UtfString is going really well. It can now parse Utf8, Utf16 (le,be), and

Utf32 (le,be).  The internal storage seems to be working fine, although we do
have a problem with random access, but at least we can tell which half of a
surrogate pair we're on, so we can always rapidly determine the entire code
point from any utf16 index that we're on.
The only optomization that I'm not doing yet is reading in entire 16bit or 32bit
words at a time and converting them from their byte order to native.  There are
a few potential issues with that, so we'll see.

I added a couple of testing datafiles and a test program, I'll delete them all
just as soon as it's verified to write correctly.

6 files changed, 319 insertions, 18 deletions

diff --git a/src/utfstring.cpp b/src/utfstring.cpp
index bb0a011..7c4ba19 100644
--- a/src/utfstring.cpp
+++ b/src/utfstring.cpp
@@ -8,9 +8,13 @@
 #include "bu/utfstring.h"
 
 #include "bu/string.h"
+#include "bu/stream.h"
 
 #include <endian.h>
 
+#include "bu/sio.h"
+using Bu::sio;
+
 Bu::UtfString::UtfString()
 {
 }
@@ -33,20 +37,35 @@ void Bu::UtfString::set( const Bu::String &sInput, Encoding eEnc )
                         break;
 
                 case Utf16:
-                case Utf16be:
                         setUtf16( sInput );
                         break;
 
+                case Utf16be:
+                        setUtf16be( sInput );
+                        break;
+
                 case Utf16le:
-                        throw Bu::ExceptionBase("Utf16le not supported yet.");
+                        setUtf16le( sInput );
                         break;
 
                 case Utf32:
-                        throw Bu::ExceptionBase("Utf32 not supported yet.");
+                        setUtf32( sInput );
+                        break;
+
+                case Utf32be:
+                        setUtf32be( sInput );
+                        break;
+
+                case Utf32le:
+                        setUtf32le( sInput );
+                        break;
+
+                case Ucs2:
+                        throw Bu::ExceptionBase("Ucs2 not supported yet.");
                         break;
 
-                case Ucs16:
-                        throw Bu::ExceptionBase("Ucs16 not supported yet.");
+                case Ucs4:
+                        throw Bu::ExceptionBase("Ucs4 not supported yet.");
                         break;
 
                 case GuessEncoding:
@@ -104,8 +123,32 @@ void Bu::UtfString::setUtf8( const Bu::String &sInput )
 
 void Bu::UtfString::setUtf16( const Bu::String &sInput )
 {
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*sInput.begin() == 0xFF &&
+                (uint8_t)*(sInput.begin()+1) == 0xFE )
+        {
+                setUtf16le( sInput );
+                return;
+        }
+        setUtf16be( sInput );
+}
+
+void Bu::UtfString::setUtf16be( const Bu::String &sInput )
+{
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*sInput.begin() == 0xFE &&
+                (uint8_t)*(sInput.begin()+1) == 0xFF )
+
+        {
+                i += 2;
+                sio << "Verified big endian." << sio.nl;
+        }
+        else
+        {
+                sio << "Assuming big endian." << sio.nl;
+        }
         uint16_t hi, lo;
-        for( Bu::String::const_iterator i = sInput.begin(); i; i++ )
+        for( ; i; i++ )
         {
                 hi = (((uint8_t)*i)<<8) | ((uint8_t)*(++i));
                 append16( hi );
@@ -117,25 +160,192 @@ void Bu::UtfString::setUtf16( const Bu::String &sInput )
         }
 }
 
