diff --git a/Assembly.cpp b/Assembly.cpp
index 407ee32..7c1b527 100644
--- a/Assembly.cpp
+++ b/Assembly.cpp
@@ -9,7 +9,7 @@
 #include "POA.h"
 #include "Correct.h"
 #include "Output.h"
-#include "Trio.h"
+#include "yak.h"
 
 Total_Count_Table TCB;
 Total_Pos_Table PCB;
diff --git a/Assembly.h b/Assembly.h
index 557aa8a..81e1104 100644
--- a/Assembly.h
+++ b/Assembly.h
@@ -8,6 +8,7 @@
 #define Get_Cigar_Type(RECORD) (RECORD&3)
 #define Get_Cigar_Length(RECORD) (RECORD>>2)
 
+void ha_count_high(const hifiasm_opt_t *asm_opt);
 void Counting_multiple_thr();
 void Build_hash_table_multiple_thr();
 void Overlap_calculate_multipe_thr();
diff --git a/CommandLines.cpp b/CommandLines.cpp
index ac424e6..da2e587 100644
--- a/CommandLines.cpp
+++ b/CommandLines.cpp
@@ -28,6 +28,7 @@ void Print_H(hifiasm_opt_t* asm_opt)
     fprintf(stderr, "    -r INT        round of correction [%d]\n", asm_opt->number_of_round);
     fprintf(stderr, "    -a INT        round of assembly cleaning [%d]\n", asm_opt->clean_round);
     fprintf(stderr, "    -k INT        k-mer length [%d] (must be < 64)\n", asm_opt->k_mer_length);
+	fprintf(stderr, "    -f INT        number of bits for bloom filter [%d]\n", asm_opt->bf_shift);
     ///fprintf(stderr, "    -w            write all overlaps to disk, can accelerate assembly next time [%d]\n", asm_opt->write_index_to_disk);
     ///fprintf(stderr, "    -l            load all overlaps from disk, can avoid overlap calculation [%d]\n", asm_opt->load_index_from_disk);
     ///fprintf(stderr, "    -i            ignore saved overlaps in *.ovlp*.bin files\n");
@@ -63,7 +64,8 @@ void init_opt(hifiasm_opt_t* asm_opt)
     asm_opt->pat_index = NULL;
     asm_opt->mat_index = NULL;
     asm_opt->thread_num = 1;
-    asm_opt->k_mer_length = 39;
+    asm_opt->k_mer_length = 41;
+	asm_opt->bf_shift = 37;
     asm_opt->k_mer_min_freq = 3;
     asm_opt->k_mer_max_freq = 66;
     asm_opt->load_index_from_disk = 1;
@@ -295,7 +297,7 @@ int CommandLine_process(int argc, char *argv[], hifiasm_opt_t* asm_opt)
 
     int c;
 
-    while ((c = ketopt(&opt, argc, argv, 1, "hvt:o:k:lwm:n:r:a:b:z:x:y:p:c:d:M:P:i", 0)) >= 0) {
+    while ((c = ketopt(&opt, argc, argv, 1, "hvt:o:k:lwm:n:r:a:b:z:x:y:p:c:d:M:P:if:", 0)) >= 0) {
         if (c == 'h')
         {
             Print_H(asm_opt);
@@ -305,7 +307,8 @@ int CommandLine_process(int argc, char *argv[], hifiasm_opt_t* asm_opt)
         {
             fprintf(stderr, "[Version] %s\n", VERSION);
             return 0;
-        } 
+        }
+		else if (c == 'f') asm_opt->bf_shift = atoi(opt.arg);
         else if (c == 't') asm_opt->thread_num = atoi(opt.arg); 
         else if (c == 'o') asm_opt->output_file_name = opt.arg;
         else if (c == 'r') asm_opt->number_of_round = atoi(opt.arg);
diff --git a/CommandLines.h b/CommandLines.h
index 7279cdb..b3f7f28 100644
--- a/CommandLines.h
+++ b/CommandLines.h
@@ -15,6 +15,7 @@ typedef struct {
     char* mat_index;
     int thread_num;
     int k_mer_length;
+	int bf_shift;
     int k_mer_min_freq;
     int k_mer_max_freq;
     int load_index_from_disk;
@@ -52,4 +53,4 @@ void clear_opt(hifiasm_opt_t* asm_opt, int last_round);
 int CommandLine_process (int argc, char *argv[], hifiasm_opt_t* asm_opt);
 double Get_T(void);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/Hash_Table.h b/Hash_Table.h
index 458312d..c4ae1c8 100644
--- a/Hash_Table.h
+++ b/Hash_Table.h
@@ -2,6 +2,7 @@
 #define __HASHTABLE__
 #include "khashl.h"
 #include "kmer.h"
+#include "yak.h"
 
 KHASHL_MAP_INIT(static inline, Count_Table, ha_ct, uint64_t, int, kh_hash_dummy, kh_eq_generic)
 KHASHL_MAP_INIT(static inline, Pos_Table, ha_pt, uint64_t, uint64_t, kh_hash_dummy, kh_eq_generic)
diff --git a/Makefile b/Makefile
index 4d00034..89b9d53 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,8 @@ CXXFLAGS=	-g -O3 -msse4.2 -mpopcnt -fomit-frame-pointer -Wall
 CPPFLAGS=
 INCLUDES=
 OBJS=		Output.o CommandLines.o Process_Read.o Assembly.o Hash_Table.o \
-			POA.o Correct.o Levenshtein_distance.o Overlaps.o Trio.o kthread.o
+			POA.o Correct.o Levenshtein_distance.o Overlaps.o Trio.o kthread.o \
+			yak-bbf.o yak-count.o yak-sys.o
 EXE=		hifiasm
 LIBS=		-lz -lpthread -lm
 
