ICE-6991 - Add support for unicode escape sequences

4 files changed, 851 insertions, 454 deletions

diff --git a/cpp/src/Slice/PythonUtil.cpp b/cpp/src/Slice/PythonUtil.cpp
index 220e521d85d..92f657e8221 100644
--- a/cpp/src/Slice/PythonUtil.cpp
+++ b/cpp/src/Slice/PythonUtil.cpp
@@ -13,6 +13,7 @@
 #include <IceUtil/IceUtil.h>
 #include <IceUtil/StringUtil.h>
 #include <IceUtil/InputUtil.h>
+#include <IceUtil/Unicode.h>
 #include <climits>
 #include <iterator>
 
@@ -1879,68 +1880,138 @@ Slice::Python::CodeVisitor::writeConstantValue(const TypePtr& type, const Syntax
 
                 _out << "\"";                                       // Opening "
 
-                for(string::const_iterator c = value.begin(); c != value.end(); ++c)
+                for(size_t i = 0; i < value.size();)
                 {
-                    switch(*c)
+                    char c = value[i];
+                    switch(c)
                     {
-                    case '"':
-                    {
-                        _out << "\\\"";
-                        break;
-                    }
-                    case '\\':
-                    {
-                        _out << "\\\\";
-                        break;
-                    }
-                    case '\r':
-                    {
-                        _out << "\\r";
-                        break;
-                    }
-                    case '\n':
-                    {
-                        _out << "\\n";
-                        break;
-                    }
-                    case '\t':
-                    {
-                        _out << "\\t";
-                        break;
-                    }
-                    case '\b':
-                    {
-                        _out << "\\b";
-                        break;
-                    }
-                    case '\f':
-                    {
-                        _out << "\\f";
-                        break;
-                    }
-                    default:
-                    {
-                        if(charSet.find(*c) == charSet.end())
+                        case '"':
                         {
-                            unsigned char uc = *c;              // Char may be signed, so make it positive.
-                            stringstream s;
-                            s << "\\";                          // Print as octal if not in basic source character set.
-                            s.flags(ios_base::oct);
-                            s.width(3);
-                            s.fill('0');
-                            s << static_cast<unsigned>(uc);
-                            _out << s.str();
+                            _out << "\\\"";
+                            break;
                         }
-                        else
+                        case '\\':
                         {
-                            _out << *c;                         // Print normally if in basic source character set.
+                            string s = "\\";
+                            size_t j = i + 1;
+                            for(; j < value.size(); ++j)
+                            {
+                                if(value[j] != '\\')
+                                {
+                                    break;
+                                }
+                                s += "\\";
+                            }
+                            
+                            //
+                            // An even number of slash \ will escape the backslash and
+                            // the codepoint will be interpreted as its charaters
+                            //
+                            // \\u00000041  - ['\\', 'u', '0', '0', '0', '0', '0', '0', '4', '1']
+                            // \\\u00000041 - ['\\', 'A'] (41 is the codepoint for 'A')
+                            //
+                            if(s.size() % 2 != 0 && (value[j] == 'U' || value[j] == 'u'))
+                            {
+                                //
+                                // Convert codepoint to UTF8 bytes and write the escaped bytes
+                                //
+                                _out << s.substr(0, s.size() - 1);
+                                
+                                size_t sz = value[j] == 'U' ? 8 : 4;
+                                string codepoint = value.substr(j + 1, sz);
+                                assert(codepoint.size() ==  sz);
+
+                                IceUtil::Int64 v = IceUtilInternal::strToInt64(codepoint.c_str(), 0, 16);
+                                
+                                vector<unsigned int> u32buffer;
+                                u32buffer.push_back(v);
+                                
+                                vector<unsigned char> u8buffer;
+                                IceUtilInternal::ConversionResult result = convertUTF32ToUTF8(u32buffer, u8buffer, IceUtil::lenientConversion);
+                                switch(result)
+                                {
+                                    case conversionOK:
+                                        break;
+                                    case sourceExhausted:
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__, "string source exhausted");
+                                    case sourceIllegal:
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__, "string source illegal");
+                                    default:
+                                    {
+                                        assert(0);
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__);
+                                    }
+                                }
+                                
+                                ostringstream s;
+                                for(vector<unsigned char>::const_iterator q = u8buffer.begin(); q != u8buffer.end(); ++q)
+                                {
+                                    s << "\\";
+                                    s.fill('0');
+                                    s.width(3);
+                                    s << oct;
+                                    s << static_cast<unsigned int>(*q);
+                                }
+                                _out << s.str();
+                                
+                                i = j + 1 + sz;
+                            }
+                            else
+                            {
+                                _out << s;
+                                i = j;
+                            }
+                            continue;
+                        }
+                        case '\r':
+                        {
+                            _out << "\\r";
+                            break;
+                        }
+                        case '\n':
+                        {
+                            _out << "\\n";
+                            break;
+                        }
+                        case '\t':
+                        {
+                            _out << "\\t";
+                            break;
+                        }
+                        case '\b':
+                        {
+                            _out << "\\b";
+                            break;
+                        }
+                        case '\f':
+                        {
+                            _out << "\\f";
+                            break;
+                        }
+                        default:
+                        {
+                            if(charSet.find(c) == charSet.end())
+                            {
+                                unsigned char uc = c;               // Char may be signed, so make it positive.
+                                stringstream s;
+                                s << "\\";                          // Print as octal if not in basic source character set.
+                                s.flags(ios_base::oct);
+                                s.width(3);
+                                s.fill('0');
+                                s << static_cast<unsigned>(uc);
+                                _out << s.str();
+                            }
+                            else
+                            {
+                                _out << c;                          // Print normally if in basic source character set.
+                            }
+                            break;
                         }
-                        break;
-                    }
                     }
+                    ++i;
                 }
 