-#include "bu/sio.h"
-using Bu::sio;
+void Bu::UtfString::setUtf16le( const Bu::String &sInput )
+{
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*sInput.begin() == 0xFF &&
+                (uint8_t)*(sInput.begin()+1) == 0xFE )
+        {
+                i += 2;
+                sio << "Verified little endian." << sio.nl;
+        }
+        else
+        {
+                sio << "Assuming little endian." << sio.nl;
+        }
+        uint16_t hi, lo;
+        for( ; i; i++ )
+        {
+                hi = (((uint8_t)*i)) | ((uint8_t)*(++i)<<8);
+                append16( hi );
+                if( (hi&0xD800u) == 0xD800u )
+                {
+                        lo = (((uint8_t)*(++i))) | ((uint8_t)*(++i)<<8);
+                        append16( lo );
+                }
+        }
+}
+
+void Bu::UtfString::setUtf32( const Bu::String &sInput )
+{
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*i == 0x00 &&
+                (uint8_t)*(++i) == 0x00 &&
+                (uint8_t)*(++i) == 0xFF &&
+                (uint8_t)*(++i) == 0xFE )
+        {
+                setUtf32le( sInput );
+                return;
+        }
+        setUtf32be( sInput );
+}
+
+void Bu::UtfString::setUtf32be( const Bu::String &sInput )
+{
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*i == 0x00 &&
+                (uint8_t)*(++i) == 0x00 &&
+                (uint8_t)*(++i) == 0xFE &&
+                (uint8_t)*(++i) == 0xFF )
+        {
+                i++;
+                sio << "Verified big endian." << sio.nl;
+        }
+        else
+        {
+                i = sInput.begin();
+                sio << "Assuming big endian." << sio.nl;
+        }
+        for( ; i; i++ )
+        {
+                append( (((uint8_t)*i)<<24) |
+                                (((uint8_t)*(++i))<<16) |
+                                (((uint8_t)*(++i))<<8) |
+                                ((uint8_t)*(++i))
+                          );
+        }
+}
+
+void Bu::UtfString::setUtf32le( const Bu::String &sInput )
+{
+        Bu::String::const_iterator i = sInput.begin();
+        if( (uint8_t)*i == 0x00 &&
+                (uint8_t)*(++i) == 0x00 &&
+                (uint8_t)*(++i) == 0xFF &&
+                (uint8_t)*(++i) == 0xFE )
+        {
+                i++;
+                sio << "Verified little endian." << sio.nl;
+        }
+        else
+        {
+                i = sInput.begin();
+                sio << "Assuming little endian." << sio.nl;
+        }
+        for( ; i; i++ )
+        {
+                append( ((uint8_t)*i) |
+                                (((uint8_t)*(++i))<<8) |
+                                (((uint8_t)*(++i))<<16) |
+                                (((uint8_t)*(++i))<<24)
+                          );
+        }
+}
+
+void Bu::UtfString::write( Bu::Stream &sOut, Encoding eEnc )
+{
+        switch( eEnc )
+        {
+                case Utf8:
+                        writeUtf8( sOut );
+                        break;
+
+                case Utf16:
+                        writeUtf16( sOut );
+                        break;
+
+                case Utf16be:
+                        writeUtf16be( sOut );
+                        break;
+
+                case Utf16le:
+                        writeUtf16le( sOut );
+                        break;
+
+                case Utf32:
+                        writeUtf32( sOut );
+                        break;
+
+                case Utf32be:
+                        writeUtf32be( sOut );
+                        break;
+
+                case Utf32le:
+                        writeUtf32le( sOut );
+                        break;
+
+                case Ucs2:
+                        throw Bu::ExceptionBase("Ucs2 not supported yet.");
+                        break;
+
+                case Ucs4:
+                        throw Bu::ExceptionBase("Ucs4 not supported yet.");
+                        break;
+
+                case GuessEncoding:
+                        throw Bu::ExceptionBase(
+                                "GuessEncoding is incompatible with encoding.");
+                        break;
+
+        }
+}
+
+void Bu::UtfString::writeUtf8( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf16( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf16be( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf16le( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf32( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf32be( Bu::Stream &sOut )
+{
+}
+
+void Bu::UtfString::writeUtf32le( Bu::Stream &sOut )
+{
+}
 
 Bu::UtfChar Bu::UtfString::get( int iIndex )
 {
-        Bu::UtfChar i = aData[iIndex];
+        return nextChar( iIndex );
+}
+
+Bu::UtfChar Bu::UtfString::nextChar( int &iIndex )
+{
+        Bu::UtfChar i = aData[iIndex++];
         switch( i&0xFC00 )
         {
                 case 0xD800:
-                        sio << "(hi) ";
-                        return (((i&0x3FF)<<10) | ((aData[iIndex+1]&0x3FF)))+0x10000;
+                        return (((i&0x3FF)<<10) | ((aData[iIndex++]&0x3FF)))+0x10000;
 
                 case 0xDC00:
-                        sio << "(lo) ";
-                        return 0;
+                        return (((aData[iIndex-2]&0x3FF)<<10) | ((i&0x3FF)))+0x10000;
 
                 default:
-                        sio << "(--) ";
-                        return i&0xFC00;
+                        return i;
         }
 }
 
diff --git a/src/utfstring.h b/src/utfstring.h
index 79ef62e..8448ea4 100644
--- a/src/utfstring.h
+++ b/src/utfstring.h
@@ -14,6 +14,7 @@
 namespace Bu
 {
         class String;
+        class Stream;
 
         /**
          * UtfChar isn't actually a character, unicode specifies "code points" not
@@ -35,7 +36,10 @@ namespace Bu
                         Utf16be,
                         Utf16le,
                         Utf32,
-                        Ucs16,
+                        Utf32be,
+                        Utf32le,
+                        Ucs2,
+                        Ucs4,
                         GuessEncoding
                 };
 
@@ -43,17 +47,59 @@ namespace Bu
                 UtfString( const Bu::String &sInput, Encoding eEnc=Utf8 );
                 virtual ~UtfString();
 
+                class iterator
+                {
+                private:
+                        iterator( UtfString *pSrc, int iCodePos ) :
+                                pSrc( pSrc ), iCodePos( iCodePos )
+                        {
+                        }
+
+                public:
+                        iterator() :
+                                pSrc( NULL ), iCodePos( 0 )
+                        {
+                        }
+
+                        UtfChar operator*()
+                        {
+                                if( !pSrc )
+                                        throw Bu::ExceptionBase("invalid UtfString::iterator dereferenced.");
+                                return pSrc->nextChar( iCodePos );
+                        }
+
+                private:
+                        UtfString *pSrc;
+                        int iCodePos;
+                };
+
                 void append( UtfChar ch );
 
                 void set( const Bu::String &sInput, Encoding eEnc=Utf8 );
                 void setUtf8( const Bu::String &sInput );
                 void setUtf16( const Bu::String &sInput );
-//              void setUtf16be( const Bu::String &sInput );
-//              void setUtf16le( const Bu::String &sInput );
+                void setUtf16be( const Bu::String &sInput );
+                void setUtf16le( const Bu::String &sInput );
+                void setUtf32( const Bu::String &sInput );
+                void setUtf32be( const Bu::String &sInput );
+                void setUtf32le( const Bu::String &sInput );
+
+                void write( Bu::Stream &sOut, Encoding eEnc=Utf8 );
+                void writeUtf8( Bu::Stream &sOut );
+                void writeUtf16( Bu::Stream &sOut );
+                void writeUtf16be( Bu::Stream &sOut );
+                void writeUtf16le( Bu::Stream &sOut );
+                void writeUtf32( Bu::Stream &sOut );
+                void writeUtf32be( Bu::Stream &sOut );
+                void writeUtf32le( Bu::Stream &sOut );
+
+                Bu::String to( Encoding eEnc=Utf8 );
+                Bu::String toUtf8();
 
                 void debug();
 
                 UtfChar get( int iIndex );
+                UtfChar nextChar( int &iIndex );
 
         private:
                 void append16( uint16_t i ) { aData.append( i ); }
diff --git a/test.utf16 b/test.utf16
new file mode 100644
index 0000000..86a63c3
--- /dev/null
+++ b/test.utf16
@@ -0,0 +1 @@
+¥Ëæ)˜Ø=Þ<Ûÿßý$H
\ No newline at end of file
diff --git a/test.utf16be b/test.utf16be
new file mode 100644
index 0000000..136ad1a
--- /dev/null
+++ b/test.utf16be
@@ -0,0 +1 @@
+þÿ¥Ëæ)˜Ø=Þ<Ûÿßý$H
\ No newline at end of file
diff --git a/test.utf16le b/test.utf16le
new file mode 100644
index 0000000..9f610d6
--- /dev/null
+++ b/test.utf16le
@@ -0,0 +1 @@
+ÿþ¥Ëæ˜)=Ø<ÞÿÛýßH$
\ No newline at end of file
diff --git a/utf16.cpp b/utf16.cpp
new file mode 100644
index 0000000..eedb521
--- /dev/null
+++ b/utf16.cpp
@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdint.h>
+
+void bitprint( uint16_t u )
+{
+        for( int i = 15; i >= 0; i-- )
+                printf("%c", (u&(1<<i))?'1':'0');
+        printf("\n");
+}
+
+void bitprint( uint32_t u )
+{
+        for( int i = 31; i >= 0; i-- )
+                printf("%c", (u&(1<<i))?'1':'0');
+        printf("\n");
+}
+
+void utoutf16( uint32_t in, uint16_t &outHi, uint16_t &outLo )
+{
+        outHi = (((in-0x10000)>>10)&0x3FF)| 0xD800u;
+        outLo = ((in-0x10000)&0x3FF)| 0xDC00u;
+        printf("0x%X == 0x%X, 0x%X\n", in, outHi, outLo );
+}
+
+int32_t utf16tou( uint16_t hi, uint16_t lo )
+{
+        return (((uint32_t)hi&0x3FF)<<10 | lo&0x3FF)+0x10000;
+}
+
+int main()
+{
+        bitprint( 0xD800u );
+        bitprint( 0xDC00u );
+        uint16_t hi, lo;
+        utoutf16( 0x1D11E, hi, lo ); // Cat face with wry smile
+        utoutf16( 0x10FFFD, hi, lo ); // Cat face with wry smile
+        utoutf16( 0x1F63C, hi, lo ); // Cat face with wry smile
+        bitprint( hi );
+        bitprint( lo );
+        printf("0x%X\n", utf16tou( hi, lo ) );
+        return 0;
+}