diff options
Diffstat (limited to 'mbf.cpp')
| -rw-r--r-- | mbf.cpp | 158 |
1 files changed, 158 insertions, 0 deletions
@@ -0,0 +1,158 @@ +// mbf.cpp +// Revision 9-jul-2004 + +#include "mbf.h" +#include "error.h" + +#include <math.h> + +// For debugging: +#include <iostream> +#include <iomanip> + +double mbf::mbf_s (const std::string & s) +{ + if (s.size () != 4) + throw ErrFunctionCall; + unsigned char b0= s [0], b1= s [1], b2= s [2], b3= s [3]; + double n= (b2 & 0x7F) | 0x80; + n= 256 * n + b1; + n= 256 * n + b0; + short e= static_cast <short> (b3 - 128 - 24); + if (e > 0) + for ( ; e > 0; --e) + n*= 2; + else + for ( ; e < 0; ++e) + n/= 2; + if (b2 & 0x80) + n= -n; + return n; +} + +double mbf::mbf_d (const std::string & s) +{ + if (s.size () != 8) + throw ErrFunctionCall; + unsigned char b0= s [0], b1= s [1], b2= s [2], b3= s [3], + b4= s [4], b5= s [5], b6= s [6], b7= s [7]; + double n= (b6 & 0x7F) | 0x80; + n= 256 * n + b5; + n= 256 * n + b4; + n= 256 * n + b3; + n= 256 * n + b2; + n= 256 * n + b1; + n= 256 * n + b0; + short e= static_cast <short> (b7 - 128 - 56); + if (e > 0) + for ( ; e > 0; --e) + n*= 2; + else + for ( ; e < 0; ++e) + n/= 2; + if (b6 & 0x80) + n= -n; + return n; +} + +namespace { + +double zero= 0.0; + +} // namespace + +std::string mbf::to_mbf_s (double v) +{ + bool negative= v < 0; + if (negative) + v= -v; + int e= static_cast <int> (log (v) / log (2) ); + v/= pow (2, e - 23); + unsigned long l= static_cast <unsigned long> (v); + + #if 0 + std::cerr << "e= " << std::dec << e << + " l= " << std::hex << + std::setw (8) << std::setfill ('0') << + l << std::endl; + #endif + + unsigned char b3= static_cast <unsigned char> (e + 128 + 1); + unsigned char b2= static_cast <unsigned char> (l / (256 * 256) ); + unsigned char b1= static_cast <unsigned char> ((l / 256) % 256); + unsigned char b0= static_cast <unsigned char> (l % 256); + b2&= 0x7F; + if (negative) + b2|= 0x80; + #if 0 + std::cerr << std::setw (2) << int (b0) << int (b1) << + int (b2) << int (b3) << std::endl; + #endif + + return std::string (1, char (b0) ) + char (b1) + char (b2) + char (b3); +} + +std::string mbf::to_mbf_d (double v) +{ + bool negative= v < 0; + if (negative) + v= -v; + int e= static_cast <int> (log (v) / log (2) ); + v/= pow (2, e - 55); + //unsigned long l= static_cast <unsigned long> (v); + double l; + modf (v, & l); + + #if 0 + std::cerr << "e= " << std::dec << e << + " l= " << std::hex << + std::setw (8) << std::setfill ('0') << + l << std::endl; + #endif + + unsigned char b7= static_cast <unsigned char> (e + 128 + 1); + + #if 0 + unsigned char b6= l / (256.0 * 256 * 256 * 256 * 256 * 256); + unsigned char b5= (l / (256.0 * 256 * 256 * 256 * 256) ) % 256.0; + unsigned char b4= (l / (256.0 * 256 * 256 * 256) ) % 256.0; + unsigned char b3= (l / (256UL * 256 * 256) ) % 256.0; + unsigned char b2= (l / (256 * 256) ) % 256.0; + unsigned char b1= (l / 256) % 256.0; + unsigned char b0= l % 256.0; + #else + double ll; + modf (l / 256, & ll); + unsigned char b0= static_cast <unsigned char> (l - 256 * ll); + l= ll; + modf (l / 256, & ll); + unsigned char b1= static_cast <unsigned char> (l - 256 * ll); + l= ll; + modf (l / 256, & ll); + unsigned char b2= static_cast <unsigned char> (l - 256 * ll); + l= ll; + modf (l / 256, & ll); + unsigned char b3= static_cast <unsigned char> (l - 256 * ll); + l= ll; + modf (l / 256, & ll); + unsigned char b4= static_cast <unsigned char> (l - 256 * ll); + l= ll; + modf (l / 256, & ll); + unsigned char b5= static_cast <unsigned char> (l - 256 * ll); + l= ll; + unsigned char b6= static_cast <unsigned char> (l); + #endif + b6&= 0x7F; + if (negative) + b6|= 0x80; + + #if 0 + std::cerr << std::setw (2) << int (b0) << int (b1) << + int (b2) << int (b3) << std::endl; + #endif + + return std::string (1, char (b0) ) + char (b1) + char (b2) + + char (b3) + char (b4) + char (b5) + char (b6) + char (b7); +} + +// End of mbf.cpp |