-                _out << "\"";                                   // Closing "
+                _out << "\"";                                       // Closing "
                 break;
             }
             case Slice::Builtin::KindObject:
diff --git a/cpp/src/Slice/RubyUtil.cpp b/cpp/src/Slice/RubyUtil.cpp
index 3e6fe7557ac..fbed4764bbe 100644
--- a/cpp/src/Slice/RubyUtil.cpp
+++ b/cpp/src/Slice/RubyUtil.cpp
@@ -12,6 +12,7 @@
 #include <Slice/Util.h>
 #include <IceUtil/Functional.h>
 #include <IceUtil/InputUtil.h>
+#include <IceUtil/Unicode.h>
 #include <iterator>
 
 using namespace std;
@@ -1470,65 +1471,134 @@ Slice::Ruby::CodeVisitor::writeConstantValue(const TypePtr& type, const SyntaxTr
 
                 _out << "\"";                                      // Opening "
 
-                for(string::const_iterator c = value.begin(); c != value.end(); ++c)
+                for(size_t i = 0; i < value.size();)
                 {
-                    switch(*c)
+                    char c = value[i];
+                    switch(c)
                     {
-                    case '"':
-                    {
-                        _out << "\\\"";
-                        break;
-                    }
-                    case '\\':
-                    {
-                        _out << "\\\\";
-                        break;
-                    }
-                    case '\r':
-                    {
-                        _out << "\\r";
-                        break;
-                    }
-                    case '\n':
-                    {
-                        _out << "\\n";
-                        break;
-                    }
-                    case '\t':
-                    {
-                        _out << "\\t";
-                        break;
-                    }
-                    case '\b':
-                    {
-                        _out << "\\b";
-                        break;
-                    }
-                    case '\f':
-                    {
-                        _out << "\\f";
-                        break;
-                    }
-                    default:
-                    {
-                        if(charSet.find(*c) == charSet.end())
+                        case '"':
                         {
-                            unsigned char uc = *c;              // Char may be signed, so make it positive.
-                            stringstream s;
-                            s << "\\";                          // Print as octal if not in basic source character set.
-                            s.flags(ios_base::oct);
-                            s.width(3);
-                            s.fill('0');
-                            s << static_cast<unsigned>(uc);
-                            _out << s.str();
+                            _out << "\\\"";
+                            break;
                         }
-                        else
+                        case '\\':
                         {
-                            _out << *c;                         // Print normally if in basic source character set.
+                            string s = "\\";
+                            size_t j = i + 1;
+                            for(; j < value.size(); ++j)
+                            {
+                                if(value[j] != '\\')
+                                {
+                                    break;
+                                }
+                                s += "\\";
+                            }
+                            
+                            //
+                            // An even number of slash \ will escape the backslash and
+                            // the codepoint will be interpreted as its charaters
+                            //
+                            // \\u00000041  - ['\\', 'u', '0', '0', '0', '0', '0', '0', '4', '1']
+                            // \\\u00000041 - ['\\', 'A'] (41 is the codepoint for 'A')
+                            //
+                            if(s.size() % 2 != 0 && (value[j] == 'U' || value[j] == 'u'))
+                            {
+                                //
+                                // Convert codepoint to UTF8 bytes and write the escaped bytes
+                                //
+                                _out << s.substr(0, s.size() - 1);
+                                
+                                size_t sz = value[j] == 'U' ? 8 : 4;
+                                string codepoint = value.substr(j + 1, sz);
+                                assert(codepoint.size() == sz);
+                                IceUtil::Int64 v = IceUtilInternal::strToInt64(codepoint.c_str(), 0, 16);
+                                
+                                vector<unsigned int> u32buffer;
+                                u32buffer.push_back(v);
+                                
+                                vector<unsigned char> u8buffer;
+                                IceUtilInternal::ConversionResult result = convertUTF32ToUTF8(u32buffer, u8buffer, IceUtil::lenientConversion);
+                                switch(result)
+                                {
+                                    case conversionOK:
+                                        break;
+                                    case sourceExhausted:
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__, "string source exhausted");
+                                    case sourceIllegal:
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__, "string source illegal");
+                                    default:
+                                    {
+                                        assert(0);
+                                        throw IceUtil::IllegalConversionException(__FILE__, __LINE__);
+                                    }
+                                }
+                                
+                                ostringstream s;
+                                for(vector<unsigned char>::const_iterator q = u8buffer.begin(); q != u8buffer.end(); ++q)
+                                {
+                                    s << "\\";
+                                    s.fill('0');
+                                    s.width(3);
+                                    s << oct;
+                                    s << static_cast<unsigned int>(*q);
+                                }
+                                _out << s.str();
+                                
+                                i = j + 1 + sz;
+                            }
+                            else
+                            {
+                                _out << s;
+                                i = j;
+                            }
+                            continue;
+                        }
+                        case '\r':
+                        {
+                            _out << "\\r";
+                            break;
+                        }
+                        case '\n':
+                        {
+                            _out << "\\n";
+                            break;
+                        }
+                        case '\t':
+                        {
+                            _out << "\\t";
+                            break;
+                        }
+                        case '\b':
+                        {
+                            _out << "\\b";
+                            break;
+                        }
+                        case '\f':
+                        {
+                            _out << "\\f";
+                            break;
+                        }
+                        default:
+                        {
+                            if(charSet.find(c) == charSet.end())
+                            {
+                                unsigned char uc = c;              // Char may be signed, so make it positive.
+                                stringstream s;
+                                s << "\\";                         // Print as octal if not in basic source character set.
+                                s.flags(ios_base::oct);
+                                s.width(3);
+                                s.fill('0');
+                                s << static_cast<unsigned>(uc);
+                                _out << s.str();
+                            }
+                            else
+                            {
+                                _out << c;                         // Print normally if in basic source character set.
+                            }
+                            break;
                         }
-                        break;
-                    }
                     }
+                    ++i;
                 }
 
                 _out << "\"";                                   // Closing "
@@ -1635,6 +1705,7 @@ Slice::Ruby::CodeVisitor::collectExceptionMembers(const ExceptionPtr& p, MemberI
 void
 Slice::Ruby::generate(const UnitPtr& un, bool all, bool checksum, const vector<string>& includePaths, Output& out)
 {
+    out <<"# encoding: utf-8";
     out << nl << "require 'Ice'";
 
     if(!all)
diff --git a/cpp/src/Slice/Scanner.cpp b/cpp/src/Slice/Scanner.cpp
index 0a4fdad538d..fc2fc290dac 100644
--- a/cpp/src/Slice/Scanner.cpp
+++ b/cpp/src/Slice/Scanner.cpp
@@ -29,7 +29,7 @@
 #define FLEX_SCANNER
 #define YY_FLEX_MAJOR_VERSION 2
 #define YY_FLEX_MINOR_VERSION 5
-#define YY_FLEX_SUBMINOR_VERSION 35
+#define YY_FLEX_SUBMINOR_VERSION 39
 #if YY_FLEX_SUBMINOR_VERSION > 0
 #define FLEX_BETA
 #endif
@@ -74,7 +74,6 @@ typedef int flex_int32_t;
 typedef unsigned char flex_uint8_t; 
 typedef unsigned short int flex_uint16_t;
 typedef unsigned int flex_uint32_t;
-#endif /* ! C99 */
 
 /* Limits of integral types. */
 #ifndef INT8_MIN
@@ -105,6 +104,8 @@ typedef unsigned int flex_uint32_t;
 #define UINT32_MAX             (4294967295U)
 #endif
 
+#endif /* ! C99 */
+
 #endif /* ! FLEXINT_H */
 
 #ifdef __cplusplus
@@ -161,7 +162,15 @@ typedef unsigned int flex_uint32_t;
 
 /* Size of default input buffer. */
 #ifndef YY_BUF_SIZE
+#ifdef __ia64__
+/* On IA-64, the buffer size is 16k, not 8k.
+ * Moreover, YY_BUF_SIZE is 2*YY_READ_BUF_SIZE in the general case.
+ * Ditto for the __ia64__ case accordingly.
+ */
+#define YY_BUF_SIZE 32768
+#else
 #define YY_BUF_SIZE 16384
+#endif /* __ia64__ */
 #endif
 
 /* The state buf must be large enough to hold one state per character in the main buffer.
@@ -173,7 +182,12 @@ typedef unsigned int flex_uint32_t;
 typedef struct yy_buffer_state *YY_BUFFER_STATE;
 #endif
 
-extern int slice_leng;
+#ifndef YY_TYPEDEF_YY_SIZE_T
+#define YY_TYPEDEF_YY_SIZE_T
+typedef size_t yy_size_t;
+#endif
+
+extern yy_size_t slice_leng;
 
 extern FILE *slice_in, *slice_out;
 
@@ -182,6 +196,7 @@ extern FILE *slice_in, *slice_out;
 #define EOB_ACT_LAST_MATCH 2
 
     #define YY_LESS_LINENO(n)
+    #define YY_LINENO_REWIND_TO(ptr)
     
 /* Return all but the first "n" matched characters back to the input stream. */
 #define yyless(n) \
@@ -199,11 +214,6 @@ extern FILE *slice_in, *slice_out;
 
 #define unput(c) yyunput( c, (yytext_ptr)  )
 
-#ifndef YY_TYPEDEF_YY_SIZE_T
-#define YY_TYPEDEF_YY_SIZE_T
-typedef size_t yy_size_t;
-#endif
-
 #ifndef YY_STRUCT_YY_BUFFER_STATE
 #define YY_STRUCT_YY_BUFFER_STATE
 struct yy_buffer_state
@@ -221,7 +231,7 @@ struct yy_buffer_state
 	/* Number of characters read into yy_ch_buf, not including EOB
 	 * characters.
 	 */
-	int yy_n_chars;
+	yy_size_t yy_n_chars;
 
 	/* Whether we "own" the buffer - i.e., we know we created it,
 	 * and can realloc() it to grow it, and should free() it to
@@ -291,8 +301,8 @@ static YY_BUFFER_STATE * yy_buffer_stack = 0; /**< Stack as an array. */
 
 /* yy_hold_char holds the character lost when slice_text is formed. */
 static char yy_hold_char;
-static int yy_n_chars;		/* number of characters read into yy_ch_buf */
-int slice_leng;
+static yy_size_t yy_n_chars;		/* number of characters read into yy_ch_buf */
+yy_size_t slice_leng;
 
 /* Points to current character in buffer. */
 static char *yy_c_buf_p = (char *) 0;
@@ -320,7 +330,7 @@ static void slice__init_buffer (YY_BUFFER_STATE b,FILE *file  );
 
 YY_BUFFER_STATE slice__scan_buffer (char *base,yy_size_t size  );
 YY_BUFFER_STATE slice__scan_string (yyconst char *yy_str  );
-YY_BUFFER_STATE slice__scan_bytes (yyconst char *bytes,int len  );
+YY_BUFFER_STATE slice__scan_bytes (yyconst char *bytes,yy_size_t len  );
 
 void *slice_alloc (yy_size_t  );
 void *slice_realloc (void *,yy_size_t  );
@@ -352,7 +362,7 @@ void slice_free (void *  );
 
 /* Begin user sect3 */
 
-#define slice_wrap(n) 1
+#define slice_wrap() 1
 #define YY_SKIP_YYWRAP
 
 typedef unsigned char YY_CHAR;
@@ -558,6 +568,8 @@ char *slice_text;
 #include <Slice/Grammar.h>
 #include <IceUtil/InputUtil.h>
 
+#include <iomanip>
+
 #include <stdlib.h>
 #include <math.h>
 
@@ -620,7 +632,7 @@ int checkKeyword(string&);
 
 
 
-#line 623 "lex.yy.c"
+#line 635 "lex.yy.c"
 
 #define INITIAL 0
 #define BOMSCAN 1
@@ -661,7 +673,7 @@ FILE *slice_get_out (void );
 
 void slice_set_out  (FILE * out_str  );
 
-int slice_get_leng (void );
+yy_size_t slice_get_leng (void );
 
 char *slice_get_text (void );
 
@@ -703,7 +715,12 @@ static int input (void );
 
 /* Amount of stuff to slurp up with each read. */
 #ifndef YY_READ_BUF_SIZE
+#ifdef __ia64__
+/* On IA-64, the buffer size is 16k, not 8k */
+#define YY_READ_BUF_SIZE 16384
+#else
 #define YY_READ_BUF_SIZE 8192
+#endif /* __ia64__ */
 #endif
 