@@ -32,25 +33,28 @@ depend:
 # DO NOT DELETE
 
 Assembly.o: Assembly.h CommandLines.h Process_Read.h kseq.h Overlaps.h kvec.h
-Assembly.o: kdq.h kmer.h Hash_Table.h khashl.h POA.h Correct.h
-Assembly.o: Levenshtein_distance.h Output.h Trio.h
+Assembly.o: kdq.h kmer.h Hash_Table.h khashl.h yak.h POA.h Correct.h
+Assembly.o: Levenshtein_distance.h Output.h
 CommandLines.o: CommandLines.h ketopt.h
 Correct.o: Correct.h Hash_Table.h khashl.h kmer.h Process_Read.h kseq.h
-Correct.o: Overlaps.h kvec.h kdq.h CommandLines.h Levenshtein_distance.h
-Correct.o: POA.h Assembly.h
+Correct.o: Overlaps.h kvec.h kdq.h CommandLines.h yak.h
+Correct.o: Levenshtein_distance.h POA.h Assembly.h
 Hash_Table.o: Hash_Table.h khashl.h kmer.h Process_Read.h kseq.h Overlaps.h
-Hash_Table.o: kvec.h kdq.h CommandLines.h Correct.h Levenshtein_distance.h
-Hash_Table.o: POA.h ksort.h
+Hash_Table.o: kvec.h kdq.h CommandLines.h yak.h Correct.h
+Hash_Table.o: Levenshtein_distance.h POA.h ksort.h
 Levenshtein_distance.o: Levenshtein_distance.h
 Output.o: Output.h CommandLines.h
 Overlaps.o: Overlaps.h kvec.h kdq.h ksort.h Process_Read.h kseq.h
-Overlaps.o: CommandLines.h Hash_Table.h khashl.h kmer.h Correct.h
+Overlaps.o: CommandLines.h Hash_Table.h khashl.h kmer.h yak.h Correct.h
 Overlaps.o: Levenshtein_distance.h POA.h
 POA.o: POA.h Hash_Table.h khashl.h kmer.h Process_Read.h kseq.h Overlaps.h
-POA.o: kvec.h kdq.h CommandLines.h Correct.h Levenshtein_distance.h
+POA.o: kvec.h kdq.h CommandLines.h yak.h Correct.h Levenshtein_distance.h
 Process_Read.o: Process_Read.h kseq.h Overlaps.h kvec.h kdq.h CommandLines.h
 Trio.o: khashl.h kthread.h Process_Read.h kseq.h Overlaps.h kvec.h kdq.h
-Trio.o: CommandLines.h Trio.h kmer.h
+Trio.o: CommandLines.h yak.h
 kthread.o: kthread.h
 main.o: CommandLines.h Process_Read.h kseq.h Overlaps.h kvec.h kdq.h
 main.o: Assembly.h Levenshtein_distance.h
+yak-bbf.o: yak.h
+yak-count.o: CommandLines.h yak.h khashl.h kthread.h kseq.h
+yak-sys.o: yak.h
diff --git a/Overlaps.cpp b/Overlaps.cpp
index 72ab35e..fbd01d6 100644
--- a/Overlaps.cpp
+++ b/Overlaps.cpp
@@ -46,9 +46,6 @@ void ma_hit_sort_qns(ma_hit_t *a, long long n)
 	radix_sort_hit_qns(a, a + n);
 }
 
-
-
-
 asg_t *asg_init(void)
 {
 	return (asg_t*)calloc(1, sizeof(asg_t));
diff --git a/Trio.cpp b/Trio.cpp
index 4bf4b8b..ff2f7eb 100644
--- a/Trio.cpp
+++ b/Trio.cpp
@@ -6,45 +6,35 @@
 #include "khashl.h" // hash table
 #include "kthread.h"
 #include "Process_Read.h"
-#include "Trio.h"
+#include "yak.h"
 #include "CommandLines.h"
-#include "kmer.h"
 
-#define CALLOC(ptr, len) ((ptr) = (__typeof__(ptr))calloc((len), sizeof(*(ptr))))
-#define MALLOC(ptr, len) ((ptr) = (__typeof__(ptr))malloc((len) * sizeof(*(ptr))))
-#define REALLOC(ptr, len) ((ptr) = (__typeof__(ptr))realloc((ptr), (len) * sizeof(*(ptr))))
+#define YAK_MAX_KMER     31
+#define YAK_COUNTER_BITS 10
+#define YAK_N_COUNTS     (1<<YAK_COUNTER_BITS)
+#define YAK_MAX_COUNT    ((1<<YAK_COUNTER_BITS)-1)
+
+#define YAK_LOAD_ALL       1
+#define YAK_LOAD_TRIOBIN1  2
+#define YAK_LOAD_TRIOBIN2  3
+
+#define YAK_MAGIC "YAK\2"
+
 #define yak_ch_eq(a, b) ((a)>>YAK_COUNTER_BITS == (b)>>YAK_COUNTER_BITS) // lower 8 bits for counts; higher bits for k-mer
 #define yak_ch_hash(a) ((a)>>YAK_COUNTER_BITS)
-KHASHL_SET_INIT(, yak_ht_t, yak_ht, uint64_t, yak_ch_hash, yak_ch_eq)
+KHASHL_SET_INIT(static klib_unused, yak_ht_t, yak_ht, uint64_t, yak_ch_hash, yak_ch_eq)
 
-///#define CHUNK_SIZE 200000
+typedef struct {
+	struct yak_ht_t *h;
+} yak_ch1_t;
 
-unsigned char seq_nt4_table[256] = { // translate ACGT to 0123
-	0, 1, 2, 3,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 0, 4, 1,  4, 4, 4, 2,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  3, 3, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 0, 4, 1,  4, 4, 4, 2,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  3, 3, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
-	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4
-};
+typedef struct {
+	int k, pre, n_hash, n_shift;
+	uint64_t tot;
+	yak_ch1_t *h;
+} yak_ch_t;
 
