diff --git a/base1432.c b/base1432.c
index 9089ab0..faef239 100644
--- a/base1432.c
+++ b/base1432.c
@@ -30,7 +30,7 @@ typedef union {
 int base16384_encode_safe(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -127,7 +127,7 @@ int base16384_encode_safe(const char* data, int dlen, char* buf) {
 int base16384_encode(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -202,7 +202,7 @@ int base16384_encode(const char* data, int dlen, char* buf) {
 int base16384_encode_unsafe(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -244,7 +244,7 @@ int base16384_decode_safe(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
@@ -259,7 +259,7 @@ int base16384_decode_safe(const char* data, int dlen, char* buf) {
 	const uint32_t* vals = (const uint32_t*)data;
 	uint32_t n = 0;
 	int32_t i = 0;
-	for(; i < outlen - 7; i+=7) {	// n实际每次自增2
+	for(; i < outlen - 7; i+=7) {	// n += 2 in one loop
 		register uint32_t sum = 0;
 		register uint32_t shift = htobe32(vals[n++]) - 0x4e004e00;
 		shift <<= 2;
@@ -341,7 +341,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
@@ -356,7 +356,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 	const uint32_t* vals = (const uint32_t*)data;
 	uint32_t n = 0;
 	int32_t i = 0;
-	for(; i <= outlen - 7; i+=7) {	// n实际每次自增2
+	for(; i <= outlen - 7; i+=7) {	// n += 2 in one loop
 		register uint32_t sum = 0;
 		register uint32_t shift = htobe32(vals[n++]) - 0x4e004e00;
 		shift <<= 2;
@@ -375,7 +375,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 	}
 	if(*(uint8_t*)(&vals[n]) == '=') return outlen;
 	if(offset--) {
-		// 这里有读取越界
+		// here comes a read overlap
 		#ifdef WORDS_BIGENDIAN
 			register uint32_t sum = __builtin_bswap32(vals[n++]);
 		#else
@@ -391,7 +391,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 				if(offset--) {
 					buf[i] = (sum & 0x0f000000) >> 20;
 					if(*(uint8_t*)(&vals[n]) == '=') return outlen;
-					// 这里有读取越界
+					// here comes a read overlap
 					#ifdef WORDS_BIGENDIAN
 						sum = __builtin_bswap32(vals[n]);
 					#else
@@ -418,7 +418,7 @@ int base16384_decode_unsafe(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
@@ -433,7 +433,7 @@ int base16384_decode_unsafe(const char* data, int dlen, char* buf) {
 	const uint32_t* vals = (const uint32_t*)data;
 	uint32_t n = 0;
 	int32_t i = 0;
-	for(; i < outlen-7; i+=7) {	// n实际每次自增2
+	for(; i < outlen-7; i+=7) {	// n += 2 in one loop
 		register uint32_t sum = 0;
 		register uint32_t shift = htobe32(vals[n++]) - 0x4e004e00;
 		shift <<= 2;
diff --git a/base1464.c b/base1464.c
index 1cfc786..80bc49c 100644
--- a/base1464.c
+++ b/base1464.c
@@ -30,7 +30,7 @@ typedef union {
 int base16384_encode_safe(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -112,7 +112,7 @@ int base16384_encode_safe(const char* data, int dlen, char* buf) {
 int base16384_encode(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -127,7 +127,7 @@ int base16384_encode(const char* data, int dlen, char* buf) {
 	int64_t i = 0;
 	for(; i <= dlen - 7; i += 7) {
 		register uint64_t sum = 0;
-		register uint64_t shift = htobe64(*(uint64_t*)(data+i))>>2; // 这里有读取越界
+		register uint64_t shift = htobe64(*(uint64_t*)(data+i))>>2; // here comes a read overlap
 		sum |= shift & 0x3fff000000000000;
 		shift >>= 2;
 		sum |= shift & 0x00003fff00000000;
@@ -177,7 +177,7 @@ int base16384_encode(const char* data, int dlen, char* buf) {
 int base16384_encode_unsafe(const char* data, int dlen, char* buf) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的2字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -192,7 +192,7 @@ int base16384_encode_unsafe(const char* data, int dlen, char* buf) {
 	int64_t i = 0;
 	for(; i < dlen; i += 7) {
 		register uint64_t sum = 0;
-		register uint64_t shift = htobe64(*(uint64_t*)(data+i))>>2; // 这里有读取越界
+		register uint64_t shift = htobe64(*(uint64_t*)(data+i))>>2; // here comes a read overlap
 		sum |= shift & 0x3fff000000000000;
 		shift >>= 2;
 		sum |= shift & 0x00003fff00000000;
@@ -215,7 +215,7 @@ int base16384_decode_safe(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
@@ -292,7 +292,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
@@ -322,7 +322,7 @@ int base16384_decode(const char* data, int dlen, char* buf) {
 	}
 	if(*(uint8_t*)(&vals[n]) == '=') return outlen;
 	if(offset--) {
-		// 这里有读取越界
+		// here comes a read overlap
 		#ifdef WORDS_BIGENDIAN
 			register uint64_t sum = __builtin_bswap64(vals[n]) - 0x000000000000004e;
 		#else
@@ -356,7 +356,7 @@ int base16384_decode_unsafe(const char* data, int dlen, char* buf) {
 	int offset = 0;
 	if(data[dlen-2] == '=') {
 		offset = data[dlen-1];
-		switch(offset) {	// 算上偏移标志字符占用的2字节
+		switch(offset) {	// also count 0x3dxx
 			case 0: break;
 			case 1: outlen -= 4; break;
 			case 2:
diff --git a/base16384.h b/base16384.h
index e0631a8..c24a05b 100644
--- a/base16384.h
+++ b/base16384.h
@@ -66,7 +66,7 @@ typedef enum base16384_err_t base16384_err_t;
  * @param count read bytes count
  * @return the size read
 */
-typedef ssize_t(*base16384_reader_t)(const void *client_data, void *buffer, size_t count);
+typedef ssize_t (*base16384_reader_t)(const void *client_data, void *buffer, size_t count);
 
 /**
  * @brief custom writer function interface
@@ -75,13 +75,16 @@ typedef ssize_t(*base16384_reader_t)(const void *client_data, void *buffer, size
  * @param count write bytes count
  * @return the size written
 */
-typedef ssize_t(*base16384_writer_t)(const void *client_data, const void *buffer, size_t count);
+typedef ssize_t (*base16384_writer_t)(const void *client_data, const void *buffer, size_t count);
+
+union base16384_io_function_t {
+	base16384_reader_t reader;
+	base16384_writer_t writer;
+};
+typedef union base16384_io_function_t base16384_io_function_t;
 
 struct base16384_stream_t {
-	const union {
-		base16384_reader_t reader;
-		base16384_writer_t writer;
-	} f;
+	const base16384_io_function_t f;
 	const void *client_data;
 };
 /**
@@ -97,7 +100,7 @@ typedef struct base16384_stream_t base16384_stream_t;
 static inline int _base16384_encode_len(int dlen) {
 	int outlen = dlen / 7 * 8;
 	int offset = dlen % 7;
-	switch(offset) {	// 算上偏移标志字符占用的 2 字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen += 4; break;
 		case 2:
@@ -127,7 +130,7 @@ static inline int base16384_encode_len(int dlen) {
 */
 static inline int _base16384_decode_len(int dlen, int offset) {
 	int outlen = dlen;
-	switch(offset) {	// 算上偏移标志字符占用的 2 字节
+	switch(offset) {	// also count 0x3dxx
 		case 0: break;
 		case 1: outlen -= 4; break;
 		case 2: