diff --git a/src/protocol/MySQLMessage.cc b/src/protocol/MySQLMessage.cc
index 04225afe..c13c9723 100644
--- a/src/protocol/MySQLMessage.cc
+++ b/src/protocol/MySQLMessage.cc
@@ -102,7 +102,7 @@ int MySQLMessage::append(const void *buf, size_t *size)
 	{
 		seqid_ = mysql_stream_get_seq(stream_);
 		mysql_stream_get_buf(&stream_buf, &stream_len, stream_);
-		ret = decode_packet((const char *)stream_buf, stream_len);
+		ret = decode_packet((const unsigned char *)stream_buf, stream_len);
 		if (ret == -2)
 		{
 			errno = EBADMSG;
@@ -115,10 +115,10 @@ int MySQLMessage::append(const void *buf, size_t *size)
 
 int MySQLMessage::encode(struct iovec vectors[], int max)
 {
-	const char *p = buf_.c_str();
+	const unsigned char *p = (unsigned char *)buf_.c_str();
 	size_t nleft = buf_.size();
 	uint8_t seqid_start = seqid_;
-	char *head;
+	unsigned char *head;
 	uint32_t length;
 	int i = 0;
 
@@ -132,7 +132,7 @@ int MySQLMessage::encode(struct iovec vectors[], int max)
 		vectors[i].iov_base = head;
 		vectors[i].iov_len = 4;
 		i++;
-		vectors[i].iov_base = const_cast<char *>(p);
+		vectors[i].iov_base = const_cast<unsigned char *>(p);
 		vectors[i].iov_len = length;
 		i++;
 
@@ -188,10 +188,10 @@ int MySQLHandshakeResponse::encode(struct iovec vectors[], int max)
 	return this->MySQLMessage::encode(vectors, max);
 }
 
-int MySQLHandshakeResponse::decode_packet(const char *buf, size_t buflen)
+int MySQLHandshakeResponse::decode_packet(const unsigned char *buf, size_t buflen)
 {
-	const char *end = buf + buflen;
-	const char *pos;
+	const unsigned char *end = buf + buflen;
+	const unsigned char *pos;
 
 	if (buflen == 0)
 		return -2;
@@ -201,7 +201,7 @@ int MySQLHandshakeResponse::decode_packet(const char *buf, size_t buflen)
 	{
 		if (buflen >= 4)
 		{
-			const_cast<char *>(buf)[3] = '#';
+			const_cast<unsigned char *>(buf)[3] = '#';
 			if (mysql_parser_parse(buf, buflen, parser_) == 1)
 			{
 				disallowed_ = true;
@@ -220,7 +220,7 @@ int MySQLHandshakeResponse::decode_packet(const char *buf, size_t buflen)
 	if (pos >= end || end - pos < 43)
 		return -2;
 
-	server_version_.assign(buf, pos - buf);
+	server_version_.assign((const char *)buf, pos - buf);
 	buf = pos + 1;
 	connection_id_ = uint4korr(buf);
 	buf += 4;
@@ -262,8 +262,8 @@ static inline std::string __sha1_bin(const std::string& str)
 int MySQLAuthRequest::encode(struct iovec vectors[], int max)
 {
 	std::string native;
-	char header[32] = {0};
-	char *pos = header;
+	unsigned char header[32] = {0};
+	unsigned char *pos = header;
 
 	int4store(pos, MYSQL_CAPFLAG_CLIENT_PROTOCOL_41 |
 				   MYSQL_CAPFLAG_CLIENT_SECURE_CONNECTION |
@@ -290,17 +290,17 @@ int MySQLAuthRequest::encode(struct iovec vectors[], int max)
 	}
 
 	buf_.clear();
-	buf_.append(header, 32);
+	buf_.append((char *)header, 32);
 	buf_.append(username_.c_str(), username_.size() + 1);
 	buf_.append(native);
 	buf_.append(db_.c_str(), db_.size() + 1);
 	return this->MySQLMessage::encode(vectors, max);
 }
 
-int MySQLAuthRequest::decode_packet(const char *buf, size_t buflen)
+int MySQLAuthRequest::decode_packet(const unsigned char *buf, size_t buflen)
 {
-	const char *end = buf + buflen;
-	const char *pos;
+	const unsigned char *end = buf + buflen;
+	const unsigned char *pos;
 
 	if (buflen < 32)
 		return -2;
@@ -321,7 +321,7 @@ int MySQLAuthRequest::decode_packet(const char *buf, size_t buflen)
 	if (pos >= end)
 		return -2;
 
-	username_.assign(buf, pos - buf);
+	username_.assign((const char *)buf, pos - buf);
 	buf = pos + 1;
 
 	return 1;
@@ -337,7 +337,7 @@ void MySQLResponse::set_ok_packet()
 	buf_.append((const char *)&zero16, 2);
 }
 
-int MySQLResponse::decode_packet(const char *buf, size_t buflen)
+int MySQLResponse::decode_packet(const unsigned char *buf, size_t buflen)
 {
 	return mysql_parser_parse(buf, buflen, parser_);
 }
diff --git a/src/protocol/MySQLMessage.h b/src/protocol/MySQLMessage.h
index a42b431f..728901ba 100644
--- a/src/protocol/MySQLMessage.h
+++ b/src/protocol/MySQLMessage.h
@@ -45,7 +45,7 @@ public:
 protected:
 	virtual int append(const void *buf, size_t *size);
 	virtual int encode(struct iovec vectors[], int max);
-	virtual int decode_packet(const char *buf, size_t buflen) { return 1; }
+	virtual int decode_packet(const unsigned char *buf, size_t buflen) { return 1; }
 
 	void set_command(int cmd) const;
 
@@ -54,7 +54,7 @@ protected:
 	mysql_parser_t *parser_;
 
 	//encode
-	char heads_[256][4];
+	unsigned char heads_[256][4];
 	uint8_t seqid_;
 	std::string buf_;
 	size_t cur_size_;
@@ -112,7 +112,7 @@ public:
 	MySQLResponse& operator= (MySQLResponse&& move) = default;
 
 protected:
-	virtual int decode_packet(const char *buf, size_t buflen);
+	virtual int decode_packet(const unsigned char *buf, size_t buflen);
 };
 
 }
diff --git a/src/protocol/MySQLMessage.inl b/src/protocol/MySQLMessage.inl
index c4e677dd..bcfe3eab 100644
--- a/src/protocol/MySQLMessage.inl
+++ b/src/protocol/MySQLMessage.inl
@@ -58,7 +58,7 @@ public:
 	bool host_disallowed() const { return this->disallowed_; }
 
 private:
-	virtual int decode_packet(const char *buf, size_t buflen);
+	virtual int decode_packet(const unsigned char *buf, size_t buflen);
 
 	uint8_t protocol_version_;
 	std::string server_version_;
@@ -98,7 +98,7 @@ public:
 
 private:
 	virtual int encode(struct iovec vectors[], int max);
-	virtual int decode_packet(const char *buf, size_t buflen);
+	virtual int decode_packet(const unsigned char *buf, size_t buflen);
 
 	std::string username_;
 	std::string password_;
diff --git a/src/protocol/MySQLResult.cc b/src/protocol/MySQLResult.cc
index e3dcd677..01a95727 100644
--- a/src/protocol/MySQLResult.cc
+++ b/src/protocol/MySQLResult.cc
@@ -162,18 +162,18 @@ bool MySQLResultCursor::fetch_row(std::vector<MySQLCell>& row_arr)
 		return false;
 
 	unsigned long long len;
-	const char *data;
+	const unsigned char *data;
 	int data_type;
 
-	const char *p = (const char *)this->pos;
-	const char *end = (const char *)this->end;
+	const unsigned char *p = (const unsigned char *)this->pos;
+	const unsigned char *end = (const unsigned char *)this->end;
 	
 	row_arr.clear();
 
 	for (int i = 0; i < this->field_count; i++)
 	{
 		data_type = this->fields[i]->get_data_type();
-		if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_NULL)
+		if (*p == MYSQL_PACKET_HEADER_NULL)
 		{
 			data = NULL;
 			len = 0;
@@ -211,14 +211,14 @@ bool MySQLResultCursor::fetch_row_nocopy(const void **data, size_t *len, int *da
 		return false;
 
 	unsigned long long cell_len;
-	const char *cell_data;
+	const unsigned char *cell_data;
 
-	const char *p = (const char *)this->pos;
-	const char *end = (const char *)this->end;
+	const unsigned char *p = (const unsigned char *)this->pos;
+	const unsigned char *end = (const unsigned char *)this->end;
 
 	for (int i = 0; i < this->field_count; i++)
 	{	
-		if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_NULL)
+		if (*p == MYSQL_PACKET_HEADER_NULL)
 		{
 			cell_data = NULL;
 			cell_len = 0;
@@ -246,11 +246,11 @@ bool MySQLResultCursor::fetch_all(std::vector<std::vector<MySQLCell>>& rows)
 		return false;
 
 	unsigned long long len;
-	const char *data;
+	const unsigned char *data;
 	int data_type;
 
-	const char *p = (const char *)this->pos;
-	const char *end = (const char *)this->end;
+	const unsigned char *p = (const unsigned char *)this->pos;
+	const unsigned char *end = (const unsigned char *)this->end;
 
 	rows.clear();
 
@@ -260,7 +260,7 @@ bool MySQLResultCursor::fetch_all(std::vector<std::vector<MySQLCell>>& rows)
 		for (int j = 0; j < this->field_count; j++)
 		{
 			data_type = this->fields[j]->get_data_type();
-			if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_NULL)
+			if (*p == MYSQL_PACKET_HEADER_NULL)
 			{
 				data = NULL;
 				len = 0;
diff --git a/src/protocol/MySQLResult.inl b/src/protocol/MySQLResult.inl
index f48c4a3a..95805cf5 100644
--- a/src/protocol/MySQLResult.inl
+++ b/src/protocol/MySQLResult.inl
@@ -294,18 +294,18 @@ bool MySQLResultCursor::fetch_row(T& row_map)
 		return false;
 
 	unsigned long long len;
-	const char *data;
+	const unsigned char *data;
 	int data_type;
 
-	const char *p = (const char *)this->pos;
-	const char *end = (const char *)this->end;
+	const unsigned char *p = (const unsigned char *)this->pos;
+	const unsigned char *end = (const unsigned char *)this->end;
 
 	row_map.clear();
 
 	for (int i = 0; i < this->field_count; i++)
 	{
 		data_type = this->fields[i]->get_data_type();
-		if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_NULL)
+		if (*p == MYSQL_PACKET_HEADER_NULL)
 		{
 			data = NULL;
 			len = 0;
diff --git a/src/protocol/mysql_byteorder.c b/src/protocol/mysql_byteorder.c
index 387b68bd..47de046d 100644
--- a/src/protocol/mysql_byteorder.c
+++ b/src/protocol/mysql_byteorder.c
@@ -18,15 +18,15 @@
 