-static inline uint64_t yak_hash_long(uint64_t x[4])
-{
-	int j = x[1] < x[3]? 0 : 1;
-	return yak_hash64_64(x[j<<1|0]) + yak_hash64_64(x[j<<1|1]);
-}
-
-int yak_ch_get(const yak_ch_t *h, uint64_t x)
+static int yak_ch_get(const yak_ch_t *h, uint64_t x)
 {
 	int mask = (1<<h->pre) - 1;
 	yak_ht_t *g = h->h[x&mask].h;
@@ -53,21 +43,7 @@ int yak_ch_get(const yak_ch_t *h, uint64_t x)
 	return k == kh_end(g)? -1 : kh_key(g, k)&YAK_MAX_COUNT;
 }
 
-yak_bf_t *yak_bf_init(int n_shift, int n_hashes)
-{
-	yak_bf_t *b;
-	void *ptr = 0;
-	if (n_shift + YAK_BLK_SHIFT > 64 || n_shift < YAK_BLK_SHIFT) return 0;
-	b = (yak_bf_t*)calloc(1, sizeof(yak_bf_t));
-	b->n_shift = n_shift;
-	b->n_hashes = n_hashes;
-	posix_memalign(&ptr, 1<<(YAK_BLK_SHIFT-3), 1ULL<<(n_shift-3));
-	b->b = (uint8_t*)ptr;
-	bzero(b->b, 1ULL<<(n_shift-3));
-	return b;
-}
-
-yak_ch_t *yak_ch_init(int k, int pre, int n_hash, int n_shift)
+static yak_ch_t *yak_ch_init(int k, int pre)
 {
 	yak_ch_t *h;
 	int i;
@@ -77,32 +53,10 @@ yak_ch_t *yak_ch_init(int k, int pre, int n_hash, int n_shift)
 	CALLOC(h->h, 1<<h->pre);
 	for (i = 0; i < 1<<h->pre; ++i)
 		h->h[i].h = yak_ht_init();
-	if (n_hash > 0 && n_shift > h->pre) {
-		h->n_hash = n_hash, h->n_shift = n_shift;
-		for (i = 0; i < 1<<h->pre; ++i)
-			h->h[i].b = yak_bf_init(h->n_shift - h->pre, h->n_hash);
-	}
 	return h;
 }
 
-void yak_bf_destroy(yak_bf_t *b)
-{
-	if (b == 0) return;
-	free(b->b); free(b);
-}
-
-void yak_ch_destroy_bf(yak_ch_t *h)
-{
-	int i;
-	for (i = 0; i < 1<<h->pre; ++i) {
-		if (h->h[i].b)
-			yak_bf_destroy(h->h[i].b);
-		h->h[i].b = 0;
-	}
-}
-
-
-yak_ch_t *yak_ch_restore_core(yak_ch_t *ch0, const char *fn, int mode, ...)
+static yak_ch_t *yak_ch_restore_core(yak_ch_t *ch0, const char *fn, int mode, ...)
 {
 	va_list ap;
 	FILE *fp;
@@ -138,7 +92,7 @@ yak_ch_t *yak_ch_restore_core(yak_ch_t *ch0, const char *fn, int mode, ...)
 		return 0;
 	}
 
-	ch = ch0 == 0? yak_ch_init(t[0], t[1], 0, 0) : ch0;
+	ch = ch0 == 0? yak_ch_init(t[0], t[1]) : ch0;
 	assert((int)t[0] == ch->k && (int)t[1] == ch->pre);
 	for (i = 0; i < 1<<ch->pre; ++i) {
 		yak_ht_t *h = ch->h[i].h;
@@ -172,17 +126,39 @@ yak_ch_t *yak_ch_restore_core(yak_ch_t *ch0, const char *fn, int mode, ...)
 	return ch;
 }
 
-
-void yak_ch_destroy(yak_ch_t *h)
+static void yak_ch_destroy(yak_ch_t *h)
 {
 	int i;
 	if (h == 0) return;
-	yak_ch_destroy_bf(h);
 	for (i = 0; i < 1<<h->pre; ++i)
 		yak_ht_destroy(h->h[i].h);
 	free(h->h); free(h);
 }
 
+typedef struct {
+	int max;
+	uint32_t *s;
+} tb_buf_t;
+
+typedef struct {
+	int k, n_threads, print_diff;
+	double ratio_thres;
+	const yak_ch_t *ch;
+	tb_buf_t *buf;
+	UC_Read *bseq;
+	All_reads* seq; 
+} tb_shared_t;
+
+typedef struct {
+	int c[16];
+	int sc[2];
+	int nk;
+} tb_cnt_t;
+
+typedef struct {
+	int n_seq;
+	tb_shared_t *aux;
+} tb_step_t;
 
 static char tb_classify(const int sc[2], const int *c, int k, double ratio_thres)
 {
@@ -206,8 +182,6 @@ static char tb_classify(const int sc[2], const int *c, int k, double ratio_thres
 
 static void tb_worker(void *_data, long k, int tid)
 {
-	///tb_step_t *t = (tb_step_t*)_data;
-	///tb_shared_t *aux = t->aux;
 	tb_shared_t *aux = (tb_shared_t*)_data;
 	UC_Read *s = &aux->bseq[tid]; 
 	recover_UC_Read(s, aux->seq, k);
@@ -243,12 +217,7 @@ static void tb_worker(void *_data, long k, int tid)
 			if (++l >= aux->k) {
 				int type = 0, c1, c2;
 				uint64_t y;
-
-
-				//++t->cnt[k].nk;
 				++cnt.nk;
-
-
 				if (aux->ch->k < 32)
 					y = yak_hash64(x[0] < x[1]? x[0] : x[1], mask);
 				else
@@ -259,28 +228,18 @@ static void tb_worker(void *_data, long k, int tid)
 				if (c1 == 2 && c2 == 0) type = 1;
 				else if (c2 == 2 && c1 == 0) type = 2;
 				b->s[i] = type;
-
-
-				///++t->cnt[k].c[flag];
 				++cnt.c[flag];
-
-				// if (aux->print_diff && (flag>>2&3) != (flag&3))
-				// 	printf("D\t%s\t%d\t%d\t%d\n", s->name, i, flag&3, flag>>2&3);
 			}
 		} else l = 0, x[0] = x[1] = x[2] = x[3] = 0;
 	}
 	for (l = 0, i = 1; i <= s->length; ++i) {
 		if (i == s->length || b->s[i] != b->s[l]) {
 			if (b->s[l] > 0 && i - l >= aux->k - 4)
-			{
-				///t->cnt[k].sc[b->s[l] - 1] += i - l;
 				cnt.sc[b->s[l] - 1] += i - l;
-			}
 			l = i;
 		}
 	}
 
