/* A test program to which explores the ability to round trip a nanometer internal unit in the form of a 32 bit int, out to ASCII floating point millimeters and back in without variation. It tests all 4 billion values that an int can hold, and converts to ASCII and back and verifies integrity of the round tripped value. Author: Dick Hollenbeck */ #include <limits.h> #include <stdio.h> #include <cmath> #include <string> #include <string.h> #include <stdlib.h> #include <stdint.h> static inline int KiROUND( double v ) { return int( v < 0 ? v - 0.5 : v + 0.5 ); } typedef int BIU; #define BIU_PER_MM 1e6 //double scale = BIU_PER_MM; //double scale = UM_PER_BIU; double scale = 1.0/BIU_PER_MM; std::string biuFmt( BIU aValue ) { double engUnits = aValue * scale; char temp[48]; int len; if( engUnits != 0.0 && fabsl( engUnits ) <= 0.0001 ) { len = snprintf( temp, sizeof( temp ), "%.10f", engUnits ); while( --len > 0 && temp[len] == '0' ) temp[len] = '\0'; ++len; } else { len = snprintf( temp, sizeof( temp ), "%.10g", engUnits ); } return std::string( temp, len );; } int parseBIU( const char* s ) { double d = strtod( s, NULL ); return KiROUND( double( d * BIU_PER_MM ) ); // return int( d * BIU_PER_MM ); } int main( int argc, char** argv ) { unsigned mismatches = 0; if( argc > 1 ) { // take a value on the command line and round trip it back to ASCII. int i = parseBIU( argv[1] ); printf( "%s: i:%d\n", __func__, i ); std::string s = biuFmt( i ); printf( "%s: s:%s\n", __func__, s.c_str() ); exit(0); } // printf( "sizeof(long double): %zd\n", sizeof( long double ) ); // Emperically prove that we can round trip all 4 billion 32 bit integers representative // of nanometers out to textual floating point millimeters, and back without error using // the above two functions. // for( int i = INT_MIN; int64_t( i ) <= int64_t( INT_MAX ); ++i ) for( int64_t j = INT_MIN; j <= int64_t( INT_MAX ); ++j ) { int i = int( j ); std::string s = biuFmt( int( i ) ); int r = parseBIU( s.c_str() ); if( r != i ) { printf( "i:%d biuFmt:%s r:%d\n", i, s.c_str(), r ); ++mismatches; } if( !( i & 0xFFFFFF ) ) { printf( " %08x", i ); fflush( stdout ); } } printf( "mismatches:%u\n", mismatches ); return 0; }