 #include "mysql_byteorder.h"
 
-int decode_length_safe(unsigned long long *res, const char **pos, const char *end)
+int decode_length_safe(unsigned long long *res, const unsigned char **pos,
+					   const unsigned char *end)
 {
-	//const unsigned char *p = (const unsigned char *)*pos;
-	const char *p = *pos;
+	const unsigned char *p = *pos;
 
-	switch (*(const unsigned char *)p)
+	switch (*p)
 	{
 	default:
-		*res = *(const unsigned char *)p;
+		*res = *p;
 		*pos = p + 1;
 		break;
 
@@ -63,8 +63,8 @@ int decode_length_safe(unsigned long long *res, const char **pos, const char *en
 	return 1;
 }
 
-int decode_string(const char **str, unsigned long long *len,
-				  const char **pos, const char *end)
+int decode_string(const unsigned char **str, unsigned long long *len,
+				  const unsigned char **pos, const unsigned char *end)
 {
 	unsigned long long length;
 
diff --git a/src/protocol/mysql_byteorder.h b/src/protocol/mysql_byteorder.h
index ccc12885..42d06163 100644
--- a/src/protocol/mysql_byteorder.h
+++ b/src/protocol/mysql_byteorder.h
@@ -25,248 +25,377 @@
 
 #if __BYTE_ORDER == __LITTLE_ENDIAN
 
-static inline int16_t sint2korr(const char *A) {
-  int16_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline int16_t sint2korr(const unsigned char *A)
+{
+	int16_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline int32_t sint4korr(const char *A) {
-  int32_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline int32_t sint4korr(const unsigned char *A)
+{
+	int32_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline uint16_t uint2korr(const char *A) {
-  uint16_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline uint16_t uint2korr(const unsigned char *A)
+{
+	uint16_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline uint32_t uint4korr(const char *A) {
-  uint32_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline uint32_t uint4korr(const unsigned char *A)
+{
+	uint32_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline uint64_t uint8korr(const char *A) {
-  uint64_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline uint64_t uint8korr(const unsigned char *A)
+{
+	uint64_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline int64_t sint8korr(const char *A) {
-  int64_t ret;
-  memcpy(&ret, A, sizeof(ret));
-  return ret;
+static inline int64_t sint8korr(const unsigned char *A)
+{
+	int64_t ret;
+	memcpy(&ret, A, sizeof(ret));
+	return ret;
 }
 
-static inline void int2store(char *T, uint16_t A) { memcpy(T, &A, sizeof(A)); }
-
-static inline void int4store(char *T, uint32_t A) { memcpy(T, &A, sizeof(A)); }
-
-static inline void int7store(char *T, uint64_t A) { memcpy(T, &A, 7); }
-
-static inline void int8store(char *T, uint64_t A) {
-  memcpy(T, &A, sizeof(A));
+static inline void int2store(unsigned char *T, uint16_t A)
+{
+	memcpy(T, &A, sizeof(A));
 }
 
-static inline void float4get(float *V, const char *M) {
-  memcpy(V, (M), sizeof(float));
+static inline void int4store(unsigned char *T, uint32_t A)
+{
+	memcpy(T, &A, sizeof(A));
 }
 
-static inline void float4store(char *V, float M) {
-  memcpy(V, (&M), sizeof(float));
+static inline void int7store(unsigned char *T, uint64_t A)
+{
+	memcpy(T, &A, 7);
 }
 
-static inline void float8get(double *V, const char *M) {
-  memcpy(V, M, sizeof(double));
+static inline void int8store(unsigned char *T, uint64_t A)
+{
+	memcpy(T, &A, sizeof(A));
 }
 
-static inline void float8store(char *V, double M) {
-  memcpy(V, &M, sizeof(double));
+static inline void float4get(float *V, const unsigned char *M)
+{
+	memcpy(V, (M), sizeof(float));
 }
 
-static inline void floatget(float *V, const char *M) { float4get(V, M); }
-static inline void floatstore(char *V, float M) { float4store(V, M); }
-
-static inline void doublestore(char *T, double V) {
-  memcpy(T, &V, sizeof(double));
-}
-static inline void doubleget(double *V, const char *M) {
-  memcpy(V, M, sizeof(double));
+static inline void float4store(unsigned char *V, float M)
+{
+	memcpy(V, (&M), sizeof(float));
 }
 