-
 	int *c = cnt.c;
 	char type;
 	type = tb_classify(cnt.sc, c, aux->k, aux->ratio_thres);
@@ -289,12 +248,9 @@ static void tb_worker(void *_data, long k, int tid)
 	if(type == 'm') aux->seq->trio_flag[k] = MOTHER;
 }
 
-
-
-void trio_partition()
+void trio_partition(void)
 {
-    if(asm_opt.pat_index == NULL || asm_opt.mat_index == NULL)
-	{
+    if (asm_opt.pat_index == NULL || asm_opt.mat_index == NULL) {
 		memset(R_INF.trio_flag, AMBIGU, R_INF.total_reads*sizeof(uint8_t));
 		return;
 	}
@@ -303,32 +259,26 @@ void trio_partition()
 	fprintf(stderr, "Start trio binning ...... \n");
 
     yak_ch_t *ch;
-    int i/**, min_cnt = 2, mid_cnt = 5**/;
+    int i /**, min_cnt = 2, mid_cnt = 5**/;
     tb_shared_t aux;
     memset(&aux, 0, sizeof(tb_shared_t));
 	aux.n_threads = asm_opt.thread_num, aux.print_diff = 0;
 	aux.ratio_thres = 0.33;
 	aux.seq = &R_INF;
 
-
     ch = yak_ch_restore_core(0,  asm_opt.pat_index, YAK_LOAD_TRIOBIN1, asm_opt.min_cnt, asm_opt.mid_cnt);
 	ch = yak_ch_restore_core(ch, asm_opt.mat_index, YAK_LOAD_TRIOBIN2, asm_opt.min_cnt, asm_opt.mid_cnt);
 
-
-
     aux.k = ch->k;
     aux.ch = ch;
 	aux.buf = (tb_buf_t*)calloc(aux.n_threads, sizeof(tb_buf_t));
 	aux.bseq = (UC_Read*)calloc(aux.n_threads, sizeof(UC_Read));
 	for (i = 0; i < aux.n_threads; ++i)
-	{
 		init_UC_Read(&aux.bseq[i]);
-	} 
 	
 	kt_for(aux.n_threads, tb_worker, &aux, aux.seq->total_reads);
 	
-    for (i = 0; i < aux.n_threads; ++i)
-	{
+    for (i = 0; i < aux.n_threads; ++i) {
 		free(aux.buf[i].s);
 		destory_UC_Read(&aux.bseq[i]);
 	} 
diff --git a/Trio.h b/Trio.h
deleted file mode 100644
index d5319f5..0000000
--- a/Trio.h
+++ /dev/null
@@ -1,71 +0,0 @@
-#ifndef __TRIO__
-#define __TRIO__
-#include <stdint.h>
-
-#define YAK_MAX_KMER     31
-#define YAK_COUNTER_BITS 10
-#define YAK_N_COUNTS     (1<<YAK_COUNTER_BITS)
-#define YAK_MAX_COUNT    ((1<<YAK_COUNTER_BITS)-1)
-
-#define YAK_BLK_SHIFT  9 // 64 bytes, the size of a cache line
-#define YAK_BLK_MASK   ((1<<(YAK_BLK_SHIFT)) - 1)
-
-#define YAK_LOAD_ALL       1
-#define YAK_LOAD_TRIOBIN1  2
-#define YAK_LOAD_TRIOBIN2  3
-
-#define YAK_MAGIC "YAK\2"
-
-typedef struct {
-	int n_shift, n_hashes;
-	uint8_t *b;
-} yak_bf_t;
-
-struct yak_ht_t;
-
-typedef struct {
-	struct yak_ht_t *h;
-	yak_bf_t *b;
-} yak_ch1_t;
-
-typedef struct {
-	int k, pre, n_hash, n_shift;
-	uint64_t tot;
-	yak_ch1_t *h;
-} yak_ch_t;
-
-
-typedef struct {
-	int max;
-	uint32_t *s;
-} tb_buf_t;
-
-
-typedef struct {
-	int k, n_threads, print_diff;
-	double ratio_thres;
-	///bseq_file_t *fp;
-	const yak_ch_t *ch;
-	tb_buf_t *buf;
-	UC_Read *bseq;
-	All_reads* seq; 
-} tb_shared_t;
-
-typedef struct {
-	int c[16];
-	int sc[2];
-	int nk;
-} tb_cnt_t;
-
-
-typedef struct {
-	int n_seq;
-	tb_shared_t *aux;
-	///bseq1_t *seq;
-	///All_reads* seq;
-	///tb_cnt_t *cnt;
-} tb_step_t;
-
-
-void trio_partition();
-#endif
\ No newline at end of file
diff --git a/kmer.h b/kmer.h
index fad4ac2..a06c822 100644
--- a/kmer.h
+++ b/kmer.h
@@ -78,45 +78,4 @@ inline void k_mer_append(Hash_code* code, uint64_t c, int k)
 	code->x[3] = code->x[3] >> 1 | (uint64_t)(1 - (c>>1)) << shift;
 }
 