 /* Copy whatever the last rule matched to the standard output. */
@@ -722,7 +739,7 @@ static int input (void );
 	if ( YY_CURRENT_BUFFER_LVALUE->yy_is_interactive ) \
 		{ \
 		int c = '*'; \
-		unsigned n; \
+		size_t n; \
 		for ( n = 0; n < max_size && \
 			     (c = getc( slice_in )) != EOF && c != '\n'; ++n ) \
 			buf[n] = (char) c; \
@@ -807,11 +824,6 @@ YY_DECL
 	register char *yy_cp, *yy_bp;
 	register int yy_act;
     
-#line 92 "Scanner.l"
-
-
-#line 813 "lex.yy.c"
-
 	if ( !(yy_init) )
 		{
 		(yy_init) = 1;
@@ -838,6 +850,12 @@ YY_DECL
 		slice__load_buffer_state( );
 		}
 
+	{
+#line 94 "Scanner.l"
+
+
+#line 857 "lex.yy.c"
+
 	while ( 1 )		/* loops until end-of-file is reached */
 		{
 		yy_cp = (yy_c_buf_p);
@@ -855,7 +873,7 @@ YY_DECL
 yy_match:
 		do
 			{
-			register YY_CHAR yy_c = yy_ec[YY_SC_TO_UI(*yy_cp)];
+			register YY_CHAR yy_c = yy_ec[YY_SC_TO_UI(*yy_cp)] ;
 			if ( yy_accept[yy_current_state] )
 				{
 				(yy_last_accepting_state) = yy_current_state;
@@ -895,7 +913,7 @@ case 1:
 (yy_c_buf_p) = yy_cp -= 1;
 YY_DO_BEFORE_ACTION; /* set up slice_text again */
 YY_RULE_SETUP
-#line 94 "Scanner.l"
+#line 96 "Scanner.l"
 {
     if(unit->scanPosition(slice_text))
     {
@@ -906,10 +924,11 @@ YY_RULE_SETUP
 case 2:
 /* rule 2 can match eol */
 *yy_cp = (yy_hold_char); /* undo effects of setting up slice_text */
+YY_LINENO_REWIND_TO(yy_cp - 1);
 (yy_c_buf_p) = yy_cp -= 1;
 YY_DO_BEFORE_ACTION; /* set up slice_text again */
 YY_RULE_SETUP
-#line 101 "Scanner.l"
+#line 103 "Scanner.l"
 {
     if(unit->scanPosition(slice_text))
     {
@@ -922,7 +941,7 @@ case 3:
 (yy_c_buf_p) = yy_cp -= 1;
 YY_DO_BEFORE_ACTION; /* set up slice_text again */
 YY_RULE_SETUP
-#line 108 "Scanner.l"
+#line 110 "Scanner.l"
 {
     if(unit->scanPosition(slice_text))
     {
@@ -933,10 +952,11 @@ YY_RULE_SETUP
 case 4:
 /* rule 4 can match eol */
 *yy_cp = (yy_hold_char); /* undo effects of setting up slice_text */
+YY_LINENO_REWIND_TO(yy_cp - 1);
 (yy_c_buf_p) = yy_cp -= 1;
 YY_DO_BEFORE_ACTION; /* set up slice_text again */
 YY_RULE_SETUP
-#line 115 "Scanner.l"
+#line 117 "Scanner.l"
 {
     if(unit->scanPosition(slice_text))
     {
@@ -946,7 +966,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 5:
 YY_RULE_SETUP
-#line 122 "Scanner.l"
+#line 124 "Scanner.l"
 {
     // C++-style comment
     BEGIN(MAINSCAN);
@@ -964,7 +984,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 6:
 YY_RULE_SETUP
-#line 137 "Scanner.l"
+#line 139 "Scanner.l"
 {
     // C-style comment
     BEGIN(MAINSCAN);
@@ -1008,7 +1028,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 7:
 YY_RULE_SETUP
-#line 178 "Scanner.l"
+#line 180 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     return ICE_SCOPE_DELIMITER;
@@ -1016,7 +1036,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 8:
 YY_RULE_SETUP
-#line 183 "Scanner.l"
+#line 185 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     return ICE_METADATA_OPEN;
@@ -1024,7 +1044,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 9:
 YY_RULE_SETUP
-#line 188 "Scanner.l"
+#line 190 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     return ICE_METADATA_CLOSE;
@@ -1032,7 +1052,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 10:
 YY_RULE_SETUP
-#line 193 "Scanner.l"
+#line 195 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     return ICE_GLOBAL_METADATA_OPEN;
@@ -1040,7 +1060,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 11:
 YY_RULE_SETUP
-#line 198 "Scanner.l"
+#line 200 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     return ICE_GLOBAL_METADATA_CLOSE;
@@ -1049,7 +1069,7 @@ YY_RULE_SETUP
 case 12:
 /* rule 12 can match eol */
 YY_RULE_SETUP
-#line 203 "Scanner.l"
+#line 205 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     StringTokPtr ident = new StringTok;
@@ -1077,7 +1097,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 13:
 YY_RULE_SETUP
-#line 228 "Scanner.l"
+#line 230 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     StringTokPtr ident = new StringTok;
@@ -1088,163 +1108,279 @@ YY_RULE_SETUP
 	YY_BREAK
 case 14:
 YY_RULE_SETUP
-#line 236 "Scanner.l"
+#line 238 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     StringTokPtr str = new StringTok;
     str->literal = "\"";
     while(true)
     {
-	char c = static_cast<char>(yyinput());
+        char c = static_cast<char>(yyinput());
         str->literal += c;
-	if(c == '"')
-	{
-	    break;
-	}
-	else if(c == EOF)
-	{
-	    unit->error("EOF in string");
-	    break;
-	}
-	else if(c == '\n')
-	{
-	    unit->error("newline in string");
-	}
-	else if(c == '\\')
-	{
-	    char next = static_cast<char>(yyinput());
+        if(c == '"')
+        {
+            break;
+        }
+        else if(c == EOF)
+        {
+            unit->error("EOF in string");
+            break;
+        }
+        else if(c == '\n')
+        {
+            unit->error("newline in string");
+        }
+        else if(c == '\\')
+        {
+            char next = static_cast<char>(yyinput());
             str->literal += next;
-	    switch(next)
-	    {
-		case '\\':
-		case '"':
-		case '\'':
-		{
-		    str->v += next;
-		    break;
-		}
-	    
-		case 'n':
-		{
-		    str->v += '\n';
-		    break;
-		}
-	    
-		case 'r':
-		{
-		    str->v += '\r';
-		    break;
-		}
-
-		case 't':
-		{
-		    str->v += '\t';
-		    break;
-		}
-	    
-		case 'v':
-		{
-		    str->v += '\v';
-		    break;
-		}
-	    
-		case 'f':
-		{
-		    str->v += '\f';
-		    break;
-		}
-
-		case 'a':
-		{
-		    str->v += '\a';
-		    break;
-		}
-
-		case 'b':
-		{
-		    str->v += '\b';
-		    break;
-		}
-
-		case '?':
-		{
-		    str->v += '\?';
-		    break;
-		}
-
-		case '0':
-		case '1':
-		case '2':
-		case '3':
-		{
-		    static string octalDigits = "01234567";
-		    unsigned short us = next - '0';
-		    if(octalDigits.find_first_of(next = static_cast<char>(yyinput())) != string::npos)
-		    {
+            switch(next)
+            {
+                case '\\':
+                {
+                    str->v += '\\';
+                    str->v += '\\';
+                    break;
+                }
+                case '"':
+                case '\'':
+                {
+                    str->v += next;
+                    break;
+                }
+            
+                case 'n':
+                {
+                    str->v += '\n';
+                    break;
+                }
+            
+                case 'r':
+                {
+                    str->v += '\r';
+                    break;
+                }
+
+                case 't':
+                {
+                    str->v += '\t';
+                    break;
+                }
+            
+                case 'v':
+                {
+                    str->v += '\v';
+                    break;
+                }
+            
+                case 'f':
+                {
+                    str->v += '\f';
+                    break;
+                }
+
+                case 'a':
+                {
+                    str->v += '\a';
+                    break;
+                }
+
+                case 'b':
+                {
+                    str->v += '\b';
+                    break;
+                }
+
+                case '?':
+                {
+                    str->v += '\?';
+                    break;
+                }
+
+                //
+                // Octal value \nnn limited to three octal digits but terminate at the first character 
+                // that is not a valid octal digit if encountered sooner.
+                //
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '7':
+                {
+                    static string octalDigits = "01234567";