-static inline void ushortget(uint16_t *V, const char *pM) { *V = uint2korr(pM); }
-static inline void shortget(int16_t *V, const char *pM) { *V = sint2korr(pM); }
-static inline void longget(int32_t *V, const char *pM) { *V = sint4korr(pM); }
-static inline void ulongget(uint32_t *V, const char *pM) { *V = uint4korr(pM); }
-static inline void shortstore(char *T, int16_t V) { int2store(T, V); }
-static inline void longstore(char *T, int32_t V) { int4store(T, V); }
-
-static inline void longlongget(int64_t *V, const char *M) {
-  memcpy(V, (M), sizeof(uint64_t));
+static inline void float8get(double *V, const unsigned char *M)
+{
+	memcpy(V, M, sizeof(double));
 }
-static inline void longlongstore(char *T, int64_t V) {
-  memcpy((T), &V, sizeof(uint64_t));
+
+static inline void float8store(unsigned char *V, double M)
+{
+	memcpy(V, &M, sizeof(double));
+}
+
+static inline void floatget(float *V, const unsigned char *M)
+{
+	float4get(V, M);
+}
+
+static inline void floatstore(unsigned char *V, float M)
+{
+	float4store(V, M);
+}
+
+static inline void doublestore(unsigned char *T, double V)
+{
+	memcpy(T, &V, sizeof(double));
+}
+static inline void doubleget(double *V, const unsigned char *M)
+{
+	memcpy(V, M, sizeof(double));
+}
+
+static inline void ushortget(uint16_t *V, const unsigned char *pM)
+{
+	*V = uint2korr(pM);
+}
+
+static inline void shortget(int16_t *V, const unsigned char *pM)
+{
+	*V = sint2korr(pM);
+}
+
+static inline void longget(int32_t *V, const unsigned char *pM)
+{
+	*V = sint4korr(pM);
+}
+
+static inline void ulongget(uint32_t *V, const unsigned char *pM)
+{
+	*V = uint4korr(pM);
+}
+
+static inline void shortstore(unsigned char *T, int16_t V)
+{
+	int2store(T, V);
+}
+
+static inline void longstore(unsigned char *T, int32_t V)
+{
+	int4store(T, V);
+}
+
+static inline void longlongget(int64_t *V, const unsigned char *M)
+{
+	memcpy(V, (M), sizeof(uint64_t));
+}
+
+static inline void longlongstore(unsigned char *T, int64_t V)
+{
+	memcpy((T), &V, sizeof(uint64_t));
+}
+
+static inline int32_t sint3korr(const unsigned char *A)
+{
+	int32_t ret = 0;
+	memcpy(&ret, A, 3);
+	return ret;
+}
+
+static inline uint32_t uint3korr(const unsigned char *A)
+{
+	uint32_t ret = 0;
+	memcpy(&ret, A, 3);
+	return ret;
+}
+
+static inline void int3store(unsigned char *T, uint32_t A)
+{
+	memcpy(T, &A, 3);
 }
 
 #elif __BYTE_ORDER == __BIG_ENDIAN
 
-static inline int16_t sint2korr(const char *A) {
-  return (int16_t)(((int16_t)(A[0])) + ((int16_t)(A[1]) << 8));
+static inline int16_t sint2korr(const unsigned char *A)
+{
+	return (int16_t)(((int16_t)(A[0])) + ((int16_t)(A[1]) << 8));
 }
 
-static inline int32_t sint4korr(const char *A) {
-  return (int32_t)(((int32_t)(A[0])) + (((int32_t)(A[1]) << 8)) +
-                 (((int32_t)(A[2]) << 16)) + (((int32_t)(A[3]) << 24)));
+static inline int32_t sint4korr(const unsigned char *A)
+{
+	return (int32_t)(((int32_t)(A[0])) + (((int32_t)(A[1]) << 8)) +
+		   (((int32_t)(A[2]) << 16)) + (((int32_t)(A[3]) << 24)));
 }
 
-static inline uint16_t uint2korr(const char *A) {
-  return (uint16_t)(((uint16_t)(A[0])) + ((uint16_t)(A[1]) << 8));
+static inline uint16_t uint2korr(const unsigned char *A)
+{
+	return (uint16_t)(((uint16_t)(A[0])) + ((uint16_t)(A[1]) << 8));
 }
 
-static inline uint32_t uint4korr(const char *A) {
-  return (uint32_t)(((uint32_t)(A[0])) + (((uint32_t)(A[1])) << 8) +
-                  (((uint32_t)(A[2])) << 16) + (((uint32_t)(A[3])) << 24));
+static inline uint32_t uint4korr(const unsigned char *A)
+{
+	return (uint32_t)(((uint32_t)(A[0])) + (((uint32_t)(A[1])) << 8) +
+		   (((uint32_t)(A[2])) << 16) + (((uint32_t)(A[3])) << 24));
 }
 
-static inline uint64_t uint8korr(const char *A) {
-  return ((uint64_t)(((uint32_t)(A[0])) + (((uint32_t)(A[1])) << 8) +
-                      (((uint32_t)(A[2])) << 16) + (((uint32_t)(A[3])) << 24)) +
-          (((uint64_t)(((uint32_t)(A[4])) + (((uint32_t)(A[5])) << 8) +
-                        (((uint32_t)(A[6])) << 16) + (((uint32_t)(A[7])) << 24)))
-           << 32));
+static inline uint64_t uint8korr(const unsigned char *A)
+{
+	return ((uint64_t)(((uint32_t)(A[0])) + (((uint32_t)(A[1])) << 8) +
+		   (((uint32_t)(A[2])) << 16) + (((uint32_t)(A[3])) << 24)) +
+		   (((uint64_t)(((uint32_t)(A[4])) + (((uint32_t)(A[5])) << 8) +
+		   (((uint32_t)(A[6])) << 16) + (((uint32_t)(A[7])) << 24))) << 32));
 }
 
-static inline int64_t sint8korr(const char *A) {
-  return (int64_t)uint8korr(A);
+static inline int64_t sint8korr(const unsigned char *A)
+{
+	return (int64_t)uint8korr(A);
 }
 
-static inline void int2store(char *T, uint16_t A) {
-  uint def_temp = A;
-  *(T) = (char)(def_temp);
-  *(T + 1) = (char)(def_temp >> 8);
+static inline void int2store(unsigned char *T, uint16_t A)
+{
+	uint def_temp = A;
+	*(T) = (unsigned char)(def_temp);
+	*(T + 1) = (unsigned char)(def_temp >> 8);
 }
 