-static inline uint64_t yak_hash64(uint64_t key, uint64_t mask) // invertible integer hash function
-{
-	key = (~key + (key << 21)) & mask; // key = (key << 21) - key - 1;
-	key = key ^ key >> 24;
-	key = ((key + (key << 3)) + (key << 8)) & mask; // key * 265
-	key = key ^ key >> 14;
-	key = ((key + (key << 2)) + (key << 4)) & mask; // key * 21
-	key = key ^ key >> 28;
-	key = (key + (key << 31)) & mask;
-	return key;
-}
-
-static inline uint64_t yak_hash64_64(uint64_t key)
-{
-	key = ~key + (key << 21);
-	key = key ^ key >> 24;
-	key = (key + (key << 3)) + (key << 8);
-	key = key ^ key >> 14;
-	key = (key + (key << 2)) + (key << 4);
-	key = key ^ key >> 28;
-	key = key + (key << 31);
-	return key;
-}
-
-inline void Hashcode_to_string(Hash_code* code, char* str, int k) // FIXME: not working
-{
-    uint8_t c;
-    int i;
-    for (i = 0; i < k; i++)
-    {
-        c = (code->x[1] >> (k - i - 1)) & ((uint64_t)1);
-        c = c << 1;
-        c = c | ((code->x[0] >> (k - i - 1)) & ((uint64_t)1));
-
-        str[i] = s_H[c];
-    }
-    
-}
-
-void init_HPC_seq(HPC_seq* seq, char* str, long long l);
-
 #endif
diff --git a/main.cpp b/main.cpp
index 76fcfd8..c666d00 100644
--- a/main.cpp
+++ b/main.cpp
@@ -4,16 +4,26 @@
 #include "Process_Read.h"
 #include "Assembly.h"
 #include "Levenshtein_distance.h"
+#include "yak.h"
 
 int main(int argc, char *argv[])
 {
+	int i;
+
     init_opt(&asm_opt);
 
     if (!CommandLine_process(argc, argv, &asm_opt)) return 1;
 
