diff --git a/src/common/classes/fb_string.cpp b/src/common/classes/fb_string.cpp
index 40a2a5c1f4..b9eac15bc7 100644
--- a/src/common/classes/fb_string.cpp
+++ b/src/common/classes/fb_string.cpp
@@ -68,7 +68,7 @@ namespace {
 				m[c >> 3] |= (1 << (c & 7));
 			}
 		}
-		inline bool Contains(const char c) {
+		inline bool Contains(const char c) const {
 			return m[c >> 3] & (1 << (c & 7));
 		}
 	};
@@ -91,10 +91,12 @@ namespace Firebird {
 				 const_pointer p2, size_type n2)
 	{
 		// CVC: npos must be maximum size_type value for all platforms.
-		// fb_assert(npos - n1 > n2 && n1 + n2 <= max_length());
-		checkLength(n1);
-		checkLength(n2);
-		checkLength(n1 + n2);
+		// fb_assert(n2 < npos - n1 && n1 + n2 <= max_length());
+		if (n2 > npos - n1)
+		{
+			Firebird::fatal_exception::raise("String length overflow");
+		}
+		// checkLength(n1 + n2); redundant: initialize() will check.
 		initialize(n1 + n2);
 		memcpy(stringBuffer, p1, n1);
 		memcpy(stringBuffer + n1, p2, n2);
@@ -104,6 +106,18 @@ namespace Firebird {
 		initialize(sizeL);
 		memset(stringBuffer, c, sizeL);
 	}
+	
+	AbstractString::size_type AbstractString::copy_to(pointer destination,
+		size_type bufsize) const
+	{
+		if (!destination || !bufsize)
+			return 0;
+
+		const size_type copy_len = length() < bufsize ? length() : bufsize - 1;
+		memcpy(destination, stringBuffer, copy_len);
+		destination[copy_len] = 0;
+		return copy_len;
+	}
 
 	void AbstractString::AdjustRange(size_type length, size_type& pos, size_type& n) {
 		if (pos == npos) {
@@ -213,7 +227,7 @@ namespace Firebird {
 	}
 
 	AbstractString::size_type AbstractString::find_first_of(const_pointer s, size_type pos, size_type n) const {
-		strBitMask sm(s, n);
+		const strBitMask sm(s, n);
 		const_pointer p = &c_str()[pos];
 		while (pos < length()) {
 			if (sm.Contains(*p++)) {
@@ -225,7 +239,7 @@ namespace Firebird {
 	}
 
 	AbstractString::size_type AbstractString::find_last_of(const_pointer s, size_type pos, size_type n) const {
-		strBitMask sm(s, n);
+		const strBitMask sm(s, n);
 		int lpos = length() - 1;
 		if (static_cast<int>(pos) < lpos && pos != npos) {
 			lpos = pos;
@@ -241,7 +255,7 @@ namespace Firebird {
 	}
 
 	AbstractString::size_type AbstractString::find_first_not_of(const_pointer s, size_type pos, size_type n) const {
-		strBitMask sm(s, n);
+		const strBitMask sm(s, n);
 		const_pointer p = &c_str()[pos];
 		while (pos < length()) {
 			if (! sm.Contains(*p++)) {
@@ -253,7 +267,7 @@ namespace Firebird {
 	}
 
 	AbstractString::size_type AbstractString::find_last_not_of(const_pointer s, size_type pos, size_type n) const {
-		strBitMask sm(s, n);
+		const strBitMask sm(s, n);
 		int lpos = length() - 1;
 		if (static_cast<int>(pos) < lpos && pos != npos) {
 			lpos = pos;
@@ -315,7 +329,7 @@ extern "C" {
 	}
 
 	void AbstractString::baseTrim(TrimType WhereTrim, const_pointer ToTrim) {
-		strBitMask sm(ToTrim, strlen(ToTrim));
+		const strBitMask sm(ToTrim, strlen(ToTrim));
 		const_pointer b = c_str();
 		const_pointer e = &c_str()[length() - 1];
 		if (WhereTrim != TrimRight) {
@@ -334,7 +348,7 @@ extern "C" {
 				--e;
 			}
 		}
-		size_type NewLength = e - b + 1;
+		const size_type NewLength = e - b + 1;
 
 		if (NewLength == length())
 			return;
diff --git a/src/include/fb_string.h b/src/include/fb_string.h
index 7734a392f6..c3a31834ed 100644
--- a/src/include/fb_string.h
+++ b/src/include/fb_string.h
@@ -53,17 +53,20 @@ namespace Firebird
 		typedef const_pointer const_iterator;
 		static const size_type npos;
 		enum {INLINE_BUFFER_SIZE = 32, INIT_RESERVE = 16/*, KEEP_SIZE = 512*/};
+		
 	protected:
 		typedef USHORT internal_size_type; // 16 bits!
 		char_type inlineBuffer[INLINE_BUFFER_SIZE];
 		char_type* stringBuffer;
 		internal_size_type stringLength, bufferSize;
+		
 	private:
 		inline void checkPos(size_type pos) const {
 			if (pos >= length()) {
 				fatal_exception::raise("Firebird::string - pos out of range");
 			}
 		}
+		
 		static inline void checkLength(size_type len) {
 			if (len > max_length()) {
 				fatal_exception::raise("Firebird::string - length exceeds predefined limit");
@@ -187,6 +190,7 @@ namespace Firebird
 		enum TrimType {TrimLeft, TrimRight, TrimBoth};
 
 		void baseTrim(TrimType WhereTrim, const_pointer ToTrim);
+		
 	public:
 		inline const_pointer c_str() const {
 			return stringBuffer;
@@ -194,15 +198,26 @@ namespace Firebird
 		inline size_type length() const {
 			return stringLength;
 		}
+		// Call it only when you have worked with at() or operator[]
+		// in case a null ASCII was inserted in the middle of the string.
+		inline size_type recalculate_length()
+		{
+		    stringLength = strlen(stringBuffer);
+		    return stringLength;
+		}
+		
 		void reserve(size_type n = 0);
 		void resize(size_type n, char_type c = ' ');
 
-		inline size_type copy(pointer s, size_type n, size_type pos = 0) const {
+		inline size_type copy_from(pointer s, size_type n, size_type pos = 0) const
+		{
 			AdjustRange(length(), pos, n);
 			memcpy(s, c_str() + pos, n);
 			return n;
 		}
 
+		size_type copy_to(pointer destination, size_type bufsize) const;
+		
 /*		inline void swap(AbstractString& str) {
 			Storage *tmp = StringData;
 			StringData = str.StringData;
@@ -253,9 +268,7 @@ namespace Firebird
 			return find_first_not_of(s, pos, strlen(s));
 		}
 		inline size_type find_first_not_of(char_type c, size_type pos = 0) const {
-			char s[2];
-			s[0] = c;
-			s[1] = 0;
+			const char s[2] = {c, 0};
 			return find_first_not_of(s, pos, 1);
 		}
 		inline size_type find_last_not_of(const AbstractString& str, size_type pos = npos) const {
@@ -266,9 +279,7 @@ namespace Firebird
 			return find_last_not_of(s, pos, strlen(s));
 		}
 		inline size_type find_last_not_of(char_type c, size_type pos = npos) const {
-			char s[2];
-			s[0] = c;
-			s[1] = 0;
+			const char s[2] = {c, 0};
 			return find_last_not_of(s, pos, 1);
 		}
 
@@ -507,7 +518,7 @@ namespace Firebird
 			return it;
 		}
 		inline iterator erase(iterator first, iterator last) {
-			erase(first - c_str(), last-first);
+			erase(first - c_str(), last - first);
 			return first;
 		}