-static inline void int4store(char *T, uint32_t A) {
-  *(T) = (char)(A);
-  *(T + 1) = (char)(A >> 8);
-  *(T + 2) = (char)(A >> 16);
-  *(T + 3) = (char)(A >> 24);
+static inline void int4store(unsigned char *T, uint32_t A)
+{
+	*(T) = (unsigned char)(A);
+	*(T + 1) = (unsigned char)(A >> 8);
+	*(T + 2) = (unsigned char)(A >> 16);
+	*(T + 3) = (unsigned char)(A >> 24);
 }
 
-static inline void int7store(char *T, uint64_t A) {
-  *(T) = (char)(A);
-  *(T + 1) = (char)(A >> 8);
-  *(T + 2) = (char)(A >> 16);
-  *(T + 3) = (char)(A >> 24);
-  *(T + 4) = (char)(A >> 32);
-  *(T + 5) = (char)(A >> 40);
-  *(T + 6) = (char)(A >> 48);
+static inline void int7store(unsigned char *T, uint64_t A)
+{
+	*(T) = (unsigned char)(A);
+	*(T + 1) = (unsigned char)(A >> 8);
+	*(T + 2) = (unsigned char)(A >> 16);
+	*(T + 3) = (unsigned char)(A >> 24);
+	*(T + 4) = (unsigned char)(A >> 32);
+	*(T + 5) = (unsigned char)(A >> 40);
+	*(T + 6) = (unsigned char)(A >> 48);
 }
 
-static inline void int8store(char *T, uint64_t A) {
-  uint def_temp = (uint)A, def_temp2 = (uint)(A >> 32);
-  int4store(T, def_temp);
-  int4store(T + 4, def_temp2);
+static inline void int8store(unsigned char *T, uint64_t A)
+{
+	uint def_temp = (uint)A, def_temp2 = (uint)(A >> 32);
+	int4store(T, def_temp);
+	int4store(T + 4, def_temp2);
 }
 
-static inline void float4store(char *T, float A) {
-  *(T) = ((char *)&A)[3];
-  *((T) + 1) = (char)((char *)&A)[2];
-  *((T) + 2) = (char)((char *)&A)[1];
-  *((T) + 3) = (char)((char *)&A)[0];
+static inline void float4store(unsigned char *T, float A)
+{
+	*(T) = ((unsigned char *)&A)[3];
+	*((T) + 1) = (unsigned char)((unsigned char *)&A)[2];
+	*((T) + 2) = (unsigned char)((unsigned char *)&A)[1];
+	*((T) + 3) = (unsigned char)((unsigned char *)&A)[0];
 }
 
-static inline void float4get(float *V, const char *M) {
-  float def_temp;
-  ((char *)&def_temp)[0] = (M)[3];
-  ((char *)&def_temp)[1] = (M)[2];
-  ((char *)&def_temp)[2] = (M)[1];
-  ((char *)&def_temp)[3] = (M)[0];
-  (*V) = def_temp;
+static inline void float4get(float *V, const unsigned char *M)
+{
+	float def_temp;
+	((unsigned char *)&def_temp)[0] = (M)[3];
+	((unsigned char *)&def_temp)[1] = (M)[2];
+	((unsigned char *)&def_temp)[2] = (M)[1];
+	((unsigned char *)&def_temp)[3] = (M)[0];
+	(*V) = def_temp;
 }
 
-static inline void float8store(char *T, double V) {
-  *(T) = ((char *)&V)[7];
-  *((T) + 1) = (char)((char *)&V)[6];
-  *((T) + 2) = (char)((char *)&V)[5];
-  *((T) + 3) = (char)((char *)&V)[4];
-  *((T) + 4) = (char)((char *)&V)[3];
-  *((T) + 5) = (char)((char *)&V)[2];
-  *((T) + 6) = (char)((char *)&V)[1];
-  *((T) + 7) = (char)((char *)&V)[0];
+static inline void float8store(unsigned char *T, double V) {
+	*(T) = ((unsigned char *)&V)[7];
+	*((T) + 1) = (unsigned char)((unsigned char *)&V)[6];
+	*((T) + 2) = (unsigned char)((unsigned char *)&V)[5];
+	*((T) + 3) = (unsigned char)((unsigned char *)&V)[4];
+	*((T) + 4) = (unsigned char)((unsigned char *)&V)[3];
+	*((T) + 5) = (unsigned char)((unsigned char *)&V)[2];
+	*((T) + 6) = (unsigned char)((unsigned char *)&V)[1];
+	*((T) + 7) = (unsigned char)((unsigned char *)&V)[0];
 }
 
-static inline void float8get(double *V, const char *M) {
-  double def_temp;
-  ((char *)&def_temp)[0] = (M)[7];
-  ((char *)&def_temp)[1] = (M)[6];
-  ((char *)&def_temp)[2] = (M)[5];
-  ((char *)&def_temp)[3] = (M)[4];
-  ((char *)&def_temp)[4] = (M)[3];
-  ((char *)&def_temp)[5] = (M)[2];
-  ((char *)&def_temp)[6] = (M)[1];
-  ((char *)&def_temp)[7] = (M)[0];
-  (*V) = def_temp;
+static inline void float8get(double *V, const unsigned char *M)
+{
+	double def_temp;
+	((unsigned char *)&def_temp)[0] = (M)[7];
+	((unsigned char *)&def_temp)[1] = (M)[6];
+	((unsigned char *)&def_temp)[2] = (M)[5];
+	((unsigned char *)&def_temp)[3] = (M)[4];
+	((unsigned char *)&def_temp)[4] = (M)[3];
+	((unsigned char *)&def_temp)[5] = (M)[2];
+	((unsigned char *)&def_temp)[6] = (M)[1];
+	((unsigned char *)&def_temp)[7] = (M)[0];
+	(*V) = def_temp;
 }
 