-    Correct_Reads(asm_opt.number_of_round);
-
+	yak_reset_realtime();
+	ha_count_high(&asm_opt);
+	if (0) {
+	    Correct_Reads(asm_opt.number_of_round);
+	}
     destory_opt(&asm_opt);
-    
+	fprintf(stderr, "[M::%s] Version: %s\n", __func__, "dummy");
+	fprintf(stderr, "[M::%s] CMD:", __func__);
+	for (i = 0; i < argc; ++i)
+		fprintf(stderr, " %s", argv[i]);
+	fprintf(stderr, "\n[M::%s] Real time: %.3f sec; CPU: %.3f sec; Peak RSS: %.3f GB\n", __func__, yak_realtime(), yak_cputime(), yak_peakrss() / 1024.0 / 1024.0 / 1024.0);
     return 0;
 }
diff --git a/yak-bbf.cpp b/yak-bbf.cpp
new file mode 100644
index 0000000..742b80a
--- /dev/null
+++ b/yak-bbf.cpp
@@ -0,0 +1,42 @@
+#include <stdlib.h>
+#include <string.h>
+#include "yak.h"
+
+yak_bf_t *yak_bf_init(int n_shift, int n_hashes)
+{
+	yak_bf_t *b;
+	void *ptr = 0;
+	if (n_shift + YAK_BLK_SHIFT > 64 || n_shift < YAK_BLK_SHIFT) return 0;
+	CALLOC(b, 1);
+	b->n_shift = n_shift;
+	b->n_hashes = n_hashes;
+	posix_memalign(&ptr, 1<<(YAK_BLK_SHIFT-3), 1ULL<<(n_shift-3));
+	b->b = (uint8_t*)ptr;
+	bzero(b->b, 1ULL<<(n_shift-3));
+	return b;
+}
+
+void yak_bf_destroy(yak_bf_t *b)
+{
+	if (b == 0) return;
+	free(b->b); free(b);
+}
+
+int yak_bf_insert(yak_bf_t *b, uint64_t hash)
+{
+	int x = b->n_shift - YAK_BLK_SHIFT;
+	uint64_t y = hash & ((1ULL<<x) - 1);
+	int h1 = hash >> x & YAK_BLK_MASK;
+	int h2 = hash >> b->n_shift & YAK_BLK_MASK;
+	uint8_t *p = &b->b[y<<(YAK_BLK_SHIFT-3)];
+	int i, z = h1, cnt = 0;
+	if ((h2&31) == 0) h2 = (h2 + 1) & YAK_BLK_MASK; // otherwise we may repeatedly use a few bits
+	for (i = 0; i < b->n_hashes; z = (z + h2) & YAK_BLK_MASK) {
+		uint8_t *q = &p[z>>3], u;
+		u = 1<<(z&7);
+		cnt += !!(*q & u);
+		*q |= u;
+		++i;
+	}
+	return cnt;
+}
diff --git a/yak-count.cpp b/yak-count.cpp
new file mode 100644
index 0000000..3dead7b
--- /dev/null
+++ b/yak-count.cpp
@@ -0,0 +1,383 @@
+#include <stdint.h>
+#include "CommandLines.h"
+#include "yak.h"
+#include "khashl.h"
+
+#define YAK_COUNTER_BITS 10
+#define YAK_N_COUNTS     (1<<YAK_COUNTER_BITS)
+#define YAK_MAX_COUNT    ((1<<YAK_COUNTER_BITS)-1)
+
+#define yak_ch_eq(a, b) ((a)>>YAK_COUNTER_BITS == (b)>>YAK_COUNTER_BITS) // lower 8 bits for counts; higher bits for k-mer
+#define yak_ch_hash(a) ((a)>>YAK_COUNTER_BITS)
+KHASHL_SET_INIT(static klib_unused, yak_ht_t, yak_ht, uint64_t, yak_ch_hash, yak_ch_eq)
+
+typedef struct {
+	int32_t bf_shift, bf_n_hash;
+	int32_t k;
+	int32_t pre;
+	int32_t n_thread;
+	int64_t chunk_size;
+} yak_copt_t;
+
+typedef struct {
+	yak_ht_t *h;
+	yak_bf_t *b;
+} yak_ch1_t;
+
+typedef struct {
+	int k, pre, n_hash, n_shift;
+	uint64_t tot;
+	yak_ch1_t *h;
+} yak_ch_t;
+
+const unsigned char seq_nt4_table[256] = { // translate ACGT to 0123
+	0, 1, 2, 3,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 0, 4, 1,  4, 4, 4, 2,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  3, 3, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 0, 4, 1,  4, 4, 4, 2,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  3, 3, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,
+	4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4,  4, 4, 4, 4
+};
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "kthread.h"
+
+/*** hash table ***/
+
+static yak_ch_t *yak_ch_init(int k, int pre, int n_hash, int n_shift)
+{
+	yak_ch_t *h;
+	int i;
+	if (pre < YAK_COUNTER_BITS) return 0;
+	CALLOC(h, 1);
+	h->k = k, h->pre = pre;
+	CALLOC(h->h, 1<<h->pre);
+	for (i = 0; i < 1<<h->pre; ++i)
+		h->h[i].h = yak_ht_init();
+	if (n_hash > 0 && n_shift > h->pre) {
+		h->n_hash = n_hash, h->n_shift = n_shift;
+		for (i = 0; i < 1<<h->pre; ++i)
+			h->h[i].b = yak_bf_init(h->n_shift - h->pre, h->n_hash);
+	}
+	return h;
+}
+
+static void yak_ch_destroy_bf(yak_ch_t *h)
+{
+	int i;
+	for (i = 0; i < 1<<h->pre; ++i) {
+		if (h->h[i].b)
+			yak_bf_destroy(h->h[i].b);
+		h->h[i].b = 0;
+	}
+}
+
+static void yak_ch_destroy(yak_ch_t *h)
+{
+	int i;
+	if (h == 0) return;
+	yak_ch_destroy_bf(h);
+	for (i = 0; i < 1<<h->pre; ++i)
+		yak_ht_destroy(h->h[i].h);
+	free(h->h); free(h);
+}
+
+static int yak_ch_insert_list(yak_ch_t *h, int create_new, int n, const uint64_t *a)
+{
+	int j, mask = (1<<h->pre) - 1, n_ins = 0;
+	yak_ch1_t *g;
+	if (n == 0) return 0;
+	g = &h->h[a[0]&mask];
+	for (j = 0; j < n; ++j) {
+		int ins = 1, absent;
+		uint64_t x = a[j] >> h->pre;
+		khint_t k;
+		if ((a[j]&mask) != (a[0]&mask)) continue;
+		if (create_new) {
+			if (g->b)
+				ins = (yak_bf_insert(g->b, x) == h->n_hash);
+			if (ins) {
+				k = yak_ht_put(g->h, x<<YAK_COUNTER_BITS, &absent);
+				if (absent) ++n_ins;
+				if ((kh_key(g->h, k)&YAK_MAX_COUNT) < YAK_MAX_COUNT)
+					++kh_key(g->h, k);
+			}
+		} else {
+			k = yak_ht_get(g->h, x<<YAK_COUNTER_BITS);
+			if (k != kh_end(g->h) && (kh_key(g->h, k)&YAK_MAX_COUNT) < YAK_MAX_COUNT)
+				++kh_key(g->h, k);
+		}
+	}
+	return n_ins;
