
                utf8->num_chars = bytes_remain / sizeof(char);
                utf8->hprof_offset = ftell(hprof_fp);

                skiplist_insert(string_table, utf8);

                fseek(hprof_fp, bytes_remain, SEEK_CUR);
                break;
            case LOAD_CLASS:
                //printf("LOAD_CLASS\n");
                ;

                hprof_load_class *class = malloc(sizeof(hprof_load_class));
                fread(&class->serial_number, sizeof(u4), 1, hprof_fp);
                class->serial_number = be32_to_native(class->serial_number);
                fseek(hprof_fp, sizeof(id) + sizeof(u4), SEEK_CUR);
                fread(&class->name_id, sizeof(id), 1, hprof_fp);
                class->name_id = be64_to_native(class->name_id);

                skiplist_insert(class_table, class);
                //fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case UNLOAD_CLASS:
                //printf("UNLOAD_CLASS\n");
                fseek(hprof_fp, record_header->remaining_bytes, SEEK_CUR);
                break;
            case FRAME:
                //printf("FRAME\n");
                
                // This is bad !!! If it is slow think about doing two complete passes to 
                // make all the I/O as sequential as possible
                // This implementation is going to jump all over the hprof file

                ;
                long curr_pos = ftell(hprof_fp);
                id ids[4];
                fread(&ids, sizeof(id), 4, hprof_fp);

                u4 class_serial_num;
                fread(&class_serial_num, sizeof(u4), 1, hprof_fp);
                class_serial_num = be32_to_native(class_serial_num);
                hprof_load_class *clazz = (hprof_load_class*) skiplist_search(class_table, &class_serial_num);

                i4 line_num;
                fread(&line_num, sizeof(i4), 1, hprof_fp);
                line_num = be32_to_native(line_num);

                char *method_name = read_string(be64_to_native(ids[1]), string_table, hprof_fp);
                char *method_sig  = read_string(be64_to_native(ids[2]), string_table, hprof_fp);
                char *source_file = read_string(be64_to_native(ids[3]), string_table, hprof_fp);

                char *class_name = "<UNKNOWN_CLASS>";
                if(clazz != NULL) {
                    class_name = read_string(clazz->name_id, string_table, hprof_fp);
                }

                // SOMETIMES NULL
                //printf("%s\n", read_string(ids[3], string_table, hprof_fp));
                
                class_name  = (class_name  == NULL) ? "<UNKNOWN_CLASS>"      : class_name;
                method_name = (method_name == NULL) ? "<UNKNOWN_METHOD>"     : method_name;
                method_sig  = (method_sig  == NULL) ? "<UNKNOWN_METHOD_SIG>" : method_sig;
                source_file = (source_file == NULL) ? "<UNKNOWN_SOURCE>"     : source_file;

                switch(line_num) {
                    case -1:
                        printf("Class %s\n \tMethod=%s\n\tSource=%s @ <UNKNOWN>\n",
                                class_name, method_name, source_file);
                        break;
                    case -2:
                        printf("Class %s\n \tMethod=%s\n\tSource=%s @ <COMPILED_METHOD>\n",
                                class_name, method_name, source_file);
                        break;
                    case -3:
                        printf("Class %s\n \tMethod=%s\n\tSource=%s @ <NATIVE_METHOD>\n",
                                class_name, method_name, source_file);
                        break;
                    default:
                        printf("Class %s\n \tMethod=%s\n\tSource=%s @ %ji\n",
                                class_name, method_name, source_file, (intmax_t) line_num);
                        break;
                }

                break;
            case TRACE:
                //printf("TRACE\n");
                ;
                hprof_stacktrace* stacktrace = calloc(1, sizeof(hprof_stacktrace));

                fread(&stacktrace->serial_number, sizeof(u4), 1, hprof_fp);
                fread(&stacktrace->thread_number, sizeof(u4), 1, hprof_fp);
                fread(&stacktrace->number_frames, sizeof(u4), 1, hprof_fp);

                printf("StackTrace serial_num=%ju "
                       "thread_num=%ju num_frames=%ju\n",
                       (uintmax_t) be64_to_native(stacktrace->serial_number),
                       (uintmax_t) be64_to_native(stacktrace->thread_number),
                       (uintmax_t) be64_to_native(stacktrace->number_frames));

                for (int i=0; i < be32_to_native(stacktrace->number_frames); i++) {
                    id frame_id;
                    fread(&frame_id, sizeof(id), 1, hprof_fp);
                    printf("FrameID=%ju\n", (uintmax_t) be64_to_native(frame_id));
                }

                free(stacktrace);

                break;
            case ALLOC_SITES:
                //printf("ALLOC_SITES\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case HEAP_SUMMARY:
                //printf("HEAP SUMMARY\n");
                fread(&heap_summary->live_bytes, sizeof(u4), 1, hprof_fp);
                fread(&heap_summary->live_instances, sizeof(u4), 1, hprof_fp);
                fread(&heap_summary->allocated_bytes, sizeof(u8), 1, hprof_fp);
                fread(&heap_summary->allocated_instances, sizeof(u8), 1, hprof_fp);
                printf("Heap summary:\n\tReachable bytes=%ju\n\t"
                       "Reachable instances=%ju\n\t"
                       "Allocated bytes=%ju\n\t"
                       "Allocated instances=%ju\n",
                       (uintmax_t) be32_to_native(heap_summary->live_bytes),
                       (uintmax_t) be32_to_native(heap_summary->live_instances),
                       (uintmax_t) be64_to_native(heap_summary->allocated_bytes),
                       (uintmax_t) be64_to_native(heap_summary->allocated_instances));
                break;
            case START_THREAD:
                //printf("START_THREAD\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case END_THREAD:
                //printf("END_THREAD\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case HEAP_DUMP:
                //printf("HEAP_DUMP\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case CPU_SAMPLES:
                //printf("CPU_SAMPLES\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case CONTROL_SETTINGS:
                //printf("CONTROL_SETTINGS\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case HEAP_DUMP_SEGMENT:
                //printf("HEAP_DUMP_SEGMENT\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                break;
            case HEAP_DUMP_END:
                //printf("HEAP_DUMP_END\n");
                fseek(hprof_fp, be32_to_native(record_header->remaining_bytes), SEEK_CUR);
                exit(1);
                break;
            default:
                printf("BANG\n");
                exit(1);
                break;
        }

        //printf("%lu\n", ftell(hprof_fp));
    }

    skiplist_destroy(string_table);
    free(string_table);

    skiplist_destroy(class_table);
    free(class_table);

    fclose(hprof_fp);
    return 0;
}