-static inline void ushortget(uint16_t *V, const char *pM) {
-  *V = (uint16_t)(((uint16_t)((char)(pM)[1])) + ((uint16_t)((uint16_t)(pM)[0]) << 8));
-}
-static inline void shortget(int16_t *V, const char *pM) {
-  *V = (short)(((short)((char)(pM)[1])) + ((short)((short)(pM)[0]) << 8));
-}
-static inline void longget(int32_t *V, const char *pM) {
-  int32_t def_temp;
-  ((char *)&def_temp)[0] = (pM)[0];
-  ((char *)&def_temp)[1] = (pM)[1];
-  ((char *)&def_temp)[2] = (pM)[2];
-  ((char *)&def_temp)[3] = (pM)[3];
-  (*V) = def_temp;
-}
-static inline void ulongget(uint32_t *V, const char *pM) {
-  uint32_t def_temp;
-  ((char *)&def_temp)[0] = (pM)[0];
-  ((char *)&def_temp)[1] = (pM)[1];
-  ((char *)&def_temp)[2] = (pM)[2];
-  ((char *)&def_temp)[3] = (pM)[3];
-  (*V) = def_temp;
-}
-static inline void shortstore(char *T, int16_t A) {
-  uint def_temp = (uint)(A);
-  *(((char *)T) + 1) = (char)(def_temp);
-  *(((char *)T) + 0) = (char)(def_temp >> 8);
-}
-static inline void longstore(char *T, int32_t A) {
-  *(((char *)T) + 3) = ((A));
-  *(((char *)T) + 2) = (((A) >> 8));
-  *(((char *)T) + 1) = (((A) >> 16));
-  *(((char *)T) + 0) = (((A) >> 24));
+static inline void ushortget(uint16_t *V, const unsigned char *pM)
+{
+	*V = (uint16_t)(((uint16_t)((unsigned char)(pM)[1])) +
+		 ((uint16_t)((uint16_t)(pM)[0]) << 8));
 }
 
-static inline void floatget(float *V, const char *M) {
-  memcpy(V, (M), sizeof(float));
+static inline void shortget(int16_t *V, const unsigned char *pM)
+{
+	*V = (short)(((short)((unsigned char)(pM)[1])) +
+		 ((short)((short)(pM)[0]) << 8));
 }
 
-static inline void floatstore(char *T, float V) {
-  memcpy((T), (&V), sizeof(float));
+static inline void longget(int32_t *V, const unsigned char *pM)
+{
+	int32_t def_temp;
+	((unsigned char *)&def_temp)[0] = (pM)[0];
+	((unsigned char *)&def_temp)[1] = (pM)[1];
+	((unsigned char *)&def_temp)[2] = (pM)[2];
+	((unsigned char *)&def_temp)[3] = (pM)[3];
+	(*V) = def_temp;
 }
 
-static inline void doubleget(double *V, const char *M) {
-  memcpy(V, (M), sizeof(double));
+static inline void ulongget(uint32_t *V, const unsigned char *pM)
+{
+	uint32_t def_temp;
+	((unsigned char *)&def_temp)[0] = (pM)[0];
+	((unsigned char *)&def_temp)[1] = (pM)[1];
+	((unsigned char *)&def_temp)[2] = (pM)[2];
+	((unsigned char *)&def_temp)[3] = (pM)[3];
+	(*V) = def_temp;
 }
 
-static inline void doublestore(char *T, double V) {
-  memcpy((T), &V, sizeof(double));
+static inline void shortstore(unsigned char *T, int16_t A)
+{
+	uint def_temp = (uint)(A);
+	*(((unsigned char *)T) + 1) = (unsigned char)(def_temp);
+	*(((unsigned char *)T) + 0) = (unsigned char)(def_temp >> 8);
 }
 
-static inline void longlongget(int64_t *V, const char *M) {
-  memcpy(V, (M), sizeof(uint64_t));
+static inline void longstore(unsigned char *T, int32_t A)
+{
+	*(((unsigned char *)T) + 3) = ((A));
+	*(((unsigned char *)T) + 2) = (((A) >> 8));
+	*(((unsigned char *)T) + 1) = (((A) >> 16));
+	*(((unsigned char *)T) + 0) = (((A) >> 24));
 }
-static inline void longlongstore(char *T, int64_t V) {
-  memcpy((T), &V, sizeof(uint64_t));
+
+static inline void floatget(float *V, const unsigned char *M)
+{
+	memcpy(V, (M), sizeof(float));
+}
+
+static inline void floatstore(unsigned char *T, float V)
+{
+	memcpy((T), (&V), sizeof(float));
+}
+
+static inline void doubleget(double *V, const unsigned char *M)
+{
+	memcpy(V, (M), sizeof(double));
+}
+
+static inline void doublestore(unsigned char *T, double V)
+{
+	memcpy((T), &V, sizeof(double));
+}
+
+static inline void longlongget(int64_t *V, const unsigned char *M)
+{
+	memcpy(V, (M), sizeof(uint64_t));
+}
+
+static inline void longlongstore(unsigned char *T, int64_t V)
+{
+	memcpy((T), &V, sizeof(uint64_t));
+}
+
+static inline int32_t sint3korr(const unsigned char *p)
+{
+	return ((int32_t)(((p[2]) & 128)
+			 ? (((uint32_t)255L << 24) | (((uint32_t)p[2]) << 16)
+			 | (((uint32_t)p[1]) << 8) | ((uint32_t)p[0]))
+			 : (((uint32_t)p[2]) << 16) | (((uint32_t)p[1]) << 8)
+			 | ((uint32_t)p[0])));
+}
+
+static inline uint32_t uint3korr(const unsigned char *p)
+{
+	return (uint32_t)(((uint32_t)(p[0])) +
+		   (((uint32_t)(p[1])) << 8) +
+		   (((uint32_t)(p[2])) << 16));
+}
+
+static inline void int3store(unsigned char *p, uint32_t x)
+{
+	*(p) = (unsigned char)(x);
+	*(p + 1) = (unsigned char)(x >> 8);
+	*(p + 2) = (unsigned char)(x >> 16);
 }
 