+}
+
+static int yak_ch_get(const yak_ch_t *h, uint64_t x)
+{
+	int mask = (1<<h->pre) - 1;
+	yak_ht_t *g = h->h[x&mask].h;
+	khint_t k;
+	k = yak_ht_get(g, x >> h->pre << YAK_COUNTER_BITS);
+	return k == kh_end(g)? -1 : kh_key(g, k)&YAK_MAX_COUNT;
+}
+
+/*** generate histogram ***/
+
+typedef struct {
+	uint64_t c[YAK_N_COUNTS];
+} buf_cnt_t;
+
+typedef struct {
+	const yak_ch_t *h;
+	buf_cnt_t *cnt;
+} hist_aux_t;
+
+static void worker_hist(void *data, long i, int tid) // callback for kt_for()
+{
+	hist_aux_t *a = (hist_aux_t*)data;
+	uint64_t *cnt = a->cnt[tid].c;
+	yak_ht_t *g = a->h->h[i].h;
+	khint_t k;
+	for (k = 0; k < kh_end(g); ++k)
+		if (kh_exist(g, k))
+			++cnt[kh_key(g, k)&YAK_MAX_COUNT];
+}
+
+static void yak_ch_hist(const yak_ch_t *h, int64_t cnt[YAK_N_COUNTS], int n_thread)
+{
+	hist_aux_t a;
+	int i, j;
+	a.h = h;
+	memset(cnt, 0, YAK_N_COUNTS * sizeof(uint64_t));
+	CALLOC(a.cnt, n_thread);
+	kt_for(n_thread, worker_hist, &a, 1<<h->pre);
+	for (i = 0; i < YAK_N_COUNTS; ++i) cnt[i] = 0;
+	for (j = 0; j < n_thread; ++j)
+		for (i = 0; i < YAK_N_COUNTS; ++i)
+			cnt[i] += a.cnt[j].c[i];
+	free(a.cnt);
+}
+
+/*** shrink a hash table ***/
+
+typedef struct {
+	int min, max;
+	yak_ch_t *h;
+} shrink_aux_t;
+
+static void worker_shrink(void *data, long i, int tid) // callback for kt_for()
+{
+	shrink_aux_t *a = (shrink_aux_t*)data;
+	yak_ch_t *h = a->h;
+	yak_ht_t *g = h->h[i].h, *f;
+	khint_t k;
+	f = yak_ht_init();
+	yak_ht_resize(f, kh_size(g));
+	for (k = 0; k < kh_end(g); ++k) {
+		if (kh_exist(g, k)) {
+			int absent, c = kh_key(g, k) & YAK_MAX_COUNT;
+			if (c >= a->min && c <= a->max)
+				yak_ht_put(f, kh_key(g, k), &absent);
+		}
+	}
+	yak_ht_destroy(g);
+	h->h[i].h = f;
+}
+
+static void yak_ch_shrink(yak_ch_t *h, int min, int max, int n_thread)
+{
+	int i;
+	shrink_aux_t a;
+	a.h = h, a.min = min, a.max = max;
+	kt_for(n_thread, worker_shrink, &a, 1<<h->pre);
+	for (i = 0, h->tot = 0; i < 1<<h->pre; ++i)
+		h->tot += kh_size(h->h[i].h);
+}
+
+#include <zlib.h>
+#include <string.h>
+#include "kseq.h" // FASTA/Q parser
+KSEQ_INIT(gzFile, gzread)
+
+void yak_copt_init(yak_copt_t *o)
+{
+	memset(o, 0, sizeof(yak_copt_t));
+	o->bf_shift = 0;
+	o->bf_n_hash = 4;
+	o->k = 31;
+	o->pre = YAK_COUNTER_BITS;
+	o->n_thread = 4;
+	o->chunk_size = 10000000;
+}
+
+typedef struct {
+	int n, m;
+	uint64_t n_ins;
+	uint64_t *a;
+} ch_buf_t;
+
+static inline void ch_insert_buf(ch_buf_t *buf, int p, uint64_t y) // insert a k-mer $y to a linear buffer
+{
+	int pre = y & ((1<<p) - 1);
+	ch_buf_t *b = &buf[pre];
+	if (b->n == b->m) {
+		b->m = b->m < 8? 8 : b->m + (b->m>>1);
+		REALLOC(b->a, b->m);
+	}
+	b->a[b->n++] = y;
+}
+
+static void count_seq_buf(ch_buf_t *buf, int k, int p, int len, const char *seq) // insert k-mers in $seq to linear buffer $buf
+{
+	int i, l;
+	uint64_t x[4], mask = (1ULL<<k) - 1, shift = k - 1;
+	for (i = l = 0, x[0] = x[1] = x[2] = x[3] = 0; i < len; ++i) {
+		int c = seq_nt4_table[(uint8_t)seq[i]];
+		if (c < 4) { // not an "N" base
+			x[0] = (x[0] << 1 | (c&1))  & mask;
+			x[1] = (x[1] << 1 | (c>>1)) & mask;
+			x[2] = x[2] >> 1 | (uint64_t)(1 - (c&1))  << shift;
+			x[3] = x[3] >> 1 | (uint64_t)(1 - (c>>1)) << shift;
+			if (++l >= k)
+				ch_insert_buf(buf, p, yak_hash_long(x));
+		} else l = 0, x[0] = x[1] = x[2] = x[3] = 0; // if there is an "N", restart
+	}
+}
+
+typedef struct { // global data structure for kt_pipeline()
+	const yak_copt_t *opt;
+	int create_new;
+	kseq_t *ks;
+	yak_ch_t *h;
+} pldat_t;
+
+typedef struct { // data structure for each step in kt_pipeline()
+	pldat_t *p;
+	int n, m, sum_len, nk;
+	int *len;
+	char **seq;
+	ch_buf_t *buf;
+} stepdat_t;
+
+static void worker_for(void *data, long i, int tid) // callback for kt_for()
+{
+	stepdat_t *s = (stepdat_t*)data;
+	ch_buf_t *b = &s->buf[i];
+	yak_ch_t *h = s->p->h;
+	b->n_ins += yak_ch_insert_list(h, s->p->create_new, b->n, b->a);
+}
+
+static void *worker_count_all(void *data, int step, void *in) // callback for kt_pipeline()
+{
+	pldat_t *p = (pldat_t*)data;
+	if (step == 0) { // step 1: read a block of sequences
+		int ret;
+		stepdat_t *s;
+		CALLOC(s, 1);
+		s->p = p;
+		while ((ret = kseq_read(p->ks)) >= 0) {
+			int l = p->ks->seq.l;
+			if (l < p->opt->k) continue;
+			if (s->n == s->m) {
+				s->m = s->m < 16? 16 : s->m + (s->n>>1);
+				REALLOC(s->len, s->m);
+				REALLOC(s->seq, s->m);
+			}
+			MALLOC(s->seq[s->n], l);
+			memcpy(s->seq[s->n], p->ks->seq.s, l);
+			s->len[s->n++] = l;
+			s->sum_len += l;
+			s->nk += l - p->opt->k + 1;
+			if (s->sum_len >= p->opt->chunk_size)
+				break;
+		}
+		if (s->sum_len == 0) free(s);
+		else return s;
+	} else if (step == 1) { // step 2: extract k-mers
+		stepdat_t *s = (stepdat_t*)in;
+		int i, n = 1<<p->opt->pre, m;
+		CALLOC(s->buf, n);
+		m = (int)(s->nk * 1.2 / n) + 1;
+		for (i = 0; i < n; ++i) {
+			s->buf[i].m = m;