+                    IceUtil::Int64 value = 0;
+                    string escape;
+                    escape += next;
+                    for(int i = 0; i < 2; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
+                        if(octalDigits.find_first_of(next) == string::npos)
+                        {
+                            unput(next);
+                            break;
+                        }
+                        escape += next;                        
+                    }
+                    str->literal += escape;
+                    value = IceUtilInternal::strToInt64(escape.c_str(), 0, 8);
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    else if(value > 255)
+                    {
+                        ostringstream os;
+                        os << "octal escape sequence out of range: '\\" << oct << value << "'";
+                        unit->warning(os.str());
+                    }
+                    str->v += static_cast<char>(value);
+                    break;
+                }
+                case 'x':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+                    while(isxdigit(static_cast<unsigned char>(next = static_cast<char>(yyinput()))))
+                    {
+                        escape += next;
+                    }
+                    unput(next);
+                    
+                    str->literal += escape;
+                    value = IceUtilInternal::strToInt64(escape.c_str(), 0, 16);
+
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    else if(value > 255)
+                    {
+                        ostringstream os;
+                        os << "hex escape sequence out of range: '\\x" << hex << value << "'";
+                        unit->warning(os.str());
+                    }
+                    str->v += static_cast<char>(value);
+                    break;
+                }
+        
+                //
+                // Universal character name \unnnn code point U+nnnn
+                //
+                case 'u':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+
+                    for(int i = 0; i < 4; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
                         str->literal += next;
-		    	us = us * 8 + next - '0';
-			if(octalDigits.find_first_of(next = static_cast<char>(yyinput())) != string::npos)
-			{
-			    us = us * 8 + next - '0';
-			}
-			else
-			{
-			    unput(next);
-			}
-		    }
-		    else
-		    {
-		    	unput(next);
-		    }
-		    if(us == 0)
-		    {
-			unit->error("illegal NUL character in string constant");
-		    }
-		    str->v += static_cast<char>(us);
-		    break;
-		}
-		case 'x':
-		{
-		    IceUtil::Int64 ull = 0;
-		    while(isxdigit(static_cast<unsigned char>(next = static_cast<char>(yyinput()))))
-		    {
+                        if(!isxdigit(static_cast<unsigned char>(next)))
+                        {
+                            unit->error("unknown escape sequence in string constant: " + str->literal);
+                            break;
+                        }
+                        escape += next;
+                    }
+                    
+                    value = escape.size() == 4 ? IceUtilInternal::strToInt64(escape.c_str(), 0, 16) : -1;
+
+                    ostringstream os;
+                    os << '\\' << 'u';
+                    os.fill('0');
+                    os.width(4);
+                    os << hex << value;
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    
+                    
+                    //
+                    // Determine if a character is a surrogate:
+                    // 
+                    // * High surrogate code point, ranging from 0xd800 to 0xdbff, inclusive
+                    // * Low surrogate code point, ranging from 0xdc00 to 0xdfff, inclusive.
+                    //
+                    else if((value >= 0xd800 && value <= 0xdbff) || (value >= 0xdc00 && value <= 0xdfff))
+                    {
+                        unit->error("unknown escape sequence in string constant: '" + os.str() + "'");
+                    }
+
+                    str->v += os.str();
+                    
+                    break;
+                }
+                
+                case 'U':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+                    
+                    for(int i = 0; i < 8; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
                         str->literal += next;
-			ull *= 16;
-			if(isdigit(static_cast<unsigned char>(next)))
-			{
-			    ull += next - '0';
-			}
-			else if(islower(static_cast<unsigned char>(next)))
-			{
-			    ull += next - 'a' + 10;
-			}
-			else
-			{
-			    ull += next - 'A' + 10;
-			}
-		    }
-		    unput(next);
-		    if(ull == 0)
-		    {
-			unit->error("illegal NUL character in string constant");
-		    }
-		    str->v += static_cast<char>(ull);
-		    break;
-		}
-	
-		// TODO: add universal character names
-	    
-		default:
-		{
-		    str->v += c;
-		    unput(next);
-		}
-	    }
-	}
-	else
-	{
-	    str->v += c;
-	}
+                        if(!isxdigit(static_cast<unsigned char>(next)))
+                        {
+
+                            unit->error("unknown escape sequence in string constant: " + str->literal);
+                            break;
+                        }
+                        escape += next;
+                    }
+                    
+                    value = escape.size() == 8 ? IceUtilInternal::strToInt64(escape.c_str(), 0, 16) : -1;
+
+                    ostringstream os;
+                    os << '\\' << 'U';
+                    os.fill('0');
+                    os.width(8);
+                    os << hex << value;
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    
+                    //
+                    // Determine if a character is a surrogate:
+                    // 
+                    // * High surrogate code point, ranging from 0xd800 to 0xdbff, inclusive
+                    // * Low surrogate code point, ranging from 0xdc00 to 0xdfff, inclusive.
+                    //
+                    else if((value >= 0xd800 && value <= 0xdbff) || (value >= 0xdc00 && value <= 0xdfff))
+                    {
+                        unit->error("unknown escape sequence in string constant: '" + os.str() + "'");
+                    }
+
+                    str->v += os.str();
+                    break;
+                }
+
+                default:
+                {
+                    ostringstream os;
+                    os << "unknown escape sequence '\\" << next << "'";
+                    unit->warning(os.str());
+                    //
+                    // We escape the backslack in a unknown escape sequence 
+                    // to keep compativility with 3.6"
+                    //
+                    str->v += '\\';
+                    str->v += c;
+                    unput(next);
+                }
+            }
+        }
+        else
+        {
+            str->v += c;
+        }
     }
     *yylvalp = str;
     return ICE_STRING_LITERAL;
@@ -1252,7 +1388,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 15:
 YY_RULE_SETUP
-#line 397 "Scanner.l"
+#line 515 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     IntegerTokPtr itp = new IntegerTok;
@@ -1271,7 +1407,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 16:
 YY_RULE_SETUP
-#line 413 "Scanner.l"
+#line 531 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     errno = 0;
@@ -1305,7 +1441,7 @@ YY_RULE_SETUP
 case 17:
 /* rule 17 can match eol */
 YY_RULE_SETUP
-#line 443 "Scanner.l"
+#line 561 "Scanner.l"
 {
     // Ignore white-space
     