 #else
@@ -288,40 +417,18 @@ static inline unsigned int get_length_size(unsigned long long num)
 	return 9;
 }
 
-static inline int32_t sint3korr(const char *p)
-{
-	return ((int32_t)(((p[2]) & 128)
-		   ? (((uint32_t)255L << 24) | (((uint32_t)p[2]) << 16)
-		   | (((uint32_t)p[1]) << 8) | ((uint32_t)p[0]))
-		   : (((uint32_t)p[2]) << 16) | (((uint32_t)p[1]) << 8)
-		   | ((uint32_t)p[0])));
-}
-
-static inline uint32_t uint3korr(const char *p)
-{
-	return (uint32_t)(((uint32_t)(p[0]))
-		   + (((uint32_t)(p[1])) << 8)
-		   + (((uint32_t)(p[2])) << 16));
-}
-
-static inline void int3store(char *p, uint32_t x)
-{
-	*(p) = (char)(x);
-	*(p + 1) = (char)(x >> 8);
-	*(p + 2) = (char)(x >> 16);
-}
-
 #ifdef __cplusplus
 extern "C"
 {
 #endif
 
 // decode encoded length integer within *end, move pos forward
-int decode_length_safe(unsigned long long *res, const char **pos, const char *end);
+int decode_length_safe(unsigned long long *res, const unsigned char **pos,
+					   const unsigned char *end);
 
 // decode encoded length string within *end, move pos forward
-int decode_string(const char **str, unsigned long long *len,
-				  const char **pos, const char *end);
+int decode_string(const unsigned char **str, unsigned long long *len,
+				  const unsigned char **pos, const unsigned char *end);
 
 #ifdef __cplusplus
 }
diff --git a/src/protocol/mysql_parser.c b/src/protocol/mysql_parser.c
index 9d54bdaf..54959ab0 100644
--- a/src/protocol/mysql_parser.c
+++ b/src/protocol/mysql_parser.c
@@ -148,8 +148,8 @@ static int parse_base_packet(const void *buf, size_t len, mysql_parser_t *parser
 // 1:0xFF|2:err_no|1:#|5:server_state|0-512:err_msg
 static int parse_error_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	if (p + 9 > buf_end)
 		return -2;
@@ -160,11 +160,11 @@ static int parse_error_packet(const void *buf, size_t len, mysql_parser_t *parse
 	if (*p == '#')
 	{
 		p += 1;
-		parser->net_state_offset = p - (const char *)buf;
+		parser->net_state_offset = p - (const unsigned char *)buf;
 		p += MYSQL_STATE_LENGTH;
 
 		size_t msg_len = len - parser->offset - 9;
-		parser->err_msg_offset = p - (const char *)buf;
+		parser->err_msg_offset = p - (const unsigned char *)buf;
 		parser->err_msg_len = msg_len;
 	} else {
 		parser->err_msg_offset = (size_t)-1;
@@ -180,8 +180,8 @@ static int parse_error_packet(const void *buf, size_t len, mysql_parser_t *parse
 // 1:0x00|1-9:affect_row|1-9:insert_id|2:server_status|2:warning_count|0-n:server_msg
 static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	unsigned long long affected_rows, insert_id, info_len;
 	int server_status;
@@ -215,9 +215,10 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 		parser->info_len = 0;
 	}
 
-	parser->info_offset = p - (const char *)buf;
+	parser->info_offset = p - (const unsigned char *)buf;
 	parser->offset += parser->info_offset + parser->info_len;
-	parser->affected_rows = (affected_rows == (unsigned long long)-1) ? 0 : affected_rows;
+	parser->affected_rows = (affected_rows == (unsigned long long)-1) ?
+											   0 : affected_rows;
 	parser->insert_id = (insert_id == (unsigned long long)-1) ? 0 : insert_id;
 	parser->server_status = server_status;
 	parser->warning_count = warning_count;
@@ -236,8 +237,8 @@ static int parse_ok_packet(const void *buf, size_t len, mysql_parser_t *parser)
 // 1:0xfe|2:warnings|2:status_flag
 static int parse_eof_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	if (p + 5 > buf_end)
 		return -2;
@@ -258,14 +259,15 @@ static int parse_eof_packet(const void *buf, size_t len, mysql_parser_t *parser)
 
 static int parse_field_eof_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	if (p + 5 > buf_end)
 		return -2;
 
 	parser->offset += 5;
-	parser->current_result_set->rows_begin_offset = p + 5 - (const char *)buf;
+	parser->current_result_set->rows_begin_offset = p + 5 -
+													(const unsigned char *)buf;
 	parser->parse = parse_row_packet;
 	return 0;
 }
@@ -285,30 +287,31 @@ static int parse_local_inline(const void *buf, size_t len, mysql_parser_t *parse
 // NULL as 0xfb, or a length-encoded-string
 static int parse_row_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	unsigned long long cell_len;
-	const char *cell_data;
+	const unsigned char *cell_data;
 
 	size_t i;
 
