1 files changed, 130 insertions, 0 deletions

diff --git a/src/tools/float.cpp b/src/tools/float.cpp
new file mode 100644
index 0000000..2c241f3
--- /dev/null
+++ b/src/tools/float.cpp
@@ -0,0 +1,130 @@
+#include <bu/sio.h>
+#include <bu/string.h>
+#include <stdlib.h>
+#include <math.h>
+
+using namespace Bu;
+
+Bu::String ftos( double dNum )
+{
+        if( dNum == 1.0 )
+                return "0x1p+0";
+        if( dNum == 0.0 )
+                return signbit(dNum)?"-0x0p+0":"0x0p+0";
+        if( dNum == -1.0 )
+                return "-0x1p+0";
+        Bu::String s("0x1.");
+        if( signbit(dNum) )
+        {
+                s.prepend("-");
+                dNum = -dNum;
+        }
+/*      
+        for( int j = 0; j < 150 && dNum; j++ )
+        {
+                dNum = dNum*2;
+                sio << dNum << " -- " << (int)dNum << sio.nl;
+                if( (int)dNum == 0 )
+                        s += '0';
+                else
+                {
+                        s += '1';
+                        dNum -= 1.0;
+                }
+        }
+        return s;
+        */
+        int iPower = 0;
+        if( dNum < 1.0 )
+        {
+                while( dNum < 1.0 )
+                {
+                        dNum *= 2.0;
+                        iPower--;
+                }
+        }
+        else if( dNum >= 2.0 )
+        {
+                while( dNum >= 2.0 )
+                {
+                        dNum *= 0.5;
+                        iPower++;
+                }
+        }
+        dNum -= (int)dNum;
+        for( int j = 0; j < 150 && dNum; j++ )
+        {
+                dNum = dNum*16.0;
+                s += "0123456789abcdef"[(int)dNum];
+                dNum -= (int)dNum;
+        }
+        s.formatAppend("p%+d", iPower );
+        return s;
+}
+
+double stof( const Bu::String &s )
+{
+        if( s == "0x1p+0" )
+                return 1.0;
+        if( s == "-0x1p+0" )
+                return -1.0;
+        if( s == "0x0p+0" )
+                return 0.0;
+        if( s == "-0x0p+0" )
+                return 0.0;
+        double dNum = 0.0;
+        int iPPos = s.getSize()-1;
+        for(; s[iPPos] != 'p'; iPPos--) { }
+        for( int i = iPPos-1; s[i] != '.'; i-- )
+        {
+                if( s[i]>='0' && s[i]<='9' )
+                {
+                        dNum += s[i]-'0';
+                }
+                else if( s[i]>='a' && s[i]<='f' )
+                {
+                        dNum += s[i]-'a'+10.0;
+                }
+                dNum *= 0.0625;
+        }
+
+        dNum += 1.0;
+
+        int iTop = strtol( s.getStr()+iPPos+1, NULL, 10 );
+        if( iTop < 0 )
+        {
+                for( int j = 0; j > iTop; j-- )
+                {
+                        dNum *= 0.5;
+                }
+        }
+        else
+        {
+                for( int j = 0; j < iTop; j++ )
+                {
+                        dNum *= 2.0;
+                }
+        }
+
+        if( s[0] == '-' )
+                return -dNum;
+        return dNum;
+}
+
+int main( int argc, char *argv[] )
+{
+        for( int j = 1; j < argc; j++ )
+        {
+                double dNum = strtod( argv[j], NULL );
+
+                String s = ftos( dNum );
+                sio << "in:     " << dNum << sio.nl;
+                sio << "mine:   " << s << sio.nl;
+                printf("printf: %a\n", dNum );
+                sio << "out:    " << stof( s ) << sio.nl;
+                sio << "match:  " << (stof( s ) == dNum) << sio.nl << sio.nl;
+        }
+
+        return 0;
+}
+