@@ -1321,7 +1457,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 18:
 YY_RULE_SETUP
-#line 456 "Scanner.l"
+#line 574 "Scanner.l"
 {
     // Ignore UTF-8 BOM, rule only active when parsing start of file.
     
@@ -1330,7 +1466,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 19:
 YY_RULE_SETUP
-#line 462 "Scanner.l"
+#line 580 "Scanner.l"
 {
     BEGIN(MAINSCAN);
     if(slice_text[0] < 32 || slice_text[0] > 126)
@@ -1349,10 +1485,10 @@ YY_RULE_SETUP
 	YY_BREAK
 case 20:
 YY_RULE_SETUP
-#line 478 "Scanner.l"
+#line 596 "Scanner.l"
 ECHO;
 	YY_BREAK
-#line 1355 "lex.yy.c"
+#line 1491 "lex.yy.c"
 case YY_STATE_EOF(INITIAL):
 case YY_STATE_EOF(BOMSCAN):
 case YY_STATE_EOF(MAINSCAN):
@@ -1486,6 +1622,7 @@ case YY_STATE_EOF(MAINSCAN):
 			"fatal flex scanner internal error--no action found" );
 	} /* end of action switch */
 		} /* end of scanning one token */
+	} /* end of user's declarations */
 } /* end of slice_lex */
 
 /* yy_get_next_buffer - try to read in a new buffer
@@ -1541,21 +1678,21 @@ static int yy_get_next_buffer (void)
 
 	else
 		{
-			int num_to_read =
+			yy_size_t num_to_read =
 			YY_CURRENT_BUFFER_LVALUE->yy_buf_size - number_to_move - 1;
 
 		while ( num_to_read <= 0 )
 			{ /* Not enough room in the buffer - grow it. */
 
 			/* just a shorter name for the current buffer */
-			YY_BUFFER_STATE b = YY_CURRENT_BUFFER;
+			YY_BUFFER_STATE b = YY_CURRENT_BUFFER_LVALUE;
 
 			int yy_c_buf_p_offset =
 				(int) ((yy_c_buf_p) - b->yy_ch_buf);
 
 			if ( b->yy_is_our_buffer )
 				{
-				int new_size = b->yy_buf_size * 2;
+				yy_size_t new_size = b->yy_buf_size * 2;
 
 				if ( new_size <= 0 )
 					b->yy_buf_size += b->yy_buf_size / 8;
@@ -1586,7 +1723,7 @@ static int yy_get_next_buffer (void)
 
 		/* Read in more data. */
 		YY_INPUT( (&YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[number_to_move]),
-			(yy_n_chars), (size_t) num_to_read );
+			(yy_n_chars), num_to_read );
 
 		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = (yy_n_chars);
 		}
@@ -1682,7 +1819,7 @@ static int yy_get_next_buffer (void)
 	yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c];
 	yy_is_jam = (yy_current_state == 72);
 