-	if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_ERROR)
+	if (*p == MYSQL_PACKET_HEADER_ERROR)
 	{
 		parser->parse = parse_error_packet;
 		return 0;
 	}
 
-	if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_EOF)
+	if (*p == MYSQL_PACKET_HEADER_EOF)
 	{
 		parser->parse = parse_eof_packet;
-		parser->current_result_set->rows_end_offset = p - (const char *)buf;
+		parser->current_result_set->rows_end_offset = p -
+													(const unsigned char *)buf;
 		return 0;
 	}
 
 	for (i = 0; i < parser->current_result_set->field_count; i++)
 	{
-		if (*(const unsigned char *)p == MYSQL_PACKET_HEADER_NULL)
+		if (*p == MYSQL_PACKET_HEADER_NULL)
 		{
 			p++;
 		} else {
@@ -321,14 +324,14 @@ static int parse_row_packet(const void *buf, size_t len, mysql_parser_t *parser)
 		return -2;
 
 	parser->current_result_set->row_count++;
-	parser->offset = p - (const char *)buf;
+	parser->offset = p - (const unsigned char *)buf;
 	return 0;
 }
 
 static int parse_field_count(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	unsigned long long field_count;
 	struct __mysql_result_set *result_set;
@@ -361,7 +364,7 @@ static int parse_field_count(const void *buf, size_t len, mysql_parser_t *parser
 		parser->result_set_count++;
 
 		parser->parse = parse_column_def_packet;
-		parser->offset = p - (const char *)buf;
+		parser->offset = p - (const unsigned char *)buf;
 	} else {
 		parser->parse = parse_ok_packet;
 	}
@@ -373,11 +376,11 @@ static int parse_field_count(const void *buf, size_t len, mysql_parser_t *parser
 // 2:charsetnr|4:length|1:type|2:flags|1:decimals|1:0x00|1:0x00|n:str(if COM_FIELD_LIST)
 static int parse_column_def_packet(const void *buf, size_t len, mysql_parser_t *parser)
 {
-	const char *p = (const char *)buf + parser->offset;
-	const char *buf_end = (const char *)buf + len;
+	const unsigned char *p = (const unsigned char *)buf + parser->offset;
+	const unsigned char *buf_end = (const unsigned char *)buf + len;
 
 	int flag = 0;
-	const char *str;
+	const unsigned char *str;
 	unsigned long long str_len;
 	mysql_field_t *field = (mysql_field_t *)malloc(sizeof(mysql_field_t));
 
@@ -387,32 +390,32 @@ static int parse_column_def_packet(const void *buf, size_t len, mysql_parser_t *
 	do {
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->catalog_offset = str - (const char *)buf;
+		field->catalog_offset = str - (const unsigned char *)buf;
 		field->catalog_length = str_len;
 
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->db_offset = str - (const char *)buf;
+		field->db_offset = str - (const unsigned char *)buf;
 		field->db_length = str_len;
 
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->table_offset = str - (const char *)buf;
+		field->table_offset = str - (const unsigned char *)buf;
 		field->table_length = str_len;
 
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->org_table_offset = str - (const char *)buf;
+		field->org_table_offset = str - (const unsigned char *)buf;
 		field->org_table_length = str_len;
 
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->name_offset = str - (const char *)buf;
+		field->name_offset = str - (const unsigned char *)buf;
 		field->name_length = str_len;
 
 		if (decode_string(&str, &str_len, &p, buf_end) == 0)
 			break;
-		field->org_name_offset = str - (const char *)buf;
+		field->org_name_offset = str - (const unsigned char *)buf;
 		field->org_name_length = str_len;
 
 		// the rest needs at least 13
@@ -422,7 +425,7 @@ static int parse_column_def_packet(const void *buf, size_t len, mysql_parser_t *
 		p++; // length of the following fields (always 0x0c)
 		field->charsetnr = uint2korr(p);
 		field->length = uint4korr(p + 2);
-		field->data_type = *((const unsigned char *)p + 6);
+		field->data_type = *(p + 6);
 		field->flags = uint2korr(p + 7);
 		field->decimals = (int)p[9];
 		p += 12;
@@ -432,7 +435,7 @@ static int parse_column_def_packet(const void *buf, size_t len, mysql_parser_t *
 		{
 			if (decode_string(&str, &str_len, &p, buf_end) == 0)
 				break;
-			field->def_offset = str - (const char *)buf;
+			field->def_offset = str - (const unsigned char *)buf;
 			field->def_length = str_len;
 		} else {
 			field->def_offset = (size_t)-1;
@@ -450,7 +453,7 @@ static int parse_column_def_packet(const void *buf, size_t len, mysql_parser_t *
 	//parser->fields.emplace_back(std::move(field));
 	parser->current_result_set->fields[parser->current_field_count] = field;
 
-	parser->offset = p - (const char *)buf;
+	parser->offset = p - (const unsigned char *)buf;
 	if (++parser->current_field_count == parser->current_result_set->field_count)
 		parser->parse = parse_field_eof_packet;