+			MALLOC(s->buf[i].a, m);
+		}
+		for (i = 0; i < s->n; ++i) {
+			count_seq_buf(s->buf, p->opt->k, p->opt->pre, s->len[i], s->seq[i]);
+			free(s->seq[i]);
+		}
+		free(s->seq); free(s->len);
+		return s;
+	} else if (step == 2) { // step 3: insert k-mers to hash table
+		stepdat_t *s = (stepdat_t*)in;
+		int i, n = 1<<p->opt->pre;
+		uint64_t n_ins = 0;
+		kt_for(p->opt->n_thread, worker_for, s, n);
+		for (i = 0; i < n; ++i) {
+			n_ins += s->buf[i].n_ins;
+			free(s->buf[i].a);
+		}
+		p->h->tot += n_ins;
+		free(s->buf);
+		fprintf(stderr, "[M::%s::%.3f*%.2f] processed %d sequences; %ld distinct k-mers in the hash table\n", __func__,
+				yak_realtime(), yak_cputime() / yak_realtime(), s->n, (long)p->h->tot);
+		free(s);
+	}
+	return 0;
+}
+
+yak_ch_t *yak_count(const char *fn, const yak_copt_t *opt, yak_ch_t *h0)
+{
+	pldat_t pl;
+	gzFile fp;
+	if ((fp = gzopen(fn, "r")) == 0) return 0;
+	pl.ks = kseq_init(fp);
+	pl.opt = opt;
+	if (h0) {
+		pl.h = h0, pl.create_new = 0;
+		assert(h0->k == opt->k && h0->pre == opt->pre);
+	} else {
+		pl.create_new = 1;
+		pl.h = yak_ch_init(opt->k, opt->pre, opt->bf_n_hash, opt->bf_shift);
+	}
+	kt_pipeline(3, worker_count_all, &pl, 3);
+	kseq_destroy(pl.ks);
+	gzclose(fp);
+	return pl.h;
+}
+
+yak_ch_t *yak_count_file(const yak_copt_t *opt, int n_fn, char **fn)
+{
+	int i;
+	yak_ch_t *h = 0;
+	for (i = 0; i < n_fn; ++i)
+		h = yak_count(fn[i], opt, h);
+	if (opt->bf_shift > 0)
+		yak_ch_destroy_bf(h);
+	return h;
+}
+
+void ha_count_high(const hifiasm_opt_t *asm_opt)
+{
+	int64_t cnt[YAK_N_COUNTS];
+	yak_copt_t opt;
+	yak_ch_t *h;
+	yak_copt_init(&opt);
+	opt.k = asm_opt->k_mer_length;
+	opt.n_thread = asm_opt->thread_num;
+	opt.bf_shift = asm_opt->bf_shift;
+	h = yak_count_file(&opt, asm_opt->num_reads, asm_opt->read_file_names);
+	yak_ch_hist(h, cnt, opt.n_thread);
+	yak_ch_destroy(h);
+}
diff --git a/yak-sys.cpp b/yak-sys.cpp
new file mode 100644
index 0000000..d01c68c
--- /dev/null
+++ b/yak-sys.cpp
@@ -0,0 +1,43 @@
+#include <sys/resource.h>
+#include <sys/time.h>
+#include "yak.h"
+
+int yak_verbose = 3;
+
+static double yak_realtime0;
+
+double yak_cputime(void)
+{
+	struct rusage r;
+	getrusage(RUSAGE_SELF, &r);
+	return r.ru_utime.tv_sec + r.ru_stime.tv_sec + 1e-6 * (r.ru_utime.tv_usec + r.ru_stime.tv_usec);
+}
+
+static inline double yak_realtime_core(void)
+{
+	struct timeval tp;
+	struct timezone tzp;
+	gettimeofday(&tp, &tzp);
+	return tp.tv_sec + tp.tv_usec * 1e-6;
+}
+
+void yak_reset_realtime(void)
+{
+	yak_realtime0 = yak_realtime_core();
+}
+
+double yak_realtime(void)
+{
+	return yak_realtime_core() - yak_realtime0;
+}
+
+long yak_peakrss(void)
+{
+	struct rusage r;
+	getrusage(RUSAGE_SELF, &r);
+#ifdef __linux__
+	return r.ru_maxrss * 1024;
+#else
+	return r.ru_maxrss;
+#endif
+}
diff --git a/yak.h b/yak.h
new file mode 100644
index 0000000..31529b7
--- /dev/null
+++ b/yak.h
@@ -0,0 +1,68 @@
+#ifndef __YAK_H__
+#define __YAK_H__
+#include <stdint.h>
+
+#define YAK_BLK_SHIFT  9 // 64 bytes, the size of a cache line
+#define YAK_BLK_MASK   ((1<<(YAK_BLK_SHIFT)) - 1)
+
+typedef struct {
+	int n_shift, n_hashes;
+	uint8_t *b;
+} yak_bf_t;
+
+extern const unsigned char seq_nt4_table[256];
+
+void trio_partition(void);
+
+double yak_cputime(void);
+void yak_reset_realtime(void);
+double yak_realtime(void);
+long yak_peakrss(void);
+
+yak_bf_t *yak_bf_init(int n_shift, int n_hashes);
+void yak_bf_destroy(yak_bf_t *b);
+int yak_bf_insert(yak_bf_t *b, uint64_t hash);
+
+static inline uint64_t yak_hash64(uint64_t key, uint64_t mask) // invertible integer hash function
+{
+	key = (~key + (key << 21)) & mask; // key = (key << 21) - key - 1;
+	key = key ^ key >> 24;
+	key = ((key + (key << 3)) + (key << 8)) & mask; // key * 265
+	key = key ^ key >> 14;
+	key = ((key + (key << 2)) + (key << 4)) & mask; // key * 21
+	key = key ^ key >> 28;
+	key = (key + (key << 31)) & mask;
+	return key;
+}
+
+static inline uint64_t yak_hash64_64(uint64_t key)
+{
+	key = ~key + (key << 21);
+	key = key ^ key >> 24;
+	key = (key + (key << 3)) + (key << 8);
+	key = key ^ key >> 14;
+	key = (key + (key << 2)) + (key << 4);
+	key = key ^ key >> 28;
+	key = key + (key << 31);
+	return key;
+}
+
+static inline uint64_t yak_hash_long(uint64_t x[4])
+{
+	int j = x[1] < x[3]? 0 : 1;
+	return yak_hash64_64(x[j<<1|0]) + yak_hash64_64(x[j<<1|1]);
+}
+
+#define CALLOC(ptr, len) ((ptr) = (__typeof__(ptr))calloc((len), sizeof(*(ptr))))
+#define MALLOC(ptr, len) ((ptr) = (__typeof__(ptr))malloc((len) * sizeof(*(ptr))))
+#define REALLOC(ptr, len) ((ptr) = (__typeof__(ptr))realloc((ptr), (len) * sizeof(*(ptr))))
+
+#ifndef klib_unused
+#if (defined __clang__ && __clang_major__ >= 3) || (defined __GNUC__ && __GNUC__ >= 3)
+#define klib_unused __attribute__ ((__unused__))
+#else
+#define klib_unused
+#endif
+#endif /* klib_unused */
+
+#endif // __YAK_H__