-	return yy_is_jam ? 0 : yy_current_state;
+		return yy_is_jam ? 0 : yy_current_state;
 }
 
     static void yyunput (int c, register char * yy_bp )
@@ -1697,7 +1834,7 @@ static int yy_get_next_buffer (void)
 	if ( yy_cp < YY_CURRENT_BUFFER_LVALUE->yy_ch_buf + 2 )
 		{ /* need to shift things up to make room */
 		/* +2 for EOB chars. */
-		register int number_to_move = (yy_n_chars) + 2;
+		register yy_size_t number_to_move = (yy_n_chars) + 2;
 		register char *dest = &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[
 					YY_CURRENT_BUFFER_LVALUE->yy_buf_size + 2];
 		register char *source =
@@ -1746,7 +1883,7 @@ static int yy_get_next_buffer (void)
 
 		else
 			{ /* need more input */
-			int offset = (yy_c_buf_p) - (yytext_ptr);
+			yy_size_t offset = (yy_c_buf_p) - (yytext_ptr);
 			++(yy_c_buf_p);
 
 			switch ( yy_get_next_buffer(  ) )
@@ -2020,7 +2157,7 @@ void slice_pop_buffer_state (void)
  */
 static void slice_ensure_buffer_stack (void)
 {
-	int num_to_alloc;
+	yy_size_t num_to_alloc;
     
 	if (!(yy_buffer_stack)) {
 
@@ -2112,17 +2249,17 @@ YY_BUFFER_STATE slice__scan_string (yyconst char * yystr )
 
 /** Setup the input buffer state to scan the given bytes. The next call to slice_lex() will
  * scan from a @e copy of @a bytes.
- * @param bytes the byte buffer to scan
- * @param len the number of bytes in the buffer pointed to by @a bytes.
+ * @param yybytes the byte buffer to scan
+ * @param _yybytes_len the number of bytes in the buffer pointed to by @a bytes.
  * 
  * @return the newly allocated buffer state object.
  */
-YY_BUFFER_STATE slice__scan_bytes  (yyconst char * yybytes, int  _yybytes_len )
+YY_BUFFER_STATE slice__scan_bytes  (yyconst char * yybytes, yy_size_t  _yybytes_len )
 {
 	YY_BUFFER_STATE b;
 	char *buf;
 	yy_size_t n;
-	int i;
+	yy_size_t i;
     
 	/* Get memory for full buffer, including space for trailing EOB's. */
 	n = _yybytes_len + 2;
@@ -2204,7 +2341,7 @@ FILE *slice_get_out  (void)
 /** Get the length of the current token.
  * 
  */
-int slice_get_leng  (void)
+yy_size_t slice_get_leng  (void)
 {
         return slice_leng;
 }
@@ -2352,7 +2489,7 @@ void slice_free (void * ptr )
 
 #define YYTABLES_NAME "yytables"
 
-#line 478 "Scanner.l"
+#line 595 "Scanner.l"
 
 
 
diff --git a/cpp/src/Slice/Scanner.l b/cpp/src/Slice/Scanner.l
index a5f8d439a2d..9054c1e90ed 100644
--- a/cpp/src/Slice/Scanner.l
+++ b/cpp/src/Slice/Scanner.l
@@ -13,6 +13,8 @@
 #include <Slice/Grammar.h>
 #include <IceUtil/InputUtil.h>
 
+#include <iomanip>
+
 #include <stdlib.h>
 #include <math.h>
 
@@ -239,156 +241,272 @@ floating_literal	(({fractional_constant}{exponent_part}?)|((\+|-)?[[:digit:]]+{e
     str->literal = "\"";
     while(true)
     {
-	char c = static_cast<char>(yyinput());
+        char c = static_cast<char>(yyinput());
         str->literal += c;
-	if(c == '"')
-	{
-	    break;
-	}
-	else if(c == EOF)
-	{
-	    unit->error("EOF in string");
-	    break;
-	}
-	else if(c == '\n')
-	{
-	    unit->error("newline in string");
-	}
-	else if(c == '\\')
-	{
-	    char next = static_cast<char>(yyinput());
+        if(c == '"')
+        {
+            break;
+        }
+        else if(c == EOF)
+        {
+            unit->error("EOF in string");
+            break;
+        }
+        else if(c == '\n')
+        {
+            unit->error("newline in string");
+        }
+        else if(c == '\\')
+        {
+            char next = static_cast<char>(yyinput());
             str->literal += next;
-	    switch(next)
-	    {
-		case '\\':
-		case '"':
-		case '\'':
-		{
-		    str->v += next;
-		    break;
-		}
-	    
-		case 'n':
-		{
-		    str->v += '\n';
-		    break;
-		}
-	    
-		case 'r':
-		{
-		    str->v += '\r';
-		    break;
-		}
-
-		case 't':
-		{
-		    str->v += '\t';
-		    break;
-		}
-	    
-		case 'v':
-		{
-		    str->v += '\v';
-		    break;
-		}
-	    
-		case 'f':
-		{
-		    str->v += '\f';
-		    break;
-		}
-
-		case 'a':
-		{
-		    str->v += '\a';
-		    break;
-		}
-
-		case 'b':
-		{
-		    str->v += '\b';
-		    break;
-		}
-
-		case '?':
-		{
-		    str->v += '\?';
-		    break;
-		}
-
-		case '0':
-		case '1':
-		case '2':
-		case '3':
-		{
-		    static string octalDigits = "01234567";
-		    unsigned short us = next - '0';
-		    if(octalDigits.find_first_of(next = static_cast<char>(yyinput())) != string::npos)
-		    {
+            switch(next)
+            {
+                case '\\':
+                {
+                    str->v += '\\';
+                    str->v += '\\';
+                    break;
+                }
+                case '"':
+                case '\'':
+                {
+                    str->v += next;
+                    break;
+                }
+            
+                case 'n':
+                {
+                    str->v += '\n';
+                    break;
+                }
+            
+                case 'r':
+                {
+                    str->v += '\r';
+                    break;
+                }
+
+                case 't':
+                {
+                    str->v += '\t';
+                    break;
+                }
+            
+                case 'v':
+                {
+                    str->v += '\v';
+                    break;
+                }
+            
+                case 'f':
+                {
+                    str->v += '\f';
+                    break;
+                }
+
+                case 'a':
+                {
+                    str->v += '\a';
+                    break;
+                }
+
+                case 'b':
+                {
+                    str->v += '\b';
+                    break;
+                }
+
+                case '?':
+                {
+                    str->v += '\?';
+                    break;
+                }
+
+                //
+                // Octal value \nnn limited to three octal digits but terminate at the first character 
+                // that is not a valid octal digit if encountered sooner.
+                //
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '7':
+                {
+                    static string octalDigits = "01234567";
+                    IceUtil::Int64 value = 0;
+                    string escape;
+                    escape += next;
+                    for(int i = 0; i < 2; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
+                        if(octalDigits.find_first_of(next) == string::npos)
+                        {
+                            unput(next);
+                            break;
+                        }
+                        escape += next;                        
+                    }
+                    str->literal += escape;
+                    value = IceUtilInternal::strToInt64(escape.c_str(), 0, 8);
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    else if(value > 255)
+                    {
+                        ostringstream os;
+                        os << "octal escape sequence out of range: '\\" << oct << value << "'";
+                        unit->warning(os.str());
+                    }
+                    str->v += static_cast<char>(value);
+                    break;
+                }
+                case 'x':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+                    while(isxdigit(static_cast<unsigned char>(next = static_cast<char>(yyinput()))))
+                    {
+                        escape += next;
+                    }
+                    unput(next);
+                    
+                    str->literal += escape;
+                    value = IceUtilInternal::strToInt64(escape.c_str(), 0, 16);
+
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    else if(value > 255)
+                    {
+                        ostringstream os;
+                        os << "hex escape sequence out of range: '\\x" << hex << value << "'";
+                        unit->warning(os.str());
+                    }
+                    str->v += static_cast<char>(value);
+                    break;
+                }
+        
+                //
+                // Universal character name \unnnn code point U+nnnn
+                //
+                case 'u':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+
+                    for(int i = 0; i < 4; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
                         str->literal += next;
-		    	us = us * 8 + next - '0';
-			if(octalDigits.find_first_of(next = static_cast<char>(yyinput())) != string::npos)
-			{
-			    us = us * 8 + next - '0';
-			}
-			else
-			{
-			    unput(next);
-			}
-		    }
-		    else
-		    {
-		    	unput(next);
-		    }
-		    if(us == 0)
-		    {
-			unit->error("illegal NUL character in string constant");
-		    }
-		    str->v += static_cast<char>(us);
-		    break;
-		}
-		case 'x':
-		{
-		    IceUtil::Int64 ull = 0;
-		    while(isxdigit(static_cast<unsigned char>(next = static_cast<char>(yyinput()))))
-		    {
+                        if(!isxdigit(static_cast<unsigned char>(next)))
+                        {
+                            unit->error("unknown escape sequence in string constant: " + str->literal);
+                            break;
+                        }
+                        escape += next;
+                    }
+                    
+                    value = escape.size() == 4 ? IceUtilInternal::strToInt64(escape.c_str(), 0, 16) : -1;
+
+                    ostringstream os;
+                    os << '\\' << 'u';
+                    os.fill('0');
+                    os.width(4);
+                    os << hex << value;
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    
+                    
+                    //
+                    // Determine if a character is a surrogate:
+                    // 
+                    // * High surrogate code point, ranging from 0xd800 to 0xdbff, inclusive
+                    // * Low surrogate code point, ranging from 0xdc00 to 0xdfff, inclusive.
+                    //
+                    else if((value >= 0xd800 && value <= 0xdbff) || (value >= 0xdc00 && value <= 0xdfff))
+                    {
+                        unit->error("unknown escape sequence in string constant: '" + os.str() + "'");
+                    }
+
+                    str->v += os.str();
+                    
+                    break;
+                }
+                
+                case 'U':
+                {
+                    IceUtil::Int64 value = 0;
+                    string escape = "";
+                    
+                    for(int i = 0; i < 8; ++i)
+                    {
+                        next = static_cast<char>(yyinput());
                         str->literal += next;
-			ull *= 16;
-			if(isdigit(static_cast<unsigned char>(next)))
-			{
-			    ull += next - '0';
-			}
-			else if(islower(static_cast<unsigned char>(next)))
-			{
-			    ull += next - 'a' + 10;
-			}
-			else
-			{
-			    ull += next - 'A' + 10;
-			}
-		    }
-		    unput(next);
-		    if(ull == 0)
-		    {
-			unit->error("illegal NUL character in string constant");
-		    }
-		    str->v += static_cast<char>(ull);
-		    break;
-		}
-	
-		// TODO: add universal character names
-	    
-		default:
-		{
-		    str->v += c;
-		    unput(next);
-		}
-	    }
-	}
-	else
-	{
-	    str->v += c;
-	}
+                        if(!isxdigit(static_cast<unsigned char>(next)))
+                        {
+
+                            unit->error("unknown escape sequence in string constant: " + str->literal);
+                            break;
+                        }
+                        escape += next;
+                    }
+                    
+                    value = escape.size() == 8 ? IceUtilInternal::strToInt64(escape.c_str(), 0, 16) : -1;
+
+                    ostringstream os;
+                    os << '\\' << 'U';
+                    os.fill('0');
+                    os.width(8);
+                    os << hex << value;
+                    
+                    if(value == 0)
+                    {
+                        unit->error("illegal NUL character in string constant");
+                    }
+                    
+                    //
+                    // Determine if a character is a surrogate:
+                    // 
+                    // * High surrogate code point, ranging from 0xd800 to 0xdbff, inclusive
+                    // * Low surrogate code point, ranging from 0xdc00 to 0xdfff, inclusive.
+                    //
+                    else if((value >= 0xd800 && value <= 0xdbff) || (value >= 0xdc00 && value <= 0xdfff))
+                    {
+                        unit->error("unknown escape sequence in string constant: '" + os.str() + "'");
+                    }
+
+                    str->v += os.str();
+                    break;
+                }
+
+                default:
+                {
+                    ostringstream os;
+                    os << "unknown escape sequence '\\" << next << "'";
+                    unit->warning(os.str());
+                    //
+                    // We escape the backslack in a unknown escape sequence 
+                    // to keep compativility with 3.6"
+                    //
+                    str->v += '\\';
+                    str->v += c;
+                    unput(next);
+                }
+            }
+        }
+        else
+        {
+            str->v += c;
+        }
     }
     *yylvalp = str;
     return ICE_STRING_LITERAL;